diff options
Diffstat (limited to 'path.c')
| -rw-r--r-- | path.c | 666 |
1 files changed, 666 insertions, 0 deletions
diff --git a/path.c b/path.c new file mode 100644 index 0000000000..b6f71d1086 --- /dev/null +++ b/path.c @@ -0,0 +1,666 @@ +/* + * I'm tired of doing "vsnprintf()" etc just to open a + * file, so here's a "return static buffer with printf" + * interface for paths. + * + * It's obviously not thread-safe. Sue me. But it's quite + * useful for doing things like + * + * f = open(mkpath("%s/%s.git", base, name), O_RDONLY); + * + * which is what it's designed for. + */ +#include "cache.h" +#include "strbuf.h" + +static char bad_path[] = "/bad-path/"; + +static char *get_pathname(void) +{ + static char pathname_array[4][PATH_MAX]; + static int index; + return pathname_array[3 & ++index]; +} + +static char *cleanup_path(char *path) +{ + /* Clean it up */ + if (!memcmp(path, "./", 2)) { + path += 2; + while (*path == '/') + path++; + } + return path; +} + +char *mksnpath(char *buf, size_t n, const char *fmt, ...) +{ + va_list args; + unsigned len; + + va_start(args, fmt); + len = vsnprintf(buf, n, fmt, args); + va_end(args); + if (len >= n) { + strlcpy(buf, bad_path, n); + return buf; + } + return cleanup_path(buf); +} + +static char *git_vsnpath(char *buf, size_t n, const char *fmt, va_list args) +{ + const char *git_dir = get_git_dir(); + size_t len; + + len = strlen(git_dir); + if (n < len + 1) + goto bad; + memcpy(buf, git_dir, len); + if (len && !is_dir_sep(git_dir[len-1])) + buf[len++] = '/'; + len += vsnprintf(buf + len, n - len, fmt, args); + if (len >= n) + goto bad; + return cleanup_path(buf); +bad: + strlcpy(buf, bad_path, n); + return buf; +} + +char *git_snpath(char *buf, size_t n, const char *fmt, ...) +{ + va_list args; + va_start(args, fmt); + (void)git_vsnpath(buf, n, fmt, args); + va_end(args); + return buf; +} + +char *git_pathdup(const char *fmt, ...) +{ + char path[PATH_MAX]; + va_list args; + va_start(args, fmt); + (void)git_vsnpath(path, sizeof(path), fmt, args); + va_end(args); + return xstrdup(path); +} + +char *mkpath(const char *fmt, ...) +{ + va_list args; + unsigned len; + char *pathname = get_pathname(); + + va_start(args, fmt); + len = vsnprintf(pathname, PATH_MAX, fmt, args); + va_end(args); + if (len >= PATH_MAX) + return bad_path; + return cleanup_path(pathname); +} + +char *git_path(const char *fmt, ...) +{ + const char *git_dir = get_git_dir(); + char *pathname = get_pathname(); + va_list args; + unsigned len; + + len = strlen(git_dir); + if (len > PATH_MAX-100) + return bad_path; + memcpy(pathname, git_dir, len); + if (len && git_dir[len-1] != '/') + pathname[len++] = '/'; + va_start(args, fmt); + len += vsnprintf(pathname + len, PATH_MAX - len, fmt, args); + va_end(args); + if (len >= PATH_MAX) + return bad_path; + return cleanup_path(pathname); +} + +char *git_path_submodule(const char *path, const char *fmt, ...) +{ + char *pathname = get_pathname(); + struct strbuf buf = STRBUF_INIT; + const char *git_dir; + va_list args; + unsigned len; + + len = strlen(path); + if (len > PATH_MAX-100) + return bad_path; + + strbuf_addstr(&buf, path); + if (len && path[len-1] != '/') + strbuf_addch(&buf, '/'); + strbuf_addstr(&buf, ".git"); + + git_dir = read_gitfile(buf.buf); + if (git_dir) { + strbuf_reset(&buf); + strbuf_addstr(&buf, git_dir); + } + strbuf_addch(&buf, '/'); + + if (buf.len >= PATH_MAX) + return bad_path; + memcpy(pathname, buf.buf, buf.len + 1); + + strbuf_release(&buf); + len = strlen(pathname); + + va_start(args, fmt); + len += vsnprintf(pathname + len, PATH_MAX - len, fmt, args); + va_end(args); + if (len >= PATH_MAX) + return bad_path; + return cleanup_path(pathname); +} + +int validate_headref(const char *path) +{ + struct stat st; + char *buf, buffer[256]; + unsigned char sha1[20]; + int fd; + ssize_t len; + + if (lstat(path, &st) < 0) + return -1; + + /* Make sure it is a "refs/.." symlink */ + if (S_ISLNK(st.st_mode)) { + len = readlink(path, buffer, sizeof(buffer)-1); + if (len >= 5 && !memcmp("refs/", buffer, 5)) + return 0; + return -1; + } + + /* + * Anything else, just open it and try to see if it is a symbolic ref. + */ + fd = open(path, O_RDONLY); + if (fd < 0) + return -1; + len = read_in_full(fd, buffer, sizeof(buffer)-1); + close(fd); + + /* + * Is it a symbolic ref? + */ + if (len < 4) + return -1; + if (!memcmp("ref:", buffer, 4)) { + buf = buffer + 4; + len -= 4; + while (len && isspace(*buf)) + buf++, len--; + if (len >= 5 && !memcmp("refs/", buf, 5)) + return 0; + } + + /* + * Is this a detached HEAD? + */ + if (!get_sha1_hex(buffer, sha1)) + return 0; + + return -1; +} + +static struct passwd *getpw_str(const char *username, size_t len) +{ + struct passwd *pw; + char *username_z = xmalloc(len + 1); + memcpy(username_z, username, len); + username_z[len] = '\0'; + pw = getpwnam(username_z); + free(username_z); + return pw; +} + +/* + * Return a string with ~ and ~user expanded via getpw*. If buf != NULL, + * then it is a newly allocated string. Returns NULL on getpw failure or + * if path is NULL. + */ +char *expand_user_path(const char *path) +{ + struct strbuf user_path = STRBUF_INIT; + const char *first_slash = strchrnul(path, '/'); + const char *to_copy = path; + + if (path == NULL) + goto return_null; + if (path[0] == '~') { + const char *username = path + 1; + size_t username_len = first_slash - username; + if (username_len == 0) { + const char *home = getenv("HOME"); + if (!home) + goto return_null; + strbuf_add(&user_path, home, strlen(home)); + } else { + struct passwd *pw = getpw_str(username, username_len); + if (!pw) + goto return_null; + strbuf_add(&user_path, pw->pw_dir, strlen(pw->pw_dir)); + } + to_copy = first_slash; + } + strbuf_add(&user_path, to_copy, strlen(to_copy)); + return strbuf_detach(&user_path, NULL); +return_null: + strbuf_release(&user_path); + return NULL; +} + +/* + * First, one directory to try is determined by the following algorithm. + * + * (0) If "strict" is given, the path is used as given and no DWIM is + * done. Otherwise: + * (1) "~/path" to mean path under the running user's home directory; + * (2) "~user/path" to mean path under named user's home directory; + * (3) "relative/path" to mean cwd relative directory; or + * (4) "/absolute/path" to mean absolute directory. + * + * Unless "strict" is given, we try access() for existence of "%s.git/.git", + * "%s/.git", "%s.git", "%s" in this order. The first one that exists is + * what we try. + * + * Second, we try chdir() to that. Upon failure, we return NULL. + * + * Then, we try if the current directory is a valid git repository. + * Upon failure, we return NULL. + * + * If all goes well, we return the directory we used to chdir() (but + * before ~user is expanded), avoiding getcwd() resolving symbolic + * links. User relative paths are also returned as they are given, + * except DWIM suffixing. + */ +const char *enter_repo(const char *path, int strict) +{ + static char used_path[PATH_MAX]; + static char validated_path[PATH_MAX]; + + if (!path) + return NULL; + + if (!strict) { + static const char *suffix[] = { + ".git/.git", "/.git", ".git", "", NULL, + }; + const char *gitfile; + int len = strlen(path); + int i; + while ((1 < len) && (path[len-1] == '/')) + len--; + + if (PATH_MAX <= len) + return NULL; + strncpy(used_path, path, len); used_path[len] = 0 ; + strcpy(validated_path, used_path); + + if (used_path[0] == '~') { + char *newpath = expand_user_path(used_path); + if (!newpath || (PATH_MAX - 10 < strlen(newpath))) { + free(newpath); + return NULL; + } + /* + * Copy back into the static buffer. A pity + * since newpath was not bounded, but other + * branches of the if are limited by PATH_MAX + * anyway. + */ + strcpy(used_path, newpath); free(newpath); + } + else if (PATH_MAX - 10 < len) + return NULL; + len = strlen(used_path); + for (i = 0; suffix[i]; i++) { + strcpy(used_path + len, suffix[i]); + if (!access(used_path, F_OK)) { + strcat(validated_path, suffix[i]); + break; + } + } + if (!suffix[i]) + return NULL; + gitfile = read_gitfile(used_path) ; + if (gitfile) + strcpy(used_path, gitfile); + if (chdir(used_path)) + return NULL; + path = validated_path; + } + else if (chdir(path)) + return NULL; + + if (access("objects", X_OK) == 0 && access("refs", X_OK) == 0 && + validate_headref("HEAD") == 0) { + set_git_dir("."); + check_repository_format(); + return path; + } + + return NULL; +} + +int set_shared_perm(const char *path, int mode) +{ + struct stat st; + int tweak, shared, orig_mode; + + if (!shared_repository) { + if (mode) + return chmod(path, mode & ~S_IFMT); + return 0; + } + if (!mode) { + if (lstat(path, &st) < 0) + return -1; + mode = st.st_mode; + orig_mode = mode; + } else + orig_mode = 0; + if (shared_repository < 0) + shared = -shared_repository; + else + shared = shared_repository; + tweak = shared; + + if (!(mode & S_IWUSR)) + tweak &= ~0222; + if (mode & S_IXUSR) + /* Copy read bits to execute bits */ + tweak |= (tweak & 0444) >> 2; + if (shared_repository < 0) + mode = (mode & ~0777) | tweak; + else + mode |= tweak; + + if (S_ISDIR(mode)) { + /* Copy read bits to execute bits */ + mode |= (shared & 0444) >> 2; + mode |= FORCE_DIR_SET_GID; + } + + if (((shared_repository < 0 + ? (orig_mode & (FORCE_DIR_SET_GID | 0777)) + : (orig_mode & mode)) != mode) && + chmod(path, (mode & ~S_IFMT)) < 0) + return -2; + return 0; +} + +const char *relative_path(const char *abs, const char *base) +{ + static char buf[PATH_MAX + 1]; + int i = 0, j = 0; + + if (!base || !base[0]) + return abs; + while (base[i]) { + if (is_dir_sep(base[i])) { + if (!is_dir_sep(abs[j])) + return abs; + while (is_dir_sep(base[i])) + i++; + while (is_dir_sep(abs[j])) + j++; + continue; + } else if (abs[j] != base[i]) { + return abs; + } + i++; + j++; + } + if ( + /* "/foo" is a prefix of "/foo" */ + abs[j] && + /* "/foo" is not a prefix of "/foobar" */ + !is_dir_sep(base[i-1]) && !is_dir_sep(abs[j]) + ) + return abs; + while (is_dir_sep(abs[j])) + j++; + if (!abs[j]) + strcpy(buf, "."); + else + strcpy(buf, abs + j); + return buf; +} + +/* + * It is okay if dst == src, but they should not overlap otherwise. + * + * Performs the following normalizations on src, storing the result in dst: + * - Ensures that components are separated by '/' (Windows only) + * - Squashes sequences of '/'. + * - Removes "." components. + * - Removes ".." components, and the components the precede them. + * Returns failure (non-zero) if a ".." component appears as first path + * component anytime during the normalization. Otherwise, returns success (0). + * + * 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_path_copy(char *dst, const char *src) +{ + char *dst0; + + if (has_dos_drive_prefix(src)) { + *dst++ = *src++; + *dst++ = *src++; + } + dst0 = dst; + + if (is_dir_sep(*src)) { + *dst++ = '/'; + while (is_dir_sep(*src)) + src++; + } + + for (;;) { + char c = *src; + + /* + * A path component that begins with . could be + * special: + * (1) "." and ends -- ignore and terminate. + * (2) "./" -- ignore them, eat slash and continue. + * (3) ".." and ends -- strip one and terminate. + * (4) "../" -- strip one, eat slash and continue. + */ + if (c == '.') { + if (!src[1]) { + /* (1) */ + src++; + } else if (is_dir_sep(src[1])) { + /* (2) */ + src += 2; + while (is_dir_sep(*src)) + src++; + continue; + } else if (src[1] == '.') { + if (!src[2]) { + /* (3) */ + src += 2; + goto up_one; + } else if (is_dir_sep(src[2])) { + /* (4) */ + src += 3; + while (is_dir_sep(*src)) + src++; + goto up_one; + } + } + } + + /* copy up to the next '/', and eat all '/' */ + while ((c = *src++) != '\0' && !is_dir_sep(c)) + *dst++ = c; + if (is_dir_sep(c)) { + *dst++ = '/'; + while (is_dir_sep(c)) + c = *src++; + src--; + } else if (!c) + break; + continue; + + up_one: + /* + * dst0..dst is prefix portion, and dst[-1] is '/'; + * go up one level. + */ + dst--; /* go to trailing '/' */ + if (dst <= dst0) + return -1; + /* Windows: dst[-1] cannot be backslash anymore */ + while (dst0 < dst && dst[-1] != '/') + dst--; + } + *dst = '\0'; + return 0; +} + +/* + * path = Canonical absolute path + * prefix_list = Colon-separated list of absolute paths + * + * Determines, for each path in prefix_list, whether the "prefix" really + * is an ancestor directory of path. Returns the length of the longest + * ancestor directory, excluding any trailing slashes, or -1 if no prefix + * is an ancestor. (Note that this means 0 is returned if prefix_list is + * "/".) "/foo" is not considered an ancestor of "/foobar". Directories + * are not considered to be their own ancestors. path must be in a + * canonical form: empty components, or "." or ".." components are not + * allowed. prefix_list may be null, which is like "". + */ +int longest_ancestor_length(const char *path, const char *prefix_list) +{ + char buf[PATH_MAX+1]; + const char *ceil, *colon; + int len, max_len = -1; + + if (prefix_list == NULL || !strcmp(path, "/")) + return -1; + + for (colon = ceil = prefix_list; *colon; ceil = colon+1) { + for (colon = ceil; *colon && *colon != PATH_SEP; colon++); + len = colon - ceil; + if (len == 0 || len > PATH_MAX || !is_absolute_path(ceil)) + continue; + strlcpy(buf, ceil, len+1); + if (normalize_path_copy(buf, buf) < 0) + continue; + len = strlen(buf); + if (len > 0 && buf[len-1] == '/') + buf[--len] = '\0'; + + if (!strncmp(path, buf, len) && + path[len] == '/' && + len > max_len) { + max_len = len; + } + } + + return max_len; +} + +/* strip arbitrary amount of directory separators at end of path */ +static inline int chomp_trailing_dir_sep(const char *path, int len) +{ + while (len && is_dir_sep(path[len - 1])) + len--; + return len; +} + +/* + * If path ends with suffix (complete path components), returns the + * part before suffix (sans trailing directory separators). + * Otherwise returns NULL. + */ +char *strip_path_suffix(const char *path, const char *suffix) +{ + int path_len = strlen(path), suffix_len = strlen(suffix); + + while (suffix_len) { + if (!path_len) + return NULL; + + if (is_dir_sep(path[path_len - 1])) { + if (!is_dir_sep(suffix[suffix_len - 1])) + return NULL; + path_len = chomp_trailing_dir_sep(path, path_len); + suffix_len = chomp_trailing_dir_sep(suffix, suffix_len); + } + else if (path[--path_len] != suffix[--suffix_len]) + return NULL; + } + + if (path_len && !is_dir_sep(path[path_len - 1])) + return NULL; + return xstrndup(path, chomp_trailing_dir_sep(path, path_len)); +} + +int daemon_avoid_alias(const char *p) +{ + int sl, ndot; + + /* + * This resurrects the belts and suspenders paranoia check by HPA + * done in <435560F7.4080006@zytor.com> thread, now enter_repo() + * does not do getcwd() based path canonicalization. + * + * sl becomes true immediately after seeing '/' and continues to + * be true as long as dots continue after that without intervening + * non-dot character. + */ + if (!p || (*p != '/' && *p != '~')) + return -1; + sl = 1; ndot = 0; + p++; + + while (1) { + char ch = *p++; + if (sl) { + if (ch == '.') + ndot++; + else if (ch == '/') { + if (ndot < 3) + /* reject //, /./ and /../ */ + return -1; + ndot = 0; + } + else if (ch == 0) { + if (0 < ndot && ndot < 3) + /* reject /.$ and /..$ */ + return -1; + return 0; + } + else + sl = ndot = 0; + } + else if (ch == 0) + return 0; + else if (ch == '/') { + sl = 1; + ndot = 0; + } + } +} + +int offset_1st_component(const char *path) +{ + if (has_dos_drive_prefix(path)) + return 2 + is_dir_sep(path[2]); + return is_dir_sep(path[0]); +} |