diff options
Diffstat (limited to 'path.c')
| -rw-r--r-- | path.c | 53 |
1 files changed, 53 insertions, 0 deletions
@@ -357,3 +357,56 @@ const char *make_absolute_path(const char *path) return buf; } + +/* + * path = absolute path + * buf = buffer of at least max(2, strlen(path)+1) bytes + * It is okay if buf == path, but they should not overlap otherwise. + * + * Performs the following normalizations on path, storing the result in buf: + * - Removes trailing slashes. + * - Removes empty components. + * - Removes "." components. + * - Removes ".." components, and the components the precede them. + * "" and paths that contain only slashes are normalized to "/". + * Returns the length of the output. + * + * Note that this function is purely textual. It does not follow symlinks, + * verify the existence of the path, or make any system calls. + */ +int normalize_absolute_path(char *buf, const char *path) +{ + const char *comp_start = path, *comp_end = path; + char *dst = buf; + int comp_len; + assert(buf); + assert(path); + + while (*comp_start) { + assert(*comp_start == '/'); + while (*++comp_end && *comp_end != '/') + ; /* nothing */ + comp_len = comp_end - comp_start; + + if (!strncmp("/", comp_start, comp_len) || + !strncmp("/.", comp_start, comp_len)) + goto next; + + if (!strncmp("/..", comp_start, comp_len)) { + while (dst > buf && *--dst != '/') + ; /* nothing */ + goto next; + } + + memcpy(dst, comp_start, comp_len); + dst += comp_len; + next: + comp_start = comp_end; + } + + if (dst == buf) + *dst++ = '/'; + + *dst = '\0'; + return dst - buf; +} |