1 | /* |
2 | * Copyright (c) 2016-2020 Apple Inc. All rights reserved. |
3 | * |
4 | * @APPLE_OSREFERENCE_LICENSE_HEADER_START@ |
5 | * |
6 | * This file contains Original Code and/or Modifications of Original Code |
7 | * as defined in and that are subject to the Apple Public Source License |
8 | * Version 2.0 (the 'License'). You may not use this file except in |
9 | * compliance with the License. The rights granted to you under the License |
10 | * may not be used to create, or enable the creation or redistribution of, |
11 | * unlawful or unlicensed copies of an Apple operating system, or to |
12 | * circumvent, violate, or enable the circumvention or violation of, any |
13 | * terms of an Apple operating system software license agreement. |
14 | * |
15 | * Please obtain a copy of the License at |
16 | * http://www.opensource.apple.com/apsl/ and read it before using this file. |
17 | * |
18 | * The Original Code and all software distributed under the License are |
19 | * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER |
20 | * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, |
21 | * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, |
22 | * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. |
23 | * Please see the License for the specific language governing rights and |
24 | * limitations under the License. |
25 | * |
26 | * @APPLE_OSREFERENCE_LICENSE_HEADER_END@ |
27 | */ |
28 | |
29 | #include <kern/backtrace.h> |
30 | #include <kern/kalloc.h> |
31 | #include <sys/errno.h> |
32 | #include <sys/sysctl.h> |
33 | #include <sys/systm.h> |
34 | |
35 | #if DEVELOPMENT || DEBUG |
36 | |
37 | /* |
38 | * Ignore -Wxnu-typed-allocators for this file, as it implements |
39 | * sysctls that are only available for DEVELOPMENT || DEBUG builds. |
40 | */ |
41 | __typed_allocators_ignore_push |
42 | |
43 | #define MAX_BACKTRACE (128) |
44 | |
45 | #define BACKTRACE_USER (0) |
46 | #define BACKTRACE_USER_RESUME (1) |
47 | static int backtrace_user_sysctl SYSCTL_HANDLER_ARGS; |
48 | |
49 | #define BACKTRACE_KERN_TEST_PACK_UNPACK (0) |
50 | #define BACKTRACE_KERN_TEST_PACKED (1) |
51 | static int backtrace_kernel_sysctl SYSCTL_HANDLER_ARGS; |
52 | |
53 | SYSCTL_NODE(_kern, OID_AUTO, backtrace, CTLFLAG_RW | CTLFLAG_LOCKED, 0, |
54 | "backtrace" ); |
55 | |
56 | SYSCTL_PROC(_kern_backtrace, OID_AUTO, user, |
57 | CTLFLAG_RW | CTLFLAG_LOCKED, (void *)BACKTRACE_USER, |
58 | sizeof(uint64_t), backtrace_user_sysctl, "O" , |
59 | "take user backtrace of current thread" ); |
60 | |
61 | SYSCTL_PROC(_kern_backtrace, OID_AUTO, kernel_tests, |
62 | CTLFLAG_RW | CTLFLAG_LOCKED, (void *)BACKTRACE_USER, |
63 | sizeof(uint64_t), backtrace_kernel_sysctl, "O" , |
64 | "take user backtrace of current thread" ); |
65 | |
66 | static int |
67 | backtrace_kernel_sysctl SYSCTL_HANDLER_ARGS |
68 | { |
69 | unsigned int scenario = (unsigned int)req->newlen; |
70 | uintptr_t *bt = NULL; |
71 | uint8_t *packed_bt = NULL; |
72 | uintptr_t *unpacked_bt = NULL; |
73 | unsigned int bt_len = 0; |
74 | size_t bt_size = 0; |
75 | errno_t error = 0; |
76 | |
77 | bt_len = 24; |
78 | bt_size = sizeof(bt[0]) * bt_len; |
79 | bt = kalloc_data(bt_size, Z_WAITOK | Z_ZERO); |
80 | packed_bt = kalloc_data(bt_size, Z_WAITOK | Z_ZERO); |
81 | unpacked_bt = kalloc_data(bt_size, Z_WAITOK | Z_ZERO); |
82 | if (!bt || !packed_bt || !unpacked_bt) { |
83 | error = ENOBUFS; |
84 | goto out; |
85 | } |
86 | backtrace_info_t info = BTI_NONE; |
87 | unsigned int len = backtrace(bt, bt_len, NULL, &info); |
88 | backtrace_info_t packed_info = BTI_NONE; |
89 | size_t packed_size = 0; |
90 | if (scenario == BACKTRACE_KERN_TEST_PACK_UNPACK) { |
91 | packed_size = backtrace_pack(BTP_KERN_OFFSET_32, packed_bt, bt_size, |
92 | bt, len); |
93 | } else { |
94 | packed_size = backtrace_packed(BTP_KERN_OFFSET_32, packed_bt, bt_size, |
95 | NULL, &packed_info); |
96 | } |
97 | unsigned int unpacked_len = backtrace_unpack(BTP_KERN_OFFSET_32, |
98 | unpacked_bt, bt_len, packed_bt, packed_size); |
99 | if (unpacked_len != len) { |
100 | printf("backtrace_tests: length %u != %u unpacked\n" , len, |
101 | unpacked_len); |
102 | error = ERANGE; |
103 | goto out; |
104 | } |
105 | for (unsigned int i = 0; i < len; i++) { |
106 | if (unpacked_bt[i] != bt[i]) { |
107 | printf("backtrace_tests: bad address %u: 0x%lx != 0x%lx unpacked" , |
108 | i, bt[i], unpacked_bt[i]); |
109 | error = EINVAL; |
110 | } |
111 | } |
112 | |
113 | out: |
114 | if (bt) { |
115 | kfree_data(bt, bt_size); |
116 | } |
117 | if (packed_bt) { |
118 | kfree_data(packed_bt, bt_size); |
119 | } |
120 | if (unpacked_bt) { |
121 | kfree_data(unpacked_bt, bt_size); |
122 | } |
123 | return error; |
124 | } |
125 | |
126 | static int |
127 | backtrace_user_sysctl SYSCTL_HANDLER_ARGS |
128 | { |
129 | #pragma unused(oidp, arg1, arg2) |
130 | unsigned int scenario = (unsigned int)req->newlen; |
131 | uintptr_t *bt = NULL; |
132 | unsigned int bt_len = 0, bt_filled = 0, bt_space = 0; |
133 | size_t bt_size = 0; |
134 | errno_t error = 0; |
135 | |
136 | bool user_scenario = scenario == BACKTRACE_USER; |
137 | bool resume_scenario = scenario == BACKTRACE_USER_RESUME; |
138 | if (!user_scenario && !resume_scenario) { |
139 | return ENOTSUP; |
140 | } |
141 | |
142 | if (req->oldptr == USER_ADDR_NULL || req->oldlen == 0) { |
143 | return EFAULT; |
144 | } |
145 | |
146 | bt_len = req->oldlen > MAX_BACKTRACE ? MAX_BACKTRACE : |
147 | (unsigned int)req->oldlen; |
148 | bt_size = sizeof(bt[0]) * bt_len; |
149 | bt = kalloc_data(bt_size, Z_WAITOK | Z_ZERO); |
150 | if (!bt) { |
151 | return ENOBUFS; |
152 | } |
153 | bt_space = resume_scenario ? bt_len / 2 : bt_len; |
154 | struct backtrace_user_info btinfo = BTUINFO_INIT; |
155 | bt_filled = backtrace_user(bt, bt_space, NULL, &btinfo); |
156 | error = btinfo.btui_error; |
157 | if (error != 0) { |
158 | goto out; |
159 | } |
160 | if (resume_scenario) { |
161 | if (!(btinfo.btui_info & BTI_TRUNCATED)) { |
162 | error = ENOSPC; |
163 | goto out; |
164 | } |
165 | struct backtrace_control ctl = { |
166 | .btc_frame_addr = btinfo.btui_next_frame_addr, |
167 | }; |
168 | btinfo = BTUINFO_INIT; |
169 | unsigned int bt_more = backtrace_user(bt + bt_filled, bt_space, &ctl, |
170 | &btinfo); |
171 | error = btinfo.btui_error; |
172 | if (error != 0) { |
173 | goto out; |
174 | } |
175 | bt_filled += bt_more; |
176 | } |
177 | bt_filled = min(bt_filled, bt_len); |
178 | if (btinfo.btui_async_frame_addr != 0 && |
179 | btinfo.btui_async_start_index != 0) { |
180 | // Put the async call stack inline after the real call stack. |
181 | unsigned int start_index = btinfo.btui_async_start_index; |
182 | uintptr_t frame_addr = btinfo.btui_async_frame_addr; |
183 | unsigned int bt_left = bt_len - start_index; |
184 | struct backtrace_control ctl = { .btc_frame_addr = frame_addr, }; |
185 | btinfo = BTUINFO_INIT; |
186 | unsigned int async_filled = backtrace_user(bt + start_index, bt_left, |
187 | &ctl, &btinfo); |
188 | error = btinfo.btui_error; |
189 | if (error != 0) { |
190 | goto out; |
191 | } |
192 | bt_filled = min(start_index + async_filled, bt_len); |
193 | } |
194 | |
195 | error = copyout(bt, req->oldptr, sizeof(bt[0]) * bt_filled); |
196 | if (error) { |
197 | goto out; |
198 | } |
199 | req->oldidx = bt_filled; |
200 | |
201 | out: |
202 | kfree_data(bt, bt_size); |
203 | return error; |
204 | } |
205 | |
206 | __typed_allocators_ignore_pop |
207 | |
208 | #endif /* DEVELOPMENT || DEBUG */ |
209 | |