src/lib/daemon.c
/*
* Author: Yasuhito Takamiya <yasuhito@gmail.com>
*
* Copyright (C) 2008-2013 NEC Corporation
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License, version 2, as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include <assert.h>
#include <errno.h>
#include <fcntl.h>
#include <limits.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <unistd.h>
#include "checks.h"
#include "log.h"
#include "wrapper.h"
#ifdef UNIT_TESTING
#ifdef die
#undef die
#endif
#define die mock_die
void mock_die( const char *format, ... );
#ifdef chdir
#undef chdir
#endif // chdir
#define chdir mock_chdir
extern int mock_chdir( const char *path );
#ifdef fork
#undef fork
#endif // fork
#define fork mock_fork
extern pid_t mock_fork( void );
#ifdef exit
#undef exit
#endif // exit
#define exit mock_exit
extern void mock_exit( int status );
#ifdef setsid
#undef setsid
#endif // setsid
#define setsid mock_setsid
extern pid_t mock_setsid( void );
#ifdef umask
#undef umask
#endif // umask
#define umask mock_umask
extern mode_t mock_umask( mode_t mask );
#ifdef open
#undef open
#endif // open
#define open mock_open
extern int mock_open( const char *pathname, int flags, mode_t mode );
#ifdef close
#undef close
#endif // close
#define close mock_close
extern int mock_close( int fd );
#ifdef lockf
#undef lockf
#endif // lockf
#define lockf mock_lockf
extern int mock_lockf( int fd, int cmd, off_t len );
#ifdef getpid
#undef getpid
#endif // getpid
#define getpid mock_getpid
extern pid_t mock_getpid( void );
#ifdef write
#undef write
#endif // write
#define write mock_write
extern ssize_t mock_write( int fd, const void *buf, size_t count );
#ifdef unlink
#undef unlink
#endif // unlink
#define unlink mock_unlink
extern int mock_unlink( const char *pathname );
#ifdef access
#undef access
#endif // access
#define access mock_access
extern int mock_access( const char *pathname, int mode );
#ifdef read
#undef read
#endif // read
#define read mock_read
extern ssize_t mock_read( int fd, void *buf, size_t count );
#ifdef kill
#undef kill
#endif // kill
#define kill mock_kill
extern int mock_kill( pid_t pid, int sig );
#ifdef rename
#undef rename
#endif // rename
#define rename mock_rename
extern int mock_rename( const char *oldpath, const char *newpath );
#ifdef warn
#undef warn
#endif // warn
#define warn mock_warn
extern void mock_warn( const char *format, ... );
#endif // UNIT_TESTING
void
daemonize( const char *home ) {
assert( home != NULL );
char buf[ 256 ];
if ( chdir( home ) < 0 ) {
die( "Could not cd to %s: %s.", home, strerror_r( errno, buf, sizeof( buf ) ) );
}
pid_t pid = fork();
if ( pid < 0 ) {
die( "fork() failed: %s.", strerror_r( errno, buf, sizeof( buf ) ) );
}
if ( pid > 0 ) {
exit( EXIT_SUCCESS );
}
pid_t sid = setsid();
if ( sid < 0 ) {
die( "setsid() failed: %s.", strerror_r( errno, buf, sizeof( buf ) ) );
}
umask( 0 );
close( STDIN_FILENO );
close( STDOUT_FILENO );
close( STDERR_FILENO );
}
static const int PID_STRING_LENGTH = 10;
void
write_pid( const char *directory, const char *name ) {
assert( directory != NULL );
assert( name != NULL );
char path[ PATH_MAX ];
snprintf( path, PATH_MAX, "%s/%s.pid", directory, name );
path[ PATH_MAX - 1 ] = '\0';
int fd = open( path, O_RDWR | O_CREAT, 0600 );
if ( fd == -1 ) {
die( "Could not create a PID file: %s", path );
}
if ( lockf( fd, F_TLOCK, 0 ) == -1 ) {
die( "Could not acquire a lock on a PID file: %s", path );
}
char str[ PID_STRING_LENGTH ];
snprintf( str, sizeof( str ),"%d\n", getpid() );
str[ sizeof( str ) - 1 ] = '\0';
ssize_t ret = write( fd, str, strlen( str ) );
close( fd );
if ( ret == -1 ) {
die( "Could not write a PID file: %s", path );
}
}
void
unlink_pid( const char *directory, const char *name ) {
assert( directory != NULL );
assert( name != NULL );
char path[ PATH_MAX ];
snprintf( path, PATH_MAX, "%s/%s.pid", directory, name );
path[ PATH_MAX - 1 ] = '\0';
int ret = unlink( path );
if ( ret < 0 ) {
die( "Could not remove a PID file: %s", path );
}
}
pid_t
read_pid( const char *directory, const char *name ) {
assert( directory != NULL );
assert( name != NULL );
char path[ PATH_MAX ];
snprintf( path, PATH_MAX, "%s/%s.pid", directory, name );
path[ PATH_MAX - 1 ] = '\0';
if ( access( path, R_OK ) < 0 ) {
return -1;
}
int fd = open( path, O_RDONLY, 0 );
if ( fd < 0 ) {
warn( "Failed to open %s ( %s [%d] ).", path, strerror( errno ), errno );
return -1;
}
char str[ PID_STRING_LENGTH ];
ssize_t length = read( fd, str, sizeof( str ) - 1 );
if ( length < 0 ) {
warn( "Failed to read pid from %s ( %s [%d] ).", path, strerror( errno ), errno );
close( fd );
return -1;
}
str[ length ] = '\0';
if ( str[ length - 1 ] == '\n' ) {
str[ length - 1 ] = '\0';
}
close( fd );
char *endp = NULL;
pid_t pid = ( pid_t ) strtol( str, &endp, 0 );
if ( *endp != '\0' ) {
warn( "Invalid pid `%s'.", str );
return -1;
}
if ( pid <= 0 ) {
warn( "Invalid pid %d.", pid );
return -1;
}
int ret = kill( pid, 0 );
if ( ret < 0 ) {
warn( "Failed to check process id %d ( %s [%d] ).", pid, strerror( errno ), errno );
if ( errno == ESRCH ) {
unlink( path );
}
return -1;
}
return pid;
}
void
rename_pid( const char *directory, const char *old, const char *new ) {
assert( directory != NULL );
assert( old != NULL );
assert( new != NULL );
char old_path[ PATH_MAX ];
snprintf( old_path, PATH_MAX, "%s/%s.pid", directory, old );
old_path[ PATH_MAX - 1 ] = '\0';
char new_path[ PATH_MAX ];
snprintf( new_path, PATH_MAX, "%s/%s.pid", directory, new );
new_path[ PATH_MAX - 1 ] = '\0';
unlink( new_path );
int ret = rename( old_path, new_path );
if ( ret < 0 ) {
die( "Could not rename a PID file from %s to %s.", old_path, new_path );
}
}
/*
* Local variables:
* c-basic-offset: 2
* indent-tabs-mode: nil
* End:
*/