Re: [PATCH 1/4] util: introduce shared daemon startup code

Several daemons have similar code around general daemon startup code. Let's move it into a file and share it among them. Signed-off-by: Rafael Fonseca <r4f4rfs(a)gmail.com&gt; --- src/libvirt_private.syms | 6 + src/util/Makefile.inc.am | 2 + src/util/virdaemon.c | 255 +++++++++++++++++++++++++++++++++++++++ src/util/virdaemon.h | 74 ++++++++++++ 4 files changed, 337 insertions(+) create mode 100644 src/util/virdaemon.c create mode 100644 src/util/virdaemon.h diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms index 3f032c7963..e276f55bb1 100644 --- a/src/libvirt_private.syms +++ b/src/libvirt_private.syms @@ -1906,6 +1906,12 @@ virCryptoHashString; virCryptoHaveCipher; +# util/virdaemon.h +virDaemonForkIntoBackground; +virDaemonSetupLogging; +virDaemonUnixSocketPaths; + + # util/virdbus.h virDBusCallMethod; virDBusCloseSystemBus; diff --git a/src/util/Makefile.inc.am b/src/util/Makefile.inc.am index 718b11a5f4..5bc60cb5ea 100644 --- a/src/util/Makefile.inc.am +++ b/src/util/Makefile.inc.am @@ -42,6 +42,8 @@ UTIL_SOURCES = \ util/virconf.h \ util/vircrypto.c \ util/vircrypto.h \ + util/virdaemon.c \ + util/virdaemon.h \ util/virdbus.c \ util/virdbus.h \ util/virdbuspriv.h \ diff --git a/src/util/virdaemon.c b/src/util/virdaemon.c new file mode 100644 index 0000000000..4b63b44d66 --- /dev/null +++ b/src/util/virdaemon.c @@ -0,0 +1,255 @@ +/* + * virdaemon.c: shared daemon setup code + * + * Copyright (C) 2020 Red Hat, Inc. + * + * This library is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; either + * version 2.1 of the License, or (at your option) any later version. + * + * This library 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 + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with this library; If not, see + * <http://www.gnu.org/licenses/>;. + */ + +#include <config.h> + +#include <sys/types.h> +#include <sys/stat.h> +#include <sys/wait.h> +#include <fcntl.h> +#include <unistd.h> +#include <stdbool.h> + +#include "virdaemon.h" +#include "virutil.h" +#include "virfile.h" +#include "virlog.h" +#include "viralloc.h" + +#include "configmake.h" + +int +virDaemonForkIntoBackground(const char *argv0) +{ + int statuspipe[2]; + if (virPipeQuiet(statuspipe) < 0) + return -1; + + pid_t pid = fork();

+ switch (pid) { + case 0: + { + /* intermediate child */ + int stdinfd = -1; + int stdoutfd = -1; + int nextpid; + + VIR_FORCE_CLOSE(statuspipe[0]); + + if ((stdinfd = open("/dev/null", O_RDONLY)) <= STDERR_FILENO) + goto cleanup; + if ((stdoutfd = open("/dev/null", O_WRONLY)) <= STDERR_FILENO)

+ goto cleanup; + if (dup2(stdinfd, STDIN_FILENO) != STDIN_FILENO) + goto cleanup; + if (dup2(stdoutfd, STDOUT_FILENO) != STDOUT_FILENO) + goto cleanup; + if (dup2(stdoutfd, STDERR_FILENO) != STDERR_FILENO) + goto cleanup; + if (VIR_CLOSE(stdinfd) < 0) + goto cleanup; + if (VIR_CLOSE(stdoutfd) < 0) + goto cleanup; + + if (setsid() < 0) + goto cleanup; + + nextpid = fork(); + switch (nextpid) { + case 0: /* grandchild */ + return statuspipe[1]; + case -1: /* error */ + goto cleanup; + default: /* intermediate child succeeded */ + _exit(EXIT_SUCCESS); + } + + cleanup: + VIR_FORCE_CLOSE(stdoutfd); + VIR_FORCE_CLOSE(stdinfd); + VIR_FORCE_CLOSE(statuspipe[1]); + _exit(EXIT_FAILURE); + + } + + case -1: /* error in parent */ + goto error; + + default: + { + /* parent */ + int got, exitstatus = 0; + int ret; + char status; + + VIR_FORCE_CLOSE(statuspipe[1]); + + /* We wait to make sure the first child forked successfully */ + if ((got = waitpid(pid, &exitstatus, 0)) < 0 || + got != pid || + exitstatus != 0) { + goto error; + } + + /* If we got here, then the grandchild was spawned, so we + * must exit. Block until the second child initializes + * successfully */ + again: + ret = read(statuspipe[0], &status, 1); + if (ret == -1 && errno == EINTR) + goto again;

+ + VIR_FORCE_CLOSE(statuspipe[0]); + + if (ret != 1) { + fprintf(stderr, + _("%s: error: unable to determine if daemon is " + "running: %s\n"), argv0, + g_strerror(errno)); + exit(EXIT_FAILURE); + } else if (status != 0) { + fprintf(stderr, + _("%s: error: %s. Check /var/log/messages or run without " + "--daemon for more info.\n"), argv0, + virDaemonErrTypeToString(status));

+ exit(EXIT_FAILURE); + } + _exit(EXIT_SUCCESS); + } + } + +error:

+ VIR_FORCE_CLOSE(statuspipe[0]); + VIR_FORCE_CLOSE(statuspipe[1]); + return -1; +} +