examples: Added some commentary.
[ashd.git] / src / callcgi.c
CommitLineData
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1/*
2 ashd - A Sane HTTP Daemon
3 Copyright (C) 2008 Fredrik Tolf <fredrik@dolda2000.com>
4
5 This program is free software: you can redistribute it and/or modify
6 it under the terms of the GNU General Public License as published by
7 the Free Software Foundation, either version 3 of the License, or
8 (at your option) any later version.
9
10 This program is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 GNU General Public License for more details.
14
15 You should have received a copy of the GNU General Public License
16 along with this program. If not, see <http://www.gnu.org/licenses/>.
17*/
18
19#include <stdlib.h>
20#include <string.h>
21#include <stdio.h>
22#include <unistd.h>
23#include <errno.h>
24#include <ctype.h>
25#include <signal.h>
df96b222 26#include <sys/poll.h>
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27
28#ifdef HAVE_CONFIG_H
29#include <config.h>
30#endif
31#include <utils.h>
32#include <log.h>
09c82f9c 33#include <req.h>
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34
35static char **environ;
36
df96b222 37static int passdata(FILE *in, FILE *out)
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38{
39 int ret;
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40 char buf[65536];
41 struct pollfd pfds[2];
8cc51634 42
8cc51634 43 while(!feof(in)) {
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44 memset(pfds, 0, sizeof(struct pollfd) * 2);
45 pfds[0].fd = fileno(in);
46 pfds[0].events = POLLIN;
47 pfds[1].fd = fileno(out);
48 pfds[1].events = POLLHUP;
49 ret = poll(pfds, 2, -1);
50 if(ret < 0) {
51 if(errno != EINTR) {
52 flog(LOG_ERR, "callcgi: error in poll: %s", strerror(errno));
53 return(1);
54 }
8cc51634 55 }
df96b222 56 if(ret > 0) {
19409e87 57 if(pfds[0].revents & (POLLIN | POLLERR | POLLHUP)) {
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58 ret = fread(buf, 1, 65536, in);
59 if(ferror(in)) {
60 flog(LOG_ERR, "callcgi: could not read input: %s", strerror(errno));
61 return(1);
62 }
63 if(fwrite(buf, 1, ret, out) != ret) {
64 flog(LOG_ERR, "callcgi: could not write output: %s", strerror(errno));
65 return(1);
66 }
67 }
68 if(pfds[1].revents & POLLHUP)
69 return(1);
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70 }
71 }
df96b222 72 return(0);
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73}
74
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75static char *absolutify(char *file)
76{
77 char cwd[1024];
78
79 if(*file != '/') {
80 getcwd(cwd, sizeof(cwd));
81 return(sprintf2("%s/%s", cwd, file));
82 }
83 return(sstrdup(file));
84}
85
df96b222 86static pid_t forkchild(int inpath, char *prog, char *file, char *method, char *url, char *rest, int *infd, int *outfd)
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87{
88 int i;
85059e82 89 char *qp, **env, *name;
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90 int inp[2], outp[2];
91 pid_t pid;
09c82f9c 92 char *unqr;
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93
94 pipe(inp);
95 pipe(outp);
96 if((pid = fork()) < 0) {
97 flog(LOG_ERR, "callcgi: could not fork");
98 exit(1);
99 }
100 if(pid == 0) {
101 close(inp[1]);
102 close(outp[0]);
103 dup2(inp[0], 0);
104 dup2(outp[1], 1);
105 for(i = 3; i < FD_SETSIZE; i++)
106 close(i);
107 if((qp = strchr(url, '?')) != NULL)
108 *(qp++) = 0;
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109 putenv(sprintf2("SERVER_SOFTWARE=ashd/%s", VERSION));
110 putenv("GATEWAY_INTERFACE=CGI/1.1");
111 if(getenv("HTTP_VERSION"))
147c2b51 112 putenv(sprintf2("SERVER_PROTOCOL=%s", getenv("HTTP_VERSION")));
8cc51634 113 putenv(sprintf2("REQUEST_METHOD=%s", method));
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114 unqr = unquoteurl(rest);
115 putenv(sprintf2("PATH_INFO=%s", unqr?unqr:rest));
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116 name = url;
117 /* XXX: This is an ugly hack (I think), but though I can think
118 * of several alternatives, none seem to be better. */
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119 if(*rest && (strlen(url) >= strlen(rest)) &&
120 !strcmp(rest, url + strlen(url) - strlen(rest))) {
121 name = sprintf2("%.*s", (int)(strlen(url) - strlen(rest)), url);
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122 }
123 putenv(sprintf2("SCRIPT_NAME=%s", name));
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124 putenv(sprintf2("QUERY_STRING=%s", qp?qp:""));
125 if(getenv("REQ_HOST"))
126 putenv(sprintf2("SERVER_NAME=%s", getenv("REQ_HOST")));
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127 if(getenv("REQ_X_ASH_SERVER_PORT"))
128 putenv(sprintf2("SERVER_PORT=%s", getenv("REQ_X_ASH_SERVER_PORT")));
129 if(getenv("REQ_X_ASH_PROTOCOL") && !strcmp(getenv("REQ_X_ASH_PROTOCOL"), "https"))
f0a758cc 130 putenv("HTTPS=on");
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131 if(getenv("REQ_X_ASH_ADDRESS"))
132 putenv(sprintf2("REMOTE_ADDR=%s", getenv("REQ_X_ASH_ADDRESS")));
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133 if(getenv("REQ_X_ASH_REMOTE_USER"))
134 putenv(sprintf2("REMOTE_USER=%s", getenv("REQ_X_ASH_REMOTE_USER")));
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135 if(getenv("REQ_CONTENT_TYPE"))
136 putenv(sprintf2("CONTENT_TYPE=%s", getenv("REQ_CONTENT_TYPE")));
137 if(getenv("REQ_CONTENT_LENGTH"))
138 putenv(sprintf2("CONTENT_LENGTH=%s", getenv("REQ_CONTENT_LENGTH")));
139 for(env = environ; *env; env++) {
140 if(!strncmp(*env, "REQ_", 4))
141 putenv(sprintf2("HTTP_%s", (*env) + 4));
142 }
143 /*
144 * This is (understandably) missing from the CGI
145 * specification, but PHP seems to require it.
146 */
bac8c1f9 147 putenv(sprintf2("SCRIPT_FILENAME=%s", absolutify(file)));
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148 if(inpath)
149 execlp(prog, prog, file, NULL);
150 else
151 execl(prog, prog, file, NULL);
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152 exit(127);
153 }
154 close(inp[0]);
155 close(outp[1]);
156 *infd = inp[1];
157 *outfd = outp[0];
df96b222 158 return(pid);
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159}
160
161static void trim(struct charbuf *buf)
162{
163 char *p;
164
165 for(p = buf->b; (p - buf->b < buf->d) && isspace(*p); p++);
166 memmove(buf->b, p, buf->d -= (p - buf->b));
167 for(p = buf->b + buf->d - 1; (p > buf->b) && isspace(*p); p--, buf->d--);
168}
169
09c82f9c 170static char **parsecgiheaders(FILE *s)
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171{
172 int c, state;
173 struct charvbuf hbuf;
174 struct charbuf buf;
175
176 bufinit(hbuf);
177 bufinit(buf);
178 state = 0;
179 while(1) {
180 c = fgetc(s);
181 again:
182 if(state == 0) {
183 if(c == '\r') {
184 } else if(c == '\n') {
185 break;
186 } else if(c == EOF) {
187 goto fail;
188 } else {
189 state = 1;
190 goto again;
191 }
192 } else if(state == 1) {
193 if(c == ':') {
194 trim(&buf);
195 bufadd(buf, 0);
196 bufadd(hbuf, buf.b);
197 bufinit(buf);
198 state = 2;
199 } else if(c == '\r') {
200 } else if(c == '\n') {
201 goto fail;
202 } else if(c == EOF) {
203 goto fail;
204 } else {
205 bufadd(buf, c);
206 }
207 } else if(state == 2) {
208 if(c == '\r') {
209 } else if(c == '\n') {
210 trim(&buf);
211 bufadd(buf, 0);
212 bufadd(hbuf, buf.b);
213 bufinit(buf);
214 state = 0;
215 } else if(c == EOF) {
216 goto fail;
217 } else {
218 bufadd(buf, c);
219 }
220 }
221 }
222 bufadd(hbuf, NULL);
223 return(hbuf.b);
224
225fail:
226 buffree(hbuf);
227 buffree(buf);
228 return(NULL);
229}
230
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231static char *defstatus(int code)
232{
233 if(code == 200)
234 return("OK");
235 else if(code == 201)
236 return("Created");
237 else if(code == 202)
238 return("Accepted");
239 else if(code == 204)
240 return("No Content");
241 else if(code == 300)
242 return("Multiple Choices");
243 else if(code == 301)
244 return("Moved Permanently");
245 else if(code == 302)
246 return("Found");
247 else if(code == 303)
248 return("See Other");
249 else if(code == 304)
250 return("Not Modified");
251 else if(code == 307)
252 return("Moved Temporarily");
253 else if(code == 400)
254 return("Bad Request");
255 else if(code == 401)
256 return("Unauthorized");
257 else if(code == 403)
258 return("Forbidden");
259 else if(code == 404)
260 return("Not Found");
261 else if(code == 500)
262 return("Internal Server Error");
263 else if(code == 501)
264 return("Not Implemented");
265 else if(code == 503)
266 return("Service Unavailable");
267 else
268 return("Unknown status");
269}
270
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271static void sendstatus(char **headers, FILE *out)
272{
273 char **hp;
274 char *status, *location;
275
276 hp = headers;
277 status = location = NULL;
278 while(*hp) {
279 if(!strcasecmp(hp[0], "status")) {
280 status = hp[1];
281 /* Clear this header, so that it is not transmitted by sendheaders. */
282 **hp = 0;
283 } else if(!strcasecmp(hp[0], "location")) {
284 location = hp[1];
f9255ddd 285 hp += 2;
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286 } else {
287 hp += 2;
288 }
289 }
290 if(status) {
2e535ab0 291 if(strchr(status, ' '))
81cfca6c 292 fprintf(out, "HTTP/1.1 %s\n", status);
2e535ab0 293 else
81cfca6c 294 fprintf(out, "HTTP/1.1 %i %s\n", atoi(status), defstatus(atoi(status)));
8cc51634 295 } else if(location) {
81cfca6c 296 fprintf(out, "HTTP/1.1 303 See Other\n");
8cc51634 297 } else {
81cfca6c 298 fprintf(out, "HTTP/1.1 200 OK\n");
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299 }
300}
301
302static void sendheaders(char **headers, FILE *out)
303{
304 while(*headers) {
305 if(**headers)
81cfca6c 306 fprintf(out, "%s: %s\n", headers[0], headers[1]);
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307 headers += 2;
308 }
309}
310
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311static void usage(void)
312{
5e74f3f1 313 flog(LOG_ERR, "usage: callcgi [-c] [-p PROGRAM] METHOD URL REST");
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314}
315
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316int main(int argc, char **argv, char **envp)
317{
341b3f0b 318 int c;
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319 char *file, *prog, *sp;
320 int inpath, cd;
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321 int infd, outfd;
322 FILE *in, *out;
8cc51634 323 char **headers;
df96b222 324 pid_t child;
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325
326 environ = envp;
327 signal(SIGPIPE, SIG_IGN);
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328
329 prog = NULL;
330 inpath = 0;
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331 cd = 0;
332 while((c = getopt(argc, argv, "cp:")) >= 0) {
341b3f0b 333 switch(c) {
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334 case 'c':
335 cd = 1;
336 break;
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337 case 'p':
338 prog = optarg;
339 inpath = 1;
340 break;
341 default:
342 usage();
343 exit(1);
344 }
345 }
346
347 if(argc - optind < 3) {
348 usage();
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349 exit(1);
350 }
351 if((file = getenv("REQ_X_ASH_FILE")) == NULL) {
352 flog(LOG_ERR, "callcgi: needs to be called with the X-Ash-File header");
353 exit(1);
354 }
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355
356 if(cd) {
357 /* This behavior is encouraged by the CGI specification (RFC 3875, 7.2),
358 * but not strictly required, and I get the feeling it might break some
359 * relative paths here or there, so it's not the default for now. */
360 if((sp = strrchr(file, '/')) != NULL) {
361 *sp = 0;
362 if(chdir(file)) {
363 *sp = '/';
364 } else {
365 file = sp + 1;
366 }
367 }
368 }
369
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370 if(prog == NULL)
371 prog = file;
df96b222 372 child = forkchild(inpath, prog, file, argv[optind], argv[optind + 1], argv[optind + 2], &infd, &outfd);
341b3f0b 373 in = fdopen(infd, "w");
df96b222 374 passdata(stdin, in); /* Ignore errors, perhaps? */
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375 fclose(in);
376 out = fdopen(outfd, "r");
09c82f9c 377 if((headers = parsecgiheaders(out)) == NULL) {
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378 flog(LOG_WARNING, "CGI handler returned invalid headers");
379 exit(1);
380 }
381 sendstatus(headers, stdout);
382 sendheaders(headers, stdout);
81cfca6c 383 printf("\n");
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384 if(passdata(out, stdout))
385 kill(child, SIGINT);
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386 return(0);
387}