Add a function to pull off the final component of a path

2 files changed, 36 insertions, 0 deletions

diff --git a/src/common/compat.c b/src/common/compat.c
index ea7f9d7efc..3c5e9385e2 100644
--- a/src/common/compat.c
+++ b/src/common/compat.c
@@ -1467,6 +1467,40 @@ get_user_homedir(const char *username)
 }
 #endif
 
+/** Modify <b>fname</b> to contain the name of the directory */
+int
+get_parent_directory(char *fname)
+{
+  char *cp;
+  int at_end = 1;
+  tor_assert(fname);
+#ifdef MS_WINDOWS
+  /* If we start with, say, c:, then don't consider that the start of the path
+   */
+  if (fname[0] && fname[1] == ':') {
+    fname += 2;
+  }
+#endif
+  /* Now we want to remove the final character that */
+  cp = fname + strlen(fname);
+  at_end = 1;
+  while (--cp > fname) {
+    int is_sep = (*cp == '/'
+#ifdef MS_WINDOWS
+                  || *cp == '\\'
+#endif
+                  );
+    if (is_sep) {
+      *cp = '\0';
+      if (! at_end)
+        return 0;
+    } else {
+      at_end = 0;
+    }
+  }
+  return -1;
+}
+
 /** Set *addr to the IP address (in dotted-quad notation) stored in c.
  * Return 1 on success, 0 if c is badly formatted.  (Like inet_aton(c,addr),
  * but works on Windows and Solaris.)
diff --git a/src/common/compat.h b/src/common/compat.h
index af795ffba9..eff51ab30c 100644
--- a/src/common/compat.h
+++ b/src/common/compat.h
@@ -552,6 +552,8 @@ int switch_id(const char *user);
 char *get_user_homedir(const char *username);
 #endif
 
+int get_parent_directory(char *fname);
+
 int spawn_func(void (*func)(void *), void *data);
 void spawn_exit(void) ATTR_NORETURN;