You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
71 lines
2.7 KiB
71 lines
2.7 KiB
8 months ago
|
From 1b547e500207a469a533d819db5b7c6c22516ec3 Mon Sep 17 00:00:00 2001
|
||
|
|
From: Lennart Poettering <lennart@poettering.net>
|
||
|
|
Date: Thu, 17 Jan 2019 12:23:21 +0100
|
||
|
|
Subject: [PATCH] fd-util: rework how we determine highest possible fd
|
||
|
|
|
||
|
|
(cherry picked from commit 498e265df1c63212ec1a0991c135877a23f1ba4f)
|
||
|
|
|
||
|
|
Related: RHEL-18302
|
||
|
|
---
|
||
|
|
src/basic/fd-util.c | 37 ++++++++++++++++++++++++++-----------
|
||
|
|
1 file changed, 26 insertions(+), 11 deletions(-)
|
||
|
|
|
||
|
|
diff --git a/src/basic/fd-util.c b/src/basic/fd-util.c
|
||
|
|
index e085dc23b4..fea93d2039 100644
|
||
|
|
--- a/src/basic/fd-util.c
|
||
|
|
+++ b/src/basic/fd-util.c
|
||
|
|
@@ -188,6 +188,27 @@ _pure_ static bool fd_in_set(int fd, const int fdset[], size_t n_fdset) {
|
||
|
|
return false;
|
||
|
|
}
|
||
|
|
|
||
|
|
+static int get_max_fd(void) {
|
||
|
|
+ struct rlimit rl;
|
||
|
|
+ rlim_t m;
|
||
|
|
+
|
||
|
|
+ /* Return the highest possible fd, based RLIMIT_NOFILE, but enforcing FD_SETSIZE-1 as lower boundary
|
||
|
|
+ * and INT_MAX as upper boundary. */
|
||
|
|
+
|
||
|
|
+ if (getrlimit(RLIMIT_NOFILE, &rl) < 0)
|
||
|
|
+ return -errno;
|
||
|
|
+
|
||
|
|
+ m = MAX(rl.rlim_cur, rl.rlim_max);
|
||
|
|
+ if (m < FD_SETSIZE) /* Let's always cover at least 1024 fds */
|
||
|
|
+ return FD_SETSIZE-1;
|
||
|
|
+
|
||
|
|
+ if (m == RLIM_INFINITY || m > INT_MAX) /* Saturate on overflow. After all fds are "int", hence can
|
||
|
|
+ * never be above INT_MAX */
|
||
|
|
+ return INT_MAX;
|
||
|
|
+
|
||
|
|
+ return (int) (m - 1);
|
||
|
|
+}
|
||
|
|
+
|
||
|
|
int close_all_fds(const int except[], size_t n_except) {
|
||
|
|
_cleanup_closedir_ DIR *d = NULL;
|
||
|
|
struct dirent *de;
|
||
|
|
@@ -197,20 +218,14 @@ int close_all_fds(const int except[], size_t n_except) {
|
||
|
|
|
||
|
|
d = opendir("/proc/self/fd");
|
||
|
|
if (!d) {
|
||
|
|
- struct rlimit rl;
|
||
|
|
int fd, max_fd;
|
||
|
|
|
||
|
|
- /* When /proc isn't available (for example in chroots) the fallback is brute forcing through the fd
|
||
|
|
- * table */
|
||
|
|
-
|
||
|
|
- assert_se(getrlimit(RLIMIT_NOFILE, &rl) >= 0);
|
||
|
|
-
|
||
|
|
- if (rl.rlim_max == 0)
|
||
|
|
- return -EINVAL;
|
||
|
|
+ /* When /proc isn't available (for example in chroots) the fallback is brute forcing through
|
||
|
|
+ * the fd table */
|
||
|
|
|
||
|
|
- /* Let's take special care if the resource limit is set to unlimited, or actually larger than the range
|
||
|
|
- * of 'int'. Let's avoid implicit overflows. */
|
||
|
|
- max_fd = (rl.rlim_max == RLIM_INFINITY || rl.rlim_max > INT_MAX) ? INT_MAX : (int) (rl.rlim_max - 1);
|
||
|
|
+ max_fd = get_max_fd();
|
||
|
|
+ if (max_fd < 0)
|
||
|
|
+ return max_fd;
|
||
|
|
|
||
|
|
for (fd = 3; fd >= 0; fd = fd < max_fd ? fd + 1 : -1) {
|
||
|
|
int q;
|