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git/path.c
Michael Haggerty 9e2326c7e1 longest_ancestor_length(): require prefix list entries to be normalized
Move the responsibility for normalizing prefixes from
longest_ancestor_length() to its callers. Use slightly different
normalizations at the two callers:

In setup_git_directory_gently_1(), use the old normalization, which
ignores paths that are not usable.  In the next commit we will change
this caller to also resolve symlinks in the paths from
GIT_CEILING_DIRECTORIES as part of the normalization.

In "test-path-utils longest_ancestor_length", use the old
normalization, but die() if any paths are unusable.  Also change t0060
to only pass normalized paths to the test program (no empty entries or
non-absolute paths, strip trailing slashes from the paths, and remove
tests that thereby become redundant).

The point of this change is to reduce the scope of the ancestor_length
tests in t0060 from testing normalization+longest_prefix to testing
only mostly longest_prefix.  This is necessary because when
setup_git_directory_gently_1() starts resolving symlinks as part of
its normalization, it will not be reasonable to do the same in the
test suite, because that would make the test results depend on the
contents of the root directory of the filesystem on which the test is
run.  HOWEVER: under Windows, bash mangles arguments that look like
absolute POSIX paths into DOS paths.  So we have to retain the level
of normalization done by normalize_path_copy() to convert the
bash-mangled DOS paths (which contain backslashes) into paths that use
forward slashes.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Jeff King <peff@peff.net>
2012-10-29 02:34:58 -04:00

698 lines
15 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"
#include "string-list.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 *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, ...)
{
char *ret;
va_list args;
va_start(args, fmt);
ret = vsnpath(buf, n, fmt, args);
va_end(args);
return ret;
}
char *git_pathdup(const char *fmt, ...)
{
char path[PATH_MAX], *ret;
va_list args;
va_start(args, fmt);
ret = vsnpath(path, sizeof(path), fmt, args);
va_end(args);
return xstrdup(ret);
}
char *mkpathdup(const char *fmt, ...)
{
char *path;
struct strbuf sb = STRBUF_INIT;
va_list args;
va_start(args, fmt);
strbuf_vaddf(&sb, fmt, args);
va_end(args);
path = xstrdup(cleanup_path(sb.buf));
strbuf_release(&sb);
return 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, ...)
{
char *pathname = get_pathname();
va_list args;
char *ret;
va_start(args, fmt);
ret = vsnpath(pathname, PATH_MAX, fmt, args);
va_end(args);
return ret;
}
void home_config_paths(char **global, char **xdg, char *file)
{
char *xdg_home = getenv("XDG_CONFIG_HOME");
char *home = getenv("HOME");
char *to_free = NULL;
if (!home) {
if (global)
*global = NULL;
} else {
if (!xdg_home) {
to_free = mkpathdup("%s/.config", home);
xdg_home = to_free;
}
if (global)
*global = mkpathdup("%s/.gitconfig", home);
}
if (!xdg_home)
*xdg = NULL;
else
*xdg = mkpathdup("%s/git/%s", xdg_home, file);
free(to_free);
}
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++) {
struct stat st;
strcpy(used_path + len, suffix[i]);
if (!stat(used_path, &st) &&
(S_ISREG(st.st_mode) ||
(S_ISDIR(st.st_mode) && is_git_directory(used_path)))) {
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
* prefixes = string_list containing normalized, absolute paths without
* trailing slashes (except for the root directory, which is denoted by "/").
*
* Determines, for each path in prefixes, whether the "prefix"
* 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 prefixes 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.
*/
int longest_ancestor_length(const char *path, struct string_list *prefixes)
{
int i, max_len = -1;
if (!strcmp(path, "/"))
return -1;
for (i = 0; i < prefixes->nr; i++) {
const char *ceil = prefixes->items[i].string;
int len = strlen(ceil);
if (len == 1 && ceil[0] == '/')
len = 0; /* root matches anything, with length 0 */
else if (!strncmp(path, ceil, len) && path[len] == '/')
; /* match of length len */
else
continue; /* no match */
if (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]);
}