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Posted to cvs@httpd.apache.org by tr...@apache.org on 2002/02/01 23:08:34 UTC
cvs commit: httpd-2.0/modules/generators mod_cgid.c
trawick 02/02/01 14:08:34
Modified: . CHANGES
modules/generators mod_cgid.c
Log:
mod_cgid: Add retry logic for when the daemon can't fork fast
enough to keep up with new requests. Start using
HTTP_SERVER_UNAVAILABLE instead of HTTP_INTERNAL_SERVER_ERROR
when we can't talk to the daemon.
Revision Changes Path
1.560 +5 -0 httpd-2.0/CHANGES
Index: CHANGES
===================================================================
RCS file: /home/cvs/httpd-2.0/CHANGES,v
retrieving revision 1.559
retrieving revision 1.560
diff -u -r1.559 -r1.560
--- CHANGES 1 Feb 2002 19:25:13 -0000 1.559
+++ CHANGES 1 Feb 2002 22:08:33 -0000 1.560
@@ -1,5 +1,10 @@
Changes with Apache 2.0.32-dev
+ *) mod_cgid: Add retry logic for when the daemon can't fork fast
+ enough to keep up with new requests. Start using
+ HTTP_SERVER_UNAVAILABLE instead of HTTP_INTERNAL_SERVER_ERROR
+ when we can't talk to the daemon. [Jeff Trawick]
+
*) apxs: LTFLAGS envvar can override default libtool options. Try
"LTFLAGS=' ' apxs -c mod_foo.c" to see what libtool does under
the covers. [Jeff Trawick]
1.112 +73 -34 httpd-2.0/modules/generators/mod_cgid.c
Index: mod_cgid.c
===================================================================
RCS file: /home/cvs/httpd-2.0/modules/generators/mod_cgid.c,v
retrieving revision 1.111
retrieving revision 1.112
diff -u -r1.111 -r1.112
--- mod_cgid.c 28 Jan 2002 18:30:07 -0000 1.111
+++ mod_cgid.c 1 Feb 2002 22:08:34 -0000 1.112
@@ -127,6 +127,7 @@
static apr_pool_t *pcgi;
static int total_modules = 0;
+static pid_t daemon_pid;
/* KLUDGE --- for back-combatibility, we don't have to check Execcgid
* in ScriptAliased directories, which means we need to know if this
@@ -160,6 +161,19 @@
#define DEFAULT_CGID_LISTENBACKLOG 100
#endif
+/* DEFAULT_CONNECT_ATTEMPTS controls how many times we'll try to connect
+ * to the cgi daemon from the thread/process handling the cgi request.
+ * Generally we want to retry when we get ECONNREFUSED since it is
+ * probably because the listen queue is full. We need to try harder so
+ * the client doesn't see it as a 503 error.
+ *
+ * Set this to 0 to continually retry until the connect works or Apache
+ * terminates.
+ */
+#ifndef DEFAULT_CONNECT_ATTEMPTS
+#define DEFAULT_CONNECT_ATTEMPTS 15
+#endif
+
typedef struct {
const char *sockname;
const char *logname;
@@ -596,7 +610,6 @@
static int cgid_init(apr_pool_t *p, apr_pool_t *plog, apr_pool_t *ptemp,
server_rec *main_server)
{
- pid_t pid;
apr_proc_t *procnew;
void *data;
int first_time = 0;
@@ -615,18 +628,18 @@
for (m = ap_preloaded_modules; *m != NULL; m++)
total_modules++;
- if ((pid = fork()) < 0) {
+ if ((daemon_pid = fork()) < 0) {
ap_log_error(APLOG_MARK, APLOG_ERR, errno, main_server,
"Couldn't spawn cgid daemon process");
/* XXX should we return a failure here ? */
}
- else if (pid == 0) {
+ else if (daemon_pid == 0) {
apr_pool_create(&pcgi, p);
cgid_server(main_server);
exit(-1);
}
procnew = apr_pcalloc(p, sizeof(*procnew));
- procnew->pid = pid;
+ procnew->pid = daemon_pid;
procnew->err = procnew->in = procnew->out = NULL;
apr_pool_note_subprocess(p, procnew, kill_after_timeout);
#if APR_HAS_OTHER_CHILD
@@ -850,6 +863,58 @@
return close(fd);
}
+static int connect_to_daemon(int *sdptr, request_rec *r,
+ cgid_server_conf *conf)
+{
+ struct sockaddr_un unix_addr;
+ int sd;
+ int connect_tries;
+ apr_interval_time_t sliding_timer;
+
+ memset(&unix_addr, 0, sizeof(unix_addr));
+ unix_addr.sun_family = AF_UNIX;
+ strcpy(unix_addr.sun_path, conf->sockname);
+
+ connect_tries = 0;
+ sliding_timer = 100000; /* 100 milliseconds */
+ while (1) {
+ ++connect_tries;
+ if ((sd = socket(AF_UNIX, SOCK_STREAM, 0)) < 0) {
+ return log_scripterror(r, conf, HTTP_INTERNAL_SERVER_ERROR, errno,
+ "unable to create socket to cgi daemon");
+ }
+ if (connect(sd, (struct sockaddr *)&unix_addr, sizeof(unix_addr)) < 0) {
+ if (errno == ECONNREFUSED && connect_tries < DEFAULT_CONNECT_ATTEMPTS) {
+ ap_log_rerror(APLOG_MARK, APLOG_DEBUG, errno, r,
+ "connect #%d to cgi daemon failed, sleeping before retry",
+ connect_tries);
+ close(sd);
+ apr_sleep(sliding_timer);
+ if (sliding_timer < 2 * APR_USEC_PER_SEC) {
+ sliding_timer *= 2;
+ }
+ }
+ else {
+ close(sd);
+ return log_scripterror(r, conf, HTTP_SERVICE_UNAVAILABLE, errno,
+ "unable to connect to cgi daemon after multiple tries");
+ }
+ }
+ else {
+ apr_pool_cleanup_register(r->pool, (void *)sd, close_unix_socket,
+ apr_pool_cleanup_null);
+ break; /* we got connected! */
+ }
+ /* gotta try again, but make sure the cgid daemon is still around */
+ if (kill(daemon_pid, 0) != 0) {
+ return log_scripterror(r, conf, HTTP_SERVICE_UNAVAILABLE, errno,
+ "cgid daemon is gone; is Apache terminating?");
+ }
+ }
+ *sdptr = sd;
+ return OK;
+}
+
/****************************************************************
*
* Actual cgid handling...
@@ -865,7 +930,6 @@
int is_included;
int sd;
char **env;
- struct sockaddr_un unix_addr;
apr_file_t *tempsock;
apr_size_t nbytes;
@@ -928,21 +992,9 @@
ap_add_cgi_vars(r);
env = ap_create_environment(r->pool, r->subprocess_env);
- if ((sd = socket(AF_UNIX, SOCK_STREAM, 0)) < 0) {
- return log_scripterror(r, conf, HTTP_INTERNAL_SERVER_ERROR, errno,
- "unable to create socket to cgi daemon");
+ if ((retval = connect_to_daemon(&sd, r, conf)) != OK) {
+ return retval;
}
- apr_pool_cleanup_register(r->pool, (void *)sd, close_unix_socket,
- apr_pool_cleanup_null);
-
- memset(&unix_addr, 0, sizeof(unix_addr));
- unix_addr.sun_family = AF_UNIX;
- strcpy(unix_addr.sun_path, conf->sockname);
-
- if (connect(sd, (struct sockaddr *)&unix_addr, sizeof(unix_addr)) < 0) {
- return log_scripterror(r, conf, HTTP_INTERNAL_SERVER_ERROR, errno,
- "unable to connect to cgi daemon");
- }
send_req(sd, r, argv0, env, CGI_REQ);
@@ -1196,7 +1248,6 @@
int retval;
apr_bucket_brigade *bcgi;
apr_bucket *b;
- struct sockaddr_un unix_addr;
apr_file_t *tempsock = NULL;
cgid_server_conf *conf = ap_get_module_config(r->server->module_config,
&cgid_module);
@@ -1204,21 +1255,9 @@
add_ssi_vars(r, f->next);
env = ap_create_environment(r->pool, r->subprocess_env);
- if ((sd = socket(AF_UNIX, SOCK_STREAM, 0)) < 0) {
- return log_scripterror(r, conf, HTTP_INTERNAL_SERVER_ERROR, 0,
- "unable to create socket to cgi daemon");
+ if ((retval = connect_to_daemon(&sd, r, conf)) != OK) {
+ return retval;
}
- apr_pool_cleanup_register(r->pool, (void *)sd, close_unix_socket,
- apr_pool_cleanup_null);
-
- memset(&unix_addr, 0, sizeof(unix_addr));
- unix_addr.sun_family = AF_UNIX;
- strcpy(unix_addr.sun_path, conf->sockname);
-
- if (connect(sd, (struct sockaddr *)&unix_addr, sizeof(unix_addr)) < 0) {
- return log_scripterror(r, conf, HTTP_INTERNAL_SERVER_ERROR, 0,
- "unable to connect to cgi daemon");
- }
SPLIT_AND_PASS_PRETAG_BUCKETS(*bb, ctx, f->next, rc);
if (rc != APR_SUCCESS) {