From 077ee50d7f385a79a6d8f06ff35b170d207993cf Mon Sep 17 00:00:00 2001 From: Marcelo Tosatti Date: Mon, 11 Oct 2010 15:31:15 -0300 Subject: [PATCH] signalfd compatibility Port qemu-kvm's signalfd compat code. commit 5a7fdd0abd7cd24dac205317a4195446ab8748b5 Author: Anthony Liguori Date: Wed May 7 11:55:47 2008 -0500 Use signalfd() in io-thread This patch reworks the IO thread to use signalfd() instead of sigtimedwait() This will eliminate the need to use SIGIO everywhere. Signed-off-by: Marcelo Tosatti Signed-off-by: Avi Kivity --- Makefile.objs | 1 + compatfd.c | 117 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ compatfd.h | 43 +++++++++++++++++++++ configure | 18 +++++++++ 4 files changed, 179 insertions(+) create mode 100644 compatfd.c create mode 100644 compatfd.h diff --git a/Makefile.objs b/Makefile.objs index cd5a24b..6e6f60a 100644 --- a/Makefile.objs +++ b/Makefile.objs @@ -125,6 +125,7 @@ common-obj-y += $(addprefix ui/, $(ui-obj-y)) common-obj-y += iov.o acl.o common-obj-$(CONFIG_THREAD) += qemu-thread.o +common-obj-$(CONFIG_IOTHREAD) += compatfd.o common-obj-y += notify.o event_notifier.o common-obj-y += qemu-timer.o diff --git a/compatfd.c b/compatfd.c new file mode 100644 index 0000000..a7cebc4 --- /dev/null +++ b/compatfd.c @@ -0,0 +1,117 @@ +/* + * signalfd/eventfd compatibility + * + * Copyright IBM, Corp. 2008 + * + * Authors: + * Anthony Liguori + * + * This work is licensed under the terms of the GNU GPL, version 2. See + * the COPYING file in the top-level directory. + * + */ + +#include "qemu-common.h" +#include "compatfd.h" + +#include +#include + +struct sigfd_compat_info +{ + sigset_t mask; + int fd; +}; + +static void *sigwait_compat(void *opaque) +{ + struct sigfd_compat_info *info = opaque; + int err; + sigset_t all; + + sigfillset(&all); + sigprocmask(SIG_BLOCK, &all, NULL); + + do { + siginfo_t siginfo; + + err = sigwaitinfo(&info->mask, &siginfo); + if (err == -1 && errno == EINTR) { + err = 0; + continue; + } + + if (err > 0) { + char buffer[128]; + size_t offset = 0; + + memcpy(buffer, &err, sizeof(err)); + while (offset < sizeof(buffer)) { + ssize_t len; + + len = write(info->fd, buffer + offset, + sizeof(buffer) - offset); + if (len == -1 && errno == EINTR) + continue; + + if (len <= 0) { + err = -1; + break; + } + + offset += len; + } + } + } while (err >= 0); + + return NULL; +} + +static int qemu_signalfd_compat(const sigset_t *mask) +{ + pthread_attr_t attr; + pthread_t tid; + struct sigfd_compat_info *info; + int fds[2]; + + info = malloc(sizeof(*info)); + if (info == NULL) { + errno = ENOMEM; + return -1; + } + + if (pipe(fds) == -1) { + free(info); + return -1; + } + + qemu_set_cloexec(fds[0]); + qemu_set_cloexec(fds[1]); + + memcpy(&info->mask, mask, sizeof(*mask)); + info->fd = fds[1]; + + pthread_attr_init(&attr); + pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED); + + pthread_create(&tid, &attr, sigwait_compat, info); + + pthread_attr_destroy(&attr); + + return fds[0]; +} + +int qemu_signalfd(const sigset_t *mask) +{ +#if defined(CONFIG_SIGNALFD) + int ret; + + ret = syscall(SYS_signalfd, -1, mask, _NSIG / 8); + if (ret != -1) { + qemu_set_cloexec(ret); + return ret; + } +#endif + + return qemu_signalfd_compat(mask); +} diff --git a/compatfd.h b/compatfd.h new file mode 100644 index 0000000..fc37915 --- /dev/null +++ b/compatfd.h @@ -0,0 +1,43 @@ +/* + * signalfd/eventfd compatibility + * + * Copyright IBM, Corp. 2008 + * + * Authors: + * Anthony Liguori + * + * This work is licensed under the terms of the GNU GPL, version 2. See + * the COPYING file in the top-level directory. + * + */ + +#ifndef QEMU_COMPATFD_H +#define QEMU_COMPATFD_H + +#include + +struct qemu_signalfd_siginfo { + uint32_t ssi_signo; /* Signal number */ + int32_t ssi_errno; /* Error number (unused) */ + int32_t ssi_code; /* Signal code */ + uint32_t ssi_pid; /* PID of sender */ + uint32_t ssi_uid; /* Real UID of sender */ + int32_t ssi_fd; /* File descriptor (SIGIO) */ + uint32_t ssi_tid; /* Kernel timer ID (POSIX timers) */ + uint32_t ssi_band; /* Band event (SIGIO) */ + uint32_t ssi_overrun; /* POSIX timer overrun count */ + uint32_t ssi_trapno; /* Trap number that caused signal */ + int32_t ssi_status; /* Exit status or signal (SIGCHLD) */ + int32_t ssi_int; /* Integer sent by sigqueue(2) */ + uint64_t ssi_ptr; /* Pointer sent by sigqueue(2) */ + uint64_t ssi_utime; /* User CPU time consumed (SIGCHLD) */ + uint64_t ssi_stime; /* System CPU time consumed (SIGCHLD) */ + uint64_t ssi_addr; /* Address that generated signal + (for hardware-generated signals) */ + uint8_t pad[48]; /* Pad size to 128 bytes (allow for + additional fields in the future) */ +}; + +int qemu_signalfd(const sigset_t *mask); + +#endif diff --git a/configure b/configure index 5f4d718..9ed05de 100755 --- a/configure +++ b/configure @@ -1957,6 +1957,21 @@ if compile_prog "" "" ; then splice=yes fi +########################################## +# signalfd probe +signalfd="no" +cat > $TMPC << EOF +#define _GNU_SOURCE +#include +#include +#include +int main(void) { return syscall(SYS_signalfd, -1, NULL, _NSIG / 8); } +EOF + +if compile_prog "" "" ; then + signalfd=yes +fi + # check if eventfd is supported eventfd=no cat > $TMPC << EOF @@ -2559,6 +2574,9 @@ fi if test "$fdt" = "yes" ; then echo "CONFIG_FDT=y" >> $config_host_mak fi +if test "$signalfd" = "yes" ; then + echo "CONFIG_SIGNALFD=y" >> $config_host_mak +fi if test "$need_offsetof" = "yes" ; then echo "CONFIG_NEED_OFFSETOF=y" >> $config_host_mak fi -- 2.7.4