Andrew's git - gitweb.git/blob

   1/*
   2 * I'm tired of doing "vsnprintf()" etc just to open a
   3 * file, so here's a "return static buffer with printf"
   4 * interface for paths.
   5 *
   6 * It's obviously not thread-safe. Sue me. But it's quite
   7 * useful for doing things like
   8 *
   9 *   f = open(mkpath("%s/%s.git", base, name), O_RDONLY);
  10 *
  11 * which is what it's designed for.
  12 */
  13#include "cache.h"
  14
  15static char bad_path[] = "/bad-path/";
  16
  17static char *get_pathname(void)
  18{
  19        static char pathname_array[4][PATH_MAX];
  20        static int index;
  21        return pathname_array[3 & ++index];
  22}
  23
  24static char *cleanup_path(char *path)
  25{
  26        /* Clean it up */
  27        if (!memcmp(path, "./", 2)) {
  28                path += 2;
  29                while (*path == '/')
  30                        path++;
  31        }
  32        return path;
  33}
  34
  35char *mkpath(const char *fmt, ...)
  36{
  37        va_list args;
  38        unsigned len;
  39        char *pathname = get_pathname();
  40
  41        va_start(args, fmt);
  42        len = vsnprintf(pathname, PATH_MAX, fmt, args);
  43        va_end(args);
  44        if (len >= PATH_MAX)
  45                return bad_path;
  46        return cleanup_path(pathname);
  47}
  48
  49char *git_path(const char *fmt, ...)
  50{
  51        const char *git_dir = get_git_dir();
  52        char *pathname = get_pathname();
  53        va_list args;
  54        unsigned len;
  55
  56        len = strlen(git_dir);
  57        if (len > PATH_MAX-100)
  58                return bad_path;
  59        memcpy(pathname, git_dir, len);
  60        if (len && git_dir[len-1] != '/')
  61                pathname[len++] = '/';
  62        va_start(args, fmt);
  63        len += vsnprintf(pathname + len, PATH_MAX - len, fmt, args);
  64        va_end(args);
  65        if (len >= PATH_MAX)
  66                return bad_path;
  67        return cleanup_path(pathname);
  68}
  69
  70
  71/* git_mkstemp() - create tmp file honoring TMPDIR variable */
  72int git_mkstemp(char *path, size_t len, const char *template)
  73{
  74        char *env, *pch = path;
  75
  76        if ((env = getenv("TMPDIR")) == NULL) {
  77                strcpy(pch, "/tmp/");
  78                len -= 5;
  79                pch += 5;
  80        } else {
  81                size_t n = snprintf(pch, len, "%s/", env);
  82
  83                len -= n;
  84                pch += n;
  85        }
  86
  87        strlcpy(pch, template, len);
  88
  89        return mkstemp(path);
  90}
  91
  92
  93int validate_headref(const char *path)
  94{
  95        struct stat st;
  96        char *buf, buffer[256];
  97        unsigned char sha1[20];
  98        int len, fd;
  99
 100        if (lstat(path, &st) < 0)
 101                return -1;
 102
 103        /* Make sure it is a "refs/.." symlink */
 104        if (S_ISLNK(st.st_mode)) {
 105                len = readlink(path, buffer, sizeof(buffer)-1);
 106                if (len >= 5 && !memcmp("refs/", buffer, 5))
 107                        return 0;
 108                return -1;
 109        }
 110
 111        /*
 112         * Anything else, just open it and try to see if it is a symbolic ref.
 113         */
 114        fd = open(path, O_RDONLY);
 115        if (fd < 0)
 116                return -1;
 117        len = read_in_full(fd, buffer, sizeof(buffer)-1);
 118        close(fd);
 119
 120        /*
 121         * Is it a symbolic ref?
 122         */
 123        if (len < 4)
 124                return -1;
 125        if (!memcmp("ref:", buffer, 4)) {
 126                buf = buffer + 4;
 127                len -= 4;
 128                while (len && isspace(*buf))
 129                        buf++, len--;
 130                if (len >= 5 && !memcmp("refs/", buf, 5))
 131                        return 0;
 132        }
 133
 134        /*
 135         * Is this a detached HEAD?
 136         */
 137        if (!get_sha1_hex(buffer, sha1))
 138                return 0;
 139
 140        return -1;
 141}
 142
 143static char *user_path(char *buf, char *path, int sz)
 144{
 145        struct passwd *pw;
 146        char *slash;
 147        int len, baselen;
 148
 149        if (!path || path[0] != '~')
 150                return NULL;
 151        path++;
 152        slash = strchr(path, '/');
 153        if (path[0] == '/' || !path[0]) {
 154                pw = getpwuid(getuid());
 155        }
 156        else {
 157                if (slash) {
 158                        *slash = 0;
 159                        pw = getpwnam(path);
 160                        *slash = '/';
 161                }
 162                else
 163                        pw = getpwnam(path);
 164        }
 165        if (!pw || !pw->pw_dir || sz <= strlen(pw->pw_dir))
 166                return NULL;
 167        baselen = strlen(pw->pw_dir);
 168        memcpy(buf, pw->pw_dir, baselen);
 169        while ((1 < baselen) && (buf[baselen-1] == '/')) {
 170                buf[baselen-1] = 0;
 171                baselen--;
 172        }
 173        if (slash && slash[1]) {
 174                len = strlen(slash);
 175                if (sz <= baselen + len)
 176                        return NULL;
 177                memcpy(buf + baselen, slash, len + 1);
 178        }
 179        return buf;
 180}
 181
 182/*
 183 * First, one directory to try is determined by the following algorithm.
 184 *
 185 * (0) If "strict" is given, the path is used as given and no DWIM is
 186 *     done. Otherwise:
 187 * (1) "~/path" to mean path under the running user's home directory;
 188 * (2) "~user/path" to mean path under named user's home directory;
 189 * (3) "relative/path" to mean cwd relative directory; or
 190 * (4) "/absolute/path" to mean absolute directory.
 191 *
 192 * Unless "strict" is given, we try access() for existence of "%s.git/.git",
 193 * "%s/.git", "%s.git", "%s" in this order.  The first one that exists is
 194 * what we try.
 195 *
 196 * Second, we try chdir() to that.  Upon failure, we return NULL.
 197 *
 198 * Then, we try if the current directory is a valid git repository.
 199 * Upon failure, we return NULL.
 200 *
 201 * If all goes well, we return the directory we used to chdir() (but
 202 * before ~user is expanded), avoiding getcwd() resolving symbolic
 203 * links.  User relative paths are also returned as they are given,
 204 * except DWIM suffixing.
 205 */
 206char *enter_repo(char *path, int strict)
 207{
 208        static char used_path[PATH_MAX];
 209        static char validated_path[PATH_MAX];
 210
 211        if (!path)
 212                return NULL;
 213
 214        if (!strict) {
 215                static const char *suffix[] = {
 216                        ".git/.git", "/.git", ".git", "", NULL,
 217                };
 218                int len = strlen(path);
 219                int i;
 220                while ((1 < len) && (path[len-1] == '/')) {
 221                        path[len-1] = 0;
 222                        len--;
 223                }
 224                if (PATH_MAX <= len)
 225                        return NULL;
 226                if (path[0] == '~') {
 227                        if (!user_path(used_path, path, PATH_MAX))
 228                                return NULL;
 229                        strcpy(validated_path, path);
 230                        path = used_path;
 231                }
 232                else if (PATH_MAX - 10 < len)
 233                        return NULL;
 234                else {
 235                        path = strcpy(used_path, path);
 236                        strcpy(validated_path, path);
 237                }
 238                len = strlen(path);
 239                for (i = 0; suffix[i]; i++) {
 240                        strcpy(path + len, suffix[i]);
 241                        if (!access(path, F_OK)) {
 242                                strcat(validated_path, suffix[i]);
 243                                break;
 244                        }
 245                }
 246                if (!suffix[i] || chdir(path))
 247                        return NULL;
 248                path = validated_path;
 249        }
 250        else if (chdir(path))
 251                return NULL;
 252
 253        if (access("objects", X_OK) == 0 && access("refs", X_OK) == 0 &&
 254            validate_headref("HEAD") == 0) {
 255                setenv(GIT_DIR_ENVIRONMENT, ".", 1);
 256                check_repository_format();
 257                return path;
 258        }
 259
 260        return NULL;
 261}
 262
 263int adjust_shared_perm(const char *path)
 264{
 265        struct stat st;
 266        int mode;
 267
 268        if (!shared_repository)
 269                return 0;
 270        if (lstat(path, &st) < 0)
 271                return -1;
 272        mode = st.st_mode;
 273        if (mode & S_IRUSR)
 274                mode |= (shared_repository == PERM_GROUP
 275                         ? S_IRGRP
 276                         : (shared_repository == PERM_EVERYBODY
 277                            ? (S_IRGRP|S_IROTH)
 278                            : 0));
 279
 280        if (mode & S_IWUSR)
 281                mode |= S_IWGRP;
 282
 283        if (mode & S_IXUSR)
 284                mode |= (shared_repository == PERM_GROUP
 285                         ? S_IXGRP
 286                         : (shared_repository == PERM_EVERYBODY
 287                            ? (S_IXGRP|S_IXOTH)
 288                            : 0));
 289        if (S_ISDIR(mode))
 290                mode |= S_ISGID;
 291        if ((mode & st.st_mode) != mode && chmod(path, mode) < 0)
 292                return -2;
 293        return 0;
 294}