/* Calls fork() and on success returns its return value. On failure, logs an
* error and exits unsuccessfully.
*
* Post-fork, but before returning, this function calls a few other functions
* that are generally useful if the child isn't planning to exec a new
* process. */
static pid_t
fork_and_clean_up(void)
{
pid_t pid = xfork();
if (pid > 0) {
/* Running in parent process. */
fatal_signal_fork();
} else if (!pid) {
/* Running in child process. */
lockfile_postfork();
}
return pid;
}
static pid_t
fork_and_wait_for_startup(int *fdp)
{
int fds[2];
pid_t pid;
if (pipe(fds) < 0) {
ovs_fatal(errno, "pipe failed");
}
pid = fork();
if (pid > 0) {
/* Running in parent process. */
char c;
close(fds[1]);
fatal_signal_fork();
if (read(fds[0], &c, 1) != 1) {
int retval;
int status;
do {
retval = waitpid(pid, &status, 0);
} while (retval == -1 && errno == EINTR);
if (retval == pid
&& WIFEXITED(status)
&& WEXITSTATUS(status)) {
/* Child exited with an error. Convey the same error to
* our parent process as a courtesy. */
exit(WEXITSTATUS(status));
}
ovs_fatal(errno, "fork child failed to signal startup");
}
close(fds[0]);
*fdp = -1;
} else if (!pid) {
/* Running in child process. */
close(fds[0]);
time_postfork();
lockfile_postfork();
*fdp = fds[1];
} else {
ovs_fatal(errno, "could not fork");
}
return pid;
}
static pid_t
fork_and_wait_for_startup(int *fdp)
{
int fds[2];
pid_t pid;
xpipe(fds);
pid = fork();
if (pid > 0) {
/* Running in parent process. */
size_t bytes_read;
char c;
close(fds[1]);
fatal_signal_fork();
if (read_fully(fds[0], &c, 1, &bytes_read) != 0) {
int retval;
int status;
do {
retval = waitpid(pid, &status, 0);
} while (retval == -1 && errno == EINTR);
if (retval == pid
&& WIFEXITED(status)
&& WEXITSTATUS(status)) {
/* Child exited with an error. Convey the same error to
* our parent process as a courtesy. */
exit(WEXITSTATUS(status));
}
VLOG_FATAL("fork child failed to signal startup (%s)",
strerror(errno));
}
close(fds[0]);
*fdp = -1;
} else if (!pid) {
/* Running in child process. */
close(fds[0]);
time_postfork();
lockfile_postfork();
*fdp = fds[1];
} else {
VLOG_FATAL("fork failed (%s)", strerror(errno));
}
return pid;
}
static enum { PARENT, CHILD }
do_fork(void)
{
switch (fork()) {
case 0:
lockfile_postfork();
return CHILD;
default:
return PARENT;
case -1:
/* Error. */
ovs_fatal(errno, "fork failed");
}
}
/* Calls fork() and on success returns its return value. On failure, logs an
* error and exits unsuccessfully.
*
* Post-fork, but before returning, this function calls a few other functions
* that are generally useful if the child isn't planning to exec a new
* process. */
pid_t
fork_and_clean_up(void)
{
pid_t pid;
pid = fork();
if (pid > 0) {
/* Running in parent process. */
fatal_signal_fork();
} else if (!pid) {
/* Running in child process. */
time_postfork();
lockfile_postfork();
} else {
VLOG_FATAL("fork failed (%s)", strerror(errno));
}
return pid;
}