journal: implicitly add code location to all messages logged with the native interface

This logic can be turned off by defining SD_JOURNAL_SUPPRESS_LOCATION
before including sd-journal.h.

This also saves/restores errno in all logging functions, in order to be
useful as logging calls without side-effects.

This also adds a couple of __unlikely__ around the early checks in the
logging calls, in order to minimize the runtime impact.

3 files changed, 250 insertions, 28 deletions

diff --git a/src/journal/journal-send.c b/src/journal/journal-send.c
index b5b4fbfa0d..32e94af91f 100644
--- a/src/journal/journal-send.c
+++ b/src/journal/journal-send.c
@@ -26,6 +26,8 @@
 #include <unistd.h>
 #include <fcntl.h>
 
+#define SD_JOURNAL_SUPPRESS_LOCATION
+
 #include "sd-journal.h"
 #include "util.h"
 #include "socket-util.h"
@@ -94,12 +96,26 @@ _public_ int sd_journal_printv(int priority, const char *format, va_list ap) {
         return sd_journal_sendv(iov, 2);
 }
 
-_public_ int sd_journal_send(const char *format, ...) {
-        int r, n = 0, i = 0, j;
-        va_list ap;
+static int fill_iovec_sprintf(const char *format, va_list ap, int extra, struct iovec **_iov) {
+        int r, n = 0, i, j;
         struct iovec *iov = NULL;
+        int saved_errno;
+
+        assert(_iov);
+        saved_errno = errno;
+
+        if (extra > 0) {
+                n = MAX(extra * 2, extra + 4);
+                iov = malloc0(n * sizeof(struct iovec));
+                if (!iov) {
+                        r = -ENOMEM;
+                        goto fail;
+                }
+
+                i = extra;
+        } else
+                i = 0;
 
-        va_start(ap, format);
         while (format) {
                 struct iovec *c;
                 char *buffer;
@@ -124,11 +140,39 @@ _public_ int sd_journal_send(const char *format, ...) {
 
                 format = va_arg(ap, char *);
         }
+
+        *_iov = iov;
+
+        errno = saved_errno;
+        return i;
+
+fail:
+        for (j = 0; j < i; j++)
+                free(iov[j].iov_base);
+
+        free(iov);
+
+        errno = saved_errno;
+        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);
 
-fail:
+finish:
         for (j = 0; j < i; j++)
                 free(iov[j].iov_base);
 
@@ -141,10 +185,11 @@ _public_ int sd_journal_sendv(const struct iovec *iov, int n) {
         int fd, buffer_fd;
         struct iovec *w;
         uint64_t *l;
-        int i, j = 0;
+        int r, i, j = 0;
         struct msghdr mh;
         struct sockaddr_un sa;
         ssize_t k;
+        int saved_errno;
         union {
                 struct cmsghdr cmsghdr;
                 uint8_t buf[CMSG_SPACE(sizeof(int))];
@@ -155,27 +200,37 @@ _public_ int sd_journal_sendv(const struct iovec *iov, int n) {
          * and where unprivileged users can create files. */
         char path[] = "/dev/shm/journal.XXXXXX";
 
-        if (!iov || n <= 0)
+        if (_unlikely_(!iov))
+                return -EINVAL;
+
+        if (_unlikely_(n <= 0))
                 return -EINVAL;
 
+        saved_errno = errno;
+
         w = alloca(sizeof(struct iovec) * n * 5);
         l = alloca(sizeof(uint64_t) * n);
 
         for (i = 0; i < n; i++) {
                 char *c, *nl;
 
-                if (!iov[i].iov_base ||
-                    iov[i].iov_len <= 1)
-                        return -EINVAL;
+                if (_unlikely_(!iov[i].iov_base || iov[i].iov_len <= 1)) {
+                        r = -EINVAL;
+                        goto finish;
+                }
 
                 c = memchr(iov[i].iov_base, '=', iov[i].iov_len);
-                if (!c || c == iov[i].iov_base)
-                        return -EINVAL;
+                if (_unlikely_(!c || c == iov[i].iov_base)) {
+                        r = -EINVAL;
+                        goto finish;
+                }
 
                 nl = memchr(iov[i].iov_base, '\n', iov[i].iov_len);
                 if (nl) {
-                        if (nl < c)
-                                return -EINVAL;
+                        if (_unlikely_(nl < c)) {
+                                r = -EINVAL;
+                                goto finish;
+                        }
 
                         /* Already includes a newline? Bummer, then
                          * let's write the variable name, then a
@@ -206,8 +261,10 @@ _public_ int sd_journal_sendv(const struct iovec *iov, int n) {
         }
 
         fd = journal_fd();
-        if (fd < 0)
-                return fd;
+        if (_unlikely_(fd < 0)) {
+                r = fd;
+                goto finish;
+        }
 
         zero(sa);
         sa.sun_family = AF_UNIX;
@@ -220,29 +277,37 @@ _public_ int sd_journal_sendv(const struct iovec *iov, int n) {
         mh.msg_iovlen = j;
 
         k = sendmsg(fd, &mh, MSG_NOSIGNAL);
-        if (k >= 0)
-                return 0;
+        if (k >= 0) {
+                r = 0;
+                goto finish;
+        }
 
-        if (errno != EMSGSIZE && errno != ENOBUFS)
-                return -errno;
+        if (errno != EMSGSIZE && errno != ENOBUFS) {
+                r = -errno;
+                goto finish;
+        }
 
         /* 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 (buffer_fd < 0) {
+                r = -errno;
+                goto finish;
+        }
 
         if (unlink(path) < 0) {
                 close_nointr_nofail(buffer_fd);
-                return -errno;
+                r = -errno;
+                goto finish;
         }
 
         n = writev(buffer_fd, w, j);
-        if (n < 0)  {
+        if (n < 0) {
                 close_nointr_nofail(buffer_fd);
-                return -errno;
+                r = -errno;
+                goto finish;
         }
 
         mh.msg_iov = NULL;
@@ -263,10 +328,17 @@ _public_ int sd_journal_sendv(const struct iovec *iov, int n) {
         k = sendmsg(fd, &mh, MSG_NOSIGNAL);
         close_nointr_nofail(buffer_fd);
 
-        if (k < 0)
-                return -errno;
+        if (k < 0) {
+                r = -errno;
+                goto finish;
+        }
+
+        r = 0;
+
+finish:
+        errno = saved_errno;
 
-        return 0;
+        return r;
 }
 
 _public_ int sd_journal_stream_fd(const char *identifier, int priority, int level_prefix) {
@@ -332,3 +404,113 @@ _public_ int sd_journal_stream_fd(const char *identifier, int priority, int leve
 
         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;
+        size_t fl;
+
+        if (priority < 0 || priority > 7)
+                return -EINVAL;
+
+        if (_unlikely_(!format))
+                return -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. */
+        fl = strlen(func);
+        f = alloca(fl + 10);
+        memcpy(f, "CODE_FUNC=", 10);
+        memcpy(f + 10, func, fl + 1);
+
+        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;
+        size_t fl;
+
+        va_start(ap, format);
+        i = fill_iovec_sprintf(format, ap, 3, &iov);
+        va_end(ap);
+
+        if (_unlikely_(i < 0)) {
+                r = i;
+                goto finish;
+        }
+
+        fl = strlen(func);
+        f = alloca(fl + 10);
+        memcpy(f, "CODE_FUNC=", 10);
+        memcpy(f + 10, func, fl + 1);
+
+        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;
+        size_t fl;
+
+        if (_unlikely_(!iov))
+                return -EINVAL;
+
+        if (_unlikely_(n <= 0))
+                return -EINVAL;
+
+        niov = alloca(sizeof(struct iovec) * (n + 3));
+        memcpy(niov, iov, sizeof(struct iovec) * n);
+
+        fl = strlen(func);
+        f = alloca(fl + 10);
+        memcpy(f, "CODE_FUNC=", 10);
+        memcpy(f + 10, func, fl + 1);
+
+        IOVEC_SET_STRING(niov[n++], file);
+        IOVEC_SET_STRING(niov[n++], line);
+        IOVEC_SET_STRING(niov[n++], f);
+
+        return sd_journal_sendv(niov, n);
+}
diff --git a/src/journal/libsystemd-journal.sym b/src/journal/libsystemd-journal.sym
index 7653880e8f..cd434aea26 100644
--- a/src/journal/libsystemd-journal.sym
+++ b/src/journal/libsystemd-journal.sym
@@ -43,3 +43,11 @@ global:
 local:
         *;
 };
+
+LIBSYSTEMD_JOURNAL_45 {
+global:
+        sd_journal_print_with_location;
+        sd_journal_printv_with_location;
+        sd_journal_send_with_location;
+        sd_journal_sendv_with_location;
+} LIBSYSTEMD_JOURNAL_38;
diff --git a/src/journal/test-journal-send.c b/src/journal/test-journal-send.c
new file mode 100644
index 0000000000..2f9987dcde
--- /dev/null
+++ b/src/journal/test-journal-send.c
@@ -0,0 +1,32 @@
+/*-*- 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 General Public License as published by
+  the Free Software Foundation; either version 2 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
+  General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include <systemd/sd-journal.h>
+
+int main(int argc, char *argv[]) {
+        sd_journal_print(LOG_INFO, "piepapo");
+
+        sd_journal_send("MESSAGE=foobar",
+                        "VALUE=%i", 7,
+                        NULL);
+
+        return 0;
+}