Commit | Line | Data |
---|---|---|
16d69265 | 1 | #include <linux/mm.h> |
30992c97 MM |
2 | #include <linux/slab.h> |
3 | #include <linux/string.h> | |
3b32123d | 4 | #include <linux/compiler.h> |
b95f1b31 | 5 | #include <linux/export.h> |
96840aa0 | 6 | #include <linux/err.h> |
3b8f14b4 | 7 | #include <linux/sched.h> |
eb36c587 | 8 | #include <linux/security.h> |
9800339b | 9 | #include <linux/swap.h> |
33806f06 | 10 | #include <linux/swapops.h> |
00619bcc JM |
11 | #include <linux/mman.h> |
12 | #include <linux/hugetlb.h> | |
39f1f78d | 13 | #include <linux/vmalloc.h> |
00619bcc | 14 | |
96840aa0 | 15 | #include <asm/uaccess.h> |
30992c97 | 16 | |
6038def0 NK |
17 | #include "internal.h" |
18 | ||
30992c97 | 19 | /** |
30992c97 | 20 | * kstrdup - allocate space for and copy an existing string |
30992c97 MM |
21 | * @s: the string to duplicate |
22 | * @gfp: the GFP mask used in the kmalloc() call when allocating memory | |
23 | */ | |
24 | char *kstrdup(const char *s, gfp_t gfp) | |
25 | { | |
26 | size_t len; | |
27 | char *buf; | |
28 | ||
29 | if (!s) | |
30 | return NULL; | |
31 | ||
32 | len = strlen(s) + 1; | |
1d2c8eea | 33 | buf = kmalloc_track_caller(len, gfp); |
30992c97 MM |
34 | if (buf) |
35 | memcpy(buf, s, len); | |
36 | return buf; | |
37 | } | |
38 | EXPORT_SYMBOL(kstrdup); | |
96840aa0 | 39 | |
1e66df3e JF |
40 | /** |
41 | * kstrndup - allocate space for and copy an existing string | |
42 | * @s: the string to duplicate | |
43 | * @max: read at most @max chars from @s | |
44 | * @gfp: the GFP mask used in the kmalloc() call when allocating memory | |
45 | */ | |
46 | char *kstrndup(const char *s, size_t max, gfp_t gfp) | |
47 | { | |
48 | size_t len; | |
49 | char *buf; | |
50 | ||
51 | if (!s) | |
52 | return NULL; | |
53 | ||
54 | len = strnlen(s, max); | |
55 | buf = kmalloc_track_caller(len+1, gfp); | |
56 | if (buf) { | |
57 | memcpy(buf, s, len); | |
58 | buf[len] = '\0'; | |
59 | } | |
60 | return buf; | |
61 | } | |
62 | EXPORT_SYMBOL(kstrndup); | |
63 | ||
1a2f67b4 AD |
64 | /** |
65 | * kmemdup - duplicate region of memory | |
66 | * | |
67 | * @src: memory region to duplicate | |
68 | * @len: memory region length | |
69 | * @gfp: GFP mask to use | |
70 | */ | |
71 | void *kmemdup(const void *src, size_t len, gfp_t gfp) | |
72 | { | |
73 | void *p; | |
74 | ||
1d2c8eea | 75 | p = kmalloc_track_caller(len, gfp); |
1a2f67b4 AD |
76 | if (p) |
77 | memcpy(p, src, len); | |
78 | return p; | |
79 | } | |
80 | EXPORT_SYMBOL(kmemdup); | |
81 | ||
610a77e0 LZ |
82 | /** |
83 | * memdup_user - duplicate memory region from user space | |
84 | * | |
85 | * @src: source address in user space | |
86 | * @len: number of bytes to copy | |
87 | * | |
88 | * Returns an ERR_PTR() on failure. | |
89 | */ | |
90 | void *memdup_user(const void __user *src, size_t len) | |
91 | { | |
92 | void *p; | |
93 | ||
94 | /* | |
95 | * Always use GFP_KERNEL, since copy_from_user() can sleep and | |
96 | * cause pagefault, which makes it pointless to use GFP_NOFS | |
97 | * or GFP_ATOMIC. | |
98 | */ | |
99 | p = kmalloc_track_caller(len, GFP_KERNEL); | |
100 | if (!p) | |
101 | return ERR_PTR(-ENOMEM); | |
102 | ||
103 | if (copy_from_user(p, src, len)) { | |
104 | kfree(p); | |
105 | return ERR_PTR(-EFAULT); | |
106 | } | |
107 | ||
108 | return p; | |
109 | } | |
110 | EXPORT_SYMBOL(memdup_user); | |
111 | ||
96840aa0 DA |
112 | /* |
113 | * strndup_user - duplicate an existing string from user space | |
96840aa0 DA |
114 | * @s: The string to duplicate |
115 | * @n: Maximum number of bytes to copy, including the trailing NUL. | |
116 | */ | |
117 | char *strndup_user(const char __user *s, long n) | |
118 | { | |
119 | char *p; | |
120 | long length; | |
121 | ||
122 | length = strnlen_user(s, n); | |
123 | ||
124 | if (!length) | |
125 | return ERR_PTR(-EFAULT); | |
126 | ||
127 | if (length > n) | |
128 | return ERR_PTR(-EINVAL); | |
129 | ||
90d74045 | 130 | p = memdup_user(s, length); |
96840aa0 | 131 | |
90d74045 JL |
132 | if (IS_ERR(p)) |
133 | return p; | |
96840aa0 DA |
134 | |
135 | p[length - 1] = '\0'; | |
136 | ||
137 | return p; | |
138 | } | |
139 | EXPORT_SYMBOL(strndup_user); | |
16d69265 | 140 | |
6038def0 NK |
141 | void __vma_link_list(struct mm_struct *mm, struct vm_area_struct *vma, |
142 | struct vm_area_struct *prev, struct rb_node *rb_parent) | |
143 | { | |
144 | struct vm_area_struct *next; | |
145 | ||
146 | vma->vm_prev = prev; | |
147 | if (prev) { | |
148 | next = prev->vm_next; | |
149 | prev->vm_next = vma; | |
150 | } else { | |
151 | mm->mmap = vma; | |
152 | if (rb_parent) | |
153 | next = rb_entry(rb_parent, | |
154 | struct vm_area_struct, vm_rb); | |
155 | else | |
156 | next = NULL; | |
157 | } | |
158 | vma->vm_next = next; | |
159 | if (next) | |
160 | next->vm_prev = vma; | |
161 | } | |
162 | ||
b7643757 SP |
163 | /* Check if the vma is being used as a stack by this task */ |
164 | static int vm_is_stack_for_task(struct task_struct *t, | |
165 | struct vm_area_struct *vma) | |
166 | { | |
167 | return (vma->vm_start <= KSTK_ESP(t) && vma->vm_end >= KSTK_ESP(t)); | |
168 | } | |
169 | ||
170 | /* | |
171 | * Check if the vma is being used as a stack. | |
172 | * If is_group is non-zero, check in the entire thread group or else | |
173 | * just check in the current task. Returns the pid of the task that | |
174 | * the vma is stack for. | |
175 | */ | |
176 | pid_t vm_is_stack(struct task_struct *task, | |
177 | struct vm_area_struct *vma, int in_group) | |
178 | { | |
179 | pid_t ret = 0; | |
180 | ||
181 | if (vm_is_stack_for_task(task, vma)) | |
182 | return task->pid; | |
183 | ||
184 | if (in_group) { | |
185 | struct task_struct *t; | |
186 | rcu_read_lock(); | |
187 | if (!pid_alive(task)) | |
188 | goto done; | |
189 | ||
190 | t = task; | |
191 | do { | |
192 | if (vm_is_stack_for_task(t, vma)) { | |
193 | ret = t->pid; | |
194 | goto done; | |
195 | } | |
196 | } while_each_thread(task, t); | |
197 | done: | |
198 | rcu_read_unlock(); | |
199 | } | |
200 | ||
201 | return ret; | |
202 | } | |
203 | ||
efc1a3b1 | 204 | #if defined(CONFIG_MMU) && !defined(HAVE_ARCH_PICK_MMAP_LAYOUT) |
16d69265 AM |
205 | void arch_pick_mmap_layout(struct mm_struct *mm) |
206 | { | |
207 | mm->mmap_base = TASK_UNMAPPED_BASE; | |
208 | mm->get_unmapped_area = arch_get_unmapped_area; | |
16d69265 AM |
209 | } |
210 | #endif | |
912985dc | 211 | |
45888a0c XG |
212 | /* |
213 | * Like get_user_pages_fast() except its IRQ-safe in that it won't fall | |
214 | * back to the regular GUP. | |
25985edc | 215 | * If the architecture not support this function, simply return with no |
45888a0c XG |
216 | * page pinned |
217 | */ | |
3b32123d | 218 | int __weak __get_user_pages_fast(unsigned long start, |
45888a0c XG |
219 | int nr_pages, int write, struct page **pages) |
220 | { | |
221 | return 0; | |
222 | } | |
223 | EXPORT_SYMBOL_GPL(__get_user_pages_fast); | |
224 | ||
9de100d0 AG |
225 | /** |
226 | * get_user_pages_fast() - pin user pages in memory | |
227 | * @start: starting user address | |
228 | * @nr_pages: number of pages from start to pin | |
229 | * @write: whether pages will be written to | |
230 | * @pages: array that receives pointers to the pages pinned. | |
231 | * Should be at least nr_pages long. | |
232 | * | |
9de100d0 AG |
233 | * Returns number of pages pinned. This may be fewer than the number |
234 | * requested. If nr_pages is 0 or negative, returns 0. If no pages | |
235 | * were pinned, returns -errno. | |
d2bf6be8 NP |
236 | * |
237 | * get_user_pages_fast provides equivalent functionality to get_user_pages, | |
238 | * operating on current and current->mm, with force=0 and vma=NULL. However | |
239 | * unlike get_user_pages, it must be called without mmap_sem held. | |
240 | * | |
241 | * get_user_pages_fast may take mmap_sem and page table locks, so no | |
242 | * assumptions can be made about lack of locking. get_user_pages_fast is to be | |
243 | * implemented in a way that is advantageous (vs get_user_pages()) when the | |
244 | * user memory area is already faulted in and present in ptes. However if the | |
245 | * pages have to be faulted in, it may turn out to be slightly slower so | |
246 | * callers need to carefully consider what to use. On many architectures, | |
247 | * get_user_pages_fast simply falls back to get_user_pages. | |
9de100d0 | 248 | */ |
3b32123d | 249 | int __weak get_user_pages_fast(unsigned long start, |
912985dc RR |
250 | int nr_pages, int write, struct page **pages) |
251 | { | |
252 | struct mm_struct *mm = current->mm; | |
253 | int ret; | |
254 | ||
255 | down_read(&mm->mmap_sem); | |
256 | ret = get_user_pages(current, mm, start, nr_pages, | |
257 | write, 0, pages, NULL); | |
258 | up_read(&mm->mmap_sem); | |
259 | ||
260 | return ret; | |
261 | } | |
262 | EXPORT_SYMBOL_GPL(get_user_pages_fast); | |
ca2b84cb | 263 | |
eb36c587 AV |
264 | unsigned long vm_mmap_pgoff(struct file *file, unsigned long addr, |
265 | unsigned long len, unsigned long prot, | |
266 | unsigned long flag, unsigned long pgoff) | |
267 | { | |
268 | unsigned long ret; | |
269 | struct mm_struct *mm = current->mm; | |
41badc15 | 270 | unsigned long populate; |
eb36c587 AV |
271 | |
272 | ret = security_mmap_file(file, prot, flag); | |
273 | if (!ret) { | |
274 | down_write(&mm->mmap_sem); | |
bebeb3d6 ML |
275 | ret = do_mmap_pgoff(file, addr, len, prot, flag, pgoff, |
276 | &populate); | |
eb36c587 | 277 | up_write(&mm->mmap_sem); |
41badc15 ML |
278 | if (populate) |
279 | mm_populate(ret, populate); | |
eb36c587 AV |
280 | } |
281 | return ret; | |
282 | } | |
283 | ||
284 | unsigned long vm_mmap(struct file *file, unsigned long addr, | |
285 | unsigned long len, unsigned long prot, | |
286 | unsigned long flag, unsigned long offset) | |
287 | { | |
288 | if (unlikely(offset + PAGE_ALIGN(len) < offset)) | |
289 | return -EINVAL; | |
290 | if (unlikely(offset & ~PAGE_MASK)) | |
291 | return -EINVAL; | |
292 | ||
293 | return vm_mmap_pgoff(file, addr, len, prot, flag, offset >> PAGE_SHIFT); | |
294 | } | |
295 | EXPORT_SYMBOL(vm_mmap); | |
296 | ||
39f1f78d AV |
297 | void kvfree(const void *addr) |
298 | { | |
299 | if (is_vmalloc_addr(addr)) | |
300 | vfree(addr); | |
301 | else | |
302 | kfree(addr); | |
303 | } | |
304 | EXPORT_SYMBOL(kvfree); | |
305 | ||
9800339b SL |
306 | struct address_space *page_mapping(struct page *page) |
307 | { | |
308 | struct address_space *mapping = page->mapping; | |
309 | ||
03e5ac2f MP |
310 | /* This happens if someone calls flush_dcache_page on slab page */ |
311 | if (unlikely(PageSlab(page))) | |
312 | return NULL; | |
313 | ||
33806f06 SL |
314 | if (unlikely(PageSwapCache(page))) { |
315 | swp_entry_t entry; | |
316 | ||
317 | entry.val = page_private(page); | |
318 | mapping = swap_address_space(entry); | |
d2cf5ad6 | 319 | } else if ((unsigned long)mapping & PAGE_MAPPING_ANON) |
9800339b SL |
320 | mapping = NULL; |
321 | return mapping; | |
322 | } | |
323 | ||
49f0ce5f JM |
324 | int overcommit_ratio_handler(struct ctl_table *table, int write, |
325 | void __user *buffer, size_t *lenp, | |
326 | loff_t *ppos) | |
327 | { | |
328 | int ret; | |
329 | ||
330 | ret = proc_dointvec(table, write, buffer, lenp, ppos); | |
331 | if (ret == 0 && write) | |
332 | sysctl_overcommit_kbytes = 0; | |
333 | return ret; | |
334 | } | |
335 | ||
336 | int overcommit_kbytes_handler(struct ctl_table *table, int write, | |
337 | void __user *buffer, size_t *lenp, | |
338 | loff_t *ppos) | |
339 | { | |
340 | int ret; | |
341 | ||
342 | ret = proc_doulongvec_minmax(table, write, buffer, lenp, ppos); | |
343 | if (ret == 0 && write) | |
344 | sysctl_overcommit_ratio = 0; | |
345 | return ret; | |
346 | } | |
347 | ||
00619bcc JM |
348 | /* |
349 | * Committed memory limit enforced when OVERCOMMIT_NEVER policy is used | |
350 | */ | |
351 | unsigned long vm_commit_limit(void) | |
352 | { | |
49f0ce5f JM |
353 | unsigned long allowed; |
354 | ||
355 | if (sysctl_overcommit_kbytes) | |
356 | allowed = sysctl_overcommit_kbytes >> (PAGE_SHIFT - 10); | |
357 | else | |
358 | allowed = ((totalram_pages - hugetlb_total_pages()) | |
359 | * sysctl_overcommit_ratio / 100); | |
360 | allowed += total_swap_pages; | |
361 | ||
362 | return allowed; | |
00619bcc JM |
363 | } |
364 | ||
a9090253 WR |
365 | /** |
366 | * get_cmdline() - copy the cmdline value to a buffer. | |
367 | * @task: the task whose cmdline value to copy. | |
368 | * @buffer: the buffer to copy to. | |
369 | * @buflen: the length of the buffer. Larger cmdline values are truncated | |
370 | * to this length. | |
371 | * Returns the size of the cmdline field copied. Note that the copy does | |
372 | * not guarantee an ending NULL byte. | |
373 | */ | |
374 | int get_cmdline(struct task_struct *task, char *buffer, int buflen) | |
375 | { | |
376 | int res = 0; | |
377 | unsigned int len; | |
378 | struct mm_struct *mm = get_task_mm(task); | |
379 | if (!mm) | |
380 | goto out; | |
381 | if (!mm->arg_end) | |
382 | goto out_mm; /* Shh! No looking before we're done */ | |
383 | ||
384 | len = mm->arg_end - mm->arg_start; | |
385 | ||
386 | if (len > buflen) | |
387 | len = buflen; | |
388 | ||
389 | res = access_process_vm(task, mm->arg_start, buffer, len, 0); | |
390 | ||
391 | /* | |
392 | * If the nul at the end of args has been overwritten, then | |
393 | * assume application is using setproctitle(3). | |
394 | */ | |
395 | if (res > 0 && buffer[res-1] != '\0' && len < buflen) { | |
396 | len = strnlen(buffer, res); | |
397 | if (len < res) { | |
398 | res = len; | |
399 | } else { | |
400 | len = mm->env_end - mm->env_start; | |
401 | if (len > buflen - res) | |
402 | len = buflen - res; | |
403 | res += access_process_vm(task, mm->env_start, | |
404 | buffer+res, len, 0); | |
405 | res = strnlen(buffer, res); | |
406 | } | |
407 | } | |
408 | out_mm: | |
409 | mmput(mm); | |
410 | out: | |
411 | return res; | |
412 | } |