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Merge pull request #10484 from yuwata/udev-spawn-simplify

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udev-event: cleanups about udev_event_spawn()
This commit is contained in:
Lennart Poettering 2018-10-24 10:57:45 +02:00 committed by GitHub
parent e7b48c45ae e81c3a4c5f
commit d1db1c438f
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GPG key ID: 4AEE18F83AFDEB23
2 changed files with 111 additions and 224 deletions
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332
src/udev/udev-event.c
View file

@ -4,18 +4,15 @@
#include <errno.h>
#include <fcntl.h>
#include <net/if.h>
#include <poll.h>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/epoll.h>
#include <sys/prctl.h>
#include <sys/signalfd.h>
#include <sys/wait.h>
#include <unistd.h>
#include "sd-event.h"
#include "alloc-util.h"
#include "device-private.h"
#include "fd-util.h"
#include "format-util.h"
#include "libudev-device-internal.h"
@ -32,9 +29,15 @@
typedef struct Spawn {
const char *cmd;
pid_t pid;
usec_t timeout_warn;
usec_t timeout;
usec_t timeout_warn_usec;
usec_t timeout_usec;
usec_t event_birth_usec;
bool accept_failure;
int fd_stdout;
int fd_stderr;
char *result;
size_t result_size;
size_t result_len;
} Spawn;
struct udev_event *udev_event_new(struct udev_device *dev) {
@ -405,186 +408,51 @@ out:
return l;
}
static int spawn_exec(struct udev_event *event,
const char *cmd, char *const argv[], char **envp,
int fd_stdout, int fd_stderr) {
_cleanup_close_ int fd = -1;
int r;
static int on_spawn_io(sd_event_source *s, int fd, uint32_t revents, void *userdata) {
Spawn *spawn = userdata;
char buf[4096], *p;
size_t size;
ssize_t l;
/* discard child output or connect to pipe */
fd = open("/dev/null", O_RDWR);
if (fd >= 0) {
r = dup2(fd, STDIN_FILENO);
if (r < 0)
log_warning_errno(errno, "redirecting stdin failed: %m");
assert(spawn);
assert(fd == spawn->fd_stdout || fd == spawn->fd_stderr);
assert(!spawn->result || spawn->result_len < spawn->result_size);
if (fd_stdout < 0) {
r = dup2(fd, STDOUT_FILENO);
if (r < 0)
log_warning_errno(errno, "redirecting stdout failed: %m");
}
if (fd_stderr < 0) {
r = dup2(fd, STDERR_FILENO);
if (r < 0)
log_warning_errno(errno, "redirecting stderr failed: %m");
}
} else
log_warning_errno(errno, "open /dev/null failed: %m");
/* connect pipes to std{out,err} */
if (fd_stdout >= 0) {
r = dup2(fd_stdout, STDOUT_FILENO);
if (r < 0)
log_warning_errno(errno, "redirecting stdout failed: %m");
fd_stdout = safe_close(fd_stdout);
if (fd == spawn->fd_stdout && spawn->result) {
p = spawn->result + spawn->result_len;
size = spawn->result_size - spawn->result_len;
} else {
p = buf;
size = sizeof(buf);
}
if (fd_stderr >= 0) {
r = dup2(fd_stderr, STDERR_FILENO);
if (r < 0)
log_warning_errno(errno, "redirecting stdout failed: %m");
l = read(fd, p, size - 1);
if (l < 0) {
if (errno != EAGAIN)
log_error_errno(errno, "Failed to read stdout of '%s': %m", spawn->cmd);
fd_stderr = safe_close(fd_stderr);
return 0;
}
/* terminate child in case parent goes away */
prctl(PR_SET_PDEATHSIG, SIGTERM);
p[l] = '\0';
if (fd == spawn->fd_stdout && spawn->result)
spawn->result_len += l;
/* restore sigmask before exec */
(void) reset_signal_mask();
/* Log output only if we watch stderr. */
if (l > 0 && spawn->fd_stderr >= 0) {
_cleanup_strv_free_ char **v = NULL;
char **q;
execve(argv[0], argv, envp);
v = strv_split_newlines(p);
if (!v)
return 0;
/* exec failed */
return log_error_errno(errno, "failed to execute '%s' '%s': %m", argv[0], cmd);
}
static void spawn_read(struct udev_event *event,
usec_t timeout_usec,
const char *cmd,
int fd_stdout, int fd_stderr,
char *result, size_t ressize) {
_cleanup_close_ int fd_ep = -1;
struct epoll_event ep_outpipe = {
.events = EPOLLIN,
.data.ptr = &fd_stdout,
};
struct epoll_event ep_errpipe = {
.events = EPOLLIN,
.data.ptr = &fd_stderr,
};
size_t respos = 0;
int r;
/* read from child if requested */
if (fd_stdout < 0 && fd_stderr < 0)
return;
fd_ep = epoll_create1(EPOLL_CLOEXEC);
if (fd_ep < 0) {
log_error_errno(errno, "error creating epoll fd: %m");
return;
STRV_FOREACH(q, v)
log_debug("'%s'(%s) '%s'", spawn->cmd,
fd == spawn->fd_stdout ? "out" : "err", *q);
}
if (fd_stdout >= 0) {
r = epoll_ctl(fd_ep, EPOLL_CTL_ADD, fd_stdout, &ep_outpipe);
if (r < 0) {
log_error_errno(errno, "fail to add stdout fd to epoll: %m");
return;
}
}
if (fd_stderr >= 0) {
r = epoll_ctl(fd_ep, EPOLL_CTL_ADD, fd_stderr, &ep_errpipe);
if (r < 0) {
log_error_errno(errno, "fail to add stderr fd to epoll: %m");
return;
}
}
/* read child output */
while (fd_stdout >= 0 || fd_stderr >= 0) {
int timeout;
int fdcount;
struct epoll_event ev[4];
int i;
if (timeout_usec > 0) {
usec_t age_usec;
age_usec = now(CLOCK_MONOTONIC) - event->birth_usec;
if (age_usec >= timeout_usec) {
log_error("timeout '%s'", cmd);
return;
}
timeout = ((timeout_usec - age_usec) / USEC_PER_MSEC) + MSEC_PER_SEC;
} else {
timeout = -1;
}
fdcount = epoll_wait(fd_ep, ev, ELEMENTSOF(ev), timeout);
if (fdcount < 0) {
if (errno == EINTR)
continue;
log_error_errno(errno, "failed to poll: %m");
return;
} else if (fdcount == 0) {
log_error("timeout '%s'", cmd);
return;
}
for (i = 0; i < fdcount; i++) {
int *fd = (int *)ev[i].data.ptr;
if (*fd < 0)
continue;
if (ev[i].events & EPOLLIN) {
ssize_t count;
char buf[4096];
count = read(*fd, buf, sizeof(buf)-1);
if (count <= 0)
continue;
buf[count] = '\0';
/* store stdout result */
if (result != NULL && *fd == fd_stdout) {
if (respos + count < ressize) {
memcpy(&result[respos], buf, count);
respos += count;
} else {
log_error("'%s' ressize %zu too short", cmd, ressize);
}
}
/* log debug output only if we watch stderr */
if (fd_stderr >= 0) {
char *pos;
char *line;
pos = buf;
while ((line = strsep(&pos, "\n"))) {
if (pos != NULL || line[0] != '\0')
log_debug("'%s'(%s) '%s'", cmd, *fd == fd_stdout ? "out" : "err" , line);
}
}
} else if (ev[i].events & EPOLLHUP) {
r = epoll_ctl(fd_ep, EPOLL_CTL_DEL, *fd, NULL);
if (r < 0) {
log_error_errno(errno, "failed to remove fd from epoll: %m");
return;
}
*fd = -1;
}
}
}
/* return the child's stdout string */
if (result != NULL)
result[respos] = '\0';
return 0;
}
static int on_spawn_timeout(sd_event_source *s, uint64_t usec, void *userdata) {
@ -595,8 +463,8 @@ static int on_spawn_timeout(sd_event_source *s, uint64_t usec, void *userdata) {
kill_and_sigcont(spawn->pid, SIGKILL);
log_error("spawned process '%s' ["PID_FMT"] timed out after %s, killing", spawn->cmd, spawn->pid,
format_timestamp_relative(timeout, sizeof(timeout), spawn->timeout));
log_error("Spawned process '%s' ["PID_FMT"] timed out after %s, killing", spawn->cmd, spawn->pid,
format_timestamp_relative(timeout, sizeof(timeout), spawn->timeout_usec));
return 1;
}
@ -607,8 +475,8 @@ static int on_spawn_timeout_warning(sd_event_source *s, uint64_t usec, void *use
assert(spawn);
log_warning("spawned process '%s' ["PID_FMT"] is taking longer than %s to complete", spawn->cmd, spawn->pid,
format_timestamp_relative(timeout, sizeof(timeout), spawn->timeout));
log_warning("Spawned process '%s' ["PID_FMT"] is taking longer than %s to complete", spawn->cmd, spawn->pid,
format_timestamp_relative(timeout, sizeof(timeout), spawn->timeout_warn_usec));
return 1;
}
@ -625,11 +493,10 @@ static int on_spawn_sigchld(sd_event_source *s, const siginfo_t *si, void *userd
sd_event_exit(sd_event_source_get_event(s), 0);
return 1;
} else if (spawn->accept_failure)
log_debug("Process '%s' failed with exit code %i.", spawn->cmd, si->si_status);
else
log_warning("Process '%s' failed with exit code %i.", spawn->cmd, si->si_status);
}
log_full(spawn->accept_failure ? LOG_DEBUG : LOG_WARNING,
"Process '%s' failed with exit code %i.", spawn->cmd, si->si_status);
break;
case CLD_KILLED:
case CLD_DUMPED:
@ -645,49 +512,52 @@ static int on_spawn_sigchld(sd_event_source *s, const siginfo_t *si, void *userd
return 1;
}
static int spawn_wait(struct udev_event *event,
usec_t timeout_usec,
usec_t timeout_warn_usec,
const char *cmd, pid_t pid,
bool accept_failure) {
Spawn spawn = {
.cmd = cmd,
.pid = pid,
.accept_failure = accept_failure,
};
static int spawn_wait(Spawn *spawn) {
_cleanup_(sd_event_unrefp) sd_event *e = NULL;
int r, ret;
assert(spawn);
r = sd_event_new(&e);
if (r < 0)
return r;
if (timeout_usec > 0) {
if (spawn->timeout_usec > 0) {
usec_t usec, age_usec;
usec = now(CLOCK_MONOTONIC);
age_usec = usec - event->birth_usec;
if (age_usec < timeout_usec) {
if (timeout_warn_usec > 0 && timeout_warn_usec < timeout_usec && age_usec < timeout_warn_usec) {
spawn.timeout_warn = timeout_warn_usec - age_usec;
age_usec = usec - spawn->event_birth_usec;
if (age_usec < spawn->timeout_usec) {
if (spawn->timeout_warn_usec > 0 &&
spawn->timeout_warn_usec < spawn->timeout_usec &&
spawn->timeout_warn_usec > age_usec) {
spawn->timeout_warn_usec -= age_usec;
r = sd_event_add_time(e, NULL, CLOCK_MONOTONIC,
usec + spawn.timeout_warn, USEC_PER_SEC,
on_spawn_timeout_warning, &spawn);
usec + spawn->timeout_warn_usec, USEC_PER_SEC,
on_spawn_timeout_warning, spawn);
if (r < 0)
return r;
}
spawn.timeout = timeout_usec - age_usec;
spawn->timeout_usec -= age_usec;
r = sd_event_add_time(e, NULL, CLOCK_MONOTONIC,
usec + spawn.timeout, USEC_PER_SEC, on_spawn_timeout, &spawn);
usec + spawn->timeout_usec, USEC_PER_SEC, on_spawn_timeout, spawn);
if (r < 0)
return r;
}
}
r = sd_event_add_child(e, NULL, pid, WEXITED, on_spawn_sigchld, &spawn);
r = sd_event_add_io(e, NULL, spawn->fd_stdout, EPOLLIN, on_spawn_io, spawn);
if (r < 0)
return r;
r = sd_event_add_io(e, NULL, spawn->fd_stderr, EPOLLIN, on_spawn_io, spawn);
if (r < 0)
return r;
r = sd_event_add_child(e, NULL, spawn->pid, WEXITED, on_spawn_sigchld, spawn);
if (r < 0)
return r;
@ -710,16 +580,20 @@ int udev_event_spawn(struct udev_event *event,
char *result, size_t ressize) {
_cleanup_close_pair_ int outpipe[2] = {-1, -1}, errpipe[2] = {-1, -1};
_cleanup_strv_free_ char **argv = NULL;
char **envp = NULL;
Spawn spawn;
pid_t pid;
int r;
assert(result || ressize == 0);
/* pipes from child to parent */
if (!result || log_get_max_level() >= LOG_INFO)
if (pipe2(outpipe, O_NONBLOCK) != 0)
if (result || log_get_max_level() >= LOG_INFO)
if (pipe2(outpipe, O_NONBLOCK|O_CLOEXEC) != 0)
return log_error_errno(errno, "Failed to create pipe for command '%s': %m", cmd);
if (log_get_max_level() >= LOG_INFO)
if (pipe2(errpipe, O_NONBLOCK) != 0)
if (pipe2(errpipe, O_NONBLOCK|O_CLOEXEC) != 0)
return log_error_errno(errno, "Failed to create pipe for command '%s': %m", cmd);
argv = strv_split_full(cmd, NULL, SPLIT_QUOTES|SPLIT_RELAX);
@ -737,36 +611,48 @@ int udev_event_spawn(struct udev_event *event,
free_and_replace(argv[0], program);
}
r = safe_fork("(spawn)", FORK_RESET_SIGNALS|FORK_LOG, &pid);
r = device_get_properties_strv(event->dev->device, &envp);
if (r < 0)
return log_error_errno(r, "Failed to get device properties");
log_debug("Starting '%s'", cmd);
r = safe_fork("(spawn)", FORK_RESET_SIGNALS|FORK_DEATHSIG|FORK_LOG, &pid);
if (r < 0)
return log_error_errno(r, "Failed to fork() to execute command '%s': %m", cmd);
if (r == 0) {
/* child closes parent's ends of pipes */
outpipe[READ_END] = safe_close(outpipe[READ_END]);
errpipe[READ_END] = safe_close(errpipe[READ_END]);
if (rearrange_stdio(-1, outpipe[WRITE_END], errpipe[WRITE_END]) < 0)
_exit(EXIT_FAILURE);
log_debug("Starting '%s'", cmd);
(void) close_all_fds(NULL, 0);
spawn_exec(event, cmd, argv, udev_device_get_properties_envp(event->dev),
outpipe[WRITE_END], errpipe[WRITE_END]);
_exit(2);
execve(argv[0], argv, envp);
_exit(EXIT_FAILURE);
}
/* parent closed child's ends of pipes */
outpipe[WRITE_END] = safe_close(outpipe[WRITE_END]);
errpipe[WRITE_END] = safe_close(errpipe[WRITE_END]);
spawn_read(event,
timeout_usec,
cmd,
outpipe[READ_END], errpipe[READ_END],
result, ressize);
r = spawn_wait(event, timeout_usec, timeout_warn_usec, cmd, pid, accept_failure);
spawn = (Spawn) {
.cmd = cmd,
.pid = pid,
.accept_failure = accept_failure,
.timeout_warn_usec = timeout_warn_usec,
.timeout_usec = timeout_usec,
.event_birth_usec = event->birth_usec,
.fd_stdout = outpipe[READ_END],
.fd_stderr = errpipe[READ_END],
.result = result,
.result_size = ressize,
};
r = spawn_wait(&spawn);
if (r < 0)
return log_error_errno(r, "Failed to wait spawned command '%s': %m", cmd);
if (result)
result[spawn.result_len] = '\0';
return r;
}

3
test/udev-test.pl
View file

@ -1537,13 +1537,14 @@ sub udev_setup {
system("umount", $udev_tmpfs);
rmdir($udev_tmpfs);
mkdir($udev_tmpfs) || die "unable to create udev_tmpfs: $udev_tmpfs\n";
system("mount", "-o", "rw,mode=755,nosuid,noexec,nodev", "-t", "tmpfs", "tmpfs", $udev_tmpfs) && die "unable to mount tmpfs";
system("mount", "-o", "rw,mode=755,nosuid,noexec", "-t", "tmpfs", "tmpfs", $udev_tmpfs) && die "unable to mount tmpfs";
mkdir($udev_dev) || die "unable to create udev_dev: $udev_dev\n";
# setting group and mode of udev_dev ensures the tests work
# even if the parent directory has setgid bit enabled.
chown (0, 0, $udev_dev) || die "unable to chown $udev_dev\n";
chmod (0755, $udev_dev) || die "unable to chmod $udev_dev\n";
system("mknod", $udev_dev . "/null", "c", "1", "3") && "unable to create $udev_dev/null";
system("cp", "-r", "test/sys/", $udev_sys) && die "unable to copy test/sys";