Racy GIT (part #3)
[git] / fetch-clone.c
1 #include "cache.h"
2 #include "exec_cmd.h"
3 #include "pkt-line.h"
4 #include <sys/wait.h>
5 #include <sys/time.h>
6
7 static int finish_pack(const char *pack_tmp_name, const char *me)
8 {
9         int pipe_fd[2];
10         pid_t pid;
11         char idx[PATH_MAX];
12         char final[PATH_MAX];
13         char hash[41];
14         unsigned char sha1[20];
15         char *cp;
16         int err = 0;
17
18         if (pipe(pipe_fd) < 0)
19                 die("%s: unable to set up pipe", me);
20
21         strcpy(idx, pack_tmp_name); /* ".git/objects/pack-XXXXXX" */
22         cp = strrchr(idx, '/');
23         memcpy(cp, "/pidx", 5);
24
25         pid = fork();
26         if (pid < 0)
27                 die("%s: unable to fork off git-index-pack", me);
28         if (!pid) {
29                 close(0);
30                 dup2(pipe_fd[1], 1);
31                 close(pipe_fd[0]);
32                 close(pipe_fd[1]);
33                 execl_git_cmd("index-pack", "-o", idx, pack_tmp_name, NULL);
34                 error("cannot exec git-index-pack <%s> <%s>",
35                       idx, pack_tmp_name);
36                 exit(1);
37         }
38         close(pipe_fd[1]);
39         if (read(pipe_fd[0], hash, 40) != 40) {
40                 error("%s: unable to read from git-index-pack", me);
41                 err = 1;
42         }
43         close(pipe_fd[0]);
44
45         for (;;) {
46                 int status, code;
47                 int retval = waitpid(pid, &status, 0);
48
49                 if (retval < 0) {
50                         if (errno == EINTR)
51                                 continue;
52                         error("waitpid failed (%s)", strerror(errno));
53                         goto error_die;
54                 }
55                 if (WIFSIGNALED(status)) {
56                         int sig = WTERMSIG(status);
57                         error("git-index-pack died of signal %d", sig);
58                         goto error_die;
59                 }
60                 if (!WIFEXITED(status)) {
61                         error("git-index-pack died of unnatural causes %d",
62                               status);
63                         goto error_die;
64                 }
65                 code = WEXITSTATUS(status);
66                 if (code) {
67                         error("git-index-pack died with error code %d", code);
68                         goto error_die;
69                 }
70                 if (err)
71                         goto error_die;
72                 break;
73         }
74         hash[40] = 0;
75         if (get_sha1_hex(hash, sha1)) {
76                 error("git-index-pack reported nonsense '%s'", hash);
77                 goto error_die;
78         }
79         /* Now we have pack in pack_tmp_name[], and
80          * idx in idx[]; rename them to their final names.
81          */
82         snprintf(final, sizeof(final),
83                  "%s/pack/pack-%s.pack", get_object_directory(), hash);
84         move_temp_to_file(pack_tmp_name, final);
85         chmod(final, 0444);
86         snprintf(final, sizeof(final),
87                  "%s/pack/pack-%s.idx", get_object_directory(), hash);
88         move_temp_to_file(idx, final);
89         chmod(final, 0444);
90         return 0;
91
92  error_die:
93         unlink(idx);
94         unlink(pack_tmp_name);
95         exit(1);
96 }
97
98 static pid_t setup_sideband(int sideband, const char *me, int fd[2], int xd[2])
99 {
100         pid_t side_pid;
101
102         if (!sideband) {
103                 fd[0] = xd[0];
104                 fd[1] = xd[1];
105                 return 0;
106         }
107         /* xd[] is talking with upload-pack; subprocess reads from
108          * xd[0], spits out band#2 to stderr, and feeds us band#1
109          * through our fd[0].
110          */
111         if (pipe(fd) < 0)
112                 die("%s: unable to set up pipe", me);
113         side_pid = fork();
114         if (side_pid < 0)
115                 die("%s: unable to fork off sideband demultiplexer", me);
116         if (!side_pid) {
117                 /* subprocess */
118                 close(fd[0]);
119                 if (xd[0] != xd[1])
120                         close(xd[1]);
121                 while (1) {
122                         char buf[1024];
123                         int len = packet_read_line(xd[0], buf, sizeof(buf));
124                         if (len == 0)
125                                 break;
126                         if (len < 1)
127                                 die("%s: protocol error: no band designator",
128                                     me);
129                         len--;
130                         switch (buf[0] & 0xFF) {
131                         case 3:
132                                 safe_write(2, buf+1, len);
133                                 fprintf(stderr, "\n");
134                                 exit(1);
135                         case 2:
136                                 safe_write(2, buf+1, len);
137                                 continue;
138                         case 1:
139                                 safe_write(fd[1], buf+1, len);
140                                 continue;
141                         default:
142                                 die("%s: protocol error: bad band #%d",
143                                     me, (buf[0] & 0xFF));
144                         }
145                 }
146                 exit(0);
147         }
148         close(xd[0]);
149         close(fd[1]);
150         fd[1] = xd[1];
151         return side_pid;
152 }
153
154 int receive_unpack_pack(int xd[2], const char *me, int quiet, int sideband)
155 {
156         int status;
157         pid_t pid, side_pid;
158         int fd[2];
159
160         side_pid = setup_sideband(sideband, me, fd, xd);
161         pid = fork();
162         if (pid < 0)
163                 die("%s: unable to fork off git-unpack-objects", me);
164         if (!pid) {
165                 dup2(fd[0], 0);
166                 close(fd[0]);
167                 close(fd[1]);
168                 execl_git_cmd("unpack-objects", quiet ? "-q" : NULL, NULL);
169                 die("git-unpack-objects exec failed");
170         }
171         close(fd[0]);
172         close(fd[1]);
173         while (waitpid(pid, &status, 0) < 0) {
174                 if (errno != EINTR)
175                         die("waiting for git-unpack-objects: %s",
176                             strerror(errno));
177         }
178         if (WIFEXITED(status)) {
179                 int code = WEXITSTATUS(status);
180                 if (code)
181                         die("git-unpack-objects died with error code %d",
182                             code);
183                 return 0;
184         }
185         if (WIFSIGNALED(status)) {
186                 int sig = WTERMSIG(status);
187                 die("git-unpack-objects died of signal %d", sig);
188         }
189         die("git-unpack-objects died of unnatural causes %d", status);
190 }
191
192 /*
193  * We average out the download speed over this many "events", where
194  * an event is a minimum of about half a second. That way, we get
195  * a reasonably stable number.
196  */
197 #define NR_AVERAGE (4)
198
199 /*
200  * A "binary msec" is a power-of-two-msec, aka 1/1024th of a second.
201  * Keeing the time in that format means that "bytes / msecs" means
202  * is the same as kB/s (modulo rounding).
203  *
204  * 1000512 is a magic number (usecs in a second, rounded up by half
205  * of 1024, to make "rounding" come out right ;)
206  */
207 #define usec_to_binarymsec(x) ((int)(x) / (1000512 >> 10))
208
209 int receive_keep_pack(int xd[2], const char *me, int quiet, int sideband)
210 {
211         char tmpfile[PATH_MAX];
212         int ofd, ifd, fd[2];
213         unsigned long total;
214         static struct timeval prev_tv;
215         struct average {
216                 unsigned long bytes;
217                 unsigned long time;
218         } download[NR_AVERAGE] = { {0, 0}, };
219         unsigned long avg_bytes, avg_time;
220         int idx = 0;
221
222         setup_sideband(sideband, me, fd, xd);
223
224         ifd = fd[0];
225         snprintf(tmpfile, sizeof(tmpfile),
226                  "%s/pack/tmp-XXXXXX", get_object_directory());
227         ofd = mkstemp(tmpfile);
228         if (ofd < 0)
229                 return error("unable to create temporary file %s", tmpfile);
230
231         gettimeofday(&prev_tv, NULL);
232         total = 0;
233         avg_bytes = 0;
234         avg_time = 0;
235         while (1) {
236                 char buf[8192];
237                 ssize_t sz, wsz, pos;
238                 sz = read(ifd, buf, sizeof(buf));
239                 if (sz == 0)
240                         break;
241                 if (sz < 0) {
242                         if (errno != EINTR && errno != EAGAIN) {
243                                 error("error reading pack (%s)", strerror(errno));
244                                 close(ofd);
245                                 unlink(tmpfile);
246                                 return -1;
247                         }
248                         sz = 0;
249                 }
250                 pos = 0;
251                 while (pos < sz) {
252                         wsz = write(ofd, buf + pos, sz - pos);
253                         if (wsz < 0) {
254                                 error("error writing pack (%s)",
255                                       strerror(errno));
256                                 close(ofd);
257                                 unlink(tmpfile);
258                                 return -1;
259                         }
260                         pos += wsz;
261                 }
262                 total += sz;
263                 if (!quiet) {
264                         static unsigned long last;
265                         struct timeval tv;
266                         unsigned long diff = total - last;
267                         /* not really "msecs", but a power-of-two millisec (1/1024th of a sec) */
268                         unsigned long msecs;
269
270                         gettimeofday(&tv, NULL);
271                         msecs = tv.tv_sec - prev_tv.tv_sec;
272                         msecs <<= 10;
273                         msecs += usec_to_binarymsec(tv.tv_usec - prev_tv.tv_usec);
274
275                         if (msecs > 500) {
276                                 prev_tv = tv;
277                                 last = total;
278
279                                 /* Update averages ..*/
280                                 avg_bytes += diff;
281                                 avg_time += msecs;
282                                 avg_bytes -= download[idx].bytes;
283                                 avg_time -= download[idx].time;
284                                 download[idx].bytes = diff;
285                                 download[idx].time = msecs;
286                                 idx++;
287                                 if (idx >= NR_AVERAGE)
288                                         idx = 0;
289
290                                 fprintf(stderr, "%4lu.%03luMB  (%lu kB/s)      \r",
291                                         total >> 20,
292                                         1000*((total >> 10) & 1023)>>10,
293                                         avg_bytes / avg_time );
294                         }
295                 }
296         }
297         close(ofd);
298         return finish_pack(tmpfile, me);
299 }