git-format-patch --start-number <n>
[gitweb.git] / refs.c
diff --git a/refs.c b/refs.c
index 7ccd721a4abdfec68fa9cab1f380569152fe61e9..0f3491f871bd692151b42307b833e633b041e948 100644 (file)
--- a/refs.c
+++ b/refs.c
 
 #include <errno.h>
 
-static int read_ref(const char *path, unsigned char *sha1)
+/* We allow "recursive" symbolic refs. Only within reason, though */
+#define MAXDEPTH 5
+
+const char *resolve_ref(const char *path, unsigned char *sha1, int reading)
 {
-       int ret = -1;
-       int fd = open(path, O_RDONLY);
+       int depth = MAXDEPTH, len;
+       char buffer[256];
+
+       for (;;) {
+               struct stat st;
+               char *buf;
+               int fd;
+
+               if (--depth < 0)
+                       return NULL;
+
+               /* Special case: non-existing file.
+                * Not having the refs/heads/new-branch is OK
+                * if we are writing into it, so is .git/HEAD
+                * that points at refs/heads/master still to be
+                * born.  It is NOT OK if we are resolving for
+                * reading.
+                */
+               if (lstat(path, &st) < 0) {
+                       if (reading || errno != ENOENT)
+                               return NULL;
+                       memset(sha1, 0, 20);
+                       return path;
+               }
+
+               /* Follow "normalized" - ie "refs/.." symlinks by hand */
+               if (S_ISLNK(st.st_mode)) {
+                       len = readlink(path, buffer, sizeof(buffer)-1);
+                       if (len >= 5 && !memcmp("refs/", buffer, 5)) {
+                               path = git_path("%.*s", len, buffer);
+                               continue;
+                       }
+               }
 
-       if (fd >= 0) {
-               char buffer[60];
-               if (read(fd, buffer, sizeof(buffer)) >= 40)
-                       ret = get_sha1_hex(buffer, sha1);
+               /*
+                * Anything else, just open it and try to use it as
+                * a ref
+                */
+               fd = open(path, O_RDONLY);
+               if (fd < 0)
+                       return NULL;
+               len = read(fd, buffer, sizeof(buffer)-1);
                close(fd);
+
+               /*
+                * Is it a symbolic ref?
+                */
+               if (len < 4 || memcmp("ref:", buffer, 4))
+                       break;
+               buf = buffer + 4;
+               len -= 4;
+               while (len && isspace(*buf))
+                       buf++, len--;
+               while (len && isspace(buf[len-1]))
+                       buf[--len] = 0;
+               path = git_path("%.*s", len, buf);
        }
-       return ret;
+       if (len < 40 || get_sha1_hex(buffer, sha1))
+               return NULL;
+       return path;
 }
 
-static int do_for_each_ref(const char *base, int (*fn)(const char *path, const unsigned char *sha1))
+int create_symref(const char *git_HEAD, const char *refs_heads_master)
+{
+       const char *lockpath;
+       char ref[1000];
+       int fd, len, written;
+
+#ifndef NO_SYMLINK_HEAD
+       if (prefer_symlink_refs) {
+               unlink(git_HEAD);
+               if (!symlink(refs_heads_master, git_HEAD))
+                       return 0;
+               fprintf(stderr, "no symlink - falling back to symbolic ref\n");
+       }
+#endif
+
+       len = snprintf(ref, sizeof(ref), "ref: %s\n", refs_heads_master);
+       if (sizeof(ref) <= len) {
+               error("refname too long: %s", refs_heads_master);
+               return -1;
+       }
+       lockpath = mkpath("%s.lock", git_HEAD);
+       fd = open(lockpath, O_CREAT | O_EXCL | O_WRONLY, 0666); 
+       written = write(fd, ref, len);
+       close(fd);
+       if (written != len) {
+               unlink(lockpath);
+               error("Unable to write to %s", lockpath);
+               return -2;
+       }
+       if (rename(lockpath, git_HEAD) < 0) {
+               unlink(lockpath);
+               error("Unable to create %s", git_HEAD);
+               return -3;
+       }
+       return 0;
+}
+
+int read_ref(const char *filename, unsigned char *sha1)
+{
+       if (resolve_ref(filename, sha1, 1))
+               return 0;
+       return -1;
+}
+
+static int do_for_each_ref(const char *base, int (*fn)(const char *path, const unsigned char *sha1), int trim)
 {
        int retval = 0;
-       DIR *dir = opendir(base);
+       DIR *dir = opendir(git_path("%s", base));
 
        if (dir) {
                struct dirent *de;
@@ -46,19 +143,24 @@ static int do_for_each_ref(const char *base, int (*fn)(const char *path, const u
                        if (namelen > 255)
                                continue;
                        memcpy(path + baselen, de->d_name, namelen+1);
-                       if (lstat(path, &st) < 0)
+                       if (stat(git_path("%s", path), &st) < 0)
                                continue;
                        if (S_ISDIR(st.st_mode)) {
-                               retval = do_for_each_ref(path, fn);
+                               retval = do_for_each_ref(path, fn, trim);
                                if (retval)
                                        break;
                                continue;
                        }
-                       if (read_ref(path, sha1) < 0)
+                       if (read_ref(git_path("%s", path), sha1) < 0) {
+                               error("%s points nowhere!", path);
                                continue;
-                       if (!has_sha1_file(sha1))
+                       }
+                       if (!has_sha1_file(sha1)) {
+                               error("%s does not point to a valid "
+                                     "commit object!", path);
                                continue;
-                       retval = fn(path, sha1);
+                       }
+                       retval = fn(path + trim, sha1);
                        if (retval)
                                break;
                }
@@ -68,9 +170,32 @@ static int do_for_each_ref(const char *base, int (*fn)(const char *path, const u
        return retval;
 }
 
+int head_ref(int (*fn)(const char *path, const unsigned char *sha1))
+{
+       unsigned char sha1[20];
+       if (!read_ref(git_path("HEAD"), sha1))
+               return fn("HEAD", sha1);
+       return 0;
+}
+
 int for_each_ref(int (*fn)(const char *path, const unsigned char *sha1))
 {
-       return do_for_each_ref(get_refs_directory(), fn);
+       return do_for_each_ref("refs", fn, 0);
+}
+
+int for_each_tag_ref(int (*fn)(const char *path, const unsigned char *sha1))
+{
+       return do_for_each_ref("refs/tags", fn, 10);
+}
+
+int for_each_branch_ref(int (*fn)(const char *path, const unsigned char *sha1))
+{
+       return do_for_each_ref("refs/heads", fn, 11);
+}
+
+int for_each_remote_ref(int (*fn)(const char *path, const unsigned char *sha1))
+{
+       return do_for_each_ref("refs/remotes", fn, 13);
 }
 
 static char *ref_file_name(const char *ref)
@@ -93,33 +218,11 @@ static char *ref_lock_file_name(const char *ref)
        return ret;
 }
 
-static int read_ref_file(const char *filename, unsigned char *sha1) {
-       int fd = open(filename, O_RDONLY);
-       char hex[41];
-       if (fd < 0) {
-               return error("Couldn't open %s\n", filename);
-       }
-       if ((read(fd, hex, 41) < 41) ||
-           (hex[40] != '\n') ||
-           get_sha1_hex(hex, sha1)) {
-               error("Couldn't read a hash from %s\n", filename);
-               close(fd);
-               return -1;
-       }
-       close(fd);
-       return 0;
-}
-
 int get_ref_sha1(const char *ref, unsigned char *sha1)
 {
-       char *filename;
-       int retval;
        if (check_ref_format(ref))
                return -1;
-       filename = ref_file_name(ref);
-       retval = read_ref_file(filename, sha1);
-       free(filename);
-       return retval;
+       return read_ref(git_path("refs/%s", ref), sha1);
 }
 
 static int lock_ref_file(const char *filename, const char *lock_filename,
@@ -132,7 +235,7 @@ static int lock_ref_file(const char *filename, const char *lock_filename,
                return error("Couldn't open lock file for %s: %s",
                             filename, strerror(errno));
        }
-       retval = read_ref_file(filename, current_sha1);
+       retval = read_ref(filename, current_sha1);
        if (old_sha1) {
                if (retval) {
                        close(fd);
@@ -182,7 +285,7 @@ static int write_ref_file(const char *filename,
        char term = '\n';
        if (write(fd, hex, 40) < 40 ||
            write(fd, &term, 1) < 1) {
-               error("Couldn't write %s\n", filename);
+               error("Couldn't write %s", filename);
                close(fd);
                return -1;
        }
@@ -202,23 +305,64 @@ int write_ref_sha1(const char *ref, int fd, const unsigned char *sha1)
                return -1;
        filename = ref_file_name(ref);
        lock_filename = ref_lock_file_name(ref);
+       if (safe_create_leading_directories(filename))
+               die("unable to create leading directory for %s", filename);
        retval = write_ref_file(filename, lock_filename, fd, sha1);
        free(filename);
        free(lock_filename);
        return retval;
 }
 
+/*
+ * Make sure "ref" is something reasonable to have under ".git/refs/";
+ * We do not like it if:
+ *
+ * - any path component of it begins with ".", or
+ * - it has double dots "..", or
+ * - it has ASCII control character, "~", "^", ":" or SP, anywhere, or
+ * - it ends with a "/".
+ */
+
+static inline int bad_ref_char(int ch)
+{
+       return (((unsigned) ch) <= ' ' ||
+               ch == '~' || ch == '^' || ch == ':' ||
+               /* 2.13 Pattern Matching Notation */
+               ch == '?' || ch == '*' || ch == '[');
+}
+
 int check_ref_format(const char *ref)
 {
-       char *middle;
-       if (ref[0] == '.' || ref[0] == '/')
-               return -1;
-       middle = strchr(ref, '/');
-       if (!middle || !middle[1])
-               return -1;
-       if (strchr(middle + 1, '/'))
-               return -1;
-       return 0;
+       int ch, level;
+       const char *cp = ref;
+
+       level = 0;
+       while (1) {
+               while ((ch = *cp++) == '/')
+                       ; /* tolerate duplicated slashes */
+               if (!ch)
+                       return -1; /* should not end with slashes */
+
+               /* we are at the beginning of the path component */
+               if (ch == '.' || bad_ref_char(ch))
+                       return -1;
+
+               /* scan the rest of the path component */
+               while ((ch = *cp++) != 0) {
+                       if (bad_ref_char(ch))
+                               return -1;
+                       if (ch == '/')
+                               break;
+                       if (ch == '.' && *cp == '.')
+                               return -1;
+               }
+               level++;
+               if (!ch) {
+                       if (level < 2)
+                               return -1; /* at least of form "heads/blah" */
+                       return 0;
+               }
+       }
 }
 
 int write_ref_sha1_unlocked(const char *ref, const unsigned char *sha1)
@@ -231,6 +375,8 @@ int write_ref_sha1_unlocked(const char *ref, const unsigned char *sha1)
                return -1;
        filename = ref_file_name(ref);
        lock_filename = ref_lock_file_name(ref);
+       if (safe_create_leading_directories(filename))
+               die("unable to create leading directory for %s", filename);
        fd = open(lock_filename, O_WRONLY | O_CREAT | O_EXCL, 0666);
        if (fd < 0) {
                error("Writing %s", lock_filename);