summaryrefslogtreecommitdiff
path: root/builtin/remote-ext.c
blob: 692c834d9dd48615e42b67e3924c64e3397ad903 (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
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
#include "builtin.h"
#include "transport.h"
#include "run-command.h"

/*
 * URL syntax:
 *	'command [arg1 [arg2 [...]]]'	Invoke command with given arguments.
 *	Special characters:
 *	'% ': Literal space in argument.
 *	'%%': Literal percent sign.
 *	'%S': Name of service (git-upload-pack/git-upload-archive/
 *		git-receive-pack.
 *	'%s': Same as \s, but with possible git- prefix stripped.
 *	'%G': Only allowed as first 'character' of argument. Do not pass this
 *		Argument to command, instead send this as name of repository
 *		in in-line git://-style request (also activates sending this
 *		style of request).
 *	'%V': Only allowed as first 'character' of argument. Used in
 *		conjunction with '%G': Do not pass this argument to command,
 *		instead send this as vhost in git://-style request (note: does
 *		not activate sending git:// style request).
 */

static char *git_req;
static char *git_req_vhost;

static char *strip_escapes(const char *str, const char *service,
	const char **next)
{
	size_t rpos = 0;
	int escape = 0;
	char special = 0;
	size_t psoff = 0;
	struct strbuf ret = STRBUF_INIT;

	/* Calculate prefix length for \s and lengths for \s and \S */
	if (!strncmp(service, "git-", 4))
		psoff = 4;

	/* Pass the service to command. */
	setenv("GIT_EXT_SERVICE", service, 1);
	setenv("GIT_EXT_SERVICE_NOPREFIX", service + psoff, 1);

	/* Scan the length of argument. */
	while (str[rpos] && (escape || str[rpos] != ' ')) {
		if (escape) {
			switch (str[rpos]) {
			case ' ':
			case '%':
			case 's':
			case 'S':
				break;
			case 'G':
			case 'V':
				special = str[rpos];
				if (rpos == 1)
					break;
				/* Fall-through to error. */
			default:
				die("Bad remote-ext placeholder '%%%c'.",
					str[rpos]);
			}
			escape = 0;
		} else
			escape = (str[rpos] == '%');
		rpos++;
	}
	if (escape && !str[rpos])
		die("remote-ext command has incomplete placeholder");
	*next = str + rpos;
	if (**next == ' ')
		++*next;	/* Skip over space */

	/*
	 * Do the actual placeholder substitution. The string will be short
	 * enough not to overflow integers.
	 */
	rpos = special ? 2 : 0;		/* Skip first 2 bytes in specials. */
	escape = 0;
	while (str[rpos] && (escape || str[rpos] != ' ')) {
		if (escape) {
			switch (str[rpos]) {
			case ' ':
			case '%':
				strbuf_addch(&ret, str[rpos]);
				break;
			case 's':
				strbuf_addstr(&ret, service + psoff);
				break;
			case 'S':
				strbuf_addstr(&ret, service);
				break;
			}
			escape = 0;
		} else
			switch (str[rpos]) {
			case '%':
				escape = 1;
				break;
			default:
				strbuf_addch(&ret, str[rpos]);
				break;
			}
		rpos++;
	}
	switch (special) {
	case 'G':
		git_req = strbuf_detach(&ret, NULL);
		return NULL;
	case 'V':
		git_req_vhost = strbuf_detach(&ret, NULL);
		return NULL;
	default:
		return strbuf_detach(&ret, NULL);
	}
}

/* Should be enough... */
#define MAXARGUMENTS 256

static const char **parse_argv(const char *arg, const char *service)
{
	int arguments = 0;
	int i;
	const char **ret;
	char *temparray[MAXARGUMENTS + 1];

	while (*arg) {
		char *expanded;
		if (arguments == MAXARGUMENTS)
			die("remote-ext command has too many arguments");
		expanded = strip_escapes(arg, service, &arg);
		if (expanded)
			temparray[arguments++] = expanded;
	}

	ret = xmalloc((arguments + 1) * sizeof(char *));
	for (i = 0; i < arguments; i++)
		ret[i] = temparray[i];
	ret[arguments] = NULL;
	return ret;
}

static void send_git_request(int stdin_fd, const char *serv, const char *repo,
	const char *vhost)
{
	size_t bufferspace;
	size_t wpos = 0;
	char *buffer;

	/*
	 * Request needs 12 bytes extra if there is vhost (xxxx \0host=\0) and
	 * 6 bytes extra (xxxx \0) if there is no vhost.
	 */
	if (vhost)
		bufferspace = strlen(serv) + strlen(repo) + strlen(vhost) + 12;
	else
		bufferspace = strlen(serv) + strlen(repo) + 6;

	if (bufferspace > 0xFFFF)
		die("Request too large to send");
	buffer = xmalloc(bufferspace);

	/* Make the packet. */
	wpos = sprintf(buffer, "%04x%s %s%c", (unsigned)bufferspace,
		serv, repo, 0);

	/* Add vhost if any. */
	if (vhost)
		sprintf(buffer + wpos, "host=%s%c", vhost, 0);

	/* Send the request */
	if (write_in_full(stdin_fd, buffer, bufferspace) < 0)
		die_errno("Failed to send request");

	free(buffer);
}

static int run_child(const char *arg, const char *service)
{
	int r;
	struct child_process child;

	memset(&child, 0, sizeof(child));
	child.in = -1;
	child.out = -1;
	child.err = 0;
	child.argv = parse_argv(arg, service);

	if (start_command(&child) < 0)
		die("Can't run specified command");

	if (git_req)
		send_git_request(child.in, service, git_req, git_req_vhost);

	r = bidirectional_transfer_loop(child.out, child.in);
	if (!r)
		r = finish_command(&child);
	else
		finish_command(&child);
	return r;
}

#define MAXCOMMAND 4096

static int command_loop(const char *child)
{
	char buffer[MAXCOMMAND];

	while (1) {
		size_t i;
		if (!fgets(buffer, MAXCOMMAND - 1, stdin)) {
			if (ferror(stdin))
				die("Comammand input error");
			exit(0);
		}
		/* Strip end of line characters. */
		i = strlen(buffer);
		while (i > 0 && isspace(buffer[i - 1]))
			buffer[--i] = 0;

		if (!strcmp(buffer, "capabilities")) {
			printf("*connect\n\n");
			fflush(stdout);
		} else if (!strncmp(buffer, "connect ", 8)) {
			printf("\n");
			fflush(stdout);
			return run_child(child, buffer + 8);
		} else {
			fprintf(stderr, "Bad command");
			return 1;
		}
	}
}

int cmd_remote_ext(int argc, const char **argv, const char *prefix)
{
	if (argc != 3)
		die("Expected two arguments");

	return command_loop(argv[2]);
}