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Commit | Line | Data |
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a87e8be2 LT |
1 | #include "cache.h" |
2 | #include "pkt-line.h" | |
eaa94919 LT |
3 | #include <signal.h> |
4 | #include <sys/wait.h> | |
a87e8be2 | 5 | #include <sys/socket.h> |
3cd6ecda | 6 | #include <sys/time.h> |
df076bdb | 7 | #include <netdb.h> |
a87e8be2 LT |
8 | #include <netinet/in.h> |
9 | ||
e64e1b79 | 10 | static const char daemon_usage[] = "git-daemon [--inetd | --port=n]"; |
a87e8be2 LT |
11 | |
12 | static int upload(char *dir, int dirlen) | |
13 | { | |
14 | if (chdir(dir) < 0) | |
15 | return -1; | |
16 | chdir(".git"); | |
17 | ||
18 | /* | |
19 | * Security on the cheap. | |
20 | * | |
21 | * We want a readable HEAD, usable "objects" directory, and | |
22 | * a "git-daemon-export-ok" flag that says that the other side | |
23 | * is ok with us doing this. | |
24 | */ | |
25 | if (access("git-daemon-export-ok", F_OK) || | |
26 | access("objects/00", X_OK) || | |
27 | access("HEAD", R_OK)) | |
28 | return -1; | |
29 | ||
02d57da4 LT |
30 | /* |
31 | * We'll ignore SIGTERM from now on, we have a | |
32 | * good client. | |
33 | */ | |
34 | signal(SIGTERM, SIG_IGN); | |
35 | ||
a87e8be2 LT |
36 | /* git-upload-pack only ever reads stuff, so this is safe */ |
37 | execlp("git-upload-pack", "git-upload-pack", ".", NULL); | |
38 | return -1; | |
39 | } | |
40 | ||
7d80694a | 41 | static int execute(void) |
a87e8be2 | 42 | { |
7d80694a LT |
43 | static char line[1000]; |
44 | int len; | |
45 | ||
46 | len = packet_read_line(0, line, sizeof(line)); | |
47 | ||
48 | if (len && line[len-1] == '\n') | |
49 | line[--len] = 0; | |
50 | ||
a87e8be2 LT |
51 | if (!strncmp("git-upload-pack /", line, 17)) |
52 | return upload(line + 16, len - 16); | |
53 | ||
54 | fprintf(stderr, "got bad connection '%s'\n", line); | |
55 | return -1; | |
56 | } | |
57 | ||
66e631de LT |
58 | |
59 | /* | |
60 | * We count spawned/reaped separately, just to avoid any | |
61 | * races when updating them from signals. The SIGCHLD handler | |
62 | * will only update children_reaped, and the fork logic will | |
63 | * only update children_spawned. | |
64 | * | |
65 | * MAX_CHILDREN should be a power-of-two to make the modulus | |
66 | * operation cheap. It should also be at least twice | |
67 | * the maximum number of connections we will ever allow. | |
68 | */ | |
69 | #define MAX_CHILDREN 128 | |
70 | ||
71 | static int max_connections = 25; | |
72 | ||
73 | /* These are updated by the signal handler */ | |
74 | static volatile unsigned int children_reaped = 0; | |
4d8fa916 | 75 | static pid_t dead_child[MAX_CHILDREN]; |
66e631de LT |
76 | |
77 | /* These are updated by the main loop */ | |
78 | static unsigned int children_spawned = 0; | |
79 | static unsigned int children_deleted = 0; | |
80 | ||
4d8fa916 | 81 | static struct child { |
66e631de | 82 | pid_t pid; |
7fa09084 | 83 | int addrlen; |
df076bdb | 84 | struct sockaddr_storage address; |
66e631de LT |
85 | } live_child[MAX_CHILDREN]; |
86 | ||
7fa09084 | 87 | static void add_child(int idx, pid_t pid, struct sockaddr *addr, int addrlen) |
66e631de LT |
88 | { |
89 | live_child[idx].pid = pid; | |
90 | live_child[idx].addrlen = addrlen; | |
df076bdb | 91 | memcpy(&live_child[idx].address, addr, addrlen); |
66e631de LT |
92 | } |
93 | ||
94 | /* | |
95 | * Walk from "deleted" to "spawned", and remove child "pid". | |
96 | * | |
97 | * We move everything up by one, since the new "deleted" will | |
98 | * be one higher. | |
99 | */ | |
100 | static void remove_child(pid_t pid, unsigned deleted, unsigned spawned) | |
101 | { | |
102 | struct child n; | |
103 | ||
104 | deleted %= MAX_CHILDREN; | |
105 | spawned %= MAX_CHILDREN; | |
106 | if (live_child[deleted].pid == pid) { | |
107 | live_child[deleted].pid = -1; | |
108 | return; | |
109 | } | |
110 | n = live_child[deleted]; | |
111 | for (;;) { | |
112 | struct child m; | |
113 | deleted = (deleted + 1) % MAX_CHILDREN; | |
114 | if (deleted == spawned) | |
115 | die("could not find dead child %d\n", pid); | |
116 | m = live_child[deleted]; | |
117 | live_child[deleted] = n; | |
118 | if (m.pid == pid) | |
119 | return; | |
120 | n = m; | |
121 | } | |
122 | } | |
123 | ||
124 | /* | |
125 | * This gets called if the number of connections grows | |
126 | * past "max_connections". | |
127 | * | |
128 | * We _should_ start off by searching for connections | |
129 | * from the same IP, and if there is some address wth | |
130 | * multiple connections, we should kill that first. | |
131 | * | |
132 | * As it is, we just "randomly" kill 25% of the connections, | |
133 | * and our pseudo-random generator sucks too. I have no | |
134 | * shame. | |
135 | * | |
136 | * Really, this is just a place-holder for a _real_ algorithm. | |
137 | */ | |
02d57da4 | 138 | static void kill_some_children(int signo, unsigned start, unsigned stop) |
66e631de LT |
139 | { |
140 | start %= MAX_CHILDREN; | |
141 | stop %= MAX_CHILDREN; | |
142 | while (start != stop) { | |
143 | if (!(start & 3)) | |
02d57da4 | 144 | kill(live_child[start].pid, signo); |
66e631de LT |
145 | start = (start + 1) % MAX_CHILDREN; |
146 | } | |
147 | } | |
148 | ||
02d57da4 | 149 | static void check_max_connections(void) |
a87e8be2 | 150 | { |
02d57da4 | 151 | for (;;) { |
eaa94919 | 152 | int active; |
66e631de | 153 | unsigned spawned, reaped, deleted; |
eaa94919 | 154 | |
66e631de | 155 | spawned = children_spawned; |
66e631de LT |
156 | reaped = children_reaped; |
157 | deleted = children_deleted; | |
158 | ||
159 | while (deleted < reaped) { | |
160 | pid_t pid = dead_child[deleted % MAX_CHILDREN]; | |
161 | remove_child(pid, deleted, spawned); | |
162 | deleted++; | |
163 | } | |
164 | children_deleted = deleted; | |
165 | ||
166 | active = spawned - deleted; | |
02d57da4 LT |
167 | if (active <= max_connections) |
168 | break; | |
66e631de | 169 | |
02d57da4 LT |
170 | /* Kill some unstarted connections with SIGTERM */ |
171 | kill_some_children(SIGTERM, deleted, spawned); | |
172 | if (active <= max_connections << 1) | |
173 | break; | |
174 | ||
175 | /* If the SIGTERM thing isn't helping use SIGKILL */ | |
176 | kill_some_children(SIGKILL, deleted, spawned); | |
177 | sleep(1); | |
178 | } | |
179 | } | |
180 | ||
7fa09084 | 181 | static void handle(int incoming, struct sockaddr *addr, int addrlen) |
02d57da4 LT |
182 | { |
183 | pid_t pid = fork(); | |
184 | ||
185 | if (pid) { | |
186 | unsigned idx; | |
187 | ||
188 | close(incoming); | |
189 | if (pid < 0) | |
190 | return; | |
191 | ||
192 | idx = children_spawned % MAX_CHILDREN; | |
193 | children_spawned++; | |
194 | add_child(idx, pid, addr, addrlen); | |
66e631de | 195 | |
02d57da4 | 196 | check_max_connections(); |
a87e8be2 LT |
197 | return; |
198 | } | |
199 | ||
200 | dup2(incoming, 0); | |
201 | dup2(incoming, 1); | |
202 | close(incoming); | |
7d80694a | 203 | exit(execute()); |
a87e8be2 LT |
204 | } |
205 | ||
eaa94919 LT |
206 | static void child_handler(int signo) |
207 | { | |
208 | for (;;) { | |
66e631de LT |
209 | pid_t pid = waitpid(-1, NULL, WNOHANG); |
210 | ||
211 | if (pid > 0) { | |
212 | unsigned reaped = children_reaped; | |
213 | dead_child[reaped % MAX_CHILDREN] = pid; | |
214 | children_reaped = reaped + 1; | |
eaa94919 LT |
215 | continue; |
216 | } | |
217 | break; | |
218 | } | |
219 | } | |
220 | ||
a87e8be2 LT |
221 | static int serve(int port) |
222 | { | |
df076bdb YH |
223 | struct addrinfo hints, *ai0, *ai; |
224 | int gai; | |
225 | int socknum = 0, *socklist = NULL; | |
226 | int maxfd = -1; | |
227 | fd_set fds_init, fds; | |
228 | char pbuf[NI_MAXSERV]; | |
a87e8be2 | 229 | |
eaa94919 | 230 | signal(SIGCHLD, child_handler); |
df076bdb YH |
231 | |
232 | sprintf(pbuf, "%d", port); | |
233 | memset(&hints, 0, sizeof(hints)); | |
234 | hints.ai_family = AF_UNSPEC; | |
235 | hints.ai_socktype = SOCK_STREAM; | |
236 | hints.ai_protocol = IPPROTO_TCP; | |
237 | hints.ai_flags = AI_PASSIVE; | |
238 | ||
239 | gai = getaddrinfo(NULL, pbuf, &hints, &ai0); | |
240 | if (gai) | |
241 | die("getaddrinfo() failed: %s\n", gai_strerror(gai)); | |
242 | ||
243 | FD_ZERO(&fds_init); | |
244 | ||
245 | for (ai = ai0; ai; ai = ai->ai_next) { | |
246 | int sockfd; | |
247 | int *newlist; | |
248 | ||
249 | sockfd = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol); | |
250 | if (sockfd < 0) | |
251 | continue; | |
252 | if (sockfd >= FD_SETSIZE) { | |
253 | error("too large socket descriptor."); | |
254 | close(sockfd); | |
255 | continue; | |
256 | } | |
257 | ||
258 | #ifdef IPV6_V6ONLY | |
259 | if (ai->ai_family == AF_INET6) { | |
260 | int on = 1; | |
261 | setsockopt(sockfd, IPPROTO_IPV6, IPV6_V6ONLY, | |
262 | &on, sizeof(on)); | |
263 | /* Note: error is not fatal */ | |
264 | } | |
265 | #endif | |
266 | ||
267 | if (bind(sockfd, ai->ai_addr, ai->ai_addrlen) < 0) { | |
268 | close(sockfd); | |
269 | continue; /* not fatal */ | |
270 | } | |
271 | if (listen(sockfd, 5) < 0) { | |
272 | close(sockfd); | |
273 | continue; /* not fatal */ | |
274 | } | |
275 | ||
276 | newlist = realloc(socklist, sizeof(int) * (socknum + 1)); | |
277 | if (!newlist) | |
278 | die("memory allocation failed: %s", strerror(errno)); | |
279 | ||
280 | socklist = newlist; | |
281 | socklist[socknum++] = sockfd; | |
282 | ||
283 | FD_SET(sockfd, &fds_init); | |
284 | if (maxfd < sockfd) | |
285 | maxfd = sockfd; | |
286 | } | |
287 | ||
288 | freeaddrinfo(ai0); | |
289 | ||
290 | if (socknum == 0) | |
291 | die("unable to allocate any listen sockets on port %u", port); | |
a87e8be2 LT |
292 | |
293 | for (;;) { | |
df076bdb YH |
294 | int i; |
295 | fds = fds_init; | |
296 | ||
297 | if (select(maxfd + 1, &fds, NULL, NULL, NULL) < 0) { | |
1eef0b33 JH |
298 | if (errno != EINTR) { |
299 | error("select failed, resuming: %s", | |
300 | strerror(errno)); | |
301 | sleep(1); | |
302 | } | |
df076bdb YH |
303 | continue; |
304 | } | |
305 | ||
306 | for (i = 0; i < socknum; i++) { | |
307 | int sockfd = socklist[i]; | |
308 | ||
309 | if (FD_ISSET(sockfd, &fds)) { | |
310 | struct sockaddr_storage ss; | |
7fa09084 | 311 | int sslen = sizeof(ss); |
df076bdb YH |
312 | int incoming = accept(sockfd, (struct sockaddr *)&ss, &sslen); |
313 | if (incoming < 0) { | |
314 | switch (errno) { | |
315 | case EAGAIN: | |
316 | case EINTR: | |
317 | case ECONNABORTED: | |
318 | continue; | |
319 | default: | |
320 | die("accept returned %s", strerror(errno)); | |
321 | } | |
322 | } | |
323 | handle(incoming, (struct sockaddr *)&ss, sslen); | |
a87e8be2 LT |
324 | } |
325 | } | |
a87e8be2 LT |
326 | } |
327 | } | |
328 | ||
329 | int main(int argc, char **argv) | |
330 | { | |
331 | int port = DEFAULT_GIT_PORT; | |
e64e1b79 | 332 | int inetd_mode = 0; |
a87e8be2 LT |
333 | int i; |
334 | ||
335 | for (i = 1; i < argc; i++) { | |
336 | char *arg = argv[i]; | |
337 | ||
338 | if (!strncmp(arg, "--port=", 7)) { | |
339 | char *end; | |
340 | unsigned long n; | |
341 | n = strtoul(arg+7, &end, 0); | |
342 | if (arg[7] && !*end) { | |
343 | port = n; | |
344 | continue; | |
345 | } | |
346 | } | |
e64e1b79 LT |
347 | |
348 | if (!strcmp(arg, "--inetd")) { | |
349 | inetd_mode = 1; | |
350 | continue; | |
351 | } | |
352 | ||
a87e8be2 LT |
353 | usage(daemon_usage); |
354 | } | |
355 | ||
7c3693f1 LD |
356 | if (inetd_mode) { |
357 | fclose(stderr); //FIXME: workaround | |
e64e1b79 | 358 | return execute(); |
7c3693f1 | 359 | } |
e64e1b79 | 360 | |
a87e8be2 LT |
361 | return serve(port); |
362 | } |