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e9174f29c7
systemd/src/journal/journal-send.c
Zbigniew Jędrzejewski-Szmek 6c045c0b4c journal: fail silently in sd_j_sendv() if journal is unavailable 
"syslog(3) and sd_journal_print() may largely be used interchangeably
functionality-wise" according to sd_journal_print(3). This socket
should be always available except in rare circumstatances, and we
don't random applications to fail on logging, so let's do what syslog
did. The alternative of forcing all callers to do error handling for
this rare case doesn't really have any benefits, since if they can't
log there isn't much they can do anyway.

https://bugzilla.redhat.com/show_bug.cgi?id=1023041
2013-12-03 12:11:18 -05:00

579 lines
17 KiB
C
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/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
/***
This file is part of systemd.
Copyright 2011 Lennart Poettering
systemd is free software; you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
systemd is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/
#include <sys/socket.h>
#include <sys/un.h>
#include <errno.h>
#include <stddef.h>
#include <unistd.h>
#include <fcntl.h>
#include <printf.h>
#define SD_JOURNAL_SUPPRESS_LOCATION
#include "sd-journal.h"
#include "util.h"
#include "socket-util.h"
#define SNDBUF_SIZE (8*1024*1024)
#define ALLOCA_CODE_FUNC(f, func) \
do { \
size_t _fl; \
const char *_func = (func); \
char **_f = &(f); \
_fl = strlen(_func) + 1; \
*_f = alloca(_fl + 10); \
memcpy(*_f, "CODE_FUNC=", 10); \
memcpy(*_f + 10, _func, _fl); \
} while(false)
/* We open a single fd, and we'll share it with the current process,
* all its threads, and all its subprocesses. This means we need to
* initialize it atomically, and need to operate on it atomically
* never assuming we are the only user */
static int journal_fd(void) {
int fd;
static int fd_plus_one = 0;
retry:
if (fd_plus_one > 0)
return fd_plus_one - 1;
fd = socket(AF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC, 0);
if (fd < 0)
return -errno;
fd_inc_sndbuf(fd, SNDBUF_SIZE);
if (!__sync_bool_compare_and_swap(&fd_plus_one, 0, fd+1)) {
close_nointr_nofail(fd);
goto retry;
}
return fd;
}
_public_ int sd_journal_print(int priority, const char *format, ...) {
int r;
va_list ap;
va_start(ap, format);
r = sd_journal_printv(priority, format, ap);
va_end(ap);
return r;
}
_public_ int sd_journal_printv(int priority, const char *format, va_list ap) {
/* FIXME: Instead of limiting things to LINE_MAX we could do a
C99 variable-length array on the stack here in a loop. */
char buffer[8 + LINE_MAX], p[11]; struct iovec iov[2];
assert_return(priority >= 0, -EINVAL);
assert_return(priority <= 7, -EINVAL);
assert_return(format, -EINVAL);
snprintf(p, sizeof(p), "PRIORITY=%i", priority & LOG_PRIMASK);
char_array_0(p);
memcpy(buffer, "MESSAGE=", 8);
vsnprintf(buffer+8, sizeof(buffer) - 8, format, ap);
char_array_0(buffer);
zero(iov);
IOVEC_SET_STRING(iov[0], buffer);
IOVEC_SET_STRING(iov[1], p);
return sd_journal_sendv(iov, 2);
}
_printf_(1, 0) static int fill_iovec_sprintf(const char *format, va_list ap, int extra, struct iovec **_iov) {
PROTECT_ERRNO;
int r, n = 0, i = 0, j;
struct iovec *iov = NULL;
assert(_iov);
if (extra > 0) {
n = MAX(extra * 2, extra + 4);
iov = malloc0(n * sizeof(struct iovec));
if (!iov) {
r = -ENOMEM;
goto fail;
}
i = extra;
}
while (format) {
struct iovec *c;
char *buffer;
va_list aq;
if (i >= n) {
n = MAX(i*2, 4);
c = realloc(iov, n * sizeof(struct iovec));
if (!c) {
r = -ENOMEM;
goto fail;
}
iov = c;
}
va_copy(aq, ap);
if (vasprintf(&buffer, format, aq) < 0) {
va_end(aq);
r = -ENOMEM;
goto fail;
}
va_end(aq);
VA_FORMAT_ADVANCE(format, ap);
IOVEC_SET_STRING(iov[i++], buffer);
format = va_arg(ap, char *);
}
*_iov = iov;
return i;
fail:
for (j = 0; j < i; j++)
free(iov[j].iov_base);
free(iov);
return r;
}
_public_ int sd_journal_send(const char *format, ...) {
int r, i, j;
va_list ap;
struct iovec *iov = NULL;
va_start(ap, format);
i = fill_iovec_sprintf(format, ap, 0, &iov);
va_end(ap);
if (_unlikely_(i < 0)) {
r = i;
goto finish;
}
r = sd_journal_sendv(iov, i);
finish:
for (j = 0; j < i; j++)
free(iov[j].iov_base);
free(iov);
return r;
}
_public_ int sd_journal_sendv(const struct iovec *iov, int n) {
PROTECT_ERRNO;
int fd, buffer_fd;
struct iovec *w;
uint64_t *l;
int i, j = 0;
struct sockaddr_un sa = {
.sun_family = AF_UNIX,
.sun_path = "/run/systemd/journal/socket",
};
struct msghdr mh = {
.msg_name = &sa,
.msg_namelen = offsetof(struct sockaddr_un, sun_path) + strlen(sa.sun_path),
};
ssize_t k;
union {
struct cmsghdr cmsghdr;
uint8_t buf[CMSG_SPACE(sizeof(int))];
} control;
struct cmsghdr *cmsg;
/* We use /dev/shm instead of /tmp here, since we want this to
* be a tmpfs, and one that is available from early boot on
* and where unprivileged users can create files. */
char path[] = "/dev/shm/journal.XXXXXX";
bool have_syslog_identifier = false;
assert_return(iov, -EINVAL);
assert_return(n > 0, -EINVAL);
w = alloca(sizeof(struct iovec) * n * 5 + 3);
l = alloca(sizeof(uint64_t) * n);
for (i = 0; i < n; i++) {
char *c, *nl;
if (_unlikely_(!iov[i].iov_base || iov[i].iov_len <= 1))
return -EINVAL;
c = memchr(iov[i].iov_base, '=', iov[i].iov_len);
if (_unlikely_(!c || c == iov[i].iov_base))
return -EINVAL;
have_syslog_identifier = have_syslog_identifier ||
(c == (char *) iov[i].iov_base + 17 &&
startswith(iov[i].iov_base, "SYSLOG_IDENTIFIER"));
nl = memchr(iov[i].iov_base, '\n', iov[i].iov_len);
if (nl) {
if (_unlikely_(nl < c))
return -EINVAL;
/* Already includes a newline? Bummer, then
* let's write the variable name, then a
* newline, then the size (64bit LE), followed
* by the data and a final newline */
w[j].iov_base = iov[i].iov_base;
w[j].iov_len = c - (char*) iov[i].iov_base;
j++;
IOVEC_SET_STRING(w[j++], "\n");
l[i] = htole64(iov[i].iov_len - (c - (char*) iov[i].iov_base) - 1);
w[j].iov_base = &l[i];
w[j].iov_len = sizeof(uint64_t);
j++;
w[j].iov_base = c + 1;
w[j].iov_len = iov[i].iov_len - (c - (char*) iov[i].iov_base) - 1;
j++;
} else
/* Nothing special? Then just add the line and
* append a newline */
w[j++] = iov[i];
IOVEC_SET_STRING(w[j++], "\n");
}
if (!have_syslog_identifier &&
string_is_safe(program_invocation_short_name)) {
/* Implicitly add program_invocation_short_name, if it
* is not set explicitly. We only do this for
* program_invocation_short_name, and nothing else
* since everything else is much nicer to retrieve
* from the outside. */
IOVEC_SET_STRING(w[j++], "SYSLOG_IDENTIFIER=");
IOVEC_SET_STRING(w[j++], program_invocation_short_name);
IOVEC_SET_STRING(w[j++], "\n");
}
fd = journal_fd();
if (_unlikely_(fd < 0))
return fd;
mh.msg_iov = w;
mh.msg_iovlen = j;
k = sendmsg(fd, &mh, MSG_NOSIGNAL);
if (k >= 0)
return 0;
/* Fail silently if the journal is not available */
if (errno == ENOENT)
return 0;
if (errno != EMSGSIZE && errno != ENOBUFS)
return -errno;
/* Message doesn't fit... Let's dump the data in a temporary
* file and just pass a file descriptor of it to the other
* side */
buffer_fd = mkostemp(path, O_CLOEXEC|O_RDWR);
if (buffer_fd < 0)
return -errno;
if (unlink(path) < 0) {
close_nointr_nofail(buffer_fd);
return -errno;
}
n = writev(buffer_fd, w, j);
if (n < 0) {
close_nointr_nofail(buffer_fd);
return -errno;
}
mh.msg_iov = NULL;
mh.msg_iovlen = 0;
zero(control);
mh.msg_control = &control;
mh.msg_controllen = sizeof(control);
cmsg = CMSG_FIRSTHDR(&mh);
cmsg->cmsg_level = SOL_SOCKET;
cmsg->cmsg_type = SCM_RIGHTS;
cmsg->cmsg_len = CMSG_LEN(sizeof(int));
memcpy(CMSG_DATA(cmsg), &buffer_fd, sizeof(int));
mh.msg_controllen = cmsg->cmsg_len;
k = sendmsg(fd, &mh, MSG_NOSIGNAL);
close_nointr_nofail(buffer_fd);
if (k < 0)
return -errno;
return 0;
}
static int fill_iovec_perror_and_send(const char *message, int skip, struct iovec iov[]) {
PROTECT_ERRNO;
size_t n, k;
k = isempty(message) ? 0 : strlen(message) + 2;
n = 8 + k + 256 + 1;
for (;;) {
char buffer[n];
char* j;
errno = 0;
j = strerror_r(_saved_errno_, buffer + 8 + k, n - 8 - k);
if (errno == 0) {
char error[6 + 10 + 1]; /* for a 32bit value */
if (j != buffer + 8 + k)
memmove(buffer + 8 + k, j, strlen(j)+1);
memcpy(buffer, "MESSAGE=", 8);
if (k > 0) {
memcpy(buffer + 8, message, k - 2);
memcpy(buffer + 8 + k - 2, ": ", 2);
}
snprintf(error, sizeof(error), "ERRNO=%u", _saved_errno_);
char_array_0(error);
IOVEC_SET_STRING(iov[skip+0], "PRIORITY=3");
IOVEC_SET_STRING(iov[skip+1], buffer);
IOVEC_SET_STRING(iov[skip+2], error);
return sd_journal_sendv(iov, skip + 3);
}
if (errno != ERANGE)
return -errno;
n *= 2;
}
}
_public_ int sd_journal_perror(const char *message) {
struct iovec iovec[3];
return fill_iovec_perror_and_send(message, 0, iovec);
}
_public_ int sd_journal_stream_fd(const char *identifier, int priority, int level_prefix) {
union sockaddr_union sa = {
.un.sun_family = AF_UNIX,
.un.sun_path = "/run/systemd/journal/stdout",
};
int fd;
char *header;
size_t l;
ssize_t r;
assert_return(priority >= 0, -EINVAL);
assert_return(priority <= 7, -EINVAL);
fd = socket(AF_UNIX, SOCK_STREAM|SOCK_CLOEXEC, 0);
if (fd < 0)
return -errno;
r = connect(fd, &sa.sa, offsetof(union sockaddr_union, un.sun_path) + strlen(sa.un.sun_path));
if (r < 0) {
close_nointr_nofail(fd);
return -errno;
}
if (shutdown(fd, SHUT_RD) < 0) {
close_nointr_nofail(fd);
return -errno;
}
fd_inc_sndbuf(fd, SNDBUF_SIZE);
if (!identifier)
identifier = "";
l = strlen(identifier);
header = alloca(l + 1 + 1 + 2 + 2 + 2 + 2 + 2);
memcpy(header, identifier, l);
header[l++] = '\n';
header[l++] = '\n'; /* unit id */
header[l++] = '0' + priority;
header[l++] = '\n';
header[l++] = '0' + !!level_prefix;
header[l++] = '\n';
header[l++] = '0';
header[l++] = '\n';
header[l++] = '0';
header[l++] = '\n';
header[l++] = '0';
header[l++] = '\n';
r = loop_write(fd, header, l, false);
if (r < 0) {
close_nointr_nofail(fd);
return (int) r;
}
if ((size_t) r != l) {
close_nointr_nofail(fd);
return -errno;
}
return fd;
}
_public_ int sd_journal_print_with_location(int priority, const char *file, const char *line, const char *func, const char *format, ...) {
int r;
va_list ap;
va_start(ap, format);
r = sd_journal_printv_with_location(priority, file, line, func, format, ap);
va_end(ap);
return r;
}
_public_ int sd_journal_printv_with_location(int priority, const char *file, const char *line, const char *func, const char *format, va_list ap) {
char buffer[8 + LINE_MAX], p[11];
struct iovec iov[5];
char *f;
assert_return(priority >= 0, -EINVAL);
assert_return(priority <= 7, -EINVAL);
assert_return(format, -EINVAL);
snprintf(p, sizeof(p), "PRIORITY=%i", priority & LOG_PRIMASK);
char_array_0(p);
memcpy(buffer, "MESSAGE=", 8);
vsnprintf(buffer+8, sizeof(buffer) - 8, format, ap);
char_array_0(buffer);
/* func is initialized from __func__ which is not a macro, but
* a static const char[], hence cannot easily be prefixed with
* CODE_FUNC=, hence let's do it manually here. */
ALLOCA_CODE_FUNC(f, func);
zero(iov);
IOVEC_SET_STRING(iov[0], buffer);
IOVEC_SET_STRING(iov[1], p);
IOVEC_SET_STRING(iov[2], file);
IOVEC_SET_STRING(iov[3], line);
IOVEC_SET_STRING(iov[4], f);
return sd_journal_sendv(iov, ELEMENTSOF(iov));
}
_public_ int sd_journal_send_with_location(const char *file, const char *line, const char *func, const char *format, ...) {
int r, i, j;
va_list ap;
struct iovec *iov = NULL;
char *f;
va_start(ap, format);
i = fill_iovec_sprintf(format, ap, 3, &iov);
va_end(ap);
if (_unlikely_(i < 0)) {
r = i;
goto finish;
}
ALLOCA_CODE_FUNC(f, func);
IOVEC_SET_STRING(iov[0], file);
IOVEC_SET_STRING(iov[1], line);
IOVEC_SET_STRING(iov[2], f);
r = sd_journal_sendv(iov, i);
finish:
for (j = 3; j < i; j++)
free(iov[j].iov_base);
free(iov);
return r;
}
_public_ int sd_journal_sendv_with_location(
const char *file, const char *line,
const char *func,
const struct iovec *iov, int n) {
struct iovec *niov;
char *f;
assert_return(iov, -EINVAL);
assert_return(n > 0, -EINVAL);
niov = alloca(sizeof(struct iovec) * (n + 3));
memcpy(niov, iov, sizeof(struct iovec) * n);
ALLOCA_CODE_FUNC(f, func);
IOVEC_SET_STRING(niov[n++], file);
IOVEC_SET_STRING(niov[n++], line);
IOVEC_SET_STRING(niov[n++], f);
return sd_journal_sendv(niov, n);
}
_public_ int sd_journal_perror_with_location(
const char *file, const char *line,
const char *func,
const char *message) {
struct iovec iov[6];
char *f;
ALLOCA_CODE_FUNC(f, func);
IOVEC_SET_STRING(iov[0], file);
IOVEC_SET_STRING(iov[1], line);
IOVEC_SET_STRING(iov[2], f);
return fill_iovec_perror_and_send(message, 3, iov);
}
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