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27463101f1
Be more friendly when signalfd() fails, and also add configure checks to detect that syscall(SYS_signalfd) actually works. malc pointed out that some installs do not have /usr/include/linux headers that are in sync with the glibc headers so why SYS_signalfd is defined, it's #defined to _NR_signalfd which is not defined in the /usr/include/linux header. While this is a distro bug, it doesn't hurt to do a more thorough job in detection. Signed-off-by: Anthony Liguori <aliguori@us.ibm.com> git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@5334 c046a42c-6fe2-441c-8c8c-71466251a162
128 lines
2.4 KiB
C
128 lines
2.4 KiB
C
/*
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* signalfd/eventfd compatibility
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*
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* Copyright IBM, Corp. 2008
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*
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* Authors:
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* Anthony Liguori <aliguori@us.ibm.com>
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*
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* This work is licensed under the terms of the GNU GPL, version 2. See
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* the COPYING file in the top-level directory.
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*
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*/
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#include "qemu-common.h"
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#include "compatfd.h"
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#include <sys/syscall.h>
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#include <pthread.h>
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struct sigfd_compat_info
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{
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sigset_t mask;
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int fd;
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};
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static void *sigwait_compat(void *opaque)
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{
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struct sigfd_compat_info *info = opaque;
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int err;
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sigset_t all;
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sigfillset(&all);
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sigprocmask(SIG_BLOCK, &all, NULL);
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do {
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siginfo_t siginfo;
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err = sigwaitinfo(&info->mask, &siginfo);
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if (err == -1 && errno == EINTR) {
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err = 0;
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continue;
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}
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if (err > 0) {
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char buffer[128];
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size_t offset = 0;
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memcpy(buffer, &err, sizeof(err));
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while (offset < sizeof(buffer)) {
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ssize_t len;
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len = write(info->fd, buffer + offset,
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sizeof(buffer) - offset);
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if (len == -1 && errno == EINTR)
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continue;
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if (len <= 0) {
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err = -1;
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break;
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}
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offset += len;
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}
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}
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} while (err >= 0);
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return NULL;
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}
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static int qemu_signalfd_compat(const sigset_t *mask)
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{
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pthread_attr_t attr;
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pthread_t tid;
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struct sigfd_compat_info *info;
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int fds[2];
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info = malloc(sizeof(*info));
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if (info == NULL) {
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errno = ENOMEM;
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return -1;
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}
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if (pipe(fds) == -1) {
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free(info);
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return -1;
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}
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memcpy(&info->mask, mask, sizeof(*mask));
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info->fd = fds[1];
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pthread_attr_init(&attr);
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pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
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pthread_create(&tid, &attr, sigwait_compat, info);
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pthread_attr_destroy(&attr);
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return fds[0];
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}
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int qemu_signalfd(const sigset_t *mask)
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{
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#if defined(CONFIG_signalfd)
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int ret;
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ret = syscall(SYS_signalfd, -1, mask, _NSIG / 8);
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if (ret != -1)
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return ret;
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#endif
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return qemu_signalfd_compat(mask);
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}
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int qemu_eventfd(int *fds)
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{
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#if defined(CONFIG_eventfd)
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int ret;
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ret = syscall(SYS_eventfd, 0);
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if (ret >= 0) {
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fds[0] = fds[1] = ret;
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return 0;
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}
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#endif
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return pipe(fds);
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}
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