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Linux 2.6.31.6
[linux/fpc-iii.git] / fs / proc / kcore.c
blob5fd7d2b3da822bc56d2ddca71f622db7eda5ba80
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
12 #include <linux/mm.h>
13 #include <linux/proc_fs.h>
14 #include <linux/user.h>
15 #include <linux/capability.h>
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
24 #define CORE_STR "CORE"
25
26 #ifndef ELF_CORE_EFLAGS
27 #define ELF_CORE_EFLAGS 0
28 #endif
29
30 static struct proc_dir_entry *proc_root_kcore;
31
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
39 static const struct file_operations proc_kcore_operations = {
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
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) +
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);
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);
110 sz += roundup((strlen(en->name) + 1), 4);
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
126 en.n_namesz = strlen(men->name) + 1;
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;
173 elf->e_flags = ELF_CORE_EFLAGS;
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 */
216 notes[0].name = CORE_STR;
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(&notes[0]);
224 bufp = storenote(&notes[0], bufp);
225
226 /* set up the process info */
227 notes[1].name = CORE_STR;
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(&notes[1]);
241 bufp = storenote(&notes[1], bufp);
242
243 /* set up the task structure */
244 notes[2].name = CORE_STR;
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(&notes[2]);
250 bufp = storenote(&notes[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;
285 elf_buf = kzalloc(elf_buflen, GFP_ATOMIC);
286 if (!elf_buf) {
287 read_unlock(&kclist_lock);
288 return -ENOMEM;
289 }
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;
329 } else if (is_vmalloc_addr((void *)start)) {
330 char * elf_buf;
331 struct vm_struct *m;
332 unsigned long curstart = start;
333 unsigned long cursize = tsz;
334
335 elf_buf = kzalloc(tsz, GFP_KERNEL);
336 if (!elf_buf)
337 return -ENOMEM;
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 /*
365 * we may access memory holes, then use
366 * ex_table. checking return value just for
367 * avoid warnings.
368 */
369 vmsize = __copy_from_user_inatomic(
370 elf_buf + (vmstart - start),
371 (char *)vmstart, vmsize);
372 }
373 read_unlock(&vmlist_lock);
374 if (copy_to_user(buffer, elf_buf, tsz)) {
375 kfree(elf_buf);
376 return -EFAULT;
377 }
378 kfree(elf_buf);
379 } else {
380 if (kern_addr_valid(start)) {
381 unsigned long n;
382
383 n = copy_to_user(buffer, (char *)start, tsz);
384 /*
385 * We cannot distingush between fault on source
386 * and fault on destination. When this happens
387 * we clear too and hope it will trigger the
388 * EFAULT again.
389 */
390 if (n) {
391 if (clear_user(buffer + tsz - n,
392 n))
393 return -EFAULT;
394 }
395 } else {
396 if (clear_user(buffer, tsz))
397 return -EFAULT;
398 }
399 }
400 buflen -= tsz;
401 *fpos += tsz;
402 buffer += tsz;
403 acc += tsz;
404 start += tsz;
405 tsz = (buflen > PAGE_SIZE ? PAGE_SIZE : buflen);
406 }
407
408 return acc;
409 }
410
411 static int __init proc_kcore_init(void)
412 {
413 proc_root_kcore = proc_create("kcore", S_IRUSR, NULL, &proc_kcore_operations);
414 if (proc_root_kcore)
415 proc_root_kcore->size =
416 (size_t)high_memory - PAGE_OFFSET + PAGE_SIZE;
417 return 0;
418 }
419 module_init(proc_kcore_init);
Linux with added FPC-III support