mirror of
git://git.kernel.org/pub/scm/linux/kernel/git/xiang/erofs.git
synced 2026-10-31 14:23:49 +01:00
Ian Rogers
bac74dcbd4
strerror() has thread safety issues, strerror_r() requires stack allocated buffers. Code in perf has already been using the "%m" formatting flag that is a widely support glibc extension to print the current errno's description. Expand the usage of this formatting flag and remove usage of strerror()/strerror_r(). Signed-off-by: Ian Rogers <[email protected]> Acked-by: Namhyung Kim <[email protected]> Cc: Adrian Hunter <[email protected]> Cc: Alexander Shishkin <[email protected]> Cc: Alexandre Ghiti <[email protected]> Cc: Blake Jones <[email protected]> Cc: Chun-Tse Shao <[email protected]> Cc: Dmitriy Vyukov <[email protected]> Cc: Dr. David Alan Gilbert <[email protected]> Cc: Haibo Xu <[email protected]> Cc: Howard Chu <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: Jiri Olsa <[email protected]> Cc: Leo Yan <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Stephen Brennan <[email protected]> Cc: Thomas Falcon <[email protected]> Cc: Yunseong Kim <[email protected]> Cc: Zhongqiu Han <[email protected]> Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
49 lines
1.2 KiB
C
49 lines
1.2 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Capability utilities
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*/
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#include "cap.h"
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#include "debug.h"
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#include <errno.h>
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#include <string.h>
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#include <sys/syscall.h>
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#include <unistd.h>
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#define MAX_LINUX_CAPABILITY_U32S _LINUX_CAPABILITY_U32S_3
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bool perf_cap__capable(int cap, bool *used_root)
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{
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struct __user_cap_header_struct header = {
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.version = _LINUX_CAPABILITY_VERSION_3,
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.pid = 0,
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};
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struct __user_cap_data_struct data[MAX_LINUX_CAPABILITY_U32S] = {};
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__u32 cap_val;
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*used_root = false;
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while (syscall(SYS_capget, &header, &data[0]) == -1) {
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/* Retry, first attempt has set the header.version correctly. */
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if (errno == EINVAL && header.version != _LINUX_CAPABILITY_VERSION_3 &&
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header.version == _LINUX_CAPABILITY_VERSION_1)
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continue;
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pr_debug2("capget syscall failed (%m) fall back on root check\n");
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*used_root = true;
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return geteuid() == 0;
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}
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/* Extract the relevant capability bit. */
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if (cap >= 32) {
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if (header.version == _LINUX_CAPABILITY_VERSION_3) {
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cap_val = data[1].effective;
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} else {
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/* Capability beyond 32 is requested but only 32 are supported. */
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return false;
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}
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} else {
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cap_val = data[0].effective;
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}
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return (cap_val & (1 << (cap & 0x1f))) != 0;
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}
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