Convert tincd path args to absolute paths

[tinc] / src / utils.c

diff --git a/src/utils.c b/src/utils.c
index c395169..5f40b8a 100644 (file)
--- a/src/utils.c
+++ b/src/utils.c
@@ -81,6 +81,57 @@ size_t bin2hex(const void *vsrc, char *dst, size_t length) {
        return length * 2;
 }
 
+char *absolute_path(const char *path) {
+#ifdef HAVE_WINDOWS
+       // Works for nonexistent paths
+       return _fullpath(NULL, path, 0);
+#else
+
+       if(!path || !*path) {
+               return NULL;
+       }
+
+       // If an absolute path was passed, return its copy
+       if(*path == '/') {
+               return xstrdup(path);
+       }
+
+       // Try using realpath. If it fails for any reason
+       // other than that the file was not found, bail out.
+       char *abs = realpath(path, NULL);
+
+       if(abs || errno != ENOENT) {
+               return abs;
+       }
+
+       // Since the file does not exist, we're forced to use a fallback.
+       // Get current working directory and concatenate it with the argument.
+       char cwd[PATH_MAX];
+
+       if(!getcwd(cwd, sizeof(cwd))) {
+               return NULL;
+       }
+
+       // Remove trailing slash if present since we'll be adding our own
+       size_t cwdlen = strlen(cwd);
+
+       if(cwdlen && cwd[cwdlen - 1] == '/') {
+               cwd[cwdlen - 1] = '\0';
+       }
+
+       // We don't do any normalization because it's complicated, and the payoff is small.
+       // If user passed something like '.././../foo' — that's their choice; fopen works either way.
+       xasprintf(&abs, "%s/%s", cwd, path);
+
+       if(strlen(abs) >= PATH_MAX) {
+               free(abs);
+               abs = NULL;
+       }
+
+       return abs;
+#endif
+}
+
 size_t b64decode_tinc(const char *src, void *dst, size_t length) {
        size_t i;
        uint32_t triplet = 0;