inotifyd: exit if x event happened for all files

 fix FIONREAD parameter type
 fix default mask code
 shrink help text

function                                             old     new   delta
inotifyd_main                                        497     506      +9
packed_usage                                       25446   25431     -15
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 1/1 up/down: 9/-15)              Total: -6 bytes

2 files changed, 36 insertions, 22 deletions

diff --git a/include/usage.h b/include/usage.h
index 9c0c9d761..5223e9e18 100644
--- a/include/usage.h
+++ b/include/usage.h
@@ -1838,16 +1838,11 @@
 "       ::shutdown:/sbin/swapoff -a\n"
 
 #define inotifyd_trivial_usage \
-        "/user/space/agent dir/or/file/being/watched[:mask] ..."
+        "PROG FILE1[:MASK] ..."
 #define inotifyd_full_usage "\n\n" \
-       "Run userspace agent on filesystem changes." \
-     "\nWhen a filesystem event matching the mask occurs" \
-     "\non specified file /user/space/agent is run" \
-     "\nwith the parameters:" \
-     "\n1. actual event(s)" \
-     "\n2. file name" \
-     "\n3. name of subfile (if any)" \
-     "\ninotifyd waits for agent to exit." \
+       "Run PROG on filesystem changes." \
+     "\nWhen a filesystem event matching MASK occurs on FILEn," \
+     "\nPROG <actual_event(s)> <FILEn> [<subfile_name>] is run." \
      "\nEvents:" \
      "\n        a       File is accessed" \
      "\n        c       File is modified" \
@@ -1865,6 +1860,9 @@
      "\n        y       Subfile is moved out of dir" \
      "\n        n       Subfile is created" \
      "\n        d       Subfile is deleted" \
+     "\n" \
+     "\ninotifyd waits for PROG to exit." \
+     "\nWhen x event happens for all FILEs, inotifyd exits" \
 
 #define insmod_trivial_usage \
         USE_FEATURE_2_4_MODULES("[OPTION]... ") "MODULE [symbol=value]..."
diff --git a/miscutils/inotifyd.c b/miscutils/inotifyd.c
index 656510453..fdf2a2c2b 100644
--- a/miscutils/inotifyd.c
+++ b/miscutils/inotifyd.c
@@ -44,6 +44,7 @@ static const char mask_names[] ALIGN1 =
         "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)
@@ -56,27 +57,38 @@ extern int inotify_init(void);
 extern int inotify_add_watch(int fd, const char *path, uint32_t mask);
 
 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)
 {
         int n;
-        unsigned mask = IN_ALL_EVENTS; // assume we want all events
+        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[0] || !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, ':');
+
+                mask = 0x0fff; // assuming we want all non-kernel events
                 // if mask is specified ->
                 if (masks) {
                         *masks = '\0'; // split path and mask
@@ -102,10 +114,9 @@ int inotifyd_main(int argc UNUSED_PARAM, char **argv)
         // do watch
         pfd.events = POLLIN;
         while (1) {
-                ssize_t len;
+                int len;
                 void *buf;
                 struct inotify_event *ie;
-
  again:
                 if (bb_got_signal)
                         break;
@@ -124,6 +135,7 @@ int inotifyd_main(int argc UNUSED_PARAM, char **argv)
                         break;
 
                 // read out all pending events
+                // (NB: len must be int, not ssize_t or long!)
                 xioctl(pfd.fd, FIONREAD, &len);
 #define eventbuf bb_common_bufsiz1
                 ie = buf = (len <= sizeof(eventbuf)) ? eventbuf : xmalloc(len);
@@ -142,11 +154,15 @@ int inotifyd_main(int argc UNUSED_PARAM, char **argv)
                                 }
                                 *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 : "");
+//                                      ie->mask, events, watches[ie->wd], ie->len ? ie->name : "");
                                 args[1] = events;
-                                args[2] = watched[ie->wd];
+                                args[2] = watches[ie->wd];
                                 args[3] = ie->len ? ie->name : NULL;
                                 wait4pid(xspawn((char **)args));
+                                // we are done if all files got final x event
+                                if (ie->mask & 0x8000)
+                                        if (--argc <= 0)
+                                                goto done;
                         }
                         // next event
                         i = sizeof(struct inotify_event) + ie->len;
@@ -155,7 +171,7 @@ int inotifyd_main(int argc UNUSED_PARAM, char **argv)
                 }
                 if (eventbuf != buf)
                         free(buf);
-        }
-
-        return EXIT_SUCCESS;
+        } // while (1)
+ done:
+        return bb_got_signal;
 }