b8367a4d625fdfe59cf30e0a4aed40443139c40c
[git/git.git] / fetch-pack.c
1 #include "cache.h"
2 #include "refs.h"
3 #include "pkt-line.h"
4 #include <sys/wait.h>
5
6 static const char fetch_pack_usage[] = "git-fetch-pack [host:]directory [heads]* < mycommitlist";
7 static const char *exec = "git-upload-pack";
8
9 static int get_ack(int fd, unsigned char *result_sha1)
10 {
11 static char line[1000];
12 int len = packet_read_line(fd, line, sizeof(line));
13
14 if (!len)
15 die("git-fetch-pack: expected ACK/NAK, got EOF");
16 if (line[len-1] == '\n')
17 line[--len] = 0;
18 if (!strcmp(line, "NAK"))
19 return 0;
20 if (!strncmp(line, "ACK ", 3)) {
21 if (!get_sha1_hex(line+4, result_sha1))
22 return 1;
23 }
24 die("git-fetch_pack: expected ACK/NAK, got '%s'", line);
25 }
26
27 static int find_common(int fd[2], unsigned char *result_sha1, unsigned char *remote)
28 {
29 static char line[1000];
30 int count = 0, flushes = 0, retval;
31 FILE *revs;
32
33 revs = popen("git-rev-list $(git-rev-parse --all)", "r");
34 if (!revs)
35 die("unable to run 'git-rev-list'");
36 packet_write(fd[1], "want %s\n", sha1_to_hex(remote));
37 packet_flush(fd[1]);
38 flushes = 1;
39 retval = -1;
40 while (fgets(line, sizeof(line), revs) != NULL) {
41 unsigned char sha1[20];
42 if (get_sha1_hex(line, sha1))
43 die("git-fetch-pack: expected object name, got crud");
44 packet_write(fd[1], "have %s\n", sha1_to_hex(sha1));
45 if (!(31 & ++count)) {
46 packet_flush(fd[1]);
47 flushes++;
48
49 /*
50 * We keep one window "ahead" of the other side, and
51 * will wait for an ACK only on the next one
52 */
53 if (count == 32)
54 continue;
55 if (get_ack(fd[0], result_sha1)) {
56 flushes = 0;
57 retval = 0;
58 break;
59 }
60 flushes--;
61 }
62 }
63 pclose(revs);
64 packet_write(fd[1], "done\n");
65 while (flushes) {
66 flushes--;
67 if (get_ack(fd[0], result_sha1))
68 return 0;
69 }
70 return retval;
71 }
72
73 static int get_old_sha1(const char *refname, unsigned char *sha1)
74 {
75 static char pathname[PATH_MAX];
76 const char *git_dir;
77 int fd, ret;
78
79 git_dir = gitenv(GIT_DIR_ENVIRONMENT) ? : DEFAULT_GIT_DIR_ENVIRONMENT;
80 snprintf(pathname, sizeof(pathname), "%s/%s", git_dir, refname);
81 fd = open(pathname, O_RDONLY);
82 ret = -1;
83 if (fd >= 0) {
84 char buffer[60];
85 if (read(fd, buffer, sizeof(buffer)) >= 40)
86 ret = get_sha1_hex(buffer, sha1);
87 close(fd);
88 }
89 return ret;
90 }
91
92 static int check_ref(const char *refname, const unsigned char *sha1)
93 {
94 unsigned char mysha1[20];
95 char oldhex[41];
96
97 if (get_old_sha1(refname, mysha1) < 0)
98 memset(mysha1, 0, 20);
99
100 if (!memcmp(sha1, mysha1, 20)) {
101 fprintf(stderr, "%s: unchanged\n", refname);
102 return 0;
103 }
104
105 memcpy(oldhex, sha1_to_hex(mysha1), 41);
106 fprintf(stderr, "%s: %s (%s)\n", refname, sha1_to_hex(sha1), oldhex);
107 return 1;
108 }
109
110 static int get_remote_heads(int fd, int nr_match, char **match, unsigned char *result)
111 {
112 int count = 0;
113
114 for (;;) {
115 static char line[1000];
116 unsigned char sha1[20];
117 char *refname;
118 int len;
119
120 len = packet_read_line(fd, line, sizeof(line));
121 if (!len)
122 break;
123 if (line[len-1] == '\n')
124 line[--len] = 0;
125 if (len < 42 || get_sha1_hex(line, sha1))
126 die("git-fetch-pack: protocol error - expected ref descriptor, got '%sä'", line);
127 refname = line+41;
128 if (nr_match && !path_match(refname, nr_match, match))
129 continue;
130 if (check_ref(refname, sha1)) {
131 count++;
132 memcpy(result, sha1, 20);
133 }
134 }
135 return count;
136 }
137
138 static int fetch_pack(int fd[2], int nr_match, char **match)
139 {
140 unsigned char sha1[20], remote[20];
141 int heads, status;
142 pid_t pid;
143
144 heads = get_remote_heads(fd[0], nr_match, match, remote);
145 if (heads != 1) {
146 packet_flush(fd[1]);
147 die(heads ? "multiple remote heads" : "no matching remote head");
148 }
149 if (find_common(fd, sha1, remote) < 0)
150 die("git-fetch-pack: no common commits");
151 pid = fork();
152 if (pid < 0)
153 die("git-fetch-pack: unable to fork off git-unpack-objects");
154 if (!pid) {
155 close(fd[1]);
156 dup2(fd[0], 0);
157 close(fd[0]);
158 execlp("git-unpack-objects", "git-unpack-objects", NULL);
159 die("git-unpack-objects exec failed");
160 }
161 close(fd[0]);
162 close(fd[1]);
163 while (waitpid(pid, &status, 0) < 0) {
164 if (errno != EINTR)
165 die("waiting for git-unpack-objects: %s", strerror(errno));
166 }
167 if (WIFEXITED(status)) {
168 int code = WEXITSTATUS(status);
169 if (code)
170 die("git-unpack-objects died with error code %d", code);
171 puts(sha1_to_hex(remote));
172 return 0;
173 }
174 if (WIFSIGNALED(status)) {
175 int sig = WTERMSIG(status);
176 die("git-unpack-objects died of signal %d", sig);
177 }
178 die("Sherlock Holmes! git-unpack-objects died of unnatural causes %d!", status);
179 }
180
181 int main(int argc, char **argv)
182 {
183 int i, ret, nr_heads;
184 char *dest = NULL, **heads;
185 int fd[2];
186 pid_t pid;
187
188 nr_heads = 0;
189 heads = NULL;
190 for (i = 1; i < argc; i++) {
191 char *arg = argv[i];
192
193 if (*arg == '-') {
194 /* Arguments go here */
195 usage(fetch_pack_usage);
196 }
197 dest = arg;
198 heads = argv + i + 1;
199 nr_heads = argc - i - 1;
200 break;
201 }
202 if (!dest)
203 usage(fetch_pack_usage);
204 pid = git_connect(fd, dest, exec);
205 if (pid < 0)
206 return 1;
207 ret = fetch_pack(fd, nr_heads, heads);
208 close(fd[0]);
209 close(fd[1]);
210 finish_connect(pid);
211 return ret;
212 }