Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * fs/proc/kcore.c kernel ELF core dumper | |
3 | * | |
4 | * Modelled on fs/exec.c:aout_core_dump() | |
5 | * Jeremy Fitzhardinge <jeremy@sw.oz.au> | |
6 | * ELF version written by David Howells <David.Howells@nexor.co.uk> | |
7 | * Modified and incorporated into 2.3.x by Tigran Aivazian <tigran@veritas.com> | |
8 | * Support to dump vmalloc'd areas (ELF only), Tigran Aivazian <tigran@veritas.com> | |
9 | * Safe accesses to vmalloc/direct-mapped discontiguous areas, Kanoj Sarcar <kanoj@sgi.com> | |
10 | */ | |
11 | ||
1da177e4 LT |
12 | #include <linux/mm.h> |
13 | #include <linux/proc_fs.h> | |
14 | #include <linux/user.h> | |
16f7e0fe | 15 | #include <linux/capability.h> |
1da177e4 LT |
16 | #include <linux/elf.h> |
17 | #include <linux/elfcore.h> | |
18 | #include <linux/vmalloc.h> | |
19 | #include <linux/highmem.h> | |
20 | #include <linux/init.h> | |
21 | #include <asm/uaccess.h> | |
22 | #include <asm/io.h> | |
23 | ||
36027604 | 24 | #define CORE_STR "CORE" |
1da177e4 | 25 | |
79885b22 EI |
26 | #ifndef ELF_CORE_EFLAGS |
27 | #define ELF_CORE_EFLAGS 0 | |
28 | #endif | |
29 | ||
97ce5d6d AD |
30 | static struct proc_dir_entry *proc_root_kcore; |
31 | ||
1da177e4 LT |
32 | static int open_kcore(struct inode * inode, struct file * filp) |
33 | { | |
34 | return capable(CAP_SYS_RAWIO) ? 0 : -EPERM; | |
35 | } | |
36 | ||
37 | static ssize_t read_kcore(struct file *, char __user *, size_t, loff_t *); | |
38 | ||
97ce5d6d | 39 | static const struct file_operations proc_kcore_operations = { |
1da177e4 LT |
40 | .read = read_kcore, |
41 | .open = open_kcore, | |
42 | }; | |
43 | ||
44 | #ifndef kc_vaddr_to_offset | |
45 | #define kc_vaddr_to_offset(v) ((v) - PAGE_OFFSET) | |
46 | #endif | |
47 | #ifndef kc_offset_to_vaddr | |
48 | #define kc_offset_to_vaddr(o) ((o) + PAGE_OFFSET) | |
49 | #endif | |
50 | ||
1da177e4 LT |
51 | /* An ELF note in memory */ |
52 | struct memelfnote | |
53 | { | |
54 | const char *name; | |
55 | int type; | |
56 | unsigned int datasz; | |
57 | void *data; | |
58 | }; | |
59 | ||
60 | static struct kcore_list *kclist; | |
61 | static DEFINE_RWLOCK(kclist_lock); | |
62 | ||
63 | void | |
64 | kclist_add(struct kcore_list *new, void *addr, size_t size) | |
65 | { | |
66 | new->addr = (unsigned long)addr; | |
67 | new->size = size; | |
68 | ||
69 | write_lock(&kclist_lock); | |
70 | new->next = kclist; | |
71 | kclist = new; | |
72 | write_unlock(&kclist_lock); | |
73 | } | |
74 | ||
75 | static size_t get_kcore_size(int *nphdr, size_t *elf_buflen) | |
76 | { | |
77 | size_t try, size; | |
78 | struct kcore_list *m; | |
79 | ||
80 | *nphdr = 1; /* PT_NOTE */ | |
81 | size = 0; | |
82 | ||
83 | for (m=kclist; m; m=m->next) { | |
84 | try = kc_vaddr_to_offset((size_t)m->addr + m->size); | |
85 | if (try > size) | |
86 | size = try; | |
87 | *nphdr = *nphdr + 1; | |
88 | } | |
89 | *elf_buflen = sizeof(struct elfhdr) + | |
90 | (*nphdr + 2)*sizeof(struct elf_phdr) + | |
36027604 MD |
91 | 3 * ((sizeof(struct elf_note)) + |
92 | roundup(sizeof(CORE_STR), 4)) + | |
93 | roundup(sizeof(struct elf_prstatus), 4) + | |
94 | roundup(sizeof(struct elf_prpsinfo), 4) + | |
95 | roundup(sizeof(struct task_struct), 4); | |
1da177e4 LT |
96 | *elf_buflen = PAGE_ALIGN(*elf_buflen); |
97 | return size + *elf_buflen; | |
98 | } | |
99 | ||
100 | ||
101 | /*****************************************************************************/ | |
102 | /* | |
103 | * determine size of ELF note | |
104 | */ | |
105 | static int notesize(struct memelfnote *en) | |
106 | { | |
107 | int sz; | |
108 | ||
109 | sz = sizeof(struct elf_note); | |
632dd205 | 110 | sz += roundup((strlen(en->name) + 1), 4); |
1da177e4 LT |
111 | sz += roundup(en->datasz, 4); |
112 | ||
113 | return sz; | |
114 | } /* end notesize() */ | |
115 | ||
116 | /*****************************************************************************/ | |
117 | /* | |
118 | * store a note in the header buffer | |
119 | */ | |
120 | static char *storenote(struct memelfnote *men, char *bufp) | |
121 | { | |
122 | struct elf_note en; | |
123 | ||
124 | #define DUMP_WRITE(addr,nr) do { memcpy(bufp,addr,nr); bufp += nr; } while(0) | |
125 | ||
632dd205 | 126 | en.n_namesz = strlen(men->name) + 1; |
1da177e4 LT |
127 | en.n_descsz = men->datasz; |
128 | en.n_type = men->type; | |
129 | ||
130 | DUMP_WRITE(&en, sizeof(en)); | |
131 | DUMP_WRITE(men->name, en.n_namesz); | |
132 | ||
133 | /* XXX - cast from long long to long to avoid need for libgcc.a */ | |
134 | bufp = (char*) roundup((unsigned long)bufp,4); | |
135 | DUMP_WRITE(men->data, men->datasz); | |
136 | bufp = (char*) roundup((unsigned long)bufp,4); | |
137 | ||
138 | #undef DUMP_WRITE | |
139 | ||
140 | return bufp; | |
141 | } /* end storenote() */ | |
142 | ||
143 | /* | |
144 | * store an ELF coredump header in the supplied buffer | |
145 | * nphdr is the number of elf_phdr to insert | |
146 | */ | |
147 | static void elf_kcore_store_hdr(char *bufp, int nphdr, int dataoff) | |
148 | { | |
149 | struct elf_prstatus prstatus; /* NT_PRSTATUS */ | |
150 | struct elf_prpsinfo prpsinfo; /* NT_PRPSINFO */ | |
151 | struct elf_phdr *nhdr, *phdr; | |
152 | struct elfhdr *elf; | |
153 | struct memelfnote notes[3]; | |
154 | off_t offset = 0; | |
155 | struct kcore_list *m; | |
156 | ||
157 | /* setup ELF header */ | |
158 | elf = (struct elfhdr *) bufp; | |
159 | bufp += sizeof(struct elfhdr); | |
160 | offset += sizeof(struct elfhdr); | |
161 | memcpy(elf->e_ident, ELFMAG, SELFMAG); | |
162 | elf->e_ident[EI_CLASS] = ELF_CLASS; | |
163 | elf->e_ident[EI_DATA] = ELF_DATA; | |
164 | elf->e_ident[EI_VERSION]= EV_CURRENT; | |
165 | elf->e_ident[EI_OSABI] = ELF_OSABI; | |
166 | memset(elf->e_ident+EI_PAD, 0, EI_NIDENT-EI_PAD); | |
167 | elf->e_type = ET_CORE; | |
168 | elf->e_machine = ELF_ARCH; | |
169 | elf->e_version = EV_CURRENT; | |
170 | elf->e_entry = 0; | |
171 | elf->e_phoff = sizeof(struct elfhdr); | |
172 | elf->e_shoff = 0; | |
79885b22 | 173 | elf->e_flags = ELF_CORE_EFLAGS; |
1da177e4 LT |
174 | elf->e_ehsize = sizeof(struct elfhdr); |
175 | elf->e_phentsize= sizeof(struct elf_phdr); | |
176 | elf->e_phnum = nphdr; | |
177 | elf->e_shentsize= 0; | |
178 | elf->e_shnum = 0; | |
179 | elf->e_shstrndx = 0; | |
180 | ||
181 | /* setup ELF PT_NOTE program header */ | |
182 | nhdr = (struct elf_phdr *) bufp; | |
183 | bufp += sizeof(struct elf_phdr); | |
184 | offset += sizeof(struct elf_phdr); | |
185 | nhdr->p_type = PT_NOTE; | |
186 | nhdr->p_offset = 0; | |
187 | nhdr->p_vaddr = 0; | |
188 | nhdr->p_paddr = 0; | |
189 | nhdr->p_filesz = 0; | |
190 | nhdr->p_memsz = 0; | |
191 | nhdr->p_flags = 0; | |
192 | nhdr->p_align = 0; | |
193 | ||
194 | /* setup ELF PT_LOAD program header for every area */ | |
195 | for (m=kclist; m; m=m->next) { | |
196 | phdr = (struct elf_phdr *) bufp; | |
197 | bufp += sizeof(struct elf_phdr); | |
198 | offset += sizeof(struct elf_phdr); | |
199 | ||
200 | phdr->p_type = PT_LOAD; | |
201 | phdr->p_flags = PF_R|PF_W|PF_X; | |
202 | phdr->p_offset = kc_vaddr_to_offset(m->addr) + dataoff; | |
203 | phdr->p_vaddr = (size_t)m->addr; | |
204 | phdr->p_paddr = 0; | |
205 | phdr->p_filesz = phdr->p_memsz = m->size; | |
206 | phdr->p_align = PAGE_SIZE; | |
207 | } | |
208 | ||
209 | /* | |
210 | * Set up the notes in similar form to SVR4 core dumps made | |
211 | * with info from their /proc. | |
212 | */ | |
213 | nhdr->p_offset = offset; | |
214 | ||
215 | /* set up the process status */ | |
36027604 | 216 | notes[0].name = CORE_STR; |
1da177e4 LT |
217 | notes[0].type = NT_PRSTATUS; |
218 | notes[0].datasz = sizeof(struct elf_prstatus); | |
219 | notes[0].data = &prstatus; | |
220 | ||
221 | memset(&prstatus, 0, sizeof(struct elf_prstatus)); | |
222 | ||
223 | nhdr->p_filesz = notesize(¬es[0]); | |
224 | bufp = storenote(¬es[0], bufp); | |
225 | ||
226 | /* set up the process info */ | |
36027604 | 227 | notes[1].name = CORE_STR; |
1da177e4 LT |
228 | notes[1].type = NT_PRPSINFO; |
229 | notes[1].datasz = sizeof(struct elf_prpsinfo); | |
230 | notes[1].data = &prpsinfo; | |
231 | ||
232 | memset(&prpsinfo, 0, sizeof(struct elf_prpsinfo)); | |
233 | prpsinfo.pr_state = 0; | |
234 | prpsinfo.pr_sname = 'R'; | |
235 | prpsinfo.pr_zomb = 0; | |
236 | ||
237 | strcpy(prpsinfo.pr_fname, "vmlinux"); | |
238 | strncpy(prpsinfo.pr_psargs, saved_command_line, ELF_PRARGSZ); | |
239 | ||
240 | nhdr->p_filesz += notesize(¬es[1]); | |
241 | bufp = storenote(¬es[1], bufp); | |
242 | ||
243 | /* set up the task structure */ | |
36027604 | 244 | notes[2].name = CORE_STR; |
1da177e4 LT |
245 | notes[2].type = NT_TASKSTRUCT; |
246 | notes[2].datasz = sizeof(struct task_struct); | |
247 | notes[2].data = current; | |
248 | ||
249 | nhdr->p_filesz += notesize(¬es[2]); | |
250 | bufp = storenote(¬es[2], bufp); | |
251 | ||
252 | } /* end elf_kcore_store_hdr() */ | |
253 | ||
254 | /*****************************************************************************/ | |
255 | /* | |
256 | * read from the ELF header and then kernel memory | |
257 | */ | |
258 | static ssize_t | |
259 | read_kcore(struct file *file, char __user *buffer, size_t buflen, loff_t *fpos) | |
260 | { | |
261 | ssize_t acc = 0; | |
262 | size_t size, tsz; | |
263 | size_t elf_buflen; | |
264 | int nphdr; | |
265 | unsigned long start; | |
266 | ||
267 | read_lock(&kclist_lock); | |
268 | proc_root_kcore->size = size = get_kcore_size(&nphdr, &elf_buflen); | |
269 | if (buflen == 0 || *fpos >= size) { | |
270 | read_unlock(&kclist_lock); | |
271 | return 0; | |
272 | } | |
273 | ||
274 | /* trim buflen to not go beyond EOF */ | |
275 | if (buflen > size - *fpos) | |
276 | buflen = size - *fpos; | |
277 | ||
278 | /* construct an ELF core header if we'll need some of it */ | |
279 | if (*fpos < elf_buflen) { | |
280 | char * elf_buf; | |
281 | ||
282 | tsz = elf_buflen - *fpos; | |
283 | if (buflen < tsz) | |
284 | tsz = buflen; | |
f8314dc6 | 285 | elf_buf = kzalloc(elf_buflen, GFP_ATOMIC); |
1da177e4 LT |
286 | if (!elf_buf) { |
287 | read_unlock(&kclist_lock); | |
288 | return -ENOMEM; | |
289 | } | |
1da177e4 LT |
290 | elf_kcore_store_hdr(elf_buf, nphdr, elf_buflen); |
291 | read_unlock(&kclist_lock); | |
292 | if (copy_to_user(buffer, elf_buf + *fpos, tsz)) { | |
293 | kfree(elf_buf); | |
294 | return -EFAULT; | |
295 | } | |
296 | kfree(elf_buf); | |
297 | buflen -= tsz; | |
298 | *fpos += tsz; | |
299 | buffer += tsz; | |
300 | acc += tsz; | |
301 | ||
302 | /* leave now if filled buffer already */ | |
303 | if (buflen == 0) | |
304 | return acc; | |
305 | } else | |
306 | read_unlock(&kclist_lock); | |
307 | ||
308 | /* | |
309 | * Check to see if our file offset matches with any of | |
310 | * the addresses in the elf_phdr on our list. | |
311 | */ | |
312 | start = kc_offset_to_vaddr(*fpos - elf_buflen); | |
313 | if ((tsz = (PAGE_SIZE - (start & ~PAGE_MASK))) > buflen) | |
314 | tsz = buflen; | |
315 | ||
316 | while (buflen) { | |
317 | struct kcore_list *m; | |
318 | ||
319 | read_lock(&kclist_lock); | |
320 | for (m=kclist; m; m=m->next) { | |
321 | if (start >= m->addr && start < (m->addr+m->size)) | |
322 | break; | |
323 | } | |
324 | read_unlock(&kclist_lock); | |
325 | ||
326 | if (m == NULL) { | |
327 | if (clear_user(buffer, tsz)) | |
328 | return -EFAULT; | |
9e2779fa | 329 | } else if (is_vmalloc_addr((void *)start)) { |
1da177e4 LT |
330 | char * elf_buf; |
331 | struct vm_struct *m; | |
332 | unsigned long curstart = start; | |
333 | unsigned long cursize = tsz; | |
334 | ||
f8314dc6 | 335 | elf_buf = kzalloc(tsz, GFP_KERNEL); |
1da177e4 LT |
336 | if (!elf_buf) |
337 | return -ENOMEM; | |
1da177e4 LT |
338 | |
339 | read_lock(&vmlist_lock); | |
340 | for (m=vmlist; m && cursize; m=m->next) { | |
341 | unsigned long vmstart; | |
342 | unsigned long vmsize; | |
343 | unsigned long msize = m->size - PAGE_SIZE; | |
344 | ||
345 | if (((unsigned long)m->addr + msize) < | |
346 | curstart) | |
347 | continue; | |
348 | if ((unsigned long)m->addr > (curstart + | |
349 | cursize)) | |
350 | break; | |
351 | vmstart = (curstart < (unsigned long)m->addr ? | |
352 | (unsigned long)m->addr : curstart); | |
353 | if (((unsigned long)m->addr + msize) > | |
354 | (curstart + cursize)) | |
355 | vmsize = curstart + cursize - vmstart; | |
356 | else | |
357 | vmsize = (unsigned long)m->addr + | |
358 | msize - vmstart; | |
359 | curstart = vmstart + vmsize; | |
360 | cursize -= vmsize; | |
361 | /* don't dump ioremap'd stuff! (TA) */ | |
362 | if (m->flags & VM_IOREMAP) | |
363 | continue; | |
364 | memcpy(elf_buf + (vmstart - start), | |
365 | (char *)vmstart, vmsize); | |
366 | } | |
367 | read_unlock(&vmlist_lock); | |
368 | if (copy_to_user(buffer, elf_buf, tsz)) { | |
369 | kfree(elf_buf); | |
370 | return -EFAULT; | |
371 | } | |
372 | kfree(elf_buf); | |
373 | } else { | |
374 | if (kern_addr_valid(start)) { | |
375 | unsigned long n; | |
376 | ||
377 | n = copy_to_user(buffer, (char *)start, tsz); | |
378 | /* | |
379 | * We cannot distingush between fault on source | |
380 | * and fault on destination. When this happens | |
381 | * we clear too and hope it will trigger the | |
382 | * EFAULT again. | |
383 | */ | |
384 | if (n) { | |
385 | if (clear_user(buffer + tsz - n, | |
0635170b | 386 | n)) |
1da177e4 LT |
387 | return -EFAULT; |
388 | } | |
389 | } else { | |
390 | if (clear_user(buffer, tsz)) | |
391 | return -EFAULT; | |
392 | } | |
393 | } | |
394 | buflen -= tsz; | |
395 | *fpos += tsz; | |
396 | buffer += tsz; | |
397 | acc += tsz; | |
398 | start += tsz; | |
399 | tsz = (buflen > PAGE_SIZE ? PAGE_SIZE : buflen); | |
400 | } | |
401 | ||
402 | return acc; | |
403 | } | |
97ce5d6d AD |
404 | |
405 | static int __init proc_kcore_init(void) | |
406 | { | |
407 | proc_root_kcore = proc_create("kcore", S_IRUSR, NULL, &proc_kcore_operations); | |
408 | if (proc_root_kcore) | |
409 | proc_root_kcore->size = | |
410 | (size_t)high_memory - PAGE_OFFSET + PAGE_SIZE; | |
411 | return 0; | |
412 | } | |
413 | module_init(proc_kcore_init); |