diff options
| author | David Herrmann <dh.herrmann@gmail.com> | 2014-12-29 13:24:35 +0100 |
|---|---|---|
| committer | David Herrmann <dh.herrmann@gmail.com> | 2014-12-29 14:05:38 +0100 |
| commit | 80b4378314cf62148fd053e97018cc5c78dd6af6 (patch) | |
| tree | 002fd8517de717e0b5d952fa8c5765450da71fdd /src/shared | |
| parent | 2f0af4e120385e6078c96189f4a4d0cce0e12a3a (diff) | |
capability: use /proc/sys/kernel/cap_last_cap
This file was introduced with linux-3.2, use it instead of probing for it
via prctl(PR_CAPBSET_READ).
For now, keep the old code for backwards compat. We can drop it once 3.2
is our lowest requirement.
The test-cap-list code is extended to verify cap_last_cap() is the same as
we'd get via prctl probing and /proc.
Diffstat (limited to 'src/shared')
| -rw-r--r-- | src/shared/capability.c | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/src/shared/capability.c b/src/shared/capability.c index 65d7e038a..b1be04380 100644 --- a/src/shared/capability.c +++ b/src/shared/capability.c @@ -54,11 +54,25 @@ int have_effective_cap(int value) { unsigned long cap_last_cap(void) { static thread_local unsigned long saved; static thread_local bool valid = false; + _cleanup_free_ char *content = NULL; unsigned long p; + int r; if (valid) return saved; + /* available since linux-3.2 */ + r = read_one_line_file("/proc/sys/kernel/cap_last_cap", &content); + if (r >= 0) { + r = safe_atolu(content, &p); + if (r >= 0) { + saved = p; + valid = true; + return p; + } + } + + /* fall back to syscall-probing for pre linux-3.2 */ p = (unsigned long) CAP_LAST_CAP; if (prctl(PR_CAPBSET_READ, p) < 0) { |