inotify: fix buffer overflow and "unreaped zombies" problem

This commit is contained in:
Denis Vlasenko 2008-11-14 21:34:13 +00:00
parent 142c5cb2a2
commit b0e5d42d4f

View File

@ -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, char **argv) MAIN_EXTERNALLY_VISIBLE;
int inotifyd_main(int argc UNUSED_PARAM, char **argv) int inotifyd_main(int argc UNUSED_PARAM, char **argv)
{ {
int n;
unsigned mask = IN_ALL_EVENTS; // assume we want all events unsigned mask = IN_ALL_EVENTS; // assume we want all events
struct pollfd pfd; struct pollfd pfd;
char **watched = ++argv; // watched name list char **watched = ++argv; // watched name list
@ -69,7 +70,6 @@ int inotifyd_main(int argc UNUSED_PARAM, char **argv)
while (*++argv) { while (*++argv) {
char *path = *argv; char *path = *argv;
char *masks = strchr(path, ':'); char *masks = strchr(path, ':');
int wd; // watch descriptor
// if mask is specified -> // if mask is specified ->
if (masks) { if (masks) {
*masks = '\0'; // split path and mask *masks = '\0'; // split path and mask
@ -83,32 +83,39 @@ int inotifyd_main(int argc UNUSED_PARAM, char **argv)
} }
} }
// add watch // add watch
wd = inotify_add_watch(pfd.fd, path, mask); n = inotify_add_watch(pfd.fd, path, mask);
if (wd < 0) { if (n < 0)
bb_perror_msg_and_die("add watch (%s) failed", path); bb_perror_msg_and_die("add watch (%s) failed", path);
// } else { //bb_error_msg("added %d [%s]:%4X", n, path, mask);
// bb_error_msg("added %d [%s]:%4X", wd, path, mask);
}
} }
// setup signals // setup signals
bb_signals(0 bb_signals(BB_FATAL_SIGS, record_signo);
+ (1 << SIGHUP)
+ (1 << SIGINT)
+ (1 << SIGTERM)
+ (1 << SIGPIPE)
, record_signo);
// do watch // do watch
// pfd.fd = fd;
pfd.events = POLLIN; pfd.events = POLLIN;
while (1) {
while (!bb_got_signal && poll(&pfd, 1, -1) > 0) {
ssize_t len; ssize_t len;
void *buf; void *buf;
struct inotify_event *ie; 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 // read out all pending events
xioctl(pfd.fd, FIONREAD, &len); xioctl(pfd.fd, FIONREAD, &len);
#define eventbuf bb_common_bufsiz1 #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 // process events. N.B. events may vary in length
while (len > 0) { while (len > 0) {
int i; int i;
char events[12]; char events[sizeof(mask_names)];
char *s = events; char *s = events;
unsigned m = ie->mask; unsigned m = ie->mask;
for (i = 0; i < 12; ++i, m >>= 1) { for (i = 0; i < sizeof(mask_names)-1; ++i, m >>= 1) {
if (m & 1) { if (m & 1)
*s++ = mask_names[i]; *s++ = mask_names[i];
}
} }
*s = '\0'; *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[1] = events;
args[2] = watched[ie->wd]; args[2] = watched[ie->wd];
args[3] = ie->len ? ie->name : NULL; args[3] = ie->len ? ie->name : NULL;
xspawn((char **)args); wait4pid(xspawn((char **)args));
// next event // next event
i = sizeof(struct inotify_event) + ie->len; i = sizeof(struct inotify_event) + ie->len;
len -= i; len -= i;