Fix up "for_each_ref()" to be more usable, and use it in git-fsck-cache
[git/git.git] / receive-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 receive_pack_usage[] = "git-receive-pack <git-dir>";
7
8 static const char *unpacker = "git-unpack-objects";
9
10 static int show_ref(const char *path, const unsigned char *sha1)
11 {
12 packet_write(1, "%s %s\n", sha1_to_hex(sha1), path);
13 return 0;
14 }
15
16 static void write_head_info(void)
17 {
18 for_each_ref(show_ref);
19 }
20
21 struct command {
22 struct command *next;
23 unsigned char old_sha1[20];
24 unsigned char new_sha1[20];
25 char ref_name[0];
26 };
27
28 struct command *commands = NULL;
29
30 static int is_all_zeroes(const char *hex)
31 {
32 int i;
33 for (i = 0; i < 40; i++)
34 if (*hex++ != '0')
35 return 0;
36 return 1;
37 }
38
39 static int verify_old_ref(const char *name, char *hex_contents)
40 {
41 int fd, ret;
42 char buffer[60];
43
44 if (is_all_zeroes(hex_contents))
45 return 0;
46 fd = open(name, O_RDONLY);
47 if (fd < 0)
48 return -1;
49 ret = read(fd, buffer, 40);
50 close(fd);
51 if (ret != 40)
52 return -1;
53 if (memcmp(buffer, hex_contents, 40))
54 return -1;
55 return 0;
56 }
57
58 static void update(const char *name, unsigned char *old_sha1, unsigned char *new_sha1)
59 {
60 char new_hex[60], *old_hex, *lock_name;
61 int newfd, namelen, written;
62
63 namelen = strlen(name);
64 lock_name = xmalloc(namelen + 10);
65 memcpy(lock_name, name, namelen);
66 memcpy(lock_name + namelen, ".lock", 6);
67
68 strcpy(new_hex, sha1_to_hex(new_sha1));
69 old_hex = sha1_to_hex(old_sha1);
70 if (!has_sha1_file(new_sha1))
71 die("unpack should have generated %s, but I can't find it!", new_hex);
72
73 newfd = open(lock_name, O_CREAT | O_EXCL | O_WRONLY, 0644);
74 if (newfd < 0)
75 die("unable to create %s (%s)", lock_name, strerror(errno));
76
77 /* Write the ref with an ending '\n' */
78 new_hex[40] = '\n';
79 new_hex[41] = 0;
80 written = write(newfd, new_hex, 41);
81 /* Remove the '\n' again */
82 new_hex[40] = 0;
83
84 close(newfd);
85 if (written != 41) {
86 unlink(lock_name);
87 die("unable to write %s", lock_name);
88 }
89 if (verify_old_ref(name, old_hex) < 0) {
90 unlink(lock_name);
91 die("%s changed during push", name);
92 }
93 if (rename(lock_name, name) < 0) {
94 unlink(lock_name);
95 die("unable to replace %s", name);
96 }
97 fprintf(stderr, "%s: %s -> %s\n", name, old_hex, new_hex);
98 }
99
100
101 /*
102 * This gets called after(if) we've successfully
103 * unpacked the data payload.
104 */
105 static void execute_commands(void)
106 {
107 struct command *cmd = commands;
108
109 while (cmd) {
110 update(cmd->ref_name, cmd->old_sha1, cmd->new_sha1);
111 cmd = cmd->next;
112 }
113 }
114
115 static void read_head_info(void)
116 {
117 struct command **p = &commands;
118 for (;;) {
119 static char line[1000];
120 unsigned char old_sha1[20], new_sha1[20];
121 struct command *cmd;
122 int len;
123
124 len = packet_read_line(0, line, sizeof(line));
125 if (!len)
126 break;
127 if (line[len-1] == '\n')
128 line[--len] = 0;
129 if (len < 83 ||
130 line[40] != ' ' ||
131 line[81] != ' ' ||
132 get_sha1_hex(line, old_sha1) ||
133 get_sha1_hex(line + 41, new_sha1))
134 die("protocol error: expected old/new/ref, got '%s'", line);
135 cmd = xmalloc(sizeof(struct command) + len - 80);
136 memcpy(cmd->old_sha1, old_sha1, 20);
137 memcpy(cmd->new_sha1, new_sha1, 20);
138 memcpy(cmd->ref_name, line + 82, len - 81);
139 cmd->next = NULL;
140 *p = cmd;
141 p = &cmd->next;
142 }
143 }
144
145 static void unpack(void)
146 {
147 pid_t pid = fork();
148
149 if (pid < 0)
150 die("unpack fork failed");
151 if (!pid) {
152 execlp(unpacker, unpacker, NULL);
153 die("unpack execute failed");
154 }
155
156 for (;;) {
157 int status, code;
158 int retval = waitpid(pid, &status, 0);
159
160 if (retval < 0) {
161 if (errno == EINTR)
162 continue;
163 die("waitpid failed (%s)", strerror(retval));
164 }
165 if (retval != pid)
166 die("waitpid is confused");
167 if (WIFSIGNALED(status))
168 die("%s died of signal %d", unpacker, WTERMSIG(status));
169 if (!WIFEXITED(status))
170 die("%s died out of really strange complications", unpacker);
171 code = WEXITSTATUS(status);
172 if (code)
173 die("%s exited with error code %d", unpacker, code);
174 return;
175 }
176 }
177
178 int main(int argc, char **argv)
179 {
180 int i;
181 const char *dir = NULL;
182
183 argv++;
184 for (i = 1; i < argc; i++) {
185 const char *arg = *argv++;
186
187 if (*arg == '-') {
188 /* Do flag handling here */
189 usage(receive_pack_usage);
190 }
191 if (dir)
192 usage(receive_pack_usage);
193 dir = arg;
194 }
195 if (!dir)
196 usage(receive_pack_usage);
197
198 /* chdir to the directory. If that fails, try appending ".git" */
199 if (chdir(dir) < 0) {
200 static char path[PATH_MAX];
201 snprintf(path, sizeof(path), "%s.git", dir);
202 if (chdir(path) < 0)
203 die("unable to cd to %s", dir);
204 }
205
206 /* If we have a ".git" directory, chdir to it */
207 chdir(".git");
208 setenv("GIT_DIR", ".", 1);
209
210 if (access("objects", X_OK) < 0 || access("refs/heads", X_OK) < 0)
211 die("%s doesn't appear to be a git directory", dir);
212 write_head_info();
213
214 /* EOF */
215 packet_flush(1);
216
217 read_head_info();
218 if (commands) {
219 unpack();
220 execute_commands();
221 }
222 return 0;
223 }