inotify: fix buffer overflow and "unreaped zombies" problem

1 files changed, 29 insertions, 22 deletions

diff --git a/miscutils/inotifyd.c b/miscutils/inotifyd.c
index 5ac47386a..0c4b06784 100644
--- a/miscutils/inotifyd.c
+++ b/miscutils/inotifyd.c
@@ -51,6 +51,7 @@ 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 n;
         unsigned mask = IN_ALL_EVENTS; // assume we want all events
         struct pollfd pfd;
         char **watched = ++argv; // watched name list
@@ -69,7 +70,6 @@ int inotifyd_main(int argc UNUSED_PARAM, char **argv)
         while (*++argv) {
                 char *path = *argv;
                 char *masks = strchr(path, ':');
-                int wd; // watch descriptor
                 // if mask is specified ->
                 if (masks) {
                         *masks = '\0'; // split path and mask
@@ -83,32 +83,39 @@ int inotifyd_main(int argc UNUSED_PARAM, char **argv)
                         }
                 }
                 // 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)
-                , record_signo);
+        bb_signals(BB_FATAL_SIGS, record_signo);
 
         // do watch
-
-//      pfd.fd = fd;
         pfd.events = POLLIN;
-
-        while (!bb_got_signal && poll(&pfd, 1, -1) > 0) {
+        while (1) {
                 ssize_t 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);
 #define eventbuf bb_common_bufsiz1
@@ -117,21 +124,21 @@ 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[12];
+                        char events[sizeof(mask_names)];
                         char *s = events;
                         unsigned m = ie->mask;
 
-                        for (i = 0; i < 12; ++i, m >>= 1) {
-                                if (m & 1) {
+                        for (i = 0; i < sizeof(mask_names)-1; ++i, m >>= 1) {
+                                if (m & 1)
                                         *s++ = mask_names[i];
-                                }
                         }
                         *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 : "");
+                        //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);
+                        wait4pid(xspawn((char **)args));
                         // next event
                         i = sizeof(struct inotify_event) + ie->len;
                         len -= i;