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/*
* $Id: cap_sys.c,v 1.1.1.1.4.2 2001/01/16 07:38:25 agmorgan Exp $
*
* Copyright (c) 1997-2000 Andrew G. Morgan <morgan@linux.kernel.org>
*
* This file contains the system calls for getting and setting
* capabilities
*/
#include "libcap.h"
#define __LIBRARY__
#if !defined(__GLIBC__) || __GLIBC__ < 2 || __GLIBC_MINOR__ < 2
#include <linux/unistd.h>
_syscall2(int, capget,
cap_user_header_t, header,
cap_user_data_t, data)
_syscall2(int, capset,
cap_user_header_t, header,
const cap_user_data_t, data)
#endif
/* library defaults to agreeing with the kernel under which it was
compiled */
unsigned int _libcap_kernel_version = 0;
unsigned int _libcap_kernel_features = 0;
/* internally resync the library's idea of the kernel api */
void _libcap_establish_api(void)
{
struct __user_cap_header_struct ch;
struct __user_cap_data_struct cs;
if (_libcap_kernel_version) {
_cap_debug("already identified kernal api 0x%.8x",
_libcap_kernel_version);
return;
}
memset(&ch, 0, sizeof(ch));
memset(&cs, 0, sizeof(cs));
(void) capget(&ch, &cs);
switch (ch.version) {
case 0x19980330:
_libcap_kernel_version = 0x19980330;
_libcap_kernel_features = CAP_FEATURE_PROC|CAP_FEATURE_TO_32;
break;
case 0x20000603:
_libcap_kernel_version = 0x20000603;
_libcap_kernel_features =
CAP_FEATURE_PROC|CAP_FEATURE_FILE|CAP_FEATURE_TO_32;
break;
case 0x20010113:
_libcap_kernel_version = 0x20010113;
_libcap_kernel_features = CAP_FEATURE_PROC|CAP_FEATURE_FILE;
break;
default:
_libcap_kernel_version = 0x00000000;
_libcap_kernel_features = 0x00000000;
}
_cap_debug("(%x) version: %x, features: %x\n", ch.version,
_libcap_kernel_version, _libcap_kernel_features);
}
/*
* This library has been compiled for n=__CAP_BLKS __u32's per cap
* set this may not agree with the kernel that this library is
* running against. As such, we allow for dynamic compensation for
* what the kernel gives/expects with this routine.
*/
int _libcap_n1_to_n2(cap_t cap_d, int n1, int n2)
{
if (!good_cap_t(cap_d)) {
_cap_debug("invalid cap_d");
errno = EINVAL;
return -1;
}
if (n1 > __CAP_BLKS) {
_cap_debug("n1 = %d vs %d --> too large", n1, __CAP_BLKS);
errno = EINVAL;
return -1;
}
if (n2 > __CAP_BLKS) {
_cap_debug("n2 = %d vs %d --> too large", n2, __CAP_BLKS);
errno = EINVAL;
return -1;
}
if (n1 <= 0 || n2 <= 0) {
errno = EINVAL;
return -1;
}
if (n1 > n2) {
/* we need to compress */
__u32 *src, *dest;
int i, j;
src = n1 + (__u32 *) &cap_d->set;
dest = n2 + (__u32 *) &cap_d->set;
for (i=1; i<3; ++i) {
for (j=0; j<n2; ++j) {
dest[j] = src[j];
}
dest += n2;
src += n1;
}
memset(dest, 0, (__CAP_BLKS - n2) * 3 * sizeof(__u32));
} else if (n1 < n2) {
/* we need to expand */
__u32 *src, *dest;
int i, j;
src = 2*n1 + (__u32 *) &cap_d->set;
dest = 2*n2 + (__u32 *) &cap_d->set;
for (i=1; i<3; ++i) {
for (j=0; j<n1; ++j) {
dest[j] = src[j];
}
while (j<n2) {
dest[j++] = 0;
}
dest -= n2;
src -= n1;
}
memset(dest, 0, (__CAP_BLKS - n2) * 3 * sizeof(__u32));
} else {
/* nothing to do */
_cap_debug("called for no reason (%d)", n1);
}
return 0;
}
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