Rename tm_cvt to time_to_tm

1 files changed, 200 insertions, 0 deletions

diff --git a/src/lib/wallclock/time_to_tm.c b/src/lib/wallclock/time_to_tm.c
new file mode 100644
index 0000000000..6543b97e37
--- /dev/null
+++ b/src/lib/wallclock/time_to_tm.c
@@ -0,0 +1,200 @@
+/* Copyright (c) 2003-2004, Roger Dingledine
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2018, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+/**
+ * \file time_to_tm.c
+ * \brief Convert to struct tm, portably.
+ **/
+
+#include "orconfig.h"
+#include "lib/cc/torint.h"
+#include "lib/cc/compat_compiler.h"
+#include "lib/wallclock/time_to_tm.h"
+#include "lib/string/printf.h"
+#include "lib/err/torerr.h"
+
+#include <errno.h>
+#include <time.h>
+#include <string.h>
+#include <stdlib.h>
+
+#if !defined(_WIN32)
+/** Defined iff we need to add locks when defining fake versions of reentrant
+ * versions of time-related functions. */
+#define TIME_FNS_NEED_LOCKS
+#endif
+
+/** Helper: Deal with confused or out-of-bounds values from localtime_r and
+ * friends.  (On some platforms, they can give out-of-bounds values or can
+ * return NULL.)  If <b>islocal</b>, this is a localtime result; otherwise
+ * it's from gmtime.  The function returns <b>r</b>, when given <b>timep</b>
+ * as its input. If we need to store new results, store them in
+ * <b>resultbuf</b>. */
+static struct tm *
+correct_tm(int islocal, const time_t *timep, struct tm *resultbuf,
+           struct tm *r, char **err_out)
+{
+  const char *outcome;
+
+  if (PREDICT_LIKELY(r)) {
+    /* We can't strftime dates after 9999 CE, and we want to avoid dates
+     * before 1 CE (avoiding the year 0 issue and negative years). */
+    if (r->tm_year > 8099) {
+      r->tm_year = 8099;
+      r->tm_mon = 11;
+      r->tm_mday = 31;
+      r->tm_yday = 364;
+      r->tm_wday = 6;
+      r->tm_hour = 23;
+      r->tm_min = 59;
+      r->tm_sec = 59;
+    } else if (r->tm_year < (1-1900)) {
+      r->tm_year = (1-1900);
+      r->tm_mon = 0;
+      r->tm_mday = 1;
+      r->tm_yday = 0;
+      r->tm_wday = 0;
+      r->tm_hour = 0;
+      r->tm_min = 0;
+      r->tm_sec = 0;
+    }
+    return r;
+  }
+
+  /* If we get here, gmtime or localtime returned NULL. It might have done
+   * this because of overrun or underrun, or it might have done it because of
+   * some other weird issue. */
+  if (timep) {
+    if (*timep < 0) {
+      r = resultbuf;
+      r->tm_year = 70; /* 1970 CE */
+      r->tm_mon = 0;
+      r->tm_mday = 1;
+      r->tm_yday = 0;
+      r->tm_wday = 0;
+      r->tm_hour = 0;
+      r->tm_min = 0 ;
+      r->tm_sec = 0;
+      outcome = "Rounding up to 1970";
+      goto done;
+    } else if (*timep >= INT32_MAX) {
+      /* Rounding down to INT32_MAX isn't so great, but keep in mind that we
+       * only do it if gmtime/localtime tells us NULL. */
+      r = resultbuf;
+      r->tm_year = 137; /* 2037 CE */
+      r->tm_mon = 11;
+      r->tm_mday = 31;
+      r->tm_yday = 364;
+      r->tm_wday = 6;
+      r->tm_hour = 23;
+      r->tm_min = 59;
+      r->tm_sec = 59;
+      outcome = "Rounding down to 2037";
+      goto done;
+    }
+  }
+
+  /* If we get here, then gmtime/localtime failed without getting an extreme
+   * value for *timep */
+  /* LCOV_EXCL_START */
+  r = resultbuf;
+  memset(resultbuf, 0, sizeof(struct tm));
+  outcome="can't recover";
+  /* LCOV_EXCL_STOP */
+ done:
+  if (err_out) {
+    tor_asprintf(err_out, "%s(%"PRId64") failed with error %s: %s",
+                 islocal?"localtime":"gmtime",
+                 timep?((int64_t)*timep):0,
+                 strerror(errno),
+                 outcome);
+  }
+  return r;
+}
+
+/** @{ */
+/** As localtime_r, but defined for platforms that don't have it:
+ *
+ * Convert *<b>timep</b> to a struct tm in local time, and store the value in
+ * *<b>result</b>.  Return the result on success, or NULL on failure.
+ */
+#ifdef HAVE_LOCALTIME_R
+struct tm *
+tor_localtime_r_msg(const time_t *timep, struct tm *result, char **err_out)
+{
+  struct tm *r;
+  r = localtime_r(timep, result);
+  return correct_tm(1, timep, result, r, err_out);
+}
+#elif defined(TIME_FNS_NEED_LOCKS)
+struct tm *
+tor_localtime_r_msg(const time_t *timep, struct tm *result, char **err_out)
+{
+  struct tm *r;
+  static tor_mutex_t *m=NULL;
+  if (!m) { m=tor_mutex_new(); }
+  raw_assert(result);
+  tor_mutex_acquire(m);
+  r = localtime(timep);
+  if (r)
+    memcpy(result, r, sizeof(struct tm));
+  tor_mutex_release(m);
+  return correct_tm(1, timep, result, r, err_out);
+}
+#else
+struct tm *
+tor_localtime_r_msg(const time_t *timep, struct tm *result, char **err_out)
+{
+  struct tm *r;
+  raw_assert(result);
+  r = localtime(timep);
+  if (r)
+    memcpy(result, r, sizeof(struct tm));
+  return correct_tm(1, timep, result, r, err_out);
+}
+#endif /* defined(HAVE_LOCALTIME_R) || ... */
+/** @} */
+
+/** @{ */
+/** As gmtime_r, but defined for platforms that don't have it:
+ *
+ * Convert *<b>timep</b> to a struct tm in UTC, and store the value in
+ * *<b>result</b>.  Return the result on success, or NULL on failure.
+ */
+#ifdef HAVE_GMTIME_R
+struct tm *
+tor_gmtime_r_msg(const time_t *timep, struct tm *result, char **err_out)
+{
+  struct tm *r;
+  r = gmtime_r(timep, result);
+  return correct_tm(0, timep, result, r, err_out);
+}
+#elif defined(TIME_FNS_NEED_LOCKS)
+struct tm *
+tor_gmtime_r_msg(const time_t *timep, struct tm *result, char **err_out)
+{
+  struct tm *r;
+  static tor_mutex_t *m=NULL;
+  if (!m) { m=tor_mutex_new(); }
+  raw_assert(result);
+  tor_mutex_acquire(m);
+  r = gmtime(timep);
+  if (r)
+    memcpy(result, r, sizeof(struct tm));
+  tor_mutex_release(m);
+  return correct_tm(0, timep, result, r, err_out);
+}
+#else
+struct tm *
+tor_gmtime_r_msg(const time_t *timep, struct tm *result, char **err_out)
+{
+  struct tm *r;
+  raw_assert(result);
+  r = gmtime(timep);
+  if (r)
+    memcpy(result, r, sizeof(struct tm));
+  return correct_tm(0, timep, result, r, err_out);
+}
+#endif /* defined(HAVE_GMTIME_R) || ... */