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authorDenis Vlasenko <vda.linux@googlemail.com>2008-11-14 21:34:13 +0000
committerDenis Vlasenko <vda.linux@googlemail.com>2008-11-14 21:34:13 +0000
commitb0e5d42d4f3245cb6d7511fc03a09adb82c09783 (patch)
treec74f488e6adb2dc6b89610fbb0dbc52957a73bac
parent142c5cb2a2a7bdceeebec7a55759852bb7ada066 (diff)
downloadbusybox-b0e5d42d4f3245cb6d7511fc03a09adb82c09783.tar.gz
inotify: fix buffer overflow and "unreaped zombies" problem
-rw-r--r--miscutils/inotifyd.c51
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;