Module Name: src
Committed By: martin
Date: Sun Mar 8 09:47:28 UTC 2020
Modified Files:
src/sys/kern [netbsd-8]: sys_select.c
Log Message:
Pull up following revision(s) (requested by mlelstv in ticket #1515):
sys/kern/sys_select.c: revision 1.42-1.45
PR/54158: Anthony Mallet: poll(2) does not allow polling all possible fds
(hardcoded limit to 1000 + #<open-fds>). Changed to limit by the max of
the resource limit of open descriptors and the above.
Remove the slop code. Suggested by mrg@
Use the max limit (aka maxfiles or the moral equivalent of OPEN_MAX) which
makes poll(2) align with the Posix documentation (which allows EINVAL if
nfds > OPEN_MAX). From: Anthony Mallet
Add slop of 1000 and explain why.
To generate a diff of this commit:
cvs rdiff -u -r1.40 -r1.40.2.1 src/sys/kern/sys_select.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/kern/sys_select.c
diff -u src/sys/kern/sys_select.c:1.40 src/sys/kern/sys_select.c:1.40.2.1
--- src/sys/kern/sys_select.c:1.40 Thu Jun 1 02:45:13 2017
+++ src/sys/kern/sys_select.c Sun Mar 8 09:47:28 2020
@@ -1,4 +1,4 @@
-/* $NetBSD: sys_select.c,v 1.40 2017/06/01 02:45:13 chs Exp $ */
+/* $NetBSD: sys_select.c,v 1.40.2.1 2020/03/08 09:47:28 martin Exp $ */
/*-
* Copyright (c) 2007, 2008, 2009, 2010 The NetBSD Foundation, Inc.
@@ -84,7 +84,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: sys_select.c,v 1.40 2017/06/01 02:45:13 chs Exp $");
+__KERNEL_RCSID(0, "$NetBSD: sys_select.c,v 1.40.2.1 2020/03/08 09:47:28 martin Exp $");
#include <sys/param.h>
#include <sys/systm.h>
@@ -488,15 +488,28 @@ pollcommon(register_t *retval, struct po
int error;
size_t ni;
- if (nfds > 1000 + curlwp->l_fd->fd_dt->dt_nfiles) {
+ if (nfds > curlwp->l_proc->p_rlimit[RLIMIT_NOFILE].rlim_max + 1000) {
/*
- * Either the user passed in a very sparse 'fds' or junk!
- * The kmem_alloc() call below would be bad news.
- * We could process the 'fds' array in chunks, but that
+ * Prevent userland from causing over-allocation.
+ * Raising the default limit too high can still cause
+ * a lot of memory to be allocated, but this also means
+ * that the file descriptor array will also be large.
+ *
+ * To reduce the memory requirements here, we could
+ * process the 'fds' array in chunks, but that
* is a lot of code that isn't normally useful.
* (Or just move the copyin/out into pollscan().)
+ *
* Historically the code silently truncated 'fds' to
* dt_nfiles entries - but that does cause issues.
+ *
+ * Using the max limit equivalent to sysctl
+ * kern.maxfiles is the moral equivalent of OPEN_MAX
+ * as specified by POSIX.
+ *
+ * We add a slop of 1000 in case the resource limit was
+ * changed after opening descriptors or the same descriptor
+ * was specified more than once.
*/
return EINVAL;
}
