618 lines
16 KiB
C
618 lines
16 KiB
C
/*
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* os-posix-lib.c
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*
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* Copyright (c) 2003-2008 Fabrice Bellard
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* Copyright (c) 2010 Red Hat, Inc.
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*
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* QEMU library functions on POSIX which are shared between QEMU and
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* the QEMU tools.
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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#include "qemu/osdep.h"
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#include <termios.h>
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#include <glib/gprintf.h>
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#include "sysemu/sysemu.h"
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#include "trace.h"
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#include "qapi/error.h"
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#include "qemu/sockets.h"
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#include <libgen.h>
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#include <sys/signal.h>
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#include "qemu/cutils.h"
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#ifdef CONFIG_LINUX
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#include <sys/syscall.h>
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#endif
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#ifdef __FreeBSD__
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#include <sys/sysctl.h>
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#include <sys/user.h>
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#include <libutil.h>
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#endif
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#include "qemu/mmap-alloc.h"
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#ifdef CONFIG_DEBUG_STACK_USAGE
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#include "qemu/error-report.h"
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#endif
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#define MAX_MEM_PREALLOC_THREAD_COUNT 16
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struct MemsetThread {
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char *addr;
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uint64_t numpages;
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uint64_t hpagesize;
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QemuThread pgthread;
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sigjmp_buf env;
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};
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typedef struct MemsetThread MemsetThread;
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static MemsetThread *memset_thread;
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static int memset_num_threads;
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static bool memset_thread_failed;
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int qemu_get_thread_id(void)
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{
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#if defined(__linux__)
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return syscall(SYS_gettid);
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#else
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return getpid();
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#endif
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}
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int qemu_daemon(int nochdir, int noclose)
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{
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return daemon(nochdir, noclose);
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}
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void *qemu_oom_check(void *ptr)
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{
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if (ptr == NULL) {
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fprintf(stderr, "Failed to allocate memory: %s\n", strerror(errno));
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abort();
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}
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return ptr;
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}
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void *qemu_try_memalign(size_t alignment, size_t size)
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{
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void *ptr;
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if (alignment < sizeof(void*)) {
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alignment = sizeof(void*);
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}
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#if defined(_POSIX_C_SOURCE) && !defined(__sun__)
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int ret;
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ret = posix_memalign(&ptr, alignment, size);
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if (ret != 0) {
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errno = ret;
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ptr = NULL;
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}
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#elif defined(CONFIG_BSD)
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ptr = valloc(size);
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#else
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ptr = memalign(alignment, size);
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#endif
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trace_qemu_memalign(alignment, size, ptr);
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return ptr;
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}
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void *qemu_memalign(size_t alignment, size_t size)
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{
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return qemu_oom_check(qemu_try_memalign(alignment, size));
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}
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/* alloc shared memory pages */
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void *qemu_anon_ram_alloc(size_t size, uint64_t *alignment)
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{
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size_t align = QEMU_VMALLOC_ALIGN;
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void *ptr = qemu_ram_mmap(-1, size, align, false);
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if (ptr == MAP_FAILED) {
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return NULL;
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}
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if (alignment) {
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*alignment = align;
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}
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trace_qemu_anon_ram_alloc(size, ptr);
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return ptr;
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}
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void qemu_vfree(void *ptr)
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{
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trace_qemu_vfree(ptr);
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free(ptr);
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}
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void qemu_anon_ram_free(void *ptr, size_t size)
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{
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trace_qemu_anon_ram_free(ptr, size);
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qemu_ram_munmap(ptr, size);
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}
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void qemu_set_block(int fd)
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{
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int f;
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f = fcntl(fd, F_GETFL);
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fcntl(fd, F_SETFL, f & ~O_NONBLOCK);
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}
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void qemu_set_nonblock(int fd)
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{
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int f;
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f = fcntl(fd, F_GETFL);
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fcntl(fd, F_SETFL, f | O_NONBLOCK);
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}
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int socket_set_fast_reuse(int fd)
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{
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int val = 1, ret;
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ret = setsockopt(fd, SOL_SOCKET, SO_REUSEADDR,
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(const char *)&val, sizeof(val));
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assert(ret == 0);
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return ret;
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}
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void qemu_set_cloexec(int fd)
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{
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int f;
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f = fcntl(fd, F_GETFD);
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assert(f != -1);
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f = fcntl(fd, F_SETFD, f | FD_CLOEXEC);
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assert(f != -1);
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}
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/*
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* Creates a pipe with FD_CLOEXEC set on both file descriptors
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*/
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int qemu_pipe(int pipefd[2])
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{
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int ret;
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#ifdef CONFIG_PIPE2
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ret = pipe2(pipefd, O_CLOEXEC);
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if (ret != -1 || errno != ENOSYS) {
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return ret;
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}
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#endif
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ret = pipe(pipefd);
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if (ret == 0) {
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qemu_set_cloexec(pipefd[0]);
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qemu_set_cloexec(pipefd[1]);
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}
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return ret;
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}
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char *
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qemu_get_local_state_pathname(const char *relative_pathname)
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{
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return g_strdup_printf("%s/%s", CONFIG_QEMU_LOCALSTATEDIR,
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relative_pathname);
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}
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void qemu_set_tty_echo(int fd, bool echo)
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{
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struct termios tty;
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tcgetattr(fd, &tty);
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if (echo) {
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tty.c_lflag |= ECHO | ECHONL | ICANON | IEXTEN;
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} else {
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tty.c_lflag &= ~(ECHO | ECHONL | ICANON | IEXTEN);
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}
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tcsetattr(fd, TCSANOW, &tty);
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}
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static char exec_dir[PATH_MAX];
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void qemu_init_exec_dir(const char *argv0)
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{
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char *dir;
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char *p = NULL;
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char buf[PATH_MAX];
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assert(!exec_dir[0]);
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#if defined(__linux__)
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{
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int len;
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len = readlink("/proc/self/exe", buf, sizeof(buf) - 1);
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if (len > 0) {
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buf[len] = 0;
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p = buf;
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}
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}
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#elif defined(__FreeBSD__)
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{
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static int mib[4] = {CTL_KERN, KERN_PROC, KERN_PROC_PATHNAME, -1};
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size_t len = sizeof(buf) - 1;
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*buf = '\0';
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if (!sysctl(mib, ARRAY_SIZE(mib), buf, &len, NULL, 0) &&
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*buf) {
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buf[sizeof(buf) - 1] = '\0';
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p = buf;
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}
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}
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#endif
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/* If we don't have any way of figuring out the actual executable
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location then try argv[0]. */
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if (!p) {
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if (!argv0) {
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return;
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}
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p = realpath(argv0, buf);
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if (!p) {
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return;
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}
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}
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dir = g_path_get_dirname(p);
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pstrcpy(exec_dir, sizeof(exec_dir), dir);
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g_free(dir);
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}
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char *qemu_get_exec_dir(void)
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{
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return g_strdup(exec_dir);
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}
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static void sigbus_handler(int signal)
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{
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int i;
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if (memset_thread) {
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for (i = 0; i < memset_num_threads; i++) {
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if (qemu_thread_is_self(&memset_thread[i].pgthread)) {
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siglongjmp(memset_thread[i].env, 1);
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}
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}
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}
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}
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static void *do_touch_pages(void *arg)
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{
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MemsetThread *memset_args = (MemsetThread *)arg;
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char *addr = memset_args->addr;
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uint64_t numpages = memset_args->numpages;
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uint64_t hpagesize = memset_args->hpagesize;
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sigset_t set, oldset;
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int i = 0;
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/* unblock SIGBUS */
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sigemptyset(&set);
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sigaddset(&set, SIGBUS);
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pthread_sigmask(SIG_UNBLOCK, &set, &oldset);
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if (sigsetjmp(memset_args->env, 1)) {
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memset_thread_failed = true;
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} else {
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for (i = 0; i < numpages; i++) {
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/*
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* Read & write back the same value, so we don't
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* corrupt existing user/app data that might be
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* stored.
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*
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* 'volatile' to stop compiler optimizing this away
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* to a no-op
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*
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* TODO: get a better solution from kernel so we
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* don't need to write at all so we don't cause
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* wear on the storage backing the region...
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*/
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*(volatile char *)addr = *addr;
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addr += hpagesize;
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}
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}
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pthread_sigmask(SIG_SETMASK, &oldset, NULL);
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return NULL;
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}
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static inline int get_memset_num_threads(int smp_cpus)
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{
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long host_procs = sysconf(_SC_NPROCESSORS_ONLN);
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int ret = 1;
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if (host_procs > 0) {
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ret = MIN(MIN(host_procs, MAX_MEM_PREALLOC_THREAD_COUNT), smp_cpus);
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}
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/* In case sysconf() fails, we fall back to single threaded */
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return ret;
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}
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static bool touch_all_pages(char *area, size_t hpagesize, size_t numpages,
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int smp_cpus)
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{
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uint64_t numpages_per_thread, size_per_thread;
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char *addr = area;
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int i = 0;
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memset_thread_failed = false;
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memset_num_threads = get_memset_num_threads(smp_cpus);
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memset_thread = g_new0(MemsetThread, memset_num_threads);
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numpages_per_thread = (numpages / memset_num_threads);
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size_per_thread = (hpagesize * numpages_per_thread);
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for (i = 0; i < memset_num_threads; i++) {
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memset_thread[i].addr = addr;
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memset_thread[i].numpages = (i == (memset_num_threads - 1)) ?
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numpages : numpages_per_thread;
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memset_thread[i].hpagesize = hpagesize;
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qemu_thread_create(&memset_thread[i].pgthread, "touch_pages",
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do_touch_pages, &memset_thread[i],
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QEMU_THREAD_JOINABLE);
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addr += size_per_thread;
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numpages -= numpages_per_thread;
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}
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for (i = 0; i < memset_num_threads; i++) {
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qemu_thread_join(&memset_thread[i].pgthread);
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}
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g_free(memset_thread);
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memset_thread = NULL;
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return memset_thread_failed;
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}
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void os_mem_prealloc(int fd, char *area, size_t memory, int smp_cpus,
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Error **errp)
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{
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int ret;
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struct sigaction act, oldact;
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size_t hpagesize = qemu_fd_getpagesize(fd);
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size_t numpages = DIV_ROUND_UP(memory, hpagesize);
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memset(&act, 0, sizeof(act));
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act.sa_handler = &sigbus_handler;
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act.sa_flags = 0;
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ret = sigaction(SIGBUS, &act, &oldact);
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if (ret) {
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error_setg_errno(errp, errno,
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"os_mem_prealloc: failed to install signal handler");
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return;
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}
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/* touch pages simultaneously */
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if (touch_all_pages(area, hpagesize, numpages, smp_cpus)) {
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error_setg(errp, "os_mem_prealloc: Insufficient free host memory "
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"pages available to allocate guest RAM");
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}
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ret = sigaction(SIGBUS, &oldact, NULL);
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if (ret) {
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/* Terminate QEMU since it can't recover from error */
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perror("os_mem_prealloc: failed to reinstall signal handler");
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exit(1);
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}
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}
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char *qemu_get_pid_name(pid_t pid)
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{
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char *name = NULL;
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#if defined(__FreeBSD__)
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/* BSDs don't have /proc, but they provide a nice substitute */
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struct kinfo_proc *proc = kinfo_getproc(pid);
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if (proc) {
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name = g_strdup(proc->ki_comm);
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free(proc);
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}
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#else
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/* Assume a system with reasonable procfs */
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char *pid_path;
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size_t len;
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pid_path = g_strdup_printf("/proc/%d/cmdline", pid);
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g_file_get_contents(pid_path, &name, &len, NULL);
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g_free(pid_path);
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#endif
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return name;
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}
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pid_t qemu_fork(Error **errp)
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{
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sigset_t oldmask, newmask;
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struct sigaction sig_action;
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int saved_errno;
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pid_t pid;
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/*
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* Need to block signals now, so that child process can safely
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* kill off caller's signal handlers without a race.
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*/
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sigfillset(&newmask);
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if (pthread_sigmask(SIG_SETMASK, &newmask, &oldmask) != 0) {
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error_setg_errno(errp, errno,
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"cannot block signals");
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return -1;
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}
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pid = fork();
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saved_errno = errno;
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if (pid < 0) {
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/* attempt to restore signal mask, but ignore failure, to
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* avoid obscuring the fork failure */
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(void)pthread_sigmask(SIG_SETMASK, &oldmask, NULL);
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error_setg_errno(errp, saved_errno,
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"cannot fork child process");
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errno = saved_errno;
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return -1;
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} else if (pid) {
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/* parent process */
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/* Restore our original signal mask now that the child is
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* safely running. Only documented failures are EFAULT (not
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* possible, since we are using just-grabbed mask) or EINVAL
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* (not possible, since we are using correct arguments). */
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(void)pthread_sigmask(SIG_SETMASK, &oldmask, NULL);
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} else {
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/* child process */
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size_t i;
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/* Clear out all signal handlers from parent so nothing
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* unexpected can happen in our child once we unblock
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* signals */
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sig_action.sa_handler = SIG_DFL;
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sig_action.sa_flags = 0;
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sigemptyset(&sig_action.sa_mask);
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for (i = 1; i < NSIG; i++) {
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/* Only possible errors are EFAULT or EINVAL The former
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* won't happen, the latter we expect, so no need to check
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* return value */
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(void)sigaction(i, &sig_action, NULL);
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}
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/* Unmask all signals in child, since we've no idea what the
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* caller's done with their signal mask and don't want to
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* propagate that to children */
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sigemptyset(&newmask);
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if (pthread_sigmask(SIG_SETMASK, &newmask, NULL) != 0) {
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Error *local_err = NULL;
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error_setg_errno(&local_err, errno,
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"cannot unblock signals");
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error_report_err(local_err);
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_exit(1);
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}
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}
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return pid;
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}
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void *qemu_alloc_stack(size_t *sz)
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{
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void *ptr, *guardpage;
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#ifdef CONFIG_DEBUG_STACK_USAGE
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void *ptr2;
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#endif
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size_t pagesz = getpagesize();
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#ifdef _SC_THREAD_STACK_MIN
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/* avoid stacks smaller than _SC_THREAD_STACK_MIN */
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long min_stack_sz = sysconf(_SC_THREAD_STACK_MIN);
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*sz = MAX(MAX(min_stack_sz, 0), *sz);
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#endif
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/* adjust stack size to a multiple of the page size */
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*sz = ROUND_UP(*sz, pagesz);
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/* allocate one extra page for the guard page */
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*sz += pagesz;
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ptr = mmap(NULL, *sz, PROT_READ | PROT_WRITE,
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MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
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if (ptr == MAP_FAILED) {
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perror("failed to allocate memory for stack");
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abort();
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}
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#if defined(HOST_IA64)
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/* separate register stack */
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guardpage = ptr + (((*sz - pagesz) / 2) & ~pagesz);
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#elif defined(HOST_HPPA)
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/* stack grows up */
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guardpage = ptr + *sz - pagesz;
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#else
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/* stack grows down */
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guardpage = ptr;
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#endif
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if (mprotect(guardpage, pagesz, PROT_NONE) != 0) {
|
|
perror("failed to set up stack guard page");
|
|
abort();
|
|
}
|
|
|
|
#ifdef CONFIG_DEBUG_STACK_USAGE
|
|
for (ptr2 = ptr + pagesz; ptr2 < ptr + *sz; ptr2 += sizeof(uint32_t)) {
|
|
*(uint32_t *)ptr2 = 0xdeadbeaf;
|
|
}
|
|
#endif
|
|
|
|
return ptr;
|
|
}
|
|
|
|
#ifdef CONFIG_DEBUG_STACK_USAGE
|
|
static __thread unsigned int max_stack_usage;
|
|
#endif
|
|
|
|
void qemu_free_stack(void *stack, size_t sz)
|
|
{
|
|
#ifdef CONFIG_DEBUG_STACK_USAGE
|
|
unsigned int usage;
|
|
void *ptr;
|
|
|
|
for (ptr = stack + getpagesize(); ptr < stack + sz;
|
|
ptr += sizeof(uint32_t)) {
|
|
if (*(uint32_t *)ptr != 0xdeadbeaf) {
|
|
break;
|
|
}
|
|
}
|
|
usage = sz - (uintptr_t) (ptr - stack);
|
|
if (usage > max_stack_usage) {
|
|
error_report("thread %d max stack usage increased from %u to %u",
|
|
qemu_get_thread_id(), max_stack_usage, usage);
|
|
max_stack_usage = usage;
|
|
}
|
|
#endif
|
|
|
|
munmap(stack, sz);
|
|
}
|
|
|
|
void sigaction_invoke(struct sigaction *action,
|
|
struct qemu_signalfd_siginfo *info)
|
|
{
|
|
siginfo_t si = {};
|
|
si.si_signo = info->ssi_signo;
|
|
si.si_errno = info->ssi_errno;
|
|
si.si_code = info->ssi_code;
|
|
|
|
/* Convert the minimal set of fields defined by POSIX.
|
|
* Positive si_code values are reserved for kernel-generated
|
|
* signals, where the valid siginfo fields are determined by
|
|
* the signal number. But according to POSIX, it is unspecified
|
|
* whether SI_USER and SI_QUEUE have values less than or equal to
|
|
* zero.
|
|
*/
|
|
if (info->ssi_code == SI_USER || info->ssi_code == SI_QUEUE ||
|
|
info->ssi_code <= 0) {
|
|
/* SIGTERM, etc. */
|
|
si.si_pid = info->ssi_pid;
|
|
si.si_uid = info->ssi_uid;
|
|
} else if (info->ssi_signo == SIGILL || info->ssi_signo == SIGFPE ||
|
|
info->ssi_signo == SIGSEGV || info->ssi_signo == SIGBUS) {
|
|
si.si_addr = (void *)(uintptr_t)info->ssi_addr;
|
|
} else if (info->ssi_signo == SIGCHLD) {
|
|
si.si_pid = info->ssi_pid;
|
|
si.si_status = info->ssi_status;
|
|
si.si_uid = info->ssi_uid;
|
|
}
|
|
action->sa_sigaction(info->ssi_signo, &si, NULL);
|
|
}
|