src/journal/journal-send.c

   1 /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
   2
   3 /***
   4   This file is part of systemd.
   5
   6   Copyright 2011 Lennart Poettering
   7
   8   systemd is free software; you can redistribute it and/or modify it
   9   under the terms of the GNU General Public License as published by
  10   the Free Software Foundation; either version 2 of the License, or
  11   (at your option) any later version.
  12
  13   systemd is distributed in the hope that it will be useful, but
  14   WITHOUT ANY WARRANTY; without even the implied warranty of
  15   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  16   General Public License for more details.
  17
  18   You should have received a copy of the GNU General Public License
  19   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  20 ***/
  21
  22 #include <sys/socket.h>
  23 #include <sys/un.h>
  24 #include <errno.h>
  25 #include <stddef.h>
  26
  27 #include "sd-journal.h"
  28 #include "util.h"
  29
  30 /* We open a single fd, and we'll share it with the current process,
  31  * all its threads, and all its subprocesses. This means we need to
  32  * initialize it atomically, and need to operate on it atomically
  33  * never assuming we are the only user */
  34
  35 static int journal_fd(void) {
  36         int fd;
  37         static int fd_plus_one = 0;
  38
  39 retry:
  40         if (fd_plus_one > 0)
  41                 return fd_plus_one - 1;
  42
  43         fd = socket(AF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC, 0);
  44         if (fd < 0)
  45                 return -errno;
  46
  47         if (!__sync_bool_compare_and_swap(&fd_plus_one, 0, fd+1)) {
  48                 close_nointr_nofail(fd);
  49                 goto retry;
  50         }
  51
  52         return fd;
  53 }
  54
  55 int sd_journal_print(const char *format, ...) {
  56         int r;
  57         va_list ap;
  58
  59         va_start(ap, format);
  60         r = sd_journal_printv(format, ap);
  61         va_end(ap);
  62
  63         return r;
  64 }
  65
  66 int sd_journal_printv(const char *format, va_list ap) {
  67         char buffer[8 + LINE_MAX];
  68         struct iovec iov;
  69
  70         memcpy(buffer, "MESSAGE=", 8);
  71         vsnprintf(buffer+8, sizeof(buffer) - 8, format, ap);
  72
  73         char_array_0(buffer);
  74
  75         zero(iov);
  76         IOVEC_SET_STRING(iov, buffer);
  77
  78         return sd_journal_sendv(&iov, 1);
  79 }
  80
  81 int sd_journal_send(const char *format, ...) {
  82         int r, n = 0, i = 0, j;
  83         va_list ap;
  84         struct iovec *iov = NULL;
  85
  86         va_start(ap, format);
  87         while (format) {
  88                 struct iovec *c;
  89                 char *buffer;
  90
  91                 if (i >= n) {
  92                         n = MAX(i*2, 4);
  93                         c = realloc(iov, n * sizeof(struct iovec));
  94                         if (!c) {
  95                                 r = -ENOMEM;
  96                                 goto fail;
  97                         }
  98
  99                         iov = c;
 100                 }
 101
 102                 if (vasprintf(&buffer, format, ap) < 0) {
 103                         r = -ENOMEM;
 104                         goto fail;
 105                 }
 106
 107                 IOVEC_SET_STRING(iov[i++], buffer);
 108
 109                 format = va_arg(ap, char *);
 110         }
 111         va_end(ap);
 112
 113         r = sd_journal_sendv(iov, i);
 114
 115 fail:
 116         for (j = 0; j < i; j++)
 117                 free(iov[j].iov_base);
 118
 119         free(iov);
 120
 121         return r;
 122 }
 123
 124 int sd_journal_sendv(const struct iovec *iov, int n) {
 125         int fd;
 126         struct iovec *w;
 127         uint64_t *l;
 128         int i, j = 0;
 129         struct msghdr mh;
 130         struct sockaddr_un sa;
 131
 132         if (!iov || n <= 0)
 133                 return -EINVAL;
 134
 135         w = alloca(sizeof(struct iovec) * n * 5);
 136         l = alloca(sizeof(uint64_t) * n);
 137
 138         for (i = 0; i < n; i++) {
 139                 char *c, *nl;
 140
 141                 c = memchr(iov[i].iov_base, '=', iov[i].iov_len);
 142                 if (!c)
 143                         return -EINVAL;
 144
 145                 nl = memchr(iov[i].iov_base, '\n', iov[i].iov_len);
 146                 if (nl) {
 147                         if (nl < c)
 148                                 return -EINVAL;
 149
 150                         /* Already includes a newline? Bummer, then
 151                          * let's write the variable name, then a
 152                          * newline, then the size (64bit LE), followed
 153                          * by the data and a final newline */
 154
 155                         w[j].iov_base = iov[i].iov_base;
 156                         w[j].iov_len = c - (char*) iov[i].iov_base;
 157                         j++;
 158
 159                         IOVEC_SET_STRING(w[j++], "\n");
 160
 161                         l[i] = htole64(iov[i].iov_len - (c - (char*) iov[i].iov_base) - 1);
 162                         w[j].iov_base = &l[i];
 163                         w[j].iov_len = sizeof(uint64_t);
 164                         j++;
 165
 166                         w[j].iov_base = c + 1;
 167                         w[j].iov_len = iov[i].iov_len - (c - (char*) iov[i].iov_base) - 1;
 168                         j++;
 169
 170                 } else
 171                         /* Nothing special? Then just add the line and
 172                          * append a newline */
 173                         w[j++] = iov[i];
 174
 175                 IOVEC_SET_STRING(w[j++], "\n");
 176         }
 177
 178         fd = journal_fd();
 179         if (fd < 0)
 180                 return fd;
 181
 182         zero(sa);
 183         sa.sun_family = AF_UNIX;
 184         strncpy(sa.sun_path,"/run/systemd/journal", sizeof(sa.sun_path));
 185
 186         zero(mh);
 187         mh.msg_name = &sa;
 188         mh.msg_namelen = offsetof(struct sockaddr_un, sun_path) + strlen(sa.sun_path);
 189         mh.msg_iov = w;
 190         mh.msg_iovlen = j;
 191
 192         if (sendmsg(fd, &mh, MSG_NOSIGNAL) < 0)
 193                 return -errno;
 194
 195         return 0;
 196 }