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/*
* 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"
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 *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);
}
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 char *user_path(char *buf, char *path, int sz)
{
struct passwd *pw;
char *slash;
int len, baselen;
if (!path || path[0] != '~')
return NULL;
path++;
slash = strchr(path, '/');
if (path[0] == '/' || !path[0]) {
pw = getpwuid(getuid());
}
else {
if (slash) {
*slash = 0;
pw = getpwnam(path);
*slash = '/';
}
else
pw = getpwnam(path);
}
if (!pw || !pw->pw_dir || sz <= strlen(pw->pw_dir))
return NULL;
baselen = strlen(pw->pw_dir);
memcpy(buf, pw->pw_dir, baselen);
while ((1 < baselen) && (buf[baselen-1] == '/')) {
buf[baselen-1] = 0;
baselen--;
}
if (slash && slash[1]) {
len = strlen(slash);
if (sz <= baselen + len)
return NULL;
memcpy(buf + baselen, slash, len + 1);
}
return buf;
}
/*
* 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] == '~') {
if (!user_path(used_path, path, PATH_MAX))
return NULL;
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 adjust_shared_perm(const char *path)
{
struct stat st;
int mode;
if (!shared_repository)
return 0;
if (lstat(path, &st) < 0)
return -1;
mode = st.st_mode;
if (shared_repository) {
int tweak = shared_repository;
if (!(mode & S_IWUSR))
tweak &= ~0222;
mode |= tweak;
} else {
/* Preserve old PERM_UMASK behaviour */
if (mode & S_IWUSR)
mode |= S_IWGRP;
}
if (S_ISDIR(mode)) {
mode |= FORCE_DIR_SET_GID;
/* Copy read bits to execute bits */
mode |= (shared_repository & 0444) >> 2;
}
if ((mode & st.st_mode) != mode && chmod(path, mode) < 0)
return -2;
return 0;
}
const char *make_relative_path(const char *abs, const char *base)
{
static char buf[PATH_MAX + 1];
int baselen;
if (!base)
return abs;
baselen = strlen(base);
if (prefixcmp(abs, base))
return abs;
if (abs[baselen] == '/')
baselen++;
else if (base[baselen - 1] != '/')
return abs;
strcpy(buf, abs + baselen);
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;
}
/*
* 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 != ':'; colon++);
len = colon - ceil;
if (len == 0 || len > PATH_MAX || !is_absolute_path(ceil))
continue;
strlcpy(buf, ceil, len+1);
len = normalize_absolute_path(buf, buf);
/* Strip "trailing slashes" from "/". */
if (len == 1)
len = 0;
if (!strncmp(path, buf, len) &&
path[len] == '/' &&
len > max_len) {
max_len = len;
}
}
return max_len;
}
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