+++ /dev/null
-/*
- * "Interpreter" that you can put in #! like this
- * #!/usr/bin/cgi-fcgi-perl [<options>]
- *
- * The result is a program which looks, when executed via the #!
- * line, like a CGI program. But the perl script inside will
- * be executed via /usr/bin/perl in fcgi.
- *
- * Options:
- *
- * -g<ident>
- * Use <ident> rather than hex(sha256(<script>))
- * as the basename of the leafname of the fcgi rendezvous
- * socket. If <ident> contains only hex digit characters it
- * ought to be no more than 32 characters.
- *
- * -M<numservers>
- * Start <numservers> instances of the program. This
- * determines the maximum concurrency. (Note that unlike
- * speedy, the specified number of servers is started
- * right away.) The default is 4.
- *
- * cgi-fcgi-perl automatically expires old sockets, including
- * ones where the named perl script is out of date.
- */
-
-/*
- * Uses one of two directories
- * /var/run/user/<UID>/cgi-fcgi-perl/
- * ~/.cgi-fcgi-perl/<node>/
- * and inside there uses these paths
- * s<ident>
- * g<inum>
- *
- * If -M<ident> is not specified then an initial substricg of the
- * lowercase hex of the sha256 of the <script> (ie, our argv[1]) is
- * used. The substring is chosen so that the whole path is 10 bytes
- * shorter than sizeof(sun_path). But always at least 33 characters.
- *
- * <node> is truncated at the first `.' and after the first 32
- * characters.
- *
- * Algorithm:
- * - see if /var/run/user exists
- * if so, lstat /var/run/user/<UID> and check that
- * we own it and it's X700; if not, fail
- * if it's ok then <base> is /var/run/user/<UID>
- * otherwise, look for and maybe create ~/.cgi-fcgi-perl
- * (where ~ is HOME or from getpwuid)
- * and then <base> is ~/.cgi-fcgi-perl/<node>
- * - calculate pathname (checking <ident> length is OK)
- * - check for and maybe create <base>
- * - stat and lstat the <script>
- * - stat the socket and check its timestamp
- * if it is too hold, rename it to g<inum> (where
- * <inum> is in decimal)
- * and run garbage collection
- * - run cgi-fcgi -connect SOCKET SCRIPT
- */
-
-#include "common.h"
-
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-#include <errno.h>
-#include <stdbool.h>
-
-#include <sys/types.h>
-#include <sys/stat.h>
-#include <sys/utsname.h>
-#include <sys/socket.h>
-#include <sys/un.h>
-#include <unistd.h>
-#include <pwd.h>
-#include <err.h>
-
-#include <nettle/sha.h>
-
-#include "myopt.h"
-
-#define die common_die
-#define diee common_diee
-
-#define MINHEXHASH 33
-
-static const char *ident;
-static int numservers;
-
-void diee(const char *m) {
- err(127, "error: %s failed", m);
-}
-
-static void fusagemessage(FILE *f) {
- fprintf(f, "usage: #!/usr/bin/cgi-fcgi-perl [<options>]\n");
-}
-
-void usagemessage(void) { fusagemessage(stderr); }
-
-static void of_help(const struct cmdinfo *ci, const char *val) {
- fusagemessage(stdout);
- if (ferror(stdout)) diee("write usage message to stdout");
- exit(0);
-}
-
-static const struct cmdinfo cmdinfos[]= {
- { "help", 0, .call= of_help },
- { 0, 'g', 1, .sassignto= &ident },
- { 0, 'M', 1, .iassignto= &numservers },
- { 0 }
-};
-
-static uid_t us;
-static const char *run_base, *command, *socket_path;
-
-static bool find_run_base_var_run(void) {
- struct stat stab;
- char *try;
- int r;
-
- try = m_asprintf("%s/%lu", "/var/run/user", us);
- r = lstat(try, &stab);
- if (r<0) {
- if (errno == ENOENT ||
- errno == ENOTDIR ||
- errno == EACCES ||
- errno == EPERM)
- return 0; /* oh well */
- diee("stat /var/run/user/UID");
- }
- if (!S_ISDIR(stab.st_mode)) {
- warnx("%s not a directory, falling back to ~\n", try);
- return 0;
- }
- if (stab.st_uid != us) {
- warnx("%s not owned by uid %lu, falling back to ~\n", try,
- (unsigned long)us);
- return 0;
- }
- if (stab.st_mode & 0077) {
- warnx("%s writeable by group or other, falling back to ~\n", try);
- return 0;
- }
- run_base = m_asprintf("%s/%s", try, "cgi-fcgi-perl");
- return 1;
-}
-
-static bool find_run_base_home(void) {
- struct passwd *pw;
- struct utsname ut;
- char *dot, *try;
- int r;
-
- pw = getpwuid(us); if (!pw) diee("getpwent(uid)");
-
- r = uname(&ut); if (r) diee("uname(2)");
- dot = strchr(ut.nodename, '.');
- if (dot) *dot = 0;
- if (sizeof(ut.nodename) > 32)
- ut.nodename[32] = 0;
-
- try = m_asprintf("%s/%s/%s", pw->pw_dir, ".cgi-fcgi-perl", ut.nodename);
- run_base = try;
- return 1;
-}
-
-static void find_socket_path(void) {
- struct sockaddr_un sun;
- int r;
-
- us = getuid(); if (us==(uid_t)-1) diee("getuid");
-
- find_run_base_var_run() ||
- find_run_base_home() ||
- (abort(),0);
-
- int maxidentlen = sizeof(sun.sun_path) - strlen(run_base) - 10 - 2;
-
- if (!ident) {
- if (maxidentlen < MINHEXHASH)
- errx(127,"cgi-fcgi-perl: base directory `%s'"
- " leaves only %d characters for command name hash"
- " which is too little (<%d)",
- run_base, maxidentlen, MINHEXHASH);
-
- int identlen = maxidentlen > 64 ? 64 : maxidentlen;
- char *hexident = xmalloc(identlen + 2);
- struct sha256_ctx sc;
- unsigned char bbuf[32];
- int i;
-
- sha256_init(&sc);
- sha256_update(&sc,strlen(command)+1,command);
- sha256_digest(&sc,sizeof(bbuf),bbuf);
-
- for (i=0; i<identlen; i += 2)
- sprintf(hexident+i, "%02x", bbuf[i/2]);
-
- hexident[identlen] = 0;
- ident = hexident;
- }
-
- if (strlen(ident) > maxidentlen)
- errx(127, "base directory `%s' plus ident `%s' too long"
- " (with spare) for socket (max ident %d)\n",
- run_base, ident, maxidentlen);
-
- r = mkdir(run_base, 0700);
- if (r) {
- if (!(errno == EEXIST))
- err(127,"mkdir %s",run_base);
- }
-
- socket_path = m_asprintf("%s/g%s",run_base,ident);
-}
-
-static bool check_garbage(void) {
- struct stat sock_stab, cmd_stab;
- int r;
-
- r = lstat(socket_path, &sock_stab);
- if (r) {
- if ((errno == ENOENT))
- return 0; /* well, no garbage then */
- err(127,"stat socket (%s)",socket_path);
- }
-
- r = lstat(command, &cmd_stab);
- if (r) err(127,"lstat command (%s)",command);
-
- return 0;
-}
-
-int main(int argc, const char *const *argv) {
- myopt(&argv, cmdinfos);
-
- command = *argv++;
- if (!command) errx(127,"need command argument");
- if (*argv) errx(127,"too many arguments");
-
- find_socket_path();
-
- check_garbage();
-
- printf(">%s<\n",socket_path);
-
- exit(0);
-}
~ian / chiark-utils.git / blobdiff