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libudev: run_program() - select() -> epoll

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This commit is contained in:
Kay Sievers
2011-04-18 02:13:40 +02:00
parent 13052c0285
commit 1d843b7d68
1 changed files with 202 additions and 135 deletions
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libudev/libudev-util-private.c
+202 -135
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@@ -19,6 +19,8 @@
#include <ctype.h>
#include <pwd.h>
#include <grp.h>
#include <sys/prctl.h>
#include <sys/epoll.h>
#include <sys/wait.h>
#include <sys/param.h>
@@ -259,6 +261,169 @@ int util_resolve_subsys_kernel(struct udev *udev, const char *string,
return 0;
}
static int run_program_exec(struct udev *udev, int fd_stdout, int fd_stderr,
char *const argv[], char **envp, const sigset_t *sigmask)
{
int err;
int fd;
/* discard child output or connect to pipe */
fd = open("/dev/null", O_RDWR);
if (fd >= 0) {
dup2(fd, STDIN_FILENO);
if (fd_stdout < 0)
dup2(fd, STDOUT_FILENO);
if (fd_stderr < 0)
dup2(fd, STDERR_FILENO);
close(fd);
} else {
err(udev, "open /dev/null failed: %m\n");
}
/* connect pipes to std{out,err} */
if (fd_stdout >= 0) {
dup2(fd_stdout, STDOUT_FILENO);
close(fd_stdout);
}
if (fd_stderr >= 0) {
dup2(fd_stderr, STDERR_FILENO);
close(fd_stderr);
}
/* terminate child in case parent goes away */
prctl(PR_SET_PDEATHSIG, SIGTERM);
/* restore original udev sigmask before exec */
if (sigmask)
sigprocmask(SIG_SETMASK, sigmask, NULL);
execve(argv[0], argv, envp);
/* exec failed */
err = -errno;
if (err == -ENOENT || err == -ENOTDIR) {
/* may be on a filesystem which is not mounted right now */
info(udev, "program '%s' not found\n", argv[0]);
} else {
/* other problems */
err(udev, "exec of program '%s' failed\n", argv[0]);
}
return err;
}
static int run_program_read(struct udev *udev, int fd_stdout, int fd_stderr,
char *const argv[], char *result, size_t ressize, size_t *reslen)
{
size_t respos = 0;
int fd_ep = -1;
struct epoll_event ep_outpipe;
struct epoll_event ep_errpipe;
int err = 0;
/* read from child if requested */
if (fd_stdout < 0 && fd_stderr < 0)
return 0;
fd_ep = epoll_create1(EPOLL_CLOEXEC);
if (fd_ep < 0) {
err = -errno;
err(udev, "error creating epoll fd: %m\n");
goto out;
}
if (fd_stdout >= 0) {
memset(&ep_outpipe, 0, sizeof(struct epoll_event));
ep_outpipe.events = EPOLLIN;
ep_outpipe.data.ptr = &fd_stdout;
if (epoll_ctl(fd_ep, EPOLL_CTL_ADD, fd_stdout, &ep_outpipe) < 0) {
err(udev, "fail to add fd to epoll: %m\n");
goto out;
}
}
if (fd_stderr >= 0) {
memset(&ep_errpipe, 0, sizeof(struct epoll_event));
ep_errpipe.events = EPOLLIN;
ep_errpipe.data.ptr = &fd_stderr;
if (epoll_ctl(fd_ep, EPOLL_CTL_ADD, fd_stderr, &ep_errpipe) < 0) {
err(udev, "fail to add fd to epoll: %m\n");
goto out;
}
}
/* read child output */
while (fd_stdout >= 0 || fd_stderr >= 0) {
int fdcount;
struct epoll_event ev[4];
int i;
fdcount = epoll_wait(fd_ep, ev, ARRAY_SIZE(ev), -1);
if (fdcount < 0) {
if (errno == EINTR)
continue;
err(udev, "failed to poll: %m\n");
err = -errno;
goto out;
}
for (i = 0; i < fdcount; i++) {
int *fd = (int *)ev[i].data.ptr;
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 {
err(udev, "ressize %zd too short\n", ressize);
err = -ENOBUFS;
}
}
/* 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')
info(udev, "'%s'(%s) '%s'\n", argv[0], *fd == fd_stdout ? "out" : "err" , line);
}
}
} else if (ev[i].events & EPOLLHUP) {
if (epoll_ctl(fd_ep, EPOLL_CTL_DEL, *fd, NULL) < 0) {
err = -errno;
err(udev, "failed to remove fd from epoll: %m\n");
goto out;
}
*fd = -1;
}
}
}
/* return the child's stdout string */
if (result != NULL) {
result[respos] = '\0';
dbg(udev, "result='%s'\n", result);
if (reslen != NULL)
*reslen = respos;
}
out:
if (fd_ep >= 0)
close(fd_ep);
return err;
}
int util_run_program(struct udev *udev, const char *command, char **envp,
char *result, size_t ressize, size_t *reslen,
const sigset_t *sigmask)
@@ -270,7 +435,6 @@ int util_run_program(struct udev *udev, const char *command, char **envp,
char arg[UTIL_PATH_SIZE];
char program[UTIL_PATH_SIZE];
char *argv[((sizeof(arg) + 1) / 2) + 1];
int devnull;
int i;
int err = 0;
@@ -305,17 +469,19 @@ int util_run_program(struct udev *udev, const char *command, char **envp,
argv[1] = NULL;
}
/* prepare pipes from child to parent */
/* pipes from child to parent */
if (result != NULL || udev_get_log_priority(udev) >= LOG_INFO) {
if (pipe(outpipe) != 0) {
if (pipe2(outpipe, O_NONBLOCK) != 0) {
err = -errno;
err(udev, "pipe failed: %m\n");
return -1;
goto out;
}
}
if (udev_get_log_priority(udev) >= LOG_INFO) {
if (pipe(errpipe) != 0) {
if (pipe2(errpipe, O_NONBLOCK) != 0) {
err = -errno;
err(udev, "pipe failed: %m\n");
return -1;
goto out;
}
}
@@ -328,145 +494,36 @@ int util_run_program(struct udev *udev, const char *command, char **envp,
pid = fork();
switch(pid) {
case 0:
/* child closes parent ends of pipes */
if (outpipe[READ_END] > 0)
/* child closes parent's ends of pipes */
if (outpipe[READ_END] >= 0) {
close(outpipe[READ_END]);
if (errpipe[READ_END] > 0)
outpipe[READ_END] = -1;
}
if (errpipe[READ_END] >= 0) {
close(errpipe[READ_END]);
/* discard child output or connect to pipe */
devnull = open("/dev/null", O_RDWR);
if (devnull > 0) {
dup2(devnull, STDIN_FILENO);
if (outpipe[WRITE_END] < 0)
dup2(devnull, STDOUT_FILENO);
if (errpipe[WRITE_END] < 0)
dup2(devnull, STDERR_FILENO);
close(devnull);
} else
err(udev, "open /dev/null failed: %m\n");
if (outpipe[WRITE_END] > 0) {
dup2(outpipe[WRITE_END], STDOUT_FILENO);
close(outpipe[WRITE_END]);
}
if (errpipe[WRITE_END] > 0) {
dup2(errpipe[WRITE_END], STDERR_FILENO);
close(errpipe[WRITE_END]);
errpipe[READ_END] = -1;
}
if (sigmask)
sigprocmask(SIG_SETMASK, sigmask, NULL);
err = run_program_exec(udev, outpipe[WRITE_END], errpipe[WRITE_END], argv, envp, sigmask);
execve(argv[0], argv, envp);
if (errno == ENOENT || errno == ENOTDIR) {
/* may be on a filesystem which is not mounted right now */
info(udev, "program '%s' not found\n", argv[0]);
} else {
/* other problems */
err(udev, "exec of program '%s' failed\n", argv[0]);
}
_exit(1);
case -1:
err(udev, "fork of '%s' failed: %m\n", argv[0]);
return -1;
err = -1;
goto out;
default:
/* read from child if requested */
if (outpipe[READ_END] > 0 || errpipe[READ_END] > 0) {
ssize_t count;
size_t respos = 0;
/* parent closes child ends of pipes */
if (outpipe[WRITE_END] > 0)
close(outpipe[WRITE_END]);
if (errpipe[WRITE_END] > 0)
close(errpipe[WRITE_END]);
/* read child output */
while (outpipe[READ_END] > 0 || errpipe[READ_END] > 0) {
int fdcount;
fd_set readfds;
FD_ZERO(&readfds);
if (outpipe[READ_END] > 0)
FD_SET(outpipe[READ_END], &readfds);
if (errpipe[READ_END] > 0)
FD_SET(errpipe[READ_END], &readfds);
fdcount = select(MAX(outpipe[READ_END], errpipe[READ_END])+1, &readfds, NULL, NULL, NULL);
if (fdcount < 0) {
if (errno == EINTR)
continue;
err = -1;
break;
}
/* get stdout */
if (outpipe[READ_END] > 0 && FD_ISSET(outpipe[READ_END], &readfds)) {
char inbuf[1024];
char *pos;
char *line;
count = read(outpipe[READ_END], inbuf, sizeof(inbuf)-1);
if (count <= 0) {
close(outpipe[READ_END]);
outpipe[READ_END] = -1;
if (count < 0) {
err(udev, "stdin read failed: %m\n");
err = -1;
}
continue;
}
inbuf[count] = '\0';
/* store result for rule processing */
if (result) {
if (respos + count < ressize) {
memcpy(&result[respos], inbuf, count);
respos += count;
} else {
err(udev, "ressize %ld too short\n", (long)ressize);
err = -1;
}
}
pos = inbuf;
while ((line = strsep(&pos, "\n")))
if (pos || line[0] != '\0')
info(udev, "'%s' (stdout) '%s'\n", argv[0], line);
}
/* get stderr */
if (errpipe[READ_END] > 0 && FD_ISSET(errpipe[READ_END], &readfds)) {
char errbuf[1024];
char *pos;
char *line;
count = read(errpipe[READ_END], errbuf, sizeof(errbuf)-1);
if (count <= 0) {
close(errpipe[READ_END]);
errpipe[READ_END] = -1;
if (count < 0)
err(udev, "stderr read failed: %m\n");
continue;
}
errbuf[count] = '\0';
pos = errbuf;
while ((line = strsep(&pos, "\n")))
if (pos || line[0] != '\0')
info(udev, "'%s' (stderr) '%s'\n", argv[0], line);
}
}
if (outpipe[READ_END] > 0)
close(outpipe[READ_END]);
if (errpipe[READ_END] > 0)
close(errpipe[READ_END]);
/* return the child's stdout string */
if (result) {
result[respos] = '\0';
dbg(udev, "result='%s'\n", result);
if (reslen)
*reslen = respos;
}
/* parent closed child's ends of pipes */
if (outpipe[WRITE_END] >= 0) {
close(outpipe[WRITE_END]);
outpipe[WRITE_END] = -1;
}
if (errpipe[WRITE_END] >= 0) {
close(errpipe[WRITE_END]);
errpipe[WRITE_END] = -1;
}
err = run_program_read(udev, outpipe[READ_END], errpipe[READ_END], argv, result, ressize, reslen);
waitpid(pid, &status, 0);
if (WIFEXITED(status)) {
info(udev, "'%s' returned with exitcode %i\n", command, WEXITSTATUS(status));
@@ -477,5 +534,15 @@ int util_run_program(struct udev *udev, const char *command, char **envp,
err = -1;
}
}
out:
if (outpipe[READ_END] >= 0)
close(outpipe[READ_END]);
if (outpipe[WRITE_END] >= 0)
close(outpipe[WRITE_END]);
if (errpipe[READ_END] >= 0)
close(errpipe[READ_END]);
if (errpipe[WRITE_END] >= 0)
close(errpipe[WRITE_END]);
return err;
}