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.
29 * <options> and <interpreter> can be put into a single argument
30 * to cgi-fcgi-interp, separated by spaces or commas. <interpreter>
33 * cgi-fcgi-interp automatically expires old sockets, including
34 * ones where the named script is out of date.
38 * Uses one of two directories
39 * /var/run/user/<UID>/cgi-fcgi-interp/
40 * ~/.cgi-fcgi-interp/<node>/
41 * and inside there uses these paths
45 * If -M<ident> is not specified then an initial substricg of the
46 * lowercase hex of the sha256 of the <script> (ie, our argv[1]) is
47 * used. The substring is chosen so that the whole path is 10 bytes
48 * shorter than sizeof(sun_path). But always at least 33 characters.
50 * <node> is truncated at the first `.' and after the first 32
54 * - see if /var/run/user exists
55 * if so, lstat /var/run/user/<UID> and check that
56 * we own it and it's X700; if not, fail
57 * if it's ok then <base> is /var/run/user/<UID>
58 * otherwise, look for and maybe create ~/.cgi-fcgi-interp
59 * (where ~ is HOME or from getpwuid)
60 * and then <base> is ~/.cgi-fcgi-interp/<node>
61 * - calculate pathname (checking <ident> length is OK)
62 * - check for and maybe create <base>
63 * - stat and lstat the <script>
64 * - stat the socket and check its timestamp
65 * if it is too hold, rename it to g<inum> (where
66 * <inum> is in decimal)
67 * and run garbage collection
68 * - run cgi-fcgi -connect SOCKET SCRIPT
80 #include <sys/types.h>
82 #include <sys/utsname.h>
83 #include <sys/socket.h>
89 #include <nettle/sha.h>
93 #define die common_die
94 #define diee common_diee
98 static const char *interp, *ident;
99 static int numservers;
101 void diee(const char *m) {
102 err(127, "error: %s failed", m);
105 static void fusagemessage(FILE *f) {
106 fprintf(f, "usage: #!/usr/bin/cgi-fcgi-interp [<options>]\n");
109 void usagemessage(void) { fusagemessage(stderr); }
111 static void of_help(const struct cmdinfo *ci, const char *val) {
112 fusagemessage(stdout);
113 if (ferror(stdout)) diee("write usage message to stdout");
119 static const struct cmdinfo cmdinfos[]= {
120 { "help", 0, .call= of_help },
121 { 0, 'g', 1, .sassignto= &ident },
122 { 0, 'M', 1, .iassignto= &numservers },
127 static const char *run_base, *command, *socket_path;
129 static bool find_run_base_var_run(void) {
134 try = m_asprintf("%s/%lu", "/var/run/user", us);
135 r = lstat(try, &stab);
137 if (errno == ENOENT ||
141 return 0; /* oh well */
142 diee("stat /var/run/user/UID");
144 if (!S_ISDIR(stab.st_mode)) {
145 warnx("%s not a directory, falling back to ~\n", try);
148 if (stab.st_uid != us) {
149 warnx("%s not owned by uid %lu, falling back to ~\n", try,
153 if (stab.st_mode & 0077) {
154 warnx("%s writeable by group or other, falling back to ~\n", try);
157 run_base = m_asprintf("%s/%s", try, "cgi-fcgi-interp");
161 static bool find_run_base_home(void) {
167 pw = getpwuid(us); if (!pw) diee("getpwent(uid)");
169 r = uname(&ut); if (r) diee("uname(2)");
170 dot = strchr(ut.nodename, '.');
172 if (sizeof(ut.nodename) > 32)
175 try = m_asprintf("%s/%s/%s", pw->pw_dir, ".cgi-fcgi-interp", ut.nodename);
180 static void find_socket_path(void) {
181 struct sockaddr_un sun;
184 us = getuid(); if (us==(uid_t)-1) diee("getuid");
186 find_run_base_var_run() ||
187 find_run_base_home() ||
190 int maxidentlen = sizeof(sun.sun_path) - strlen(run_base) - 10 - 2;
193 if (maxidentlen < MINHEXHASH)
194 errx(127,"base directory `%s'"
195 " leaves only %d characters for command name hash"
196 " which is too little (<%d)",
197 run_base, maxidentlen, MINHEXHASH);
199 int identlen = maxidentlen > 64 ? 64 : maxidentlen;
200 char *hexident = xmalloc(identlen + 2);
201 struct sha256_ctx sc;
202 unsigned char bbuf[32];
206 sha256_update(&sc,strlen(interp)+1,interp);
207 sha256_update(&sc,strlen(command)+1,command);
208 sha256_digest(&sc,sizeof(bbuf),bbuf);
210 for (i=0; i<identlen; i += 2)
211 sprintf(hexident+i, "%02x", bbuf[i/2]);
213 hexident[identlen] = 0;
217 if (strlen(ident) > maxidentlen)
218 errx(127, "base directory `%s' plus ident `%s' too long"
219 " (with spare) for socket (max ident %d)\n",
220 run_base, ident, maxidentlen);
222 r = mkdir(run_base, 0700);
224 if (!(errno == EEXIST))
225 err(127,"mkdir %s",run_base);
228 socket_path = m_asprintf("%s/g%s",run_base,ident);
231 static bool check_garbage(void) {
232 struct stat sock_stab, cmd_stab;
235 r = lstat(socket_path, &sock_stab);
237 if ((errno == ENOENT))
238 return 0; /* well, no garbage then */
239 err(127,"stat socket (%s)",socket_path);
242 r = lstat(command, &cmd_stab);
243 if (r) err(127,"lstat command (%s)",command);
248 static void shbang_opts(const char *const **argv_io,
249 const struct cmdinfo *cmdinfos) {
250 myopt(argv_io, cmdinfos);
252 interp = *(*argv_io)++;
253 if (!interp) errx(127,"need interpreter argument");
256 int main(int argc, const char *const *argv) {
257 const char *smashedopt;
260 (smashedopt = argv[1]) &&
261 smashedopt[0]=='-' &&
262 (strchr(smashedopt,' ') || strchr(smashedopt,','))) {
263 /* single argument containg all the options and <interp> */
264 argv += 2; /* eat argv[0] and smashedopt */
265 const char *split_args[MAX_OPTS+1];
268 if (split_argc >= MAX_OPTS) errx(127,"too many options in combined arg");
269 split_args[split_argc++] = smashedopt;
270 if (smashedopt[0] != '-') /* never true on first iteration */
272 char *delim = strchr(smashedopt,' ');
273 if (!delim) delim = strchr(smashedopt,',');
275 errx(127,"combined arg lacks <interpreter>");
277 smashedopt = delim+1;
279 assert(split_argc <= MAX_OPTS);
280 split_args[split_argc++] = 0;
282 const char *const *split_argv = split_args;
284 shbang_opts(&split_argv, cmdinfos);
286 if (!split_argv) errx(127,"combined arg too many non-option arguments");
288 shbang_opts(&argv, cmdinfos);
292 if (!command) errx(127,"need command argument");
293 if (*argv) errx(127,"too many arguments");
299 printf("socket: %s\n",socket_path);
300 printf("interp: %s\n",interp);
301 printf("command: %s\n",command);