testsuite: improve coverage of shared/util.h

[thirdparty/kmod.git] / testsuite / uname.c

/*
 * Copyright (C) 2012-2013  ProFUSION embedded systems
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, see <http://www.gnu.org/licenses/>.
 */

#include <dlfcn.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/utsname.h>

#include "testsuite.h"

TS_EXPORT int uname(struct utsname *u)
{
	static void *nextlib = NULL;
	static int (*nextlib_uname)(struct utsname *u);
	const char *release;
	int err;
	size_t sz;

	if (nextlib == NULL) {
#ifdef RTLD_NEXT
		nextlib = RTLD_NEXT;
#else
		nextlib = dlopen("libc.so.6", RTLD_LAZY);
#endif
		nextlib_uname = dlsym(nextlib, "uname");
	}

	err = nextlib_uname(u);
	if (err < 0)
		return err;

	if (!environ)
		/*
		 * probably called from within glibc before main(); unsafe
		 * to call getenv()
		 */
		return 0;

	release = getenv(S_TC_UNAME_R);
	if (release == NULL) {
		fprintf(stderr, "TRAP uname(): missing export %s?\n",
							S_TC_UNAME_R);
		return 0;
	}

	sz = strlen(release) + 1;
	if (sz > sizeof(u->release)) {
		fprintf(stderr, "uname(): sizeof release (%s) "
				"is greater than available space: %zu",
				release, sizeof(u->release));
		errno = -EFAULT;
		return -1;
	}

	memcpy(u->release, release, sz);
	return 0;
}