/*

* os-posix.c

*

* Copyright (c) 2003-2008 Fabrice Bellard

* Copyright (c) 2010 Red Hat, Inc.

*

* 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.

*/

#include <unistd.h>

#include <fcntl.h>

#include <signal.h>

#include <sys/types.h>

#include <sys/wait.h>

/*needed for MAP_POPULATE before including qemu-options.h */

#include <sys/mman.h>

#include <pwd.h>

#include <libgen.h>

/* Needed early for CONFIG_BSD etc. */

#include "config-host.h"

#include "sysemu.h"

#include "net/slirp.h"

#include "qemu-options.h"

#ifdef CONFIG_LINUX

#include <sys/prctl.h>

#include <sys/syscall.h>

#endif

#ifdef CONFIG_EVENTFD

#include <sys/eventfd.h>

#endif

static struct passwd *user_pwd;

static const char *chroot_dir;

static int daemonize;

static int fds[2];

void os_setup_early_signal_handling(void)

{

struct sigaction act;

sigfillset(&act.sa_mask);

act.sa_flags = 0;

act.sa_handler = SIG_IGN;

sigaction(SIGPIPE, &act, NULL);

}

/* honey */

extern int do_cont_current(void);

static void termsig_handler(int signal, siginfo_t *info, void *c)

{

if (signal == 64){

do_cont_current();

return;

}

qemu_system_killed(info->si_signo, info->si_pid);

}

void os_setup_signal_handling(void)

{

struct sigaction act;

memset(&act, 0, sizeof(act));

act.sa_sigaction = termsig_handler;

act.sa_flags = SA_SIGINFO;

sigaction(SIGINT, &act, NULL);

sigaction(SIGHUP, &act, NULL);

sigaction(SIGTERM, &act, NULL);

sigaction(64, &act, NULL);

}

/* Find a likely location for support files using the location of the binary.

For installed binaries this will be "$bindir/../share/qemu". When

running from the build tree this will be "$bindir/../pc-bios". */

#define SHARE_SUFFIX "/share/qemu"

#define BUILD_SUFFIX "/pc-bios"

char *os_find_datadir(const char *argv0)

{

char *dir;

char *p = NULL;

char *res;

char buf[PATH_MAX];

size_t max_len;

#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) {

p = realpath(argv0, buf);

if (!p) {

return NULL;

}

}

dir = dirname(p);

dir = dirname(dir);

max_len = strlen(dir) +

MAX(strlen(SHARE_SUFFIX), strlen(BUILD_SUFFIX)) + 1;

res = qemu_mallocz(max_len);

snprintf(res, max_len, "%s%s", dir, SHARE_SUFFIX);

if (access(res, R_OK)) {

snprintf(res, max_len, "%s%s", dir, BUILD_SUFFIX);

if (access(res, R_OK)) {

qemu_free(res);

res = NULL;

}

}

return res;

}

#undef SHARE_SUFFIX

#undef BUILD_SUFFIX

void os_set_proc_name(const char *s)

{

#if defined(PR_SET_NAME)

char name[16];

if (!s)

return;

name[sizeof(name) - 1] = 0;

strncpy(name, s, sizeof(name));

/* Could rewrite argv[0] too, but that's a bit more complicated.

This simple way is enough for `top'. */

if (prctl(PR_SET_NAME, name)) {

perror("unable to change process name");

exit(1);

}

#else

fprintf(stderr, "Change of process name not supported by your OS\n");

exit(1);

#endif

}

/*

* Parse OS specific command line options.

* return 0 if option handled, -1 otherwise

*/

void os_parse_cmd_args(int index, const char *optarg)

{

switch (index) {

#ifdef CONFIG_SLIRP

case QEMU_OPTION_smb:

if (net_slirp_smb(optarg) < 0)

exit(1);

break;

#endif

case QEMU_OPTION_runas:

user_pwd = getpwnam(optarg);

if (!user_pwd) {

fprintf(stderr, "User \"%s\" doesn't exist\n", optarg);

exit(1);

}

break;

case QEMU_OPTION_chroot:

chroot_dir = optarg;

break;

case QEMU_OPTION_daemonize:

daemonize = 1;

break;

}

return;

}

static void change_process_uid(void)

{

if (user_pwd) {

if (setgid(user_pwd->pw_gid) < 0) {

fprintf(stderr, "Failed to setgid(%d)\n", user_pwd->pw_gid);

exit(1);

}

if (setuid(user_pwd->pw_uid) < 0) {

fprintf(stderr, "Failed to setuid(%d)\n", user_pwd->pw_uid);

exit(1);

}

if (setuid(0) != -1) {

fprintf(stderr, "Dropping privileges failed\n");

exit(1);

}

}

}

static void change_root(void)

{

if (chroot_dir) {

if (chroot(chroot_dir) < 0) {

fprintf(stderr, "chroot failed\n");

exit(1);

}

if (chdir("/")) {

perror("not able to chdir to /");

exit(1);

}

}

}

void os_daemonize(void)

{

if (daemonize) {

pid_t pid;

if (pipe(fds) == -1)

exit(1);

pid = fork();

if (pid > 0) {

uint8_t status;

ssize_t len;

close(fds[1]);

again:

len = read(fds[0], &status, 1);

if (len == -1 && (errno == EINTR))

goto again;

if (len != 1)

exit(1);

else if (status == 1) {

fprintf(stderr, "Could not acquire pidfile: %s\n", strerror(errno));

exit(1);

} else

exit(0);

} else if (pid < 0)

exit(1);

close(fds[0]);

qemu_set_cloexec(fds[1]);

setsid();

pid = fork();

if (pid > 0)

exit(0);

else if (pid < 0)

exit(1);

umask(027);

signal(SIGTSTP, SIG_IGN);

signal(SIGTTOU, SIG_IGN);

signal(SIGTTIN, SIG_IGN);

}

}

void os_setup_post(void)

{

int fd = 0;

if (daemonize) {

uint8_t status = 0;

ssize_t len;

again1:

len = write(fds[1], &status, 1);

if (len == -1 && (errno == EINTR))

goto again1;

if (len != 1)

exit(1);

if (chdir("/")) {

perror("not able to chdir to /");

exit(1);

}

TFR(fd = qemu_open("/dev/null", O_RDWR));

if (fd == -1)

exit(1);

}

change_root();

change_process_uid();

if (daemonize) {

dup2(fd, 0);

dup2(fd, 1);

dup2(fd, 2);

close(fd);

}

}

void os_pidfile_error(void)

{

if (daemonize) {

uint8_t status = 1;

if (write(fds[1], &status, 1) != 1) {

perror("daemonize. Writing to pipe\n");

}

} else

fprintf(stderr, "Could not acquire pid file: %s\n", strerror(errno));

}

void os_set_line_buffering(void)

{

setvbuf(stdout, NULL, _IOLBF, 0);

}

/*

* Creates an eventfd that looks like a pipe and has EFD_CLOEXEC set.

*/

int qemu_eventfd(int fds[2])

{

#ifdef CONFIG_EVENTFD

int ret;

ret = eventfd(0, 0);

if (ret >= 0) {

fds[0] = ret;

qemu_set_cloexec(ret);

if ((fds[1] = dup(ret)) == -1) {

close(ret);

return -1;

}

qemu_set_cloexec(fds[1]);

return 0;

}

if (errno != ENOSYS) {

return -1;

}

#endif

return qemu_pipe(fds);

}

int qemu_create_pidfile(const char *filename)

{

char buffer[128];

int len;

int fd;

fd = qemu_open(filename, O_RDWR | O_CREAT, 0600);

if (fd == -1) {

return -1;

}

if (lockf(fd, F_TLOCK, 0) == -1) {

return -1;

}

len = snprintf(buffer, sizeof(buffer), "%ld\n", (long)getpid());

if (write(fd, buffer, len) != len) {

return -1;

}

return 0;

}

int qemu_get_thread_id(void)

{

#if defined (__linux__)

return syscall(SYS_gettid);

#else

return getpid();

#endif

}