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util: drop qemu_fork()

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Fortunately, qemu_fork() is no longer used since commit
a95570e3e4 ("io/command: use glib GSpawn, instead of open-coding
fork/exec"). (GSpawn uses posix_spawn() whenever possible instead)

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Message-Id: <20230221124802.4103554-2-marcandre.lureau@redhat.com>
This commit is contained in:
Marc-André Lureau 2023-02-21 16:47:46 +04:00
parent 29c8a9e31a
commit 8278e30c45
3 changed files with 0 additions and 93 deletions
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14
include/qemu/osdep.h
View file

@ -665,20 +665,6 @@ void qemu_prealloc_mem(int fd, char *area, size_t sz, int max_threads,
*/
char *qemu_get_pid_name(pid_t pid);
/**
* qemu_fork:
*
* A version of fork that avoids signal handler race
* conditions that can lead to child process getting
* signals that are otherwise only expected by the
* parent. It also resets all signal handlers to the
* default settings.
*
* Returns 0 to child process, pid number to parent
* or -1 on failure.
*/
pid_t qemu_fork(Error **errp);
/* Using intptr_t ensures that qemu_*_page_mask is sign-extended even
* when intptr_t is 32-bit and we are aligning a long long.
*/

70
util/oslib-posix.c
View file

@ -583,76 +583,6 @@ char *qemu_get_pid_name(pid_t pid)
}
pid_t qemu_fork(Error **errp)
{
sigset_t oldmask, newmask;
struct sigaction sig_action;
int saved_errno;
pid_t pid;
/*
* 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) {
error_setg_errno(errp, errno,
"cannot block signals");
return -1;
}
pid = fork();
saved_errno = errno;
if (pid < 0) {
/* attempt to restore signal mask, but ignore failure, to
* avoid obscuring the fork failure */
(void)pthread_sigmask(SIG_SETMASK, &oldmask, NULL);
error_setg_errno(errp, saved_errno,
"cannot fork child process");
errno = saved_errno;
return -1;
} else if (pid) {
/* parent process */
/* Restore our original signal mask now that the child is
* safely running. Only documented failures are EFAULT (not
* possible, since we are using just-grabbed mask) or EINVAL
* (not possible, since we are using correct arguments). */
(void)pthread_sigmask(SIG_SETMASK, &oldmask, NULL);
} else {
/* child process */
size_t i;
/* 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
* won't happen, the latter we expect, so no need to check
* return value */
(void)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) {
Error *local_err = NULL;
error_setg_errno(&local_err, errno,
"cannot unblock signals");
error_report_err(local_err);
_exit(1);
}
}
return pid;
}
void *qemu_alloc_stack(size_t *sz)
{
void *ptr, *guardpage;

9
util/oslib-win32.c
View file

@ -283,15 +283,6 @@ char *qemu_get_pid_name(pid_t pid)
}
pid_t qemu_fork(Error **errp)
{
errno = ENOSYS;
error_setg_errno(errp, errno,
"cannot fork child process");
return -1;
}
#undef connect
int qemu_connect_wrap(int sockfd, const struct sockaddr *addr,
socklen_t addrlen)