src/liblxc/monitor.c

   1 /*
   2  * lxc: linux Container library
   3  *
   4  * (C) Copyright IBM Corp. 2007, 2008
   5  *
   6  * Authors:
   7  * Daniel Lezcano <dlezcano at fr.ibm.com>
   8  *
   9  * This library is free software; you can redistribute it and/or
  10  * modify it under the terms of the GNU Lesser General Public
  11  * License as published by the Free Software Foundation; either
  12  * version 2.1 of the License, or (at your option) any later version.
  13  *
  14  * This library is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  17  * Lesser General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU Lesser General Public
  20  * License along with this library; if not, write to the Free Software
  21  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  22  */
  23 #include <stdio.h>
  24 #include <errno.h>
  25 #include <unistd.h>
  26 #include <string.h>
  27 #include <stdlib.h>
  28 #include <fcntl.h>
  29 #include <sys/types.h>
  30 #include <sys/stat.h>
  31 #include <sys/param.h>
  32 #include <sys/inotify.h>
  33 #include <sys/socket.h>
  34 #include <sys/un.h>
  35 #include <netinet/in.h>
  36 #include <net/if.h>
  37 #include <lxc.h>
  38
  39 #ifndef UNIX_PATH_MAX
  40 #define UNIX_PATH_MAX 108
  41 #endif
  42
  43 int lxc_monitor(const char *name, int output_fd)
  44 {
  45         char path[MAXPATHLEN];
  46         int err = -1, nfd, wfd, state;
  47
  48         nfd = inotify_init();
  49         if (nfd < 0) {
  50                 lxc_log_syserror("failed to initialize inotify");
  51                 return -1;
  52         }
  53
  54         snprintf(path, MAXPATHLEN, LXCPATH "/%s/state", name);
  55
  56         wfd = inotify_add_watch(nfd, path, IN_DELETE_SELF|IN_CLOSE_WRITE);
  57         if (wfd < 0) {
  58                 lxc_log_syserror("failed to add a watch on %s", path);
  59                 goto out;
  60         }
  61
  62         for(;;) {
  63                 struct inotify_event evt;
  64
  65                 if (read(nfd, &evt, sizeof(evt)) < 0) {
  66                         lxc_log_syserror("failed to read inotify event");
  67                         goto out;
  68                 }
  69
  70                 if (evt.mask & IN_CLOSE_WRITE) {
  71
  72                         state = lxc_getstate(name);
  73                         if (state < 0) {
  74                                 lxc_log_error("failed to get the state for %s",
  75                                               name);
  76                                 goto out;
  77                         }
  78
  79                         if (write(output_fd, &state, sizeof(state)) < 0) {
  80                                 lxc_log_syserror("failed to send state to %d",
  81                                                  output_fd);
  82                                 goto out;
  83                         }
  84                         continue;
  85                 }
  86
  87                 if (evt.mask & IN_DELETE_SELF) {
  88                         close(output_fd);
  89                         err = 0;
  90                         goto out;
  91                 }
  92
  93                 lxc_log_error("unknown evt for inotity (%d)", evt.mask);
  94                 goto out;
  95         }
  96
  97 out:
  98         inotify_rm_watch(nfd, wfd);
  99         close(nfd);
 100         return err;
 101 }
 102
 103 void lxc_monitor_send_state(const char *name, lxc_state_t state)
 104 {
 105         int fd;
 106         struct sockaddr_un addr;
 107
 108         fd = socket(PF_UNIX, SOCK_DGRAM, 0);
 109         if (fd < 0)
 110                 lxc_log_syserror("failed to create notification socket");
 111
 112         memset(&addr, 0, sizeof(addr));
 113         addr.sun_family = AF_UNIX;
 114         snprintf(addr.sun_path, UNIX_PATH_MAX, LXCPATH "/%s/notification", name);
 115
 116         sendto(fd, &state, sizeof(state), 0,
 117                (const struct sockaddr *)&addr, sizeof(addr));
 118
 119         close(fd);
 120 }
 121
 122 void lxc_monitor_cleanup(const char *name)
 123 {
 124         char path[UNIX_PATH_MAX];
 125         snprintf(path, UNIX_PATH_MAX, LXCPATH "/%s/notification", name);
 126         unlink(path);
 127 }
 128
 129 int lxc_monitor_open(const char *name)
 130 {
 131         int fd;
 132         struct sockaddr_un addr;
 133
 134         fd = socket(PF_UNIX, SOCK_DGRAM, 0);
 135         if (fd < 0) {
 136                 lxc_log_syserror("failed to create notification socket");
 137                 return -1;
 138         }
 139
 140         memset(&addr, 0, sizeof(addr));
 141
 142         addr.sun_family = AF_UNIX;
 143         snprintf(addr.sun_path, UNIX_PATH_MAX, LXCPATH "/%s/notification", name);
 144         unlink(addr.sun_path);
 145
 146         if (bind(fd, (const struct sockaddr *)&addr, sizeof(addr))) {
 147                 lxc_log_syserror("failed to bind to '%s'", addr.sun_path);
 148                 return -1;
 149         }
 150
 151         return fd;
 152 }
 153
 154 int lxc_monitor_read(int fd, lxc_state_t *state)
 155 {
 156         int ret;
 157
 158         ret = recv(fd, state, sizeof(*state), 0);
 159         if (ret < 0) {
 160                 lxc_log_syserror("failed to received state");
 161                 return -1;
 162         }
 163
 164         return ret;
 165 }
 166
 167 int lxc_monitor_close(int fd)
 168 {
 169         return close(fd);
 170 }