credential-cache--daemon.con commit Merge branch 'sb/submodule-parallel-update' (4add209)
   1#include "cache.h"
   2#include "config.h"
   3#include "tempfile.h"
   4#include "credential.h"
   5#include "unix-socket.h"
   6#include "parse-options.h"
   7
   8static struct tempfile socket_file;
   9
  10struct credential_cache_entry {
  11        struct credential item;
  12        timestamp_t expiration;
  13};
  14static struct credential_cache_entry *entries;
  15static int entries_nr;
  16static int entries_alloc;
  17
  18static void cache_credential(struct credential *c, int timeout)
  19{
  20        struct credential_cache_entry *e;
  21
  22        ALLOC_GROW(entries, entries_nr + 1, entries_alloc);
  23        e = &entries[entries_nr++];
  24
  25        /* take ownership of pointers */
  26        memcpy(&e->item, c, sizeof(*c));
  27        memset(c, 0, sizeof(*c));
  28        e->expiration = time(NULL) + timeout;
  29}
  30
  31static struct credential_cache_entry *lookup_credential(const struct credential *c)
  32{
  33        int i;
  34        for (i = 0; i < entries_nr; i++) {
  35                struct credential *e = &entries[i].item;
  36                if (credential_match(c, e))
  37                        return &entries[i];
  38        }
  39        return NULL;
  40}
  41
  42static void remove_credential(const struct credential *c)
  43{
  44        struct credential_cache_entry *e;
  45
  46        e = lookup_credential(c);
  47        if (e)
  48                e->expiration = 0;
  49}
  50
  51static timestamp_t check_expirations(void)
  52{
  53        static timestamp_t wait_for_entry_until;
  54        int i = 0;
  55        timestamp_t now = time(NULL);
  56        timestamp_t next = TIME_MAX;
  57
  58        /*
  59         * Initially give the client 30 seconds to actually contact us
  60         * and store a credential before we decide there's no point in
  61         * keeping the daemon around.
  62         */
  63        if (!wait_for_entry_until)
  64                wait_for_entry_until = now + 30;
  65
  66        while (i < entries_nr) {
  67                if (entries[i].expiration <= now) {
  68                        entries_nr--;
  69                        credential_clear(&entries[i].item);
  70                        if (i != entries_nr)
  71                                memcpy(&entries[i], &entries[entries_nr], sizeof(*entries));
  72                        /*
  73                         * Stick around 30 seconds in case a new credential
  74                         * shows up (e.g., because we just removed a failed
  75                         * one, and we will soon get the correct one).
  76                         */
  77                        wait_for_entry_until = now + 30;
  78                }
  79                else {
  80                        if (entries[i].expiration < next)
  81                                next = entries[i].expiration;
  82                        i++;
  83                }
  84        }
  85
  86        if (!entries_nr) {
  87                if (wait_for_entry_until <= now)
  88                        return 0;
  89                next = wait_for_entry_until;
  90        }
  91
  92        return next - now;
  93}
  94
  95static int read_request(FILE *fh, struct credential *c,
  96                        struct strbuf *action, int *timeout) {
  97        static struct strbuf item = STRBUF_INIT;
  98        const char *p;
  99
 100        strbuf_getline_lf(&item, fh);
 101        if (!skip_prefix(item.buf, "action=", &p))
 102                return error("client sent bogus action line: %s", item.buf);
 103        strbuf_addstr(action, p);
 104
 105        strbuf_getline_lf(&item, fh);
 106        if (!skip_prefix(item.buf, "timeout=", &p))
 107                return error("client sent bogus timeout line: %s", item.buf);
 108        *timeout = atoi(p);
 109
 110        if (credential_read(c, fh) < 0)
 111                return -1;
 112        return 0;
 113}
 114
 115static void serve_one_client(FILE *in, FILE *out)
 116{
 117        struct credential c = CREDENTIAL_INIT;
 118        struct strbuf action = STRBUF_INIT;
 119        int timeout = -1;
 120
 121        if (read_request(in, &c, &action, &timeout) < 0)
 122                /* ignore error */ ;
 123        else if (!strcmp(action.buf, "get")) {
 124                struct credential_cache_entry *e = lookup_credential(&c);
 125                if (e) {
 126                        fprintf(out, "username=%s\n", e->item.username);
 127                        fprintf(out, "password=%s\n", e->item.password);
 128                }
 129        }
 130        else if (!strcmp(action.buf, "exit")) {
 131                /*
 132                 * It's important that we clean up our socket first, and then
 133                 * signal the client only once we have finished the cleanup.
 134                 * Calling exit() directly does this, because we clean up in
 135                 * our atexit() handler, and then signal the client when our
 136                 * process actually ends, which closes the socket and gives
 137                 * them EOF.
 138                 */
 139                exit(0);
 140        }
 141        else if (!strcmp(action.buf, "erase"))
 142                remove_credential(&c);
 143        else if (!strcmp(action.buf, "store")) {
 144                if (timeout < 0)
 145                        warning("cache client didn't specify a timeout");
 146                else if (!c.username || !c.password)
 147                        warning("cache client gave us a partial credential");
 148                else {
 149                        remove_credential(&c);
 150                        cache_credential(&c, timeout);
 151                }
 152        }
 153        else
 154                warning("cache client sent unknown action: %s", action.buf);
 155
 156        credential_clear(&c);
 157        strbuf_release(&action);
 158}
 159
 160static int serve_cache_loop(int fd)
 161{
 162        struct pollfd pfd;
 163        timestamp_t wakeup;
 164
 165        wakeup = check_expirations();
 166        if (!wakeup)
 167                return 0;
 168
 169        pfd.fd = fd;
 170        pfd.events = POLLIN;
 171        if (poll(&pfd, 1, 1000 * wakeup) < 0) {
 172                if (errno != EINTR)
 173                        die_errno("poll failed");
 174                return 1;
 175        }
 176
 177        if (pfd.revents & POLLIN) {
 178                int client, client2;
 179                FILE *in, *out;
 180
 181                client = accept(fd, NULL, NULL);
 182                if (client < 0) {
 183                        warning_errno("accept failed");
 184                        return 1;
 185                }
 186                client2 = dup(client);
 187                if (client2 < 0) {
 188                        warning_errno("dup failed");
 189                        close(client);
 190                        return 1;
 191                }
 192
 193                in = xfdopen(client, "r");
 194                out = xfdopen(client2, "w");
 195                serve_one_client(in, out);
 196                fclose(in);
 197                fclose(out);
 198        }
 199        return 1;
 200}
 201
 202static void serve_cache(const char *socket_path, int debug)
 203{
 204        int fd;
 205
 206        fd = unix_stream_listen(socket_path);
 207        if (fd < 0)
 208                die_errno("unable to bind to '%s'", socket_path);
 209
 210        printf("ok\n");
 211        fclose(stdout);
 212        if (!debug) {
 213                if (!freopen("/dev/null", "w", stderr))
 214                        die_errno("unable to point stderr to /dev/null");
 215        }
 216
 217        while (serve_cache_loop(fd))
 218                ; /* nothing */
 219
 220        close(fd);
 221}
 222
 223static const char permissions_advice[] = N_(
 224"The permissions on your socket directory are too loose; other\n"
 225"users may be able to read your cached credentials. Consider running:\n"
 226"\n"
 227"       chmod 0700 %s");
 228static void init_socket_directory(const char *path)
 229{
 230        struct stat st;
 231        char *path_copy = xstrdup(path);
 232        char *dir = dirname(path_copy);
 233
 234        if (!stat(dir, &st)) {
 235                if (st.st_mode & 077)
 236                        die(_(permissions_advice), dir);
 237        } else {
 238                /*
 239                 * We must be sure to create the directory with the correct mode,
 240                 * not just chmod it after the fact; otherwise, there is a race
 241                 * condition in which somebody can chdir to it, sleep, then try to open
 242                 * our protected socket.
 243                 */
 244                if (safe_create_leading_directories_const(dir) < 0)
 245                        die_errno("unable to create directories for '%s'", dir);
 246                if (mkdir(dir, 0700) < 0)
 247                        die_errno("unable to mkdir '%s'", dir);
 248        }
 249
 250        if (chdir(dir))
 251                /*
 252                 * We don't actually care what our cwd is; we chdir here just to
 253                 * be a friendly daemon and avoid tying up our original cwd.
 254                 * If this fails, it's OK to just continue without that benefit.
 255                 */
 256                ;
 257
 258        free(path_copy);
 259}
 260
 261int cmd_main(int argc, const char **argv)
 262{
 263        const char *socket_path;
 264        int ignore_sighup = 0;
 265        static const char *usage[] = {
 266                "git-credential-cache--daemon [opts] <socket_path>",
 267                NULL
 268        };
 269        int debug = 0;
 270        const struct option options[] = {
 271                OPT_BOOL(0, "debug", &debug,
 272                         N_("print debugging messages to stderr")),
 273                OPT_END()
 274        };
 275
 276        git_config_get_bool("credentialcache.ignoresighup", &ignore_sighup);
 277
 278        argc = parse_options(argc, argv, NULL, options, usage, 0);
 279        socket_path = argv[0];
 280
 281        if (!socket_path)
 282                usage_with_options(usage, options);
 283
 284        if (!is_absolute_path(socket_path))
 285                die("socket directory must be an absolute path");
 286
 287        init_socket_directory(socket_path);
 288        register_tempfile(&socket_file, socket_path);
 289
 290        if (ignore_sighup)
 291                signal(SIGHUP, SIG_IGN);
 292
 293        serve_cache(socket_path, debug);
 294        delete_tempfile(&socket_file);
 295
 296        return 0;
 297}