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