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[mod_fastcgi,mod_scgi] consistent waitpid handling (fixes #2791) 

more consistent waitpid() handling, consolidate similar code

If ECHILD received for a given pid, do not retry waitpid() for that pid

x-ref:
  "mod_fastcgi : pid {pid} 1 not found: No child processes"
  https://redmine.lighttpd.net/issues/2791
This commit is contained in:
Glenn Strauss 2017-02-19 13:23:19 -05:00
parent 95a756dcb3
commit fb6b4027c8
2 changed files with 143 additions and 424 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

297
src/mod_fastcgi.c
View File

@ -692,6 +692,47 @@ static int fastcgi_extension_insert(fcgi_exts *ext, buffer *key, fcgi_extension_
}
static int fcgi_proc_waitpid(server *srv, fcgi_extension_host *host, fcgi_proc *proc) {
int rc, status;
if (!proc->is_local) return 0;
if (proc->pid <= 0) return 0;
do {
rc = waitpid(proc->pid, &status, WNOHANG);
} while (-1 == rc && errno == EINTR);
if (0 == rc) return 0; /* child still running */
/* child terminated */
if (-1 == rc) {
/* EINVAL or ECHILD no child processes */
/* should not happen; someone else has cleaned up for us */
log_error_write(srv, __FILE__, __LINE__, "sddss",
"pid ", proc->pid, proc->state,
"not found:", strerror(errno));
} else if (WIFEXITED(status)) {
if (proc->state != PROC_STATE_KILLED) {
log_error_write(srv, __FILE__, __LINE__, "sdb",
"child exited:",
WEXITSTATUS(status), proc->connection_name);
}
} else if (WIFSIGNALED(status)) {
if (WTERMSIG(status) != SIGTERM && WTERMSIG(status) != SIGINT) {
log_error_write(srv, __FILE__, __LINE__, "sd",
"child signalled:", WTERMSIG(status));
}
} else {
log_error_write(srv, __FILE__, __LINE__, "sd",
"child died somehow:", status);
}
proc->pid = 0;
if (proc->state == PROC_STATE_RUNNING) --host->active_procs;
if (proc->state != PROC_STATE_UNSET) --host->max_id;
proc->state = PROC_STATE_DIED;
return 1;
}
INIT_FUNC(mod_fastcgi_init) {
plugin_data *p;
@ -1004,18 +1045,22 @@ static int fcgi_spawn_connection(server *srv,
do {
status = connect(fcgi_fd, fcgi_addr, servlen);
} while (-1 == status && errno == EINTR);
if (-1 == status && errno != ENOENT
&& !buffer_string_is_empty(proc->unixsocket)) {
log_error_write(srv, __FILE__, __LINE__, "sbss",
"unlink", proc->unixsocket,
"after connect failed:", strerror(errno));
unlink(proc->unixsocket->ptr);
}
close(fcgi_fd);
if (-1 == status) {
/* server is not up, spawn it */
pid_t child;
int val;
if (errno != ENOENT &&
!buffer_string_is_empty(proc->unixsocket)) {
unlink(proc->unixsocket->ptr);
}
close(fcgi_fd);
/* reopen socket */
if (-1 == (fcgi_fd = fdevent_socket_cloexec(fcgi_addr->sa_family, SOCK_STREAM, 0))) {
log_error_write(srv, __FILE__, __LINE__, "ss",
@ -1153,56 +1198,26 @@ static int fcgi_spawn_connection(server *srv,
/* father */
close(fcgi_fd);
/* register process */
proc->is_local = 1;
proc->pid = child;
/* wait */
select(0, NULL, NULL, NULL, &tv);
switch (waitpid(child, &status, WNOHANG)) {
case 0:
/* child still running after timeout, good */
break;
case -1:
/* no PID found ? should never happen */
log_error_write(srv, __FILE__, __LINE__, "ss",
"pid not found:", strerror(errno));
return -1;
default:
log_error_write(srv, __FILE__, __LINE__, "sbs",
"the fastcgi-backend", host->bin_path, "failed to start:");
/* the child should not terminate at all */
if (WIFEXITED(status)) {
log_error_write(srv, __FILE__, __LINE__, "sdb",
"child exited with status",
WEXITSTATUS(status), host->bin_path);
log_error_write(srv, __FILE__, __LINE__, "s",
"If you're trying to run your app as a FastCGI backend, make sure you're using the FastCGI-enabled version.\n"
"If this is PHP on Gentoo, add 'fastcgi' to the USE flags.");
} else if (WIFSIGNALED(status)) {
log_error_write(srv, __FILE__, __LINE__, "sd",
"terminated by signal:",
WTERMSIG(status));
if (WTERMSIG(status) == 11) {
log_error_write(srv, __FILE__, __LINE__, "s",
"to be exact: it segfaulted, crashed, died, ... you get the idea." );
log_error_write(srv, __FILE__, __LINE__, "s",
"If this is PHP, try removing the bytecode caches for now and try again.");
}
} else {
log_error_write(srv, __FILE__, __LINE__, "sd",
"child died somehow:",
status);
}
if (0 != fcgi_proc_waitpid(srv, host, proc)) {
log_error_write(srv, __FILE__, __LINE__, "sb",
"fastcgi-backend failed to start:", host->bin_path);
log_error_write(srv, __FILE__, __LINE__, "s",
"If you're trying to run your app as a FastCGI backend, make sure you're using the FastCGI-enabled version. "
"If this is PHP on Gentoo, add 'fastcgi' to the USE flags. "
"If this is PHP, try removing the bytecode caches for now and try again.");
return -1;
}
/* register process */
proc->pid = child;
proc->is_local = 1;
break;
}
} else {
close(fcgi_fd);
proc->is_local = 0;
proc->pid = 0;
@ -2577,8 +2592,6 @@ static int fcgi_restart_dead_procs(server *srv, plugin_data *p, fcgi_extension_h
fcgi_proc *proc;
for (proc = host->first; proc; proc = proc->next) {
int status;
if (p->conf.debug > 2) {
log_error_write(srv, __FILE__, __LINE__, "sbdddd",
"proc:",
@ -2603,67 +2616,16 @@ static int fcgi_restart_dead_procs(server *srv, plugin_data *p, fcgi_extension_h
case PROC_STATE_RUNNING:
break;
case PROC_STATE_OVERLOADED:
if (srv->cur_ts <= proc->disabled_until) break;
proc->state = PROC_STATE_RUNNING;
host->active_procs++;
log_error_write(srv, __FILE__, __LINE__, "sbdb",
"fcgi-server re-enabled:",
host->host, host->port,
host->unixsocket);
break;
case PROC_STATE_DIED_WAIT_FOR_PID:
/* non-local procs don't have PIDs to wait for */
if (!proc->is_local) {
proc->state = PROC_STATE_DIED;
} else {
/* the child should not terminate at all */
if (0 == fcgi_proc_waitpid(srv, host, proc)
&& srv->cur_ts > proc->disabled_until) {
proc->state = PROC_STATE_RUNNING;
host->active_procs++;
for ( ;; ) {
switch(waitpid(proc->pid, &status, WNOHANG)) {
case 0:
/* child is still alive */
if (srv->cur_ts <= proc->disabled_until) break;
proc->state = PROC_STATE_RUNNING;
host->active_procs++;
log_error_write(srv, __FILE__, __LINE__, "sbdb",
"fcgi-server re-enabled:",
host->host, host->port,
host->unixsocket);
break;
case -1:
if (errno == EINTR) continue;
log_error_write(srv, __FILE__, __LINE__, "sd",
"child died somehow, waitpid failed:",
errno);
proc->state = PROC_STATE_DIED;
break;
default:
if (WIFEXITED(status)) {
#if 0
log_error_write(srv, __FILE__, __LINE__, "sdsd",
"child exited, pid:", proc->pid,
"status:", WEXITSTATUS(status));
#endif
} else if (WIFSIGNALED(status)) {
log_error_write(srv, __FILE__, __LINE__, "sd",
"child signaled:",
WTERMSIG(status));
} else {
log_error_write(srv, __FILE__, __LINE__, "sd",
"child died somehow:",
status);
}
proc->state = PROC_STATE_DIED;
break;
}
break;
}
log_error_write(srv, __FILE__, __LINE__, "sbdb",
"fcgi-server re-enabled:",
host->host, host->port,
host->unixsocket);
}
/* fall through if we have a dead proc now */
@ -3128,32 +3090,7 @@ static handler_t fcgi_recv_response(server *srv, handler_ctx *hctx) {
return HANDLER_FINISHED;
case -1:
if (proc->pid && proc->state != PROC_STATE_DIED) {
int status;
/* only fetch the zombie if it is not already done */
switch(waitpid(proc->pid, &status, WNOHANG)) {
case 0:
/* child is still alive */
break;
case -1:
break;
default:
/* the child should not terminate at all */
if (WIFEXITED(status)) {
log_error_write(srv, __FILE__, __LINE__, "sdsd",
"child exited, pid:", proc->pid,
"status:", WEXITSTATUS(status));
} else if (WIFSIGNALED(status)) {
log_error_write(srv, __FILE__, __LINE__, "sd",
"child signaled:",
WTERMSIG(status));
} else {
log_error_write(srv, __FILE__, __LINE__, "sd",
"child died somehow:",
status);
}
if (0 != fcgi_proc_waitpid(srv, host, proc)) {
if (hctx->conf.debug) {
log_error_write(srv, __FILE__, __LINE__, "ssbsdsd",
"--- fastcgi spawning",
@ -3168,8 +3105,6 @@ static handler_t fcgi_recv_response(server *srv, handler_ctx *hctx) {
log_error_write(srv, __FILE__, __LINE__, "s",
"respawning failed, will retry later");
}
break;
}
}
@ -3566,98 +3501,14 @@ TRIGGER_FUNC(mod_fastcgi_handle_trigger) {
host = ex->hosts[n];
for (proc = host->first; proc; proc = proc->next) {
int status;
if (proc->pid == 0) continue;
switch (waitpid(proc->pid, &status, WNOHANG)) {
case 0:
/* child still running after timeout, good */
break;
case -1:
if (errno != EINTR) {
/* no PID found ? should never happen */
log_error_write(srv, __FILE__, __LINE__, "sddss",
"pid ", proc->pid, proc->state,
"not found:", strerror(errno));
}
break;
default:
/* the child should not terminate at all */
if (WIFEXITED(status)) {
if (proc->state != PROC_STATE_KILLED) {
log_error_write(srv, __FILE__, __LINE__, "sdb",
"child exited:",
WEXITSTATUS(status), proc->connection_name);
}
} else if (WIFSIGNALED(status)) {
if (WTERMSIG(status) != SIGTERM) {
log_error_write(srv, __FILE__, __LINE__, "sd",
"child signaled:",
WTERMSIG(status));
}
} else {
log_error_write(srv, __FILE__, __LINE__, "sd",
"child died somehow:",
status);
}
proc->pid = 0;
if (proc->state == PROC_STATE_RUNNING) host->active_procs--;
proc->state = PROC_STATE_DIED;
host->max_id--;
}
fcgi_proc_waitpid(srv, host, proc);
}
fcgi_restart_dead_procs(srv, p, host);
for (proc = host->unused_procs; proc; proc = proc->next) {
int status;
if (proc->pid == 0) continue;
switch (waitpid(proc->pid, &status, WNOHANG)) {
case 0:
/* child still running after timeout, good */
break;
case -1:
if (errno != EINTR) {
/* no PID found ? should never happen */
log_error_write(srv, __FILE__, __LINE__, "sddss",
"pid ", proc->pid, proc->state,
"not found:", strerror(errno));
#if 0
if (errno == ECHILD) {
/* someone else has cleaned up for us */
proc->pid = 0;
proc->state = PROC_STATE_UNSET;
}
#endif
}
break;
default:
/* the child should not terminate at all */
if (WIFEXITED(status)) {
if (proc->state != PROC_STATE_KILLED) {
log_error_write(srv, __FILE__, __LINE__, "sdb",
"child exited:",
WEXITSTATUS(status), proc->connection_name);
}
} else if (WIFSIGNALED(status)) {
if (WTERMSIG(status) != SIGTERM) {
log_error_write(srv, __FILE__, __LINE__, "sd",
"child signaled:",
WTERMSIG(status));
}
} else {
log_error_write(srv, __FILE__, __LINE__, "sd",
"child died somehow:",
status);
}
proc->pid = 0;
if (proc->state == PROC_STATE_RUNNING) host->active_procs--;
if (0 != fcgi_proc_waitpid(srv, host, proc)) {
proc->state = PROC_STATE_UNSET;
host->max_id--;
}
}
}

270
src/mod_scgi.c
View File

@ -536,6 +536,47 @@ static int scgi_extension_insert(scgi_exts *ext, buffer *key, scgi_extension_hos
}
static int scgi_proc_waitpid(server *srv, scgi_extension_host *host, scgi_proc *proc) {
int rc, status;
if (!proc->is_local) return 0;
if (proc->pid <= 0) return 0;
do {
rc = waitpid(proc->pid, &status, WNOHANG);
} while (-1 == rc && errno == EINTR);
if (0 == rc) return 0; /* child still running */
/* child terminated */
if (-1 == rc) {
/* EINVAL or ECHILD no child processes */
/* should not happen; someone else has cleaned up for us */
log_error_write(srv, __FILE__, __LINE__, "sddss",
"pid ", proc->pid, proc->state,
"not found:", strerror(errno));
} else if (WIFEXITED(status)) {
if (proc->state != PROC_STATE_KILLED) {
log_error_write(srv, __FILE__, __LINE__, "sdb",
"child exited:",
WEXITSTATUS(status), host->bin_path);
}
} else if (WIFSIGNALED(status)) {
if (WTERMSIG(status) != SIGTERM && WTERMSIG(status) != SIGINT) {
log_error_write(srv, __FILE__, __LINE__, "sd",
"child signalled:", WTERMSIG(status));
}
} else {
log_error_write(srv, __FILE__, __LINE__, "sd",
"child died somehow:", status);
}
proc->pid = 0;
if (proc->state == PROC_STATE_RUNNING) --host->active_procs;
if (proc->state != PROC_STATE_UNSET) --host->max_id;
proc->state = PROC_STATE_DIED;
return 1;
}
INIT_FUNC(mod_scgi_init) {
plugin_data *p;
@ -774,17 +815,22 @@ static int scgi_spawn_connection(server *srv,
do {
status = connect(scgi_fd, scgi_addr, servlen);
} while (-1 == status && errno == EINTR);
if (-1 == status && errno != ENOENT
&& !buffer_string_is_empty(proc->socket)) {
log_error_write(srv, __FILE__, __LINE__, "sbss",
"unlink", proc->socket,
"after connect failed:", strerror(errno));
unlink(proc->socket->ptr);
}
close(scgi_fd);
if (-1 == status) {
/* server is not up, spawn in */
pid_t child;
int val;
if (!buffer_string_is_empty(proc->socket)) {
unlink(proc->socket->ptr);
}
close(scgi_fd);
/* reopen socket */
if (-1 == (scgi_fd = fdevent_socket_cloexec(scgi_addr->sa_family, SOCK_STREAM, 0))) {
log_error_write(srv, __FILE__, __LINE__, "ss",
@ -909,46 +955,23 @@ static int scgi_spawn_connection(server *srv,
/* father */
close(scgi_fd);
/* register process */
proc->last_used = srv->cur_ts;
proc->is_local = 1;
proc->pid = child;
/* wait */
select(0, NULL, NULL, NULL, &tv);
switch (waitpid(child, &status, WNOHANG)) {
case 0:
/* child still running after timeout, good */
break;
case -1:
/* no PID found ? should never happen */
log_error_write(srv, __FILE__, __LINE__, "ss",
"pid not found:", strerror(errno));
return -1;
default:
/* the child should not terminate at all */
if (WIFEXITED(status)) {
log_error_write(srv, __FILE__, __LINE__, "sd",
"child exited (is this a SCGI binary ?):",
WEXITSTATUS(status));
} else if (WIFSIGNALED(status)) {
log_error_write(srv, __FILE__, __LINE__, "sd",
"child signaled:",
WTERMSIG(status));
} else {
log_error_write(srv, __FILE__, __LINE__, "sd",
"child died somehow:",
status);
}
if (0 != scgi_proc_waitpid(srv, host, proc)) {
log_error_write(srv, __FILE__, __LINE__, "sb",
"scgi-backend failed to start:", host->bin_path);
return -1;
}
/* register process */
proc->pid = child;
proc->last_used = srv->cur_ts;
proc->is_local = 1;
break;
}
} else {
close(scgi_fd);
proc->is_local = 0;
proc->pid = 0;
@ -2095,15 +2118,9 @@ static int scgi_restart_dead_procs(server *srv, plugin_data *p, scgi_extension_h
proc->pid);
}
if (0 == proc->is_local) {
/*
* external servers might get disabled
*
* enable the server again, perhaps it is back again
*/
if ((proc->state == PROC_STATE_DISABLED) &&
(srv->cur_ts - proc->disable_ts > host->disable_time)) {
if (0 == scgi_proc_waitpid(srv, host, proc)
&& proc->state == PROC_STATE_DISABLED
&& srv->cur_ts - proc->disable_ts > host->disable_time) {
proc->state = PROC_STATE_RUNNING;
host->active_procs++;
@ -2112,46 +2129,9 @@ static int scgi_restart_dead_procs(server *srv, plugin_data *p, scgi_extension_h
host->host, host->port,
host->unixsocket);
}
} else {
/* the child should not terminate at all */
int status;
if (proc->state == PROC_STATE_DIED_WAIT_FOR_PID) {
switch(waitpid(proc->pid, &status, WNOHANG)) {
case 0:
/* child is still alive */
break;
case -1:
break;
default:
if (WIFEXITED(status)) {
#if 0
log_error_write(srv, __FILE__, __LINE__, "sdsd",
"child exited, pid:", proc->pid,
"status:", WEXITSTATUS(status));
#endif
} else if (WIFSIGNALED(status)) {
log_error_write(srv, __FILE__, __LINE__, "sd",
"child signaled:",
WTERMSIG(status));
} else {
log_error_write(srv, __FILE__, __LINE__, "sd",
"child died somehow:",
status);
}
proc->state = PROC_STATE_DIED;
break;
}
}
/*
* local servers might died, but we restart them
*
*/
if (proc->state == PROC_STATE_DIED &&
proc->load == 0) {
/* restart the child */
if (proc->state == PROC_STATE_DIED && proc->is_local && 0 == proc->load) {
/* restart local servers */
if (p->conf.debug) {
log_error_write(srv, __FILE__, __LINE__, "ssdsbsdsd",
@ -2169,7 +2149,6 @@ static int scgi_restart_dead_procs(server *srv, plugin_data *p, scgi_extension_h
scgi_proclist_sort_down(srv, host, proc);
}
}
}
return 0;
@ -2521,32 +2500,7 @@ static handler_t scgi_recv_response(server *srv, handler_ctx *hctx) {
scgi_extension_host *host= hctx->host;
if (proc->pid && proc->state != PROC_STATE_DIED) {
int status;
/* only fetch the zombie if it is not already done */
switch(waitpid(proc->pid, &status, WNOHANG)) {
case 0:
/* child is still alive */
break;
case -1:
break;
default:
/* the child should not terminate at all */
if (WIFEXITED(status)) {
log_error_write(srv, __FILE__, __LINE__, "sdsd",
"child exited, pid:", proc->pid,
"status:", WEXITSTATUS(status));
} else if (WIFSIGNALED(status)) {
log_error_write(srv, __FILE__, __LINE__, "sd",
"child signaled:",
WTERMSIG(status));
} else {
log_error_write(srv, __FILE__, __LINE__, "sd",
"child died somehow:",
status);
}
if (0 != scgi_proc_waitpid(srv, host, proc)) {
if (hctx->conf.debug) {
log_error_write(srv, __FILE__, __LINE__, "ssdsbsdsd",
"--- scgi spawning",
@ -2555,10 +2509,7 @@ static handler_t scgi_recv_response(server *srv, handler_ctx *hctx) {
"\n\tcurrent:", 1, "/", host->min_procs);
}
if (scgi_spawn_connection(srv, p, host, proc)) {
/* child died */
proc->state = PROC_STATE_DIED;
} else {
if (0 == scgi_spawn_connection(srv, p, host, proc)) {
scgi_proclist_sort_down(srv, host, proc);
}
@ -2904,46 +2855,7 @@ TRIGGER_FUNC(mod_scgi_handle_trigger) {
host = ex->hosts[n];
for (proc = host->first; proc; proc = proc->next) {
int status;
if (proc->pid == 0) continue;
switch (waitpid(proc->pid, &status, WNOHANG)) {
case 0:
/* child still running after timeout, good */
break;
case -1:
if (errno != EINTR) {
/* no PID found ? should never happen */
log_error_write(srv, __FILE__, __LINE__, "sddss",
"pid ", proc->pid, proc->state,
"not found:", strerror(errno));
}
break;
default:
/* the child should not terminate at all */
if (WIFEXITED(status)) {
if (proc->state != PROC_STATE_KILLED) {
log_error_write(srv, __FILE__, __LINE__, "sdb",
"child exited:",
WEXITSTATUS(status), proc->socket);
}
} else if (WIFSIGNALED(status)) {
if (WTERMSIG(status) != SIGTERM) {
log_error_write(srv, __FILE__, __LINE__, "sd",
"child signaled:",
WTERMSIG(status));
}
} else {
log_error_write(srv, __FILE__, __LINE__, "sd",
"child died somehow:",
status);
}
proc->pid = 0;
if (proc->state == PROC_STATE_RUNNING) host->active_procs--;
proc->state = PROC_STATE_DIED;
host->max_id--;
}
scgi_proc_waitpid(srv, host, proc);
}
scgi_restart_dead_procs(srv, p, host);
@ -3046,52 +2958,8 @@ TRIGGER_FUNC(mod_scgi_handle_trigger) {
}
for (proc = host->unused_procs; proc; proc = proc->next) {
int status;
if (proc->pid == 0) continue;
switch (waitpid(proc->pid, &status, WNOHANG)) {
case 0:
/* child still running after timeout, good */
break;
case -1:
if (errno != EINTR) {
/* no PID found ? should never happen */
log_error_write(srv, __FILE__, __LINE__, "sddss",
"pid ", proc->pid, proc->state,
"not found:", strerror(errno));
#if 0
if (errno == ECHILD) {
/* someone else has cleaned up for us */
proc->pid = 0;
proc->state = PROC_STATE_UNSET;
}
#endif
}
break;
default:
/* the child should not terminate at all */
if (WIFEXITED(status)) {
if (proc->state != PROC_STATE_KILLED) {
log_error_write(srv, __FILE__, __LINE__, "sdb",
"child exited:",
WEXITSTATUS(status), proc->socket);
}
} else if (WIFSIGNALED(status)) {
if (WTERMSIG(status) != SIGTERM) {
log_error_write(srv, __FILE__, __LINE__, "sd",
"child signaled:",
WTERMSIG(status));
}
} else {
log_error_write(srv, __FILE__, __LINE__, "sd",
"child died somehow:",
status);
}
proc->pid = 0;
if (0 != scgi_proc_waitpid(srv, host, proc)) {
proc->state = PROC_STATE_UNSET;
host->max_id--;
}
}
}