* "Interpreter" that you can put in #! like this
* #!/usr/bin/cgi-fcgi-interp [<options>] <interpreter>
* #!/usr/bin/cgi-fcgi-interp [<options>],<interpreter>
+ */
+/*
+ * cgi-fcgi-interp.[ch] - C helpers common to the whole of chiark-utils
+ *
+ * Copyright 2016 Ian Jackson
+ * Copyright 1982,1986,1993 The Regents of the University of California
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
*
+ * You should have received a copy of the GNU General Public
+ * License along with this file; if not, consult the Free Software
+ * Foundation's website at www.fsf.org, or the GNU Project website at
+ * www.gnu.org.
+ *
+ * See below for a BSD 3-clause notice regarding timespeccmp.
+ */
+/*
* The result is a program which looks, when executed via the #!
* line, like a CGI program. But the script inside will be executed
* via <interpreter> in an fcgi context.
* speedy, the specified number of servers is started
* right away.) The default is 4.
*
+ * -c<interval>
+ * Stale server check interval, in seconds. The worker
+ * process group will get a SIGTERM when it is no longer
+ * needed to process new requests. Ideally it would continue
+ * to serve any existing requests. The SIGTERM will arrive no
+ * earlier than <interval> after the last request arrived at
+ * the containing webserver. Default is 300.
+ *
* -D
* Debug mode. Do not actually run program. Instead, print
* out what we would do.
* ~/.cgi-fcgi-interp/<node>/
* and inside there uses these paths
* s<ident>
- * g<inum>
+ * l<ident> used to lock around garbage collection
*
* 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
* - 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
+ * if it is too old, unlink it
+ * - dup stderr, mark no cloexec
+ * - run cgi-fcgi -connect SOCKET \
+ * cgi-fcgi-interp \
+ * --stage2 <was-stderr> <socket> \
+ -c<check-interval> \
+ * \
+ * <interp> <script>
+ *
+ * --stage2 does this:
+ * - dup2 <was-stderr> to fd 2
+ * - open /dev/null and expect fd 1 (and if not, close it)
+ * - become a new process group
+ * - lstat <socket> to find its inum, mtime
+ * - fork/exec <interp> <script>
+ * - periodically lstat <socket> and
+ * if inum, mtime have changed
+ * kill process group (at second iteration)
*/
#include "common.h"
#include <sys/utsname.h>
#include <sys/socket.h>
#include <sys/un.h>
+#include <sys/file.h>
#include <unistd.h>
+#include <fcntl.h>
#include <pwd.h>
#include <err.h>
-
+
#include <nettle/sha.h>
#include "myopt.h"
#define MINHEXHASH 33
static const char *interp, *ident;
-static int numservers, debugmode;
+static int numservers=4, debugmode, stage2;
+static int check_interval=300;
void diee(const char *m) {
err(127, "error: %s failed", m);
{ 0, 'g', 1, .sassignto= &ident },
{ 0, 'M', 1, .call=of_iassign, .iassignto= &numservers },
{ 0, 'D', 0, .iassignto= &debugmode, .arg= 1 },
+ { 0, 'c', 1, .call=of_iassign, .iassignto= &check_interval },
+ { "--stage2",0, 0, .iassignto= &stage2, .arg= 1 },
{ 0 }
};
static uid_t us;
-static const char *run_base, *command, *socket_path;
+static const char *run_base, *script, *socket_path;
+static struct stat sock_stab;
static bool find_run_base_var_run(void) {
struct stat stab;
if (!ident) {
if (maxidentlen < MINHEXHASH)
errx(127,"base directory `%s'"
- " leaves only %d characters for command name hash"
+ " leaves only %d characters for id hash"
" which is too little (<%d)",
run_base, maxidentlen, MINHEXHASH);
sha256_init(&sc);
sha256_update(&sc,strlen(interp)+1,interp);
- sha256_update(&sc,strlen(command)+1,command);
+ sha256_update(&sc,strlen(script)+1,script);
sha256_digest(&sc,sizeof(bbuf),bbuf);
for (i=0; i<identlen; i += 2)
socket_path = m_asprintf("%s/g%s",run_base,ident);
}
+/*
+ * Regarding the macro timespeccmp:
+ *
+ * Copyright (c) 1982, 1986, 1993
+ * The Regents of the University of California. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ * 4. Neither the name of the University nor the names of its contributors
+ * may be used to endorse or promote products derived from this software
+ * without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * @(#)time.h 8.5 (Berkeley) 5/4/95
+ * $FreeBSD: head/sys/sys/time.h 275985 2014-12-21 05:07:11Z imp $
+ */
+#ifndef timespeccmp
+#define timespeccmp(tvp, uvp, cmp) \
+ (((tvp)->tv_sec == (uvp)->tv_sec) ? \
+ ((tvp)->tv_nsec cmp (uvp)->tv_nsec) : \
+ ((tvp)->tv_sec cmp (uvp)->tv_sec))
+#endif /*timespeccmp*/
+
+
+
+static bool stab_isnewer(const struct stat *a, const struct stat *b) {
+#ifdef st_mtime
+ return timespeccmp(&a->st_mtim, &b->st_mtim, >);
+#else
+ return a->st_mtime > &b->st_mtime;
+#endif
+}
+
static bool check_garbage(void) {
- struct stat sock_stab, cmd_stab;
+ struct stat script_stab;
int r;
+ r = lstat(script, &script_stab);
+ if (r) err(127,"lstat script (%s)",script);
+
r = lstat(socket_path, &sock_stab);
if (r) {
if ((errno == ENOENT))
err(127,"stat socket (%s)",socket_path);
}
- r = lstat(command, &cmd_stab);
- if (r) err(127,"lstat command (%s)",command);
+ if (stab_isnewer(&script_stab, &sock_stab))
+ return 1;
+
+ if (S_ISLNK(script_stab.st_mode)) {
+ r = stat(script, &script_stab);
+ if (r) err(127,"stat script (%s0",script);
+
+ if (stab_isnewer(&script_stab, &sock_stab))
+ return 1;
+ }
return 0;
}
+static void tidy_garbage(void) {
+ /* We lock l<ident> and re-check. The effect of this is that each
+ * stale socket is removed only once. So unless multiple updates to
+ * the script happen rapidly, we can't be racing with the cgi-fcgi
+ * (which is recreating the socket */
+ int lockfd = -1;
+ int r;
+
+ const char *lock_path = m_asprintf("%s/l%s",run_base,ident);
+
+ lockfd = open(lock_path, O_CREAT|O_RDWR, 0600);
+ if (lockfd<0) err(127,"create lock (%s)", lock_path);
+
+ r = flock(lockfd, LOCK_EX);
+ if (r) err(127,"lock lock (%s)", lock_path);
+
+ if (check_garbage()) {
+ r = unlink(socket_path);
+ if (r) {
+ if (!(errno == ENOENT))
+ err(127,"remove out-of-date socket (%s)", socket_path);
+ }
+ }
+
+ r = close(lockfd);
+ if (r) errx(127,"close lock (%s)", lock_path);
+}
+
static void shbang_opts(const char *const **argv_io,
const struct cmdinfo *cmdinfos) {
myopt(argv_io, cmdinfos);
shbang_opts(&argv, cmdinfos);
}
- command = *argv++;
- if (!command) errx(127,"need command argument");
+ script = *argv++;
+ if (!script) errx(127,"need script argument");
if (*argv) errx(127,"too many arguments");
find_socket_path();
- check_garbage();
+ bool isgarbage = check_garbage();
if (debugmode) {
printf("socket: %s\n",socket_path);
printf("interp: %s\n",interp);
- printf("command: %s\n",command);
+ printf("script: %s\n",script);
+ printf("garbage: %d\n",isgarbage);
+ exit(0);
}
+ if (isgarbage)
+ tidy_garbage();
+
exit(0);
}
~ian / chiark-utils.git / blobdiff