Merge branch 'bug4889_v2'

20 files changed, 201 insertions, 438 deletions

diff --git a/changes/clean_asprintf b/changes/clean_asprintf
new file mode 100644
index 0000000000..ebaabd775f
--- /dev/null
+++ b/changes/clean_asprintf
@@ -0,0 +1,5 @@
+  o Code simplifications and refactoring
+    - Use the smartlist_add_asprintf alias more consistently
+      throughout the codebase.
+    - Convert more instances of tor_snprintf+tor_strdup into
+      tor_asprintf.
diff --git a/src/common/compat.c b/src/common/compat.c
index ff9d877cd6..3af43e80c9 100644
--- a/src/common/compat.c
+++ b/src/common/compat.c
@@ -1351,31 +1351,19 @@ log_credential_status(void)
     return -1;
   } else {
     int i, retval = 0;
-    char *strgid;
     char *s = NULL;
     smartlist_t *elts = smartlist_create();
 
     for (i = 0; i<ngids; i++) {
-      strgid = tor_malloc(11);
-      if (tor_snprintf(strgid, 11, "%u", (unsigned)sup_gids[i]) < 0) {
-        log_warn(LD_GENERAL, "Error printing supplementary GIDs");
-        tor_free(strgid);
-        retval = -1;
-        goto error;
-      }
-      smartlist_add(elts, strgid);
+      smartlist_add_asprintf(elts, "%u", (unsigned)sup_gids[i]);
     }
 
     s = smartlist_join_strings(elts, " ", 0, NULL);
 
     log_fn(CREDENTIAL_LOG_LEVEL, LD_GENERAL, "Supplementary groups are: %s",s);
 
-   error:
     tor_free(s);
-    SMARTLIST_FOREACH(elts, char *, cp,
-    {
-      tor_free(cp);
-    });
+    SMARTLIST_FOREACH(elts, char *, cp, tor_free(cp));
     smartlist_free(elts);
     tor_free(sup_gids);
 
diff --git a/src/common/util.c b/src/common/util.c
index 22c816abcc..3d8b7dabef 100644
--- a/src/common/util.c
+++ b/src/common/util.c
@@ -1964,7 +1964,6 @@ int
 start_writing_to_file(const char *fname, int open_flags, int mode,
                       open_file_t **data_out)
 {
-  size_t tempname_len = strlen(fname)+16;
   open_file_t *new_file = tor_malloc_zero(sizeof(open_file_t));
   const char *open_name;
   int append = 0;
@@ -1975,7 +1974,6 @@ start_writing_to_file(const char *fname, int open_flags, int mode,
   tor_assert((open_flags & (O_BINARY|O_TEXT)) != 0);
 #endif
   new_file->fd = -1;
-  tor_assert(tempname_len > strlen(fname)); /*check for overflow*/
   new_file->filename = tor_strdup(fname);
   if (open_flags & O_APPEND) {
     open_name = fname;
@@ -1983,11 +1981,8 @@ start_writing_to_file(const char *fname, int open_flags, int mode,
     append = 1;
     open_flags &= ~O_APPEND;
   } else {
-    open_name = new_file->tempname = tor_malloc(tempname_len);
-    if (tor_snprintf(new_file->tempname, tempname_len, "%s.tmp", fname)<0) {
-      log_warn(LD_GENERAL, "Failed to generate filename");
-      goto err;
-    }
+    tor_asprintf(&new_file->tempname, "%s.tmp", fname);
+    open_name = new_file->tempname;
     /* We always replace an existing temporary file if there is one. */
     open_flags |= O_CREAT|O_TRUNC;
     open_flags &= ~O_EXCL;
@@ -2757,17 +2752,17 @@ tor_sscanf(const char *buf, const char *pattern, ...)
 /** Append the string produced by tor_asprintf(<b>pattern</b>, <b>...</b>)
  * to <b>sl</b>. */
 void
-smartlist_asprintf_add(struct smartlist_t *sl, const char *pattern, ...)
+smartlist_add_asprintf(struct smartlist_t *sl, const char *pattern, ...)
 {
   va_list ap;
   va_start(ap, pattern);
-  smartlist_vasprintf_add(sl, pattern, ap);
+  smartlist_add_vasprintf(sl, pattern, ap);
   va_end(ap);
 }
 
-/** va_list-based backend of smartlist_asprintf_add. */
+/** va_list-based backend of smartlist_add_asprintf. */
 void
-smartlist_vasprintf_add(struct smartlist_t *sl, const char *pattern,
+smartlist_add_vasprintf(struct smartlist_t *sl, const char *pattern,
                         va_list args)
 {
   char *str = NULL;
@@ -2786,14 +2781,12 @@ tor_listdir(const char *dirname)
 {
   smartlist_t *result;
 #ifdef MS_WINDOWS
-  char *pattern;
+  char *pattern=NULL;
   TCHAR tpattern[MAX_PATH] = {0};
   char name[MAX_PATH] = {0};
   HANDLE handle;
   WIN32_FIND_DATA findData;
-  size_t pattern_len = strlen(dirname)+16;
-  pattern = tor_malloc(pattern_len);
-  tor_snprintf(pattern, pattern_len, "%s\\*", dirname);
+  tor_asprintf(&pattern, "%s\\*", dirname);
 #ifdef UNICODE
   mbstowcs(tpattern,pattern,MAX_PATH);
 #else
diff --git a/src/common/util.h b/src/common/util.h
index cbc56d0816..b15b1ea56a 100644
--- a/src/common/util.h
+++ b/src/common/util.h
@@ -218,9 +218,9 @@ int tor_sscanf(const char *buf, const char *pattern, ...)
 #endif
   ;
 
-void smartlist_asprintf_add(struct smartlist_t *sl, const char *pattern, ...)
+void smartlist_add_asprintf(struct smartlist_t *sl, const char *pattern, ...)
   CHECK_PRINTF(2, 3);
-void smartlist_vasprintf_add(struct smartlist_t *sl, const char *pattern,
+void smartlist_add_vasprintf(struct smartlist_t *sl, const char *pattern,
                              va_list args);
 
 int hex_decode_digit(char c);
diff --git a/src/or/circuitbuild.c b/src/or/circuitbuild.c
index a9e5d22943..d157dbd1a2 100644
--- a/src/or/circuitbuild.c
+++ b/src/or/circuitbuild.c
@@ -675,8 +675,7 @@ circuit_build_times_update_state(circuit_build_times_t *cbt,
     if (histogram[i] == 0) continue;
     *next = line = tor_malloc_zero(sizeof(config_line_t));
     line->key = tor_strdup("CircuitBuildTimeBin");
-    line->value = tor_malloc(25);
-    tor_snprintf(line->value, 25, "%d %d",
+    tor_asprintf(&line->value, "%d %d",
             CBT_BIN_TO_MS(i), histogram[i]);
     next = &(line->next);
   }
@@ -1545,15 +1544,13 @@ circuit_list_path_impl(origin_circuit_t *circ, int verbose, int verbose_names)
 
   if (verbose) {
     const char *nickname = build_state_get_exit_nickname(circ->build_state);
-    char *cp;
-    tor_asprintf(&cp, "%s%s circ (length %d%s%s):",
+    smartlist_add_asprintf(elements, "%s%s circ (length %d%s%s):",
                  circ->build_state->is_internal ? "internal" : "exit",
                  circ->build_state->need_uptime ? " (high-uptime)" : "",
                  circ->build_state->desired_path_len,
                  circ->_base.state == CIRCUIT_STATE_OPEN ? "" : ", last hop ",
                  circ->_base.state == CIRCUIT_STATE_OPEN ? "" :
                  (nickname?nickname:"*unnamed*"));
-    smartlist_add(elements, cp);
   }
 
   hop = circ->cpath;
@@ -1594,11 +1591,8 @@ circuit_list_path_impl(origin_circuit_t *circ, int verbose, int verbose_names)
     }
     tor_assert(elt);
     if (verbose) {
-      size_t len = strlen(elt)+2+strlen(states[hop->state])+1;
-      char *v = tor_malloc(len);
       tor_assert(hop->state <= 2);
-      tor_snprintf(v,len,"%s(%s)",elt,states[hop->state]);
-      smartlist_add(elements, v);
+      smartlist_add_asprintf(elements,"%s(%s)",elt,states[hop->state]);
       tor_free(elt);
     } else {
       smartlist_add(elements, elt);
@@ -3599,19 +3593,17 @@ log_entry_guards(int severity)
   SMARTLIST_FOREACH_BEGIN(entry_guards, entry_guard_t *, e)
     {
       const char *msg = NULL;
-      char *cp;
       if (entry_is_live(e, 0, 1, 0, &msg))
-        tor_asprintf(&cp, "%s [%s] (up %s)",
+        smartlist_add_asprintf(elements, "%s [%s] (up %s)",
                      e->nickname,
                      hex_str(e->identity, DIGEST_LEN),
                      e->made_contact ? "made-contact" : "never-contacted");
       else
-        tor_asprintf(&cp, "%s [%s] (%s, %s)",
+        smartlist_add_asprintf(elements, "%s [%s] (%s, %s)",
                      e->nickname,
                      hex_str(e->identity, DIGEST_LEN),
                      msg,
                      e->made_contact ? "made-contact" : "never-contacted");
-      smartlist_add(elements, cp);
     }
   SMARTLIST_FOREACH_END(e);
 
@@ -3755,9 +3747,8 @@ remove_obsolete_entry_guards(time_t now)
       msg = "does not seem to be from any recognized version of Tor";
       version_is_bad = 1;
     } else {
-      size_t len = strlen(ver)+5;
-      char *tor_ver = tor_malloc(len);
-      tor_snprintf(tor_ver, len, "Tor %s", ver);
+      char *tor_ver = NULL;
+      tor_asprintf(&tor_ver, "Tor %s", ver);
       if ((tor_version_as_new_as(tor_ver, "0.1.0.10-alpha") &&
            !tor_version_as_new_as(tor_ver, "0.1.2.16-dev")) ||
           (tor_version_as_new_as(tor_ver, "0.2.0.0-alpha") &&
@@ -4445,10 +4436,8 @@ entry_guards_update_state(or_state_t *state)
         continue; /* don't write this one to disk */
       *next = line = tor_malloc_zero(sizeof(config_line_t));
       line->key = tor_strdup("EntryGuard");
-      line->value = tor_malloc(HEX_DIGEST_LEN+MAX_NICKNAME_LEN+2);
       base16_encode(dbuf, sizeof(dbuf), e->identity, DIGEST_LEN);
-      tor_snprintf(line->value,HEX_DIGEST_LEN+MAX_NICKNAME_LEN+2,
-                   "%s %s", e->nickname, dbuf);
+      tor_asprintf(&line->value, "%s %s", e->nickname, dbuf);
       next = &(line->next);
       if (e->unreachable_since) {
         *next = line = tor_malloc_zero(sizeof(config_line_t));
@@ -4472,15 +4461,11 @@ entry_guards_update_state(or_state_t *state)
           !strchr(e->chosen_by_version, ' ')) {
         char d[HEX_DIGEST_LEN+1];
         char t[ISO_TIME_LEN+1];
-        size_t val_len;
         *next = line = tor_malloc_zero(sizeof(config_line_t));
         line->key = tor_strdup("EntryGuardAddedBy");
-        val_len = (HEX_DIGEST_LEN+1+strlen(e->chosen_by_version)
-                   +1+ISO_TIME_LEN+1);
-        line->value = tor_malloc(val_len);
         base16_encode(d, sizeof(d), e->identity, DIGEST_LEN);
         format_iso_time(t, e->chosen_on_date);
-        tor_snprintf(line->value, val_len, "%s %s %s",
+        tor_asprintf(&line->value, "%s %s %s",
                      d, e->chosen_by_version, t);
         next = &(line->next);
       }
@@ -4512,8 +4497,6 @@ getinfo_helper_entry_guards(control_connection_t *conn,
     if (!entry_guards)
       entry_guards = smartlist_create();
     SMARTLIST_FOREACH_BEGIN(entry_guards, entry_guard_t *, e) {
-        size_t len = MAX_VERBOSE_NICKNAME_LEN+ISO_TIME_LEN+32;
-        char *c = tor_malloc(len);
         const char *status = NULL;
         time_t when = 0;
         const node_t *node;
@@ -4539,11 +4522,10 @@ getinfo_helper_entry_guards(control_connection_t *conn,
 
         if (when) {
           format_iso_time(tbuf, when);
-          tor_snprintf(c, len, "%s %s %s\n", nbuf, status, tbuf);
+          smartlist_add_asprintf(sl, "%s %s %s\n", nbuf, status, tbuf);
         } else {
-          tor_snprintf(c, len, "%s %s\n", nbuf, status);
+          smartlist_add_asprintf(sl, "%s %s\n", nbuf, status);
         }
-        smartlist_add(sl, c);
     } SMARTLIST_FOREACH_END(e);
     *answer = smartlist_join_strings(sl, "", 0, NULL);
     SMARTLIST_FOREACH(sl, char *, c, tor_free(c));
diff --git a/src/or/config.c b/src/or/config.c
index 341bc15d21..0763058d49 100644
--- a/src/or/config.c
+++ b/src/or/config.c
@@ -781,22 +781,20 @@ set_options(or_options_t *new_val, char **msg)
 extern const char tor_git_revision[]; /* from tor_main.c */
 
 /** The version of this Tor process, as parsed. */
-static char *_version = NULL;
+static char *the_tor_version = NULL;
 
 /** Return the current Tor version. */
 const char *
 get_version(void)
 {
-  if (_version == NULL) {
+  if (the_tor_version == NULL) {
     if (strlen(tor_git_revision)) {
-      size_t len = strlen(VERSION)+strlen(tor_git_revision)+16;
-      _version = tor_malloc(len);
-      tor_snprintf(_version, len, "%s (git-%s)", VERSION, tor_git_revision);
+      tor_asprintf(&the_tor_version, "%s (git-%s)", VERSION, tor_git_revision);
     } else {
-      _version = tor_strdup(VERSION);
+      the_tor_version = tor_strdup(VERSION);
     }
   }
-  return _version;
+  return the_tor_version;
 }
 
 /** Release additional memory allocated in options
@@ -841,7 +839,7 @@ config_free_all(void)
 
   tor_free(torrc_fname);
   tor_free(torrc_defaults_fname);
-  tor_free(_version);
+  tor_free(the_tor_version);
   tor_free(global_dirfrontpagecontents);
 }
 
@@ -1174,9 +1172,8 @@ options_act_reversible(const or_options_t *old_options, char **msg)
   control_ports_write_to_file();
 
   if (directory_caches_v2_dir_info(options)) {
-    size_t len = strlen(options->DataDirectory)+32;
-    char *fn = tor_malloc(len);
-    tor_snprintf(fn, len, "%s"PATH_SEPARATOR"cached-status",
+    char *fn = NULL;
+    tor_asprintf(&fn, "%s"PATH_SEPARATOR"cached-status",
                  options->DataDirectory);
     if (check_private_dir(fn, running_tor ? CPD_CREATE : CPD_CHECK,
                           options->User) < 0) {
@@ -1650,10 +1647,8 @@ options_act(const or_options_t *old_options)
 #ifdef WIN32
     if (!strcmp(actual_fname, "<default>")) {
       const char *conf_root = get_windows_conf_root();
-      size_t len = strlen(conf_root)+16;
       tor_free(actual_fname);
-      actual_fname = tor_malloc(len+1);
-      tor_snprintf(actual_fname, len, "%s\\geoip", conf_root);
+      tor_asprintf(&actual_fname, "%s\\geoip", conf_root);
     }
 #endif
     geoip_load_file(actual_fname, options);
@@ -3147,11 +3142,9 @@ config_dump(const config_format_t *fmt, const void *default_options,
     line = assigned = get_assigned_option(fmt, options, fmt->vars[i].name, 1);
 
     for (; line; line = line->next) {
-      char *tmp;
-      tor_asprintf(&tmp, "%s%s %s\n",
+      smartlist_add_asprintf(elements, "%s%s %s\n",
                    comment_option ? "# " : "",
                    line->key, line->value);
-      smartlist_add(elements, tmp);
     }
     config_free_lines(assigned);
   }
@@ -3159,9 +3152,7 @@ config_dump(const config_format_t *fmt, const void *default_options,
   if (fmt->extra) {
     line = *(config_line_t**)STRUCT_VAR_P(options, fmt->extra->var_offset);
     for (; line; line = line->next) {
-      char *tmp;
-      tor_asprintf(&tmp, "%s %s\n", line->key, line->value);
-      smartlist_add(elements, tmp);
+      smartlist_add_asprintf(elements, "%s %s\n", line->key, line->value);
     }
   }
 
@@ -3510,11 +3501,8 @@ options_validate(or_options_t *old_options, or_options_t *options,
       SMARTLIST_FOREACH(options->FirewallPorts, const char *, portno,
       {
         int p = atoi(portno);
-        char *s;
         if (p<0) continue;
-        s = tor_malloc(16);
-        tor_snprintf(s, 16, "*:%d", p);
-        smartlist_add(instead, s);
+        smartlist_add_asprintf(instead, "*:%d", p);
       });
       new_line->value = smartlist_join_strings(instead,",",0,NULL);
       /* These have been deprecated since 0.1.1.5-alpha-cvs */
@@ -6154,18 +6142,12 @@ write_configuration_file(const char *fname, const or_options_t *options)
 
   if (rename_old) {
     int i = 1;
-    size_t fn_tmp_len = strlen(fname)+32;
-    char *fn_tmp;
-    tor_assert(fn_tmp_len > strlen(fname)); /*check for overflow*/
-    fn_tmp = tor_malloc(fn_tmp_len);
+    char *fn_tmp = NULL;
     while (1) {
-      if (tor_snprintf(fn_tmp, fn_tmp_len, "%s.orig.%d", fname, i)<0) {
-        log_warn(LD_BUG, "tor_snprintf failed inexplicably");
-        tor_free(fn_tmp);
-        goto err;
-      }
+      tor_asprintf(&fn_tmp, "%s.orig.%d", fname, i);
       if (file_status(fn_tmp) == FN_NOENT)
         break;
+      tor_free(fn_tmp);
       ++i;
     }
     log_notice(LD_CONFIG, "Renaming old configuration file to \"%s\"", fn_tmp);
@@ -6612,13 +6594,13 @@ or_state_save_broken(char *fname)
 {
   int i;
   file_status_t status;
-  size_t len = strlen(fname)+16;
-  char *fname2 = tor_malloc(len);
+  char *fname2 = NULL;
   for (i = 0; i < 100; ++i) {
-    tor_snprintf(fname2, len, "%s.%d", fname, i);
+    tor_asprintf(&fname2, "%s.%d", fname, i);
     status = file_status(fname2);
     if (status == FN_NOENT)
       break;
+    tor_free(fname2);
   }
   if (i == 100) {
     log_warn(LD_BUG, "Unable to parse state in \"%s\"; too many saved bad "
@@ -6994,7 +6976,6 @@ getinfo_helper_config(control_connection_t *conn,
     for (i = 0; _option_vars[i].name; ++i) {
       const config_var_t *var = &_option_vars[i];
       const char *type;
-      char *line;
       switch (var->type) {
         case CONFIG_TYPE_STRING: type = "String"; break;
         case CONFIG_TYPE_FILENAME: type = "Filename"; break;
@@ -7018,8 +6999,7 @@ getinfo_helper_config(control_connection_t *conn,
       }
       if (!type)
         continue;
-      tor_asprintf(&line, "%s %s\n",var->name,type);
-      smartlist_add(sl, line);
+      smartlist_add_asprintf(sl, "%s %s\n",var->name,type);
     }
     *answer = smartlist_join_strings(sl, "", 0, NULL);
     SMARTLIST_FOREACH(sl, char *, c, tor_free(c));
diff --git a/src/or/connection_edge.c b/src/or/connection_edge.c
index aba9ba2727..dcb9cae423 100644
--- a/src/or/connection_edge.c
+++ b/src/or/connection_edge.c
@@ -909,13 +909,10 @@ addressmap_ent_remove(const char *address, addressmap_entry_t *ent)
 static void
 clear_trackexithost_mappings(const char *exitname)
 {
-  char *suffix;
-  size_t suffix_len;
+  char *suffix = NULL;
   if (!addressmap || !exitname)
     return;
-  suffix_len = strlen(exitname) + 16;
-  suffix = tor_malloc(suffix_len);
-  tor_snprintf(suffix, suffix_len, ".%s.exit", exitname);
+  tor_asprintf(&suffix, ".%s.exit", exitname);
   tor_strlower(suffix);
 
   STRMAP_FOREACH_MODIFY(addressmap, address, addressmap_entry_t *, ent) {
@@ -1165,11 +1162,10 @@ addressmap_rewrite(char *address, size_t maxlen, time_t *expires_out)
 static int
 addressmap_rewrite_reverse(char *address, size_t maxlen, time_t *expires_out)
 {
-  size_t len = maxlen + 16;
-  char *s = tor_malloc(len), *cp;
+  char *s, *cp;
   addressmap_entry_t *ent;
   int r = 0;
-  tor_snprintf(s, len, "REVERSE[%s]", address);
+  tor_asprintf(&s, "REVERSE[%s]", address);
   ent = strmap_get(addressmap, s);
   if (ent) {
     cp = tor_strdup(escaped_safe_str_client(ent->new_address));
@@ -1403,9 +1399,8 @@ client_dns_set_reverse_addressmap(const char *address, const char *v,
                                   const char *exitname,
                                   int ttl)
 {
-  size_t len = strlen(address) + 16;
-  char *s = tor_malloc(len);
-  tor_snprintf(s, len, "REVERSE[%s]", address);
+  char *s = NULL;
+  tor_asprintf(&s, "REVERSE[%s]", address);
   client_dns_set_addressmap_impl(s, v, exitname, ttl);
   tor_free(s);
 }
@@ -1689,21 +1684,18 @@ addressmap_get_mappings(smartlist_t *sl, time_t min_expires,
          addressmap_ent_remove(key, val);
          continue;
        } else if (val->new_address) {
-         size_t len = strlen(key)+strlen(val->new_address)+ISO_TIME_LEN+5;
-         char *line = tor_malloc(len);
          if (want_expiry) {
            if (val->expires < 3 || val->expires == TIME_MAX)
-             tor_snprintf(line, len, "%s %s NEVER", key, val->new_address);
+             smartlist_add_asprintf(sl, "%s %s NEVER", key, val->new_address);
            else {
              char time[ISO_TIME_LEN+1];
              format_iso_time(time, val->expires);
-             tor_snprintf(line, len, "%s %s \"%s\"", key, val->new_address,
+             smartlist_add_asprintf(sl, "%s %s \"%s\"", key, val->new_address,
                           time);
            }
          } else {
-           tor_snprintf(line, len, "%s %s", key, val->new_address);
+           smartlist_add_asprintf(sl, "%s %s", key, val->new_address);
          }
-         smartlist_add(sl, line);
        }
      }
      iter = strmap_iter_next(addressmap,iter);
diff --git a/src/or/control.c b/src/or/control.c
index 60c62b15a5..1d2d8dd392 100644
--- a/src/or/control.c
+++ b/src/or/control.c
@@ -525,18 +525,15 @@ control_ports_write_to_file(void)
   lines = smartlist_create();
 
   SMARTLIST_FOREACH_BEGIN(get_connection_array(), const connection_t *, conn) {
-    char *port_str = NULL;
     if (conn->type != CONN_TYPE_CONTROL_LISTENER || conn->marked_for_close)
       continue;
 #ifdef AF_UNIX
     if (conn->socket_family == AF_UNIX) {
-      tor_asprintf(&port_str, "UNIX_PORT=%s\n", conn->address);
-      smartlist_add(lines, port_str);
+      smartlist_add_asprintf(lines, "UNIX_PORT=%s\n", conn->address);
       continue;
     }
 #endif
-    tor_asprintf(&port_str, "PORT=%s:%d\n", conn->address, conn->port);
-    smartlist_add(lines, port_str);
+    smartlist_add_asprintf(lines, "PORT=%s:%d\n", conn->address, conn->port);
   } SMARTLIST_FOREACH_END(conn);
 
   joined = smartlist_join_strings(lines, "", 0, NULL);
@@ -700,7 +697,6 @@ control_setconf_helper(control_connection_t *conn, uint32_t len, char *body,
     if (*eq == '=') {
       char *val=NULL;
       size_t val_len=0;
-      size_t ent_len;
       if (*body != '\"') {
         char *val_start = body;
         while (!TOR_ISSPACE(*body))
@@ -718,9 +714,7 @@ control_setconf_helper(control_connection_t *conn, uint32_t len, char *body,
           return 0;
         }
       }
-      ent_len = strlen(key)+val_len+3;
-      entry = tor_malloc(ent_len+1);
-      tor_snprintf(entry, ent_len, "%s %s", key, val);
+      tor_asprintf(&entry, "%s %s", key, val);
       tor_free(key);
       tor_free(val);
     } else {
@@ -820,19 +814,13 @@ handle_control_getconf(control_connection_t *conn, uint32_t body_len,
       config_line_t *answer = option_get_assignment(options,q);
       if (!answer) {
         const char *name = option_get_canonical_name(q);
-        size_t alen = strlen(name)+8;
-        char *astr = tor_malloc(alen);
-        tor_snprintf(astr, alen, "250-%s\r\n", name);
-        smartlist_add(answers, astr);
+        smartlist_add_asprintf(answers, "250-%s\r\n", name);
       }
 
       while (answer) {
         config_line_t *next;
-        size_t alen = strlen(answer->key)+strlen(answer->value)+8;
-        char *astr = tor_malloc(alen);
-        tor_snprintf(astr, alen, "250-%s=%s\r\n",
+        smartlist_add_asprintf(answers, "250-%s=%s\r\n",
                      answer->key, answer->value);
-        smartlist_add(answers, astr);
 
         next = answer->next;
         tor_free(answer->key);
@@ -1307,12 +1295,9 @@ handle_control_mapaddress(control_connection_t *conn, uint32_t len,
     if (smartlist_len(elts) == 2) {
       const char *from = smartlist_get(elts,0);
       const char *to = smartlist_get(elts,1);
-      size_t anslen = strlen(line)+512;
-      char *ans = tor_malloc(anslen);
       if (address_is_invalid_destination(to, 1)) {
-        tor_snprintf(ans, anslen,
+        smartlist_add_asprintf(reply,
                      "512-syntax error: invalid address '%s'", to);
-        smartlist_add(reply, ans);
         log_warn(LD_CONTROL,
                  "Skipping invalid argument '%s' in MapAddress msg", to);
       } else if (!strcmp(from, ".") || !strcmp(from, "0.0.0.0")) {
@@ -1320,28 +1305,22 @@ handle_control_mapaddress(control_connection_t *conn, uint32_t len,
               !strcmp(from,".") ? RESOLVED_TYPE_HOSTNAME : RESOLVED_TYPE_IPV4,
                tor_strdup(to));
         if (!address) {
-          tor_snprintf(ans, anslen,
+          smartlist_add_asprintf(reply,
                        "451-resource exhausted: skipping '%s'", line);
-          smartlist_add(reply, ans);
           log_warn(LD_CONTROL,
                    "Unable to allocate address for '%s' in MapAddress msg",
                    safe_str_client(line));
         } else {
-          tor_snprintf(ans, anslen, "250-%s=%s", address, to);
-          smartlist_add(reply, ans);
+          smartlist_add_asprintf(reply, "250-%s=%s", address, to);
         }
       } else {
         addressmap_register(from, tor_strdup(to), 1,
                             ADDRMAPSRC_CONTROLLER, 0, 0);
-        tor_snprintf(ans, anslen, "250-%s", line);
-        smartlist_add(reply, ans);
+        smartlist_add_asprintf(reply, "250-%s", line);
       }
     } else {
-      size_t anslen = strlen(line)+256;
-      char *ans = tor_malloc(anslen);
-      tor_snprintf(ans, anslen, "512-syntax error: mapping '%s' is "
+      smartlist_add_asprintf(reply, "512-syntax error: mapping '%s' is "
                    "not of expected form 'foo=bar'.", line);
-      smartlist_add(reply, ans);
       log_info(LD_CONTROL, "Skipping MapAddress '%s': wrong "
                            "number of items.",
                            safe_str_client(line));
@@ -1558,7 +1537,6 @@ getinfo_helper_listeners(control_connection_t *control_conn,
 
   res = smartlist_create();
   SMARTLIST_FOREACH_BEGIN(get_connection_array(), connection_t *, conn) {
-    char *addr;
     struct sockaddr_storage ss;
     socklen_t ss_len = sizeof(ss);
 
@@ -1566,14 +1544,13 @@ getinfo_helper_listeners(control_connection_t *control_conn,
       continue;
 
     if (getsockname(conn->s, (struct sockaddr *)&ss, &ss_len) < 0) {
-      tor_asprintf(&addr, "%s:%d", conn->address, (int)conn->port);
+      smartlist_add_asprintf(res, "%s:%d", conn->address, (int)conn->port);
     } else {
       char *tmp = tor_sockaddr_to_str((struct sockaddr *)&ss);
-      addr = esc_for_log(tmp);
+      smartlist_add(res, esc_for_log(tmp));
       tor_free(tmp);
     }
-    if (addr)
-      smartlist_add(res, addr);
+
   } SMARTLIST_FOREACH_END(conn);
 
   *answer = smartlist_join_strings(res, " ", 0, NULL);
@@ -1675,13 +1652,13 @@ getinfo_helper_dir(control_connection_t *control_conn,
                               ri->cache_info.annotations_len);
     }
   } else if (!strcmpstart(question, "dir/server/")) {
-    size_t answer_len = 0, url_len = strlen(question)+2;
-    char *url = tor_malloc(url_len);
+    size_t answer_len = 0;
+    char *url = NULL;
     smartlist_t *descs = smartlist_create();
     const char *msg;
     int res;
     char *cp;
-    tor_snprintf(url, url_len, "/tor/%s", question+4);
+    tor_asprintf(&url, "/tor/%s", question+4);
     res = dirserv_get_routerdescs(descs, url, &msg);
     if (res) {
       log_warn(LD_CONTROL, "getinfo '%s': %s", question, msg);
@@ -1798,7 +1775,6 @@ circuit_describe_status_for_controller(origin_circuit_t *circ)
   }
 
   {
-    char *buildflags = NULL;
     cpath_build_state_t *build_state = circ->build_state;
     smartlist_t *flaglist = smartlist_create();
     char *flaglist_joined;
@@ -1816,8 +1792,7 @@ circuit_describe_status_for_controller(origin_circuit_t *circ)
     if (smartlist_len(flaglist)) {
       flaglist_joined = smartlist_join_strings(flaglist, ",", 0, NULL);
 
-      tor_asprintf(&buildflags, "BUILD_FLAGS=%s", flaglist_joined);
-      smartlist_add(descparts, buildflags);
+      smartlist_add_asprintf(descparts, "BUILD_FLAGS=%s", flaglist_joined);
 
       tor_free(flaglist_joined);
     }
@@ -1825,43 +1800,28 @@ circuit_describe_status_for_controller(origin_circuit_t *circ)
     smartlist_free(flaglist);
   }
 
-  {
-    char *purpose = NULL;
-    tor_asprintf(&purpose, "PURPOSE=%s",
-                 circuit_purpose_to_controller_string(circ->_base.purpose));
-    smartlist_add(descparts, purpose);
-  }
+  smartlist_add_asprintf(descparts, "PURPOSE=%s",
+                    circuit_purpose_to_controller_string(circ->_base.purpose));
 
   {
-    char *hs_state_arg = NULL;
     const char *hs_state =
       circuit_purpose_to_controller_hs_state_string(circ->_base.purpose);
 
     if (hs_state != NULL) {
-      tor_asprintf(&hs_state_arg, "HS_STATE=%s",
-                   hs_state);
-
-      smartlist_add(descparts, hs_state_arg);
+      smartlist_add_asprintf(descparts, "HS_STATE=%s", hs_state);
     }
   }
 
   if (circ->rend_data != NULL) {
-    char *rend_query_arg = NULL;
-
-    tor_asprintf(&rend_query_arg, "REND_QUERY=%s",
+    smartlist_add_asprintf(descparts, "REND_QUERY=%s",
                  circ->rend_data->onion_address);
-
-    smartlist_add(descparts, rend_query_arg);
   }
 
   {
-    char *time_created_arg = NULL;
     char tbuf[ISO_TIME_USEC_LEN+1];
     format_iso_time_nospace_usec(tbuf, &circ->_base.timestamp_created);
 
-    tor_asprintf(&time_created_arg, "TIME_CREATED=%s", tbuf);
-
-    smartlist_add(descparts, time_created_arg);
+    smartlist_add_asprintf(descparts, "TIME_CREATED=%s", tbuf);
   }
 
   rv = smartlist_join_strings(descparts, " ", 0, NULL);
@@ -1885,8 +1845,7 @@ getinfo_helper_events(control_connection_t *control_conn,
     smartlist_t *status = smartlist_create();
     for (circ_ = _circuit_get_global_list(); circ_; circ_ = circ_->next) {
       origin_circuit_t *circ;
-      char *s, *circdesc;
-      size_t slen;
+      char *circdesc;
       const char *state;
       if (! CIRCUIT_IS_ORIGIN(circ_) || circ_->marked_for_close)
         continue;
@@ -1901,12 +1860,9 @@ getinfo_helper_events(control_connection_t *control_conn,
 
       circdesc = circuit_describe_status_for_controller(circ);
 
-      slen = strlen(circdesc)+strlen(state)+30;
-      s = tor_malloc(slen+1);
-      tor_snprintf(s, slen, "%lu %s%s%s",
+      smartlist_add_asprintf(status, "%lu %s%s%s",
                    (unsigned long)circ->global_identifier,
                    state, *circdesc ? " " : "", circdesc);
-      smartlist_add(status, s);
       tor_free(circdesc);
     }
     *answer = smartlist_join_strings(status, "\r\n", 0, NULL);
@@ -1919,8 +1875,6 @@ getinfo_helper_events(control_connection_t *control_conn,
     SMARTLIST_FOREACH_BEGIN(conns, connection_t *, base_conn) {
       const char *state;
       entry_connection_t *conn;
-      char *s;
-      size_t slen;
       circuit_t *circ;
       origin_circuit_t *origin_circ = NULL;
       if (base_conn->type != CONN_TYPE_AP ||
@@ -1955,14 +1909,11 @@ getinfo_helper_events(control_connection_t *control_conn,
       if (circ && CIRCUIT_IS_ORIGIN(circ))
         origin_circ = TO_ORIGIN_CIRCUIT(circ);
       write_stream_target_to_buf(conn, buf, sizeof(buf));
-      slen = strlen(buf)+strlen(state)+32;
-      s = tor_malloc(slen+1);
-      tor_snprintf(s, slen, "%lu %s %lu %s",
+      smartlist_add_asprintf(status, "%lu %s %lu %s",
                    (unsigned long) base_conn->global_identifier,state,
                    origin_circ?
                          (unsigned long)origin_circ->global_identifier : 0ul,
                    buf);
-      smartlist_add(status, s);
     } SMARTLIST_FOREACH_END(base_conn);
     *answer = smartlist_join_strings(status, "\r\n", 0, NULL);
     SMARTLIST_FOREACH(status, char *, cp, tor_free(cp));
@@ -1972,9 +1923,7 @@ getinfo_helper_events(control_connection_t *control_conn,
     smartlist_t *status = smartlist_create();
     SMARTLIST_FOREACH_BEGIN(conns, connection_t *, base_conn) {
       const char *state;
-      char *s;
       char name[128];
-      size_t slen;
       or_connection_t *conn;
       if (base_conn->type != CONN_TYPE_OR || base_conn->marked_for_close)
         continue;
@@ -1986,10 +1935,7 @@ getinfo_helper_events(control_connection_t *control_conn,
       else
         state = "NEW";
       orconn_target_get_name(name, sizeof(name), conn);
-      slen = strlen(name)+strlen(state)+2;
-      s = tor_malloc(slen+1);
-      tor_snprintf(s, slen, "%s %s", name, state);
-      smartlist_add(status, s);
+      smartlist_add_asprintf(status, "%s %s", name, state);
     } SMARTLIST_FOREACH_END(base_conn);
     *answer = smartlist_join_strings(status, "\r\n", 0, NULL);
     SMARTLIST_FOREACH(status, char *, cp, tor_free(cp));
@@ -2033,8 +1979,7 @@ getinfo_helper_events(control_connection_t *control_conn,
     } else if (!strcmp(question, "status/reachability-succeeded/dir")) {
       *answer = tor_strdup(check_whether_dirport_reachable() ? "1" : "0");
     } else if (!strcmp(question, "status/reachability-succeeded")) {
-      *answer = tor_malloc(16);
-      tor_snprintf(*answer, 16, "OR=%d DIR=%d",
+      tor_asprintf(answer, "OR=%d DIR=%d",
                    check_whether_orport_reachable() ? 1 : 0,
                    check_whether_dirport_reachable() ? 1 : 0);
     } else if (!strcmp(question, "status/bootstrap-phase")) {
@@ -2070,9 +2015,7 @@ getinfo_helper_events(control_connection_t *control_conn,
           }
       } else if (!strcmp(question, "status/version/num-versioning") ||
                  !strcmp(question, "status/version/num-concurring")) {
-        char s[33];
-        tor_snprintf(s, sizeof(s), "%d", get_n_authorities(V3_DIRINFO));
-        *answer = tor_strdup(s);
+        tor_asprintf(answer, "%d", get_n_authorities(V3_DIRINFO));
         log_warn(LD_GENERAL, "%s is deprecated; it no longer gives useful "
                  "information", question);
       }
@@ -2218,18 +2161,16 @@ static char *
 list_getinfo_options(void)
 {
   int i;
-  char *buf=NULL;
   smartlist_t *lines = smartlist_create();
   char *ans;
   for (i = 0; getinfo_items[i].varname; ++i) {
     if (!getinfo_items[i].desc)
       continue;
 
-    tor_asprintf(&buf, "%s%s -- %s\n",
+    smartlist_add_asprintf(lines, "%s%s -- %s\n",
                  getinfo_items[i].varname,
                  getinfo_items[i].is_prefix ? "*" : "",
                  getinfo_items[i].desc);
-    smartlist_add(lines, buf);
   }
   smartlist_sort_strings(lines);
 
@@ -3551,8 +3492,7 @@ control_event_stream_status(entry_connection_t *conn, stream_status_event_t tp,
     const char *reason_str = stream_end_reason_to_control_string(reason_code);
     char *r = NULL;
     if (!reason_str) {
-      r = tor_malloc(16);
-      tor_snprintf(r, 16, " UNKNOWN_%d", reason_code);
+      tor_asprintf(&r, " UNKNOWN_%d", reason_code);
       reason_str = r;
     }
     if (reason_code & END_STREAM_REASON_FLAG_REMOTE)
@@ -3837,16 +3777,13 @@ control_event_descriptors_changed(smartlist_t *routers)
   {
     smartlist_t *names = smartlist_create();
     char *ids;
-    size_t names_len;
     SMARTLIST_FOREACH(routers, routerinfo_t *, ri, {
         char *b = tor_malloc(MAX_VERBOSE_NICKNAME_LEN+1);
         router_get_verbose_nickname(b, ri);
         smartlist_add(names, b);
       });
-    ids = smartlist_join_strings(names, " ", 0, &names_len);
-    names_len = strlen(ids)+32;
-    msg = tor_malloc(names_len);
-    tor_snprintf(msg, names_len, "650 NEWDESC %s\r\n", ids);
+    ids = smartlist_join_strings(names, " ", 0, NULL);
+    tor_asprintf(&msg, "650 NEWDESC %s\r\n", ids);
     send_control_event_string(EVENT_NEW_DESC, ALL_FORMATS, msg);
     tor_free(ids);
     tor_free(msg);
@@ -4239,9 +4176,9 @@ control_event_conf_changed(smartlist_t *elements)
     char *k = smartlist_get(elements, i);
     char *v = smartlist_get(elements, i+1);
     if (v == NULL) {
-      smartlist_asprintf_add(lines, "650-%s", k);
+      smartlist_add_asprintf(lines, "650-%s", k);
     } else {
-      smartlist_asprintf_add(lines, "650-%s=%s", k, v);
+      smartlist_add_asprintf(lines, "650-%s=%s", k, v);
     }
   }
   result = smartlist_join_strings(lines, "\r\n", 0, NULL);
diff --git a/src/or/directory.c b/src/or/directory.c
index 12636bac33..94c37f18d3 100644
--- a/src/or/directory.c
+++ b/src/or/directory.c
@@ -1124,9 +1124,7 @@ directory_send_command(dir_connection_t *conn,
   smartlist_t *headers = smartlist_create();
   char *url;
   char request[8192];
-  char *header;
   const char *httpcommand = NULL;
-  size_t len;
 
   tor_assert(conn);
   tor_assert(conn->_base.type == CONN_TYPE_DIR);
@@ -1147,8 +1145,7 @@ directory_send_command(dir_connection_t *conn,
   if (if_modified_since) {
     char b[RFC1123_TIME_LEN+1];
     format_rfc1123_time(b, if_modified_since);
-    tor_asprintf(&header, "If-Modified-Since: %s\r\n", b);
-    smartlist_add(headers, header);
+    smartlist_add_asprintf(headers, "If-Modified-Since: %s\r\n", b);
   }
 
   /* come up with some proxy lines, if we're using one. */
@@ -1163,11 +1160,10 @@ directory_send_command(dir_connection_t *conn,
         log_warn(LD_BUG, "Encoding http authenticator failed");
     }
     if (base64_authenticator) {
-      tor_asprintf(&header,
+      smartlist_add_asprintf(headers,
                    "Proxy-Authorization: Basic %s\r\n",
                    base64_authenticator);
       tor_free(base64_authenticator);
-      smartlist_add(headers, header);
     }
   } else {
     proxystring[0] = 0;
@@ -1177,9 +1173,7 @@ directory_send_command(dir_connection_t *conn,
     case DIR_PURPOSE_FETCH_V2_NETWORKSTATUS:
       tor_assert(resource);
       httpcommand = "GET";
-      len = strlen(resource)+32;
-      url = tor_malloc(len);
-      tor_snprintf(url, len, "/tor/status/%s", resource);
+      tor_asprintf(&url, "/tor/status/%s", resource);
       break;
     case DIR_PURPOSE_FETCH_CONSENSUS:
       /* resource is optional.  If present, it's a flavor name */
@@ -1194,17 +1188,13 @@ directory_send_command(dir_connection_t *conn,
       tor_assert(resource);
       tor_assert(!payload);
       httpcommand = "GET";
-      len = strlen(resource)+32;
-      url = tor_malloc(len);
-      tor_snprintf(url, len, "/tor/keys/%s", resource);
+      tor_asprintf(&url, "/tor/keys/%s", resource);
       break;
     case DIR_PURPOSE_FETCH_STATUS_VOTE:
       tor_assert(resource);
       tor_assert(!payload);
       httpcommand = "GET";
-      len = strlen(resource)+32;
-      url = tor_malloc(len);
-      tor_snprintf(url, len, "/tor/status-vote/next/%s.z", resource);
+      tor_asprintf(&url, "/tor/status-vote/next/%s.z", resource);
       break;
     case DIR_PURPOSE_FETCH_DETACHED_SIGNATURES:
       tor_assert(!resource);
@@ -1215,16 +1205,12 @@ directory_send_command(dir_connection_t *conn,
     case DIR_PURPOSE_FETCH_SERVERDESC:
       tor_assert(resource);
       httpcommand = "GET";
-      len = strlen(resource)+32;
-      url = tor_malloc(len);
-      tor_snprintf(url, len, "/tor/server/%s", resource);
+      tor_asprintf(&url, "/tor/server/%s", resource);
       break;
     case DIR_PURPOSE_FETCH_EXTRAINFO:
       tor_assert(resource);
       httpcommand = "GET";
-      len = strlen(resource)+32;
-      url = tor_malloc(len);
-      tor_snprintf(url, len, "/tor/extra/%s", resource);
+      tor_asprintf(&url, "/tor/extra/%s", resource);
       break;
     case DIR_PURPOSE_FETCH_MICRODESC:
       tor_assert(resource);
@@ -1238,8 +1224,7 @@ directory_send_command(dir_connection_t *conn,
       httpcommand = "POST";
       url = tor_strdup("/tor/");
       if (why) {
-        tor_asprintf(&header, "X-Desc-Gen-Reason: %s\r\n", why);
-        smartlist_add(headers, header);
+        smartlist_add_asprintf(headers, "X-Desc-Gen-Reason: %s\r\n", why);
       }
       break;
     }
@@ -1260,9 +1245,7 @@ directory_send_command(dir_connection_t *conn,
       tor_assert(strlen(resource) <= REND_DESC_ID_V2_LEN_BASE32);
       tor_assert(!payload);
       httpcommand = "GET";
-      len = strlen(resource) + 32;
-      url = tor_malloc(len);
-      tor_snprintf(url, len, "/tor/rendezvous2/%s", resource);
+      tor_asprintf(&url, "/tor/rendezvous2/%s", resource);
       break;
     case DIR_PURPOSE_UPLOAD_RENDDESC:
       tor_assert(!resource);
@@ -1294,15 +1277,16 @@ directory_send_command(dir_connection_t *conn,
   tor_free(url);
 
   if (!strcmp(httpcommand, "POST") || payload) {
-    tor_asprintf(&header, "Content-Length: %lu\r\n",
+    smartlist_add_asprintf(headers, "Content-Length: %lu\r\n",
                  payload ? (unsigned long)payload_len : 0);
-    smartlist_add(headers, header);
   }
 
-  header = smartlist_join_strings(headers, "", 0, NULL);
-  tor_snprintf(request, sizeof(request), " HTTP/1.0\r\nHost: %s\r\n%s\r\n",
-               hoststring, header);
-  tor_free(header);
+  {
+    char *header = smartlist_join_strings(headers, "", 0, NULL);
+    tor_snprintf(request, sizeof(request), " HTTP/1.0\r\nHost: %s\r\n%s\r\n",
+                 hoststring, header);
+    tor_free(header);
+  }
 
   connection_write_to_buf(request, strlen(request), TO_CONN(conn));
 
@@ -2479,11 +2463,9 @@ note_client_request(int purpose, int compressed, size_t bytes)
     case DIR_PURPOSE_UPLOAD_RENDDESC_V2:  kind = "dl/ul-rend2"; break;
   }
   if (kind) {
-    key = tor_malloc(256);
-    tor_snprintf(key, 256, "%s%s", kind, compressed?".z":"");
+    tor_asprintf(&key, "%s%s", kind, compressed?".z":"");
   } else {
-    key = tor_malloc(256);
-    tor_snprintf(key, 256, "unknown purpose (%d)%s",
+    tor_asprintf(&key, "unknown purpose (%d)%s",
                  purpose, compressed?".z":"");
   }
   note_request(key, bytes);
@@ -2522,7 +2504,6 @@ char *
 directory_dump_request_log(void)
 {
   smartlist_t *lines;
-  char tmp[256];
   char *result;
   strmap_iter_t *iter;
 
@@ -2538,9 +2519,8 @@ directory_dump_request_log(void)
     request_t *r;
     strmap_iter_get(iter, &key, &val);
     r = val;
-    tor_snprintf(tmp, sizeof(tmp), "%s  "U64_FORMAT"  "U64_FORMAT"\n",
+    smartlist_add_asprintf(lines, "%s  "U64_FORMAT"  "U64_FORMAT"\n",
                  key, U64_PRINTF_ARG(r->bytes), U64_PRINTF_ARG(r->count));
-    smartlist_add(lines, tor_strdup(tmp));
   }
   smartlist_sort_strings(lines);
   result = smartlist_join_strings(lines, "", 0, NULL);
@@ -3294,8 +3274,7 @@ directory_handle_command_get(dir_connection_t *conn, const char *headers,
 
 #if defined(EXPORTMALLINFO) && defined(HAVE_MALLOC_H) && defined(HAVE_MALLINFO)
 #define ADD_MALLINFO_LINE(x) do {                               \
-    tor_snprintf(tmp, sizeof(tmp), "%s %d\n", #x, mi.x);        \
-    smartlist_add(lines, tor_strdup(tmp));                      \
+    smartlist_add_asprintf(lines, "%s %d\n", #x, mi.x);        \
   }while(0);
 
   if (!strcmp(url,"/tor/mallinfo.txt") &&
@@ -3304,7 +3283,6 @@ directory_handle_command_get(dir_connection_t *conn, const char *headers,
     size_t len;
     struct mallinfo mi;
     smartlist_t *lines;
-    char tmp[256];
 
     memset(&mi, 0, sizeof(mi));
     mi = mallinfo();
diff --git a/src/or/dirserv.c b/src/or/dirserv.c
index e5995697dd..cc8dffb7ff 100644
--- a/src/or/dirserv.c
+++ b/src/or/dirserv.c
@@ -2906,9 +2906,7 @@ generate_v2_networkstatus_opinion(void)
     contact = "(none)";
 
   if (versioning) {
-    size_t v_len = 64+strlen(client_versions)+strlen(server_versions);
-    version_lines = tor_malloc(v_len);
-    tor_snprintf(version_lines, v_len,
+    tor_asprintf(&version_lines,
                  "client-versions %s\nserver-versions %s\n",
                  client_versions, server_versions);
   } else {
diff --git a/src/or/dirvote.c b/src/or/dirvote.c
index 3bb165aeea..f81ffa00be 100644
--- a/src/or/dirvote.c
+++ b/src/or/dirvote.c
@@ -581,15 +581,13 @@ make_consensus_method_list(int low, int high, const char *separator)
 {
   char *list;
 
-  char b[32];
   int i;
   smartlist_t *lst;
   lst = smartlist_create();
   for (i = low; i <= high; ++i) {
     if (!consensus_method_is_supported(i))
       continue;
-    tor_snprintf(b, sizeof(b), "%d", i);
-    smartlist_add(lst, tor_strdup(b));
+    smartlist_add_asprintf(lst, "%d", i);
   }
   list = smartlist_join_strings(lst, separator, 0, NULL);
   tor_assert(list);
@@ -810,8 +808,6 @@ networkstatus_compute_bw_weights_v10(smartlist_t *chunks, int64_t G,
   int64_t Wmg = -1, Wme = -1, Wmd = -1;
   int64_t Wed = -1, Wee = -1;
   const char *casename;
-  char buf[512];
-  int r;
 
   if (G <= 0 || M <= 0 || E <= 0 || D <= 0) {
     log_warn(LD_DIR, "Consensus with empty bandwidth: "
@@ -1019,7 +1015,7 @@ networkstatus_compute_bw_weights_v10(smartlist_t *chunks, int64_t G,
    *
    * NOTE: This list is sorted.
    */
-  r = tor_snprintf(buf, sizeof(buf),
+  smartlist_add_asprintf(chunks,
      "bandwidth-weights Wbd=%d Wbe=%d Wbg=%d Wbm=%d "
      "Wdb=%d "
      "Web=%d Wed=%d Wee=%d Weg=%d Wem=%d "
@@ -1030,13 +1026,6 @@ networkstatus_compute_bw_weights_v10(smartlist_t *chunks, int64_t G,
      (int)weight_scale, (int)Wed, (int)Wee, (int)Wed, (int)Wee,
      (int)weight_scale, (int)Wgd, (int)Wgg, (int)Wgg,
      (int)weight_scale, (int)Wmd, (int)Wme, (int)Wmg, (int)weight_scale);
-  if (r<0) {
-    log_warn(LD_BUG,
-             "Not enough space in buffer for bandwidth-weights line.");
-    *buf = '\0';
-    return 0;
-  }
-  smartlist_add(chunks, tor_strdup(buf));
 
   log_notice(LD_CIRC, "Computed bandwidth weights for %s with v10: "
              "G="I64_FORMAT" M="I64_FORMAT" E="I64_FORMAT" D="I64_FORMAT
@@ -1060,8 +1049,6 @@ networkstatus_compute_bw_weights_v9(smartlist_t *chunks, int64_t G, int64_t M,
   int64_t Wmg = -1, Wme = -1, Wmd = -1;
   int64_t Wed = -1, Wee = -1;
   const char *casename;
-  char buf[512];
-  int r;
 
   if (G <= 0 || M <= 0 || E <= 0 || D <= 0) {
     log_warn(LD_DIR, "Consensus with empty bandwidth: "
@@ -1323,7 +1310,7 @@ networkstatus_compute_bw_weights_v9(smartlist_t *chunks, int64_t G, int64_t M,
    *
    * NOTE: This list is sorted.
    */
-  r = tor_snprintf(buf, sizeof(buf),
+  smartlist_add_asprintf(chunks,
      "Wbd=%d Wbe=%d Wbg=%d Wbm=%d "
      "Wdb=%d "
      "Web=%d Wed=%d Wee=%d Weg=%d Wem=%d "
@@ -1334,12 +1321,7 @@ networkstatus_compute_bw_weights_v9(smartlist_t *chunks, int64_t G, int64_t M,
      (int)weight_scale, (int)Wed, (int)Wee, (int)Wed, (int)Wee,
      (int)weight_scale, (int)Wgd, (int)Wgg, (int)Wgg,
      (int)weight_scale, (int)Wmd, (int)Wme, (int)Wmg, (int)weight_scale);
-  if (r<0) {
-    log_warn(LD_BUG,
-             "Not enough space in buffer for bandwidth-weights line.");
-    *buf = '\0';
-  }
-  smartlist_add(chunks, tor_strdup(buf));
+
   log_notice(LD_CIRC, "Computed bandwidth weights for %s with v9: "
              "G="I64_FORMAT" M="I64_FORMAT" E="I64_FORMAT" D="I64_FORMAT
              " T="I64_FORMAT,
@@ -1475,7 +1457,6 @@ networkstatus_compute_consensus(smartlist_t *votes,
   chunks = smartlist_create();
 
   {
-    char *buf=NULL;
     char va_buf[ISO_TIME_LEN+1], fu_buf[ISO_TIME_LEN+1],
       vu_buf[ISO_TIME_LEN+1];
     char *flaglist;
@@ -1484,20 +1465,17 @@ networkstatus_compute_consensus(smartlist_t *votes,
     format_iso_time(vu_buf, valid_until);
     flaglist = smartlist_join_strings(flags, " ", 0, NULL);
 
-    tor_asprintf(&buf, "network-status-version 3%s%s\n"
+    smartlist_add_asprintf(chunks, "network-status-version 3%s%s\n"
                  "vote-status consensus\n",
                  flavor == FLAV_NS ? "" : " ",
                  flavor == FLAV_NS ? "" : flavor_name);
 
-    smartlist_add(chunks, buf);
-
     if (consensus_method >= 2) {
-      tor_asprintf(&buf, "consensus-method %d\n",
+      smartlist_add_asprintf(chunks, "consensus-method %d\n",
                    consensus_method);
-      smartlist_add(chunks, buf);
     }
 
-    tor_asprintf(&buf,
+    smartlist_add_asprintf(chunks,
                  "valid-after %s\n"
                  "fresh-until %s\n"
                  "valid-until %s\n"
@@ -1508,7 +1486,6 @@ networkstatus_compute_consensus(smartlist_t *votes,
                  va_buf, fu_buf, vu_buf,
                  vote_seconds, dist_seconds,
                  client_versions, server_versions, flaglist);
-    smartlist_add(chunks, buf);
 
     tor_free(flaglist);
   }
@@ -1550,7 +1527,6 @@ networkstatus_compute_consensus(smartlist_t *votes,
       char votedigest[HEX_DIGEST_LEN+1];
       networkstatus_t *v = e->v;
       networkstatus_voter_info_t *voter = get_voter(v);
-      char *buf = NULL;
 
       if (e->is_legacy)
         tor_assert(consensus_method >= 2);
@@ -1559,20 +1535,18 @@ networkstatus_compute_consensus(smartlist_t *votes,
       base16_encode(votedigest, sizeof(votedigest), voter->vote_digest,
                     DIGEST_LEN);
 
-      tor_asprintf(&buf,
+      smartlist_add_asprintf(chunks,
                    "dir-source %s%s %s %s %s %d %d\n",
                    voter->nickname, e->is_legacy ? "-legacy" : "",
                    fingerprint, voter->address, fmt_addr32(voter->addr),
                    voter->dir_port,
                    voter->or_port);
-      smartlist_add(chunks, buf);
       if (! e->is_legacy) {
-        tor_asprintf(&buf,
+        smartlist_add_asprintf(chunks,
                      "contact %s\n"
                      "vote-digest %s\n",
                      voter->contact,
                      votedigest);
-        smartlist_add(chunks, buf);
       }
     } SMARTLIST_FOREACH_END(e);
     SMARTLIST_FOREACH(dir_sources, dir_src_ent_t *, e, tor_free(e));
@@ -1709,7 +1683,6 @@ networkstatus_compute_consensus(smartlist_t *votes,
       int naming_conflict = 0;
       int n_listing = 0;
       int i;
-      char *buf=NULL;
       char microdesc_digest[DIGEST256_LEN];
 
       /* Of the next-to-be-considered digest in each voter, which is first? */
@@ -1977,10 +1950,9 @@ networkstatus_compute_consensus(smartlist_t *votes,
       /*     Now an m line, if applicable. */
       if (flavor == FLAV_MICRODESC &&
           !tor_digest256_is_zero(microdesc_digest)) {
-        char m[BASE64_DIGEST256_LEN+1], *cp;
+        char m[BASE64_DIGEST256_LEN+1];
         digest256_to_base64(m, microdesc_digest);
-        tor_asprintf(&cp, "m %s\n", m);
-        smartlist_add(chunks, cp);
+        smartlist_add_asprintf(chunks, "m %s\n", m);
       }
       /*     Next line is all flags.  The "\n" is missing. */
       smartlist_add(chunks,
@@ -1993,15 +1965,12 @@ networkstatus_compute_consensus(smartlist_t *votes,
       smartlist_add(chunks, tor_strdup("\n"));
       /*     Now the weight line. */
       if (rs_out.has_bandwidth) {
-        char *cp=NULL;
-        tor_asprintf(&cp, "w Bandwidth=%d\n", rs_out.bandwidth);
-        smartlist_add(chunks, cp);
+        smartlist_add_asprintf(chunks, "w Bandwidth=%d\n", rs_out.bandwidth);
       }
 
       /*     Now the exitpolicy summary line. */
       if (rs_out.has_exitsummary && flavor == FLAV_NS) {
-        tor_asprintf(&buf, "p %s\n", rs_out.exitsummary);
-        smartlist_add(chunks, buf);
+        smartlist_add_asprintf(chunks, "p %s\n", rs_out.exitsummary);
       }
 
       /* And the loop is over and we move on to the next router */
@@ -2083,7 +2052,6 @@ networkstatus_compute_consensus(smartlist_t *votes,
     size_t digest_len =
       flavor == FLAV_NS ? DIGEST_LEN : DIGEST256_LEN;
     const char *algname = crypto_digest_algorithm_get_name(digest_alg);
-    char *buf = NULL;
     char sigbuf[4096];
 
     smartlist_add(chunks, tor_strdup("directory-signature "));
@@ -2097,14 +2065,13 @@ networkstatus_compute_consensus(smartlist_t *votes,
 
     /* add the junk that will go at the end of the line. */
     if (flavor == FLAV_NS) {
-      tor_asprintf(&buf, "%s %s\n", fingerprint,
+      smartlist_add_asprintf(chunks, "%s %s\n", fingerprint,
                    signing_key_fingerprint);
     } else {
-      tor_asprintf(&buf, "%s %s %s\n",
+      smartlist_add_asprintf(chunks, "%s %s %s\n",
                    algname, fingerprint,
                    signing_key_fingerprint);
     }
-    smartlist_add(chunks, buf);
     /* And the signature. */
     sigbuf[0] = '\0';
     if (router_append_dirobj_signature(sigbuf, sizeof(sigbuf),
@@ -2122,14 +2089,13 @@ networkstatus_compute_consensus(smartlist_t *votes,
       crypto_pk_get_fingerprint(legacy_signing_key,
                                 signing_key_fingerprint, 0);
       if (flavor == FLAV_NS) {
-        tor_asprintf(&buf, "%s %s\n", fingerprint,
+        smartlist_add_asprintf(chunks, "%s %s\n", fingerprint,
                      signing_key_fingerprint);
       } else {
-        tor_asprintf(&buf, "%s %s %s\n",
+        smartlist_add_asprintf(chunks, "%s %s %s\n",
                      algname, fingerprint,
                      signing_key_fingerprint);
       }
-      smartlist_add(chunks, buf);
       sigbuf[0] = '\0';
       if (router_append_dirobj_signature(sigbuf, sizeof(sigbuf),
                                          digest, digest_len,
@@ -2334,20 +2300,19 @@ networkstatus_format_signatures(networkstatus_t *consensus,
       base16_encode(sk, sizeof(sk), sig->signing_key_digest, DIGEST_LEN);
       base16_encode(id, sizeof(id), sig->identity_digest, DIGEST_LEN);
       if (flavor == FLAV_NS) {
-        tor_snprintf(buf, sizeof(buf),
+        smartlist_add_asprintf(elements,
                      "%s %s %s\n-----BEGIN SIGNATURE-----\n",
                      keyword, id, sk);
       } else {
         const char *digest_name =
           crypto_digest_algorithm_get_name(sig->alg);
-        tor_snprintf(buf, sizeof(buf),
+        smartlist_add_asprintf(elements,
                      "%s%s%s %s %s %s\n-----BEGIN SIGNATURE-----\n",
                      keyword,
                      for_detached_signatures ? " " : "",
                      for_detached_signatures ? flavor_name : "",
                      digest_name, id, sk);
       }
-      smartlist_add(elements, tor_strdup(buf));
       base64_encode(buf, sizeof(buf), sig->signature, sig->signature_len);
       strlcat(buf, "-----END SIGNATURE-----\n", sizeof(buf));
       smartlist_add(elements, tor_strdup(buf));
@@ -2370,7 +2335,6 @@ char *
 networkstatus_get_detached_signatures(smartlist_t *consensuses)
 {
   smartlist_t *elements;
-  char buf[4096];
   char *result = NULL, *sigs = NULL;
   networkstatus_t *consensus_ns = NULL;
   tor_assert(consensuses);
@@ -2399,12 +2363,11 @@ networkstatus_get_detached_signatures(smartlist_t *consensuses)
     format_iso_time(fu_buf, consensus_ns->fresh_until);
     format_iso_time(vu_buf, consensus_ns->valid_until);
 
-    tor_snprintf(buf, sizeof(buf),
+    smartlist_add_asprintf(elements,
                  "consensus-digest %s\n"
                  "valid-after %s\n"
                  "fresh-until %s\n"
                  "valid-until %s\n", d, va_buf, fu_buf, vu_buf);
-    smartlist_add(elements, tor_strdup(buf));
   }
 
   /* Get all the digests for the non-FLAV_NS consensuses */
@@ -2423,9 +2386,8 @@ networkstatus_get_detached_signatures(smartlist_t *consensuses)
       if (tor_mem_is_zero(ns->digests.d[alg], DIGEST256_LEN))
         continue;
       base16_encode(d, sizeof(d), ns->digests.d[alg], DIGEST256_LEN);
-      tor_snprintf(buf, sizeof(buf), "additional-digest %s %s %s\n",
+      smartlist_add_asprintf(elements, "additional-digest %s %s %s\n",
                    flavor_name, alg_name, d);
-      smartlist_add(elements, tor_strdup(buf));
     }
   } SMARTLIST_FOREACH_END(ns);
 
diff --git a/src/or/geoip.c b/src/or/geoip.c
index 73194ae9c6..3e1ee5987f 100644
--- a/src/or/geoip.c
+++ b/src/or/geoip.c
@@ -856,9 +856,7 @@ geoip_get_client_history(geoip_client_action_t action)
   /* Build the result. */
   chunks = smartlist_create();
   SMARTLIST_FOREACH(entries, c_hist_t *, ch, {
-      char *buf=NULL;
-      tor_asprintf(&buf, "%s=%u", ch->country, ch->total);
-      smartlist_add(chunks, buf);
+      smartlist_add_asprintf(chunks, "%s=%u", ch->country, ch->total);
   });
   result = smartlist_join_strings(chunks, ",", 0, NULL);
  done:
@@ -907,10 +905,8 @@ geoip_get_request_history(geoip_client_action_t action)
 
   strings = smartlist_create();
   SMARTLIST_FOREACH(entries, c_hist_t *, ent, {
-      char *buf = NULL;
-      tor_asprintf(&buf, "%s=%u", ent->country, ent->total);
-      smartlist_add(strings, buf);
-    });
+      smartlist_add_asprintf(strings, "%s=%u", ent->country, ent->total);
+  });
   result = smartlist_join_strings(strings, ",", 0, NULL);
   SMARTLIST_FOREACH(strings, char *, cp, tor_free(cp));
   SMARTLIST_FOREACH(entries, c_hist_t *, ent, tor_free(ent));
diff --git a/src/or/hibernate.c b/src/or/hibernate.c
index 803f7f5764..917bd8205b 100644
--- a/src/or/hibernate.c
+++ b/src/or/hibernate.c
@@ -976,8 +976,7 @@ getinfo_helper_accounting(control_connection_t *conn,
     else
       *answer = tor_strdup("awake");
   } else if (!strcmp(question, "accounting/bytes")) {
-    *answer = tor_malloc(32);
-    tor_snprintf(*answer, 32, U64_FORMAT" "U64_FORMAT,
+    tor_asprintf(answer, U64_FORMAT" "U64_FORMAT,
                  U64_PRINTF_ARG(n_bytes_read_in_interval),
                  U64_PRINTF_ARG(n_bytes_written_in_interval));
   } else if (!strcmp(question, "accounting/bytes-left")) {
@@ -987,8 +986,7 @@ getinfo_helper_accounting(control_connection_t *conn,
       read_left = limit - n_bytes_read_in_interval;
     if (n_bytes_written_in_interval < limit)
       write_left = limit - n_bytes_written_in_interval;
-    *answer = tor_malloc(64);
-    tor_snprintf(*answer, 64, U64_FORMAT" "U64_FORMAT,
+    tor_asprintf(answer, U64_FORMAT" "U64_FORMAT,
                  U64_PRINTF_ARG(read_left), U64_PRINTF_ARG(write_left));
   } else if (!strcmp(question, "accounting/interval-start")) {
     *answer = tor_malloc(ISO_TIME_LEN+1);
diff --git a/src/or/networkstatus.c b/src/or/networkstatus.c
index a835e78b85..a4e8644f23 100644
--- a/src/or/networkstatus.c
+++ b/src/or/networkstatus.c
@@ -598,39 +598,38 @@ networkstatus_check_consensus_signature(networkstatus_t *consensus,
                  hex_str(ds->v3_identity_digest, DIGEST_LEN));
       });
     {
+      char *joined;
       smartlist_t *sl = smartlist_create();
-      char *cp;
       char *tmp = smartlist_join_strings(list_good, " ", 0, NULL);
-      tor_asprintf(&cp, "A consensus needs %d good signatures from recognized "
+      smartlist_add_asprintf(sl,
+                   "A consensus needs %d good signatures from recognized "
                    "authorities for us to accept it. This one has %d (%s).",
                    n_required, n_good, tmp);
       tor_free(tmp);
-      smartlist_add(sl,cp);
       if (n_no_signature) {
         tmp = smartlist_join_strings(list_no_signature, " ", 0, NULL);
-        tor_asprintf(&cp, "%d (%s) of the authorities we know didn't sign it.",
+        smartlist_add_asprintf(sl,
+                     "%d (%s) of the authorities we know didn't sign it.",
                      n_no_signature, tmp);
         tor_free(tmp);
-        smartlist_add(sl,cp);
       }
       if (n_unknown) {
-        tor_asprintf(&cp, "It has %d signatures from authorities we don't "
+        smartlist_add_asprintf(sl,
+                      "It has %d signatures from authorities we don't "
                       "recognize.", n_unknown);
-        smartlist_add(sl,cp);
       }
       if (n_bad) {
-        tor_asprintf(&cp, "%d of the signatures on it didn't verify "
+        smartlist_add_asprintf(sl, "%d of the signatures on it didn't verify "
                       "correctly.", n_bad);
-        smartlist_add(sl,cp);
       }
       if (n_missing_key) {
-        tor_asprintf(&cp, "We were unable to check %d of the signatures, "
+        smartlist_add_asprintf(sl,
+                      "We were unable to check %d of the signatures, "
                       "because we were missing the keys.", n_missing_key);
-        smartlist_add(sl,cp);
       }
-      cp = smartlist_join_strings(sl, " ", 0, NULL);
-      log(severity, LD_DIR, "%s", cp);
-      tor_free(cp);
+      joined = smartlist_join_strings(sl, " ", 0, NULL);
+      log(severity, LD_DIR, "%s", joined);
+      tor_free(joined);
       SMARTLIST_FOREACH(sl, char *, c, tor_free(c));
       smartlist_free(sl);
     }
@@ -2160,9 +2159,8 @@ networkstatus_dump_bridge_status_to_file(time_t now)
 {
   char *status = networkstatus_getinfo_by_purpose("bridge", now);
   const or_options_t *options = get_options();
-  size_t len = strlen(options->DataDirectory) + 32;
-  char *fname = tor_malloc(len);
-  tor_snprintf(fname, len, "%s"PATH_SEPARATOR"networkstatus-bridges",
+  char *fname = NULL;
+  tor_asprintf(&fname, "%s"PATH_SEPARATOR"networkstatus-bridges",
                options->DataDirectory);
   write_str_to_file(fname,status,0);
   tor_free(fname);
diff --git a/src/or/ntmain.c b/src/or/ntmain.c
index 8d03ea8087..da19573a46 100644
--- a/src/or/ntmain.c
+++ b/src/or/ntmain.c
@@ -456,9 +456,9 @@ nt_service_command_line(int *using_default_torrc)
 {
   TCHAR tor_exe[MAX_PATH+1];
   char tor_exe_ascii[MAX_PATH+1];
-  char *command, *options=NULL;
+  char *command=NULL, *options=NULL;
   smartlist_t *sl;
-  int i, cmdlen;
+  int i;
   *using_default_torrc = 1;
 
   /* Get the location of tor.exe */
@@ -487,21 +487,13 @@ nt_service_command_line(int *using_default_torrc)
   strlcpy(tor_exe_ascii, tor_exe, sizeof(tor_exe_ascii));
 #endif
 
-  /* Allocate a string for the NT service command line */
-  cmdlen = strlen(tor_exe_ascii) + (options?strlen(options):0) + 32;
-  command = tor_malloc(cmdlen);
-
+  /* Allocate a string for the NT service command line and */
   /* Format the service command */
   if (options) {
-    if (tor_snprintf(command, cmdlen, "\"%s\" --nt-service \"%s\"",
-                     tor_exe_ascii, options)<0) {
-      tor_free(command); /* sets command to NULL. */
-    }
+    tor_asprintf(&command, "\"%s\" --nt-service \"%s\"",
+                 tor_exe_ascii, options);
   } else { /* ! options */
-    if (tor_snprintf(command, cmdlen, "\"%s\" --nt-service",
-                     tor_exe_ascii)<0) {
-      tor_free(command); /* sets command to NULL. */
-    }
+    tor_asprintf(&command, "\"%s\" --nt-service", tor_exe_ascii);
   }
 
   tor_free(options);
diff --git a/src/or/policies.c b/src/or/policies.c
index 34cb64bd81..53cdf48403 100644
--- a/src/or/policies.c
+++ b/src/or/policies.c
@@ -1218,7 +1218,7 @@ policy_summarize(smartlist_t *policy)
   smartlist_t *summary = policy_summary_create();
   smartlist_t *accepts, *rejects;
   int i, last, start_prt;
-  size_t accepts_len, rejects_len, shorter_len, final_size;
+  size_t accepts_len, rejects_len;
   char *accepts_str = NULL, *rejects_str = NULL, *shorter_str, *result;
   const char *prefix;
 
@@ -1290,21 +1290,15 @@ policy_summarize(smartlist_t *policy)
     tor_assert(*c == ',');
     *c = '\0';
 
-    shorter_len = strlen(shorter_str);
   } else if (rejects_len < accepts_len) {
     shorter_str = rejects_str;
-    shorter_len = rejects_len;
     prefix = "reject";
   } else {
     shorter_str = accepts_str;
-    shorter_len = accepts_len;
     prefix = "accept";
   }
 
-  final_size = strlen(prefix)+1+shorter_len+1;
-  tor_assert(final_size <= MAX_EXITPOLICY_SUMMARY_LEN+1);
-  result = tor_malloc(final_size);
-  tor_snprintf(result, final_size, "%s %s", prefix, shorter_str);
+  tor_asprintf(&result, "%s %s", prefix, shorter_str);
 
  cleanup:
   /* cleanup */
diff --git a/src/or/rephist.c b/src/or/rephist.c
index 6bbb93b821..4129fe2bbd 100644
--- a/src/or/rephist.c
+++ b/src/or/rephist.c
@@ -941,7 +941,6 @@ rep_hist_get_router_stability_doc(time_t now)
   DIGESTMAP_FOREACH(history_map, id, or_history_t *, hist) {
     const node_t *node;
     char dbuf[BASE64_DIGEST_LEN+1];
-    char header_buf[512];
     char *info;
     digest_to_base64(dbuf, id);
     node = node_get_by_id(id);
@@ -954,7 +953,7 @@ rep_hist_get_router_stability_doc(time_t now)
         format_iso_time(tbuf, published);
       else
         strlcpy(tbuf, "???", sizeof(tbuf));
-      tor_snprintf(header_buf, sizeof(header_buf),
+      smartlist_add_asprintf(chunks,
                    "router %s %s %s\n"
                    "published %s\n"
                    "relevant-flags %s%s%s\n"
@@ -966,10 +965,9 @@ rep_hist_get_router_stability_doc(time_t now)
                    node->ri && node->ri->is_hibernating ? "Hibernating " : "",
                    node_get_declared_uptime(node));
     } else {
-      tor_snprintf(header_buf, sizeof(header_buf),
+      smartlist_add_asprintf(chunks,
                    "router %s {no descriptor}\n", dbuf);
     }
-    smartlist_add(chunks, tor_strdup(header_buf));
     info = rep_hist_format_router_status(hist, now);
     if (info)
       smartlist_add(chunks, info);
@@ -1588,7 +1586,6 @@ rep_hist_update_bwhist_state_section(or_state_t *state,
                                      time_t *s_begins,
                                      int *s_interval)
 {
-  char *cp;
   int i,j;
   uint64_t maxval;
 
@@ -1626,17 +1623,17 @@ rep_hist_update_bwhist_state_section(or_state_t *state,
   for (j=0; j < b->num_maxes_set; ++j,++i) {
     if (i >= NUM_TOTALS)
       i = 0;
-    tor_asprintf(&cp, U64_FORMAT, U64_PRINTF_ARG(b->totals[i] & ~0x3ff));
-    smartlist_add(*s_values, cp);
+    smartlist_add_asprintf(*s_values, U64_FORMAT,
+                           U64_PRINTF_ARG(b->totals[i] & ~0x3ff));
     maxval = b->maxima[i] / NUM_SECS_ROLLING_MEASURE;
-    tor_asprintf(&cp, U64_FORMAT, U64_PRINTF_ARG(maxval & ~0x3ff));
-    smartlist_add(*s_maxima, cp);
+    smartlist_add_asprintf(*s_maxima, U64_FORMAT,
+                           U64_PRINTF_ARG(maxval & ~0x3ff));
   }
-  tor_asprintf(&cp, U64_FORMAT, U64_PRINTF_ARG(b->total_in_period & ~0x3ff));
-  smartlist_add(*s_values, cp);
+  smartlist_add_asprintf(*s_values, U64_FORMAT,
+                         U64_PRINTF_ARG(b->total_in_period & ~0x3ff));
   maxval = b->max_total / NUM_SECS_ROLLING_MEASURE;
-  tor_asprintf(&cp, U64_FORMAT, U64_PRINTF_ARG(maxval & ~0x3ff));
-  smartlist_add(*s_maxima, cp);
+  smartlist_add_asprintf(*s_maxima, U64_FORMAT,
+                         U64_PRINTF_ARG(maxval & ~0x3ff));
 }
 
 /** Update <b>state</b> with the newest bandwidth history. Done before
@@ -2125,7 +2122,6 @@ rep_hist_format_exit_stats(time_t now)
   uint64_t cur_bytes = 0, other_read = 0, other_written = 0,
            total_read = 0, total_written = 0;
   uint32_t total_streams = 0, other_streams = 0;
-  char *buf;
   smartlist_t *written_strings, *read_strings, *streams_strings;
   char *written_string, *read_string, *streams_string;
   char t[ISO_TIME_LEN+1];
@@ -2204,9 +2200,8 @@ rep_hist_format_exit_stats(time_t now)
                      exit_bytes_written[cur_port],
                      EXIT_STATS_ROUND_UP_BYTES);
       num /= 1024;
-      buf = NULL;
-      tor_asprintf(&buf, "%d="U64_FORMAT, cur_port, U64_PRINTF_ARG(num));
-      smartlist_add(written_strings, buf);
+      smartlist_add_asprintf(written_strings, "%d="U64_FORMAT,
+                             cur_port, U64_PRINTF_ARG(num));
       other_written -= exit_bytes_written[cur_port];
     }
     if (exit_bytes_read[cur_port] > 0) {
@@ -2214,18 +2209,15 @@ rep_hist_format_exit_stats(time_t now)
                      exit_bytes_read[cur_port],
                      EXIT_STATS_ROUND_UP_BYTES);
       num /= 1024;
-      buf = NULL;
-      tor_asprintf(&buf, "%d="U64_FORMAT, cur_port, U64_PRINTF_ARG(num));
-      smartlist_add(read_strings, buf);
+      smartlist_add_asprintf(read_strings, "%d="U64_FORMAT,
+                             cur_port, U64_PRINTF_ARG(num));
       other_read -= exit_bytes_read[cur_port];
     }
     if (exit_streams[cur_port] > 0) {
       uint32_t num = round_uint32_to_next_multiple_of(
                      exit_streams[cur_port],
                      EXIT_STATS_ROUND_UP_STREAMS);
-      buf = NULL;
-      tor_asprintf(&buf, "%d=%u", cur_port, num);
-      smartlist_add(streams_strings, buf);
+      smartlist_add_asprintf(streams_strings, "%d=%u", cur_port, num);
       other_streams -= exit_streams[cur_port];
     }
   }
@@ -2234,20 +2226,16 @@ rep_hist_format_exit_stats(time_t now)
   other_written = round_uint64_to_next_multiple_of(other_written,
                   EXIT_STATS_ROUND_UP_BYTES);
   other_written /= 1024;
-  buf = NULL;
-  tor_asprintf(&buf, "other="U64_FORMAT, U64_PRINTF_ARG(other_written));
-  smartlist_add(written_strings, buf);
+  smartlist_add_asprintf(written_strings, "other="U64_FORMAT,
+                         U64_PRINTF_ARG(other_written));
   other_read = round_uint64_to_next_multiple_of(other_read,
                EXIT_STATS_ROUND_UP_BYTES);
   other_read /= 1024;
-  buf = NULL;
-  tor_asprintf(&buf, "other="U64_FORMAT, U64_PRINTF_ARG(other_read));
-  smartlist_add(read_strings, buf);
+  smartlist_add_asprintf(read_strings, "other="U64_FORMAT,
+                         U64_PRINTF_ARG(other_read));
   other_streams = round_uint32_to_next_multiple_of(other_streams,
                   EXIT_STATS_ROUND_UP_STREAMS);
-  buf = NULL;
-  tor_asprintf(&buf, "other=%u", other_streams);
-  smartlist_add(streams_strings, buf);
+  smartlist_add_asprintf(streams_strings, "other=%u", other_streams);
 
   /* Join all observations in single strings. */
   written_string = smartlist_join_strings(written_strings, ",", 0, NULL);
@@ -2468,7 +2456,6 @@ rep_hist_format_buffer_stats(time_t now)
   int processed_cells[SHARES], circs_in_share[SHARES],
       number_of_circuits, i;
   double queued_cells[SHARES], time_in_queue[SHARES];
-  char *buf = NULL;
   smartlist_t *processed_cells_strings, *queued_cells_strings,
               *time_in_queue_strings;
   char *processed_cells_string, *queued_cells_string,
@@ -2510,19 +2497,19 @@ rep_hist_format_buffer_stats(time_t now)
   queued_cells_strings = smartlist_create();
   time_in_queue_strings = smartlist_create();
   for (i = 0; i < SHARES; i++) {
-    tor_asprintf(&buf,"%d", !circs_in_share[i] ? 0 :
-                 processed_cells[i] / circs_in_share[i]);
-    smartlist_add(processed_cells_strings, buf);
+    smartlist_add_asprintf(processed_cells_strings,
+                           "%d", !circs_in_share[i] ? 0 :
+                              processed_cells[i] / circs_in_share[i]);
   }
   for (i = 0; i < SHARES; i++) {
-    tor_asprintf(&buf, "%.2f", circs_in_share[i] == 0 ? 0.0 :
-                 queued_cells[i] / (double) circs_in_share[i]);
-    smartlist_add(queued_cells_strings, buf);
+    smartlist_add_asprintf(queued_cells_strings, "%.2f",
+                           circs_in_share[i] == 0 ? 0.0 :
+                             queued_cells[i] / (double) circs_in_share[i]);
   }
   for (i = 0; i < SHARES; i++) {
-    tor_asprintf(&buf, "%.0f", circs_in_share[i] == 0 ? 0.0 :
-                 time_in_queue[i] / (double) circs_in_share[i]);
-    smartlist_add(time_in_queue_strings, buf);
+    smartlist_add_asprintf(time_in_queue_strings, "%.0f",
+                           circs_in_share[i] == 0 ? 0.0 :
+                             time_in_queue[i] / (double) circs_in_share[i]);
   }
 
   /* Join all observations in single strings. */
diff --git a/src/or/router.c b/src/or/router.c
index b2df3834fe..0339e682a8 100644
--- a/src/or/router.c
+++ b/src/or/router.c
@@ -1973,11 +1973,9 @@ router_dump_router_to_string(char *s, size_t maxlen, routerinfo_t *router,
   format_iso_time(published, router->cache_info.published_on);
 
   if (router->declared_family && smartlist_len(router->declared_family)) {
-    size_t n;
-    char *family = smartlist_join_strings(router->declared_family, " ", 0, &n);
-    n += strlen("family ") + 2; /* 1 for \n, 1 for \0. */
-    family_line = tor_malloc(n);
-    tor_snprintf(family_line, n, "family %s\n", family);
+    char *family = smartlist_join_strings(router->declared_family,
+                                          " ", 0, NULL);
+    tor_asprintf(&family_line, "family %s\n", family);
     tor_free(family);
   } else {
     family_line = tor_strdup("");
@@ -2267,9 +2265,7 @@ extrainfo_dump_to_string(char **s_out, extrainfo_t *extrainfo,
   smartlist_add(chunks, pre);
 
   if (geoip_is_loaded()) {
-    char *chunk=NULL;
-    tor_asprintf(&chunk, "geoip-db-digest %s\n", geoip_db_digest());
-    smartlist_add(chunks, chunk);
+    smartlist_add_asprintf(chunks, "geoip-db-digest %s\n", geoip_db_digest());
   }
 
   if (options->ExtraInfoStatistics && write_stats_to_extrainfo) {
diff --git a/src/or/routerlist.c b/src/or/routerlist.c
index 689df99c57..b81289e856 100644
--- a/src/or/routerlist.c
+++ b/src/or/routerlist.c
@@ -2408,8 +2408,6 @@ router_get_by_nickname(const char *nickname, int warn_if_unnamed)
       int any_unwarned = 0;
       SMARTLIST_FOREACH_BEGIN(routerlist->routers, routerinfo_t *, router) {
           routerstatus_t *rs;
-          char *desc;
-          size_t dlen;
           char fp[HEX_DIGEST_LEN+1];
           if (strcasecmp(router->nickname, nickname))
             continue;
@@ -2421,11 +2419,8 @@ router_get_by_nickname(const char *nickname, int warn_if_unnamed)
           }
           base16_encode(fp, sizeof(fp),
                         router->cache_info.identity_digest, DIGEST_LEN);
-          dlen = 32 + HEX_DIGEST_LEN + strlen(router->address);
-          desc = tor_malloc(dlen);
-          tor_snprintf(desc, dlen, "\"$%s\" for the one at %s:%d",
+          smartlist_add_asprintf(fps, "\"$%s\" for the one at %s:%d",
                        fp, router->address, router->or_port);
-          smartlist_add(fps, desc);
       } SMARTLIST_FOREACH_END(router);
       if (any_unwarned) {
         char *alternatives = smartlist_join_strings(fps, "; ",0,NULL);
@@ -4071,7 +4066,6 @@ add_trusted_dir_server(const char *nickname, const char *address,
   trusted_dir_server_t *ent;
   uint32_t a;
   char *hostname = NULL;
-  size_t dlen;
   if (!trusted_dir_servers)
     trusted_dir_servers = smartlist_create();
 
@@ -4104,13 +4098,11 @@ add_trusted_dir_server(const char *nickname, const char *address,
   if (v3_auth_digest && (type & V3_DIRINFO))
     memcpy(ent->v3_identity_digest, v3_auth_digest, DIGEST_LEN);
 
-  dlen = 64 + strlen(hostname) + (nickname?strlen(nickname):0);
-  ent->description = tor_malloc(dlen);
   if (nickname)
-    tor_snprintf(ent->description, dlen, "directory server \"%s\" at %s:%d",
+    tor_asprintf(&ent->description, "directory server \"%s\" at %s:%d",
                  nickname, hostname, (int)dir_port);
   else
-    tor_snprintf(ent->description, dlen, "directory server at %s:%d",
+    tor_asprintf(&ent->description, "directory server at %s:%d",
                  hostname, (int)dir_port);
 
   ent->fake_status.addr = ent->addr;
@@ -5333,7 +5325,6 @@ esc_router_info(const routerinfo_t *router)
 {
   static char *info=NULL;
   char *esc_contact, *esc_platform;
-  size_t len;
   tor_free(info);
 
   if (!router)
@@ -5342,10 +5333,7 @@ esc_router_info(const routerinfo_t *router)
   esc_contact = esc_for_log(router->contact_info);
   esc_platform = esc_for_log(router->platform);
 
-  len = strlen(esc_contact)+strlen(esc_platform)+32;
-  info = tor_malloc(len);
-  tor_snprintf(info, len, "Contact %s, Platform %s", esc_contact,
-               esc_platform);
+  tor_asprintf(&info, "Contact %s, Platform %s", esc_contact, esc_platform);
   tor_free(esc_contact);
   tor_free(esc_platform);
 
diff --git a/src/or/transports.c b/src/or/transports.c
index abf9d884f7..d8d2ff6aa6 100644
--- a/src/or/transports.c
+++ b/src/or/transports.c
@@ -918,7 +918,7 @@ parse_cmethod_line(const char *line, managed_proxy_t *mp)
 static char *
 get_bindaddr_for_proxy(const managed_proxy_t *mp)
 {
-  char *bindaddr = NULL;
+  char *bindaddr_result = NULL;
   char *bindaddr_tmp = NULL;
   smartlist_t *string_tmp = smartlist_create();
 
@@ -927,18 +927,17 @@ get_bindaddr_for_proxy(const managed_proxy_t *mp)
   SMARTLIST_FOREACH_BEGIN(mp->transports_to_launch, char *, t) {
     bindaddr_tmp = get_bindaddr_for_transport(t);
 
-    tor_asprintf(&bindaddr, "%s-%s", t, bindaddr_tmp);
-    smartlist_add(string_tmp, bindaddr);
+    smartlist_add_asprintf(string_tmp, "%s-%s", t, bindaddr_tmp);
 
     tor_free(bindaddr_tmp);
   } SMARTLIST_FOREACH_END(t);
 
-  bindaddr = smartlist_join_strings(string_tmp, ",", 0, NULL);
+  bindaddr_result = smartlist_join_strings(string_tmp, ",", 0, NULL);
 
   SMARTLIST_FOREACH(string_tmp, char *, t, tor_free(t));
   smartlist_free(string_tmp);
 
-  return bindaddr;
+  return bindaddr_result;
 }
 
 #ifdef MS_WINDOWS