initial commit into repository0.0

1 files changed, 152 insertions, 0 deletions

diff --git a/lib/process_manager.cc b/lib/process_manager.cc
new file mode 100644
index 0000000..48bcb03
--- a/dev/null
+++ b/lib/process_manager.cc
@@ -0,0 +1,152 @@
+#ifdef USE_PCH
+ #include "pch.h"
+#else
+ #include <sys/types.h>
+ #include <unistd.h>
+ #include <sys/wait.h>
+ #include <signal.h>
+ #include <errno.h>
+ #include <cassert>
+ #include <string>
+ #include <konforka/exception.h>
+ using namespace std;
+ #include "sitecing/process_manager.h"
+#endif
+
+namespace sitecing {
+
+    process_manager::process_manager()
+	: min_children(1), max_children(MAX_SITECING_SCOREBOARD_SLOTS),
+    min_spare_children(0), max_spare_children(-1), finishing(false),
+    die_humbly(false) {
+    }
+    process_manager::~process_manager() {
+	if(die_humbly)
+	    return;
+	for(int tmp=0;tmp<MAX_SITECING_SCOREBOARD_SLOTS;tmp++) {
+	    scoreboard_slot *sslot = sboard.get_slot(tmp);
+	    if((sslot->state!=scoreboard_slot::state_free) && (sslot->pid>0))
+		kill(sslot->pid,SIGTERM);
+	}
+	collect_dead_souls(true);
+    }
+
+    void process_manager::manage() {
+	while(!finishing) {
+	    manage_children();
+	    // XXX: is it the way it should be?
+	    sleep(10);
+	    wait_for_children();
+	}
+	collect_dead_souls(true);
+    }
+
+    void process_manager::collect_dead_souls(bool actively) {
+	for(int tries=5;(tries>0) && (sboard.count_slots(scoreboard_slot::state_free)!=MAX_SITECING_SCOREBOARD_SLOTS);tries--) {
+	    if(actively) {
+		for(int tmp=0;tmp<MAX_SITECING_SCOREBOARD_SLOTS;tmp++) {
+		    scoreboard_slot *sslot = sboard.get_slot(tmp);
+		    if((sslot->state!=scoreboard_slot::state_free) && (sslot->pid>0))
+			kill(sslot->pid,SIGTERM);
+		}
+	    }
+	    wait_for_children(false);
+	    // XXX: again.. is it the right way?
+	    sleep(1);
+	}
+    }
+
+    void process_manager::wait_for_children(bool hang) {
+	int status;
+	int o = WUNTRACED;
+	if(!hang)
+	    o|=WNOHANG;
+	while(sboard.count_slots(scoreboard_slot::state_free)<MAX_SITECING_SCOREBOARD_SLOTS) {
+	    pid_t pid = waitpid(-1,&status,o);
+	    if(!pid)
+		return;
+	    if(pid<0) {
+		if(errno==EINTR)
+		    return;
+		throw konforka::exception(CODEPOINT,"failed to waitpid()");
+	    }
+	    assert(pid);
+	    int slot = sboard.get_slot_by_pid(pid);
+	    sboard.free_slot(slot);
+	    if(hang)
+		return;
+	}
+    }
+
+    void process_manager::manage_children() {
+	if(!spawn_children())
+	    kill_children();
+	else
+	    sleep(1); // just to get some rest.
+    }
+
+    bool process_manager::spawn_children() {
+	int total_children = 0;
+	int idle_children = 0;
+	for(int tmp=0;tmp<MAX_SITECING_SCOREBOARD_SLOTS;tmp++) {
+	    switch(sboard.get_slot(tmp)->state) {
+		case scoreboard_slot::state_free:
+		    break;
+		case scoreboard_slot::state_idle:
+		    idle_children++;
+		default:
+		    total_children++;
+		    break;
+	    }
+	}
+	int total_lack = 0;
+	if(total_children<min_children)
+	    total_lack = min_children-total_children;
+	int idle_lack = 0;
+	if(idle_children<min_spare_children)
+	    idle_lack = min_spare_children-idle_children;
+	bool rv = false;
+	for(;(idle_lack>0 || total_lack>0) && (total_children<max_children);idle_lack--,total_lack--,total_children++) {
+	    spawn_child();
+	    rv = true;
+	}
+	return rv;
+    }
+
+    bool process_manager::kill_children() {
+	int idle_children = 0;
+	for(int tmp=0;tmp<MAX_SITECING_SCOREBOARD_SLOTS;tmp++) {
+	    if(sboard.get_slot(tmp)->state==scoreboard_slot::state_idle)
+		idle_children++;
+	}
+	int idle_excess = idle_children-max_spare_children;
+	bool rv = false;
+	for(int tmp=0;tmp<MAX_SITECING_SCOREBOARD_SLOTS && idle_excess>0;tmp++) {
+	    scoreboard_slot *sslot = sboard.get_slot(tmp);
+	    if((sslot->state==scoreboard_slot::state_idle) && (sslot->pid>0)) {
+		kill(sslot->pid,SIGTERM);
+		idle_excess--;
+		rv = true;
+	    }
+	}
+	return rv;
+    }
+
+    void process_manager::spawn_child() {
+	int slot = sboard.allocate_slot();
+	pid_t pid = fork();
+	if(pid<0) {
+	    sboard.free_slot(slot);
+	    throw konforka::exception(CODEPOINT,"failed to fork()");
+	}
+	if(!pid) {
+	    // child
+	    sboard.get_slot(slot)->pid = getpid();
+	    process(slot);
+	    _exit(0);
+	}
+	// parent
+	sboard.get_slot(slot)->pid = pid;
+    }
+
+}