Git-aware CGI to provide dumb HTTP transport
[git/git.git] / http-backend.c
CommitLineData
2f4038ab
SP
1#include "cache.h"
2#include "refs.h"
3#include "pkt-line.h"
4#include "object.h"
5#include "tag.h"
6#include "exec_cmd.h"
7
8static const char content_type[] = "Content-Type";
9static const char content_length[] = "Content-Length";
10static const char last_modified[] = "Last-Modified";
11
12static void format_write(int fd, const char *fmt, ...)
13{
14 static char buffer[1024];
15
16 va_list args;
17 unsigned n;
18
19 va_start(args, fmt);
20 n = vsnprintf(buffer, sizeof(buffer), fmt, args);
21 va_end(args);
22 if (n >= sizeof(buffer))
23 die("protocol error: impossibly long line");
24
25 safe_write(fd, buffer, n);
26}
27
28static void http_status(unsigned code, const char *msg)
29{
30 format_write(1, "Status: %u %s\r\n", code, msg);
31}
32
33static void hdr_str(const char *name, const char *value)
34{
35 format_write(1, "%s: %s\r\n", name, value);
36}
37
38static void hdr_int(const char *name, size_t value)
39{
40 format_write(1, "%s: %" PRIuMAX "\r\n", name, value);
41}
42
43static void hdr_date(const char *name, unsigned long when)
44{
45 const char *value = show_date(when, 0, DATE_RFC2822);
46 hdr_str(name, value);
47}
48
49static void hdr_nocache(void)
50{
51 hdr_str("Expires", "Fri, 01 Jan 1980 00:00:00 GMT");
52 hdr_str("Pragma", "no-cache");
53 hdr_str("Cache-Control", "no-cache, max-age=0, must-revalidate");
54}
55
56static void hdr_cache_forever(void)
57{
58 unsigned long now = time(NULL);
59 hdr_date("Date", now);
60 hdr_date("Expires", now + 31536000);
61 hdr_str("Cache-Control", "public, max-age=31536000");
62}
63
64static void end_headers(void)
65{
66 safe_write(1, "\r\n", 2);
67}
68
69static NORETURN void not_found(const char *err, ...)
70{
71 va_list params;
72
73 http_status(404, "Not Found");
74 hdr_nocache();
75 end_headers();
76
77 va_start(params, err);
78 if (err && *err)
79 vfprintf(stderr, err, params);
80 va_end(params);
81 exit(0);
82}
83
84static void send_strbuf(const char *type, struct strbuf *buf)
85{
86 hdr_int(content_length, buf->len);
87 hdr_str(content_type, type);
88 end_headers();
89 safe_write(1, buf->buf, buf->len);
90}
91
92static void send_file(const char *the_type, const char *name)
93{
94 const char *p = git_path("%s", name);
95 size_t buf_alloc = 8192;
96 char *buf = xmalloc(buf_alloc);
97 int fd;
98 struct stat sb;
99 size_t size;
100
101 fd = open(p, O_RDONLY);
102 if (fd < 0)
103 not_found("Cannot open '%s': %s", p, strerror(errno));
104 if (fstat(fd, &sb) < 0)
105 die_errno("Cannot stat '%s'", p);
106
107 size = xsize_t(sb.st_size);
108
109 hdr_int(content_length, size);
110 hdr_str(content_type, the_type);
111 hdr_date(last_modified, sb.st_mtime);
112 end_headers();
113
114 while (size) {
115 ssize_t n = xread(fd, buf, buf_alloc);
116 if (n < 0)
117 die_errno("Cannot read '%s'", p);
118 if (!n)
119 break;
120 safe_write(1, buf, n);
121 }
122 close(fd);
123 free(buf);
124}
125
126static void get_text_file(char *name)
127{
128 hdr_nocache();
129 send_file("text/plain", name);
130}
131
132static void get_loose_object(char *name)
133{
134 hdr_cache_forever();
135 send_file("application/x-git-loose-object", name);
136}
137
138static void get_pack_file(char *name)
139{
140 hdr_cache_forever();
141 send_file("application/x-git-packed-objects", name);
142}
143
144static void get_idx_file(char *name)
145{
146 hdr_cache_forever();
147 send_file("application/x-git-packed-objects-toc", name);
148}
149
150static int show_text_ref(const char *name, const unsigned char *sha1,
151 int flag, void *cb_data)
152{
153 struct strbuf *buf = cb_data;
154 struct object *o = parse_object(sha1);
155 if (!o)
156 return 0;
157
158 strbuf_addf(buf, "%s\t%s\n", sha1_to_hex(sha1), name);
159 if (o->type == OBJ_TAG) {
160 o = deref_tag(o, name, 0);
161 if (!o)
162 return 0;
163 strbuf_addf(buf, "%s\t%s^{}\n", sha1_to_hex(o->sha1), name);
164 }
165 return 0;
166}
167
168static void get_info_refs(char *arg)
169{
170 struct strbuf buf = STRBUF_INIT;
171
172 for_each_ref(show_text_ref, &buf);
173 hdr_nocache();
174 send_strbuf("text/plain", &buf);
175 strbuf_release(&buf);
176}
177
178static void get_info_packs(char *arg)
179{
180 size_t objdirlen = strlen(get_object_directory());
181 struct strbuf buf = STRBUF_INIT;
182 struct packed_git *p;
183 size_t cnt = 0;
184
185 prepare_packed_git();
186 for (p = packed_git; p; p = p->next) {
187 if (p->pack_local)
188 cnt++;
189 }
190
191 strbuf_grow(&buf, cnt * 53 + 2);
192 for (p = packed_git; p; p = p->next) {
193 if (p->pack_local)
194 strbuf_addf(&buf, "P %s\n", p->pack_name + objdirlen + 6);
195 }
196 strbuf_addch(&buf, '\n');
197
198 hdr_nocache();
199 send_strbuf("text/plain; charset=utf-8", &buf);
200 strbuf_release(&buf);
201}
202
203static NORETURN void die_webcgi(const char *err, va_list params)
204{
205 char buffer[1000];
206
207 http_status(500, "Internal Server Error");
208 hdr_nocache();
209 end_headers();
210
211 vsnprintf(buffer, sizeof(buffer), err, params);
212 fprintf(stderr, "fatal: %s\n", buffer);
213 exit(0);
214}
215
216static struct service_cmd {
217 const char *method;
218 const char *pattern;
219 void (*imp)(char *);
220} services[] = {
221 {"GET", "/HEAD$", get_text_file},
222 {"GET", "/info/refs$", get_info_refs},
223 {"GET", "/objects/info/alternates$", get_text_file},
224 {"GET", "/objects/info/http-alternates$", get_text_file},
225 {"GET", "/objects/info/packs$", get_info_packs},
226 {"GET", "/objects/[0-9a-f]{2}/[0-9a-f]{38}$", get_loose_object},
227 {"GET", "/objects/pack/pack-[0-9a-f]{40}\\.pack$", get_pack_file},
228 {"GET", "/objects/pack/pack-[0-9a-f]{40}\\.idx$", get_idx_file}
229};
230
231int main(int argc, char **argv)
232{
233 char *method = getenv("REQUEST_METHOD");
234 char *dir = getenv("PATH_TRANSLATED");
235 struct service_cmd *cmd = NULL;
236 char *cmd_arg = NULL;
237 int i;
238
239 git_extract_argv0_path(argv[0]);
240 set_die_routine(die_webcgi);
241
242 if (!method)
243 die("No REQUEST_METHOD from server");
244 if (!strcmp(method, "HEAD"))
245 method = "GET";
246 if (!dir)
247 die("No PATH_TRANSLATED from server");
248
249 for (i = 0; i < ARRAY_SIZE(services); i++) {
250 struct service_cmd *c = &services[i];
251 regex_t re;
252 regmatch_t out[1];
253
254 if (regcomp(&re, c->pattern, REG_EXTENDED))
255 die("Bogus regex in service table: %s", c->pattern);
256 if (!regexec(&re, dir, 1, out, 0)) {
257 size_t n = out[0].rm_eo - out[0].rm_so;
258
259 if (strcmp(method, c->method)) {
260 const char *proto = getenv("SERVER_PROTOCOL");
261 if (proto && !strcmp(proto, "HTTP/1.1"))
262 http_status(405, "Method Not Allowed");
263 else
264 http_status(400, "Bad Request");
265 hdr_nocache();
266 end_headers();
267 return 0;
268 }
269
270 cmd = c;
271 cmd_arg = xmalloc(n);
272 strncpy(cmd_arg, dir + out[0].rm_so + 1, n);
273 cmd_arg[n] = '\0';
274 dir[out[0].rm_so] = 0;
275 break;
276 }
277 regfree(&re);
278 }
279
280 if (!cmd)
281 not_found("Request not supported: '%s'", dir);
282
283 setup_path();
284 if (!enter_repo(dir, 0))
285 not_found("Not a git repository: '%s'", dir);
286
287 cmd->imp(cmd_arg);
288 return 0;
289}