Documentation: Transplanting branch with git-rebase --onto
[git] / upload-pack.c
1 #include <signal.h>
2 #include <sys/wait.h>
3 #include <sys/poll.h>
4 #include "cache.h"
5 #include "refs.h"
6 #include "pkt-line.h"
7 #include "sideband.h"
8 #include "tag.h"
9 #include "object.h"
10 #include "commit.h"
11 #include "exec_cmd.h"
12
13 static const char upload_pack_usage[] = "git-upload-pack [--strict] [--timeout=nn] <dir>";
14
15 #define THEY_HAVE (1U << 0)
16 #define OUR_REF (1U << 1)
17 #define WANTED (1U << 2)
18 static int multi_ack, nr_our_refs;
19 static int use_thin_pack;
20 static struct object_array have_obj;
21 static struct object_array want_obj;
22 static unsigned int timeout;
23 /* 0 for no sideband,
24  * otherwise maximum packet size (up to 65520 bytes).
25  */
26 static int use_sideband;
27
28 static void reset_timeout(void)
29 {
30         alarm(timeout);
31 }
32
33 static int strip(char *line, int len)
34 {
35         if (len && line[len-1] == '\n')
36                 line[--len] = 0;
37         return len;
38 }
39
40 static ssize_t send_client_data(int fd, const char *data, ssize_t sz)
41 {
42         if (use_sideband)
43                 return send_sideband(1, fd, data, sz, use_sideband);
44         if (fd == 3)
45                 /* emergency quit */
46                 fd = 2;
47         if (fd == 2) {
48                 xwrite(fd, data, sz);
49                 return sz;
50         }
51         return safe_write(fd, data, sz);
52 }
53
54 static void create_pack_file(void)
55 {
56         /* Pipes between rev-list to pack-objects, pack-objects to us
57          * and pack-objects error stream for progress bar.
58          */
59         int lp_pipe[2], pu_pipe[2], pe_pipe[2];
60         pid_t pid_rev_list, pid_pack_objects;
61         int create_full_pack = (nr_our_refs == want_obj.nr && !have_obj.nr);
62         char data[8193], progress[128];
63         char abort_msg[] = "aborting due to possible repository "
64                 "corruption on the remote side.";
65         int buffered = -1;
66
67         if (pipe(lp_pipe) < 0)
68                 die("git-upload-pack: unable to create pipe");
69         pid_rev_list = fork();
70         if (pid_rev_list < 0)
71                 die("git-upload-pack: unable to fork git-rev-list");
72
73         if (!pid_rev_list) {
74                 int i;
75                 int args;
76                 const char **argv;
77                 const char **p;
78                 char *buf;
79
80                 if (create_full_pack) {
81                         args = 10;
82                         use_thin_pack = 0; /* no point doing it */
83                 }
84                 else
85                         args = have_obj.nr + want_obj.nr + 5;
86                 p = xmalloc(args * sizeof(char *));
87                 argv = (const char **) p;
88                 buf = xmalloc(args * 45);
89
90                 dup2(lp_pipe[1], 1);
91                 close(0);
92                 close(lp_pipe[0]);
93                 close(lp_pipe[1]);
94                 *p++ = "rev-list";
95                 *p++ = use_thin_pack ? "--objects-edge" : "--objects";
96                 if (create_full_pack)
97                         *p++ = "--all";
98                 else {
99                         for (i = 0; i < want_obj.nr; i++) {
100                                 struct object *o = want_obj.objects[i].item;
101                                 *p++ = buf;
102                                 memcpy(buf, sha1_to_hex(o->sha1), 41);
103                                 buf += 41;
104                         }
105                 }
106                 if (!create_full_pack)
107                         for (i = 0; i < have_obj.nr; i++) {
108                                 struct object *o = have_obj.objects[i].item;
109                                 *p++ = buf;
110                                 *buf++ = '^';
111                                 memcpy(buf, sha1_to_hex(o->sha1), 41);
112                                 buf += 41;
113                         }
114                 *p++ = NULL;
115                 execv_git_cmd(argv);
116                 die("git-upload-pack: unable to exec git-rev-list");
117         }
118
119         if (pipe(pu_pipe) < 0)
120                 die("git-upload-pack: unable to create pipe");
121         if (pipe(pe_pipe) < 0)
122                 die("git-upload-pack: unable to create pipe");
123         pid_pack_objects = fork();
124         if (pid_pack_objects < 0) {
125                 /* daemon sets things up to ignore TERM */
126                 kill(pid_rev_list, SIGKILL);
127                 die("git-upload-pack: unable to fork git-pack-objects");
128         }
129         if (!pid_pack_objects) {
130                 dup2(lp_pipe[0], 0);
131                 dup2(pu_pipe[1], 1);
132                 dup2(pe_pipe[1], 2);
133
134                 close(lp_pipe[0]);
135                 close(lp_pipe[1]);
136                 close(pu_pipe[0]);
137                 close(pu_pipe[1]);
138                 close(pe_pipe[0]);
139                 close(pe_pipe[1]);
140                 execl_git_cmd("pack-objects", "--stdout", "--progress", NULL);
141                 kill(pid_rev_list, SIGKILL);
142                 die("git-upload-pack: unable to exec git-pack-objects");
143         }
144
145         close(lp_pipe[0]);
146         close(lp_pipe[1]);
147
148         /* We read from pe_pipe[0] to capture stderr output for
149          * progress bar, and pu_pipe[0] to capture the pack data.
150          */
151         close(pe_pipe[1]);
152         close(pu_pipe[1]);
153
154         while (1) {
155                 const char *who;
156                 struct pollfd pfd[2];
157                 pid_t pid;
158                 int status;
159                 ssize_t sz;
160                 int pe, pu, pollsize;
161
162                 reset_timeout();
163
164                 pollsize = 0;
165                 pe = pu = -1;
166
167                 if (0 <= pu_pipe[0]) {
168                         pfd[pollsize].fd = pu_pipe[0];
169                         pfd[pollsize].events = POLLIN;
170                         pu = pollsize;
171                         pollsize++;
172                 }
173                 if (0 <= pe_pipe[0]) {
174                         pfd[pollsize].fd = pe_pipe[0];
175                         pfd[pollsize].events = POLLIN;
176                         pe = pollsize;
177                         pollsize++;
178                 }
179
180                 if (pollsize) {
181                         if (poll(pfd, pollsize, -1) < 0) {
182                                 if (errno != EINTR) {
183                                         error("poll failed, resuming: %s",
184                                               strerror(errno));
185                                         sleep(1);
186                                 }
187                                 continue;
188                         }
189                         if (0 <= pu && (pfd[pu].revents & (POLLIN|POLLHUP))) {
190                                 /* Data ready; we keep the last byte
191                                  * to ourselves in case we detect
192                                  * broken rev-list, so that we can
193                                  * leave the stream corrupted.  This
194                                  * is unfortunate -- unpack-objects
195                                  * would happily accept a valid pack
196                                  * data with trailing garbage, so
197                                  * appending garbage after we pass all
198                                  * the pack data is not good enough to
199                                  * signal breakage to downstream.
200                                  */
201                                 char *cp = data;
202                                 ssize_t outsz = 0;
203                                 if (0 <= buffered) {
204                                         *cp++ = buffered;
205                                         outsz++;
206                                 }
207                                 sz = read(pu_pipe[0], cp,
208                                           sizeof(data) - outsz);
209                                 if (0 < sz)
210                                                 ;
211                                 else if (sz == 0) {
212                                         close(pu_pipe[0]);
213                                         pu_pipe[0] = -1;
214                                 }
215                                 else
216                                         goto fail;
217                                 sz += outsz;
218                                 if (1 < sz) {
219                                         buffered = data[sz-1] & 0xFF;
220                                         sz--;
221                                 }
222                                 else
223                                         buffered = -1;
224                                 sz = send_client_data(1, data, sz);
225                                 if (sz < 0)
226                                         goto fail;
227                         }
228                         if (0 <= pe && (pfd[pe].revents & (POLLIN|POLLHUP))) {
229                                 /* Status ready; we ship that in the side-band
230                                  * or dump to the standard error.
231                                  */
232                                 sz = read(pe_pipe[0], progress,
233                                           sizeof(progress));
234                                 if (0 < sz)
235                                         send_client_data(2, progress, sz);
236                                 else if (sz == 0) {
237                                         close(pe_pipe[0]);
238                                         pe_pipe[0] = -1;
239                                 }
240                                 else
241                                         goto fail;
242                         }
243                 }
244
245                 /* See if the children are still there */
246                 if (pid_rev_list || pid_pack_objects) {
247                         pid = waitpid(-1, &status, WNOHANG);
248                         if (!pid)
249                                 continue;
250                         who = ((pid == pid_rev_list) ? "git-rev-list" :
251                                (pid == pid_pack_objects) ? "git-pack-objects" :
252                                NULL);
253                         if (!who) {
254                                 if (pid < 0) {
255                                         error("git-upload-pack: %s",
256                                               strerror(errno));
257                                         goto fail;
258                                 }
259                                 error("git-upload-pack: we weren't "
260                                       "waiting for %d", pid);
261                                 continue;
262                         }
263                         if (!WIFEXITED(status) || WEXITSTATUS(status) > 0) {
264                                 error("git-upload-pack: %s died with error.",
265                                       who);
266                                 goto fail;
267                         }
268                         if (pid == pid_rev_list)
269                                 pid_rev_list = 0;
270                         if (pid == pid_pack_objects)
271                                 pid_pack_objects = 0;
272                         if (pid_rev_list || pid_pack_objects)
273                                 continue;
274                 }
275
276                 /* both died happily */
277                 if (pollsize)
278                         continue;
279
280                 /* flush the data */
281                 if (0 <= buffered) {
282                         data[0] = buffered;
283                         sz = send_client_data(1, data, 1);
284                         if (sz < 0)
285                                 goto fail;
286                         fprintf(stderr, "flushed.\n");
287                 }
288                 if (use_sideband)
289                         packet_flush(1);
290                 return;
291         }
292  fail:
293         if (pid_pack_objects)
294                 kill(pid_pack_objects, SIGKILL);
295         if (pid_rev_list)
296                 kill(pid_rev_list, SIGKILL);
297         send_client_data(3, abort_msg, sizeof(abort_msg));
298         die("git-upload-pack: %s", abort_msg);
299 }
300
301 static int got_sha1(char *hex, unsigned char *sha1)
302 {
303         struct object *o;
304
305         if (get_sha1_hex(hex, sha1))
306                 die("git-upload-pack: expected SHA1 object, got '%s'", hex);
307         if (!has_sha1_file(sha1))
308                 return 0;
309
310         o = lookup_object(sha1);
311         if (!(o && o->parsed))
312                 o = parse_object(sha1);
313         if (!o)
314                 die("oops (%s)", sha1_to_hex(sha1));
315         if (o->type == OBJ_COMMIT) {
316                 struct commit_list *parents;
317                 if (o->flags & THEY_HAVE)
318                         return 0;
319                 o->flags |= THEY_HAVE;
320                 for (parents = ((struct commit*)o)->parents;
321                      parents;
322                      parents = parents->next)
323                         parents->item->object.flags |= THEY_HAVE;
324         }
325         add_object_array(o, NULL, &have_obj);
326         return 1;
327 }
328
329 static int get_common_commits(void)
330 {
331         static char line[1000];
332         unsigned char sha1[20];
333         char hex[41], last_hex[41];
334         int len;
335
336         track_object_refs = 0;
337         save_commit_buffer = 0;
338
339         for(;;) {
340                 len = packet_read_line(0, line, sizeof(line));
341                 reset_timeout();
342
343                 if (!len) {
344                         if (have_obj.nr == 0 || multi_ack)
345                                 packet_write(1, "NAK\n");
346                         continue;
347                 }
348                 len = strip(line, len);
349                 if (!strncmp(line, "have ", 5)) {
350                         if (got_sha1(line+5, sha1)) {
351                                 memcpy(hex, sha1_to_hex(sha1), 41);
352                                 if (multi_ack) {
353                                         const char *msg = "ACK %s continue\n";
354                                         packet_write(1, msg, hex);
355                                         memcpy(last_hex, hex, 41);
356                                 }
357                                 else if (have_obj.nr == 1)
358                                         packet_write(1, "ACK %s\n", hex);
359                         }
360                         continue;
361                 }
362                 if (!strcmp(line, "done")) {
363                         if (have_obj.nr > 0) {
364                                 if (multi_ack)
365                                         packet_write(1, "ACK %s\n", last_hex);
366                                 return 0;
367                         }
368                         packet_write(1, "NAK\n");
369                         return -1;
370                 }
371                 die("git-upload-pack: expected SHA1 list, got '%s'", line);
372         }
373 }
374
375 static void receive_needs(void)
376 {
377         static char line[1000];
378         int len;
379
380         for (;;) {
381                 struct object *o;
382                 unsigned char sha1_buf[20];
383                 len = packet_read_line(0, line, sizeof(line));
384                 reset_timeout();
385                 if (!len)
386                         return;
387
388                 if (strncmp("want ", line, 5) ||
389                     get_sha1_hex(line+5, sha1_buf))
390                         die("git-upload-pack: protocol error, "
391                             "expected to get sha, not '%s'", line);
392                 if (strstr(line+45, "multi_ack"))
393                         multi_ack = 1;
394                 if (strstr(line+45, "thin-pack"))
395                         use_thin_pack = 1;
396                 if (strstr(line+45, "side-band-64k"))
397                         use_sideband = LARGE_PACKET_MAX;
398                 else if (strstr(line+45, "side-band"))
399                         use_sideband = DEFAULT_PACKET_MAX;
400
401                 /* We have sent all our refs already, and the other end
402                  * should have chosen out of them; otherwise they are
403                  * asking for nonsense.
404                  *
405                  * Hmph.  We may later want to allow "want" line that
406                  * asks for something like "master~10" (symbolic)...
407                  * would it make sense?  I don't know.
408                  */
409                 o = lookup_object(sha1_buf);
410                 if (!o || !(o->flags & OUR_REF))
411                         die("git-upload-pack: not our ref %s", line+5);
412                 if (!(o->flags & WANTED)) {
413                         o->flags |= WANTED;
414                         add_object_array(o, NULL, &want_obj);
415                 }
416         }
417 }
418
419 static int send_ref(const char *refname, const unsigned char *sha1)
420 {
421         static const char *capabilities = "multi_ack thin-pack side-band side-band-64k";
422         struct object *o = parse_object(sha1);
423
424         if (!o)
425                 die("git-upload-pack: cannot find object %s:", sha1_to_hex(sha1));
426
427         if (capabilities)
428                 packet_write(1, "%s %s%c%s\n", sha1_to_hex(sha1), refname,
429                         0, capabilities);
430         else
431                 packet_write(1, "%s %s\n", sha1_to_hex(sha1), refname);
432         capabilities = NULL;
433         if (!(o->flags & OUR_REF)) {
434                 o->flags |= OUR_REF;
435                 nr_our_refs++;
436         }
437         if (o->type == OBJ_TAG) {
438                 o = deref_tag(o, refname, 0);
439                 packet_write(1, "%s %s^{}\n", sha1_to_hex(o->sha1), refname);
440         }
441         return 0;
442 }
443
444 static void upload_pack(void)
445 {
446         reset_timeout();
447         head_ref(send_ref);
448         for_each_ref(send_ref);
449         packet_flush(1);
450         receive_needs();
451         if (want_obj.nr) {
452                 get_common_commits();
453                 create_pack_file();
454         }
455 }
456
457 int main(int argc, char **argv)
458 {
459         char *dir;
460         int i;
461         int strict = 0;
462
463         for (i = 1; i < argc; i++) {
464                 char *arg = argv[i];
465
466                 if (arg[0] != '-')
467                         break;
468                 if (!strcmp(arg, "--strict")) {
469                         strict = 1;
470                         continue;
471                 }
472                 if (!strncmp(arg, "--timeout=", 10)) {
473                         timeout = atoi(arg+10);
474                         continue;
475                 }
476                 if (!strcmp(arg, "--")) {
477                         i++;
478                         break;
479                 }
480         }
481         
482         if (i != argc-1)
483                 usage(upload_pack_usage);
484         dir = argv[i];
485
486         if (!enter_repo(dir, strict))
487                 die("'%s': unable to chdir or not a git archive", dir);
488
489         upload_pack();
490         return 0;
491 }