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761bbb17c7
libvirt/src/util/command.c
Eric Blake 761bbb17c7 build: add syntax check for proper flags use 
Enforce the recent flags cleanups - we want to use 'unsigned int flags'
in any of our APIs (except where backwards compatibility is important,
in the public migration APIs), and that all flags are checked for
validity (except when there are stub functions that completely
ignore the flags argument).

There are a few minor tweaks done here to avoid false positives:
signed arguments passed to open() are renamed oflags, and flags
arguments that are legitimately ignored are renamed flags_unused.

* cfg.mk (sc_flags_usage): New rule.
(exclude_file_name_regexp--sc_flags_usage): And a few exemptions.
(sc_flags_debug): Tweak wording.
* src/util/iohelper.c (runIO, main): Rename variable.
* src/util/util.c (virSetInherit): Likewise.
* src/fdstream.h (virFDStreamOpenFile, virFDStreamCreateFile):
Likewise.
* src/fdstream.c (virFDStreamOpenFileInternal)
(virFDStreamOpenFile, virFDStreamCreateFile): Likewise.
* src/util/command.c (virExecWithHook) [WIN32]: Likewise.
* src/util/util.c (virFileOpenAs, virDirCreate) [WIN32]: Likewise.
* src/locking/lock_manager.c (virLockManagerPluginNew)
[!HAVE_DLFCN_H]: Likewise.
* src/locking/lock_driver_nop.c (virLockManagerNopNew)
(virLockManagerNopAddResource, virLockManagerNopAcquire)
(virLockManagerNopRelease, virLockManagerNopInquire): Likewise.
2011-07-15 16:37:30 -06:00

2259 lines
60 KiB
C
Raw Blame History

/*
* command.c: Child command execution
*
* Copyright (C) 2010-2011 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, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
*/
#include <config.h>
#include <poll.h>
#include <signal.h>
#include <stdarg.h>
#include <stdlib.h>
#include <sys/stat.h>
#include <sys/wait.h>
#include <fcntl.h>
#if HAVE_CAPNG
# include <cap-ng.h>
#endif
#include "command.h"
#include "memory.h"
#include "virterror_internal.h"
#include "util.h"
#include "logging.h"
#include "files.h"
#include "buf.h"
#include "ignore-value.h"
#include "verify.h"
#define VIR_FROM_THIS VIR_FROM_NONE
#define virCommandError(code, ...) \
virReportErrorHelper(VIR_FROM_NONE, code, __FILE__, \
__FUNCTION__, __LINE__, __VA_ARGS__)
/* We have quite a bit of changes to make if this doesn't hold. */
verify(sizeof(pid_t) <= sizeof(int));
/* Flags for virExecWithHook */
enum {
VIR_EXEC_NONE = 0,
VIR_EXEC_NONBLOCK = (1 << 0),
VIR_EXEC_DAEMON = (1 << 1),
VIR_EXEC_CLEAR_CAPS = (1 << 2),
VIR_EXEC_RUN_SYNC = (1 << 3),
};
struct _virCommand {
int has_error; /* ENOMEM on allocation failure, -1 for anything else. */
char **args;
size_t nargs;
size_t maxargs;
char **env;
size_t nenv;
size_t maxenv;
char *pwd;
/* XXX Use int[] if we ever need to support more than FD_SETSIZE fd's. */
fd_set preserve; /* FDs to pass to child. */
fd_set transfer; /* FDs to close in parent. */
unsigned int flags;
char *inbuf;
char **outbuf;
char **errbuf;
int infd;
int inpipe;
int outfd;
int errfd;
int *outfdptr;
int *errfdptr;
bool handshake;
int handshakeWait[2];
int handshakeNotify[2];
virExecHook hook;
void *opaque;
pid_t pid;
char *pidfile;
bool reap;
};
#ifndef WIN32
# if HAVE_CAPNG
static int virClearCapabilities(void)
{
int ret;
capng_clear(CAPNG_SELECT_BOTH);
if ((ret = capng_apply(CAPNG_SELECT_BOTH)) < 0) {
virCommandError(VIR_ERR_INTERNAL_ERROR,
_("cannot clear process capabilities %d"), ret);
return -1;
}
return 0;
}
# else
static int virClearCapabilities(void)
{
// VIR_WARN("libcap-ng support not compiled in, unable to clear "
// "capabilities");
return 0;
}
# endif
/* virFork() - fork a new process while avoiding various race/deadlock
conditions
@pid - a pointer to a pid_t that will receive the return value from
fork()
on return from virFork(), if *pid < 0, the fork failed and there is
no new process. Otherwise, just like fork(), if *pid == 0, it is the
child process returning, and if *pid > 0, it is the parent.
Even if *pid >= 0, if the return value from virFork() is < 0, it
indicates a failure that occurred in the parent or child process
after the fork. In this case, the child process should call
_exit(EXIT_FAILURE) after doing any additional error reporting.
*/
int virFork(pid_t *pid) {
sigset_t oldmask, newmask;
struct sigaction sig_action;
int saved_errno, ret = -1;
*pid = -1;
/*
* Need to block signals now, so that child process can safely
* kill off caller's signal handlers without a race.
*/
sigfillset(&newmask);
if (pthread_sigmask(SIG_SETMASK, &newmask, &oldmask) != 0) {
saved_errno = errno;
virReportSystemError(errno,
"%s", _("cannot block signals"));
goto cleanup;
}
/* Ensure we hold the logging lock, to protect child processes
* from deadlocking on another thread's inherited mutex state */
virLogLock();
*pid = fork();
saved_errno = errno; /* save for caller */
/* Unlock for both parent and child process */
virLogUnlock();
if (*pid < 0) {
/* attempt to restore signal mask, but ignore failure, to
avoid obscuring the fork failure */
ignore_value (pthread_sigmask(SIG_SETMASK, &oldmask, NULL));
virReportSystemError(saved_errno,
"%s", _("cannot fork child process"));
goto cleanup;
}
if (*pid) {
/* parent process */
/* Restore our original signal mask now that the child is
safely running */
if (pthread_sigmask(SIG_SETMASK, &oldmask, NULL) != 0) {
saved_errno = errno; /* save for caller */
virReportSystemError(errno, "%s", _("cannot unblock signals"));
goto cleanup;
}
ret = 0;
} else {
/* child process */
int logprio;
int i;
/* Remove any error callback so errors in child now
get sent to stderr where they stand a fighting chance
of being seen / logged */
virSetErrorFunc(NULL, NULL);
virSetErrorLogPriorityFunc(NULL);
/* Make sure any hook logging is sent to stderr, since child
* process may close the logfile FDs */
logprio = virLogGetDefaultPriority();
virLogReset();
virLogSetDefaultPriority(logprio);
/* Clear out all signal handlers from parent so nothing
unexpected can happen in our child once we unblock
signals */
sig_action.sa_handler = SIG_DFL;
sig_action.sa_flags = 0;
sigemptyset(&sig_action.sa_mask);
for (i = 1; i < NSIG; i++) {
/* Only possible errors are EFAULT or EINVAL
The former wont happen, the latter we
expect, so no need to check return value */
sigaction(i, &sig_action, NULL);
}
/* Unmask all signals in child, since we've no idea
what the caller's done with their signal mask
and don't want to propagate that to children */
sigemptyset(&newmask);
if (pthread_sigmask(SIG_SETMASK, &newmask, NULL) != 0) {
saved_errno = errno; /* save for caller */
virReportSystemError(errno, "%s", _("cannot unblock signals"));
goto cleanup;
}
ret = 0;
}
cleanup:
if (ret < 0)
errno = saved_errno;
return ret;
}
/*
* Ensure that *null is an fd visiting /dev/null. Return 0 on
* success, -1 on failure. Allows for lazy opening of shared
* /dev/null fd only as required.
*/
static int
getDevNull(int *null)
{
if (*null == -1 && (*null = open("/dev/null", O_RDWR)) < 0) {
virReportSystemError(errno,
_("cannot open %s"),
"/dev/null");
return -1;
}
return 0;
}
/*
* @argv argv to exec
* @envp optional environment to use for exec
* @keepfd options fd_ret to keep open for child process
* @retpid optional pointer to store child process pid
* @infd optional file descriptor to use as child input, otherwise /dev/null
* @outfd optional pointer to communicate output fd behavior
* outfd == NULL : Use /dev/null
* *outfd == -1 : Use a new fd
* *outfd != -1 : Use *outfd
* @errfd optional pointer to communcate error fd behavior. See outfd
* @flags possible combination of the following:
* VIR_EXEC_NONE : Default function behavior
* VIR_EXEC_NONBLOCK : Set child process output fd's as non-blocking
* VIR_EXEC_DAEMON : Daemonize the child process
* @hook optional virExecHook function to call prior to exec
* @data data to pass to the hook function
* @pidfile path to use as pidfile for daemonized process (needs DAEMON flag)
*/
static int
virExecWithHook(const char *const*argv,
const char *const*envp,
const fd_set *keepfd,
pid_t *retpid,
int infd, int *outfd, int *errfd,
unsigned int flags,
virExecHook hook,
void *data,
char *pidfile)
{
pid_t pid;
int null = -1, i, openmax;
int pipeout[2] = {-1,-1};
int pipeerr[2] = {-1,-1};
int childout = -1;
int childerr = -1;
int tmpfd;
const char *binary = NULL;
int forkRet;
if (argv[0][0] != '/') {
if (!(binary = virFindFileInPath(argv[0]))) {
virReportSystemError(ENOENT,
_("Cannot find '%s' in path"),
argv[0]);
return -1;
}
} else {
binary = argv[0];
}
if (infd < 0) {
if (getDevNull(&null) < 0)
goto cleanup;
infd = null;
}
if (outfd != NULL) {
if (*outfd == -1) {
if (pipe(pipeout) < 0) {
virReportSystemError(errno,
"%s", _("cannot create pipe"));
goto cleanup;
}
if ((flags & VIR_EXEC_NONBLOCK) &&
virSetNonBlock(pipeout[0]) == -1) {
virReportSystemError(errno,
"%s", _("Failed to set non-blocking file descriptor flag"));
goto cleanup;
}
if (virSetCloseExec(pipeout[0]) == -1) {
virReportSystemError(errno,
"%s", _("Failed to set close-on-exec file descriptor flag"));
goto cleanup;
}
childout = pipeout[1];
} else {
childout = *outfd;
}
} else {
if (getDevNull(&null) < 0)
goto cleanup;
childout = null;
}
if (errfd != NULL) {
if (*errfd == -1) {
if (pipe(pipeerr) < 0) {
virReportSystemError(errno,
"%s", _("Failed to create pipe"));
goto cleanup;
}
if ((flags & VIR_EXEC_NONBLOCK) &&
virSetNonBlock(pipeerr[0]) == -1) {
virReportSystemError(errno,
"%s", _("Failed to set non-blocking file descriptor flag"));
goto cleanup;
}
if (virSetCloseExec(pipeerr[0]) == -1) {
virReportSystemError(errno,
"%s", _("Failed to set close-on-exec file descriptor flag"));
goto cleanup;
}
childerr = pipeerr[1];
} else {
childerr = *errfd;
}
} else {
if (getDevNull(&null) < 0)
goto cleanup;
childerr = null;
}
forkRet = virFork(&pid);
if (pid < 0) {
goto cleanup;
}
if (pid) { /* parent */
VIR_FORCE_CLOSE(null);
if (outfd && *outfd == -1) {
VIR_FORCE_CLOSE(pipeout[1]);
*outfd = pipeout[0];
}
if (errfd && *errfd == -1) {
VIR_FORCE_CLOSE(pipeerr[1]);
*errfd = pipeerr[0];
}
if (forkRet < 0) {
goto cleanup;
}
*retpid = pid;
if (binary != argv[0])
VIR_FREE(binary);
return 0;
}
/* child */
if (forkRet < 0) {
/* The fork was successful, but after that there was an error
* in the child (which was already logged).
*/
goto fork_error;
}
openmax = sysconf(_SC_OPEN_MAX);
for (i = 3; i < openmax; i++)
if (i != infd &&
i != childout &&
i != childerr &&
(!keepfd || i >= FD_SETSIZE || !FD_ISSET(i, keepfd))) {
tmpfd = i;
VIR_FORCE_CLOSE(tmpfd);
}
if (dup2(infd, STDIN_FILENO) < 0) {
virReportSystemError(errno,
"%s", _("failed to setup stdin file handle"));
goto fork_error;
}
if (childout > 0 &&
dup2(childout, STDOUT_FILENO) < 0) {
virReportSystemError(errno,
"%s", _("failed to setup stdout file handle"));
goto fork_error;
}
if (childerr > 0 &&
dup2(childerr, STDERR_FILENO) < 0) {
virReportSystemError(errno,
"%s", _("failed to setup stderr file handle"));
goto fork_error;
}
if (infd != STDIN_FILENO && infd != null)
VIR_FORCE_CLOSE(infd);
if (childout > STDERR_FILENO && childout != null) {
tmpfd = childout; /* preserve childout value */
VIR_FORCE_CLOSE(tmpfd);
}
if (childerr > STDERR_FILENO &&
childerr != childout &&
childerr != null) {
VIR_FORCE_CLOSE(childerr);
}
VIR_FORCE_CLOSE(null);
/* Initialize full logging for a while */
virLogSetFromEnv();
/* Daemonize as late as possible, so the parent process can detect
* the above errors with wait* */
if (flags & VIR_EXEC_DAEMON) {
if (setsid() < 0) {
virReportSystemError(errno,
"%s", _("cannot become session leader"));
goto fork_error;
}
if (chdir("/") < 0) {
virReportSystemError(errno,
"%s", _("cannot change to root directory"));
goto fork_error;
}
pid = fork();
if (pid < 0) {
virReportSystemError(errno,
"%s", _("cannot fork child process"));
goto fork_error;
}
if (pid > 0) {
if (pidfile && virFileWritePidPath(pidfile,pid)) {
kill(pid, SIGTERM);
usleep(500*1000);
kill(pid, SIGTERM);
virReportSystemError(errno,
_("could not write pidfile %s for %d"),
pidfile, pid);
goto fork_error;
}
_exit(0);
}
}
if (hook) {
/* virFork reset all signal handlers to the defaults.
* This is good for the child process, but our hook
* risks running something that generates SIGPIPE,
* so we need to temporarily block that again
*/
struct sigaction waxon, waxoff;
memset(&waxoff, 0, sizeof(waxoff));
waxoff.sa_handler = SIG_IGN;
sigemptyset(&waxoff.sa_mask);
memset(&waxon, 0, sizeof(waxon));
if (sigaction(SIGPIPE, &waxoff, &waxon) < 0) {
virReportSystemError(errno, "%s",
_("Could not disable SIGPIPE"));
goto fork_error;
}
if ((hook)(data) != 0) {
VIR_DEBUG("Hook function failed.");
goto fork_error;
}
if (sigaction(SIGPIPE, &waxon, NULL) < 0) {
virReportSystemError(errno, "%s",
_("Could not re-enable SIGPIPE"));
goto fork_error;
}
}
/* The steps above may need todo something privileged, so
* we delay clearing capabilities until the last minute */
if ((flags & VIR_EXEC_CLEAR_CAPS) &&
virClearCapabilities() < 0)
goto fork_error;
/* Close logging again to ensure no FDs leak to child */
virLogReset();
if (envp)
execve(binary, (char **) argv, (char**)envp);
else
execv(binary, (char **) argv);
virReportSystemError(errno,
_("cannot execute binary %s"),
argv[0]);
fork_error:
virDispatchError(NULL);
_exit(EXIT_FAILURE);
cleanup:
/* This is cleanup of parent process only - child
should never jump here on error */
if (binary != argv[0])
VIR_FREE(binary);
/* NB we don't virCommandError() on any failures here
because the code which jumped hre already raised
an error condition which we must not overwrite */
VIR_FORCE_CLOSE(pipeerr[0]);
VIR_FORCE_CLOSE(pipeerr[1]);
VIR_FORCE_CLOSE(pipeout[0]);
VIR_FORCE_CLOSE(pipeout[1]);
VIR_FORCE_CLOSE(null);
return -1;
}
/**
* @argv NULL terminated argv to run
* @status optional variable to return exit status in
*
* Run a command without using the shell.
*
* If status is NULL, then return 0 if the command run and
* exited with 0 status; Otherwise return -1
*
* If status is not-NULL, then return 0 if the command ran.
* The status variable is filled with the command exit status
* and should be checked by caller for success. Return -1
* only if the command could not be run.
*/
int
virRun(const char *const*argv, int *status)
{
int ret;
virCommandPtr cmd = virCommandNewArgs(argv);
ret = virCommandRun(cmd, status);
virCommandFree(cmd);
return ret;
}
#else /* WIN32 */
int
virRun(const char *const *argv ATTRIBUTE_UNUSED,
int *status)
{
if (status)
*status = ENOTSUP;
else
virCommandError(VIR_ERR_INTERNAL_ERROR,
"%s", _("virRun is not implemented for WIN32"));
return -1;
}
static int
virExecWithHook(const char *const*argv ATTRIBUTE_UNUSED,
const char *const*envp ATTRIBUTE_UNUSED,
const fd_set *keepfd ATTRIBUTE_UNUSED,
pid_t *retpid ATTRIBUTE_UNUSED,
int infd ATTRIBUTE_UNUSED,
int *outfd ATTRIBUTE_UNUSED,
int *errfd ATTRIBUTE_UNUSED,
int flags_unused ATTRIBUTE_UNUSED,
virExecHook hook ATTRIBUTE_UNUSED,
void *data ATTRIBUTE_UNUSED,
char *pidfile ATTRIBUTE_UNUSED)
{
/* XXX: Some day we can implement pieces of virCommand/virExec on
* top of _spawn() or CreateProcess(), but we can't implement
* everything, since mingw completely lacks fork(), so we cannot
* run hook code in the child. */
virCommandError(VIR_ERR_INTERNAL_ERROR,
"%s", _("virExec is not implemented for WIN32"));
return -1;
}
int
virFork(pid_t *pid)
{
*pid = -1;
errno = ENOTSUP;
return -1;
}
#endif /* WIN32 */
/*
* Create a new command for named binary
*/
virCommandPtr
virCommandNew(const char *binary)
{
const char *const args[] = { binary, NULL };
return virCommandNewArgs(args);
}
/*
* Create a new command with a NULL terminated
* set of args, taking binary from args[0]
*/
virCommandPtr
virCommandNewArgs(const char *const*args)
{
virCommandPtr cmd;
if (VIR_ALLOC(cmd) < 0)
return NULL;
cmd->handshakeWait[0] = -1;
cmd->handshakeWait[1] = -1;
cmd->handshakeNotify[0] = -1;
cmd->handshakeNotify[1] = -1;
FD_ZERO(&cmd->preserve);
FD_ZERO(&cmd->transfer);
cmd->infd = cmd->outfd = cmd->errfd = -1;
cmd->inpipe = -1;
cmd->pid = -1;
virCommandAddArgSet(cmd, args);
return cmd;
}
/*
* Create a new command with a NULL terminated
* list of args, starting with the binary to run
*/
virCommandPtr
virCommandNewArgList(const char *binary, ...)
{
virCommandPtr cmd = virCommandNew(binary);
va_list list;
const char *arg;
if (!cmd || cmd->has_error)
return cmd;
va_start(list, binary);
while ((arg = va_arg(list, const char *)) != NULL)
virCommandAddArg(cmd, arg);
va_end(list);
return cmd;
}
/*
* Preserve the specified file descriptor in the child, instead of
* closing it. FD must not be one of the three standard streams. If
* transfer is true, then fd will be closed in the parent after a call
* to Run/RunAsync/Free, otherwise caller is still responsible for fd.
*/
static void
virCommandKeepFD(virCommandPtr cmd, int fd, bool transfer)
{
if (!cmd)
return;
if (fd <= STDERR_FILENO || FD_SETSIZE <= fd) {
if (!cmd->has_error)
cmd->has_error = -1;
VIR_DEBUG("cannot preserve %d", fd);
return;
}
FD_SET(fd, &cmd->preserve);
if (transfer)
FD_SET(fd, &cmd->transfer);
}
/*
* Preserve the specified file descriptor
* in the child, instead of closing it.
* The parent is still responsible for managing fd.
*/
void
virCommandPreserveFD(virCommandPtr cmd, int fd)
{
return virCommandKeepFD(cmd, fd, false);
}
/*
* Transfer the specified file descriptor
* to the child, instead of closing it.
* Close the fd in the parent during Run/RunAsync/Free.
*/
void
virCommandTransferFD(virCommandPtr cmd, int fd)
{
return virCommandKeepFD(cmd, fd, true);
}
/*
* Save the child PID in a pidfile
*/
void
virCommandSetPidFile(virCommandPtr cmd, const char *pidfile)
{
if (!cmd || cmd->has_error)
return;
VIR_FREE(cmd->pidfile);
if (!(cmd->pidfile = strdup(pidfile))) {
cmd->has_error = ENOMEM;
}
}
/*
* Remove all capabilities from the child
*/
void
virCommandClearCaps(virCommandPtr cmd)
{
if (!cmd || cmd->has_error)
return;
cmd->flags |= VIR_EXEC_CLEAR_CAPS;
}
#if 0 /* XXX Enable if we have a need for capability management. */
/*
* Re-allow a specific capability
*/
void
virCommandAllowCap(virCommandPtr cmd,
int capability ATTRIBUTE_UNUSED)
{
if (!cmd || cmd->has_error)
return;
/* XXX ? */
}
#endif /* 0 */
/*
* Daemonize the child process
*/
void
virCommandDaemonize(virCommandPtr cmd)
{
if (!cmd || cmd->has_error)
return;
cmd->flags |= VIR_EXEC_DAEMON;
}
/*
* Set FDs created by virCommandSetOutputFD and virCommandSetErrorFD
* as non-blocking in the parent.
*/
void
virCommandNonblockingFDs(virCommandPtr cmd)
{
if (!cmd || cmd->has_error)
return;
cmd->flags |= VIR_EXEC_NONBLOCK;
}
/*
* Add an environment variable to the child created by a printf-style format
*/
void
virCommandAddEnvFormat(virCommandPtr cmd, const char *format, ...)
{
char *env;
va_list list;
if (!cmd || cmd->has_error)
return;
va_start(list, format);
if (virVasprintf(&env, format, list) < 0) {
cmd->has_error = ENOMEM;
va_end(list);
return;
}
va_end(list);
/* Arg plus trailing NULL. */
if (VIR_RESIZE_N(cmd->env, cmd->maxenv, cmd->nenv, 1 + 1) < 0) {
VIR_FREE(env);
cmd->has_error = ENOMEM;
return;
}
cmd->env[cmd->nenv++] = env;
}
/*
* Add an environment variable to the child
* using separate name & value strings
*/
void
virCommandAddEnvPair(virCommandPtr cmd, const char *name, const char *value)
{
virCommandAddEnvFormat(cmd, "%s=%s", name, value);
}
/*
* Add an environment variable to the child
* using a preformatted env string FOO=BAR
*/
void
virCommandAddEnvString(virCommandPtr cmd, const char *str)
{
char *env;
if (!cmd || cmd->has_error)
return;
if (!(env = strdup(str))) {
cmd->has_error = ENOMEM;
return;
}
/* env plus trailing NULL */
if (VIR_RESIZE_N(cmd->env, cmd->maxenv, cmd->nenv, 1 + 1) < 0) {
VIR_FREE(env);
cmd->has_error = ENOMEM;
return;
}
cmd->env[cmd->nenv++] = env;
}
/*
* Convert a buffer containing preformatted name=value into an
* environment variable of the child.
* Correctly transfers memory errors or contents from buf to cmd.
*/
void
virCommandAddEnvBuffer(virCommandPtr cmd, virBufferPtr buf)
{
if (!cmd || cmd->has_error) {
virBufferFreeAndReset(buf);
return;
}
/* env plus trailing NULL. */
if (virBufferError(buf) ||
VIR_RESIZE_N(cmd->env, cmd->maxenv, cmd->nenv, 1 + 1) < 0) {
cmd->has_error = ENOMEM;
virBufferFreeAndReset(buf);
return;
}
cmd->env[cmd->nenv++] = virBufferContentAndReset(buf);
}
/*
* Pass an environment variable to the child
* using current process' value
*/
void
virCommandAddEnvPass(virCommandPtr cmd, const char *name)
{
char *value;
if (!cmd || cmd->has_error)
return;
value = getenv(name);
if (value)
virCommandAddEnvPair(cmd, name, value);
}
/*
* Set LC_ALL to C, and propagate other essential environment
* variables from the parent process.
*/
void
virCommandAddEnvPassCommon(virCommandPtr cmd)
{
if (!cmd || cmd->has_error)
return;
/* Attempt to Pre-allocate; allocation failure will be detected
* later during virCommandAdd*. */
ignore_value(VIR_RESIZE_N(cmd->env, cmd->maxenv, cmd->nenv, 9));
virCommandAddEnvPair(cmd, "LC_ALL", "C");
virCommandAddEnvPass(cmd, "LD_PRELOAD");
virCommandAddEnvPass(cmd, "LD_LIBRARY_PATH");
virCommandAddEnvPass(cmd, "PATH");
virCommandAddEnvPass(cmd, "HOME");
virCommandAddEnvPass(cmd, "USER");
virCommandAddEnvPass(cmd, "LOGNAME");
virCommandAddEnvPass(cmd, "TMPDIR");
}
/*
* Add a command line argument to the child
*/
void
virCommandAddArg(virCommandPtr cmd, const char *val)
{
char *arg;
if (!cmd || cmd->has_error)
return;
if (!(arg = strdup(val))) {
cmd->has_error = ENOMEM;
return;
}
/* Arg plus trailing NULL. */
if (VIR_RESIZE_N(cmd->args, cmd->maxargs, cmd->nargs, 1 + 1) < 0) {
VIR_FREE(arg);
cmd->has_error = ENOMEM;
return;
}
cmd->args[cmd->nargs++] = arg;
}
/*
* Convert a buffer into a command line argument to the child.
* Correctly transfers memory errors or contents from buf to cmd.
*/
void
virCommandAddArgBuffer(virCommandPtr cmd, virBufferPtr buf)
{
if (!cmd || cmd->has_error) {
virBufferFreeAndReset(buf);
return;
}
/* Arg plus trailing NULL. */
if (virBufferError(buf) ||
VIR_RESIZE_N(cmd->args, cmd->maxargs, cmd->nargs, 1 + 1) < 0) {
cmd->has_error = ENOMEM;
virBufferFreeAndReset(buf);
return;
}
cmd->args[cmd->nargs++] = virBufferContentAndReset(buf);
}
/*
* Add a command line argument created by a printf-style format
*/
void
virCommandAddArgFormat(virCommandPtr cmd, const char *format, ...)
{
char *arg;
va_list list;
if (!cmd || cmd->has_error)
return;
va_start(list, format);
if (virVasprintf(&arg, format, list) < 0) {
cmd->has_error = ENOMEM;
va_end(list);
return;
}
va_end(list);
/* Arg plus trailing NULL. */
if (VIR_RESIZE_N(cmd->args, cmd->maxargs, cmd->nargs, 1 + 1) < 0) {
VIR_FREE(arg);
cmd->has_error = ENOMEM;
return;
}
cmd->args[cmd->nargs++] = arg;
}
/*
* Add "NAME=VAL" as a single command line argument to the child
*/
void
virCommandAddArgPair(virCommandPtr cmd, const char *name, const char *val)
{
virCommandAddArgFormat(cmd, "%s=%s", name, val);
}
/*
* Add a NULL terminated list of args
*/
void
virCommandAddArgSet(virCommandPtr cmd, const char *const*vals)
{
int narg = 0;
if (!cmd || cmd->has_error)
return;
if (vals[0] == NULL) {
cmd->has_error = EINVAL;
return;
}
while (vals[narg] != NULL)
narg++;
/* narg plus trailing NULL. */
if (VIR_RESIZE_N(cmd->args, cmd->maxargs, cmd->nargs, narg + 1) < 0) {
cmd->has_error = ENOMEM;
return;
}
narg = 0;
while (vals[narg] != NULL) {
char *arg = strdup(vals[narg++]);
if (!arg) {
cmd->has_error = ENOMEM;
return;
}
cmd->args[cmd->nargs++] = arg;
}
}
/*
* Add a NULL terminated list of args
*/
void
virCommandAddArgList(virCommandPtr cmd, ...)
{
va_list list;
int narg = 0;
if (!cmd || cmd->has_error)
return;
va_start(list, cmd);
while (va_arg(list, const char *) != NULL)
narg++;
va_end(list);
/* narg plus trailing NULL. */
if (VIR_RESIZE_N(cmd->args, cmd->maxargs, cmd->nargs, narg + 1) < 0) {
cmd->has_error = ENOMEM;
return;
}
va_start(list, cmd);
while (1) {
char *arg = va_arg(list, char *);
if (!arg)
break;
arg = strdup(arg);
if (!arg) {
cmd->has_error = ENOMEM;
va_end(list);
return;
}
cmd->args[cmd->nargs++] = arg;
}
va_end(list);
}
/*
* Set the working directory of a non-daemon child process, rather
* than the parent's working directory. Daemons automatically get /
* without using this call.
*/
void
virCommandSetWorkingDirectory(virCommandPtr cmd, const char *pwd)
{
if (!cmd || cmd->has_error)
return;
if (cmd->pwd) {
cmd->has_error = -1;
VIR_DEBUG("cannot set directory twice");
} else {
cmd->pwd = strdup(pwd);
if (!cmd->pwd)
cmd->has_error = ENOMEM;
}
}
/*
* Feed the child's stdin from a string buffer
*/
void
virCommandSetInputBuffer(virCommandPtr cmd, const char *inbuf)
{
if (!cmd || cmd->has_error)
return;
if (cmd->infd != -1 || cmd->inbuf) {
cmd->has_error = -1;
VIR_DEBUG("cannot specify input twice");
return;
}
cmd->inbuf = strdup(inbuf);
if (!cmd->inbuf)
cmd->has_error = ENOMEM;
}
/*
* Capture the child's stdout to a string buffer. *outbuf is
* guaranteed to be allocated after successful virCommandRun or
* virCommandWait, and is best-effort allocated after failed
* virCommandRun; caller is responsible for freeing *outbuf.
*/
void
virCommandSetOutputBuffer(virCommandPtr cmd, char **outbuf)
{
*outbuf = NULL;
if (!cmd || cmd->has_error)
return;
if (cmd->outfdptr) {
cmd->has_error = -1;
VIR_DEBUG("cannot specify output twice");
return;
}
cmd->outbuf = outbuf;
cmd->outfdptr = &cmd->outfd;
}
/*
* Capture the child's stderr to a string buffer. *errbuf is
* guaranteed to be allocated after successful virCommandRun or
* virCommandWait, and is best-effort allocated after failed
* virCommandRun; caller is responsible for freeing *errbuf.
*/
void
virCommandSetErrorBuffer(virCommandPtr cmd, char **errbuf)
{
*errbuf = NULL;
if (!cmd || cmd->has_error)
return;
if (cmd->errfdptr) {
cmd->has_error = -1;
VIR_DEBUG("cannot specify stderr twice");
return;
}
cmd->errbuf = errbuf;
cmd->errfdptr = &cmd->errfd;
}
/*
* Attach a file descriptor to the child's stdin
*/
void
virCommandSetInputFD(virCommandPtr cmd, int infd)
{
if (!cmd || cmd->has_error)
return;
if (cmd->infd != -1 || cmd->inbuf) {
cmd->has_error = -1;
VIR_DEBUG("cannot specify input twice");
return;
}
if (infd < 0) {
cmd->has_error = -1;
VIR_DEBUG("cannot specify invalid input fd");
return;
}
cmd->infd = infd;
}
/*
* Attach a file descriptor to the child's stdout
*/
void
virCommandSetOutputFD(virCommandPtr cmd, int *outfd)
{
if (!cmd || cmd->has_error)
return;
if (cmd->outfdptr) {
cmd->has_error = -1;
VIR_DEBUG("cannot specify output twice");
return;
}
cmd->outfdptr = outfd;
}
/*
* Attach a file descriptor to the child's stderr
*/
void
virCommandSetErrorFD(virCommandPtr cmd, int *errfd)
{
if (!cmd || cmd->has_error)
return;
if (cmd->errfdptr) {
cmd->has_error = -1;
VIR_DEBUG("cannot specify stderr twice");
return;
}
cmd->errfdptr = errfd;
}
/*
* Run HOOK(OPAQUE) in the child as the last thing before changing
* directories, dropping capabilities, and executing the new process.
* Force the child to fail if HOOK does not return zero.
*/
void
virCommandSetPreExecHook(virCommandPtr cmd, virExecHook hook, void *opaque)
{
if (!cmd || cmd->has_error)
return;
if (cmd->hook) {
cmd->has_error = -1;
VIR_DEBUG("cannot specify hook twice");
return;
}
cmd->hook = hook;
cmd->opaque = opaque;
}
/*
* Call after adding all arguments and environment settings, but before
* Run/RunAsync, to immediately output the environment and arguments of
* cmd to logfd. If virCommandRun cannot succeed (because of an
* out-of-memory condition while building cmd), nothing will be logged.
*/
void
virCommandWriteArgLog(virCommandPtr cmd, int logfd)
{
int ioError = 0;
size_t i;
/* Any errors will be reported later by virCommandRun, which means
* no command will be run, so there is nothing to log. */
if (!cmd || cmd->has_error)
return;
for (i = 0 ; i < cmd->nenv ; i++) {
if (safewrite(logfd, cmd->env[i], strlen(cmd->env[i])) < 0)
ioError = errno;
if (safewrite(logfd, " ", 1) < 0)
ioError = errno;
}
for (i = 0 ; i < cmd->nargs ; i++) {
if (safewrite(logfd, cmd->args[i], strlen(cmd->args[i])) < 0)
ioError = errno;
if (safewrite(logfd, i == cmd->nargs - 1 ? "\n" : " ", 1) < 0)
ioError = errno;
}
if (ioError) {
char ebuf[1024];
VIR_WARN("Unable to write command %s args to logfile: %s",
cmd->args[0], virStrerror(ioError, ebuf, sizeof ebuf));
}
}
/*
* Call after adding all arguments and environment settings, but before
* Run/RunAsync, to return a string representation of the environment and
* arguments of cmd. If virCommandRun cannot succeed (because of an
* out-of-memory condition while building cmd), NULL will be returned.
* Caller is responsible for freeing the resulting string.
*/
char *
virCommandToString(virCommandPtr cmd)
{
size_t i;
virBuffer buf = VIR_BUFFER_INITIALIZER;
/* Cannot assume virCommandRun will be called; so report the error
* now. If virCommandRun is called, it will report the same error. */
if (!cmd ||cmd->has_error == ENOMEM) {
virReportOOMError();
return NULL;
}
if (cmd->has_error) {
virCommandError(VIR_ERR_INTERNAL_ERROR, "%s",
_("invalid use of command API"));
return NULL;
}
for (i = 0; i < cmd->nenv; i++) {
virBufferAdd(&buf, cmd->env[i], strlen(cmd->env[i]));
virBufferAddChar(&buf, ' ');
}
virBufferAdd(&buf, cmd->args[0], strlen(cmd->args[0]));
for (i = 1; i < cmd->nargs; i++) {
virBufferAddChar(&buf, ' ');
virBufferAdd(&buf, cmd->args[i], strlen(cmd->args[i]));
}
if (virBufferError(&buf)) {
virBufferFreeAndReset(&buf);
virReportOOMError();
return NULL;
}
return virBufferContentAndReset(&buf);
}
/*
* Translate an exit status into a malloc'd string. Generic helper
* for virCommandRun, virCommandWait, and virPidWait status argument,
* as well as raw waitpid and older virRun status.
*/
char *
virCommandTranslateStatus(int status)
{
char *buf;
if (WIFEXITED(status)) {
virAsprintf(&buf, _("exit status %d"), WEXITSTATUS(status));
} else if (WIFSIGNALED(status)) {
virAsprintf(&buf, _("fatal signal %d"), WTERMSIG(status));
} else {
virAsprintf(&buf, _("invalid value %d"), status);
}
return buf;
}
/*
* Manage input and output to the child process.
*/
static int
virCommandProcessIO(virCommandPtr cmd)
{
int infd = -1, outfd = -1, errfd = -1;
size_t inlen = 0, outlen = 0, errlen = 0;
size_t inoff = 0;
int ret = 0;
/* With an input buffer, feed data to child
* via pipe */
if (cmd->inbuf) {
inlen = strlen(cmd->inbuf);
infd = cmd->inpipe;
}
/* With out/err buffer, the outfd/errfd have been filled with an
* FD for us. Guarantee an allocated string with partial results
* even if we encounter a later failure, as well as freeing any
* results accumulated over a prior run of the same command. */
if (cmd->outbuf) {
outfd = cmd->outfd;
if (VIR_REALLOC_N(*cmd->outbuf, 1) < 0) {
virReportOOMError();
ret = -1;
}
}
if (cmd->errbuf) {
errfd = cmd->errfd;
if (VIR_REALLOC_N(*cmd->errbuf, 1) < 0) {
virReportOOMError();
ret = -1;
}
}
if (ret == -1)
goto cleanup;
ret = -1;
for (;;) {
int i;
struct pollfd fds[3];
int nfds = 0;
if (infd != -1) {
fds[nfds].fd = infd;
fds[nfds].events = POLLOUT;
nfds++;
}
if (outfd != -1) {
fds[nfds].fd = outfd;
fds[nfds].events = POLLIN;
nfds++;
}
if (errfd != -1) {
fds[nfds].fd = errfd;
fds[nfds].events = POLLIN;
nfds++;
}
if (nfds == 0)
break;
if (poll(fds, nfds, -1) < 0) {
if ((errno == EAGAIN) || (errno == EINTR))
continue;
virReportSystemError(errno, "%s",
_("unable to poll on child"));
goto cleanup;
}
for (i = 0; i < nfds ; i++) {
if (fds[i].fd == errfd ||
fds[i].fd == outfd) {
char data[1024];
char **buf;
size_t *len;
int done;
if (fds[i].fd == outfd) {
buf = cmd->outbuf;
len = &outlen;
} else {
buf = cmd->errbuf;
len = &errlen;
}
/* Silence a false positive from clang. */
sa_assert(buf);
done = read(fds[i].fd, data, sizeof(data));
if (done < 0) {
if (errno != EINTR &&
errno != EAGAIN) {
virReportSystemError(errno, "%s",
(fds[i].fd == outfd) ?
_("unable to read child stdout") :
_("unable to read child stderr"));
goto cleanup;
}
} else if (done == 0) {
if (fds[i].fd == outfd)
outfd = -1;
else
errfd = -1;
} else {
if (VIR_REALLOC_N(*buf, *len + done + 1) < 0) {
virReportOOMError();
goto cleanup;
}
memcpy(*buf + *len, data, done);
*len += done;
}
} else {
int done;
/* Coverity 5.3.0 can't see that we only get here if
* infd is in the set because it was non-negative. */
sa_assert(infd != -1);
done = write(infd, cmd->inbuf + inoff,
inlen - inoff);
if (done < 0) {
if (errno != EINTR &&
errno != EAGAIN) {
virReportSystemError(errno, "%s",
_("unable to write to child input"));
goto cleanup;
}
} else {
inoff += done;
if (inoff == inlen) {
int tmpfd = infd;
if (VIR_CLOSE(infd) < 0)
VIR_DEBUG("ignoring failed close on fd %d", tmpfd);
}
}
}
}
}
ret = 0;
cleanup:
if (cmd->outbuf && *cmd->outbuf)
(*cmd->outbuf)[outlen] = '\0';
if (cmd->errbuf && *cmd->errbuf)
(*cmd->errbuf)[errlen] = '\0';
return ret;
}
/*
* Exec the command, replacing the current process. Meant to be called
* after already forking / cloning, so does not attempt to daemonize or
* preserve any FDs.
*
* Returns -1 on any error executing the command.
* Will not return on success.
*/
#ifndef WIN32
int virCommandExec(virCommandPtr cmd)
{
if (!cmd ||cmd->has_error == ENOMEM) {
virReportOOMError();
return -1;
}
if (cmd->has_error) {
virCommandError(VIR_ERR_INTERNAL_ERROR, "%s",
_("invalid use of command API"));
return -1;
}
return execve(cmd->args[0], cmd->args, cmd->env);
}
#else
int virCommandExec(virCommandPtr cmd ATTRIBUTE_UNUSED)
{
/* Mingw execve() has a broken signature. Disable this
* function until gnulib fixes the signature, since we
* don't really need this on Win32 anyway.
*/
virReportSystemError(ENOSYS, "%s",
_("Executing new processes is not supported on Win32 platform"));
return -1;
}
#endif
/*
* Run the command and wait for completion.
* Returns -1 on any error executing the
* command. Returns 0 if the command executed,
* with the exit status set
*/
int
virCommandRun(virCommandPtr cmd, int *exitstatus)
{
int ret = 0;
char *outbuf = NULL;
char *errbuf = NULL;
int infd[2] = { -1, -1 };
struct stat st;
bool string_io;
bool async_io = false;
char *str;
if (!cmd ||cmd->has_error == ENOMEM) {
virReportOOMError();
return -1;
}
if (cmd->has_error) {
virCommandError(VIR_ERR_INTERNAL_ERROR, "%s",
_("invalid use of command API"));
return -1;
}
/* Avoid deadlock, by requiring that any open fd not under our
* control must be visiting a regular file, or that we are
* daemonized and no string io is required. */
string_io = cmd->inbuf || cmd->outbuf || cmd->errbuf;
if (cmd->infd != -1 &&
(fstat(cmd->infd, &st) < 0 || !S_ISREG(st.st_mode)))
async_io = true;
if (cmd->outfdptr && cmd->outfdptr != &cmd->outfd &&
(*cmd->outfdptr == -1 ||
fstat(*cmd->outfdptr, &st) < 0 || !S_ISREG(st.st_mode)))
async_io = true;
if (cmd->errfdptr && cmd->errfdptr != &cmd->errfd &&
(*cmd->errfdptr == -1 ||
fstat(*cmd->errfdptr, &st) < 0 || !S_ISREG(st.st_mode)))
async_io = true;
if (async_io) {
if (!(cmd->flags & VIR_EXEC_DAEMON) || string_io) {
virCommandError(VIR_ERR_INTERNAL_ERROR, "%s",
_("cannot mix caller fds with blocking execution"));
return -1;
}
} else {
if ((cmd->flags & VIR_EXEC_DAEMON) && string_io) {
virCommandError(VIR_ERR_INTERNAL_ERROR, "%s",
_("cannot mix string I/O with daemon"));
return -1;
}
}
/* If we have an input buffer, we need
* a pipe to feed the data to the child */
if (cmd->inbuf) {
if (pipe(infd) < 0) {
virReportSystemError(errno, "%s",
_("unable to open pipe"));
cmd->has_error = -1;
return -1;
}
cmd->infd = infd[0];
cmd->inpipe = infd[1];
}
/* If caller hasn't requested capture of stdout/err, then capture
* it ourselves so we can log it. But the intermediate child for
* a daemon has no expected output, and we don't want our
* capturing pipes passed on to the daemon grandchild.
*/
if (!(cmd->flags & VIR_EXEC_DAEMON)) {
if (!cmd->outfdptr) {
cmd->outfdptr = &cmd->outfd;
cmd->outbuf = &outbuf;
string_io = true;
}
if (!cmd->errfdptr) {
cmd->errfdptr = &cmd->errfd;
cmd->errbuf = &errbuf;
string_io = true;
}
}
cmd->flags |= VIR_EXEC_RUN_SYNC;
if (virCommandRunAsync(cmd, NULL) < 0) {
if (cmd->inbuf) {
int tmpfd = infd[0];
if (VIR_CLOSE(infd[0]) < 0)
VIR_DEBUG("ignoring failed close on fd %d", tmpfd);
tmpfd = infd[1];
if (VIR_CLOSE(infd[1]) < 0)
VIR_DEBUG("ignoring failed close on fd %d", tmpfd);
}
cmd->has_error = -1;
return -1;
}
if (string_io)
ret = virCommandProcessIO(cmd);
if (virCommandWait(cmd, exitstatus) < 0)
ret = -1;
str = (exitstatus ? virCommandTranslateStatus(*exitstatus)
: (char *) "status 0");
VIR_DEBUG("Result %s, stdout: '%s' stderr: '%s'",
NULLSTR(str),
cmd->outbuf ? NULLSTR(*cmd->outbuf) : "(null)",
cmd->errbuf ? NULLSTR(*cmd->errbuf) : "(null)");
if (exitstatus)
VIR_FREE(str);
/* Reset any capturing, in case caller runs
* this identical command again */
if (cmd->inbuf) {
int tmpfd = infd[0];
if (VIR_CLOSE(infd[0]) < 0)
VIR_DEBUG("ignoring failed close on fd %d", tmpfd);
tmpfd = infd[1];
if (VIR_CLOSE(infd[1]) < 0)
VIR_DEBUG("ignoring failed close on fd %d", tmpfd);
}
if (cmd->outbuf == &outbuf) {
int tmpfd = cmd->outfd;
if (VIR_CLOSE(cmd->outfd) < 0)
VIR_DEBUG("ignoring failed close on fd %d", tmpfd);
cmd->outfdptr = NULL;
cmd->outbuf = NULL;
VIR_FREE(outbuf);
}
if (cmd->errbuf == &errbuf) {
int tmpfd = cmd->errfd;
if (VIR_CLOSE(cmd->errfd) < 0)
VIR_DEBUG("ignoring failed close on fd %d", tmpfd);
cmd->errfdptr = NULL;
cmd->errbuf = NULL;
VIR_FREE(errbuf);
}
return ret;
}
/*
* Perform all virCommand-specific actions, along with the user hook.
*/
static int
virCommandHook(void *data)
{
virCommandPtr cmd = data;
int res = 0;
if (cmd->hook) {
VIR_DEBUG("Run hook %p %p", cmd->hook, cmd->opaque);
res = cmd->hook(cmd->opaque);
VIR_DEBUG("Done hook %d", res);
}
if (res == 0 && cmd->pwd) {
VIR_DEBUG("Running child in %s", cmd->pwd);
res = chdir(cmd->pwd);
if (res < 0) {
virReportSystemError(errno,
_("Unable to change to %s"), cmd->pwd);
}
}
if (cmd->handshake) {
char c = res < 0 ? '0' : '1';
int rv;
VIR_DEBUG("Notifying parent for handshake start on %d", cmd->handshakeWait[1]);
if (safewrite(cmd->handshakeWait[1], &c, sizeof(c)) != sizeof(c)) {
virReportSystemError(errno, "%s", _("Unable to notify parent process"));
return -1;
}
/* On failure we pass the error message back to parent,
* so they don't have to dig through stderr logs
*/
if (res < 0) {
virErrorPtr err = virGetLastError();
const char *msg = err ? err->message :
_("Unknown failure during hook execution");
size_t len = strlen(msg) + 1;
if (safewrite(cmd->handshakeWait[1], msg, len) != len) {
virReportSystemError(errno, "%s", _("Unable to send error to parent process"));
return -1;
}
return -1;
}
VIR_DEBUG("Waiting on parent for handshake complete on %d", cmd->handshakeNotify[0]);
if ((rv = saferead(cmd->handshakeNotify[0], &c, sizeof(c))) != sizeof(c)) {
if (rv < 0)
virReportSystemError(errno, "%s", _("Unable to wait on parent process"));
else
virReportSystemError(EIO, "%s", _("libvirtd quit during handshake"));
return -1;
}
if (c != '1') {
virReportSystemError(EINVAL, _("Unexpected confirm code '%c' from parent process"), c);
return -1;
}
VIR_FORCE_CLOSE(cmd->handshakeWait[1]);
VIR_FORCE_CLOSE(cmd->handshakeNotify[0]);
}
VIR_DEBUG("Hook is done %d", res);
return res;
}
/*
* Run the command asynchronously
* Returns -1 on any error executing the
* command. Returns 0 if the command executed.
*
* There are two approaches to child process cleanup.
* 1. Use auto-cleanup, by passing NULL for pid. The child will be
* auto-reaped by virCommandFree, unless you reap it earlier via
* virCommandWait or virCommandAbort. Good for where cmd is in
* scope for the duration of the child process.
* 2. Use manual cleanup, by passing the address of a pid_t variable
* for pid. While cmd is still in scope, you may reap the child via
* virCommandWait or virCommandAbort. But after virCommandFree, if
* you have not yet reaped the child, then it continues to run until
* you call virPidWait or virPidAbort.
*/
int
virCommandRunAsync(virCommandPtr cmd, pid_t *pid)
{
int ret;
char *str;
int i;
bool synchronous = false;
if (!cmd || cmd->has_error == ENOMEM) {
virReportOOMError();
return -1;
}
if (cmd->has_error) {
virCommandError(VIR_ERR_INTERNAL_ERROR, "%s",
_("invalid use of command API"));
return -1;
}
synchronous = cmd->flags & VIR_EXEC_RUN_SYNC;
cmd->flags &= ~VIR_EXEC_RUN_SYNC;
/* Buffer management can only be requested via virCommandRun. */
if ((cmd->inbuf && cmd->infd == -1) ||
(cmd->outbuf && cmd->outfdptr != &cmd->outfd) ||
(cmd->errbuf && cmd->errfdptr != &cmd->errfd)) {
virCommandError(VIR_ERR_INTERNAL_ERROR, "%s",
_("cannot mix string I/O with asynchronous command"));
return -1;
}
if (cmd->pid != -1) {
virCommandError(VIR_ERR_INTERNAL_ERROR,
_("command is already running as pid %d"),
cmd->pid);
return -1;
}
if (!synchronous && (cmd->flags & VIR_EXEC_DAEMON)) {
virCommandError(VIR_ERR_INTERNAL_ERROR, "%s",
_("daemonized command cannot use virCommandRunAsync"));
return -1;
}
if (cmd->pwd && (cmd->flags & VIR_EXEC_DAEMON)) {
virCommandError(VIR_ERR_INTERNAL_ERROR,
_("daemonized command cannot set working directory %s"),
cmd->pwd);
return -1;
}
if (cmd->pidfile && !(cmd->flags & VIR_EXEC_DAEMON)) {
virCommandError(VIR_ERR_INTERNAL_ERROR, "%s",
_("creation of pid file requires daemonized command"));
return -1;
}
str = virCommandToString(cmd);
VIR_DEBUG("About to run %s", str ? str : cmd->args[0]);
VIR_FREE(str);
ret = virExecWithHook((const char *const *)cmd->args,
(const char *const *)cmd->env,
&cmd->preserve,
&cmd->pid,
cmd->infd,
cmd->outfdptr,
cmd->errfdptr,
cmd->flags,
virCommandHook,
cmd,
cmd->pidfile);
VIR_DEBUG("Command result %d, with PID %d",
ret, (int)cmd->pid);
for (i = STDERR_FILENO + 1; i < FD_SETSIZE; i++) {
if (FD_ISSET(i, &cmd->transfer)) {
int tmpfd = i;
VIR_FORCE_CLOSE(tmpfd);
FD_CLR(i, &cmd->transfer);
}
}
if (ret == 0 && pid)
*pid = cmd->pid;
else
cmd->reap = true;
return ret;
}
/*
* Wait for a child process to complete.
* Return -1 on any error waiting for
* completion. Returns 0 if the command
* finished with the exit status set
*/
int
virPidWait(pid_t pid, int *exitstatus)
{
int ret;
int status;
if (pid <= 0) {
virReportSystemError(EINVAL, _("unable to wait for process %d"), pid);
return -1;
}
/* Wait for intermediate process to exit */
while ((ret = waitpid(pid, &status, 0)) == -1 &&
errno == EINTR);
if (ret == -1) {
virReportSystemError(errno, _("unable to wait for process %d"), pid);
return -1;
}
if (exitstatus == NULL) {
if (status != 0) {
char *st = virCommandTranslateStatus(status);
virCommandError(VIR_ERR_INTERNAL_ERROR,
_("Child process (%d) status unexpected: %s"),
pid, NULLSTR(st));
VIR_FREE(st);
return -1;
}
} else {
*exitstatus = status;
}
return 0;
}
/*
* Wait for the async command to complete.
* Return -1 on any error waiting for
* completion. Returns 0 if the command
* finished with the exit status set
*/
int
virCommandWait(virCommandPtr cmd, int *exitstatus)
{
int ret;
int status = 0;
if (!cmd ||cmd->has_error == ENOMEM) {
virReportOOMError();
return -1;
}
if (cmd->has_error) {
virCommandError(VIR_ERR_INTERNAL_ERROR, "%s",
_("invalid use of command API"));
return -1;
}
if (cmd->pid == -1) {
virCommandError(VIR_ERR_INTERNAL_ERROR, "%s",
_("command is not yet running"));
return -1;
}
/* If virPidWait reaps pid but then returns failure because
* exitstatus was NULL, then a second virCommandWait would risk
* calling waitpid on an unrelated process. Besides, that error
* message is not as detailed as what we can provide. So, we
* guarantee that virPidWait only fails due to failure to wait,
* and repeat the exitstatus check code ourselves. */
ret = virPidWait(cmd->pid, exitstatus ? exitstatus : &status);
if (ret == 0) {
cmd->pid = -1;
cmd->reap = false;
if (status) {
char *str = virCommandToString(cmd);
char *st = virCommandTranslateStatus(status);
virCommandError(VIR_ERR_INTERNAL_ERROR,
_("Child process (%s) status unexpected: %s"),
str ? str : cmd->args[0], NULLSTR(st));
VIR_FREE(str);
VIR_FREE(st);
return -1;
}
}
return ret;
}
#ifndef WIN32
/*
* Abort a child process if PID is positive and that child is still
* running, without issuing any errors or affecting errno. Designed
* for error paths where some but not all paths to the cleanup code
* might have started the child process.
*/
void
virPidAbort(pid_t pid)
{
int saved_errno;
int ret;
int status;
char *tmp = NULL;
if (pid <= 0)
return;
/* See if intermediate process has exited; if not, try a nice
* SIGTERM followed by a more severe SIGKILL.
*/
saved_errno = errno;
VIR_DEBUG("aborting child process %d", pid);
while ((ret = waitpid(pid, &status, WNOHANG)) == -1 &&
errno == EINTR);
if (ret == pid) {
tmp = virCommandTranslateStatus(status);
VIR_DEBUG("process has ended: %s", tmp);
goto cleanup;
} else if (ret == 0) {
VIR_DEBUG("trying SIGTERM to child process %d", pid);
kill(pid, SIGTERM);
usleep(10 * 1000);
while ((ret = waitpid(pid, &status, WNOHANG)) == -1 &&
errno == EINTR);
if (ret == pid) {
tmp = virCommandTranslateStatus(status);
VIR_DEBUG("process has ended: %s", tmp);
goto cleanup;
} else if (ret == 0) {
VIR_DEBUG("trying SIGKILL to child process %d", pid);
kill(pid, SIGKILL);
while ((ret = waitpid(pid, &status, 0)) == -1 &&
errno == EINTR);
if (ret == pid) {
tmp = virCommandTranslateStatus(status);
VIR_DEBUG("process has ended: %s", tmp);
goto cleanup;
}
}
}
VIR_DEBUG("failed to reap child %d, abandoning it", pid);
cleanup:
VIR_FREE(tmp);
errno = saved_errno;
}
/*
* Abort an async command if it is running, without issuing
* any errors or affecting errno. Designed for error paths
* where some but not all paths to the cleanup code might
* have started the child process.
*/
void
virCommandAbort(virCommandPtr cmd)
{
if (!cmd || cmd->pid == -1)
return;
virPidAbort(cmd->pid);
cmd->pid = -1;
cmd->reap = false;
}
#else /* WIN32 */
void
virPidAbort(pid_t pid)
{
/* Not yet ported to mingw. Any volunteers? */
VIR_DEBUG("failed to reap child %d, abandoning it", pid);
}
void
virCommandAbort(virCommandPtr cmd ATTRIBUTE_UNUSED)
{
/* Mingw lacks WNOHANG and kill(). But since we haven't ported
* virExecWithHook to mingw yet, there's no process to be killed,
* making this implementation trivially correct for now :) */
}
#endif
void virCommandRequireHandshake(virCommandPtr cmd)
{
if (!cmd || cmd->has_error)
return;
if (cmd->handshake) {
cmd->has_error = -1;
VIR_DEBUG("Cannot require handshake twice");
return;
}
if (pipe(cmd->handshakeWait) < 0) {
cmd->has_error = errno;
return;
}
if (pipe(cmd->handshakeNotify) < 0) {
VIR_FORCE_CLOSE(cmd->handshakeWait[0]);
VIR_FORCE_CLOSE(cmd->handshakeWait[1]);
cmd->has_error = errno;
return;
}
VIR_DEBUG("Transfer handshake wait=%d notify=%d",
cmd->handshakeWait[1], cmd->handshakeNotify[0]);
virCommandTransferFD(cmd, cmd->handshakeWait[1]);
virCommandTransferFD(cmd, cmd->handshakeNotify[0]);
cmd->handshake = true;
}
int virCommandHandshakeWait(virCommandPtr cmd)
{
char c;
int rv;
if (!cmd ||cmd->has_error == ENOMEM) {
virReportOOMError();
return -1;
}
if (cmd->has_error || !cmd->handshake) {
virCommandError(VIR_ERR_INTERNAL_ERROR, "%s",
_("invalid use of command API"));
return -1;
}
if (cmd->handshakeWait[0] == -1) {
virCommandError(VIR_ERR_INTERNAL_ERROR, "%s",
_("Handshake is already complete"));
return -1;
}
VIR_DEBUG("Wait for handshake on %d", cmd->handshakeWait[0]);
if ((rv = saferead(cmd->handshakeWait[0], &c, sizeof(c))) != sizeof(c)) {
if (rv < 0)
virReportSystemError(errno, "%s", _("Unable to wait for child process"));
else
virReportSystemError(EIO, "%s", _("Child process quit during startup handshake"));
VIR_FORCE_CLOSE(cmd->handshakeWait[0]);
return -1;
}
if (c != '1') {
char *msg;
ssize_t len;
if (VIR_ALLOC_N(msg, 1024) < 0) {
virReportOOMError();
VIR_FORCE_CLOSE(cmd->handshakeWait[0]);
return -1;
}
if ((len = saferead(cmd->handshakeWait[0], msg, 1024)) < 0) {
VIR_FORCE_CLOSE(cmd->handshakeWait[0]);
VIR_FREE(msg);
virReportSystemError(errno, "%s", _("No error message from child failure"));
return -1;
}
VIR_FORCE_CLOSE(cmd->handshakeWait[0]);
msg[len-1] = '\0';
virCommandError(VIR_ERR_INTERNAL_ERROR, "%s", msg);
VIR_FREE(msg);
return -1;
}
VIR_FORCE_CLOSE(cmd->handshakeWait[0]);
return 0;
}
int virCommandHandshakeNotify(virCommandPtr cmd)
{
char c = '1';
if (!cmd ||cmd->has_error == ENOMEM) {
virReportOOMError();
return -1;
}
if (cmd->has_error || !cmd->handshake) {
virCommandError(VIR_ERR_INTERNAL_ERROR, "%s",
_("invalid use of command API"));
return -1;
}
if (cmd->handshakeNotify[1] == -1) {
virCommandError(VIR_ERR_INTERNAL_ERROR, "%s",
_("Handshake is already complete"));
return -1;
}
VIR_DEBUG("Notify handshake on %d", cmd->handshakeWait[0]);
if (safewrite(cmd->handshakeNotify[1], &c, sizeof(c)) != sizeof(c)) {
virReportSystemError(errno, "%s", _("Unable to notify child process"));
VIR_FORCE_CLOSE(cmd->handshakeNotify[1]);
return -1;
}
VIR_FORCE_CLOSE(cmd->handshakeNotify[1]);
return 0;
}
/*
* Release all resources. The only exception is that if you called
* virCommandRunAsync with a non-null pid, then the asynchronous child
* is not reaped, and you must call virPidWait() yourself.
*/
void
virCommandFree(virCommandPtr cmd)
{
int i;
if (!cmd)
return;
for (i = STDERR_FILENO + 1; i < FD_SETSIZE; i++) {
if (FD_ISSET(i, &cmd->transfer)) {
int tmpfd = i;
VIR_FORCE_CLOSE(tmpfd);
}
}
VIR_FREE(cmd->inbuf);
VIR_FORCE_CLOSE(cmd->outfd);
VIR_FORCE_CLOSE(cmd->errfd);
for (i = 0 ; i < cmd->nargs ; i++)
VIR_FREE(cmd->args[i]);
VIR_FREE(cmd->args);
for (i = 0 ; i < cmd->nenv ; i++)
VIR_FREE(cmd->env[i]);
VIR_FREE(cmd->env);
VIR_FREE(cmd->pwd);
if (cmd->handshake) {
/* The other 2 fds in these arrays are closed
* due to use with virCommandTransferFD
*/
VIR_FORCE_CLOSE(cmd->handshakeWait[0]);
VIR_FORCE_CLOSE(cmd->handshakeNotify[1]);
}
VIR_FREE(cmd->pidfile);
if (cmd->reap)
virCommandAbort(cmd);
VIR_FREE(cmd);
}
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