qemu/util/oslib-posix.c

418 lines
9.8 KiB
C

/*
* os-posix-lib.c
*
* Copyright (c) 2003-2008 Fabrice Bellard
* Copyright (c) 2010 Red Hat, Inc.
*
* QEMU library functions on POSIX which are shared between QEMU and
* the QEMU tools.
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
/* The following block of code temporarily renames the daemon() function so the
compiler does not see the warning associated with it in stdlib.h on OSX */
#ifdef __APPLE__
#define daemon qemu_fake_daemon_function
#include <stdlib.h>
#undef daemon
extern int daemon(int, int);
#endif
#if defined(__linux__) && (defined(__x86_64__) || defined(__arm__))
/* Use 2 MiB alignment so transparent hugepages can be used by KVM.
Valgrind does not support alignments larger than 1 MiB,
therefore we need special code which handles running on Valgrind. */
# define QEMU_VMALLOC_ALIGN (512 * 4096)
#elif defined(__linux__) && defined(__s390x__)
/* Use 1 MiB (segment size) alignment so gmap can be used by KVM. */
# define QEMU_VMALLOC_ALIGN (256 * 4096)
#else
# define QEMU_VMALLOC_ALIGN getpagesize()
#endif
#define HUGETLBFS_MAGIC 0x958458f6
#include <termios.h>
#include <unistd.h>
#include <glib/gprintf.h>
#include "config-host.h"
#include "sysemu/sysemu.h"
#include "trace.h"
#include "qemu/sockets.h"
#include <sys/mman.h>
#include <libgen.h>
#include <setjmp.h>
#include <sys/signal.h>
#ifdef CONFIG_LINUX
#include <sys/syscall.h>
#include <sys/vfs.h>
#endif
#ifdef __FreeBSD__
#include <sys/sysctl.h>
#endif
int qemu_get_thread_id(void)
{
#if defined(__linux__)
return syscall(SYS_gettid);
#else
return getpid();
#endif
}
int qemu_daemon(int nochdir, int noclose)
{
return daemon(nochdir, noclose);
}
void *qemu_oom_check(void *ptr)
{
if (ptr == NULL) {
fprintf(stderr, "Failed to allocate memory: %s\n", strerror(errno));
abort();
}
return ptr;
}
void *qemu_try_memalign(size_t alignment, size_t size)
{
void *ptr;
if (alignment < sizeof(void*)) {
alignment = sizeof(void*);
}
#if defined(_POSIX_C_SOURCE) && !defined(__sun__)
int ret;
ret = posix_memalign(&ptr, alignment, size);
if (ret != 0) {
errno = ret;
ptr = NULL;
}
#elif defined(CONFIG_BSD)
ptr = valloc(size);
#else
ptr = memalign(alignment, size);
#endif
trace_qemu_memalign(alignment, size, ptr);
return ptr;
}
void *qemu_memalign(size_t alignment, size_t size)
{
return qemu_oom_check(qemu_try_memalign(alignment, size));
}
/* alloc shared memory pages */
void *qemu_anon_ram_alloc(size_t size, uint64_t *alignment)
{
size_t align = QEMU_VMALLOC_ALIGN;
size_t total = size + align - getpagesize();
void *ptr = mmap(0, total, PROT_READ | PROT_WRITE,
MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
size_t offset = QEMU_ALIGN_UP((uintptr_t)ptr, align) - (uintptr_t)ptr;
if (ptr == MAP_FAILED) {
return NULL;
}
if (alignment) {
*alignment = align;
}
ptr += offset;
total -= offset;
if (offset > 0) {
munmap(ptr - offset, offset);
}
if (total > size) {
munmap(ptr + size, total - size);
}
trace_qemu_anon_ram_alloc(size, ptr);
return ptr;
}
void qemu_vfree(void *ptr)
{
trace_qemu_vfree(ptr);
free(ptr);
}
void qemu_anon_ram_free(void *ptr, size_t size)
{
trace_qemu_anon_ram_free(ptr, size);
if (ptr) {
munmap(ptr, size);
}
}
void qemu_set_block(int fd)
{
int f;
f = fcntl(fd, F_GETFL);
fcntl(fd, F_SETFL, f & ~O_NONBLOCK);
}
void qemu_set_nonblock(int fd)
{
int f;
f = fcntl(fd, F_GETFL);
fcntl(fd, F_SETFL, f | O_NONBLOCK);
}
int socket_set_fast_reuse(int fd)
{
int val = 1, ret;
ret = setsockopt(fd, SOL_SOCKET, SO_REUSEADDR,
(const char *)&val, sizeof(val));
assert(ret == 0);
return ret;
}
void qemu_set_cloexec(int fd)
{
int f;
f = fcntl(fd, F_GETFD);
fcntl(fd, F_SETFD, f | FD_CLOEXEC);
}
/*
* Creates a pipe with FD_CLOEXEC set on both file descriptors
*/
int qemu_pipe(int pipefd[2])
{
int ret;
#ifdef CONFIG_PIPE2
ret = pipe2(pipefd, O_CLOEXEC);
if (ret != -1 || errno != ENOSYS) {
return ret;
}
#endif
ret = pipe(pipefd);
if (ret == 0) {
qemu_set_cloexec(pipefd[0]);
qemu_set_cloexec(pipefd[1]);
}
return ret;
}
int qemu_utimens(const char *path, const struct timespec *times)
{
struct timeval tv[2], tv_now;
struct stat st;
int i;
#ifdef CONFIG_UTIMENSAT
int ret;
ret = utimensat(AT_FDCWD, path, times, AT_SYMLINK_NOFOLLOW);
if (ret != -1 || errno != ENOSYS) {
return ret;
}
#endif
/* Fallback: use utimes() instead of utimensat() */
/* happy if special cases */
if (times[0].tv_nsec == UTIME_OMIT && times[1].tv_nsec == UTIME_OMIT) {
return 0;
}
if (times[0].tv_nsec == UTIME_NOW && times[1].tv_nsec == UTIME_NOW) {
return utimes(path, NULL);
}
/* prepare for hard cases */
if (times[0].tv_nsec == UTIME_NOW || times[1].tv_nsec == UTIME_NOW) {
gettimeofday(&tv_now, NULL);
}
if (times[0].tv_nsec == UTIME_OMIT || times[1].tv_nsec == UTIME_OMIT) {
stat(path, &st);
}
for (i = 0; i < 2; i++) {
if (times[i].tv_nsec == UTIME_NOW) {
tv[i].tv_sec = tv_now.tv_sec;
tv[i].tv_usec = tv_now.tv_usec;
} else if (times[i].tv_nsec == UTIME_OMIT) {
tv[i].tv_sec = (i == 0) ? st.st_atime : st.st_mtime;
tv[i].tv_usec = 0;
} else {
tv[i].tv_sec = times[i].tv_sec;
tv[i].tv_usec = times[i].tv_nsec / 1000;
}
}
return utimes(path, &tv[0]);
}
char *
qemu_get_local_state_pathname(const char *relative_pathname)
{
return g_strdup_printf("%s/%s", CONFIG_QEMU_LOCALSTATEDIR,
relative_pathname);
}
void qemu_set_tty_echo(int fd, bool echo)
{
struct termios tty;
tcgetattr(fd, &tty);
if (echo) {
tty.c_lflag |= ECHO | ECHONL | ICANON | IEXTEN;
} else {
tty.c_lflag &= ~(ECHO | ECHONL | ICANON | IEXTEN);
}
tcsetattr(fd, TCSANOW, &tty);
}
static char exec_dir[PATH_MAX];
void qemu_init_exec_dir(const char *argv0)
{
char *dir;
char *p = NULL;
char buf[PATH_MAX];
assert(!exec_dir[0]);
#if defined(__linux__)
{
int len;
len = readlink("/proc/self/exe", buf, sizeof(buf) - 1);
if (len > 0) {
buf[len] = 0;
p = buf;
}
}
#elif defined(__FreeBSD__)
{
static int mib[4] = {CTL_KERN, KERN_PROC, KERN_PROC_PATHNAME, -1};
size_t len = sizeof(buf) - 1;
*buf = '\0';
if (!sysctl(mib, ARRAY_SIZE(mib), buf, &len, NULL, 0) &&
*buf) {
buf[sizeof(buf) - 1] = '\0';
p = buf;
}
}
#endif
/* If we don't have any way of figuring out the actual executable
location then try argv[0]. */
if (!p) {
if (!argv0) {
return;
}
p = realpath(argv0, buf);
if (!p) {
return;
}
}
dir = dirname(p);
pstrcpy(exec_dir, sizeof(exec_dir), dir);
}
char *qemu_get_exec_dir(void)
{
return g_strdup(exec_dir);
}
static sigjmp_buf sigjump;
static void sigbus_handler(int signal)
{
siglongjmp(sigjump, 1);
}
static size_t fd_getpagesize(int fd)
{
#ifdef CONFIG_LINUX
struct statfs fs;
int ret;
if (fd != -1) {
do {
ret = fstatfs(fd, &fs);
} while (ret != 0 && errno == EINTR);
if (ret == 0 && fs.f_type == HUGETLBFS_MAGIC) {
return fs.f_bsize;
}
}
#endif
return getpagesize();
}
void os_mem_prealloc(int fd, char *area, size_t memory)
{
int ret;
struct sigaction act, oldact;
sigset_t set, oldset;
memset(&act, 0, sizeof(act));
act.sa_handler = &sigbus_handler;
act.sa_flags = 0;
ret = sigaction(SIGBUS, &act, &oldact);
if (ret) {
perror("os_mem_prealloc: failed to install signal handler");
exit(1);
}
/* unblock SIGBUS */
sigemptyset(&set);
sigaddset(&set, SIGBUS);
pthread_sigmask(SIG_UNBLOCK, &set, &oldset);
if (sigsetjmp(sigjump, 1)) {
fprintf(stderr, "os_mem_prealloc: Insufficient free host memory "
"pages available to allocate guest RAM\n");
exit(1);
} else {
int i;
size_t hpagesize = fd_getpagesize(fd);
/* MAP_POPULATE silently ignores failures */
memory = (memory + hpagesize - 1) & -hpagesize;
for (i = 0; i < (memory / hpagesize); i++) {
memset(area + (hpagesize * i), 0, 1);
}
ret = sigaction(SIGBUS, &oldact, NULL);
if (ret) {
perror("os_mem_prealloc: failed to reinstall signal handler");
exit(1);
}
pthread_sigmask(SIG_SETMASK, &oldset, NULL);
}
}