2 * "Interpreter" that you can put in #! like this
3 * #!/usr/bin/cgi-fcgi-interp [<options>] <interpreter>
4 * #!/usr/bin/cgi-fcgi-interp [<options>],<interpreter>
6 * The result is a program which looks, when executed via the #!
7 * line, like a CGI program. But the script inside will be executed
8 * via <interpreter> in an fcgi context.
13 * The real interpreter to use. Eg "perl". Need not
14 * be an absolute path; will be fed to execvp.
17 * Use <ident> rather than hex(sha256(<script>))
18 * as the basename of the leafname of the fcgi rendezvous
19 * socket. If <ident> contains only hex digit characters it
20 * ought to be no more than 32 characters. <ident> should
21 * not contain spaces or commas (see below).
24 * Start <numservers> instances of the program. This
25 * determines the maximum concurrency. (Note that unlike
26 * speedy, the specified number of servers is started
27 * right away.) The default is 4.
30 * Debug mode. Do not actually run program. Instead, print
31 * out what we would do.
33 * <options> and <interpreter> can be put into a single argument
34 * to cgi-fcgi-interp, separated by spaces or commas. <interpreter>
37 * cgi-fcgi-interp automatically expires old sockets, including
38 * ones where the named script is out of date.
42 * Uses one of two directories
43 * /var/run/user/<UID>/cgi-fcgi-interp/
44 * ~/.cgi-fcgi-interp/<node>/
45 * and inside there uses these paths
49 * If -M<ident> is not specified then an initial substricg of the
50 * lowercase hex of the sha256 of the <script> (ie, our argv[1]) is
51 * used. The substring is chosen so that the whole path is 10 bytes
52 * shorter than sizeof(sun_path). But always at least 33 characters.
54 * <node> is truncated at the first `.' and after the first 32
58 * - see if /var/run/user exists
59 * if so, lstat /var/run/user/<UID> and check that
60 * we own it and it's X700; if not, fail
61 * if it's ok then <base> is /var/run/user/<UID>
62 * otherwise, look for and maybe create ~/.cgi-fcgi-interp
63 * (where ~ is HOME or from getpwuid)
64 * and then <base> is ~/.cgi-fcgi-interp/<node>
65 * - calculate pathname (checking <ident> length is OK)
66 * - check for and maybe create <base>
67 * - stat and lstat the <script>
68 * - stat the socket and check its timestamp
69 * if it is too hold, rename it to g<inum> (where
70 * <inum> is in decimal)
71 * and run garbage collection
72 * - run cgi-fcgi -connect SOCKET SCRIPT
85 #include <sys/types.h>
87 #include <sys/utsname.h>
88 #include <sys/socket.h>
94 #include <nettle/sha.h>
98 #define die common_die
99 #define diee common_diee
101 #define MINHEXHASH 33
103 static const char *interp, *ident;
104 static int numservers, debugmode;
106 void diee(const char *m) {
107 err(127, "error: %s failed", m);
110 static void fusagemessage(FILE *f) {
111 fprintf(f, "usage: #!/usr/bin/cgi-fcgi-interp [<options>]\n");
114 void usagemessage(void) { fusagemessage(stderr); }
116 static void of_help(const struct cmdinfo *ci, const char *val) {
117 fusagemessage(stdout);
118 if (ferror(stdout)) diee("write usage message to stdout");
122 static void of_iassign(const struct cmdinfo *ci, const char *val) {
125 errno= 0; v= strtol(val,&ep,10);
126 if (!*val || *ep || errno || v<INT_MIN || v>INT_MAX)
127 badusage("bad integer argument `%s' for --%s",val,ci->olong);
133 static const struct cmdinfo cmdinfos[]= {
134 { "help", 0, .call= of_help },
135 { 0, 'g', 1, .sassignto= &ident },
136 { 0, 'M', 1, .call=of_iassign, .iassignto= &numservers },
137 { 0, 'D', 0, .iassignto= &debugmode, .arg= 1 },
142 static const char *run_base, *command, *socket_path;
144 static bool find_run_base_var_run(void) {
149 try = m_asprintf("%s/%lu", "/var/run/user", us);
150 r = lstat(try, &stab);
152 if (errno == ENOENT ||
156 return 0; /* oh well */
157 diee("stat /var/run/user/UID");
159 if (!S_ISDIR(stab.st_mode)) {
160 warnx("%s not a directory, falling back to ~\n", try);
163 if (stab.st_uid != us) {
164 warnx("%s not owned by uid %lu, falling back to ~\n", try,
168 if (stab.st_mode & 0077) {
169 warnx("%s writeable by group or other, falling back to ~\n", try);
172 run_base = m_asprintf("%s/%s", try, "cgi-fcgi-interp");
176 static bool find_run_base_home(void) {
182 pw = getpwuid(us); if (!pw) diee("getpwent(uid)");
184 r = uname(&ut); if (r) diee("uname(2)");
185 dot = strchr(ut.nodename, '.');
187 if (sizeof(ut.nodename) > 32)
190 try = m_asprintf("%s/%s/%s", pw->pw_dir, ".cgi-fcgi-interp", ut.nodename);
195 static void find_socket_path(void) {
196 struct sockaddr_un sun;
199 us = getuid(); if (us==(uid_t)-1) diee("getuid");
201 find_run_base_var_run() ||
202 find_run_base_home() ||
205 int maxidentlen = sizeof(sun.sun_path) - strlen(run_base) - 10 - 2;
208 if (maxidentlen < MINHEXHASH)
209 errx(127,"base directory `%s'"
210 " leaves only %d characters for command name hash"
211 " which is too little (<%d)",
212 run_base, maxidentlen, MINHEXHASH);
214 int identlen = maxidentlen > 64 ? 64 : maxidentlen;
215 char *hexident = xmalloc(identlen + 2);
216 struct sha256_ctx sc;
217 unsigned char bbuf[32];
221 sha256_update(&sc,strlen(interp)+1,interp);
222 sha256_update(&sc,strlen(command)+1,command);
223 sha256_digest(&sc,sizeof(bbuf),bbuf);
225 for (i=0; i<identlen; i += 2)
226 sprintf(hexident+i, "%02x", bbuf[i/2]);
228 hexident[identlen] = 0;
232 if (strlen(ident) > maxidentlen)
233 errx(127, "base directory `%s' plus ident `%s' too long"
234 " (with spare) for socket (max ident %d)\n",
235 run_base, ident, maxidentlen);
237 r = mkdir(run_base, 0700);
239 if (!(errno == EEXIST))
240 err(127,"mkdir %s",run_base);
243 socket_path = m_asprintf("%s/g%s",run_base,ident);
246 static bool check_garbage(void) {
247 struct stat sock_stab, cmd_stab;
250 r = lstat(socket_path, &sock_stab);
252 if ((errno == ENOENT))
253 return 0; /* well, no garbage then */
254 err(127,"stat socket (%s)",socket_path);
257 r = lstat(command, &cmd_stab);
258 if (r) err(127,"lstat command (%s)",command);
263 static void shbang_opts(const char *const **argv_io,
264 const struct cmdinfo *cmdinfos) {
265 myopt(argv_io, cmdinfos);
267 interp = *(*argv_io)++;
268 if (!interp) errx(127,"need interpreter argument");
271 int main(int argc, const char *const *argv) {
272 const char *smashedopt;
275 (smashedopt = argv[1]) &&
276 smashedopt[0]=='-' &&
277 (strchr(smashedopt,' ') || strchr(smashedopt,','))) {
278 /* single argument containg all the options and <interp> */
279 argv += 2; /* eat argv[0] and smashedopt */
280 const char *split_args[MAX_OPTS+1];
282 split_args[split_argc++] = argv[0];
284 if (split_argc >= MAX_OPTS) errx(127,"too many options in combined arg");
285 split_args[split_argc++] = smashedopt;
286 if (smashedopt[0] != '-') /* never true on first iteration */
288 char *delim = strchr(smashedopt,' ');
289 if (!delim) delim = strchr(smashedopt,',');
291 errx(127,"combined arg lacks <interpreter>");
293 smashedopt = delim+1;
295 assert(split_argc <= MAX_OPTS);
296 split_args[split_argc++] = 0;
298 const char *const *split_argv = split_args;
300 shbang_opts(&split_argv, cmdinfos);
302 if (!split_argv) errx(127,"combined arg too many non-option arguments");
304 shbang_opts(&argv, cmdinfos);
308 if (!command) errx(127,"need command argument");
309 if (*argv) errx(127,"too many arguments");
316 printf("socket: %s\n",socket_path);
317 printf("interp: %s\n",interp);
318 printf("command: %s\n",command);