1 /* Testing s390x PTRACE_SINGLEBLOCK ptrace request.
2 Copyright (C) 2017-2023 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 The GNU C Library 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 the GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <https://www.gnu.org/licenses/>. */
18
19 #include <stdio.h>
20 #include <stdlib.h>
21 #include <string.h>
22 #include <unistd.h>
23 #include <sys/wait.h>
24 #include <sys/types.h>
25 #include <sys/uio.h>
26 #include <elf.h>
27 #include <support/xstdlib.h>
28 #include <support/xunistd.h>
29 #include <support/check.h>
30 #include <string.h>
31 #include <errno.h>
32
33 /* Ensure that we use the PTRACE_SINGLEBLOCK definition from glibc ptrace.h
34 in tracer_func. We need the kernel ptrace.h for structs ptrace_area
35 and gregset_t. */
36 #include <sys/ptrace.h>
37 static const enum __ptrace_request req_singleblock = PTRACE_SINGLEBLOCK;
38 #include <asm/ptrace.h>
39
40 static void
41 tracee_func (int pid)
42 {
43 /* Dump the mapping information for manual inspection of the printed
44 tracee addresses. */
45 char str[80];
46 sprintf (str, "cat /proc/%d/maps", pid);
47 puts (str);
48 xsystem (str);
49 fflush (stdout);
50
51 TEST_VERIFY_EXIT (ptrace (PTRACE_TRACEME) == 0);
52 /* Stop tracee. Afterwards the tracer_func can operate. */
53 kill (pid, SIGSTOP);
54
55 puts ("The PTRACE_SINGLEBLOCK of the tracer will stop after: "
56 "brasl %r14,<puts@plt>!");
57 }
58
59 static void
60 tracer_func (int pid)
61 {
62 unsigned long last_break;
63 ptrace_area parea;
64 gregset_t regs;
65 struct iovec parea2;
66 gregset_t regs2;
67
68 int status;
69 int ret;
70 #define MAX_CHARS_IN_BUF 4096
71 char buf[MAX_CHARS_IN_BUF + 1];
72 size_t buf_count;
73
74 while (1)
75 {
76 /* Wait for the tracee to be stopped or exited. */
77 wait (&status);
78 if (WIFEXITED (status))
79 break;
80
81 /* Get information about tracee: gprs, last breaking address. */
82 parea.len = sizeof (regs);
83 parea.process_addr = (unsigned long) ®s;
84 parea.kernel_addr = 0;
85 TEST_VERIFY_EXIT (ptrace (PTRACE_PEEKUSR_AREA, pid, &parea) == 0);
86 TEST_VERIFY_EXIT (ptrace (PTRACE_GET_LAST_BREAK, pid, NULL, &last_break)
87 == 0);
88
89 parea2.iov_len = sizeof (regs2);
90 parea2.iov_base = ®s2;
91 TEST_VERIFY_EXIT (ptrace (PTRACE_GETREGSET, pid, NT_PRSTATUS, &parea2)
92 == 0);
93 TEST_VERIFY_EXIT (parea2.iov_len == sizeof (regs2));
94
95 /* Test if gprs obtained by PTRACE_PEEKUSR_AREA and PTRACE_GETREGESET
96 have the same values. */
97 TEST_VERIFY_EXIT (memcmp (®s, ®s2, sizeof (regs)) == 0);
98
99 printf ("child IA: %p last_break: %p\n",
100 (void *) regs[1], (void *) last_break);
101
102 /* Execute tracee until next taken branch.
103
104 Note:
105 Before the commit which introduced this testcase,
106 <glibc>/sysdeps/unix/sysv/linux/s390/sys/ptrace.h
107 uses ptrace-request 12 for PTRACE_GETREGS,
108 but <kernel>/include/uapi/linux/ptrace.h
109 uses 12 for PTRACE_SINGLEBLOCK.
110
111 The s390 kernel has no support for PTRACE_GETREGS!
112 Thus glibc ptrace.h is adjusted to match kernel ptrace.h.
113
114 The glibc sys/ptrace.h header contains the identifier
115 PTRACE_SINGLEBLOCK in enum __ptrace_request. In contrast, the kernel
116 asm/ptrace.h header defines PTRACE_SINGLEBLOCK.
117
118 This test ensures, that PTRACE_SINGLEBLOCK defined in glibc
119 works as expected. If the kernel would interpret it as
120 PTRACE_GETREGS, then the tracee will not make any progress
121 and this testcase will time out or the ptrace call will fail with
122 different errors. */
123
124 /* Ptrace request 12 is first done with data argument pointing to
125 a buffer:
126 -If request 12 is interpreted as PTRACE_GETREGS, it will store the regs
127 to buffer without an error.
128
129 -If request 12 is interpreted as PTRACE_SINGLEBLOCK, it will fail
130 as data argument is used as signal-number and the address of
131 buf is no valid signal.
132
133 -If request 12 is not implemented, it will also fail.
134
135 Here the test expects that the buffer is untouched and an error is
136 returned. */
137 memset (buf, 'a', MAX_CHARS_IN_BUF);
138 ret = ptrace (req_singleblock, pid, NULL, buf);
139 buf [MAX_CHARS_IN_BUF] = '\0';
140 buf_count = strspn (buf, "a");
141 TEST_VERIFY_EXIT (buf_count == MAX_CHARS_IN_BUF);
142 TEST_VERIFY_EXIT (ret == -1);
143
144 /* If request 12 is interpreted as PTRACE_GETREGS, the first ptrace
145 call will touch the buffer which is detected by this test. */
146 errno = 0;
147 ret = ptrace (req_singleblock, pid, NULL, NULL);
148 if (ret == 0)
149 {
150 /* The kernel has support for PTRACE_SINGLEBLOCK ptrace request. */
151 TEST_VERIFY_EXIT (errno == 0);
152 }
153 else
154 {
155 /* The kernel (< 3.15) has no support for PTRACE_SINGLEBLOCK ptrace
156 request. */
157 TEST_VERIFY_EXIT (errno == EIO);
158 TEST_VERIFY_EXIT (ret == -1);
159
160 /* Just continue tracee until it exits normally. */
161 TEST_VERIFY_EXIT (ptrace (PTRACE_CONT, pid, NULL, NULL) == 0);
162 }
163 }
164 }
165
166 static int
167 do_test (void)
168 {
169 int pid;
170 pid = xfork ();
171 if (pid)
172 tracer_func (pid);
173 else
174 tracee_func (getpid ());
175
176 return EXIT_SUCCESS;
177 }
178
179 #include <support/test-driver.c>