1/*
2 *
3 *   Copyright (c) International Business Machines  Corp., 2001
4 *
5 *   This program is free software;  you can redistribute it and/or modify
6 *   it under the terms of the GNU General Public License as published by
7 *   the Free Software Foundation; either version 2 of the License, or
8 *   (at your option) any later version.
9 *
10 *   This program is distributed in the hope that it will be useful,
11 *   but WITHOUT ANY WARRANTY;  without even the implied warranty of
12 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
13 *   the GNU General Public License for more details.
14 *
15 *   You should have received a copy of the GNU General Public License
16 *   along with this program;  if not, write to the Free Software
17 *   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
18 */
19
20/*
21 * NAME
22 *	modify_ldt02.c
23 *
24 * DESCRIPTION
25 *	Testcase to check the error conditions for modify_ldt(2)
26 *
27 * ALGORITHM
28 *	block1:
29 *		Create a segment at entry 0 and a valid base address.
30 *		Read the contents of the segment thru' fs register.
31 *		Validate the data.
32 *		Write an invalid base address into entry 0.
33 *		Read the contents of entry 0 in the child process.
34 *		Verify that a SIGSEGV is incurred.
35 *
36 * USAGE
37 *	modify_ldt02
38 *
39 * HISTORY
40 *	07/2001 Ported by Wayne Boyer
41 *
42 * RESTRICTIONS
43 *	None
44 */
45
46#include "config.h"
47#include "test.h"
48
49TCID_DEFINE(modify_ldt02);
50int TST_TOTAL = 1;
51
52#if defined(__i386__) && defined(HAVE_MODIFY_LDT)
53
54#ifdef HAVE_ASM_LDT_H
55#include <asm/ldt.h>
56#endif
57extern int modify_ldt(int, void *, unsigned long);
58
59#include <asm/unistd.h>
60#include <string.h>
61#include <sys/wait.h>
62#include <errno.h>
63
64/* Newer ldt.h files use user_desc, instead of modify_ldt_ldt_s */
65#ifdef HAVE_STRUCT_USER_DESC
66typedef struct user_desc modify_ldt_s;
67#elif  HAVE_STRUCT_MODIFY_LDT_LDT_S
68typedef struct modify_ldt_ldt_s modify_ldt_s;
69#else
70typedef struct modify_ldt_ldt_t {
71	unsigned int entry_number;
72	unsigned long int base_addr;
73	unsigned int limit;
74	unsigned int seg_32bit:1;
75	unsigned int contents:2;
76	unsigned int read_exec_only:1;
77	unsigned int limit_in_pages:1;
78	unsigned int seg_not_present:1;
79	unsigned int useable:1;
80	unsigned int empty:25;
81} modify_ldt_s;
82#endif
83
84int create_segment(void *, size_t);
85int read_segment(unsigned int);
86void cleanup(void);
87void setup(void);
88
89#define FAILED 1
90
91int main(int ac, char **av)
92{
93	int lc;
94
95	int val, pid, status;
96
97	int flag;
98	int seg[4];
99
100	tst_parse_opts(ac, av, NULL, NULL);
101
102	setup();		/* global setup */
103
104	/* The following loop checks looping state if -i option given */
105	for (lc = 0; TEST_LOOPING(lc); lc++) {
106
107		/* reset tst_count in case we are looping */
108		tst_count = 0;
109
110//block1:
111		tst_resm(TINFO, "Enter block 1");
112		flag = 0;
113
114		seg[0] = 12345;
115		if (create_segment(seg, sizeof(seg)) == -1) {
116			tst_brkm(TINFO, cleanup, "Creation of segment failed");
117		}
118
119		val = read_segment(0);
120
121		if (val != seg[0]) {
122			tst_resm(TFAIL, "Invalid value read %d, expected %d",
123				 val, seg[0]);
124			flag = FAILED;
125		}
126
127		if (flag) {
128			tst_resm(TINFO, "block 1 FAILED");
129		} else {
130			tst_resm(TINFO, "block 1 PASSED");
131		}
132
133		tst_resm(TINFO, "Exit block 1");
134
135//block2:
136		tst_resm(TINFO, "Enter block 2");
137		flag = 0;
138
139		if (create_segment(0, 10) == -1) {
140			tst_brkm(TINFO, cleanup, "Creation of segment failed");
141		}
142
143		tst_flush();
144		if ((pid = FORK_OR_VFORK()) == 0) {
145			val = read_segment(0);
146			exit(1);
147		}
148
149		(void)waitpid(pid, &status, 0);
150
151		if (WEXITSTATUS(status) != 0) {
152			flag = FAILED;
153			tst_resm(TFAIL, "Did not generate SEGV, child returned "
154				 "unexpected status");
155		}
156
157		if (flag) {
158			tst_resm(TINFO, "block 2 FAILED");
159		} else {
160			tst_resm(TINFO, "block 2 PASSED");
161		}
162	}
163	cleanup();
164	tst_exit();
165
166}
167
168int create_segment(void *seg, size_t size)
169{
170	modify_ldt_s entry;
171
172	entry.entry_number = 0;
173	entry.base_addr = (unsigned long)seg;
174	entry.limit = size;
175	entry.seg_32bit = 1;
176	entry.contents = 0;
177	entry.read_exec_only = 0;
178	entry.limit_in_pages = 0;
179	entry.seg_not_present = 0;
180
181	return modify_ldt(1, &entry, sizeof(entry));
182}
183
184int read_segment(unsigned int index)
185{
186	int res;
187	__asm__ __volatile__("\n\
188			push    $0x0007;\n\
189			pop     %%fs;\n\
190			movl    %%fs:(%1), %0":"=r"(res)
191			     :"r"(index * sizeof(int)));
192	return res;
193}
194
195void sigsegv_handler(int sig)
196{
197	tst_resm(TINFO, "received signal: %d", sig);
198	exit(0);
199}
200
201/*
202 * setup() - performs all ONE TIME setup for this test
203 */
204void setup(void)
205{
206	struct sigaction act;
207
208	memset(&act, 0, sizeof(act));
209	sigemptyset(&act.sa_mask);
210
211	tst_sig(FORK, DEF_HANDLER, cleanup);
212
213	act.sa_handler = sigsegv_handler;
214	(void)sigaction(SIGSEGV, &act, NULL);
215
216	TEST_PAUSE;
217}
218
219/*
220 * cleanup() - performs all the ONE TIME cleanup for this test at completion
221 * or premature exit.
222 */
223void cleanup(void)
224{
225
226}
227#elif HAVE_MODIFY_LDT
228int main(void)
229{
230	tst_brkm(TCONF,
231		 NULL,
232		 "modify_ldt is available but not tested on the platform than __i386__");
233}
234
235#else /* if defined(__i386__) */
236
237int main(void)
238{
239	tst_resm(TINFO, "modify_ldt02 test only for ix86");
240	tst_exit();
241}
242
243#endif /* if defined(__i386__) */
244