// SPDX-License-Identifier: GPL-2.0/* * Capability utilities */ #include "cap.h"#include "debug.h"#include <errno.h>#include <string.h>#include <sys/syscall.h>#include <unistd.h> #define MAX_LINUX_CAPABILITY_U32S _LINUX_CAPABILITY_U32S_3 bool perf_cap__capable(int cap){	struct __user_cap_header_struct header = {		.version = _LINUX_CAPABILITY_VERSION_3,		.pid = 0,	};	struct __user_cap_data_struct data[MAX_LINUX_CAPABILITY_U32S] = {};	__u32 cap_val; 	while (syscall(SYS_capget, &header, &data[0]) == -1) {		/* Retry, first attempt has set the header.version correctly. */		if (errno == EINVAL && header.version != _LINUX_CAPABILITY_VERSION_3 &&		    header.version == _LINUX_CAPABILITY_VERSION_1)			continue; 		pr_debug2("capget syscall failed (%m) fall back on root check\n");		return geteuid() == 0;	} 	/* Extract the relevant capability bit. */	if (cap >= 32) {		if (header.version == _LINUX_CAPABILITY_VERSION_3) {			cap_val = data[1].effective;		} else {			/* Capability beyond 32 is requested but only 32 are supported. */			return false;		}	} else {		cap_val = data[0].effective;	}	return (cap_val & (1 << (cap & 0x1f))) != 0;}