From 360ff12ea5b1e0dc3c83a373ddce20e109efaa9a Mon Sep 17 00:00:00 2001 From: Lennart Poettering Date: Sat, 4 Jun 2005 19:07:59 +0000 Subject: * implement proper PID file locking git-svn-id: file:///home/lennart/svn/public/libdaemon/trunk@79 153bfa13-eec0-0310-be40-b0cb6a0e1b4b --- configure.ac | 2 +- doc/README.html.in | 7 +++- doc/style.css | 16 ++----- libdaemon/Makefile.am | 2 +- libdaemon/dlog.c | 2 +- libdaemon/dlog.h | 2 +- libdaemon/dpid.c | 113 +++++++++++++++++++++++++++++++++++++------------- 7 files changed, 98 insertions(+), 46 deletions(-) diff --git a/configure.ac b/configure.ac index c89af5a..292a905 100644 --- a/configure.ac +++ b/configure.ac @@ -20,7 +20,7 @@ # Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA. AC_PREREQ(2.59) -AC_INIT([libdaemon],[0.7],[mzqnrzba (at) 0pointer (dot) de]) +AC_INIT([libdaemon],[0.8],[mzqnrzba (at) 0pointer (dot) de]) AC_CONFIG_SRCDIR([libdaemon/dfork.c]) AC_CONFIG_HEADERS([config.h]) AM_INIT_AUTOMAKE([foreign -Wall]) diff --git a/doc/README.html.in b/doc/README.html.in index fb6ebbc..755a39e 100644 --- a/doc/README.html.in +++ b/doc/README.html.in @@ -10,7 +10,7 @@

libdaemon @PACKAGE_VERSION@

License

News

Sat Jun 4 2005:

Version 0.8 released; changes include: proper PID file locking

Sat Dec 18 2004:

Version 0.7 released; changes include: minor cleanups; C++ compatibility; gcc 2.95 compatiblity

make install

If you want to be notified whenever I release a new version of this software use the subscription feature of Freshmeat.

Lennart Poettering <@PACKAGE_BUGREPORT@>, December 2004

Lennart Poettering <@PACKAGE_BUGREPORT@>, June 2005

$Id$

#include #include +#include +#include #include "dpid.h" #include "dlog.h" #define VARRUN "/var/run" -const char *daemon_pid_file_ident = 0; +const char *daemon_pid_file_ident = NULL; daemon_pid_file_proc_t daemon_pid_file_proc = daemon_pid_file_proc_default; const char *daemon_pid_file_proc_default(void) { @@ -47,41 +49,74 @@ const char *daemon_pid_file_proc_default(void) { return fn; } +static int lock_file(int fd, int enable) { + struct flock f; + + memset(&f, 0, sizeof(f)); + f.l_type = enable ? F_WRLCK : F_UNLCK; + f.l_whence = SEEK_SET; + f.l_start = 0; + f.l_len = 0; + + if (fcntl(fd, F_SETLKW, &f) < 0) { + daemon_log(LOG_WARNING, "fcntl(F_SETLKW) failed: %s", strerror(errno)); + return -1; + } + + return 0; +} + pid_t daemon_pid_file_is_running(void) { const char *fn; static char txt[256]; - FILE *f; - pid_t pid; - + int fd = -1, locked = -1; + pid_t ret = (pid_t) -1, pid; + ssize_t l; if (!(fn = daemon_pid_file_proc())) - return (pid_t) -1; + goto finish; - if (!(f = fopen(fn, "r"))) - return (pid_t) -1; + if ((fd = open(fn, O_RDWR, 0644)) < 0) { + if (errno != ENOENT) + daemon_log(LOG_WARNING, "Failed to open PID file: %s", strerror(errno)); - if (!(fgets(txt, sizeof(txt), f))) { - daemon_log(LOG_WARNING, "PID file corrupt, removing. (%s)", fn); - unlink(fn); - fclose(f); - return (pid_t) -1; + goto finish; } - fclose(f); + if ((locked = lock_file(fd, 1)) < 0) + goto finish; + + if ((l = read(fd, txt, sizeof(txt)-1)) < 0) { + daemon_log(LOG_WARNING, "read(): %s", strerror(errno)); + unlink(fn); + goto finish; + } + txt[l] = 0; + if ((pid = (pid_t) atoi(txt)) <= 0) { daemon_log(LOG_WARNING, "PID file corrupt, removing. (%s)", fn); unlink(fn); - return (pid_t) -1; + goto finish; } if (kill(pid, 0) != 0 && errno != EPERM) { - daemon_log(LOG_WARNING, "Daemon %u killed: %s; removing PID file. (%s)", pid, strerror(errno), fn); + daemon_log(LOG_WARNING, "Process %lu died: %s; removing PID file. (%s)", (unsigned long) pid, strerror(errno), fn); unlink(fn); - return (pid_t) -1; + goto finish; } + + ret = pid; - return pid; +finish: + + if (fd >= 0) { + if (locked >= 0) + lock_file(fd, 0); + close(fd); + } + + return ret; } int daemon_pid_file_kill(int s) { @@ -128,23 +163,45 @@ int daemon_pid_file_kill_wait(int s, int m) { int daemon_pid_file_create(void) { const char *fn; - FILE *f; - mode_t save; + int fd = -1; + int ret = -1; + int locked = -1; + char t[64]; + ssize_t l; if (!(fn = daemon_pid_file_proc())) - return -1; + goto finish; - save = umask(022); - - if (!(f = fopen(fn, "w"))) - return -1; + if ((fd = open(fn, O_CREAT|O_RDWR|O_EXCL, 0644)) < 0) { + fprintf(stderr, "open(%s): %s", fn, strerror(errno)); + goto finish; + } - fprintf(f, "%u\n", getpid()); - fclose(f); + if ((locked = lock_file(fd, 1)) < 0) { + unlink(fn); + goto finish; + } - umask(save); + snprintf(t, sizeof(t), "%lu\n", (unsigned long) getpid()); - return 0; + if (write(fd, t, l = strlen(t)) != l) { + daemon_log(LOG_WARNING, "write(): %s", strerror(errno)); + unlink(fn); + goto finish; + } + + ret = 0; + +finish: + + if (fd >= 0) { + if (locked >= 0) + lock_file(fd, 0); + + close(fd); + } + + return ret; } int daemon_pid_file_remove(void) { -- cgit