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#include <pwd.h>
  15
  16static char bad_path[] = "/bad-path/";
  17
  18static char *get_pathname(void)
  19{
  20        static char pathname_array[4][PATH_MAX];
  21        static int index;
  22        return pathname_array[3 & ++index];
  23}
  24
  25static char *cleanup_path(char *path)
  26{
  27        /* Clean it up */
  28        if (!memcmp(path, "./", 2)) {
  29                path += 2;
  30                while (*path == '/')
  31                        path++;
  32        }
  33        return path;
  34}
  35
  36char *mkpath(const char *fmt, ...)
  37{
  38        va_list args;
  39        unsigned len;
  40        char *pathname = get_pathname();
  41
  42        va_start(args, fmt);
  43        len = vsnprintf(pathname, PATH_MAX, fmt, args);
  44        va_end(args);
  45        if (len >= PATH_MAX)
  46                return bad_path;
  47        return cleanup_path(pathname);
  48}
  49
  50char *git_path(const char *fmt, ...)
  51{
  52        const char *git_dir = get_git_dir();
  53        char *pathname = get_pathname();
  54        va_list args;
  55        unsigned len;
  56
  57        len = strlen(git_dir);
  58        if (len > PATH_MAX-100)
  59                return bad_path;
  60        memcpy(pathname, git_dir, len);
  61        if (len && git_dir[len-1] != '/')
  62                pathname[len++] = '/';
  63        va_start(args, fmt);
  64        len += vsnprintf(pathname + len, PATH_MAX - len, fmt, args);
  65        va_end(args);
  66        if (len >= PATH_MAX)
  67                return bad_path;
  68        return cleanup_path(pathname);
  69}
  70
  71
  72/* git_mkstemp() - create tmp file honoring TMPDIR variable */
  73int git_mkstemp(char *path, size_t len, const char *template)
  74{
  75        char *env, *pch = path;
  76
  77        if ((env = getenv("TMPDIR")) == NULL) {
  78                strcpy(pch, "/tmp/");
  79                len -= 5;
  80                pch += 5;
  81        } else {
  82                size_t n = snprintf(pch, len, "%s/", env);
  83
  84                len -= n;
  85                pch += n;
  86        }
  87
  88        strlcpy(pch, template, len);
  89
  90        return mkstemp(path);
  91}
  92
  93
  94int validate_symref(const char *path)
  95{
  96        struct stat st;
  97        char *buf, buffer[256];
  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(fd, buffer, sizeof(buffer)-1);
 118        close(fd);
 119
 120        /*
 121         * Is it a symbolic ref?
 122         */
 123        if (len < 4 || memcmp("ref:", buffer, 4))
 124                return -1;
 125        buf = buffer + 4;
 126        len -= 4;
 127        while (len && isspace(*buf))
 128                buf++, len--;
 129        if (len >= 5 && !memcmp("refs/", buf, 5))
 130                return 0;
 131        return -1;
 132}
 133
 134static char *user_path(char *buf, char *path, int sz)
 135{
 136        struct passwd *pw;
 137        char *slash;
 138        int len, baselen;
 139
 140        if (!path || path[0] != '~')
 141                return NULL;
 142        path++;
 143        slash = strchr(path, '/');
 144        if (path[0] == '/' || !path[0]) {
 145                pw = getpwuid(getuid());
 146        }
 147        else {
 148                if (slash) {
 149                        *slash = 0;
 150                        pw = getpwnam(path);
 151                        *slash = '/';
 152                }
 153                else
 154                        pw = getpwnam(path);
 155        }
 156        if (!pw || !pw->pw_dir || sz <= strlen(pw->pw_dir))
 157                return NULL;
 158        baselen = strlen(pw->pw_dir);
 159        memcpy(buf, pw->pw_dir, baselen);
 160        while ((1 < baselen) && (buf[baselen-1] == '/')) {
 161                buf[baselen-1] = 0;
 162                baselen--;
 163        }
 164        if (slash && slash[1]) {
 165                len = strlen(slash);
 166                if (sz <= baselen + len)
 167                        return NULL;
 168                memcpy(buf + baselen, slash, len + 1);
 169        }
 170        return buf;
 171}
 172
 173/*
 174 * First, one directory to try is determined by the following algorithm.
 175 *
 176 * (0) If "strict" is given, the path is used as given and no DWIM is
 177 *     done. Otherwise:
 178 * (1) "~/path" to mean path under the running user's home directory;
 179 * (2) "~user/path" to mean path under named user's home directory;
 180 * (3) "relative/path" to mean cwd relative directory; or
 181 * (4) "/absolute/path" to mean absolute directory.
 182 *
 183 * Unless "strict" is given, we try access() for existence of "%s.git/.git",
 184 * "%s/.git", "%s.git", "%s" in this order.  The first one that exists is
 185 * what we try.
 186 *
 187 * Second, we try chdir() to that.  Upon failure, we return NULL.
 188 *
 189 * Then, we try if the current directory is a valid git repository.
 190 * Upon failure, we return NULL.
 191 *
 192 * If all goes well, we return the directory we used to chdir() (but
 193 * before ~user is expanded), avoiding getcwd() resolving symbolic
 194 * links.  User relative paths are also returned as they are given,
 195 * except DWIM suffixing.
 196 */
 197char *enter_repo(char *path, int strict)
 198{
 199        static char used_path[PATH_MAX];
 200        static char validated_path[PATH_MAX];
 201
 202        if (!path)
 203                return NULL;
 204
 205        if (!strict) {
 206                static const char *suffix[] = {
 207                        ".git/.git", "/.git", ".git", "", NULL,
 208                };
 209                int len = strlen(path);
 210                int i;
 211                while ((1 < len) && (path[len-1] == '/')) {
 212                        path[len-1] = 0;
 213                        len--;
 214                }
 215                if (PATH_MAX <= len)
 216                        return NULL;
 217                if (path[0] == '~') {
 218                        if (!user_path(used_path, path, PATH_MAX))
 219                                return NULL;
 220                        strcpy(validated_path, path);
 221                        path = used_path;
 222                }
 223                else if (PATH_MAX - 10 < len)
 224                        return NULL;
 225                else {
 226                        path = strcpy(used_path, path);
 227                        strcpy(validated_path, path);
 228                }
 229                len = strlen(path);
 230                for (i = 0; suffix[i]; i++) {
 231                        strcpy(path + len, suffix[i]);
 232                        if (!access(path, F_OK)) {
 233                                strcat(validated_path, suffix[i]);
 234                                break;
 235                        }
 236                }
 237                if (!suffix[i] || chdir(path))
 238                        return NULL;
 239                path = validated_path;
 240        }
 241        else if (chdir(path))
 242                return NULL;
 243
 244        if (access("objects", X_OK) == 0 && access("refs", X_OK) == 0 &&
 245            validate_symref("HEAD") == 0) {
 246                putenv("GIT_DIR=.");
 247                check_repository_format();
 248                return path;
 249        }
 250
 251        return NULL;
 252}
 253
 254int adjust_shared_perm(const char *path)
 255{
 256        struct stat st;
 257        int mode;
 258
 259        if (!shared_repository)
 260                return 0;
 261        if (lstat(path, &st) < 0)
 262                return -1;
 263        mode = st.st_mode;
 264        if (mode & S_IRUSR)
 265                mode |= (shared_repository == PERM_GROUP
 266                         ? S_IRGRP
 267                         : (shared_repository == PERM_EVERYBODY
 268                            ? (S_IRGRP|S_IROTH)
 269                            : 0));
 270
 271        if (mode & S_IWUSR)
 272                mode |= S_IWGRP;
 273
 274        if (mode & S_IXUSR)
 275                mode |= (shared_repository == PERM_GROUP
 276                         ? S_IXGRP
 277                         : (shared_repository == PERM_EVERYBODY
 278                            ? (S_IXGRP|S_IXOTH)
 279                            : 0));
 280        if (S_ISDIR(mode))
 281                mode |= S_ISGID;
 282        if (chmod(path, mode) < 0)
 283                return -2;
 284        return 0;
 285}