Merge branch 'sb/rerere-lib'
[gitweb.git] / path.c
diff --git a/path.c b/path.c
index af2716199b92e920df9fe2021035d319e8cafbc6..504eae061fe27e846f67f3e1c25d51e886420b62 100644 (file)
--- a/path.c
+++ b/path.c
@@ -91,7 +91,8 @@ int validate_headref(const char *path)
        struct stat st;
        char *buf, buffer[256];
        unsigned char sha1[20];
-       int len, fd;
+       int fd;
+       ssize_t len;
 
        if (lstat(path, &st) < 0)
                return -1;
@@ -266,92 +267,175 @@ int adjust_shared_perm(const char *path)
        if (lstat(path, &st) < 0)
                return -1;
        mode = st.st_mode;
-       if (mode & S_IRUSR)
-               mode |= (shared_repository == PERM_GROUP
-                        ? S_IRGRP
-                        : (shared_repository == PERM_EVERYBODY
-                           ? (S_IRGRP|S_IROTH)
-                           : 0));
-
-       if (mode & S_IWUSR)
-               mode |= S_IWGRP;
-
-       if (mode & S_IXUSR)
-               mode |= (shared_repository == PERM_GROUP
-                        ? S_IXGRP
-                        : (shared_repository == PERM_EVERYBODY
-                           ? (S_IXGRP|S_IXOTH)
-                           : 0));
-       if (S_ISDIR(mode))
-               mode |= S_ISGID;
+
+       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;
 }
 
-/* We allow "recursive" symbolic links. Only within reason, though. */
-#define MAXDEPTH 5
+static const char *get_pwd_cwd(void)
+{
+       static char cwd[PATH_MAX + 1];
+       char *pwd;
+       struct stat cwd_stat, pwd_stat;
+       if (getcwd(cwd, PATH_MAX) == NULL)
+               return NULL;
+       pwd = getenv("PWD");
+       if (pwd && strcmp(pwd, cwd)) {
+               stat(cwd, &cwd_stat);
+               if (!stat(pwd, &pwd_stat) &&
+                   pwd_stat.st_dev == cwd_stat.st_dev &&
+                   pwd_stat.st_ino == cwd_stat.st_ino) {
+                       strlcpy(cwd, pwd, PATH_MAX);
+               }
+       }
+       return cwd;
+}
 
-const char *make_absolute_path(const char *path)
+const char *make_nonrelative_path(const char *path)
 {
-       static char bufs[2][PATH_MAX + 1], *buf = bufs[0], *next_buf = bufs[1];
-       char cwd[1024] = "";
-       int buf_index = 1, len;
+       static char buf[PATH_MAX + 1];
+
+       if (is_absolute_path(path)) {
+               if (strlcpy(buf, path, PATH_MAX) >= PATH_MAX)
+                       die ("Too long path: %.*s", 60, path);
+       } else {
+               const char *cwd = get_pwd_cwd();
+               if (!cwd)
+                       die("Cannot determine the current working directory");
+               if (snprintf(buf, PATH_MAX, "%s/%s", cwd, path) >= PATH_MAX)
+                       die ("Too long path: %.*s", 60, path);
+       }
+       return buf;
+}
 
-       int depth = MAXDEPTH;
-       char *last_elem = NULL;
-       struct stat st;
+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;
+}
 
-       if (strlcpy(buf, path, PATH_MAX) >= PATH_MAX)
-               die ("Too long path: %.*s", 60, path);
-
-       while (depth--) {
-               if (stat(buf, &st) || !S_ISDIR(st.st_mode)) {
-                       char *last_slash = strrchr(buf, '/');
-                       if (last_slash) {
-                               *last_slash = '\0';
-                               last_elem = xstrdup(last_slash + 1);
-                       } else {
-                               last_elem = xstrdup(buf);
-                               *buf = '\0';
-                       }
+/*
+ * 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;
                }
 
-               if (*buf) {
-                       if (!*cwd && !getcwd(cwd, sizeof(cwd)))
-                               die ("Could not get current working directory");
+               memcpy(dst, comp_start, comp_len);
+               dst += comp_len;
+       next:
+               comp_start = comp_end;
+       }
 
-                       if (chdir(buf))
-                               die ("Could not switch to '%s'", buf);
-               }
-               if (!getcwd(buf, PATH_MAX))
-                       die ("Could not get current working directory");
-
-               if (last_elem) {
-                       int len = strlen(buf);
-                       if (len + strlen(last_elem) + 2 > PATH_MAX)
-                               die ("Too long path name: '%s/%s'",
-                                               buf, last_elem);
-                       buf[len] = '/';
-                       strcpy(buf + len + 1, last_elem);
-                       free(last_elem);
-                       last_elem = NULL;
-               }
+       if (dst == buf)
+               *dst++ = '/';
 
-               if (!lstat(buf, &st) && S_ISLNK(st.st_mode)) {
-                       len = readlink(buf, next_buf, PATH_MAX);
-                       if (len < 0)
-                               die ("Invalid symlink: %s", buf);
-                       next_buf[len] = '\0';
-                       buf = next_buf;
-                       buf_index = 1 - buf_index;
-                       next_buf = bufs[buf_index];
-               } else
-                       break;
-       }
+       *dst = '\0';
+       return dst - buf;
+}
 
-       if (*cwd && chdir(cwd))
-               die ("Could not change back to '%s'", cwd);
+/*
+ * path = Canonical absolute path
+ * prefix_list = Colon-separated list of absolute paths
+ *
+ * Determines, for each path in parent_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;
 
-       return buf;
+       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;
 }