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util-linux/misc-utils/uuidd.c
Sami Kerola 25d66b4e32 uuidd: use signalfd() and setup_timer() 
Point of this change is to replace use of signal() and alarm() system calls
using newer interfaces.  Nice side effect is that the point where timer was
earlier used cannot be distracted by sending rogue SIGALRM.

Signed-off-by: Sami Kerola <kerolasa@iki.fi>
2015-10-09 11:17:11 +02:00

718 lines
18 KiB
C
Raw Blame History

/*
* uuidd.c --- UUID-generation daemon
*
* Copyright (C) 2007 Theodore Ts'o
*
* %Begin-Header%
* This file may be redistributed under the terms of the GNU Public
* License.
* %End-Header%
*/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <inttypes.h>
#include <errno.h>
#include <err.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <fcntl.h>
#include <signal.h>
#include <string.h>
#include <getopt.h>
#include <sys/signalfd.h>
#include <poll.h>
#include "uuid.h"
#include "uuidd.h"
#include "all-io.h"
#include "c.h"
#include "closestream.h"
#include "strutils.h"
#include "optutils.h"
#include "monotonic.h"
#include "timer.h"
#ifdef HAVE_LIBSYSTEMD
# include <systemd/sd-daemon.h>
#endif
#include "nls.h"
#ifdef __GNUC__
#define CODE_ATTR(x) __attribute__(x)
#else
#define CODE_ATTR(x)
#endif
/* length of textual representation of UUID, including trailing \0 */
#define UUID_STR_LEN 37
/* length of binary representation of UUID */
#define UUID_LEN (sizeof(uuid_t))
/* server loop control structure */
struct uuidd_cxt_t {
const char *cleanup_pidfile;
const char *cleanup_socket;
uint32_t timeout;
unsigned int debug: 1,
quiet: 1,
no_fork: 1,
no_sock: 1;
};
static void __attribute__ ((__noreturn__)) usage(FILE * out)
{
fputs(USAGE_HEADER, out);
fprintf(out, _(" %s [options]\n"), program_invocation_short_name);
fputs(USAGE_SEPARATOR, out);
fputs(_("A daemon for generating UUIDs.\n"), out);
fputs(USAGE_OPTIONS, out);
fputs(_(" -p, --pid <path> path to pid file\n"), out);
fputs(_(" -s, --socket <path> path to socket\n"), out);
fputs(_(" -T, --timeout <sec> specify inactivity timeout\n"), out);
fputs(_(" -k, --kill kill running daemon\n"), out);
fputs(_(" -r, --random test random-based generation\n"), out);
fputs(_(" -t, --time test time-based generation\n"), out);
fputs(_(" -n, --uuids <num> request number of uuids\n"), out);
fputs(_(" -P, --no-pid do not create pid file\n"), out);
fputs(_(" -F, --no-fork do not daemonize using double-fork\n"), out);
fputs(_(" -S, --socket-activation do not create listening socket\n"), out);
fputs(_(" -d, --debug run in debugging mode\n"), out);
fputs(_(" -q, --quiet turn on quiet mode\n"), out);
fputs(USAGE_SEPARATOR, out);
fputs(USAGE_HELP, out);
fputs(USAGE_VERSION, out);
fprintf(out, USAGE_MAN_TAIL("uuidd(8)"));
exit(out == stderr ? EXIT_FAILURE : EXIT_SUCCESS);
}
static void create_daemon(void)
{
uid_t euid;
if (daemon(0, 0))
err(EXIT_FAILURE, "daemon");
euid = geteuid();
if (setreuid(euid, euid) < 0)
err(EXIT_FAILURE, "setreuid");
}
static int call_daemon(const char *socket_path, int op, char *buf,
size_t buflen, int *num, const char **err_context)
{
char op_buf[8];
int op_len;
int s;
ssize_t ret;
int32_t reply_len = 0;
struct sockaddr_un srv_addr;
if (((op == UUIDD_OP_BULK_TIME_UUID) ||
(op == UUIDD_OP_BULK_RANDOM_UUID)) && !num) {
if (err_context)
*err_context = _("bad arguments");
errno = EINVAL;
return -1;
}
if ((s = socket(AF_UNIX, SOCK_STREAM, 0)) < 0) {
if (err_context)
*err_context = _("socket");
return -1;
}
srv_addr.sun_family = AF_UNIX;
strncpy(srv_addr.sun_path, socket_path, sizeof(srv_addr.sun_path));
srv_addr.sun_path[sizeof(srv_addr.sun_path) - 1] = '\0';
if (connect(s, (const struct sockaddr *) &srv_addr,
sizeof(struct sockaddr_un)) < 0) {
if (err_context)
*err_context = _("connect");
close(s);
return -1;
}
if (op == UUIDD_OP_BULK_RANDOM_UUID) {
if ((*num) * UUID_LEN > buflen - 4)
*num = (buflen - 4) / UUID_LEN;
}
op_buf[0] = op;
op_len = 1;
if ((op == UUIDD_OP_BULK_TIME_UUID) ||
(op == UUIDD_OP_BULK_RANDOM_UUID)) {
memcpy(op_buf + 1, num, sizeof(int));
op_len += sizeof(int);
}
ret = write_all(s, op_buf, op_len);
if (ret < 0) {
if (err_context)
*err_context = _("write");
close(s);
return -1;
}
ret = read_all(s, (char *) &reply_len, sizeof(reply_len));
if (ret < 0) {
if (err_context)
*err_context = _("read count");
close(s);
return -1;
}
if (reply_len < 0 || (size_t) reply_len > buflen) {
if (err_context)
*err_context = _("bad response length");
close(s);
return -1;
}
ret = read_all(s, (char *) buf, reply_len);
if ((ret > 0) && (op == UUIDD_OP_BULK_TIME_UUID)) {
if (reply_len >= (int) (UUID_LEN + sizeof(int)))
memcpy(buf + UUID_LEN, num, sizeof(int));
else
*num = -1;
}
if ((ret > 0) && (op == UUIDD_OP_BULK_RANDOM_UUID)) {
if (reply_len >= (int) sizeof(int))
memcpy(buf, num, sizeof(int));
else
*num = -1;
}
close(s);
return ret;
}
/*
* Exclusively create and open a pid file with path @pidfile_path
*
* Return file descriptor of the created pid_file.
*/
static int create_pidfile(struct uuidd_cxt_t *uuidd_cxt,
const char *pidfile_path, int quiet)
{
int fd_pidfile;
struct flock fl;
fd_pidfile = open(pidfile_path, O_CREAT | O_RDWR, 0664);
if (fd_pidfile < 0) {
if (!quiet)
warn(_("cannot open %s"), pidfile_path);
exit(EXIT_FAILURE);
}
uuidd_cxt->cleanup_pidfile = pidfile_path;
fl.l_type = F_WRLCK;
fl.l_whence = SEEK_SET;
fl.l_start = 0;
fl.l_len = 0;
fl.l_pid = 0;
while (fcntl(fd_pidfile, F_SETLKW, &fl) < 0) {
if ((errno == EAGAIN) || (errno == EINTR))
continue;
if (!quiet)
warn(_("cannot lock %s"), pidfile_path);
exit(EXIT_FAILURE);
}
return fd_pidfile;
}
/*
* Create AF_UNIX, SOCK_STREAM socket and bind to @socket_path
*
* If @will_fork is true, then make sure the descriptor
* of the socket is >2, so that it wont be later closed
* during create_daemon().
*
* Return file descriptor corresponding to created socket.
*/
static int create_socket(struct uuidd_cxt_t *uuidd_cxt,
const char *socket_path, int will_fork)
{
struct sockaddr_un my_addr;
mode_t save_umask;
int s;
if ((s = socket(AF_UNIX, SOCK_STREAM, 0)) < 0) {
if (!uuidd_cxt->quiet)
warn(_("couldn't create unix stream socket"));
exit(EXIT_FAILURE);
}
/*
* Make sure the socket isn't using fd numbers 0-2 to avoid it
* getting closed by create_daemon()
*/
while (will_fork && s <= 2) {
s = dup(s);
if (s < 0)
err(EXIT_FAILURE, "dup");
}
/*
* Create the address we will be binding to.
*/
my_addr.sun_family = AF_UNIX;
strncpy(my_addr.sun_path, socket_path, sizeof(my_addr.sun_path));
my_addr.sun_path[sizeof(my_addr.sun_path) - 1] = '\0';
unlink(socket_path);
save_umask = umask(0);
if (bind(s, (const struct sockaddr *) &my_addr,
sizeof(struct sockaddr_un)) < 0) {
if (!uuidd_cxt->quiet)
warn(_("couldn't bind unix socket %s"), socket_path);
exit(EXIT_FAILURE);
}
umask(save_umask);
uuidd_cxt->cleanup_socket = socket_path;
return s;
}
static void __attribute__((__noreturn__)) all_done(const struct uuidd_cxt_t *uuidd_cxt, int ret)
{
if (uuidd_cxt->cleanup_pidfile)
unlink(uuidd_cxt->cleanup_pidfile);
if (uuidd_cxt->cleanup_socket)
unlink(uuidd_cxt->cleanup_socket);
exit(ret);
}
static void handle_signal(const struct uuidd_cxt_t *uuidd_cxt, int fd)
{
struct signalfd_siginfo info;
ssize_t bytes;
bytes = read(fd, &info, sizeof(info));
if (bytes != sizeof(info)) {
if (errno == EAGAIN)
return;
warn(_("receiving signal failed"));
info.ssi_signo = 0;
}
if (info.ssi_signo == SIGPIPE)
return; /* ignored */
all_done(uuidd_cxt, EXIT_SUCCESS);
}
static void timeout_handler(int sig __attribute__((__unused__)),
siginfo_t * info,
void *context __attribute__((__unused__)))
{
if (info->si_code == SI_TIMER)
errx(EXIT_FAILURE, _("timed out"));
}
static void server_loop(const char *socket_path, const char *pidfile_path,
struct uuidd_cxt_t *uuidd_cxt)
{
struct sockaddr_un from_addr;
socklen_t fromlen;
int32_t reply_len = 0;
uuid_t uu;
char reply_buf[1024], *cp;
char op, str[UUID_STR_LEN];
int i, ns, len, num;
int s = 0;
int fd_pidfile = -1;
int ret;
struct pollfd pfd[2];
sigset_t sigmask;
int sigfd;
enum {
POLLFD_SIGNAL = 0,
POLLFD_SOCKET
};
#ifdef HAVE_LIBSYSTEMD
if (!uuidd_cxt->no_sock) /* no_sock implies no_fork and no_pid */
#endif
{
static timer_t t_id;
struct itimerval timeout;
memset(&timeout, 0, sizeof timeout);
timeout.it_value.tv_sec = 30;
if (setup_timer(&t_id, &timeout, &timeout_handler))
err(EXIT_FAILURE, _("cannot not setup timer"));
if (pidfile_path)
fd_pidfile = create_pidfile(uuidd_cxt, pidfile_path, uuidd_cxt->quiet);
ret = call_daemon(socket_path, UUIDD_OP_GETPID, reply_buf,
sizeof(reply_buf), 0, NULL);
cancel_timer(&t_id);
if (ret > 0) {
if (!uuidd_cxt->quiet)
warnx(_("uuidd daemon is already running at pid %s"),
reply_buf);
exit(EXIT_FAILURE);
}
s = create_socket(uuidd_cxt, socket_path,
(!uuidd_cxt->debug || !uuidd_cxt->no_fork));
if (listen(s, SOMAXCONN) < 0) {
if (!uuidd_cxt->quiet)
warn(_("couldn't listen on unix socket %s"), socket_path);
exit(EXIT_FAILURE);
}
if (!uuidd_cxt->debug && !uuidd_cxt->no_fork)
create_daemon();
if (pidfile_path) {
sprintf(reply_buf, "%8d\n", getpid());
if (ftruncate(fd_pidfile, 0))
err(EXIT_FAILURE, _("could not truncate file: %s"), pidfile_path);
write_all(fd_pidfile, reply_buf, strlen(reply_buf));
if (fd_pidfile > 1)
if (close_fd(fd_pidfile) != 0) /* Unlock the pid file */
err(EXIT_FAILURE, _("write failed: %s"), pidfile_path);
}
}
#ifdef HAVE_LIBSYSTEMD
if (uuidd_cxt->no_sock) {
const int ret = sd_listen_fds(0);
if (ret < 0) {
errno = ret * -1;
err(EXIT_FAILURE, _("sd_listen_fds() failed"));
} else if (ret == 0)
errx(EXIT_FAILURE,
_("no file descriptors received, check systemctl status uuidd.socket"));
else if (1 < ret)
errx(EXIT_FAILURE,
_("too many file descriptors received, check uuidd.socket"));
s = SD_LISTEN_FDS_START + 0;
}
#endif
sigemptyset(&sigmask);
sigaddset(&sigmask, SIGHUP);
sigaddset(&sigmask, SIGINT);
sigaddset(&sigmask, SIGTERM);
sigaddset(&sigmask, SIGALRM);
sigaddset(&sigmask, SIGPIPE);
/* Block signals so that they aren't handled according to their
* default dispositions */
sigprocmask(SIG_BLOCK, &sigmask, NULL);
if ((sigfd = signalfd(-1, &sigmask, 0)) < 0)
err(EXIT_FAILURE, _("cannot set signal handler"));
pfd[POLLFD_SIGNAL].fd = sigfd;
pfd[POLLFD_SOCKET].fd = s;
pfd[POLLFD_SIGNAL].events = pfd[POLLFD_SOCKET].events = POLLIN | POLLERR | POLLHUP;
while (1) {
ret = poll(pfd, ARRAY_SIZE(pfd), (uuidd_cxt->timeout == 0 ? -1 : uuidd_cxt->timeout * 1000));
if (ret < 0) {
if (errno == EAGAIN)
continue;
warn(_("poll failed"));
all_done(uuidd_cxt, EXIT_FAILURE);
}
if (ret == 0) /* truen when poll() times out */
all_done(uuidd_cxt, EXIT_SUCCESS);
if (pfd[POLLFD_SIGNAL].revents != 0)
handle_signal(uuidd_cxt, sigfd);
if (pfd[POLLFD_SOCKET].revents == 0)
continue;
fromlen = sizeof(from_addr);
ns = accept(s, (struct sockaddr *) &from_addr, &fromlen);
if (ns < 0) {
if ((errno == EAGAIN) || (errno == EINTR))
continue;
else
err(EXIT_FAILURE, "accept");
}
len = read(ns, &op, 1);
if (len != 1) {
if (len < 0)
warn(_("read failed"));
else
warnx(_("error reading from client, len = %d"),
len);
goto shutdown_socket;
}
if ((op == UUIDD_OP_BULK_TIME_UUID) ||
(op == UUIDD_OP_BULK_RANDOM_UUID)) {
if (read_all(ns, (char *) &num, sizeof(num)) != 4)
goto shutdown_socket;
if (uuidd_cxt->debug)
fprintf(stderr, _("operation %d, incoming num = %d\n"),
op, num);
} else if (uuidd_cxt->debug)
fprintf(stderr, _("operation %d\n"), op);
switch (op) {
case UUIDD_OP_GETPID:
sprintf(reply_buf, "%d", getpid());
reply_len = strlen(reply_buf) + 1;
break;
case UUIDD_OP_GET_MAXOP:
sprintf(reply_buf, "%d", UUIDD_MAX_OP);
reply_len = strlen(reply_buf) + 1;
break;
case UUIDD_OP_TIME_UUID:
num = 1;
__uuid_generate_time(uu, &num);
if (uuidd_cxt->debug) {
uuid_unparse(uu, str);
fprintf(stderr, _("Generated time UUID: %s\n"), str);
}
memcpy(reply_buf, uu, sizeof(uu));
reply_len = sizeof(uu);
break;
case UUIDD_OP_RANDOM_UUID:
num = 1;
__uuid_generate_random(uu, &num);
if (uuidd_cxt->debug) {
uuid_unparse(uu, str);
fprintf(stderr, _("Generated random UUID: %s\n"), str);
}
memcpy(reply_buf, uu, sizeof(uu));
reply_len = sizeof(uu);
break;
case UUIDD_OP_BULK_TIME_UUID:
__uuid_generate_time(uu, &num);
if (uuidd_cxt->debug) {
uuid_unparse(uu, str);
fprintf(stderr, P_("Generated time UUID %s "
"and %d following\n",
"Generated time UUID %s "
"and %d following\n", num - 1),
str, num - 1);
}
memcpy(reply_buf, uu, sizeof(uu));
reply_len = sizeof(uu);
memcpy(reply_buf + reply_len, &num, sizeof(num));
reply_len += sizeof(num);
break;
case UUIDD_OP_BULK_RANDOM_UUID:
if (num < 0)
num = 1;
if (num > 1000)
num = 1000;
if (num * UUID_LEN > (int) (sizeof(reply_buf) - sizeof(num)))
num = (sizeof(reply_buf) - sizeof(num)) / UUID_LEN;
__uuid_generate_random((unsigned char *) reply_buf +
sizeof(num), &num);
if (uuidd_cxt->debug) {
fprintf(stderr, P_("Generated %d UUID:\n",
"Generated %d UUIDs:\n", num), num);
for (i = 0, cp = reply_buf + sizeof(num);
i < num;
i++, cp += UUID_LEN) {
uuid_unparse((unsigned char *)cp, str);
fprintf(stderr, "\t%s\n", str);
}
}
reply_len = (num * UUID_LEN) + sizeof(num);
memcpy(reply_buf, &num, sizeof(num));
break;
default:
if (uuidd_cxt->debug)
fprintf(stderr, _("Invalid operation %d\n"), op);
goto shutdown_socket;
}
write_all(ns, (char *) &reply_len, sizeof(reply_len));
write_all(ns, reply_buf, reply_len);
shutdown_socket:
close(ns);
}
}
static void __attribute__ ((__noreturn__)) unexpected_size(int size)
{
errx(EXIT_FAILURE, _("Unexpected reply length from server %d"), size);
}
int main(int argc, char **argv)
{
const char *socket_path = UUIDD_SOCKET_PATH;
const char *pidfile_path = NULL;
const char *pidfile_path_param = NULL;
const char *err_context = NULL;
char buf[1024], *cp;
char str[UUID_STR_LEN];
uuid_t uu;
int i, c, ret;
int do_type = 0, do_kill = 0, num = 0;
int no_pid = 0;
int s_flag = 0;
struct uuidd_cxt_t uuidd_cxt = { .timeout = 0 };
static const struct option longopts[] = {
{"pid", required_argument, NULL, 'p'},
{"socket", required_argument, NULL, 's'},
{"timeout", required_argument, NULL, 'T'},
{"kill", no_argument, NULL, 'k'},
{"random", no_argument, NULL, 'r'},
{"time", no_argument, NULL, 't'},
{"uuids", required_argument, NULL, 'n'},
{"no-pid", no_argument, NULL, 'P'},
{"no-fork", no_argument, NULL, 'F'},
{"socket-activation", no_argument, NULL, 'S'},
{"debug", no_argument, NULL, 'd'},
{"quiet", no_argument, NULL, 'q'},
{"version", no_argument, NULL, 'V'},
{"help", no_argument, NULL, 'h'},
{NULL, 0, NULL, 0}
};
static const ul_excl_t excl[] = {
{ 'P', 'p' },
{ 'd', 'q' },
{ 'r', 't' },
{ 0 }
};
int excl_st[ARRAY_SIZE(excl)] = UL_EXCL_STATUS_INIT;
setlocale(LC_ALL, "");
bindtextdomain(PACKAGE, LOCALEDIR);
textdomain(PACKAGE);
atexit(close_stdout);
while ((c =
getopt_long(argc, argv, "p:s:T:krtn:PFSdqVh", longopts,
NULL)) != -1) {
err_exclusive_options(c, longopts, excl, excl_st);
switch (c) {
case 'd':
uuidd_cxt.debug = 1;
break;
case 'k':
do_kill++;
break;
case 'n':
num = strtou32_or_err(optarg,
_("failed to parse --uuids"));
break;
case 'p':
pidfile_path_param = optarg;
break;
case 'P':
no_pid = 1;
break;
case 'F':
uuidd_cxt.no_fork = 1;
break;
case 'S':
#ifdef HAVE_LIBSYSTEMD
uuidd_cxt.no_sock = 1;
uuidd_cxt.no_fork = 1;
no_pid = 1;
#else
errx(EXIT_FAILURE, _("uuidd has been built without "
"support for socket activation"));
#endif
break;
case 'q':
uuidd_cxt.quiet = 1;
break;
case 'r':
do_type = UUIDD_OP_RANDOM_UUID;
break;
case 's':
socket_path = optarg;
s_flag = 1;
break;
case 't':
do_type = UUIDD_OP_TIME_UUID;
break;
case 'T':
uuidd_cxt.timeout = strtou32_or_err(optarg,
_("failed to parse --timeout"));
break;
case 'V':
printf(UTIL_LINUX_VERSION);
return EXIT_SUCCESS;
case 'h':
usage(stdout);
default:
usage(stderr);
}
}
if (!no_pid && !pidfile_path_param)
pidfile_path = UUIDD_PIDFILE_PATH;
else if (pidfile_path_param)
pidfile_path = pidfile_path_param;
/* custom socket path and socket-activation make no sense */
if (s_flag && uuidd_cxt.no_sock && !uuidd_cxt.quiet)
warnx(_("Both --socket-activation and --socket specified. "
"Ignoring --socket."));
if (num && do_type) {
ret = call_daemon(socket_path, do_type + 2, buf,
sizeof(buf), &num, &err_context);
if (ret < 0)
err(EXIT_FAILURE, _("error calling uuidd daemon (%s)"),
err_context ? : _("unexpected error"));
if (do_type == UUIDD_OP_TIME_UUID) {
if (ret != sizeof(uu) + sizeof(num))
unexpected_size(ret);
uuid_unparse((unsigned char *) buf, str);
printf(P_("%s and %d subsequent UUID\n",
"%s and %d subsequent UUIDs\n", num - 1),
str, num - 1);
} else {
printf(_("List of UUIDs:\n"));
cp = buf + 4;
if (ret != (int) (sizeof(num) + num * sizeof(uu)))
unexpected_size(ret);
for (i = 0; i < num; i++, cp += UUID_LEN) {
uuid_unparse((unsigned char *) cp, str);
printf("\t%s\n", str);
}
}
return EXIT_SUCCESS;
}
if (do_type) {
ret = call_daemon(socket_path, do_type, (char *) &uu,
sizeof(uu), 0, &err_context);
if (ret < 0)
err(EXIT_FAILURE, _("error calling uuidd daemon (%s)"),
err_context ? : _("unexpected error"));
if (ret != sizeof(uu))
unexpected_size(ret);
uuid_unparse(uu, str);
printf("%s\n", str);
return EXIT_SUCCESS;
}
if (do_kill) {
ret = call_daemon(socket_path, UUIDD_OP_GETPID, buf, sizeof(buf), 0, NULL);
if ((ret > 0) && ((do_kill = atoi((char *) buf)) > 0)) {
ret = kill(do_kill, SIGTERM);
if (ret < 0) {
if (!uuidd_cxt.quiet)
warn(_("couldn't kill uuidd running "
"at pid %d"), do_kill);
return EXIT_FAILURE;
}
if (!uuidd_cxt.quiet)
printf(_("Killed uuidd running at pid %d.\n"),
do_kill);
}
return EXIT_SUCCESS;
}
server_loop(socket_path, pidfile_path, &uuidd_cxt);
return EXIT_SUCCESS;
}
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