Fixed a race. Kernel could send iPAQ sleeping while opiealarm had not yet

set the RTC alarm.

1 files changed, 27 insertions, 7 deletions

diff --git a/core/opiealarm/opiealarm.c b/core/opiealarm/opiealarm.c
index ce0103e..d96ffaf 100644
--- a/core/opiealarm/opiealarm.c
+++ b/core/opiealarm/opiealarm.c
@@ -1,360 +1,380 @@
 /* opiealarm.c
 *  This program is for extracting the event time/date out
 *  of /etc/resumeat and setting the RTC alarm to that time/date.
 *  It is designed to run via a script just before the iPaq
 *  is suspended.
 * 
 *  Roughly based on ipaqalarm from Benjamin Long
 *
 *  written by Robert Griebl <sandman@handhelds.org>
 */
 
 #include <stdio.h>
 #include <linux/rtc.h>
 #include <sys/ioctl.h>
 #include <sys/time.h>
 #include <sys/types.h>
 #include <fcntl.h>
 #include <unistd.h>
 #include <errno.h>
 #include <time.h>
 #include <stdlib.h>
 #include <syslog.h>
 #include <signal.h>
 #include <errno.h>
 #include <string.h>
 
 
         #define PIDFILE "/var/run/opiealarm.pid"
         #define APMFILE         "/proc/apm"
 
 FILE *log; // debug only
 
 int resume ( int resuspend );
 int suspend ( int fix_rtc );
 int main ( int argc, char **argv );
 int fork_with_pidfile ( void );
 int kill_with_pidfile ( void );
 void remove_pidfile ( void );
 void usage ( void );
 void sig_handler ( int sig );
 void error_msg_and_die ( int perr, const char *msg );
 int onac ( void );
 
 static int opiealarm_was_running;
 
+static pid_t startpid = 0;
+
 
 void log_msg ( const char *msg )
 {
         if ( log ) {
                 fprintf ( log, msg );
                 fflush ( log );
         }
 }
 
 void error_msg_and_die ( int perr, const char *msg )
 {
         if ( perr )
                 log_msg ( strerror ( errno ));
         log_msg ( msg );
 
+        if ( getpid ( ) != startpid ) 
+                kill ( startpid, SIGUSR1 );
+
                 while ( 1 )     // pretend we are waiting on RTC, so opiealarm -r can kill us
                 sleep ( 1 );
 }
 
 
 void sig_handler ( int sig )
 {
-        log_msg ( "GOT SIGNAL -> EXITING\n" );
-        fclose ( log );
+        if ( log ) {
+                log_msg ( "GOT SIGNAL -> EXITING\n" );
+                fclose ( log );
+        }
         remove_pidfile ( );
         exit ( 0 );
 }
 
+void sig_handler_parent ( int sig )
+{
+        exit ( 0 );
+}
+
 void usage ( void )
 {
         fprintf ( stderr, "Usage: opiealarm -s [-f] | -r [-a]\n\n" );
         fprintf ( stderr, "\t-s\tSuspend mode: set RTC alarm\n" );
         fprintf ( stderr, "\t-f    \tFix RTC, if RTC and system have more than 5sec difference (suspend mode)\n" );
         fprintf ( stderr, "\t-r\tResume mode: kill running opiealarm\n" );
         fprintf ( stderr, "\t-a <x>\tResuspend in <x> seconds (resume mode)\n\n" );
         exit ( 1 );
 }
 
 int fork_with_pidfile ( void )
 {
         FILE *fp;
         pid_t pid;
         
         pid = fork ( );
         
-        if ( pid > 0 )
+        if ( pid > 0 ) {
+                signal ( SIGUSR1, sig_handler_parent );
+                while ( 1 )
+                        sleep ( 1000 );
                 exit ( 0 );
+        }
         else if ( pid < 0 ) {
                 perror ( "forking failed" );
                 return 0;
         }
 
         signal ( SIGTERM, sig_handler );
         signal ( SIGINT,  sig_handler );
 
         // save pid
         if (( fp = fopen ( PIDFILE, "w" ))) {
                 fprintf ( fp, "%d", getpid ( ));
                 fclose ( fp );
 
                 // detach
                 close ( 0 );
                 close ( 1 );
                 close ( 2 );
 
                 setpgid ( 0, 0 );
 
                 return 1;
         }
         else {
                 perror ( PIDFILE );
                 return 0;
         }
 }
 
 int kill_with_pidfile ( void )
 {
         FILE *fp;
         pid_t pid;
 
         if (( fp = fopen ( PIDFILE, "r" ))) {
                 if ( fscanf ( fp, "%d", &pid ) == 1 )
                         return ( kill ( pid, SIGTERM ) == 0 ) ? 1 : 0;
                 fclose ( fp );
         }
         return 0;
 }
 
 void remove_pidfile ( void )
 {
         unlink ( PIDFILE );
         
         signal ( SIGTERM, SIG_DFL );
                 signal ( SIGINT,  SIG_DFL );
 }
 
 
 int main ( int argc, char **argv ) 
 {
         int mode = 0;
         int ac_resusp = 0;
         int fix_rtc = 0;
         int opt;
 
         while (( opt = getopt ( argc, argv, "a:frs" )) != EOF ) {
                 switch ( opt ) {
                         case 's':
                                 mode = 's';
                                 break;
                         case 'r':
                                 mode = 'r';
                                 break;
                         case 'a':
                                 ac_resusp = atoi ( optarg );
                                 if ( ac_resusp < 30 ) {
                                         ac_resusp = 120;
                                         
                                         fprintf ( stderr, "Warning: resuspend timeout must be >= 30 sec. -- now set to 120 sec\n" );
                                 }
                                 break;
                         case 'f':
                                 fix_rtc = 1;
                                         break;                  
                         default:
                                 usage ( );
                 }
                 }
         
         if ( geteuid ( ) != 0 ) {
                 fprintf ( stderr, "You need root priviledges to run opiealarm." );
                 return 2;
         }
         
         if ( !mode )
                 usage ( );
 
         // kill running opiealarm
+        startpid = getpid ( );
         opiealarm_was_running = kill_with_pidfile ( );
         remove_pidfile ( );
 
         switch ( mode ) {
                 case 'r': return resume ( ac_resusp );
                 case 's':
                 default : return suspend ( fix_rtc );
         }
         return 0;
         }       
                 
 
+
 int suspend ( int fix_rtc )
 {
         FILE *fp;
         char buf [64];
         time_t alrt, syst, rtct;
         struct tm alr, sys, rtc;
         int fd;
         int rtc_sys_diff;
         
         
         if ( !fork_with_pidfile ( ))
                 return 3;
                 
         log = fopen ( "/tmp/opiealarm.log", "w" ); 
         log_msg ( "STARTING\n" );
         
 
-
         if (!( fp = fopen ( "/etc/resumeat", "r" ))) 
                 error_msg_and_die ( 1, "/etc/resumeat" );
         
         if ( !fgets ( buf, sizeof( buf ) - 1, fp ))
                 error_msg_and_die ( 1, "/etc/resumeat" );
 
         fclose ( fp );
         
         alrt = atoi ( buf );
         
         if ( alrt == 0 )
                 error_msg_and_die ( 0, "/etc/resumeat contains an invalid time description" );
         
-        /* subtract 5 sec from event time... */
-        alrt -= 5;
+                alrt -= 5; // wake up 5 sec before the specified time
+
 
                 if ( log )
                 fprintf ( log, "Setting RTC alarm to %d\n", alrt );
 
         tzset ( );
         
         alr = *gmtime ( &alrt );
 
         // get system time
         time ( &syst );
                 sys = *localtime ( &syst );     
                 
         // Write alarm time to RTC
         if (( fd = open ( "/dev/misc/rtc", O_RDWR )) < 0 )
                         error_msg_and_die ( 1, "/dev/misc/rtc" );
                 
         // get RTC time
         memset ( &rtc, 0, sizeof ( struct tm ));
         if ( ioctl ( fd, RTC_RD_TIME, &rtc ) < 0 )
                         error_msg_and_die ( 1, "ioctl RTC_RD_TIME" );   
         rtct = mktime ( &rtc );
 
         fprintf ( log, "System  time: %02d.%02d.%04d %02d:%02d:%02d DST: %d (TZ: %s, offset: %d)\n", sys. tm_mday, sys. tm_mon + 1, sys. tm_year + 1900, sys. tm_hour, sys. tm_min, sys. tm_sec, sys. tm_isdst, sys. tm_zone, sys. tm_gmtoff );
         fprintf ( log, "RTC     time: %02d.%02d.%04d %02d:%02d:%02d DST: %d (TZ: %s, offset: %d)\n", rtc. tm_mday, rtc. tm_mon + 1, rtc. tm_year + 1900, rtc. tm_hour, rtc. tm_min, rtc. tm_sec, rtc. tm_isdst, rtc. tm_zone, rtc. tm_gmtoff );
         fprintf ( log, "Wakeup  time: %02d.%02d.%04d %02d:%02d:%02d DST: %d (TZ: %s, offset: %d)\n", alr. tm_mday, alr. tm_mon + 1, alr. tm_year + 1900, alr. tm_hour, alr. tm_min, alr. tm_sec, alr. tm_isdst, alr. tm_zone, alr. tm_gmtoff );
 
         fprintf ( log, "System/RTC diff: %d seconds\n", (  syst - rtct ) - sys. tm_gmtoff );
 
 
         rtc_sys_diff = ( syst - rtct ) - sys. tm_gmtoff;
         
         if ( fix_rtc && (( rtc_sys_diff < -4 ) || ( rtc_sys_diff > 4 ))) {
                 struct tm set;
                 
                 set = *gmtime ( &syst );
         
                 fprintf ( log, "Correcting RTC: %d seconds\n", rtc_sys_diff );
 
             if ( ioctl ( fd, RTC_SET_TIME, &set ) < 0 )
                error_msg_and_die ( 1, "ioctl RTC_SET_TIME" );
         }
 
         // set alarm time
         if ( ioctl ( fd, RTC_ALM_SET, &alr ) < 0 )
                         error_msg_and_die ( 1, "ioctl RTC_ALM_SET" );   
                 // enable alarm irq
         if ( ioctl ( fd, RTC_AIE_ON, 0 ) < 0 )
                 error_msg_and_die ( 1, "ioctl RTC_AIE_ON" );
         
-        log_msg ( "SLEEPING\n" );
+        if ( log )
+                fprintf( log, "SIGUSR: pid %d - SLEEPING: pid %d\n", startpid, getpid ( ));
+        kill ( startpid, SIGUSR1 );
                         
         // wait for alarm irq
         if ( read ( fd, buf, sizeof( unsigned long )) < 0 )
                 error_msg_and_die ( 1, "read rtc alarm" );
         
         log_msg ( "WAKEUP\n" );
         
         // disable alarm irq
         if ( ioctl ( fd, RTC_AIE_OFF, 0 ) < 0 ) 
                 error_msg_and_die ( 1, "ioctl RTC_AIE_OFF" );
                 
         close ( fd );
         
         log_msg ( "EXITING\n" );
         
         fclose ( log );
         remove_pidfile ( );
         
         return 0;
 }
 
 
 int onac ( void )
 {
         FILE *fp;
         int on = 0;
 
         if (( fp = fopen ( APMFILE, "r" ))) { 
                 int ac = 0;
         
                 if ( fscanf ( fp, "%*[^ ] %*d.%*d 0x%*x 0x%x 0x%*x 0x%*x %*d%% %*i %*c", &ac ) == 1 )
                         on = ( ac == 0x01 ) ? 1 : 0;
 
                 fclose ( fp );
         }
         return on;
 }
 
 int resume ( int resuspend )
 {
         FILE *fp;
 
         // re-suspend when on AC (optional) when woken up via RTC
 
         if ( !opiealarm_was_running ) { // opiealarm -s got it's RTC signal -> wake up by RTC
                         if ( resuspend && onac ( )) {
                         time_t start, now;
                         char *argv [4];
                                                 
                         if ( !fork_with_pidfile ( ))
                                 return 4;
+                        kill ( startpid, SIGUSR1 );
 
                         // sleep <resuspend> sec (not less!)
                         time ( &start );
                         do {
                                 sleep ( 1 );
                                 time ( &now );
                         } while (( now - start ) < resuspend );
 
                         if ( onac ( )) { // still on ac
                                 // system() without fork
                                 argv[0] = "qcop";
                                 argv[1] = "QPE/Desktop";
                                 argv[2] = "suspend()";
                                 argv[3] = 0;
         
                                 // hard coded for now ...but needed
                                 setenv ( "LOGNAME", "root", 1 );
                                 setenv ( "HOME", "/root", 1 );
                                 setenv ( "LD_LIBRARY_PATH", "/opt/QtPalmtop/lib", 1 );
                                 setenv ( "QTDIR", "/opt/QtPalmtop", 1 );
                         
                                 remove_pidfile ( );
                         
                                 execv ( "/opt/QtPalmtop/bin/qcop", argv );
                                 
                                 perror ( "exec for qcop failed" );
                                 return 5;
                         }
                 }
         }
         return 0;
 }