credential-cache--daemon.con commit Merge branch 'jk/more-push-completion' (0d9cb2d)
   1#include "cache.h"
   2#include "credential.h"
   3#include "unix-socket.h"
   4#include "sigchain.h"
   5
   6static const char *socket_path;
   7
   8static void cleanup_socket(void)
   9{
  10        if (socket_path)
  11                unlink(socket_path);
  12}
  13
  14static void cleanup_socket_on_signal(int sig)
  15{
  16        cleanup_socket();
  17        sigchain_pop(sig);
  18        raise(sig);
  19}
  20
  21struct credential_cache_entry {
  22        struct credential item;
  23        unsigned long expiration;
  24};
  25static struct credential_cache_entry *entries;
  26static int entries_nr;
  27static int entries_alloc;
  28
  29static void cache_credential(struct credential *c, int timeout)
  30{
  31        struct credential_cache_entry *e;
  32
  33        ALLOC_GROW(entries, entries_nr + 1, entries_alloc);
  34        e = &entries[entries_nr++];
  35
  36        /* take ownership of pointers */
  37        memcpy(&e->item, c, sizeof(*c));
  38        memset(c, 0, sizeof(*c));
  39        e->expiration = time(NULL) + timeout;
  40}
  41
  42static struct credential_cache_entry *lookup_credential(const struct credential *c)
  43{
  44        int i;
  45        for (i = 0; i < entries_nr; i++) {
  46                struct credential *e = &entries[i].item;
  47                if (credential_match(c, e))
  48                        return &entries[i];
  49        }
  50        return NULL;
  51}
  52
  53static void remove_credential(const struct credential *c)
  54{
  55        struct credential_cache_entry *e;
  56
  57        e = lookup_credential(c);
  58        if (e)
  59                e->expiration = 0;
  60}
  61
  62static int check_expirations(void)
  63{
  64        static unsigned long wait_for_entry_until;
  65        int i = 0;
  66        unsigned long now = time(NULL);
  67        unsigned long next = (unsigned long)-1;
  68
  69        /*
  70         * Initially give the client 30 seconds to actually contact us
  71         * and store a credential before we decide there's no point in
  72         * keeping the daemon around.
  73         */
  74        if (!wait_for_entry_until)
  75                wait_for_entry_until = now + 30;
  76
  77        while (i < entries_nr) {
  78                if (entries[i].expiration <= now) {
  79                        entries_nr--;
  80                        credential_clear(&entries[i].item);
  81                        if (i != entries_nr)
  82                                memcpy(&entries[i], &entries[entries_nr], sizeof(*entries));
  83                        /*
  84                         * Stick around 30 seconds in case a new credential
  85                         * shows up (e.g., because we just removed a failed
  86                         * one, and we will soon get the correct one).
  87                         */
  88                        wait_for_entry_until = now + 30;
  89                }
  90                else {
  91                        if (entries[i].expiration < next)
  92                                next = entries[i].expiration;
  93                        i++;
  94                }
  95        }
  96
  97        if (!entries_nr) {
  98                if (wait_for_entry_until <= now)
  99                        return 0;
 100                next = wait_for_entry_until;
 101        }
 102
 103        return next - now;
 104}
 105
 106static int read_request(FILE *fh, struct credential *c,
 107                        struct strbuf *action, int *timeout) {
 108        static struct strbuf item = STRBUF_INIT;
 109        const char *p;
 110
 111        strbuf_getline(&item, fh, '\n');
 112        if (!skip_prefix(item.buf, "action=", &p))
 113                return error("client sent bogus action line: %s", item.buf);
 114        strbuf_addstr(action, p);
 115
 116        strbuf_getline(&item, fh, '\n');
 117        if (!skip_prefix(item.buf, "timeout=", &p))
 118                return error("client sent bogus timeout line: %s", item.buf);
 119        *timeout = atoi(p);
 120
 121        if (credential_read(c, fh) < 0)
 122                return -1;
 123        return 0;
 124}
 125
 126static void serve_one_client(FILE *in, FILE *out)
 127{
 128        struct credential c = CREDENTIAL_INIT;
 129        struct strbuf action = STRBUF_INIT;
 130        int timeout = -1;
 131
 132        if (read_request(in, &c, &action, &timeout) < 0)
 133                /* ignore error */ ;
 134        else if (!strcmp(action.buf, "get")) {
 135                struct credential_cache_entry *e = lookup_credential(&c);
 136                if (e) {
 137                        fprintf(out, "username=%s\n", e->item.username);
 138                        fprintf(out, "password=%s\n", e->item.password);
 139                }
 140        }
 141        else if (!strcmp(action.buf, "exit"))
 142                exit(0);
 143        else if (!strcmp(action.buf, "erase"))
 144                remove_credential(&c);
 145        else if (!strcmp(action.buf, "store")) {
 146                if (timeout < 0)
 147                        warning("cache client didn't specify a timeout");
 148                else if (!c.username || !c.password)
 149                        warning("cache client gave us a partial credential");
 150                else {
 151                        remove_credential(&c);
 152                        cache_credential(&c, timeout);
 153                }
 154        }
 155        else
 156                warning("cache client sent unknown action: %s", action.buf);
 157
 158        credential_clear(&c);
 159        strbuf_release(&action);
 160}
 161
 162static int serve_cache_loop(int fd)
 163{
 164        struct pollfd pfd;
 165        unsigned long wakeup;
 166
 167        wakeup = check_expirations();
 168        if (!wakeup)
 169                return 0;
 170
 171        pfd.fd = fd;
 172        pfd.events = POLLIN;
 173        if (poll(&pfd, 1, 1000 * wakeup) < 0) {
 174                if (errno != EINTR)
 175                        die_errno("poll failed");
 176                return 1;
 177        }
 178
 179        if (pfd.revents & POLLIN) {
 180                int client, client2;
 181                FILE *in, *out;
 182
 183                client = accept(fd, NULL, NULL);
 184                if (client < 0) {
 185                        warning("accept failed: %s", strerror(errno));
 186                        return 1;
 187                }
 188                client2 = dup(client);
 189                if (client2 < 0) {
 190                        warning("dup failed: %s", strerror(errno));
 191                        close(client);
 192                        return 1;
 193                }
 194
 195                in = xfdopen(client, "r");
 196                out = xfdopen(client2, "w");
 197                serve_one_client(in, out);
 198                fclose(in);
 199                fclose(out);
 200        }
 201        return 1;
 202}
 203
 204static void serve_cache(const char *socket_path)
 205{
 206        int fd;
 207
 208        fd = unix_stream_listen(socket_path);
 209        if (fd < 0)
 210                die_errno("unable to bind to '%s'", socket_path);
 211
 212        printf("ok\n");
 213        fclose(stdout);
 214
 215        while (serve_cache_loop(fd))
 216                ; /* nothing */
 217
 218        close(fd);
 219        unlink(socket_path);
 220}
 221
 222static const char permissions_advice[] =
 223"The permissions on your socket directory are too loose; other\n"
 224"users may be able to read your cached credentials. Consider running:\n"
 225"\n"
 226"       chmod 0700 %s";
 227static void check_socket_directory(const char *path)
 228{
 229        struct stat st;
 230        char *path_copy = xstrdup(path);
 231        char *dir = dirname(path_copy);
 232
 233        if (!stat(dir, &st)) {
 234                if (st.st_mode & 077)
 235                        die(permissions_advice, dir);
 236                free(path_copy);
 237                return;
 238        }
 239
 240        /*
 241         * We must be sure to create the directory with the correct mode,
 242         * not just chmod it after the fact; otherwise, there is a race
 243         * condition in which somebody can chdir to it, sleep, then try to open
 244         * our protected socket.
 245         */
 246        if (safe_create_leading_directories_const(dir) < 0)
 247                die_errno("unable to create directories for '%s'", dir);
 248        if (mkdir(dir, 0700) < 0)
 249                die_errno("unable to mkdir '%s'", dir);
 250        free(path_copy);
 251}
 252
 253int main(int argc, const char **argv)
 254{
 255        socket_path = argv[1];
 256
 257        if (!socket_path)
 258                die("usage: git-credential-cache--daemon <socket_path>");
 259        check_socket_directory(socket_path);
 260
 261        atexit(cleanup_socket);
 262        sigchain_push_common(cleanup_socket_on_signal);
 263
 264        serve_cache(socket_path);
 265
 266        return 0;
 267}