| /* dnsmasq is Copyright (c) 2000-2014 Simon Kelley |
| |
| This program 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; version 2 dated June, 1991, or |
| (at your option) version 3 dated 29 June, 2007. |
| |
| This program 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 this program. If not, see <http://www.gnu.org/licenses/>. |
| */ |
| |
| #include "dnsmasq.h" |
| #ifdef HAVE_LINUX_NETWORK |
| |
| #include <sys/inotify.h> |
| |
| #ifdef HAVE_DHCP |
| static void check_for_dhcp_inotify(struct inotify_event *in, time_t now); |
| #endif |
| |
| |
| /* the strategy is to set a inotify on the directories containing |
| resolv files, for any files in the directory which are close-write |
| or moved into the directory. |
| |
| When either of those happen, we look to see if the file involved |
| is actually a resolv-file, and if so, call poll-resolv with |
| the "force" argument, to ensure it's read. |
| |
| This adds one new error condition: the directories containing |
| all specified resolv-files must exist at start-up, even if the actual |
| files don't. |
| */ |
| |
| static char *inotify_buffer; |
| #define INOTIFY_SZ (sizeof(struct inotify_event) + NAME_MAX + 1) |
| |
| void inotify_dnsmasq_init() |
| { |
| struct resolvc *res; |
| |
| inotify_buffer = safe_malloc(INOTIFY_SZ); |
| daemon->inotifyfd = inotify_init1(IN_NONBLOCK | IN_CLOEXEC); |
| |
| if (daemon->inotifyfd == -1) |
| die(_("failed to create inotify: %s"), NULL, EC_MISC); |
| |
| for (res = daemon->resolv_files; res; res = res->next) |
| { |
| char *d = NULL, *path; |
| |
| if (!(path = realpath(res->name, NULL))) |
| { |
| /* realpath will fail if the file doesn't exist, but |
| dnsmasq copes with missing files, so fall back |
| and assume that symlinks are not in use in that case. */ |
| if (errno == ENOENT) |
| path = res->name; |
| else |
| die(_("cannot cannonicalise resolv-file %s: %s"), res->name, EC_MISC); |
| } |
| |
| if ((d = strrchr(path, '/'))) |
| { |
| *d = 0; /* make path just directory */ |
| res->wd = inotify_add_watch(daemon->inotifyfd, path, IN_CLOSE_WRITE | IN_MOVED_TO); |
| |
| res->file = d+1; /* pointer to filename */ |
| *d = '/'; |
| |
| if (res->wd == -1 && errno == ENOENT) |
| die(_("directory %s for resolv-file is missing, cannot poll"), res->name, EC_MISC); |
| |
| if (res->wd == -1) |
| die(_("failed to create inotify for %s: %s"), res->name, EC_MISC); |
| } |
| } |
| } |
| |
| int inotify_check(time_t now) |
| { |
| int hit = 0; |
| |
| while (1) |
| { |
| int rc; |
| char *p; |
| struct resolvc *res; |
| struct inotify_event *in; |
| |
| while ((rc = read(daemon->inotifyfd, inotify_buffer, INOTIFY_SZ)) == -1 && errno == EINTR); |
| |
| if (rc <= 0) |
| break; |
| |
| for (p = inotify_buffer; rc - (p - inotify_buffer) >= (int)sizeof(struct inotify_event); p += sizeof(struct inotify_event) + in->len) |
| { |
| in = (struct inotify_event*)p; |
| |
| for (res = daemon->resolv_files; res; res = res->next) |
| if (res->wd == in->wd && in->len != 0 && strcmp(res->file, in->name) == 0) |
| hit = 1; |
| |
| #ifdef HAVE_DHCP |
| if (daemon->dhcp || daemon->doing_dhcp6) |
| check_for_dhcp_inotify(in, now); |
| #endif |
| } |
| } |
| return hit; |
| } |
| |
| #ifdef HAVE_DHCP |
| /* initialisation for dhcp-hostdir. Set inotify watch for each directory, and read pre-existing files */ |
| void set_dhcp_inotify(void) |
| { |
| struct hostsfile *ah; |
| |
| for (ah = daemon->inotify_hosts; ah; ah = ah->next) |
| { |
| DIR *dir_stream = NULL; |
| struct dirent *ent; |
| struct stat buf; |
| |
| if (stat(ah->fname, &buf) == -1 || !(S_ISDIR(buf.st_mode))) |
| { |
| my_syslog(LOG_ERR, _("bad directory in dhcp-hostsdir %s"), ah->fname); |
| continue; |
| } |
| |
| if (!(ah->flags & AH_WD_DONE)) |
| { |
| ah->wd = inotify_add_watch(daemon->inotifyfd, ah->fname, IN_CLOSE_WRITE | IN_MOVED_TO); |
| ah->flags |= AH_WD_DONE; |
| } |
| /* Read contents of dir _after_ calling add_watch, in the ho[e of avoiding |
| a race which misses files being added as we start */ |
| if (ah->wd == -1 || !(dir_stream = opendir(ah->fname))) |
| { |
| my_syslog(LOG_ERR, _("failed to create inotify for %s"), ah->fname); |
| continue; |
| } |
| |
| while ((ent = readdir(dir_stream))) |
| { |
| size_t lendir = strlen(ah->fname); |
| size_t lenfile = strlen(ent->d_name); |
| char *path; |
| |
| /* ignore emacs backups and dotfiles */ |
| if (lenfile == 0 || |
| ent->d_name[lenfile - 1] == '~' || |
| (ent->d_name[0] == '#' && ent->d_name[lenfile - 1] == '#') || |
| ent->d_name[0] == '.') |
| continue; |
| |
| if ((path = whine_malloc(lendir + lenfile + 2))) |
| { |
| strcpy(path, ah->fname); |
| strcat(path, "/"); |
| strcat(path, ent->d_name); |
| |
| /* ignore non-regular files */ |
| if (stat(path, &buf) != -1 && S_ISREG(buf.st_mode)) |
| option_read_hostsfile(path); |
| |
| free(path); |
| } |
| } |
| } |
| } |
| |
| static void check_for_dhcp_inotify(struct inotify_event *in, time_t now) |
| { |
| struct hostsfile *ah; |
| |
| /* ignore emacs backups and dotfiles */ |
| if (in->len == 0 || |
| in->name[in->len - 1] == '~' || |
| (in->name[0] == '#' && in->name[in->len - 1] == '#') || |
| in->name[0] == '.') |
| return; |
| |
| for (ah = daemon->inotify_hosts; ah; ah = ah->next) |
| if (ah->wd == in->wd) |
| { |
| size_t lendir = strlen(ah->fname); |
| char *path; |
| |
| if ((path = whine_malloc(lendir + in->len + 2))) |
| { |
| strcpy(path, ah->fname); |
| strcat(path, "/"); |
| strcat(path, in->name); |
| |
| if (option_read_hostsfile(path)) |
| { |
| /* Propogate the consequences of loading a new dhcp-host */ |
| dhcp_update_configs(daemon->dhcp_conf); |
| lease_update_from_configs(); |
| lease_update_file(now); |
| lease_update_dns(1); |
| } |
| |
| free(path); |
| } |
| |
| return; |
| } |
| } |
| |
| #endif /* DHCP */ |
| |
| #endif /* LINUX_NETWORK */ |
| |