/* vi: set sw=4 ts=4: */ /* * simple inotify daemon * reports filesystem changes via userspace agent * * Copyright (C) 2008 by Vladimir Dronnikov * * Licensed under GPLv2, see file LICENSE in this source tree. */ /* * Use as follows: * # inotifyd /user/space/agent dir/or/file/being/watched[:mask] ... * * When a filesystem event matching the specified mask is occurred on specified file (or directory) * a userspace agent is spawned and given the following parameters: * $1. actual event(s) * $2. file (or directory) name * $3. name of subfile (if any), in case of watching a directory * * E.g. inotifyd ./dev-watcher /dev:n * * ./dev-watcher can be, say: * #!/bin/sh * echo "We have new device in here! Hello, $3!" * * See below for mask names explanation. */ //config:config INOTIFYD //config: bool "inotifyd (3.6 kb)" //config: default n # doesn't build on Knoppix 5 //config: help //config: Simple inotify daemon. Reports filesystem changes. Requires //config: kernel >= 2.6.13 //applet:IF_INOTIFYD(APPLET(inotifyd, BB_DIR_SBIN, BB_SUID_DROP)) //kbuild:lib-$(CONFIG_INOTIFYD) += inotifyd.o //usage:#define inotifyd_trivial_usage //usage: "PROG FILE1[:MASK]..." //usage:#define inotifyd_full_usage "\n\n" //usage: "Run PROG on filesystem changes." //usage: "\nWhen a filesystem event matching MASK occurs on FILEn," //usage: "\nPROG ACTUAL_EVENTS FILEn [SUBFILE] is run." //usage: "\nIf PROG is -, events are sent to stdout." //usage: "\nEvents:" //usage: IF_NOT_PLATFORM_MINGW32( //usage: "\n a File is accessed" //usage: ) //usage: "\n c File is modified" //usage: IF_NOT_PLATFORM_MINGW32( //usage: "\n e Metadata changed" //usage: "\n w Writable file is closed" //usage: "\n 0 Unwritable file is closed" //usage: "\n r File is opened" //usage: "\n D File is deleted" //usage: "\n M File is moved" //usage: "\n u Backing fs is unmounted" //usage: "\n o Event queue overflowed" //usage: ) //usage: "\n x File can't be watched anymore" //usage: IF_NOT_PLATFORM_MINGW32( //usage: "\nIf watching a directory:" //usage: ) //usage: "\n y Subfile is moved into dir" //usage: "\n m Subfile is moved out of dir" //usage: "\n n Subfile is created" //usage: "\n d Subfile is deleted" //usage: "\n" //usage: "\ninotifyd waits for PROG to exit." //usage: "\nWhen x event happens for all FILEs, inotifyd exits." #include "libbb.h" #include "common_bufsiz.h" #include #if !ENABLE_PLATFORM_MINGW32 static const char mask_names[] ALIGN1 = "a" // 0x00000001 File was accessed "c" // 0x00000002 File was modified "e" // 0x00000004 Metadata changed "w" // 0x00000008 Writable file was closed "0" // 0x00000010 Unwritable file closed "r" // 0x00000020 File was opened "m" // 0x00000040 File was moved from X "y" // 0x00000080 File was moved to Y "n" // 0x00000100 Subfile was created "d" // 0x00000200 Subfile was deleted "D" // 0x00000400 Self was deleted "M" // 0x00000800 Self was moved "\0" // 0x00001000 (unused) // Kernel events, always reported: "u" // 0x00002000 Backing fs was unmounted "o" // 0x00004000 Event queued overflowed "x" // 0x00008000 File is no longer watched (usually deleted) ; enum { MASK_BITS = sizeof(mask_names) - 1 }; int inotifyd_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; int inotifyd_main(int argc, char **argv) { int n; unsigned mask; struct pollfd pfd; char **watches; // names of files being watched const char *args[5]; // sanity check: agent and at least one watch must be given if (!argv[1] || !argv[2]) bb_show_usage(); argv++; // inotify_add_watch will number watched files // starting from 1, thus watches[0] is unimportant, // and 1st file name is watches[1]. watches = argv; args[0] = *argv; args[4] = NULL; argc -= 2; // number of files we watch // open inotify pfd.fd = inotify_init(); if (pfd.fd < 0) bb_simple_perror_msg_and_die("no kernel support"); // setup watches while (*++argv) { char *path = *argv; char *masks = strchr(path, ':'); mask = 0x0fff; // assuming we want all non-kernel events // if mask is specified -> if (masks) { *masks = '\0'; // split path and mask // convert mask names to mask bitset mask = 0; while (*++masks) { const char *found; found = memchr(mask_names, *masks, MASK_BITS); if (found) mask |= (1 << (found - mask_names)); } } // add watch n = inotify_add_watch(pfd.fd, path, mask); if (n < 0) bb_perror_msg_and_die("add watch (%s) failed", path); //bb_error_msg("added %d [%s]:%4X", n, path, mask); } // setup signals bb_signals(BB_FATAL_SIGS, record_signo); // do watch pfd.events = POLLIN; while (1) { int len; void *buf; struct inotify_event *ie; again: if (bb_got_signal) break; n = poll(&pfd, 1, -1); // Signal interrupted us? if (n < 0 && errno == EINTR) goto again; // Under Linux, above if() is not necessary. // Non-fatal signals, e.g. SIGCHLD, when set to SIG_DFL, // are not interrupting poll(). // Thus we can just break if n <= 0 (see below), // because EINTR will happen only on SIGTERM et al. // But this might be not true under other Unixes, // and is generally way too subtle to depend on. if (n <= 0) // strange error? break; // read out all pending events // (NB: len must be int, not ssize_t or long!) #define eventbuf bb_common_bufsiz1 setup_common_bufsiz(); xioctl(pfd.fd, FIONREAD, &len); ie = buf = (len <= COMMON_BUFSIZE) ? eventbuf : xmalloc(len); len = full_read(pfd.fd, buf, len); // process events. N.B. events may vary in length while (len > 0) { int i; // cache relevant events mask unsigned m = ie->mask & ((1 << MASK_BITS) - 1); if (m) { char events[MASK_BITS + 1]; char *s = events; for (i = 0; i < MASK_BITS; ++i, m >>= 1) { if ((m & 1) && (mask_names[i] != '\0')) *s++ = mask_names[i]; } *s = '\0'; if (LONE_CHAR(args[0], '-')) { /* "inotifyd - FILE": built-in echo */ printf(ie->len ? "%s\t%s\t%s\n" : "%s\t%s\n", events, watches[ie->wd], ie->name); fflush(stdout); } else { // bb_error_msg("exec %s %08X\t%s\t%s\t%s", args[0], // ie->mask, events, watches[ie->wd], ie->len ? ie->name : ""); args[1] = events; args[2] = watches[ie->wd]; args[3] = ie->len ? ie->name : NULL; spawn_and_wait((char **)args); } // we are done if all files got final x event if (ie->mask & 0x8000) { if (--argc <= 0) goto done; inotify_rm_watch(pfd.fd, ie->wd); } } // next event i = sizeof(struct inotify_event) + ie->len; len -= i; ie = (void*)((char*)ie + i); } if (eventbuf != buf) free(buf); } // while (1) done: return bb_got_signal; } #else /* ENABLE_PLATFORM_MINGW32 */ /* * Order is important: the indices match the values taken by the * Action member of the FILE_NOTIFY_INFORMATION structure, including * the undocumented zero value when the directory itself is deleted. */ static const char mask_names[] ALIGN1 = "x" // File is no longer watched (usually deleted) "n" // Subfile was created "d" // Subfile was deleted "c" // File was modified "m" // File was moved from X "y" // File was moved to Y ; enum { MASK_BITS = sizeof(mask_names) - 1 }; static const unsigned mask_values[] = { 0x000, // File is no longer watched (usually deleted) 0x003, // Subfile was created 0x003, // Subfile was deleted 0x1fc, // File was modified (everything except create/delete/move) 0x003, // File was moved from X 0x003, // File was moved to Y }; struct watch { HANDLE hdir; HANDLE hevent; DWORD mask; // notification filter DWORD bits; // events to report OVERLAPPED overlap; const char *dirname; char buf[2048]; }; static void run_agent(const char *agent, FILE_NOTIFY_INFORMATION *info, struct watch *w) { int len; char filename[MAX_PATH]; char event[2]; const char *args[5]; memset(filename, 0, sizeof(filename)); len = WideCharToMultiByte(CP_ACP, 0, info->FileName, info->FileNameLength/2, filename, sizeof(filename), NULL, NULL); if (info->Action >= 0 && info->Action < 6 && ((1 << info->Action) & w->bits)) { event[0] = mask_names[info->Action]; event[1] = '\0'; if (LONE_CHAR(agent, '-')) { /* "inotifyd - FILE": built-in echo */ printf(len ? "%s\t%s\t%s\n" : "%s\t%s\n", event, w->dirname, filename); fflush(stdout); } else { args[0] = agent; args[1] = event; args[2] = w->dirname; args[3] = len ? filename : NULL; args[4] = NULL; spawn_and_wait((char **)args); } } } static BOOL start_watch(struct watch *w) { DWORD nret; memset(w->buf, 0, sizeof(w->buf)); memset(&w->overlap, 0, sizeof(OVERLAPPED)); w->overlap.hEvent = w->hevent; ResetEvent(w->hevent); return ReadDirectoryChangesW(w->hdir, w->buf, sizeof(w->buf), FALSE, w->mask, &nret, &w->overlap, NULL); } int inotifyd_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; int inotifyd_main(int argc, char **argv) { int n; unsigned mask, bits; const char *agent; HANDLE *hevent; struct watch *watch; // sanity check: agent and at least one watch must be given if (!argv[1] || !argv[2]) bb_show_usage(); argv++; agent = *argv; argc -= 2; // number of files we watch watch = (struct watch *)xzalloc(argc * sizeof(struct watch)); hevent = (HANDLE *)xzalloc(argc * sizeof(HANDLE)); // setup watches for (n = 0; *++argv; ++n) { char *masks; masks = strrchr(*argv, ':'); // don't confuse a drive prefix with a mask if (masks && masks != (*argv)+1) *masks = '\0'; mask = 0x01ff; // assuming we want all notifications bits = 0x3f; // assuming we want to report everything // if mask is specified -> if (masks && *masks == '\0') { // convert names to notification filter and report bitmask mask = bits = 0; while (*++masks) { const char *found; found = memchr(mask_names, *masks, MASK_BITS); if (found) { mask |= mask_values[(found - mask_names)]; bits |= (1 << (found - mask_names)); } } } if (mask == 0) bb_error_msg_and_die("%s: invalid mask\n", *argv); if (!is_directory(*argv, FALSE)) bb_error_msg_and_die("%s: not a directory", *argv); watch[n].hdir = CreateFile(*argv, GENERIC_READ|FILE_LIST_DIRECTORY, FILE_SHARE_READ|FILE_SHARE_WRITE|FILE_SHARE_DELETE, NULL, OPEN_EXISTING, FILE_FLAG_BACKUP_SEMANTICS|FILE_FLAG_OVERLAPPED, NULL); if (watch[n].hdir == INVALID_HANDLE_VALUE) break; watch[n].dirname = *argv; watch[n].mask = mask; watch[n].bits = bits; watch[n].hevent = hevent[n] = CreateEvent(NULL, TRUE, FALSE, NULL); if (!start_watch(watch+n)) break; } if (*argv != NULL) { errno = err_win_to_posix(); bb_perror_msg_and_die("add watch (%s) failed", *argv); } while (1) { DWORD status; status = WaitForMultipleObjects(n, hevent, FALSE, INFINITE); if (WAIT_OBJECT_0 <= status && status < WAIT_OBJECT_0 + n) { FILE_NOTIFY_INFORMATION *info; int index = status - WAIT_OBJECT_0; int offset = 0; struct watch *w = watch + index; int got_zero = 0; do { info = (FILE_NOTIFY_INFORMATION *)(w->buf + offset); got_zero += (info->Action == 0); run_agent(agent, info, w); offset += info->NextEntryOffset; } while (info->NextEntryOffset); if (!start_watch(w)) { // directory was deleted? int i, count; if (!got_zero) { // we haven't seen an 'x' event, fake one memset(info, 0, sizeof(FILE_NOTIFY_INFORMATION)); run_agent(agent, info, w); } // mark watch as dead, terminate if all are dead w->mask = 0; for (count = i = 0; i