#include <sys/socket.h>

#include <sys/types.h>

#include <assert.h>

#include <time.h>

#include <string.h>

#include <stdio.h>

#include <errno.h>

#include <unistd.h>

#include <sys/poll.h>

#include <sys/epoll.h>

#include <sys/un.h>

#include <fcntl.h>

#include <sys/signalfd.h>

#include "util.h"

#include "log.h"

#include "sd-daemon.h"

#include "fdset.h"

#define SERVER_FD_MAX 16

typedef struct Stream Stream;

typedef struct Server {

FDSet *syslog_fds;

int kmsg_fd;

int epoll_fd;

int signal_fd;

} Server;

static void server_done(Server *s) {

assert(s);

if (s->epoll_fd >= 0)

close_nointr_nofail(s->epoll_fd);

if (s->kmsg_fd >= 0)

close_nointr_nofail(s->kmsg_fd);

if (s->signal_fd >= 0)

close_nointr_nofail(s->signal_fd);

if (s->syslog_fds)

fdset_free(s->syslog_fds);

}

static int server_init(Server *s, unsigned n_sockets) {

int r;

unsigned i;

struct epoll_event ev;

sigset_t mask;

assert(s);

assert(n_sockets > 0);

zero(*s);

s->kmsg_fd = s->signal_fd = -1;

if ((s->epoll_fd = epoll_create1(EPOLL_CLOEXEC)) < 0) {

r = -errno;

log_error("Failed to create epoll object: %s", strerror(errno));

goto fail;

}

if (!(s->syslog_fds = fdset_new())) {

r = -ENOMEM;

log_error("Failed to allocate file descriptor set: %s", strerror(errno));

goto fail;

}

for (i = 0; i < n_sockets; i++) {

int fd;

fd = SD_LISTEN_FDS_START+i;

if ((r = sd_is_socket(fd, AF_UNSPEC, SOCK_DGRAM, -1)) < 0) {

log_error("Failed to determine file descriptor type: %s", strerror(-r));

goto fail;

}

if (!r) {

log_error("Wrong file descriptor type.");

r = -EINVAL;

goto fail;

}

zero(ev);

ev.events = EPOLLIN;

ev.data.fd = fd;

if (epoll_ctl(s->epoll_fd, EPOLL_CTL_ADD, fd, &ev) < 0) {

r = -errno;

log_error("Failed to add server fd to epoll object: %s", strerror(errno));

goto fail;

}

if ((r = fdset_put(s->syslog_fds, fd)) < 0) {

log_error("Failed to store file descriptor in set: %s", strerror(-r));

goto fail;

}

}

if ((s->kmsg_fd = open("/dev/kmsg", O_WRONLY|O_NOCTTY|O_CLOEXEC)) < 0) {

log_error("Failed to open /dev/kmsg for logging: %m");

return -errno;

}

assert_se(sigemptyset(&mask) == 0);

sigset_add_many(&mask, SIGINT, SIGTERM, -1);

assert_se(sigprocmask(SIG_SETMASK, &mask, NULL) == 0);

if ((s->signal_fd = signalfd(-1, &mask, SFD_NONBLOCK|SFD_CLOEXEC)) < 0) {

log_error("signalfd(): %m");

return -errno;

}

zero(ev);

ev.events = EPOLLIN;

ev.data.fd = s->signal_fd;

if (epoll_ctl(s->epoll_fd, EPOLL_CTL_ADD, s->signal_fd, &ev) < 0) {

log_error("epoll_ctl(): %m");

return -errno;

}

return 0;

fail:

server_done(s);

return r;

}

static void skip_date(const char **buf) {

enum {

LETTER,

SPACE,

NUMBER,

SPACE_OR_NUMBER,

COLON

} sequence[] = {

LETTER, LETTER, LETTER,

SPACE,

SPACE_OR_NUMBER, NUMBER,

SPACE,

SPACE_OR_NUMBER, NUMBER,

COLON,

SPACE_OR_NUMBER, NUMBER,

COLON,

SPACE_OR_NUMBER, NUMBER,

SPACE

};

const char *p;

unsigned i;

assert(buf);

assert(*buf);

p = *buf;

for (i = 0; i < ELEMENTSOF(sequence); i++, p++) {

if (!*p)

return;

switch (sequence[i]) {

case SPACE:

if (*p != ' ')

return;

break;

case SPACE_OR_NUMBER:

if (*p == ' ')

break;

/* fall through */

case NUMBER:

if (*p < '0' || *p > '9')

return;

break;

case LETTER:

if (!(*p >= 'A' && *p <= 'Z') &&

!(*p >= 'a' && *p <= 'z'))

return;

break;

case COLON:

if (*p != ':')

return;

break;

}

}

*buf = p;

}

static int read_process(const char **buf, struct iovec *iovec) {

const char *p;

size_t l;

assert(buf);

assert(*buf);

assert(iovec);

p = *buf;

p += strspn(p, WHITESPACE);

l = strcspn(p, WHITESPACE);

if (l <= 0 ||

p[l-1] != ':')

return 0;

l--;

if (p[l-1] == ']') {

size_t k = l-1;

for (;;) {

if (p[k] == '[') {

l = k;

break;

}

if (k == 0)

break;

k--;

}

}

iovec->iov_base = (char*) p;

iovec->iov_len = l;

*buf = p + l;

return 1;

}

static void skip_pid(const char **buf) {

const char *p;

assert(buf);

assert(*buf);

p = *buf;

if (*p != '[')

return;

p++;

p += strspn(p, "0123456789");

if (*p != ']')

return;

p++;

*buf = p;

}

static int write_message(Server *s, const char *buf, struct ucred *ucred) {

ssize_t k;

char priority[6], pid[16];

struct iovec iovec[5];

unsigned i = 0;

char *process = NULL;

int r = 0;

int prio = LOG_USER | LOG_INFO;

assert(s);

assert(buf);

parse_syslog_priority((char**) &buf, &prio);

if (*buf == 0)

return 0;

if ((prio & LOG_FACMASK) == 0)

prio = LOG_USER | LOG_PRI(prio);

/* First, set priority field */

snprintf(priority, sizeof(priority), "<%i>", prio);

char_array_0(priority);

IOVEC_SET_STRING(iovec[i++], priority);

/* Second, skip date */

skip_date(&buf);

/* Then, add process if set */

if (read_process(&buf, &iovec[i]) > 0)

i++;

else if (ucred &&

ucred->pid > 0 &&

get_process_name(ucred->pid, &process) >= 0)

IOVEC_SET_STRING(iovec[i++], process);

/* Skip the stored PID if we have a better one */

if (ucred) {

snprintf(pid, sizeof(pid), "[%lu]: ", (unsigned long) ucred->pid);

char_array_0(pid);

IOVEC_SET_STRING(iovec[i++], pid);

skip_pid(&buf);

if (*buf == ':')

buf++;

buf += strspn(buf, WHITESPACE);

}

/* Is the remaining message empty? */

if (*buf) {

/* And the rest is the message */

IOVEC_SET_STRING(iovec[i++], buf);

IOVEC_SET_STRING(iovec[i++], "\n");

if ((k = writev(s->kmsg_fd, iovec, i)) <= 0) {

log_error("Failed to write log message to kmsg: %s", k < 0 ? strerror(errno) : "short write");

r = k < 0 ? -errno : -EIO;

}

}

free(process);

return r;

}

static int process_event(Server *s, struct epoll_event *ev) {

assert(s);

if (ev->events != EPOLLIN) {

log_info("Got invalid event from epoll.");

return -EIO;

}

if (ev->data.fd == s->signal_fd) {

struct signalfd_siginfo sfsi;

ssize_t n;

if ((n = read(s->signal_fd, &sfsi, sizeof(sfsi))) != sizeof(sfsi)) {

if (n >= 0)

return -EIO;

if (errno == EINTR || errno == EAGAIN)

return 0;

return -errno;

}

log_debug("Received SIG%s", signal_to_string(sfsi.ssi_signo));

return 0;

} else {

for (;;) {

char buf[LINE_MAX+1];

struct msghdr msghdr;

struct iovec iovec;

struct ucred *ucred;

union {

struct cmsghdr cmsghdr;

uint8_t buf[CMSG_SPACE(sizeof(struct ucred))];

} control;

ssize_t n;

int k;

char *e;

zero(iovec);

iovec.iov_base = buf;

iovec.iov_len = sizeof(buf)-1;

zero(control);

zero(msghdr);

msghdr.msg_iov = &iovec;

msghdr.msg_iovlen = 1;

msghdr.msg_control = &control;

msghdr.msg_controllen = sizeof(control);

if ((n = recvmsg(ev->data.fd, &msghdr, MSG_DONTWAIT)) < 0) {

if (errno == EINTR || errno == EAGAIN)

return 1;

log_error("recvmsg() failed: %m");

return -errno;

}

if (msghdr.msg_controllen >= CMSG_LEN(sizeof(struct ucred)) &&

control.cmsghdr.cmsg_level == SOL_SOCKET &&

control.cmsghdr.cmsg_type == SCM_CREDENTIALS &&

control.cmsghdr.cmsg_len == CMSG_LEN(sizeof(struct ucred)))

ucred = (struct ucred*) CMSG_DATA(&control.cmsghdr);

else

ucred = NULL;

if ((e = memchr(buf, '\n', n)))

*e = 0;

else

buf[n] = 0;

if ((k = write_message(s, strstrip(buf), ucred)) < 0)

return k;

}

}

return 1;

}

int main(int argc, char *argv[]) {

Server server;

int r = EXIT_FAILURE, n;

if (getppid() != 1) {

log_error("This program should be invoked by init only.");

return EXIT_FAILURE;

}

if (argc > 1) {

log_error("This program does not take arguments.");

return EXIT_FAILURE;

}

log_set_target(LOG_TARGET_KMSG);

log_parse_environment();

log_open();

umask(0022);

if ((n = sd_listen_fds(true)) < 0) {

log_error("Failed to read listening file descriptors from environment: %s", strerror(-r));

return EXIT_FAILURE;

}

if (n <= 0 || n > SERVER_FD_MAX) {

log_error("No or too many file descriptors passed.");

return EXIT_FAILURE;

}

if (server_init(&server, (unsigned) n) < 0)

return EXIT_FAILURE;

log_debug("systemd-kmsg-syslogd running as pid %lu", (unsigned long) getpid());

sd_notify(false,

"READY=1\n"

"STATUS=Processing messages...");

for (;;) {

struct epoll_event event;

int k;

if ((k = epoll_wait(server.epoll_fd, &event, 1, -1)) < 0) {

if (errno == EINTR)

continue;

log_error("epoll_wait() failed: %m");

goto fail;

}

if (k <= 0)

break;

if ((k = process_event(&server, &event)) < 0)

goto fail;

if (k == 0)

break;

}

r = EXIT_SUCCESS;

log_debug("systemd-kmsg-syslogd stopped as pid %lu", (unsigned long) getpid());

fail:

sd_notify(false,

"STATUS=Shutting down...");

server_done(&server);

return r;

}