diff --git a/include/qemu/osdep.h b/include/qemu/osdep.h index a746a5e531..4f8559e550 100644 --- a/include/qemu/osdep.h +++ b/include/qemu/osdep.h @@ -448,7 +448,8 @@ bool qemu_has_ofd_lock(void); #define FMT_pid "%d" #endif -int qemu_create_pidfile(const char *filename); +bool qemu_write_pidfile(const char *pidfile, Error **errp); + int qemu_get_thread_id(void); #ifndef CONFIG_IOVEC diff --git a/os-posix.c b/os-posix.c index 8f39447dd4..4bd80e44e6 100644 --- a/os-posix.c +++ b/os-posix.c @@ -344,30 +344,6 @@ void os_set_line_buffering(void) setvbuf(stdout, NULL, _IOLBF, 0); } -int qemu_create_pidfile(const char *filename) -{ - char buffer[128]; - int len; - int fd; - - fd = qemu_open(filename, O_RDWR | O_CREAT, 0600); - if (fd == -1) { - return -1; - } - if (lockf(fd, F_TLOCK, 0) == -1) { - close(fd); - return -1; - } - len = snprintf(buffer, sizeof(buffer), FMT_pid "\n", getpid()); - if (write(fd, buffer, len) != len) { - close(fd); - return -1; - } - - /* keep pidfile open & locked forever */ - return 0; -} - bool is_daemonized(void) { return daemonize; diff --git a/os-win32.c b/os-win32.c index 0674f94b57..0e0d7f50f3 100644 --- a/os-win32.c +++ b/os-win32.c @@ -97,28 +97,3 @@ int os_parse_cmd_args(int index, const char *optarg) { return -1; } - -int qemu_create_pidfile(const char *filename) -{ - char buffer[128]; - int len; - HANDLE file; - OVERLAPPED overlap; - BOOL ret; - memset(&overlap, 0, sizeof(overlap)); - - file = CreateFile(filename, GENERIC_WRITE, FILE_SHARE_READ, NULL, - OPEN_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL); - - if (file == INVALID_HANDLE_VALUE) { - return -1; - } - len = snprintf(buffer, sizeof(buffer), "%d\n", getpid()); - ret = WriteFile(file, (LPCVOID)buffer, (DWORD)len, - NULL, &overlap); - CloseHandle(file); - if (ret == 0) { - return -1; - } - return 0; -} diff --git a/qga/main.c b/qga/main.c index 6d70242d05..c399320d3c 100644 --- a/qga/main.c +++ b/qga/main.c @@ -340,46 +340,6 @@ static FILE *ga_open_logfile(const char *logfile) return f; } -#ifndef _WIN32 -static bool ga_open_pidfile(const char *pidfile) -{ - int pidfd; - char pidstr[32]; - - pidfd = qemu_open(pidfile, O_CREAT|O_WRONLY, S_IRUSR|S_IWUSR); - if (pidfd == -1 || lockf(pidfd, F_TLOCK, 0)) { - g_critical("Cannot lock pid file, %s", strerror(errno)); - if (pidfd != -1) { - close(pidfd); - } - return false; - } - - if (ftruncate(pidfd, 0)) { - g_critical("Failed to truncate pid file"); - goto fail; - } - snprintf(pidstr, sizeof(pidstr), "%d\n", getpid()); - if (write(pidfd, pidstr, strlen(pidstr)) != strlen(pidstr)) { - g_critical("Failed to write pid file"); - goto fail; - } - - /* keep pidfile open & locked forever */ - return true; - -fail: - unlink(pidfile); - close(pidfd); - return false; -} -#else /* _WIN32 */ -static bool ga_open_pidfile(const char *pidfile) -{ - return true; -} -#endif - static gint ga_strcmp(gconstpointer str1, gconstpointer str2) { return strcmp(str1, str2); @@ -479,8 +439,11 @@ void ga_unset_frozen(GAState *s) ga_enable_logging(s); g_warning("logging re-enabled due to filesystem unfreeze"); if (s->deferred_options.pid_filepath) { - if (!ga_open_pidfile(s->deferred_options.pid_filepath)) { - g_warning("failed to create/open pid file"); + Error *err = NULL; + + if (!qemu_write_pidfile(s->deferred_options.pid_filepath, &err)) { + g_warning("%s", error_get_pretty(err)); + error_free(err); } s->deferred_options.pid_filepath = NULL; } @@ -515,8 +478,11 @@ static void become_daemon(const char *pidfile) } if (pidfile) { - if (!ga_open_pidfile(pidfile)) { - g_critical("failed to create pidfile"); + Error *err = NULL; + + if (!qemu_write_pidfile(pidfile, &err)) { + g_critical("%s", error_get_pretty(err)); + error_free(err); exit(EXIT_FAILURE); } } diff --git a/scsi/qemu-pr-helper.c b/scsi/qemu-pr-helper.c index ed037aabee..ce40008bfc 100644 --- a/scsi/qemu-pr-helper.c +++ b/scsi/qemu-pr-helper.c @@ -117,39 +117,6 @@ QEMU_COPYRIGHT "\n" , name); } -static void write_pidfile(void) -{ - int pidfd; - char pidstr[32]; - - pidfd = qemu_open(pidfile, O_CREAT|O_WRONLY, S_IRUSR|S_IWUSR); - if (pidfd == -1) { - error_report("Cannot open pid file, %s", strerror(errno)); - exit(EXIT_FAILURE); - } - - if (lockf(pidfd, F_TLOCK, 0)) { - error_report("Cannot lock pid file, %s", strerror(errno)); - goto fail; - } - if (ftruncate(pidfd, 0)) { - error_report("Failed to truncate pid file"); - goto fail; - } - - snprintf(pidstr, sizeof(pidstr), "%d\n", getpid()); - if (write(pidfd, pidstr, strlen(pidstr)) != strlen(pidstr)) { - error_report("Failed to write pid file"); - goto fail; - } - return; - -fail: - unlink(pidfile); - close(pidfd); - exit(EXIT_FAILURE); -} - /* SG_IO support */ typedef struct PRHelperSGIOData { @@ -1080,8 +1047,11 @@ int main(int argc, char **argv) } } - if (daemonize || pidfile_specified) - write_pidfile(); + if ((daemonize || pidfile_specified) && + !qemu_write_pidfile(pidfile, &local_err)) { + error_report_err(local_err); + exit(EXIT_FAILURE); + } #ifdef CONFIG_LIBCAP if (drop_privileges() < 0) { diff --git a/util/oslib-posix.c b/util/oslib-posix.c index 13b6f8d776..0e3ab9d959 100644 --- a/util/oslib-posix.c +++ b/util/oslib-posix.c @@ -88,6 +88,74 @@ int qemu_daemon(int nochdir, int noclose) return daemon(nochdir, noclose); } +bool qemu_write_pidfile(const char *path, Error **errp) +{ + int fd; + char pidstr[32]; + + while (1) { + struct stat a, b; + + fd = qemu_open(path, O_CREAT | O_WRONLY, S_IRUSR | S_IWUSR); + if (fd == -1) { + error_setg_errno(errp, errno, "Cannot open pid file"); + return false; + } + + if (fstat(fd, &b) < 0) { + error_setg_errno(errp, errno, "Cannot stat file"); + goto fail_close; + } + + if (lockf(fd, F_TLOCK, 0) < 0) { + error_setg_errno(errp, errno, "Cannot lock pid file"); + goto fail_close; + } + + /* + * Now make sure the path we locked is the same one that now + * exists on the filesystem. + */ + if (stat(path, &a) < 0) { + /* + * PID file disappeared, someone else must be racing with + * us, so try again. + */ + close(fd); + continue; + } + + if (a.st_ino == b.st_ino) { + break; + } + + /* + * PID file was recreated, someone else must be racing with + * us, so try again. + */ + close(fd); + } + + if (ftruncate(fd, 0) < 0) { + error_setg_errno(errp, errno, "Failed to truncate pid file"); + goto fail_unlink; + } + + snprintf(pidstr, sizeof(pidstr), FMT_pid "\n", getpid()); + if (write(fd, pidstr, strlen(pidstr)) != strlen(pidstr)) { + error_setg(errp, "Failed to write pid file"); + goto fail_unlink; + } + + return true; + +fail_unlink: + unlink(path); +fail_close: + close(fd); + return false; +} + void *qemu_oom_check(void *ptr) { if (ptr == NULL) { diff --git a/util/oslib-win32.c b/util/oslib-win32.c index 25dd1595ad..b4c17f5dfa 100644 --- a/util/oslib-win32.c +++ b/util/oslib-win32.c @@ -776,3 +776,30 @@ ssize_t qemu_recvfrom_wrap(int sockfd, void *buf, size_t len, int flags, } return ret; } + +bool qemu_write_pidfile(const char *filename, Error **errp) +{ + char buffer[128]; + int len; + HANDLE file; + OVERLAPPED overlap; + BOOL ret; + memset(&overlap, 0, sizeof(overlap)); + + file = CreateFile(filename, GENERIC_WRITE, FILE_SHARE_READ, NULL, + OPEN_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL); + + if (file == INVALID_HANDLE_VALUE) { + error_setg(errp, "Failed to create PID file"); + return false; + } + len = snprintf(buffer, sizeof(buffer), FMT_pid "\n", (pid_t)getpid()); + ret = WriteFile(file, (LPCVOID)buffer, (DWORD)len, + NULL, &overlap); + CloseHandle(file); + if (ret == 0) { + error_setg(errp, "Failed to write PID file"); + return false; + } + return true; +} diff --git a/vl.c b/vl.c index cc55fe04a2..fa6db178a6 100644 --- a/vl.c +++ b/vl.c @@ -3906,8 +3906,8 @@ int main(int argc, char **argv, char **envp) os_daemonize(); rcu_disable_atfork(); - if (pid_file && qemu_create_pidfile(pid_file) != 0) { - error_report("could not acquire pid file: %s", strerror(errno)); + if (pid_file && !qemu_write_pidfile(pid_file, &err)) { + error_reportf_err(err, "cannot create PID file: "); exit(1); }