summaryrefslogtreecommitdiff
path: root/clone-pack.c
blob: 8f5209cfd5bfa5e2cc97333a33432b747f90d96d (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
#include "cache.h"
#include "refs.h"
#include "pkt-line.h"
#include <sys/wait.h>
 
static int quiet;
static const char clone_pack_usage[] = "git-clone-pack [host:]directory [heads]*";
static const char *exec = "git-upload-pack";
 
struct ref {
	struct ref *next;
	unsigned char sha1[20];
	char name[0];
};
 
static struct ref *get_remote_refs(int fd, int nr_match, char **match)
{
	struct ref *ref_list = NULL, **next_ref = &ref_list;
 
	for (;;) {
		static char line[1000];
		unsigned char sha1[20];
		struct ref *ref;
		char *refname;
		int len;
 
		len = packet_read_line(fd, line, sizeof(line));
		if (!len)
			break;
		if (line[len-1] == '\n')
			line[--len] = 0;
		if (len < 42 || get_sha1_hex(line, sha1))
			die("git-fetch-pack: protocol error - expected ref descriptor, got '%sĄ'", line);
		refname = line+41;
		len = len-40;
		if (nr_match && !path_match(refname, nr_match, match))
			continue;
		ref = xmalloc(sizeof(struct ref) + len);
		ref->next = NULL;
		memcpy(ref->sha1, sha1, 20);
		memcpy(ref->name, refname, len);
		*next_ref = ref;
		next_ref = &ref->next;
	}
	return ref_list;
}
 
static void clone_handshake(int fd[2], struct ref *ref)
{
	unsigned char sha1[20];
 
	while (ref) {
		packet_write(fd[1], "want %s\n", sha1_to_hex(ref->sha1));
		ref = ref->next;
	}
	packet_flush(fd[1]);
 
	/* We don't have nuttin' */
	packet_write(fd[1], "done\n");
	if (get_ack(fd[0], sha1))
		error("Huh! git-clone-pack got positive ack for %s", sha1_to_hex(sha1));
}
 
static int is_master(struct ref *ref)
{
	return !strcmp(ref->name, "refs/heads/master");
}
 
static void write_one_ref(struct ref *ref)
{
	char *path = git_path(ref->name);
	int fd;
	char *hex;
 
	if (safe_create_leading_directories(path))
		die("unable to create leading directory for %s", ref->name);
	fd = open(path, O_CREAT | O_EXCL | O_WRONLY, 0666);
	if (fd < 0)
		die("unable to create ref %s", ref->name);
	hex = sha1_to_hex(ref->sha1);
	hex[40] = '\n';
	if (write(fd, hex, 41) != 41)
		die("unable to write ref %s", ref->name);
	close(fd);
}
 
static void write_refs(struct ref *ref)
{
	struct ref *head = NULL, *head_ptr, *master_ref;
	char *head_path;
 
	if (!strcmp(ref->name, "HEAD")) {
		head = ref;
		ref = ref->next;
	}
	head_ptr = NULL;
	master_ref = NULL;
	while (ref) {
		if (is_master(ref))
			master_ref = ref;
		if (head && !memcmp(ref->sha1, head->sha1, 20)) {
			if (!head_ptr || ref == master_ref)
				head_ptr = ref;
		}
		write_one_ref(ref);
		ref = ref->next;
	}
	if (!head)
		return;
 
	head_path = git_path("HEAD");
	if (!head_ptr) {
		/*
		 * If we had a master ref, and it wasn't HEAD, we need to undo the
		 * symlink, and write a standalone HEAD. Give a warning, because that's
		 * really really wrong.
		 */
		if (master_ref) {
			error("HEAD doesn't point to any refs! Making standalone HEAD");
			unlink(head_path);
		}
		write_one_ref(head);
		return;
	}
 
	/* We reset to the master branch if it's available */
	if (master_ref)
		return;
 
	/*
	 * Uhhuh. Other end didn't have master. We start HEAD off with
	 * the first branch with the same value.
	 */
	unlink(head_path);
	if (symlink(head_ptr->name, head_path) < 0)
		die("unable to link HEAD to %s", head_ptr->name);
}
 
static int clone_pack(int fd[2], int nr_match, char **match)
{
	struct ref *refs;
	int status;
	pid_t pid;
 
	refs = get_remote_refs(fd[0], nr_match, match);
	if (!refs) {
		packet_flush(fd[1]);
		die("no matching remote head");
	}
	clone_handshake(fd, refs);
	pid = fork();
	if (pid < 0)
		die("git-clone-pack: unable to fork off git-unpack-objects");
	if (!pid) {
		close(fd[1]);
		dup2(fd[0], 0);
		close(fd[0]);
		execlp("git-unpack-objects", "git-unpack-objects",
			quiet ? "-q" : NULL, NULL);
		die("git-unpack-objects exec failed");
	}
	close(fd[0]);
	close(fd[1]);
	while (waitpid(pid, &status, 0) < 0) {
		if (errno != EINTR)
			die("waiting for git-unpack-objects: %s", strerror(errno));
	}
	if (WIFEXITED(status)) {
		int code = WEXITSTATUS(status);
		if (code)
			die("git-unpack-objects died with error code %d", code);
		write_refs(refs);
		return 0;
	}
	if (WIFSIGNALED(status)) {
		int sig = WTERMSIG(status);
		die("git-unpack-objects died of signal %d", sig);
	}
	die("Sherlock Holmes! git-unpack-objects died of unnatural causes %d!", status);
}
 
int main(int argc, char **argv)
{
	int i, ret, nr_heads;
	char *dest = NULL, **heads;
	int fd[2];
	pid_t pid;
 
	nr_heads = 0;
	heads = NULL;
	for (i = 1; i < argc; i++) {
		char *arg = argv[i];
 
		if (*arg == '-') {
			if (!strcmp("-q", arg)) {
				quiet = 1;
				continue;
			}
			usage(clone_pack_usage);
		}
		dest = arg;
		heads = argv + i + 1;
		nr_heads = argc - i - 1;
		break;
	}
	if (!dest)
		usage(clone_pack_usage);
	pid = git_connect(fd, dest, exec);
	if (pid < 0)
		return 1;
	ret = clone_pack(fd, nr_heads, heads);
	close(fd[0]);
	close(fd[1]);
	finish_connect(pid);
	return ret;
}