From 9565ab64e60f8282967e138f43c6057562dc5c27 Mon Sep 17 00:00:00 2001 From: zhanchengbin Date: Sat, 19 Nov 2022 11:50:07 -0500 Subject: [PATCH] nfs-blkmapd: PID file read by systemd failed When started nfs-blkmap.service, the PID file can't be opened, The cause is that the child process does not create the PID file before the systemd reads the PID file. Adding "ExecStartPost=/bin/sleep 0.1" to /usr/lib/systemd/system/nfs-blkmap.service will probably solve this problem, However, there is no guarantee that the above solutions are effective under high cpu pressure.So replace the daemon function with the fork function, and put the behavior of creating the PID file in the parent process to solve the above problems. Signed-off-by: zhanchengbin Signed-off-by: Zhiqiang Liu Signed-off-by: Steve Dickson --- utils/blkmapd/device-discovery.c | 48 ++++++++++++++++++++++++++-------------- 1 file changed, 32 insertions(+), 16 deletions(-) diff --git a/utils/blkmapd/device-discovery.c b/utils/blkmapd/device-discovery.c index bd89059..a565fdb 100644 --- a/utils/blkmapd/device-discovery.c +++ b/utils/blkmapd/device-discovery.c @@ -504,28 +504,44 @@ int main(int argc, char **argv) if (fg) { openlog("blkmapd", LOG_PERROR, 0); } else { - if (daemon(0, 0) != 0) { - fprintf(stderr, "Daemonize failed\n"); - exit(1); + pid_t pid = fork(); + if (pid < 0) { + BL_LOG_ERR("fork error\n"); + exit(1); + } else if (pid != 0) { + pidfd = open(PID_FILE, O_WRONLY | O_CREAT, 0644); + if (pidfd < 0) { + BL_LOG_ERR("Create pid file %s failed\n", PID_FILE); + exit(1); + } + + if (lockf(pidfd, F_TLOCK, 0) < 0) { + BL_LOG_ERR("Already running; Exiting!"); + close(pidfd); + exit(1); + } + if (ftruncate(pidfd, 0) < 0) + BL_LOG_ERR("ftruncate on %s failed: m\n", PID_FILE); + sprintf(pidbuf, "%d\n", pid); + if (write(pidfd, pidbuf, strlen(pidbuf)) != (ssize_t)strlen(pidbuf)) + BL_LOG_ERR("write on %s failed: m\n", PID_FILE); + exit(0); + } + + (void)setsid(); + if (chdir("/")) { + BL_LOG_ERR("chdir error\n"); + } + int fd = open("/dev/null", O_RDWR, 0); + if (fd >= 0) { + (void)dup2(fd, STDIN_FILENO); + (void)dup2(fd, STDOUT_FILENO); + (void)dup2(fd, STDERR_FILENO); + + (void)close(fd); } openlog("blkmapd", LOG_PID, 0); - pidfd = open(PID_FILE, O_WRONLY | O_CREAT, 0644); - if (pidfd < 0) { - BL_LOG_ERR("Create pid file %s failed\n", PID_FILE); - exit(1); - } - - if (lockf(pidfd, F_TLOCK, 0) < 0) { - BL_LOG_ERR("Already running; Exiting!"); - close(pidfd); - exit(1); - } - if (ftruncate(pidfd, 0) < 0) - BL_LOG_WARNING("ftruncate on %s failed: m\n", PID_FILE); - sprintf(pidbuf, "%d\n", getpid()); - if (write(pidfd, pidbuf, strlen(pidbuf)) != (ssize_t)strlen(pidbuf)) - BL_LOG_WARNING("write on %s failed: m\n", PID_FILE); } signal(SIGINT, sig_die); -- 2.27.0