builtin/merge: honor commit-msg hook for merges
[git] / credential-cache--daemon.c
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
8 static struct tempfile socket_file;
9
10 struct credential_cache_entry {
11         struct credential item;
12         timestamp_t expiration;
13 };
14 static struct credential_cache_entry *entries;
15 static int entries_nr;
16 static int entries_alloc;
17
18 static 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
31 static 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
42 static 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
51 static 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
95 static 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
115 static 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
160 static 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
202 static 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
223 static 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");
228 static 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
261 int 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 }