git-fetch: document automatic tag following.
[gitweb.git] / path.c
diff --git a/path.c b/path.c
index 2c077c0c8f7066c5338050ce890c0846adedf6bd..c5d25a4b903bd92930df4004d30d4dffa6054456 100644 (file)
--- a/path.c
+++ b/path.c
  * which is what it's designed for.
  */
 #include "cache.h"
-#include <pwd.h>
 
-static char pathname[PATH_MAX];
 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 */
@@ -31,6 +36,7 @@ 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);
@@ -43,6 +49,7 @@ char *mkpath(const char *fmt, ...)
 char *git_path(const char *fmt, ...)
 {
        const char *git_dir = get_git_dir();
+       char *pathname = get_pathname();
        va_list args;
        unsigned len;
 
@@ -77,24 +84,17 @@ int git_mkstemp(char *path, size_t len, const char *template)
                pch += n;
        }
 
-       safe_strncpy(pch, template, len);
+       strlcpy(pch, template, len);
 
        return mkstemp(path);
 }
 
 
-char *safe_strncpy(char *dest, const char *src, size_t n)
-{
-       strncpy(dest, src, n);
-       dest[n - 1] = '\0';
-
-       return dest;
-}
-
-int validate_symref(const char *path)
+int validate_headref(const char *path)
 {
        struct stat st;
        char *buf, buffer[256];
+       unsigned char sha1[20];
        int len, fd;
 
        if (lstat(path, &st) < 0)
@@ -114,94 +114,181 @@ int validate_symref(const char *path)
        fd = open(path, O_RDONLY);
        if (fd < 0)
                return -1;
-       len = read(fd, buffer, sizeof(buffer)-1);
+       len = read_in_full(fd, buffer, sizeof(buffer)-1);
        close(fd);
 
        /*
         * Is it a symbolic ref?
         */
-       if (len < 4 || memcmp("ref:", buffer, 4))
+       if (len < 4)
                return -1;
-       buf = buffer + 4;
-       len -= 4;
-       while (len && isspace(*buf))
-               buf++, len--;
-       if (len >= 5 && !memcmp("refs/", buf, 5))
+       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 *current_dir(void)
-{
-       return getcwd(pathname, sizeof(pathname));
+       return -1;
 }
 
-static int user_chdir(char *path)
+static char *user_path(char *buf, char *path, int sz)
 {
-       char *dir = path;
+       struct passwd *pw;
+       char *slash;
+       int len, baselen;
 
-       if(*dir == '~') {               /* user-relative path */
-               struct passwd *pw;
-               char *slash = strchr(dir, '/');
-
-               dir++;
-               /* '~/' and '~' (no slash) means users own home-dir */
-               if(!*dir || *dir == '/')
-                       pw = getpwuid(getuid());
-               else {
-                       if (slash) {
-                               *slash = '\0';
-                               pw = getpwnam(dir);
-                               *slash = '/';
-                       }
-                       else
-                               pw = getpwnam(dir);
+       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 = '/';
                }
-
-               /* make sure we got something back that we can chdir() to */
-               if(!pw || chdir(pw->pw_dir) < 0)
-                       return -1;
-
-               if(!slash || !slash[1]) /* no path following username */
-                       return 0;
-
-               dir = slash + 1;
+               else
+                       pw = getpwnam(path);
        }
-
-       /* ~foo/path/to/repo is now path/to/repo and we're in foo's homedir */
-       if(chdir(dir) < 0)
-               return -1;
-
-       return 0;
+       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)
 {
-       if(!path)
+       static char used_path[PATH_MAX];
+       static char validated_path[PATH_MAX];
+
+       if (!path)
                return NULL;
 
-       if (strict) {
-               if (chdir(path) < 0)
+       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;
-       }
-       else {
-               if (!*path)
-                       ; /* happy -- no chdir */
-               else if (!user_chdir(path))
-                       ; /* happy -- as given */
-               else if (!user_chdir(mkpath("%s.git", path)))
-                       ; /* happy -- uemacs --> uemacs.git */
-               else
+               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;
-               (void)chdir(".git");
+               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_symref("HEAD") == 0) {
+       if (access("objects", X_OK) == 0 && access("refs", X_OK) == 0 &&
+           validate_headref("HEAD") == 0) {
                putenv("GIT_DIR=.");
                check_repository_format();
-               return current_dir();
+               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 (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 ((mode & st.st_mode) != mode && chmod(path, mode) < 0)
+               return -2;
+       return 0;
+}