* The real interpreter to use. Eg "perl". Need not
* be an absolute path; will be fed to execvp.
*
+ * -G<ident-info>
+ * Add <ident-info> to the unique identifying information for
+ * this fcgi program. May be repeated; order is significant.
+ *
+ * -E<ident-info-env-var>
+ * Look <ident-info-env-var> up in the environment and add
+ * <ident-info-env-var>=<value> as if specified with -G. If
+ * the variable is unset in the environment, it is as if
+ * -G<ident-info-env-var> was specified.
+ *
* -g<ident>
- * Use <ident> rather than hex(sha256(<script>))
+ * Use <ident> rather than hex(sha256(<interp>\0<script>\0))
* 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. <ident> should
* 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 automatically expires old sockets, including
* ones where the named script is out of date.
*/
-
/*
* Uses one of two directories
* /var/run/user/<UID>/cgi-fcgi-interp/
* ~/.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
+ * If -M<ident> is not specified then an initial substring of the
+ * lowercase hex of the sha256 of <interp>\0<script>\0 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.
*
* - check for and maybe create <base>
* - stat and lstat the <script>
* - stat the socket and check its timestamp
- * if it is too old, rename it to g<inum>.<pid> (where
- * <inum> and <pid> are in decimal)
- * and run garbage collection
- * - run cgi-fcgi -connect SOCKET SCRIPT
+ * if it is too old, unlink it
+ * - dup stderr, mark no cloexec
+ * - set CHIARKUTILS_CGIFCGIINTERP_STAGE2=<stderr-copy-fd>
+ * - run cgi-fcgi -connect SOCKET <script>
+ *
+ * When CHIARKUTILS_CGIFCGIINTERP_STAGE2 is set, --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 <interp> and <script> and
+ * if mtime is newer than our start time
+ * 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 <time.h>
+#include <signal.h>
+#include <sys/wait.h>
+
#include <nettle/sha.h>
#include "myopt.h"
#define diee common_diee
#define MINHEXHASH 33
+#define STAGE2_VAR "CHIARKUTILS_CGIFCGIINTERP_STAGE2"
static const char *interp, *ident;
-static int numservers, debugmode;
+static int numservers=4, debugmode;
+static int check_interval=300;
+
+static struct sha256_ctx identsc;
+
+const char *stage2;
void diee(const char *m) {
err(127, "error: %s failed", m);
*ci->iassignto = v;
}
+static void ident_addstring(const struct cmdinfo *ci, const char *string) {
+ /* ci may be 0 and is provided so this can be .call */
+ sha256_update(&identsc,strlen(string)+1,string);
+}
+
+static void off_ident_addenv(const struct cmdinfo *ci, const char *name) {
+ const char *val = getenv(name);
+ if (val) {
+ sha256_update(&identsc,strlen(name),name); /* no nul */
+ sha256_update(&identsc,1,"=");
+ ident_addstring(0,val);
+ } else {
+ ident_addstring(0,name);
+ }
+}
+
#define MAX_OPTS 5
static const struct cmdinfo cmdinfos[]= {
- { "help", 0, .call= of_help },
- { 0, 'g', 1, .sassignto= &ident },
- { 0, 'M', 1, .call=of_iassign, .iassignto= &numservers },
- { 0, 'D', 0, .iassignto= &debugmode, .arg= 1 },
+ { "help", 0, .call=of_help },
+ { 0, 'g', 1, .sassignto= &ident },
+ { 0, 'G', 1, .call= ident_addstring },
+ { 0, 'E', 1, .call= off_ident_addenv },
+ { 0, 'M', 1, .call=of_iassign, .iassignto= &numservers },
+ { 0, 'D', 0, .iassignto= &debugmode, .arg= 1 },
+ { 0, 'c', 1, .call=of_iassign, .iassignto= &check_interval },
{ 0 }
};
static uid_t us;
static const char *run_base, *script, *socket_path;
-static struct stat sock_stab;
+static const char *run_base_mkdir_p;
+static int stderr_copy;
static bool find_run_base_var_run(void) {
struct stat stab;
if (sizeof(ut.nodename) > 32)
ut.nodename[32] = 0;
- try = m_asprintf("%s/%s/%s", pw->pw_dir, ".cgi-fcgi-interp", ut.nodename);
+ run_base_mkdir_p = m_asprintf("%s/%s", pw->pw_dir, ".cgi-fcgi-interp");
+ try = m_asprintf("%/%s", run_base_mkdir_p, ut.nodename);
run_base = try;
return 1;
}
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(interp)+1,interp);
- sha256_update(&sc,strlen(script)+1,script);
- sha256_digest(&sc,sizeof(bbuf),bbuf);
+ ident_addstring(0,interp);
+ ident_addstring(0,script);
+ sha256_digest(&identsc,sizeof(bbuf),bbuf);
for (i=0; i<identlen; i += 2)
sprintf(hexident+i, "%02x", bbuf[i/2]);
run_base, ident, maxidentlen);
r = mkdir(run_base, 0700);
+ if (r && errno==ENOENT && run_base_mkdir_p) {
+ r = mkdir(run_base_mkdir_p, 0700);
+ if (r) err(127,"mkdir %s (since %s was ENOENT)",run_base_mkdir_p,run_base);
+ 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);
+ socket_path = m_asprintf("%s/s%s",run_base,ident);
}
/*
-static bool stab_isnewer(const struct stat *a, const struct stat *b) {
#ifdef st_mtime
+
+static bool stab_isnewer(const struct stat *a, const struct stat *b) {
+ if (debugmode)
+ fprintf(stderr,"stab_isnewer mtim %lu.%06lu %lu.06%lu\n",
+ (unsigned long)a->st_mtim.tv_sec,
+ (unsigned long)a->st_mtim.tv_nsec,
+ (unsigned long)b->st_mtim.tv_sec,
+ (unsigned long)b->st_mtim.tv_nsec);
return timespeccmp(&a->st_mtim, &b->st_mtim, >);
-#else
+}
+
+static void stab_mtimenow(struct stat *out) {
+ int r = clock_gettime(CLOCK_REALTIME, &out->st_mtim);
+ if (r) err(127,"(stage2) clock_gettime");
+ if (debugmode)
+ fprintf(stderr,"stab_mtimenow mtim %lu.%06lu\n",
+ (unsigned long)out->st_mtim.tv_sec,
+ (unsigned long)out->st_mtim.tv_nsec);
+}
+
+#else /* !defined(st_mtime) */
+
+static bool stab_isnewer(const struct stat *a, const struct stat *b) {
+ if (debugmode)
+ fprintf(stderr,"stab_isnewer mtime %lu %lu\n",
+ (unsigned long)a->st_mtime,
+ (unsigned long)b->st_mtime);
return a->st_mtime > &b->st_mtime;
-#endif
}
-static bool check_garbage(void) {
+static void stab_mtimenow(struct stat *out) {
+ out->st_mtime = time(NULL);
+ if (baseline_time.st_mtime == (time_t)-1) err(127,"(stage2) time()");
+ if (debugmode)
+ fprintf(stderr,"stab_mtimenow mtime %lu\n",
+ (unsigned long)out->st_mtime);
+}
+
+#endif /* !defined(st_mtime) */
+
+static bool check_garbage_vs(const struct stat *started) {
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))
- return 0; /* well, no garbage then */
- err(127,"stat socket (%s)",socket_path);
- }
-
- if (stab_isnewer(&script_stab, &sock_stab))
+ if (stab_isnewer(&script_stab, started))
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))
+ if (stab_isnewer(&script_stab, started))
return 1;
}
return 0;
}
-static void tidy_1_garbage(const char *leaf) {
+static bool check_garbage(void) {
+ struct stat sock_stab;
int r;
- struct sockaddr_un sun;
-
- int fd = -1;
-
- memset(&sun,0,sizeof(sun));
- sun.sun_family = AF_UNIX;
- r = snprintf(sun.sun_path, sizeof(sun.sun_path), "%s/%s", run_base, leaf);
- if (r >= sizeof(sun_path))
- goto cannot;
-
- fd = socket(AF_UNIX, SOCK_STREAM, 0);
- if (fd<0) err("create socket for tidying garbage");
-
- r = fcntl(fd, F_SETFL, O_NONBLOCK);
- if (r<0) err("set garbage socket nonblocking");
- r = connect(fd, &sun, sizeof(sun));
+ r = lstat(socket_path, &sock_stab);
if (r) {
- if (errno == EAGAIN || errno == EWOULDBLOCK || errno == EINTR)
- goto cannot;
- if (errno != EINPROGRESS)
- err("connect to garbage socket (%s)", sun.sun_path);
- /* well, EINPROGRESS, let's just carry on and hope write works */
+ if ((errno == ENOENT))
+ return 0; /* well, no garbage then */
+ err(127,"stat socket (%s)",socket_path);
}
- r = write(
-
+ return check_garbage_vs(&sock_stab);
+}
static void tidy_garbage(void) {
- const char *this_garbage =
- m_asprintf("%s/g%lu.%lu", run_base,
- (unsigned long)sock_stab.st_ino,
- (unsigned long)getpid());
+ /* 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;
- r = rename(socket_path, this_garbage);
- if (r) {
- if (!(errno == ENOENT))
- err("rename socket from old runner (from %s to %s)",
- socket_path, this_garbage);
- }
+ const char *lock_path = m_asprintf("%s/l%s",run_base,ident);
- DIR *d = opendir(run_base);
- if (!d) err("open run directory (%d) to clean up garbage", run_base);
- struct dirent *de;
- while ((errno = 0, de = readdir(d))) {
- if (de->d_name[0] != 'g')
- continue;
- tidy_1_garbage(de->d_name);
+ 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);
+ }
}
- if (errno) err("read run directory (%d) to clean up garbage", run_base);
- /*
- (void)r;
- if (r) {
- printf("this_garb: %s\n", this_garbage);
+ r = close(lockfd);
+ if (r) errx(127,"close lock (%s)", lock_path);
+}
+
+static void make_stderr_copy(void) {
+ stderr_copy = dup(2);
+ if (stderr_copy < 0) err(127,"dup stderr (for copy for stage2)");
+}
+
+static void prep_stage2(void) {
+ int r;
+
+ const char *stage2_val = m_asprintf("%d", stderr_copy);
+ r = setenv(STAGE2_VAR, stage2_val, 1);
+ if (r) err(127,"set %s (to announce to stage2)", STAGE2_VAR);
}
static void shbang_opts(const char *const **argv_io,
if (!interp) errx(127,"need interpreter argument");
}
+/* stage2 predeclarations */
+static void record_baseline_time(void);
+static void become_pgrp(void);
+static void setup_handlers(void);
+static void spawn_script(void);
+static void queue_alarm(void);
+static void await_something(void);
+
int main(int argc, const char *const *argv) {
const char *smashedopt;
+ int r;
+
+ stage2 = getenv(STAGE2_VAR);
+ if (stage2) {
+ int stderrfd = atoi(stage2);
+ assert(stderrfd>2);
+
+ r = dup2(stderrfd, 2);
+ assert(r==2);
+
+ r = open("/dev/null",O_WRONLY);
+ if (r<0) err(127,"open /dev/null as stdout");
+ if (r>=3) close(r);
+ else if (r!=1) errx(127,"open /dev/null for stdout gave bad fd %d",r);
+ }
+
+ sha256_init(&identsc);
if (argc>=2 &&
(smashedopt = argv[1]) &&
if (!script) errx(127,"need script argument");
if (*argv) errx(127,"too many arguments");
- find_socket_path();
+ if (!stage2) {
+
+ find_socket_path();
+
+ bool isgarbage = check_garbage();
+
+ if (debugmode) {
+ printf("socket: %s\n",socket_path);
+ printf("interp: %s\n",interp);
+ printf("script: %s\n",script);
+ printf("garbage: %d\n",isgarbage);
+ exit(0);
+ }
- bool havegarbage = check_garbage();
+ if (isgarbage)
+ tidy_garbage();
+
+ make_stderr_copy();
+ prep_stage2();
+
+ execlp("cgi-fcgi",
+ "cgi-fcgi", "-connect", socket_path,
+ script,
+ m_asprintf("%d", numservers),
+ (char*)0);
+ err(127,"exec cgi-fcgi");
+
+ } else { /*stage2*/
+
+ record_baseline_time();
+ become_pgrp();
+ setup_handlers();
+ spawn_script();
+ queue_alarm();
+ await_something();
+ abort();
- if (debugmode) {
- printf("socket: %s\n",socket_path);
- printf("interp: %s\n",interp);
- printf("script: %s\n",script);
- printf("garbage: %d\n",havegarbage);
- exit(0);
}
+}
- if (havegarbage)
- tidy_garbage();
+/* stage2 */
- exit(0);
+/* It is most convenient to handle the recheck timeout, as well as
+ * child death, in signal handlers. Our signals all block each other,
+ * and the main program has signals blocked except in sigsuspend, so
+ * we don't need to worry about async-signal-safety, or errno. */
+
+static struct stat baseline_time;
+static pid_t script_child, stage2_pgrp;
+static bool out_of_date;
+
+static void record_baseline_time(void) {
+ stab_mtimenow(&baseline_time);
+}
+
+static void become_pgrp(void) {
+ int r;
+
+ stage2_pgrp = getpid();
+
+ r = setpgid(0,0);
+ if (r) err(127,"(stage2) setpgid");
+}
+
+static void atexit_handler(void) {
+ int r;
+
+ sighandler_t sigr = signal(SIGTERM,SIG_IGN);
+ if (sigr == SIG_ERR) warn("(stage2) signal(SIGTERM,SIG_IGN)");
+
+ r = killpg(stage2_pgrp,SIGTERM);
+ if (r) warn("(stage) killpg failed");
+}
+
+static void alarm_handler(int dummy) {
+ if (out_of_date)
+ /* second timeout */
+ exit(0); /* transfers control to atexit_handler */
+
+ out_of_date = check_garbage_vs(&baseline_time);
+ queue_alarm();
+}
+
+static void child_handler(int dummy) {
+ for (;;) {
+ int status;
+ pid_t got = waitpid(-1, &status, WNOHANG);
+ if (got == (pid_t)-1) err(127,"(stage2) waitpid");
+ if (got != script_child) {
+ warn("(stage2) waitpid got status %d for unknown child [%lu]",
+ status, (unsigned long)got);
+ continue;
+ }
+ if (WIFEXITED(status)) {
+ int v = WEXITSTATUS(status);
+ if (v) warn("program failed with error exit status %d", v);
+ exit(status);
+ } else if (WIFSIGNALED(status)) {
+ int s = WTERMSIG(status);
+ err(status & 0xff, "program died due to fatal signal %s%s",
+ strsignal(s), WCOREDUMP(status) ? " (core dumped" : "");
+ } else {
+ err(127, "program failed with crazy wait status %#x", status);
+ }
+ }
+ exit(127);
+}
+
+static void setup_handlers(void) {
+ struct sigaction sa;
+ int r;
+
+ r = atexit(atexit_handler);
+ if (r) err(127,"(stage2) atexit");
+
+ sigemptyset(&sa.sa_mask);
+ sigaddset(&sa.sa_mask, SIGALRM);
+ sigaddset(&sa.sa_mask, SIGCHLD);
+ sa.sa_flags = 0;
+
+ r = sigprocmask(SIG_BLOCK, &sa.sa_mask, 0);
+ if (r) err(127,"(stage2) sigprocmask(SIG_BLOCK,)");
+
+ sa.sa_handler = alarm_handler;
+ r = sigaction(SIGALRM, &sa, 0);
+ if (r) err(127,"(stage2) sigaction SIGALRM");
+
+ sa.sa_flags |= SA_NOCLDSTOP;
+ sa.sa_handler = child_handler;
+ r = sigaction(SIGCHLD, &sa, 0);
+ if (r) err(127,"(stage2) sigaction SIGCHLD");
+}
+
+static void spawn_script(void) {
+ script_child = fork();
+ if (script_child == (pid_t)-1) err(127,"(stage2) fork");
+ if (!script_child) {
+ execlp(interp,
+ interp, script, (char*)0);
+ err(127,"(stage2) exec interpreter (`%s', for `%s')\n",interp,script);
+ }
+}
+
+static void queue_alarm(void) {
+ alarm(check_interval);
+}
+
+static void await_something(void) {
+ int r;
+ sigset_t mask;
+ sigemptyset(&mask);
+
+ for (;;) {
+ r = sigsuspend(&mask);
+ assert(r==-1);
+ if (errno != EINTR) err(127,"(stage2) sigsuspend");
+ }
}
~ian / chiark-utils.git / blobdiff