#include <stdio.h>
#include <string.h>
#include <sys/select.h>
-#include <signal.h>
#include <sys/wait.h>
#include "opensrf/utils.h"
@param routerDomain Domain of the router.
Tell the router that you're open for business so that it can route requests to you.
+
+ Called only by the parent process.
*/
static void osrf_prefork_send_router_registration(
const char* appname, const char* routerName, const char* routerDomain ) {
free(jid);
}
-/** parses a single "complex" router configuration chunk */
-static void osrf_prefork_parse_router_chunk(const char* appname, jsonObject* routerChunk) {
+/* parses a single "complex" router configuration chunk */
+// Called only by the parent process
+static void osrf_prefork_parse_router_chunk(const char* appname, const jsonObject* routerChunk) {
const char* routerName = jsonObjectGetString(jsonObjectGetKeyConst(routerChunk, "name"));
const char* domain = jsonObjectGetString(jsonObjectGetKeyConst(routerChunk, "domain"));
}
}
+/**
+ @brief Register the application with one or more routers, according to the configuration.
+ @param appname Name of the application.
+
+ Called only by the parent process.
+*/
static void osrf_prefork_register_routers( const char* appname ) {
jsonObject* routerInfo = osrfConfigGetValueObject(NULL, "/routers/router");
int i;
for(i = 0; i < routerInfo->size; i++) {
- jsonObject* routerChunk = jsonObjectGetIndex(routerInfo, i);
+ const jsonObject* routerChunk = jsonObjectGetIndex(routerInfo, i);
if(routerChunk->type == JSON_STRING) {
/* this accomodates simple router configs */
routerName);
osrf_prefork_send_router_registration(appname, routerName, domain);
+ free( routerName );
+ free( domain );
} else {
osrf_prefork_parse_router_chunk(appname, routerChunk);
}
}
+
+ jsonObjectFree( routerInfo );
}
+/**
+ @brief Initialize a child process.
+ @param child Pointer to the prefork_child representing the new child process.
+ @return Zero if successful, or -1 if not.
+
+ Called only by child processes. Actions:
+ - Connect to one or more cache servers
+ - Reconfigure logger, if necessary
+ - Discard parent's Jabber connection and open a new one
+ - Dynamically call an application-specific initialization routine
+ - Change the command line as reported by ps
+*/
static int prefork_child_init_hook(prefork_child* child) {
if(!child) return -1;
osrfLogDebug( OSRF_LOG_MARK, "Child init hook for child %d", child->pid);
+ // Connect to cache server(s).
osrfSystemInitCache();
char* resc = va_list_to_string("%s_drone", child->appname);
- /* if we're a source-client, tell the logger now that we're a new process*/
+ // If we're a source-client, tell the logger now that we're a new process.
char* isclient = osrfConfigGetValue(NULL, "/client");
if( isclient && !strcasecmp(isclient,"true") )
osrfLogSetIsClient(1);
free(isclient);
- /* we want to remove traces of our parent's socket connection
- * so we can have our own */
+ // Remove traces of our parent's socket connection so we can have our own.
osrfSystemIgnoreTransportClient();
+ // Connect to Jabber
if(!osrfSystemBootstrapClientResc( NULL, NULL, resc )) {
osrfLogError( OSRF_LOG_MARK, "Unable to bootstrap client for osrf_prefork_run()");
free(resc);
free(resc);
+ // Dynamically call the application-specific initialization function
+ // from a previously loaded shared library.
if( ! osrfAppRunChildInit(child->appname) ) {
osrfLogDebug(OSRF_LOG_MARK, "Prefork child_init succeeded\n");
} else {
return -1;
}
+ // Change the command line as reported by ps
set_proc_title( "OpenSRF Drone [%s]", child->appname );
return 0;
}
+// Called only by a child process
static void prefork_child_process_request(prefork_child* child, char* data) {
if( !child ) return;
}
/**
- @brief Spawn a new child process.
+ @brief Spawn a new child process and put it in the idle list.
@param forker Pointer to the prefork_simple that will own the process.
@return Pointer to the new prefork_child, or not at all.
}
}
+/**
+ @brief Terminate a child process.
+ @param child Pointer to the prefork_child representing the child process.
+
+ Called only by child processes. Dynamically call an application-specific shutdown
+ function from a previously loaded shared library; then exit.
+*/
static void osrf_prefork_child_exit(prefork_child* child) {
osrfAppRunExitCode();
exit(0);
}
+/**
+ @brief Launch all the child processes, putting them in the idle list.
+ @param forker Pointer to the prefork_simple that will own the children.
+
+ Called only by the parent process (in order to become a parent).
+*/
static void prefork_launch_children( prefork_simple* forker ) {
if(!forker) return;
int c = 0;
launch_child( forker );
}
-
/**
@brief Signal handler for SIGCHLD: note that a child process has terminated.
@param sig The value of the trapped signal; always SIGCHLD.
child_dead = 1;
}
-
/**
@brief Replenish the collection of child processes, after one has terminated.
@param forker Pointer to the prefork_simple that manages the child processes.
- This function is called when we notice (via a signal handler) that a child
- process has died.
+ The parent calls this function when it notices (via a signal handler) that
+ a child process has died.
- Spawn a new child process to replace each of the terminated ones.
+ Wait on the dead children so that they won't be zombies. Spawn new ones as needed
+ to maintain at least a minimum number.
*/
void reap_children( prefork_simple* forker ) {
// Bury the children so that they won't be zombies. WNOHANG means that waitpid() returns
// immediately if there are no waitable children, instead of waiting for more to die.
// Ignore the return code of the child. We don't do an autopsy.
- while( (child_pid = waitpid(-1, NULL, WNOHANG)) > 0)
+ while( (child_pid = waitpid(-1, NULL, WNOHANG)) > 0) {
+ --forker->current_num_children;
del_prefork_child( forker, child_pid );
+ }
- /* Spawn more children as needed to maintain a minimum brood. */
+ // Spawn more children as needed.
while( forker->current_num_children < forker->min_children )
launch_child( forker );
}
// Grab the prefork_child at the head of the idle list
cur_child = forker->idle_list;
forker->idle_list = cur_child->next;
+ cur_child->next = NULL;
osrfLogInternal( OSRF_LOG_MARK,
"Searching for available child. cur_child->pid = %d", cur_child->pid );
osrfLogDebug( OSRF_LOG_MARK, "Launching new child with current_num = %d",
forker->current_num_children );
- prefork_child* new_child = launch_child( forker );
- if( new_child ) {
+ launch_child( forker ); // Put a new child into the idle list
+ if( forker->idle_list ) {
+
+ // Take the new child from the idle list
+ prefork_child* new_child = forker->idle_list;
+ forker->idle_list = new_child->next;
+ new_child->next = NULL;
osrfLogDebug( OSRF_LOG_MARK, "Writing to new child fd %d : pid %d",
new_child->write_data_fd, new_child->pid );
- if(write(new_child->write_data_fd, msg_data, strlen(msg_data) + 1) >= 0 ) {
- forker->first_child = new_child->next;
- add_prefork_child( forker, new_child );
- honored = 1;
- } else {
+ int written = write(
+ new_child->write_data_fd, msg_data, strlen(msg_data) + 1);
+ if( written < 0 ) {
// This child appears to be dead or unusable. Discard it.
osrfLogWarning( OSRF_LOG_MARK, "Write returned error %d: %s",
errno, strerror( errno ) );
kill( cur_child->pid, SIGKILL );
- osrfLogWarning( OSRF_LOG_MARK, "Write returned error %d: %s",
- errno, strerror( errno ) );
del_prefork_child( forker, cur_child->pid );
+ } else {
+ add_prefork_child( forker, new_child );
+ honored = 1;
}
}
message_free( cur_msg );
} /* end top level listen loop */
-
}
in the best case, this will be faster than calling usleep(x), and
in the worst case it won't be slower and will do less logging...
*/
+/**
+ @brief See if any children have become available.
+ @param forker Pointer to the prefork_simple that owns the children.
+ @param forever Boolean: true if we should wait indefinitely.
+ @return
+
+ Call select() for all the children in the active list. Read each active file
+ descriptor and move the corresponding child to the idle list.
+
+ If @a forever is true, wait indefinitely for input. Otherwise return immediately if
+ there are no active file descriptors.
+*/
static void check_children( prefork_simple* forker, int forever ) {
if( child_dead )
if( NULL == forker->first_child ) {
// If forever is true, then we're here because we've run out of idle
- // processes, so there should be some active ones around. Otherwise
- // the children may all be idle, and that's okay.
+ // processes, so there should be some active ones around.
+ // If forever is false, then the children may all be idle, and that's okay.
if( forever )
osrfLogError( OSRF_LOG_MARK, "No active child processes to check" );
return;
}
}
+/**
+ @brief Service up a set maximum number of requests; then shut down.
+ @param child Pointer to the prefork_child representing the child process.
+
+ Called only by child process.
+ Enter a loop, for up to max_requests iterations. On each iteration:
+ - Wait indefinitely for a request from the parent.
+ - Service the request.
+ - Increment a counter. If the limit hasn't been reached, notify the parent that you
+ are available for another request.
+
+ After exiting the loop, shut down and terminate the process.
+*/
static void prefork_child_wait( prefork_child* child ) {
int i,n;
cur_child->prev->next = cur_child->next;
cur_child->next->prev = cur_child->prev;
}
- --forker->current_num_children;
+ //--forker->current_num_children;
//Destroy the node
prefork_child_free( forker, cur_child );
else
forker->idle_list = cur_child->next;
- --forker->current_num_children;
+ //--forker->current_num_children;
//Destroy the node
prefork_child_free( forker, cur_child );
prefork_child_free( prefork, child );
child = temp;
}
- prefork->current_num_children = 0;
+ //prefork->current_num_children = 0;
// Physically free the free list of prefork_children.
child = prefork->free_list;
// children will survive a bit longer.
sleep( 1 );
while( (waitpid(-1, NULL, WNOHANG)) > 0) {
- ; // Another one died...go around again
+ --prefork->current_num_children;
}
free(prefork->appname);
projects / OpenSRF.git / commitdiff