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kernel: Implement wait info count limit in wait_for_objects.

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Since wait_for_objects can wait on sems, threads and ports in addition
to FDs, limiting to RLIMIT_NOFILES as in the select/poll case does not
work. Since space is allocated for the wait objects in kernel memory,
limiting their number to a valid range is still desireable.

The limit is now placed at the sum of max sem, thread and port count
plus RLIMIT_NOFILES.

This also fixes a signed vs. unsigned comparison warning in
check_max_fds introduced in hrev51866.
This commit is contained in:
Michael Lotz 2018-04-06 21:05:45 +02:00
parent 80e9e5f3e7
commit 9c4845e767
1 changed files with 8 additions and 2 deletions
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10
src/system/kernel/wait_for_objects.cpp
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@ -909,9 +909,12 @@ _kern_wait_for_objects(object_wait_info* infos, int numInfos, uint32 flags,
static bool static bool
check_max_fds(int numFDs) check_max_fds(int numFDs)
{ {
if (numFDs <= 0)
return true;
struct io_context *context = get_current_io_context(false); struct io_context *context = get_current_io_context(false);
MutexLocker(&context->io_mutex); MutexLocker(&context->io_mutex);
return numFDs <= context->table_size; return (size_t)numFDs <= context->table_size;
} }
@ -1060,8 +1063,11 @@ _user_wait_for_objects(object_wait_info* userInfos, int numInfos, uint32 flags,
{ {
syscall_restart_handle_timeout_pre(flags, timeout); syscall_restart_handle_timeout_pre(flags, timeout);
if (numInfos < 0) bigtime_t start = system_time();
if (numInfos < 0 || !check_max_fds(numInfos - sem_max_sems()
- port_max_ports() - thread_max_threads())) {
return B_BAD_VALUE; return B_BAD_VALUE;
}
if (numInfos == 0) { if (numInfos == 0) {
// special case: no infos // special case: no infos