From a09a42cd83a0365b5b52dfdcce20b3c9932be801 Mon Sep 17 00:00:00 2001
From: Denis Vlasenko <vda.linux@googlemail.com>
Date: Mon, 17 Nov 2008 22:19:18 +0000
Subject: [PATCH] inotify: add x, o, and u events

---
 include/usage.h      | 14 +++++++++-----
 miscutils/inotifyd.c | 45 ++++++++++++++++++++++++++------------------
 2 files changed, 36 insertions(+), 23 deletions(-)

diff --git a/include/usage.h b/include/usage.h
index 67b2acf72..9c0c9d761 100644
--- a/include/usage.h
+++ b/include/usage.h
@@ -1846,7 +1846,7 @@
      "\nwith the parameters:" \
      "\n1. actual event(s)" \
      "\n2. file name" \
-     "\n3. name of subfile (if any), in case of watching a directory" \
+     "\n3. name of subfile (if any)" \
      "\ninotifyd waits for agent to exit." \
      "\nEvents:" \
      "\n	a	File is accessed" \
@@ -1855,12 +1855,16 @@
      "\n	w	Writtable file is closed" \
      "\n	0	Unwrittable file is closed" \
      "\n	r	File is opened" \
-     "\n	m	File is moved from X" \
-     "\n	y	File is moved to Y" \
+     "\n	D	File is deleted" \
+     "\n	M	File is moved" \
+     "\n	u	Backing fs is unmounted" \
+     "\n	o	Event queue overflowed" \
+     "\n	x	File can't be watched anymore" \
+     "\nIf watching a directory:" \
+     "\n	m	Subfile is moved into dir" \
+     "\n	y	Subfile is moved out of dir" \
      "\n	n	Subfile is created" \
      "\n	d	Subfile is deleted" \
-     "\n	D	Self is deleted" \
-     "\n	M	Self is moved" \
 
 #define insmod_trivial_usage \
 	USE_FEATURE_2_4_MODULES("[OPTION]... ") "MODULE [symbol=value]..."
diff --git a/miscutils/inotifyd.c b/miscutils/inotifyd.c
index 2a1355156..656510453 100644
--- a/miscutils/inotifyd.c
+++ b/miscutils/inotifyd.c
@@ -43,7 +43,14 @@ static const char mask_names[] ALIGN1 =
 	"d"	// 0x00000200	Subfile was deleted
 	"D"	// 0x00000400	Self was deleted
 	"M"	// 0x00000800	Self was moved
+	"\0"	// 0x00001000   (unused)
+	"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
+};
 
 extern int inotify_init(void);
 extern int inotify_add_watch(int fd, const char *path, uint32_t mask);
@@ -76,10 +83,10 @@ int inotifyd_main(int argc UNUSED_PARAM, char **argv)
 			// 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
@@ -124,21 +131,23 @@ int inotifyd_main(int argc UNUSED_PARAM, char **argv)
 		// process events. N.B. events may vary in length
 		while (len > 0) {
 			int i;
-			char events[sizeof(mask_names)];
-			char *s = events;
-			unsigned m = ie->mask;
-
-			for (i = 0; i < sizeof(mask_names)-1; ++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';
+//				bb_error_msg("exec %s %08X\t%s\t%s\t%s", args[0],
+//					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;
+				wait4pid(xspawn((char **)args));
 			}
-			*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;
-			wait4pid(xspawn((char **)args));
 			// next event
 			i = sizeof(struct inotify_event) + ie->len;
 			len -= i;