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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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
Linus Torvalds1da177e2005-04-16 15:20:36 -070012#include <linux/mm.h>
13#include <linux/proc_fs.h>
14#include <linux/user.h>
Randy Dunlap16f7e0f2006-01-11 12:17:46 -080015#include <linux/capability.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070016#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
Magnus Damm36027602006-12-06 20:38:00 -080024#define CORE_STR "CORE"
Linus Torvalds1da177e2005-04-16 15:20:36 -070025
26static int open_kcore(struct inode * inode, struct file * filp)
27{
28 return capable(CAP_SYS_RAWIO) ? 0 : -EPERM;
29}
30
31static ssize_t read_kcore(struct file *, char __user *, size_t, loff_t *);
32
Arjan van de Ven4b6f5d22006-03-28 01:56:42 -080033const struct file_operations proc_kcore_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -070034 .read = read_kcore,
35 .open = open_kcore,
36};
37
38#ifndef kc_vaddr_to_offset
39#define kc_vaddr_to_offset(v) ((v) - PAGE_OFFSET)
40#endif
41#ifndef kc_offset_to_vaddr
42#define kc_offset_to_vaddr(o) ((o) + PAGE_OFFSET)
43#endif
44
Linus Torvalds1da177e2005-04-16 15:20:36 -070045/* An ELF note in memory */
46struct memelfnote
47{
48 const char *name;
49 int type;
50 unsigned int datasz;
51 void *data;
52};
53
54static struct kcore_list *kclist;
55static DEFINE_RWLOCK(kclist_lock);
56
57void
58kclist_add(struct kcore_list *new, void *addr, size_t size)
59{
60 new->addr = (unsigned long)addr;
61 new->size = size;
62
63 write_lock(&kclist_lock);
64 new->next = kclist;
65 kclist = new;
66 write_unlock(&kclist_lock);
67}
68
69static size_t get_kcore_size(int *nphdr, size_t *elf_buflen)
70{
71 size_t try, size;
72 struct kcore_list *m;
73
74 *nphdr = 1; /* PT_NOTE */
75 size = 0;
76
77 for (m=kclist; m; m=m->next) {
78 try = kc_vaddr_to_offset((size_t)m->addr + m->size);
79 if (try > size)
80 size = try;
81 *nphdr = *nphdr + 1;
82 }
83 *elf_buflen = sizeof(struct elfhdr) +
84 (*nphdr + 2)*sizeof(struct elf_phdr) +
Magnus Damm36027602006-12-06 20:38:00 -080085 3 * ((sizeof(struct elf_note)) +
86 roundup(sizeof(CORE_STR), 4)) +
87 roundup(sizeof(struct elf_prstatus), 4) +
88 roundup(sizeof(struct elf_prpsinfo), 4) +
89 roundup(sizeof(struct task_struct), 4);
Linus Torvalds1da177e2005-04-16 15:20:36 -070090 *elf_buflen = PAGE_ALIGN(*elf_buflen);
91 return size + *elf_buflen;
92}
93
94
95/*****************************************************************************/
96/*
97 * determine size of ELF note
98 */
99static int notesize(struct memelfnote *en)
100{
101 int sz;
102
103 sz = sizeof(struct elf_note);
Vivek Goyal632dd202006-09-29 02:01:45 -0700104 sz += roundup((strlen(en->name) + 1), 4);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700105 sz += roundup(en->datasz, 4);
106
107 return sz;
108} /* end notesize() */
109
110/*****************************************************************************/
111/*
112 * store a note in the header buffer
113 */
114static char *storenote(struct memelfnote *men, char *bufp)
115{
116 struct elf_note en;
117
118#define DUMP_WRITE(addr,nr) do { memcpy(bufp,addr,nr); bufp += nr; } while(0)
119
Vivek Goyal632dd202006-09-29 02:01:45 -0700120 en.n_namesz = strlen(men->name) + 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700121 en.n_descsz = men->datasz;
122 en.n_type = men->type;
123
124 DUMP_WRITE(&en, sizeof(en));
125 DUMP_WRITE(men->name, en.n_namesz);
126
127 /* XXX - cast from long long to long to avoid need for libgcc.a */
128 bufp = (char*) roundup((unsigned long)bufp,4);
129 DUMP_WRITE(men->data, men->datasz);
130 bufp = (char*) roundup((unsigned long)bufp,4);
131
132#undef DUMP_WRITE
133
134 return bufp;
135} /* end storenote() */
136
137/*
138 * store an ELF coredump header in the supplied buffer
139 * nphdr is the number of elf_phdr to insert
140 */
141static void elf_kcore_store_hdr(char *bufp, int nphdr, int dataoff)
142{
143 struct elf_prstatus prstatus; /* NT_PRSTATUS */
144 struct elf_prpsinfo prpsinfo; /* NT_PRPSINFO */
145 struct elf_phdr *nhdr, *phdr;
146 struct elfhdr *elf;
147 struct memelfnote notes[3];
148 off_t offset = 0;
149 struct kcore_list *m;
150
151 /* setup ELF header */
152 elf = (struct elfhdr *) bufp;
153 bufp += sizeof(struct elfhdr);
154 offset += sizeof(struct elfhdr);
155 memcpy(elf->e_ident, ELFMAG, SELFMAG);
156 elf->e_ident[EI_CLASS] = ELF_CLASS;
157 elf->e_ident[EI_DATA] = ELF_DATA;
158 elf->e_ident[EI_VERSION]= EV_CURRENT;
159 elf->e_ident[EI_OSABI] = ELF_OSABI;
160 memset(elf->e_ident+EI_PAD, 0, EI_NIDENT-EI_PAD);
161 elf->e_type = ET_CORE;
162 elf->e_machine = ELF_ARCH;
163 elf->e_version = EV_CURRENT;
164 elf->e_entry = 0;
165 elf->e_phoff = sizeof(struct elfhdr);
166 elf->e_shoff = 0;
167#if defined(CONFIG_H8300)
168 elf->e_flags = ELF_FLAGS;
169#else
170 elf->e_flags = 0;
171#endif
172 elf->e_ehsize = sizeof(struct elfhdr);
173 elf->e_phentsize= sizeof(struct elf_phdr);
174 elf->e_phnum = nphdr;
175 elf->e_shentsize= 0;
176 elf->e_shnum = 0;
177 elf->e_shstrndx = 0;
178
179 /* setup ELF PT_NOTE program header */
180 nhdr = (struct elf_phdr *) bufp;
181 bufp += sizeof(struct elf_phdr);
182 offset += sizeof(struct elf_phdr);
183 nhdr->p_type = PT_NOTE;
184 nhdr->p_offset = 0;
185 nhdr->p_vaddr = 0;
186 nhdr->p_paddr = 0;
187 nhdr->p_filesz = 0;
188 nhdr->p_memsz = 0;
189 nhdr->p_flags = 0;
190 nhdr->p_align = 0;
191
192 /* setup ELF PT_LOAD program header for every area */
193 for (m=kclist; m; m=m->next) {
194 phdr = (struct elf_phdr *) bufp;
195 bufp += sizeof(struct elf_phdr);
196 offset += sizeof(struct elf_phdr);
197
198 phdr->p_type = PT_LOAD;
199 phdr->p_flags = PF_R|PF_W|PF_X;
200 phdr->p_offset = kc_vaddr_to_offset(m->addr) + dataoff;
201 phdr->p_vaddr = (size_t)m->addr;
202 phdr->p_paddr = 0;
203 phdr->p_filesz = phdr->p_memsz = m->size;
204 phdr->p_align = PAGE_SIZE;
205 }
206
207 /*
208 * Set up the notes in similar form to SVR4 core dumps made
209 * with info from their /proc.
210 */
211 nhdr->p_offset = offset;
212
213 /* set up the process status */
Magnus Damm36027602006-12-06 20:38:00 -0800214 notes[0].name = CORE_STR;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700215 notes[0].type = NT_PRSTATUS;
216 notes[0].datasz = sizeof(struct elf_prstatus);
217 notes[0].data = &prstatus;
218
219 memset(&prstatus, 0, sizeof(struct elf_prstatus));
220
221 nhdr->p_filesz = notesize(&notes[0]);
222 bufp = storenote(&notes[0], bufp);
223
224 /* set up the process info */
Magnus Damm36027602006-12-06 20:38:00 -0800225 notes[1].name = CORE_STR;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700226 notes[1].type = NT_PRPSINFO;
227 notes[1].datasz = sizeof(struct elf_prpsinfo);
228 notes[1].data = &prpsinfo;
229
230 memset(&prpsinfo, 0, sizeof(struct elf_prpsinfo));
231 prpsinfo.pr_state = 0;
232 prpsinfo.pr_sname = 'R';
233 prpsinfo.pr_zomb = 0;
234
235 strcpy(prpsinfo.pr_fname, "vmlinux");
236 strncpy(prpsinfo.pr_psargs, saved_command_line, ELF_PRARGSZ);
237
238 nhdr->p_filesz += notesize(&notes[1]);
239 bufp = storenote(&notes[1], bufp);
240
241 /* set up the task structure */
Magnus Damm36027602006-12-06 20:38:00 -0800242 notes[2].name = CORE_STR;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700243 notes[2].type = NT_TASKSTRUCT;
244 notes[2].datasz = sizeof(struct task_struct);
245 notes[2].data = current;
246
247 nhdr->p_filesz += notesize(&notes[2]);
248 bufp = storenote(&notes[2], bufp);
249
250} /* end elf_kcore_store_hdr() */
251
252/*****************************************************************************/
253/*
254 * read from the ELF header and then kernel memory
255 */
256static ssize_t
257read_kcore(struct file *file, char __user *buffer, size_t buflen, loff_t *fpos)
258{
259 ssize_t acc = 0;
260 size_t size, tsz;
261 size_t elf_buflen;
262 int nphdr;
263 unsigned long start;
264
265 read_lock(&kclist_lock);
266 proc_root_kcore->size = size = get_kcore_size(&nphdr, &elf_buflen);
267 if (buflen == 0 || *fpos >= size) {
268 read_unlock(&kclist_lock);
269 return 0;
270 }
271
272 /* trim buflen to not go beyond EOF */
273 if (buflen > size - *fpos)
274 buflen = size - *fpos;
275
276 /* construct an ELF core header if we'll need some of it */
277 if (*fpos < elf_buflen) {
278 char * elf_buf;
279
280 tsz = elf_buflen - *fpos;
281 if (buflen < tsz)
282 tsz = buflen;
Panagiotis Issarisf8314dc2006-09-27 01:49:37 -0700283 elf_buf = kzalloc(elf_buflen, GFP_ATOMIC);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700284 if (!elf_buf) {
285 read_unlock(&kclist_lock);
286 return -ENOMEM;
287 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700288 elf_kcore_store_hdr(elf_buf, nphdr, elf_buflen);
289 read_unlock(&kclist_lock);
290 if (copy_to_user(buffer, elf_buf + *fpos, tsz)) {
291 kfree(elf_buf);
292 return -EFAULT;
293 }
294 kfree(elf_buf);
295 buflen -= tsz;
296 *fpos += tsz;
297 buffer += tsz;
298 acc += tsz;
299
300 /* leave now if filled buffer already */
301 if (buflen == 0)
302 return acc;
303 } else
304 read_unlock(&kclist_lock);
305
306 /*
307 * Check to see if our file offset matches with any of
308 * the addresses in the elf_phdr on our list.
309 */
310 start = kc_offset_to_vaddr(*fpos - elf_buflen);
311 if ((tsz = (PAGE_SIZE - (start & ~PAGE_MASK))) > buflen)
312 tsz = buflen;
313
314 while (buflen) {
315 struct kcore_list *m;
316
317 read_lock(&kclist_lock);
318 for (m=kclist; m; m=m->next) {
319 if (start >= m->addr && start < (m->addr+m->size))
320 break;
321 }
322 read_unlock(&kclist_lock);
323
324 if (m == NULL) {
325 if (clear_user(buffer, tsz))
326 return -EFAULT;
Christoph Lameter9e2779f2008-02-04 22:28:34 -0800327 } else if (is_vmalloc_addr((void *)start)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700328 char * elf_buf;
329 struct vm_struct *m;
330 unsigned long curstart = start;
331 unsigned long cursize = tsz;
332
Panagiotis Issarisf8314dc2006-09-27 01:49:37 -0700333 elf_buf = kzalloc(tsz, GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700334 if (!elf_buf)
335 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700336
337 read_lock(&vmlist_lock);
338 for (m=vmlist; m && cursize; m=m->next) {
339 unsigned long vmstart;
340 unsigned long vmsize;
341 unsigned long msize = m->size - PAGE_SIZE;
342
343 if (((unsigned long)m->addr + msize) <
344 curstart)
345 continue;
346 if ((unsigned long)m->addr > (curstart +
347 cursize))
348 break;
349 vmstart = (curstart < (unsigned long)m->addr ?
350 (unsigned long)m->addr : curstart);
351 if (((unsigned long)m->addr + msize) >
352 (curstart + cursize))
353 vmsize = curstart + cursize - vmstart;
354 else
355 vmsize = (unsigned long)m->addr +
356 msize - vmstart;
357 curstart = vmstart + vmsize;
358 cursize -= vmsize;
359 /* don't dump ioremap'd stuff! (TA) */
360 if (m->flags & VM_IOREMAP)
361 continue;
362 memcpy(elf_buf + (vmstart - start),
363 (char *)vmstart, vmsize);
364 }
365 read_unlock(&vmlist_lock);
366 if (copy_to_user(buffer, elf_buf, tsz)) {
367 kfree(elf_buf);
368 return -EFAULT;
369 }
370 kfree(elf_buf);
371 } else {
372 if (kern_addr_valid(start)) {
373 unsigned long n;
374
375 n = copy_to_user(buffer, (char *)start, tsz);
376 /*
377 * We cannot distingush between fault on source
378 * and fault on destination. When this happens
379 * we clear too and hope it will trigger the
380 * EFAULT again.
381 */
382 if (n) {
383 if (clear_user(buffer + tsz - n,
Adam B. Jerome06351702006-07-12 09:03:07 -0700384 n))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700385 return -EFAULT;
386 }
387 } else {
388 if (clear_user(buffer, tsz))
389 return -EFAULT;
390 }
391 }
392 buflen -= tsz;
393 *fpos += tsz;
394 buffer += tsz;
395 acc += tsz;
396 start += tsz;
397 tsz = (buflen > PAGE_SIZE ? PAGE_SIZE : buflen);
398 }
399
400 return acc;
401}