path: root/Documentation/sysctl
diff options
authorDan Ballard <dan@mindstab.net>2011-10-31 17:11:20 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2011-10-31 17:30:53 -0700
commit73efc0394e148d0e15583e13712637831f926720 (patch)
tree896c58a85f520bcccae4f16647cfb0f1ecd2c08e /Documentation/sysctl
parent4ff819515b203f937cc6c8a0215a37a68d1ee71f (diff)
kernel/sysctl.c: add cap_last_cap to /proc/sys/kernel
Userspace needs to know the highest valid capability of the running kernel, which right now cannot reliably be retrieved from the header files only. The fact that this value cannot be determined properly right now creates various problems for libraries compiled on newer header files which are run on older kernels. They assume capabilities are available which actually aren't. libcap-ng is one example. And we ran into the same problem with systemd too. Now the capability is exported in /proc/sys/kernel/cap_last_cap. [akpm@linux-foundation.org: make cap_last_cap const, per Ulrich] Signed-off-by: Dan Ballard <dan@mindstab.net> Cc: Randy Dunlap <rdunlap@xenotime.net> Cc: Ingo Molnar <mingo@elte.hu> Cc: Lennart Poettering <lennart@poettering.net> Cc: Kay Sievers <kay.sievers@vrfy.org> Cc: Ulrich Drepper <drepper@akkadia.org> Cc: James Morris <jmorris@namei.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'Documentation/sysctl')
1 files changed, 8 insertions, 0 deletions
diff --git a/Documentation/sysctl/kernel.txt b/Documentation/sysctl/kernel.txt
index 704e474a93d..1f2463671a1 100644
--- a/Documentation/sysctl/kernel.txt
+++ b/Documentation/sysctl/kernel.txt
@@ -24,6 +24,7 @@ show up in /proc/sys/kernel:
- bootloader_type [ X86 only ]
- bootloader_version [ X86 only ]
- callhome [ S390 only ]
+- cap_last_cap
- core_pattern
- core_pipe_limit
- core_uses_pid
@@ -155,6 +156,13 @@ on has a service contract with IBM.
+Highest valid capability of the running kernel. Exports
+CAP_LAST_CAP from the kernel.
core_pattern is used to specify a core dumpfile pattern name.