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Systemd/src/journal/journal-send.c

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17 KiB
C
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/* SPDX-License-Identifier: LGPL-2.1+ */
#include <errno.h>
#include <fcntl.h>
#include <printf.h>
#include <stddef.h>
#include <sys/un.h>
#include <unistd.h>
#define SD_JOURNAL_SUPPRESS_LOCATION
#include "sd-journal.h"
#include "alloc-util.h"
#include "errno-util.h"
#include "fd-util.h"
#include "io-util.h"
#include "fileio.h"
#include "memfd-util.h"
#include "socket-util.h"
#include "stdio-util.h"
#include "string-util.h"
#include "tmpfile-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 = newa(char, _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)) {
safe_close(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) {
char p[STRLEN("PRIORITY=") + DECIMAL_STR_MAX(int) + 1];
char sbuf[LINE_MAX + 8] = "MESSAGE=";
struct iovec iov[2];
int len;
va_list aq;
char *buffer = sbuf;
assert_return(priority >= 0, -EINVAL);
assert_return(priority <= 7, -EINVAL);
assert_return(format, -EINVAL);
xsprintf(p, "PRIORITY=%i", priority & LOG_PRIMASK);
va_copy(aq, ap);
len = vsnprintf(buffer + 8, LINE_MAX, format, aq);
va_end(aq);
if (len >= (int)LONG_LINE_MAX - 8)
return -ENOBUFS;
/* Allocate large buffer to accommodate big message */
if (len >= LINE_MAX) {
int rlen;
buffer = alloca(len + 9);
memcpy(buffer, "MESSAGE=", 8);
rlen = vsnprintf(buffer + 8, len + 1, format, ap);
assert(len == rlen);
}
/* Strip trailing whitespace, keep prefix whitespace. */
(void) strstrip(buffer);
/* Suppress empty lines */
if (isempty(buffer + 8))
return 0;
iov[0] = IOVEC_MAKE_STRING(buffer);
iov[1] = IOVEC_MAKE_STRING(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);
(void) strstrip(buffer); /* strip trailing whitespace, keep prefixing whitespace */
iov[i++] = IOVEC_MAKE_STRING(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, r;
_cleanup_close_ int buffer_fd = -1;
struct iovec *w;
uint64_t *l;
int i, j = 0;
static const union sockaddr_union sa = {
.un.sun_family = AF_UNIX,
.un.sun_path = "/run/systemd/journal/socket",
};
struct msghdr mh = {
.msg_name = (struct sockaddr*) &sa.sa,
.msg_namelen = SOCKADDR_UN_LEN(sa.un),
};
ssize_t k;
bool have_syslog_identifier = false;
bool seal = true;
assert_return(iov, -EINVAL);
assert_return(n > 0, -EINVAL);
w = newa(struct iovec, n * 5 + 3);
l = newa(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++] = IOVEC_MAKE(iov[i].iov_base, c - (char*) iov[i].iov_base);
w[j++] = IOVEC_MAKE_STRING("\n");
l[i] = htole64(iov[i].iov_len - (c - (char*) iov[i].iov_base) - 1);
w[j++] = IOVEC_MAKE(&l[i], sizeof(uint64_t));
w[j++] = IOVEC_MAKE(c + 1, iov[i].iov_len - (c - (char*) iov[i].iov_base) - 1);
} else
/* Nothing special? Then just add the line and
* append a newline */
w[j++] = iov[i];
w[j++] = IOVEC_MAKE_STRING("\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. */
w[j++] = IOVEC_MAKE_STRING("SYSLOG_IDENTIFIER=");
w[j++] = IOVEC_MAKE_STRING(program_invocation_short_name);
w[j++] = IOVEC_MAKE_STRING("\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 (!IN_SET(errno, EMSGSIZE, ENOBUFS))
return -errno;
/* Message doesn't fit... Let's dump the data in a memfd or
* temporary file and just pass a file descriptor of it to the
* other side.
*
* For the temporary files 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. */
buffer_fd = memfd_new(NULL);
if (buffer_fd < 0) {
if (buffer_fd == -ENOSYS) {
buffer_fd = open_tmpfile_unlinkable("/dev/shm", O_RDWR | O_CLOEXEC);
if (buffer_fd < 0)
return buffer_fd;
seal = false;
} else
return buffer_fd;
}
n = writev(buffer_fd, w, j);
if (n < 0)
return -errno;
if (seal) {
r = memfd_set_sealed(buffer_fd);
if (r < 0)
return r;
}
r = send_one_fd_sa(fd, buffer_fd, mh.msg_name, mh.msg_namelen, 0);
if (r == -ENOENT)
/* Fail silently if the journal is not available */
return 0;
return r;
}
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[STRLEN("ERRNO=") + DECIMAL_STR_MAX(int) + 1];
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);
}
xsprintf(error, "ERRNO=%i", _saved_errno_);
assert_cc(3 == LOG_ERR);
iov[skip+0] = IOVEC_MAKE_STRING("PRIORITY=3");
iov[skip+1] = IOVEC_MAKE_STRING(buffer);
iov[skip+2] = IOVEC_MAKE_STRING(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) {
static const union sockaddr_union sa = {
.un.sun_family = AF_UNIX,
.un.sun_path = "/run/systemd/journal/stdout",
};
_cleanup_close_ int fd = -1;
char *header;
size_t l;
int 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, SOCKADDR_UN_LEN(sa.un));
if (r < 0)
return -errno;
if (shutdown(fd, SHUT_RD) < 0)
return -errno;
(void) fd_inc_sndbuf(fd, SNDBUF_SIZE);
identifier = strempty(identifier);
l = strlen(identifier);
header = newa(char, 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)
return r;
return TAKE_FD(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 p[STRLEN("PRIORITY=") + DECIMAL_STR_MAX(int) + 1];
char sbuf[LINE_MAX + 8] = "MESSAGE=";
struct iovec iov[5];
char *f;
int len;
char *buffer = sbuf;
va_list aq;
assert_return(priority >= 0, -EINVAL);
assert_return(priority <= 7, -EINVAL);
assert_return(format, -EINVAL);
xsprintf(p, "PRIORITY=%i", priority & LOG_PRIMASK);
va_copy(aq, ap);
len = vsnprintf(buffer + 8, LINE_MAX, format, aq);
va_end(aq);
if (len >= (int)LONG_LINE_MAX - 8)
return -ENOBUFS;
/* Allocate large buffer to accommodate big message */
if (len >= LINE_MAX) {
int rlen;
buffer = alloca(len + 9);
memcpy(buffer, "MESSAGE=", 8);
rlen = vsnprintf(buffer + 8, len + 1, format, ap);
assert(len == rlen);
}
/* Strip trailing whitespace, keep prefixing whitespace */
(void) strstrip(buffer);
/* Suppress empty lines */
if (isempty(buffer + 8))
return 0;
/* 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);
iov[0] = IOVEC_MAKE_STRING(buffer);
iov[1] = IOVEC_MAKE_STRING(p);
iov[2] = IOVEC_MAKE_STRING(file);
iov[3] = IOVEC_MAKE_STRING(line);
iov[4] = IOVEC_MAKE_STRING(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, ...) {
_cleanup_free_ struct iovec *iov = NULL;
int r, i, j;
va_list ap;
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);
iov[0] = IOVEC_MAKE_STRING(file);
iov[1] = IOVEC_MAKE_STRING(line);
iov[2] = IOVEC_MAKE_STRING(f);
r = sd_journal_sendv(iov, i);
finish:
for (j = 3; j < i; j++)
free(iov[j].iov_base);
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 = newa(struct iovec, n + 3);
memcpy(niov, iov, sizeof(struct iovec) * n);
ALLOCA_CODE_FUNC(f, func);
niov[n++] = IOVEC_MAKE_STRING(file);
niov[n++] = IOVEC_MAKE_STRING(line);
niov[n++] = IOVEC_MAKE_STRING(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);
iov[0] = IOVEC_MAKE_STRING(file);
iov[1] = IOVEC_MAKE_STRING(line);
iov[2] = IOVEC_MAKE_STRING(f);
return fill_iovec_perror_and_send(message, 3, iov);
}
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