Designate one process to maintain the PID file. Coordinator does that

when Squid runs in SMP mode. The only kid does it when running "mono".
The master process does it when not daemonizing. This change allows SMP
Squid to work with a single PID file.

Broadcast management signals from Coordinator to kids. This change
makes both "squid -k ..." and "kill `cat <PID file>`" work for SMP Squid.

diff --git a/src/ipc/Coordinator.cc b/src/ipc/Coordinator.cc
index b0e4893e249a8f6db6f1a51b7e32bf5bf945a430..6976b1c5ab03f1a6aab6b1fba2c4a0b22310aa5f 100644 (file)
--- a/src/ipc/Coordinator.cc
+++ b/src/ipc/Coordinator.cc
@@ -11,6 +11,7 @@
 
 
 CBDATA_NAMESPACED_CLASS_INIT(Ipc, Coordinator);
+Ipc::Coordinator* Ipc::Coordinator::TheInstance = NULL;
 
 
 Ipc::Coordinator::Coordinator():
@@ -62,3 +63,23 @@ void Ipc::Coordinator::handleRegistrationRequest(const StrandData& strand)
     SendMessage(MakeAddr(strandAddrPfx, strand.kidId),
         Message(mtRegistration, strand.kidId, strand.pid));
 }
+
+void Ipc::Coordinator::broadcastSignal(int sig) const
+{
+    typedef Vector<StrandData>::const_iterator VSDCI;
+    for (VSDCI iter = strands.begin(); iter != strands.end(); ++iter) {
+        debugs(54, 5, HERE << "signal " << sig << " to kid" << iter->kidId <<
+            ", PID=" << iter->pid);
+        kill(iter->pid, sig);
+    }
+}
+
+Ipc::Coordinator* Ipc::Coordinator::Instance()
+{
+    if (!TheInstance)
+        TheInstance = new Coordinator;
+    // XXX: if the Coordinator job quits, this pointer will become invalid
+    // we could make Coordinator death fatal, except during exit, but since
+    // Strands do not re-register, even process death would be pointless.
+    return TheInstance;
+}

diff --git a/src/ipc/Coordinator.h b/src/ipc/Coordinator.h
index c4620dc97026510803e67b36f8d7733dbab8b8df..f2fd75b71a737ad187f2f979dfb25571ac15b635 100644 (file)
--- a/src/ipc/Coordinator.h
+++ b/src/ipc/Coordinator.h
@@ -19,9 +19,14 @@ namespace Ipc
 ///  Coordinates shared activities of Strands (Squid processes or threads)
 class Coordinator: public Port
 {
+public:
+    static Coordinator* Instance();
+
 public:
     Coordinator();
 
+    void broadcastSignal(int sig) const; ///< send sig to registered strands
+
 protected:
     virtual void start(); // Port (AsyncJob) API
     virtual void receive(const Message& message); // Port API
@@ -32,6 +37,7 @@ protected:
 
 private:
     Vector<StrandData> strands; ///< registered processes and threads
+    static Coordinator* TheInstance; ///< the only class instance in existence
 
     CBDATA_CLASS2(Coordinator);
 

diff --git a/src/main.cc b/src/main.cc
index 7a07e1df8b04706e960e4b9d4e84d3aafe482319..0a8cdece3286504ce032fe8891b31dbbcfa52aa9 100644 (file)
--- a/src/main.cc
+++ b/src/main.cc
@@ -127,6 +127,10 @@ static volatile int do_rotate = 0;
 static volatile int do_shutdown = 0;
 static volatile int shutdown_status = 0;
 
+static int RotateSignal = -1;
+static int ReconfigureSignal = -1;
+static int ShutdownSignal = -1;
+
 static void mainRotate(void);
 static void mainReconfigureStart(void);
 static void mainReconfigureFinish(void*);
@@ -198,6 +202,10 @@ SignalEngine::checkEvents(int timeout)
         doShutdown(do_shutdown > 0 ? (int) Config.shutdownLifetime : 0);
         do_shutdown = 0;
     }
+    BroadcastSignalIfAny(DebugSignal);
+    BroadcastSignalIfAny(RotateSignal);
+    BroadcastSignalIfAny(ReconfigureSignal);
+    BroadcastSignalIfAny(ShutdownSignal);
 
     PROF_stop(SignalEngine_checkEvents);
     return EVENT_IDLE;
@@ -556,6 +564,7 @@ void
 rotate_logs(int sig)
 {
     do_rotate = 1;
+    RotateSignal = sig;
 #ifndef _SQUID_MSWIN_
 #if !HAVE_SIGACTION
 
@@ -569,6 +578,7 @@ void
 reconfigure(int sig)
 {
     do_reconfigure = 1;
+    ReconfigureSignal = sig;
 #ifndef _SQUID_MSWIN_
 #if !HAVE_SIGACTION
 
@@ -581,6 +591,7 @@ void
 shut_down(int sig)
 {
     do_shutdown = sig == SIGINT ? -1 : 1;
+    ShutdownSignal = sig;
 #ifdef SIGTTIN
 
     if (SIGTTIN == sig)
@@ -724,10 +735,17 @@ mainReconfigureFinish(void *)
         Config2.onoff.enable_purge = 2;
 
     // parse the config returns a count of errors encountered.
+    const int oldMainProcesses = Config.main_processes;
     if ( parseConfigFile(ConfigFile) != 0) {
         // for now any errors are a fatal condition...
         self_destruct();
     }
+    if (oldMainProcesses != Config.main_processes) {
+        debugs(1, DBG_CRITICAL, "WARNING: Changing 'main_processes' (from " <<
+            oldMainProcesses << " to " << Config.main_processes <<
+            ") is not supported and ignored");
+        Config.main_processes = oldMainProcesses;
+    }
 
     setUmask(Config.umask);
     Mem::Report();
@@ -1400,7 +1418,7 @@ SquidMain(int argc, char **argv)
 
     if (!opt_no_daemon && Config.main_processes > 1) {
         if (KidIdentifier == Config.main_processes + 1)
-            AsyncJob::AsyncStart(new Ipc::Coordinator);
+            AsyncJob::AsyncStart(Ipc::Coordinator::Instance());
         else if (KidIdentifier != 0)
             AsyncJob::AsyncStart(new Ipc::Strand);
     }
@@ -1826,10 +1844,12 @@ SquidShutdown()
 
 #endif
 
-    if (Config.pidFilename && strcmp(Config.pidFilename, "none") != 0) {
-        enter_suid();
-        safeunlink(Config.pidFilename, 0);
-        leave_suid();
+    if (IsPidFileMaintainer()) {
+        if (Config.pidFilename && strcmp(Config.pidFilename, "none") != 0) {
+            enter_suid();
+            safeunlink(Config.pidFilename, 0);
+            leave_suid();
+        }
     }
 
     debugs(1, 1, "Squid Cache (Version " << version_string << "): Exiting normally.");

diff --git a/src/protos.h b/src/protos.h
index 4ff74b8fa7a1f45f10cc155717db9d82d3322d91..b60f915e53c315471fcb1175787982251b513a35 100644 (file)
--- a/src/protos.h
+++ b/src/protos.h
@@ -575,6 +575,10 @@ SQUIDCEXTERN void squid_signal(int sig, SIGHDLR *, int flags);
 SQUIDCEXTERN pid_t readPidFile(void);
 SQUIDCEXTERN void keepCapabilities(void);
 
+SQUIDCEXTERN void BroadcastSignalIfAny(int& sig);
+SQUIDCEXTERN bool IsPidFileMaintainer();
+SQUIDCEXTERN int DebugSignal;
+
 /* AYJ debugs function to show locations being reset with memset() */
 SQUIDCEXTERN void *xmemset(void *dst, int, size_t);
 

diff --git a/src/tools.cc b/src/tools.cc
index 91c2110e8162c8547ffd69a20672ed0d450e9e4d..df4eeeac01d615a6dfc12904ec1e4d78ffa16100 100644 (file)
--- a/src/tools.cc
+++ b/src/tools.cc
@@ -41,6 +41,8 @@
 #include "SquidMath.h"
 #include "SquidTime.h"
 #include "ip/IpIntercept.h"
+#include "ipc/Kids.h"
+#include "ipc/Coordinator.h"
 
 #if HAVE_SYS_PRCTL_H
 #include <sys/prctl.h>
@@ -64,6 +66,7 @@ extern void log_trace_done();
 extern void log_trace_init(char *);
 #endif
 static void restoreCapabilities(int keep);
+int DebugSignal = -1;
 
 #ifdef _SQUID_LINUX_
 /* Workaround for crappy glic header files */
@@ -397,6 +400,17 @@ death(int sig)
     abort();
 }
 
+void
+BroadcastSignalIfAny(int& sig)
+{
+    if (sig > 0) {
+        if (!opt_no_daemon && Config.main_processes > 1) {
+            if (KidIdentifier == Config.main_processes + 1)
+                Ipc::Coordinator::Instance()->broadcastSignal(sig);
+        }
+        sig = -1;
+    }
+}
 
 void
 sigusr2_handle(int sig)
@@ -404,6 +418,8 @@ sigusr2_handle(int sig)
     static int state = 0;
     /* no debugs() here; bad things happen if the signal is delivered during _db_print() */
 
+    DebugSignal = sig;
+
     if (state == 0) {
 #ifndef MEM_GEN_TRACE
         Debug::parseOptions("ALL,7");
@@ -790,6 +806,26 @@ no_suid(void)
 #endif
 }
 
+bool
+IsPidFileMaintainer()
+{
+    if (!opt_no_daemon && Config.main_processes > 0) {
+        if (Config.main_processes > 1) {
+            // multiple kids delegate PID file maintanence to the coordinator
+            if (KidIdentifier <= Config.main_processes)
+                return false;
+        } else {
+            // master process does not maintain PID file when
+            // Config.main_processes == 1
+            if (KidIdentifier == 0)
+                return false;
+        }
+    }
+
+    // if there are no kids, then the master process maintains the PID file
+    return true;
+}
+
 void
 writePidFile(void)
 {
@@ -798,6 +834,9 @@ writePidFile(void)
     mode_t old_umask;
     char buf[32];
 
+    if (!IsPidFileMaintainer())
+        return;
+
     if ((f = Config.pidFilename) == NULL)
         return;