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libressl portable code 1
/*
* issetugid implementation for Linux
* Public domain
*/
#include <errno.h>
#include <gnu/libc-version.h>
#include <string.h>
#include <sys/types.h>
#include <unistd.h>
/*
* Linux-specific glibc 2.16+ interface for determining if a process was
* launched setuid/setgid or with additional capabilities.
*/
#ifdef HAVE_GETAUXVAL
#include <sys/auxv.h>
#endif
int issetugid(void)
{
#ifdef HAVE_GETAUXVAL
/*
* The API for glibc < 2.19 does not indicate if there is an error with
* getauxval. While it should not be the case that any 2.6 or greater
* kernel ever does not supply AT_SECURE, an emulated software environment
* might rewrite the aux vector.
*
* See https://sourceware.org/bugzilla/show_bug.cgi?id=15846
*
* Perhaps this code should just read the aux vector itself, so we have
* backward-compatibility and error handling in older glibc versions.
* info: http://lwn.net/Articles/519085/
*
*/
const char *glcv = gnu_get_libc_version();
if (strverscmp(glcv, "2.19") >= 0) {
errno = 0;
if (getauxval(AT_SECURE) == 0) {
if (errno != ENOENT) {
return 0;
}
}
}
#endif
return 1;
}
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