Signal improvements and fixes

CMakeLists.txt

@@ -38,7 +38,7 @@ include (CheckTypeSize)
 include (CheckStructHasMember)
 
 # Default variables for some configuration options
-mark_as_advanced(FORCE ZM_EXTRA_LIBS ZM_MYSQL_ENGINE ZM_NO_MMAP ZM_NO_CRASHTRACE CMAKE_INSTALL_FULL_BINDIR)
+mark_as_advanced(FORCE ZM_EXTRA_LIBS ZM_MYSQL_ENGINE ZM_NO_MMAP CMAKE_INSTALL_FULL_BINDIR)
 set(ZM_RUNDIR "/var/run/zm" CACHE PATH "Location of transient process files, default: /var/run/zm")
 set(ZM_TMPDIR "/tmp/zm" CACHE PATH "Location of temporary files, default: /tmp/zm")
 set(ZM_LOGDIR "/var/log/zm" CACHE PATH "Location of generated log files, default: /var/log/zm")
@@ -57,7 +57,6 @@ set(ZM_WEB_GROUP "" CACHE STRING "The group apache or the local web server runs
 set(ZM_EXTRA_LIBS "" CACHE STRING "A list of optional libraries, separated by semicolons, e.g. ssl;theora")
 set(ZM_MYSQL_ENGINE "InnoDB" CACHE STRING "MySQL engine to use with database, default: InnoDB")
 set(ZM_NO_MMAP "OFF" CACHE BOOL "Set to ON to not use mmap shared memory. Shouldn't be enabled unless you experience problems with the shared memory. default: OFF")
-set(ZM_NO_CRASHTRACE "OFF" CACHE BOOL "Set to ON to skip crash trace code. Useful if zm_signal.cpp fails to compile. default: OFF")
 # Only required for cmakecacheimport:
 set(CMAKE_INSTALL_FULL_BINDIR "${CMAKE_INSTALL_PREFIX}/${CMAKE_INSTALL_BINDIR}" CACHE PATH "Override default binary directory")
 
@@ -72,19 +71,17 @@ set_property(GLOBAL PROPERTY FIND_LIBRARY_USE_LIB64_PATHS ON)
 check_include_file("linux/videodev.h" HAVE_LINUX_VIDEODEV_H)
 check_include_file("linux/videodev2.h" HAVE_LINUX_VIDEODEV2_H)
 check_include_file("execinfo.h" HAVE_EXECINFO_H)
+check_include_file("ucontext.h" HAVE_UCONTEXT_H)
 check_include_file("sys/sendfile.h" HAVE_SYS_SENDFILE_H)
 check_include_file("sys/syscall.h" HAVE_SYS_SYSCALL_H)
 check_function_exists("syscall" HAVE_SYSCALL)
 check_function_exists("sendfile" HAVE_SENDFILE)
 check_function_exists("backtrace" HAVE_DECL_BACKTRACE)
+check_function_exists("backtrace_symbols" HAVE_DECL_BACKTRACE_SYMBOLS)
 check_function_exists("posix_memalign" HAVE_POSIX_MEMALIGN)
-check_function_exists("strsignal" HAVE_STRSIGNAL)
 check_prototype_definition("round" "double round (double x)" "0.0" "math.h" HAVE_DECL_ROUND)
 check_type_size("siginfo_t" HAVE_SIGINFO_T)
 check_type_size("ucontext_t" HAVE_UCONTEXT_T)
-check_type_size("struct sigcontext" HAVE_STRUCT_SIGCONTEXT)
-check_struct_has_member("struct sigcontext" eip signal.h HAVE_STRUCT_SIGCONTEXT_EIP)
-check_struct_has_member("struct sigcontext" rip signal.h HAVE_STRUCT_SIGCONTEXT_RIP)
 
 # *** LIBRARY CHECKS ***
 
@@ -275,14 +272,6 @@ if(HAVE_LIBCRYPTO AND HAVE_OPENSSL_MD5_H AND HAVE_MD5_OPENSSL)
 	set(HAVE_GNUTLS_OPENSSL_H 0)
 endif(HAVE_LIBCRYPTO AND HAVE_OPENSSL_MD5_H AND HAVE_MD5_OPENSSL)
 
-# Disable backtrace if not available
-if((NOT ZM_NO_CRASHTRACE) AND ((NOT HAVE_DECL_BACKTRACE) OR (NOT HAVE_EXECINFO_H)))
-	message(AUTHOR_WARNING " Backtrace is not available. disabling")
-	set(ZM_NO_CRASHTRACE ON)
-	set(HAVE_EXECINFO_H 0)
-	set(HAVE_DECL_BACKTRACE 0)
-endif((NOT ZM_NO_CRASHTRACE) AND ((NOT HAVE_DECL_BACKTRACE) OR (NOT HAVE_EXECINFO_H)))
-
 
 if(NOT ZM_NO_MMAP)
 	set(ZM_MMAP_PERLPACKAGE "Sys::Mmap")

INSTALL

@@ -48,7 +48,6 @@ Advanced:
 	ZM_EXTRA_LIBS		A list of optional libraries, separated by semicolons, e.g. ssl;theora
 	ZM_MYSQL_ENGINE		MySQL engine to use with database, default: InnoDB
 	ZM_NO_MMAP		Set to ON to not use mmap shared memory. Shouldn't be enabled unless you experience problems with the shared memory. default: OFF
-	ZM_NO_CRASHTRACE	Set to ON to skip crash trace code. Useful if zm_signal.cpp fails to compile. default: OFF
 
 
 Useful configuration options provided by cmake:

configure.ac

@@ -235,8 +235,6 @@ AC_STRUCT_TM
 AC_TYPE_SIGNAL
 
 AC_CHECK_TYPES(siginfo_t,,,[#include <signal.h>])
-AC_CHECK_TYPES(struct sigcontext,,,[#include <signal.h>])
-AC_CHECK_MEMBERS([struct sigcontext.eip],,,[#include <signal.h>])
 AC_CHECK_TYPES(ucontext_t,,,[#include <signal.h>])
 
 # Checks for library functions.
@@ -248,7 +246,7 @@ AC_FUNC_STAT
 AC_FUNC_STRFTIME
 AC_FUNC_STRTOD
 AC_FUNC_VPRINTF
-AC_CHECK_FUNCS([gethostbyname gethostname gettimeofday memmove memset mkdir munmap posix_memalign putenv select sendfile socket sqrt strcasecmp strchr strcspn strerror strncasecmp strrchr strsignal strspn strstr strtol strtoull])
+AC_CHECK_FUNCS([gethostbyname gethostname gettimeofday memmove memset mkdir munmap posix_memalign putenv select sendfile socket sqrt strcasecmp strchr strcspn strerror strncasecmp strrchr strspn strstr strtol strtoull])
 AC_CHECK_FUNCS([syscall sleep usleep ioctl ioctlsocket sigaction])
 
 # Other programs
@@ -302,6 +300,7 @@ AC_HEADER_STDC
 AC_CHECK_HEADERS([fcntl.h limits.h memory.h stddef.h stdlib.h string.h strings.h sys/param.h sys/time.h syslog.h unistd.h values.h])
 AC_CHECK_HEADERS([netdb.h netinet/in.h arpa/inet.h sys/ioctl.h sys/socket.h sys/un.h glob.h sys/sendfile.h])
 AC_CHECK_HEADERS(execinfo.h,,,)
+AC_CHECK_HEADERS(ucontext.h,,,)
 AC_CHECK_HEADERS(sys/syscall.h,,,)
 AC_CHECK_HEADERS(pthread.h,,,)
 AC_CHECK_HEADERS(linux/videodev.h,AC_SUBST(ZM_HAS_V4L1,1),AC_SUBST(ZM_HAS_V4L1,0),)
@@ -345,6 +344,7 @@ AC_CHECK_DECLS(gnutls_fingerprint,,AC_MSG_ERROR([zm requires gnutls/gnutls.h - u
 fi
 fi
 AC_CHECK_DECLS(backtrace,,,[#include <execinfo.h>])
+AC_CHECK_DECLS(backtrace_symbols,,,[#include <execinfo.h>])
 
 AC_SUBST(LDFLAGS)
 

src/zm.cpp

@@ -19,4 +19,5 @@
 
 #include "zm.h"
 
-// This space intentionally left blank
+/* This is our argv[0], we need it for backtrace */
+const char* self = 0;

src/zm.h

@@ -32,4 +32,6 @@ double round(double);
 
 #include <stdint.h>
 
+extern const char* self;
+
 #endif // ZM_H

src/zm_signal.cpp

@@ -24,174 +24,152 @@
 #include <string.h>
 #include <stdlib.h>
 
+#define TRACE_SIZE 16
+
 bool zm_reload = false;
+bool zm_terminate = false;
 
-RETSIGTYPE zm_hup_handler( int signal )
+RETSIGTYPE zm_hup_handler(int signal)
 {
-#if HAVE_STRSIGNAL
-	Info( "Got signal %d (%s), reloading", signal, strsignal(signal) );
-#else // HAVE_STRSIGNAL
-	Info( "Got HUP signal, reloading" );
-#endif // HAVE_STRSIGNAL
+	Info("Got signal %d (%s), reloading", signal, strsignal(signal));
 	zm_reload = true;
 }
 
-bool zm_terminate = false;
-
-RETSIGTYPE zm_term_handler( int signal )
+RETSIGTYPE zm_term_handler(int signal)
 {
-#if HAVE_STRSIGNAL
-	Info( "Got signal %d (%s), exiting", signal, strsignal(signal) );
-#else // HAVE_STRSIGNAL
-	Info( "Got TERM signal, exiting" );
-#endif // HAVE_STRSIGNAL
+	Info("Got signal %d (%s), exiting", signal, strsignal(signal));
 	zm_terminate = true;
 }
 
-#define TRACE_SIZE 16
-
-#if HAVE_STRUCT_SIGCONTEXT
-RETSIGTYPE zm_die_handler( int signal, struct sigcontext context )
-#elif ( HAVE_SIGINFO_T && HAVE_UCONTEXT_T )
-#include <ucontext.h>
-RETSIGTYPE zm_die_handler( int signal, siginfo_t *info, void *context )
+#if ( HAVE_SIGINFO_T && HAVE_UCONTEXT_T )
+RETSIGTYPE zm_die_handler(int signal, siginfo_t * info, void *context)
 #else
-RETSIGTYPE zm_die_handler( int signal )
+RETSIGTYPE zm_die_handler(int signal)
 #endif
 {
-    if ( signal == SIGABRT )
-    {
-#if HAVE_STRSIGNAL
-	    Info( "Got signal %d (%s), exiting and forcing backtrace", signal, strsignal(signal) );
-#else // HAVE_STRSIGNAL
-	    Error( "Got signal %d, exiting and forcing backtrace", signal );
-#endif // HAVE_STRSIGNAL
-    }
-    else
-    {
-#if HAVE_STRSIGNAL
-	    Info( "Got signal %d (%s), crashing", signal, strsignal(signal) );
-#else // HAVE_STRSIGNAL
-	    Error( "Got signal %d, crashing", signal );
-#endif // HAVE_STRSIGNAL
-    }
-
-#ifndef ZM_NO_CRASHTRACE
-#if ( ( HAVE_SIGINFO_T && HAVE_UCONTEXT_T ) || HAVE_STRUCT_SIGCONTEXT )
-	void *trace[TRACE_SIZE];
-	int trace_size = 0;
+	void *cr2 = 0;
+	void *ip = 0;
 
-#if HAVE_STRUCT_SIGCONTEXT_EIP
-	Error( "Signal address is %p, from %p", (void *)context.cr2, (void *)context.eip );
+	Error("Got signal %d (%s), crashing", signal, strsignal(signal));
 
-	trace_size = backtrace( trace, TRACE_SIZE );
-	// overwrite sigaction with caller's address
-	trace[1] = (void *)context.eip;
-#elif HAVE_STRUCT_SIGCONTEXT
-	Error( "Signal address is %p, no eip", (void *)context.cr2 );
+	// Get more information if available
+#if ( HAVE_SIGINFO_T && HAVE_UCONTEXT_T )
+	if (info && context) {
 
-	trace_size = backtrace( trace, TRACE_SIZE );
-#else // HAVE_STRUCT_SIGCONTEXT
-	if ( info && context )
-	{
-		ucontext_t *uc = (ucontext_t *)context;
+		Debug(1,
+		      "Signal information: number %d code %d errno %d pid %d uid %d status %d",
+		      signal, info->si_code, info->si_errno, info->si_pid,
+		      info->si_uid, info->si_status);
+
+		ucontext_t *uc = (ucontext_t *) context;
+#if defined(__x86_64__)
+		cr2 = info->si_addr;
+		ip = (void *)(uc->uc_mcontext.gregs[REG_RIP]);
+#else
+		cr2 = info->si_addr;
+		ip = (void *)(uc->uc_mcontext.gregs[REG_EIP]);
+#endif				// defined(__x86_64__)
+
+		// Print the signal address and instruction pointer if available
+		if (ip) {
+			Error("Signal address is %p, from %p", cr2, ip);
+		} else {
+			Error("Signal address is %p, no instruction pointer", cr2);
+		}
+	}
+#endif				// ( HAVE_SIGINFO_T && HAVE_UCONTEXT_T )
 
-		Error( "Signal address is %p, from %p", info->si_addr, uc->uc_mcontext.gregs[REG_EIP] );
 
-		trace_size = backtrace( trace, TRACE_SIZE );
-		// overwrite sigaction with caller's address
-		trace[1] = (void *) uc->uc_mcontext.gregs[REG_EIP];
+	// Print backtrace if enabled and available
+#if ( !defined(ZM_NO_CRASHTRACE) && HAVE_DECL_BACKTRACE && HAVE_DECL_BACKTRACE_SYMBOLS )
+	void *trace[TRACE_SIZE];
+	int trace_size = 0;
+	trace_size = backtrace(trace, TRACE_SIZE);
+
+	char cmd[1024] = "addr2line -e ";
+	char *cmd_ptr = cmd + strlen(cmd);
+	cmd_ptr += snprintf(cmd_ptr, sizeof(cmd) - (cmd_ptr - cmd), "%s", self);
+
+	char **messages = backtrace_symbols(trace, trace_size);
+	// Print the full backtrace
+	for (int i = 0; i < trace_size; i++) {
+		Error("Backtrace %u: %s", i, messages[i]);
+		cmd_ptr +=
+		    snprintf(cmd_ptr, sizeof(cmd) - (cmd_ptr - cmd), " %p",
+			     trace[i]);
 	}
-#endif // HAVE_STRUCT_SIGCONTEXT
-#if HAVE_DECL_BACKTRACE
-    char cmd[1024] = "addr2line -e ";
-    char *cmd_ptr = cmd+strlen(cmd);
-    // Try and extract the binary path from the last backtrace frame
-	char **messages = backtrace_symbols( trace, trace_size );
-    if ( size_t offset = strcspn( messages[trace_size-1], " " ) )
-    {
-        snprintf( cmd_ptr, sizeof(cmd)-(cmd_ptr-cmd), "%s", messages[trace_size-1] );
-        cmd_ptr += offset;
-    }
-    else
-    {
-        cmd_ptr += snprintf( cmd_ptr, sizeof(cmd)-(cmd_ptr-cmd), "/path/to/%s", logId().c_str() );
-    }
-	// skip first stack frame (points here)
-	for ( int i=1; i < trace_size; i++ )
-    {
-		Error( "Backtrace: %s", messages[i] );
-        cmd_ptr += snprintf( cmd_ptr, sizeof(cmd)-(cmd_ptr-cmd), " %p", trace[i] );
-    }
-	Info( "Backtrace complete, please execute the following command for more information" );
-    Info( cmd );
-#endif // HAVE_DECL_BACKTRACE
-#endif // ( HAVE_SIGINFO_T && HAVE_UCONTEXT_T ) || HAVE_STRUCT_SIGCONTEXT
-#endif // ZM_NO_CRASHTRACE
-
-	exit( signal );
+	free(messages);
+
+	Info("Backtrace complete, please execute the following command for more information");
+	Info(cmd);
+#endif				// ( !defined(ZM_NO_CRASHTRACE) && HAVE_DECL_BACKTRACE && HAVE_DECL_BACKTRACE_SYMBOLS )
+
+	exit(signal);
 }
 
-void zmSetHupHandler( SigHandler *handler )
+void zmSetHupHandler(SigHandler * handler)
 {
 	sigset_t block_set;
-	sigemptyset( &block_set );
+	sigemptyset(&block_set);
 	struct sigaction action, old_action;
 
-	action.sa_handler = (SigHandler *)handler;
+	action.sa_handler = (SigHandler *) handler;
 	action.sa_mask = block_set;
-	action.sa_flags = 0;
-	sigaction( SIGHUP, &action, &old_action );
+	action.sa_flags = SA_RESTART;
+	sigaction(SIGHUP, &action, &old_action);
 }
 
-void zmSetTermHandler( SigHandler *handler )
+void zmSetTermHandler(SigHandler * handler)
 {
 	sigset_t block_set;
-	sigemptyset( &block_set );
+	sigemptyset(&block_set);
 	struct sigaction action, old_action;
 
-	action.sa_handler = (SigHandler *)handler;
+	action.sa_handler = (SigHandler *) handler;
 	action.sa_mask = block_set;
-	action.sa_flags = 0;
-	sigaction( SIGTERM, &action, &old_action );
+	action.sa_flags = SA_RESTART;
+	sigaction(SIGTERM, &action, &old_action);
+	sigaction(SIGINT, &action, &old_action);
+	sigaction(SIGQUIT, &action, &old_action);
 }
 
-void zmSetDieHandler( SigHandler *handler )
+void zmSetDieHandler(SigHandler * handler)
 {
 	sigset_t block_set;
-	sigemptyset( &block_set );
+	sigemptyset(&block_set);
 	struct sigaction action, old_action;
 
-	action.sa_handler = (SigHandler *)handler;
 	action.sa_mask = block_set;
+#if ( HAVE_SIGINFO_T && HAVE_UCONTEXT_T )
+	action.sa_sigaction = (void (*)(int, siginfo_t *, void *))handler;
+	action.sa_flags = SA_SIGINFO;
+#else
+	action.sa_handler = (SigHandler *) handler;
 	action.sa_flags = 0;
+#endif
 
-	sigaction( SIGBUS, &action, &old_action );
-	sigaction( SIGSEGV, &action, &old_action );
-	sigaction( SIGABRT, &action, &old_action );
-	sigaction( SIGILL, &action, &old_action );
-	sigaction( SIGFPE, &action, &old_action );
+	sigaction(SIGBUS, &action, &old_action);
+	sigaction(SIGSEGV, &action, &old_action);
+	sigaction(SIGABRT, &action, &old_action);
+	sigaction(SIGILL, &action, &old_action);
+	sigaction(SIGFPE, &action, &old_action);
 }
 
 void zmSetDefaultHupHandler()
 {
-	zmSetHupHandler( (SigHandler *)zm_hup_handler );
+	zmSetHupHandler((SigHandler *) zm_hup_handler);
 }
 
 void zmSetDefaultTermHandler()
 {
-	zmSetTermHandler( (SigHandler *)zm_term_handler );
+	zmSetTermHandler((SigHandler *) zm_term_handler);
 }
 
 void zmSetDefaultDieHandler()
 {
-    if ( config.dump_cores )
-    {
-        // Do nothing
-    }
-    else
-    {
-	    zmSetDieHandler( (SigHandler *)zm_die_handler );
-    }
+	if (config.dump_cores) {
+		// Do nothing
+	} else {
+		zmSetDieHandler((SigHandler *) zm_die_handler);
+	}
 }
-