1 | /* |
2 | * Copyright (c) 2015 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 | #include <kern/kalloc.h> |
29 | #include <kern/locks.h> |
30 | #include <sys/kernel.h> |
31 | #include <sys/kernel_types.h> |
32 | #include <kern/zalloc.h> |
33 | #include <sys/reason.h> |
34 | #include <string.h> |
35 | #include <kern/assert.h> |
36 | #include <kern/debug.h> |
37 | |
38 | #if OS_REASON_DEBUG |
39 | #include <pexpert/pexpert.h> |
40 | |
41 | extern int os_reason_debug_disabled; |
42 | #endif |
43 | |
44 | extern int maxproc; |
45 | |
46 | /* |
47 | * Lock group attributes for os_reason subsystem |
48 | */ |
49 | lck_grp_attr_t *os_reason_lock_grp_attr; |
50 | lck_grp_t *os_reason_lock_grp; |
51 | lck_attr_t *os_reason_lock_attr; |
52 | |
53 | #define OS_REASON_RESERVE_COUNT 100 |
54 | #define OS_REASON_MAX_COUNT (maxproc + 100) |
55 | |
56 | static struct zone *os_reason_zone; |
57 | static int os_reason_alloc_buffer_internal(os_reason_t cur_reason, uint32_t osr_bufsize, |
58 | boolean_t can_block); |
59 | |
60 | void |
61 | os_reason_init() |
62 | { |
63 | int reasons_allocated = 0; |
64 | |
65 | /* |
66 | * Initialize OS reason group and lock attributes |
67 | */ |
68 | os_reason_lock_grp_attr = lck_grp_attr_alloc_init(); |
69 | os_reason_lock_grp = lck_grp_alloc_init("os_reason_lock" , os_reason_lock_grp_attr); |
70 | os_reason_lock_attr = lck_attr_alloc_init(); |
71 | |
72 | /* |
73 | * Create OS reason zone. |
74 | */ |
75 | os_reason_zone = zinit(sizeof(struct os_reason), OS_REASON_MAX_COUNT * sizeof(struct os_reason), |
76 | OS_REASON_MAX_COUNT, "os reasons" ); |
77 | if (os_reason_zone == NULL) { |
78 | panic("failed to initialize os_reason_zone" ); |
79 | } |
80 | |
81 | /* |
82 | * We pre-fill the OS reason zone to reduce the likelihood that |
83 | * the jetsam thread and others block when they create an exit |
84 | * reason. This pre-filled memory is not-collectable since it's |
85 | * foreign memory crammed in as part of zfill(). |
86 | */ |
87 | reasons_allocated = zfill(os_reason_zone, OS_REASON_RESERVE_COUNT); |
88 | assert(reasons_allocated > 0); |
89 | } |
90 | |
91 | /* |
92 | * Creates a new reason and initializes it with the provided reason |
93 | * namespace and code. Also sets up the buffer and kcdata_descriptor |
94 | * associated with the reason. Returns a pointer to the newly created |
95 | * reason. |
96 | * |
97 | * Returns: |
98 | * REASON_NULL if unable to allocate a reason or initialize the nested buffer |
99 | * a pointer to the reason otherwise |
100 | */ |
101 | os_reason_t |
102 | os_reason_create(uint32_t osr_namespace, uint64_t osr_code) |
103 | { |
104 | os_reason_t new_reason = OS_REASON_NULL; |
105 | |
106 | new_reason = (os_reason_t) zalloc(os_reason_zone); |
107 | if (new_reason == OS_REASON_NULL) { |
108 | #if OS_REASON_DEBUG |
109 | /* |
110 | * We rely on OS reasons to communicate important things such |
111 | * as process exit reason information, we should be aware |
112 | * when issues prevent us from allocating them. |
113 | */ |
114 | if (os_reason_debug_disabled) { |
115 | kprintf("os_reason_create: failed to allocate reason with namespace: %u, code : %llu\n" , |
116 | osr_namespace, osr_code); |
117 | } else { |
118 | panic("os_reason_create: failed to allocate reason with namespace: %u, code: %llu\n" , |
119 | osr_namespace, osr_code); |
120 | } |
121 | #endif |
122 | return new_reason; |
123 | } |
124 | |
125 | bzero(new_reason, sizeof(*new_reason)); |
126 | |
127 | new_reason->osr_namespace = osr_namespace; |
128 | new_reason->osr_code = osr_code; |
129 | new_reason->osr_flags = 0; |
130 | new_reason->osr_bufsize = 0; |
131 | new_reason->osr_kcd_buf = NULL; |
132 | |
133 | lck_mtx_init(&new_reason->osr_lock, os_reason_lock_grp, os_reason_lock_attr); |
134 | new_reason->osr_refcount = 1; |
135 | |
136 | return new_reason; |
137 | } |
138 | |
139 | static void |
140 | os_reason_dealloc_buffer(os_reason_t cur_reason) |
141 | { |
142 | assert(cur_reason != OS_REASON_NULL); |
143 | LCK_MTX_ASSERT(&cur_reason->osr_lock, LCK_MTX_ASSERT_OWNED); |
144 | |
145 | if (cur_reason->osr_kcd_buf != NULL && cur_reason->osr_bufsize != 0) { |
146 | kfree(cur_reason->osr_kcd_buf, cur_reason->osr_bufsize); |
147 | } |
148 | |
149 | cur_reason->osr_bufsize = 0; |
150 | cur_reason->osr_kcd_buf = NULL; |
151 | bzero(&cur_reason->osr_kcd_descriptor, sizeof(cur_reason->osr_kcd_descriptor)); |
152 | |
153 | return; |
154 | } |
155 | |
156 | /* |
157 | * Allocates and initializes a buffer of specified size for the reason. This function |
158 | * may block and should not be called from extremely performance sensitive contexts |
159 | * (i.e. jetsam). Also initializes the kcdata descriptor accordingly. If there is an |
160 | * existing buffer, we dealloc the buffer before allocating a new one and |
161 | * clear the associated kcdata descriptor. If osr_bufsize is passed as 0, |
162 | * we deallocate the existing buffer and then return. |
163 | * |
164 | * Returns: |
165 | * 0 on success |
166 | * EINVAL if the passed reason pointer is invalid or the requested size is |
167 | * larger than REASON_BUFFER_MAX_SIZE |
168 | * EIO if we fail to initialize the kcdata buffer |
169 | */ |
170 | int |
171 | os_reason_alloc_buffer(os_reason_t cur_reason, uint32_t osr_bufsize) |
172 | { |
173 | return os_reason_alloc_buffer_internal(cur_reason, osr_bufsize, TRUE); |
174 | } |
175 | |
176 | /* |
177 | * Allocates and initializes a buffer of specified size for the reason. Also |
178 | * initializes the kcdata descriptor accordingly. If there is an existing |
179 | * buffer, we dealloc the buffer before allocating a new one and |
180 | * clear the associated kcdata descriptor. If osr_bufsize is passed as 0, |
181 | * we deallocate the existing buffer and then return. |
182 | * |
183 | * Returns: |
184 | * 0 on success |
185 | * EINVAL if the passed reason pointer is invalid or the requested size is |
186 | * larger than REASON_BUFFER_MAX_SIZE |
187 | * ENOMEM if unable to allocate memory for the buffer |
188 | * EIO if we fail to initialize the kcdata buffer |
189 | */ |
190 | int |
191 | os_reason_alloc_buffer_noblock(os_reason_t cur_reason, uint32_t osr_bufsize) |
192 | { |
193 | return os_reason_alloc_buffer_internal(cur_reason, osr_bufsize, FALSE); |
194 | } |
195 | |
196 | static int |
197 | os_reason_alloc_buffer_internal(os_reason_t cur_reason, uint32_t osr_bufsize, |
198 | boolean_t can_block) |
199 | { |
200 | if (cur_reason == OS_REASON_NULL) { |
201 | return EINVAL; |
202 | } |
203 | |
204 | if (osr_bufsize > OS_REASON_BUFFER_MAX_SIZE) { |
205 | return EINVAL; |
206 | } |
207 | |
208 | lck_mtx_lock(&cur_reason->osr_lock); |
209 | |
210 | os_reason_dealloc_buffer(cur_reason); |
211 | |
212 | if (osr_bufsize == 0) { |
213 | lck_mtx_unlock(&cur_reason->osr_lock); |
214 | return 0; |
215 | } |
216 | |
217 | if (can_block) { |
218 | cur_reason->osr_kcd_buf = kalloc_tag(osr_bufsize, VM_KERN_MEMORY_REASON); |
219 | assert(cur_reason->osr_kcd_buf != NULL); |
220 | } else { |
221 | cur_reason->osr_kcd_buf = kalloc_noblock_tag(osr_bufsize, VM_KERN_MEMORY_REASON); |
222 | if (cur_reason->osr_kcd_buf == NULL) { |
223 | lck_mtx_unlock(&cur_reason->osr_lock); |
224 | return ENOMEM; |
225 | } |
226 | } |
227 | |
228 | bzero(cur_reason->osr_kcd_buf, osr_bufsize); |
229 | |
230 | cur_reason->osr_bufsize = osr_bufsize; |
231 | |
232 | if (kcdata_memory_static_init(&cur_reason->osr_kcd_descriptor, (mach_vm_address_t) cur_reason->osr_kcd_buf, |
233 | KCDATA_BUFFER_BEGIN_OS_REASON, osr_bufsize, KCFLAG_USE_MEMCOPY) != KERN_SUCCESS) { |
234 | os_reason_dealloc_buffer(cur_reason); |
235 | |
236 | lck_mtx_unlock(&cur_reason->osr_lock); |
237 | return EIO; |
238 | } |
239 | |
240 | lck_mtx_unlock(&cur_reason->osr_lock); |
241 | |
242 | return 0; |
243 | } |
244 | |
245 | /* |
246 | * Returns a pointer to the kcdata descriptor associated with the specified |
247 | * reason if there is a buffer allocated. |
248 | */ |
249 | struct kcdata_descriptor * |
250 | os_reason_get_kcdata_descriptor(os_reason_t cur_reason) |
251 | { |
252 | if (cur_reason == OS_REASON_NULL) { |
253 | return NULL; |
254 | } |
255 | |
256 | if (cur_reason->osr_kcd_buf == NULL) { |
257 | return NULL; |
258 | } |
259 | |
260 | assert(cur_reason->osr_kcd_descriptor.kcd_addr_begin == (mach_vm_address_t) cur_reason->osr_kcd_buf); |
261 | if (cur_reason->osr_kcd_descriptor.kcd_addr_begin != (mach_vm_address_t) cur_reason->osr_kcd_buf) { |
262 | return NULL; |
263 | } |
264 | |
265 | return &cur_reason->osr_kcd_descriptor; |
266 | } |
267 | |
268 | /* |
269 | * Takes a reference on the passed reason. |
270 | */ |
271 | void |
272 | os_reason_ref(os_reason_t cur_reason) |
273 | { |
274 | if (cur_reason == OS_REASON_NULL) { |
275 | return; |
276 | } |
277 | |
278 | lck_mtx_lock(&cur_reason->osr_lock); |
279 | |
280 | assert(cur_reason->osr_refcount > 0); |
281 | if (os_add_overflow(cur_reason->osr_refcount, 1, &cur_reason->osr_refcount)) { |
282 | panic("os reason refcount overflow" ); |
283 | } |
284 | |
285 | lck_mtx_unlock(&cur_reason->osr_lock); |
286 | |
287 | return; |
288 | } |
289 | |
290 | /* |
291 | * Drops a reference on the passed reason, deallocates |
292 | * the reason if no references remain. |
293 | */ |
294 | void |
295 | os_reason_free(os_reason_t cur_reason) |
296 | { |
297 | if (cur_reason == OS_REASON_NULL) { |
298 | return; |
299 | } |
300 | |
301 | lck_mtx_lock(&cur_reason->osr_lock); |
302 | |
303 | if (cur_reason->osr_refcount == 0) { |
304 | panic("os_reason_free called on reason with zero refcount" ); |
305 | } |
306 | |
307 | cur_reason->osr_refcount--; |
308 | if (cur_reason->osr_refcount != 0) { |
309 | lck_mtx_unlock(&cur_reason->osr_lock); |
310 | return; |
311 | } |
312 | |
313 | os_reason_dealloc_buffer(cur_reason); |
314 | |
315 | lck_mtx_unlock(&cur_reason->osr_lock); |
316 | lck_mtx_destroy(&cur_reason->osr_lock, os_reason_lock_grp); |
317 | |
318 | zfree(os_reason_zone, cur_reason); |
319 | } |
320 | |