*
* Copyright (C) 2008 by Vladimir Dronnikov <dronnikov@gmail.com>
*
- * Licensed under GPLv2, see file LICENSE in this tarball for details.
+ * 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 occured on specified file (or directory)
+ * 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)
* $2. file (or directory) name
*
* See below for mask names explanation.
*/
+//config:config INOTIFYD
+//config: bool "inotifyd (3.5 kb)"
+//config: default n # doesn't build on Knoppix 5
+//config: help
+//config: Simple inotify daemon. Reports filesystem changes. Requires
+//config: kernel >= 2.6.13
+
+//applet:IF_INOTIFYD(APPLET(inotifyd, BB_DIR_SBIN, BB_SUID_DROP))
+
+//kbuild:lib-$(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: "\n a File is accessed"
+//usage: "\n c File is modified"
+//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: "\n x File can't be watched anymore"
+//usage: "\nIf watching a directory:"
+//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 <linux/inotify.h>
-
-static volatile smallint signalled;
-
-static void signal_handler(int signo)
-{
- signalled = signo;
-}
+#include "common_bufsiz.h"
+#include <sys/inotify.h>
static const char mask_names[] ALIGN1 =
"a" // 0x00000001 File was accessed
"c" // 0x00000002 File was modified
"e" // 0x00000004 Metadata changed
- "w" // 0x00000008 Writtable file was closed
- "0" // 0x00000010 Unwrittable file closed
+ "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
"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)
;
-
-extern int inotify_init(void);
-extern int inotify_add_watch(int fd, const char *path, uint32_t mask);
+enum {
+ MASK_BITS = sizeof(mask_names) - 1
+};
int inotifyd_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
-int inotifyd_main(int argc UNUSED_PARAM, char **argv)
+int inotifyd_main(int argc, char **argv)
{
- unsigned mask = IN_ALL_EVENTS; // assume we want all events
+ int n;
+ unsigned mask;
struct pollfd pfd;
- char **watched = ++argv; // watched name list
- const char *args[] = { *argv, NULL, NULL, NULL, NULL };
+ 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])
+ 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_perror_msg_and_die("no kernel support");
- // setup watched
+ // setup watches
while (*++argv) {
char *path = *argv;
char *masks = strchr(path, ':');
- int wd; // watch descriptor
+
+ 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) {
- int i = strchr(mask_names, *masks) - mask_names;
- if (i >= 0) {
- mask |= (1 << i);
- }
+ const char *found;
+ found = memchr(mask_names, *masks, MASK_BITS);
+ if (found)
+ mask |= (1 << (found - mask_names));
}
}
// add watch
- wd = inotify_add_watch(pfd.fd, path, mask);
- if (wd < 0) {
+ n = inotify_add_watch(pfd.fd, path, mask);
+ if (n < 0)
bb_perror_msg_and_die("add watch (%s) failed", path);
-// } else {
-// bb_error_msg("added %d [%s]:%4X", wd, path, mask);
- }
+ //bb_error_msg("added %d [%s]:%4X", n, path, mask);
}
// setup signals
- bb_signals(0
- + (1 << SIGHUP)
- + (1 << SIGINT)
- + (1 << SIGTERM)
- + (1 << SIGPIPE)
- , signal_handler);
+ bb_signals(BB_FATAL_SIGS, record_signo);
// do watch
-
-// pfd.fd = fd;
pfd.events = POLLIN;
-
- while (!signalled && poll(&pfd, 1, -1) > 0) {
- ssize_t len;
+ 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
- xioctl(pfd.fd, FIONREAD, &len);
+ // (NB: len must be int, not ssize_t or long!)
#define eventbuf bb_common_bufsiz1
- ie = buf = (len <= sizeof(eventbuf)) ? eventbuf : xmalloc(len);
+ 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;
- char events[12];
- char *s = events;
- unsigned m = ie->mask;
-
- for (i = 0; i < 12; ++i, m >>= 1) {
- if (m & 1) {
- *s++ = mask_names[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);
}
}
- *s = '\0';
-// bb_error_msg("exec %s %08X\t%s\t%s\t%s", agent, ie->mask, events, watched[ie->wd], ie->len ? ie->name : "");
- args[1] = events;
- args[2] = watched[ie->wd];
- args[3] = ie->len ? ie->name : NULL;
- xspawn((char **)args);
// next event
i = sizeof(struct inotify_event) + ie->len;
len -= i;
}
if (eventbuf != buf)
free(buf);
- }
-
- return EXIT_SUCCESS;
+ } // while (1)
+ done:
+ return bb_got_signal;
}
projects / oweals / busybox.git / blobdiff