git/path.c
Junio C Hamano 288123f01c ignore duplicated slashes in make_relative_path()
The function takes two paths, an early part of abs is supposed to match
base; otherwise abs is not a path under base and the function returns the
full path of abs.  The caller can easily confuse the implementation by
giving duplicated and needless slashes in these path arguments.

Credit for test script, motivation and initial patch goes to Thomas Rast.
A follow-up fix (squashed) is by Hannes.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
2010-01-22 15:34:56 -08:00

652 lines
14 KiB
C

/*
* 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);
}
/* git_mkstemp() - create tmp file honoring TMPDIR variable */
int git_mkstemp(char *path, size_t len, const char *template)
{
const char *tmp;
size_t n;
tmp = getenv("TMPDIR");
if (!tmp)
tmp = "/tmp";
n = snprintf(path, len, "%s/%s", tmp, template);
if (len <= n) {
errno = ENAMETOOLONG;
return -1;
}
return mkstemp(path);
}
/* git_mkstemps() - create tmp file with suffix honoring TMPDIR variable. */
int git_mkstemps(char *path, size_t len, const char *template, int suffix_len)
{
const char *tmp;
size_t n;
tmp = getenv("TMPDIR");
if (!tmp)
tmp = "/tmp";
n = snprintf(path, len, "%s/%s", tmp, template);
if (len <= n) {
errno = ENAMETOOLONG;
return -1;
}
return mkstemps(path, suffix_len);
}
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");
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.
*/
char *enter_repo(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,
};
int len = strlen(path);
int i;
while ((1 < len) && (path[len-1] == '/')) {
path[len-1] = 0;
len--;
}
if (PATH_MAX <= len)
return NULL;
if (path[0] == '~') {
char *newpath = expand_user_path(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);
strcpy(validated_path, path);
path = used_path;
}
else if (PATH_MAX - 10 < len)
return NULL;
else {
path = strcpy(used_path, path);
strcpy(validated_path, path);
}
len = strlen(path);
for (i = 0; suffix[i]; i++) {
strcpy(path + len, suffix[i]);
if (!access(path, F_OK)) {
strcat(validated_path, suffix[i]);
break;
}
}
if (!suffix[i] || chdir(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) {
setenv(GIT_DIR_ENVIRONMENT, ".", 1);
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 *make_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 canonicalizations.
*
* 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;
}
}
}