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34 * ones where the named script is out of date.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
81 #include <sys/types.h>
83 #include <sys/utsname.h>
84 #include <sys/socket.h>
90 #include <nettle/sha.h>
94 #define die common_die
95 #define diee common_diee
99 static const char *interp, *ident;
100 static int numservers;
102 void diee(const char *m) {
103 err(127, "error: %s failed", m);
106 static void fusagemessage(FILE *f) {
107 fprintf(f, "usage: #!/usr/bin/cgi-fcgi-interp [<options>]\n");
110 void usagemessage(void) { fusagemessage(stderr); }
112 static void of_help(const struct cmdinfo *ci, const char *val) {
113 fusagemessage(stdout);
114 if (ferror(stdout)) diee("write usage message to stdout");
118 static void of_iassign(const struct cmdinfo *ci, const char *val) {
121 errno= 0; v= strtol(val,&ep,10);
122 if (!*val || *ep || errno || v<INT_MIN || v>INT_MAX)
123 badusage("bad integer argument `%s' for --%s",val,ci->olong);
129 static const struct cmdinfo cmdinfos[]= {
130 { "help", 0, .call= of_help },
131 { 0, 'g', 1, .sassignto= &ident },
132 { 0, 'M', 1, .call=of_iassign, .iassignto= &numservers },
137 static const char *run_base, *command, *socket_path;
139 static bool find_run_base_var_run(void) {
144 try = m_asprintf("%s/%lu", "/var/run/user", us);
145 r = lstat(try, &stab);
147 if (errno == ENOENT ||
151 return 0; /* oh well */
152 diee("stat /var/run/user/UID");
154 if (!S_ISDIR(stab.st_mode)) {
155 warnx("%s not a directory, falling back to ~\n", try);
158 if (stab.st_uid != us) {
159 warnx("%s not owned by uid %lu, falling back to ~\n", try,
163 if (stab.st_mode & 0077) {
164 warnx("%s writeable by group or other, falling back to ~\n", try);
167 run_base = m_asprintf("%s/%s", try, "cgi-fcgi-interp");
171 static bool find_run_base_home(void) {
177 pw = getpwuid(us); if (!pw) diee("getpwent(uid)");
179 r = uname(&ut); if (r) diee("uname(2)");
180 dot = strchr(ut.nodename, '.');
182 if (sizeof(ut.nodename) > 32)
185 try = m_asprintf("%s/%s/%s", pw->pw_dir, ".cgi-fcgi-interp", ut.nodename);
190 static void find_socket_path(void) {
191 struct sockaddr_un sun;
194 us = getuid(); if (us==(uid_t)-1) diee("getuid");
196 find_run_base_var_run() ||
197 find_run_base_home() ||
200 int maxidentlen = sizeof(sun.sun_path) - strlen(run_base) - 10 - 2;
203 if (maxidentlen < MINHEXHASH)
204 errx(127,"base directory `%s'"
205 " leaves only %d characters for command name hash"
206 " which is too little (<%d)",
207 run_base, maxidentlen, MINHEXHASH);
209 int identlen = maxidentlen > 64 ? 64 : maxidentlen;
210 char *hexident = xmalloc(identlen + 2);
211 struct sha256_ctx sc;
212 unsigned char bbuf[32];
216 sha256_update(&sc,strlen(interp)+1,interp);
217 sha256_update(&sc,strlen(command)+1,command);
218 sha256_digest(&sc,sizeof(bbuf),bbuf);
220 for (i=0; i<identlen; i += 2)
221 sprintf(hexident+i, "%02x", bbuf[i/2]);
223 hexident[identlen] = 0;
227 if (strlen(ident) > maxidentlen)
228 errx(127, "base directory `%s' plus ident `%s' too long"
229 " (with spare) for socket (max ident %d)\n",
230 run_base, ident, maxidentlen);
232 r = mkdir(run_base, 0700);
234 if (!(errno == EEXIST))
235 err(127,"mkdir %s",run_base);
238 socket_path = m_asprintf("%s/g%s",run_base,ident);
241 static bool check_garbage(void) {
242 struct stat sock_stab, cmd_stab;
245 r = lstat(socket_path, &sock_stab);
247 if ((errno == ENOENT))
248 return 0; /* well, no garbage then */
249 err(127,"stat socket (%s)",socket_path);
252 r = lstat(command, &cmd_stab);
253 if (r) err(127,"lstat command (%s)",command);
258 static void shbang_opts(const char *const **argv_io,
259 const struct cmdinfo *cmdinfos) {
260 myopt(argv_io, cmdinfos);
262 interp = *(*argv_io)++;
263 if (!interp) errx(127,"need interpreter argument");
266 int main(int argc, const char *const *argv) {
267 const char *smashedopt;
270 (smashedopt = argv[1]) &&
271 smashedopt[0]=='-' &&
272 (strchr(smashedopt,' ') || strchr(smashedopt,','))) {
273 /* single argument containg all the options and <interp> */
274 argv += 2; /* eat argv[0] and smashedopt */
275 const char *split_args[MAX_OPTS+1];
278 if (split_argc >= MAX_OPTS) errx(127,"too many options in combined arg");
279 split_args[split_argc++] = smashedopt;
280 if (smashedopt[0] != '-') /* never true on first iteration */
282 char *delim = strchr(smashedopt,' ');
283 if (!delim) delim = strchr(smashedopt,',');
285 errx(127,"combined arg lacks <interpreter>");
287 smashedopt = delim+1;
289 assert(split_argc <= MAX_OPTS);
290 split_args[split_argc++] = 0;
292 const char *const *split_argv = split_args;
294 shbang_opts(&split_argv, cmdinfos);
296 if (!split_argv) errx(127,"combined arg too many non-option arguments");
298 shbang_opts(&argv, cmdinfos);
302 if (!command) errx(127,"need command argument");
303 if (*argv) errx(127,"too many arguments");
309 printf("socket: %s\n",socket_path);
310 printf("interp: %s\n",interp);
311 printf("command: %s\n",command);