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/config.h>
13 #include <linux/mm.h>
14 #include <linux/proc_fs.h>
15 #include <linux/user.h>
16 #include <linux/a.out.h>
17 #include <linux/elf.h>
18 #include <linux/elfcore.h>
19 #include <linux/vmalloc.h>
20 #include <linux/highmem.h>
21 #include <linux/init.h>
22 #include <asm/uaccess.h>
23 #include <asm/io.h>
24
25
26 static int open_kcore(struct inode * inode, struct file * filp)
27 {
28 return capable(CAP_SYS_RAWIO) ? 0 : -EPERM;
29 }
30
31 static ssize_t read_kcore(struct file *, char __user *, size_t, loff_t *);
32
33 struct file_operations proc_kcore_operations = {
34 .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
45 #define roundup(x, y) ((((x)+((y)-1))/(y))*(y))
46
47 /* An ELF note in memory */
48 struct memelfnote
49 {
50 const char *name;
51 int type;
52 unsigned int datasz;
53 void *data;
54 };
55
56 static struct kcore_list *kclist;
57 static DEFINE_RWLOCK(kclist_lock);
58
59 void
60 kclist_add(struct kcore_list *new, void *addr, size_t size)
61 {
62 new->addr = (unsigned long)addr;
63 new->size = size;
64
65 write_lock(&kclist_lock);
66 new->next = kclist;
67 kclist = new;
68 write_unlock(&kclist_lock);
69 }
70
71 static size_t get_kcore_size(int *nphdr, size_t *elf_buflen)
72 {
73 size_t try, size;
74 struct kcore_list *m;
75
76 *nphdr = 1; /* PT_NOTE */
77 size = 0;
78
79 for (m=kclist; m; m=m->next) {
80 try = kc_vaddr_to_offset((size_t)m->addr + m->size);
81 if (try > size)
82 size = try;
83 *nphdr = *nphdr + 1;
84 }
85 *elf_buflen = sizeof(struct elfhdr) +
86 (*nphdr + 2)*sizeof(struct elf_phdr) +
87 3 * sizeof(struct memelfnote) +
88 sizeof(struct elf_prstatus) +
89 sizeof(struct elf_prpsinfo) +
90 sizeof(struct task_struct);
91 *elf_buflen = PAGE_ALIGN(*elf_buflen);
92 return size + *elf_buflen;
93 }
94
95
96 /*****************************************************************************/
97 /*
98 * determine size of ELF note
99 */
100 static int notesize(struct memelfnote *en)
101 {
102 int sz;
103
104 sz = sizeof(struct elf_note);
105 sz += roundup(strlen(en->name), 4);
106 sz += roundup(en->datasz, 4);
107
108 return sz;
109 } /* end notesize() */
110
111 /*****************************************************************************/
112 /*
113 * store a note in the header buffer
114 */
115 static char *storenote(struct memelfnote *men, char *bufp)
116 {
117 struct elf_note en;
118
119 #define DUMP_WRITE(addr,nr) do { memcpy(bufp,addr,nr); bufp += nr; } while(0)
120
121 en.n_namesz = strlen(men->name);
122 en.n_descsz = men->datasz;
123 en.n_type = men->type;
124
125 DUMP_WRITE(&en, sizeof(en));
126 DUMP_WRITE(men->name, en.n_namesz);
127
128 /* XXX - cast from long long to long to avoid need for libgcc.a */
129 bufp = (char*) roundup((unsigned long)bufp,4);
130 DUMP_WRITE(men->data, men->datasz);
131 bufp = (char*) roundup((unsigned long)bufp,4);
132
133 #undef DUMP_WRITE
134
135 return bufp;
136 } /* end storenote() */
137
138 /*
139 * store an ELF coredump header in the supplied buffer
140 * nphdr is the number of elf_phdr to insert
141 */
142 static void elf_kcore_store_hdr(char *bufp, int nphdr, int dataoff)
143 {
144 struct elf_prstatus prstatus; /* NT_PRSTATUS */
145 struct elf_prpsinfo prpsinfo; /* NT_PRPSINFO */
146 struct elf_phdr *nhdr, *phdr;
147 struct elfhdr *elf;
148 struct memelfnote notes[3];
149 off_t offset = 0;
150 struct kcore_list *m;
151
152 /* setup ELF header */
153 elf = (struct elfhdr *) bufp;
154 bufp += sizeof(struct elfhdr);
155 offset += sizeof(struct elfhdr);
156 memcpy(elf->e_ident, ELFMAG, SELFMAG);
157 elf->e_ident[EI_CLASS] = ELF_CLASS;
158 elf->e_ident[EI_DATA] = ELF_DATA;
159 elf->e_ident[EI_VERSION]= EV_CURRENT;
160 elf->e_ident[EI_OSABI] = ELF_OSABI;
161 memset(elf->e_ident+EI_PAD, 0, EI_NIDENT-EI_PAD);
162 elf->e_type = ET_CORE;
163 elf->e_machine = ELF_ARCH;
164 elf->e_version = EV_CURRENT;
165 elf->e_entry = 0;
166 elf->e_phoff = sizeof(struct elfhdr);
167 elf->e_shoff = 0;
168 #if defined(CONFIG_H8300)
169 elf->e_flags = ELF_FLAGS;
170 #else
171 elf->e_flags = 0;
172 #endif
173 elf->e_ehsize = sizeof(struct elfhdr);
174 elf->e_phentsize= sizeof(struct elf_phdr);
175 elf->e_phnum = nphdr;
176 elf->e_shentsize= 0;
177 elf->e_shnum = 0;
178 elf->e_shstrndx = 0;
179
180 /* setup ELF PT_NOTE program header */
181 nhdr = (struct elf_phdr *) bufp;
182 bufp += sizeof(struct elf_phdr);
183 offset += sizeof(struct elf_phdr);
184 nhdr->p_type = PT_NOTE;
185 nhdr->p_offset = 0;
186 nhdr->p_vaddr = 0;
187 nhdr->p_paddr = 0;
188 nhdr->p_filesz = 0;
189 nhdr->p_memsz = 0;
190 nhdr->p_flags = 0;
191 nhdr->p_align = 0;
192
193 /* setup ELF PT_LOAD program header for every area */
194 for (m=kclist; m; m=m->next) {
195 phdr = (struct elf_phdr *) bufp;
196 bufp += sizeof(struct elf_phdr);
197 offset += sizeof(struct elf_phdr);
198
199 phdr->p_type = PT_LOAD;
200 phdr->p_flags = PF_R|PF_W|PF_X;
201 phdr->p_offset = kc_vaddr_to_offset(m->addr) + dataoff;
202 phdr->p_vaddr = (size_t)m->addr;
203 phdr->p_paddr = 0;
204 phdr->p_filesz = phdr->p_memsz = m->size;
205 phdr->p_align = PAGE_SIZE;
206 }
207
208 /*
209 * Set up the notes in similar form to SVR4 core dumps made
210 * with info from their /proc.
211 */
212 nhdr->p_offset = offset;
213
214 /* set up the process status */
215 notes[0].name = "CORE";
216 notes[0].type = NT_PRSTATUS;
217 notes[0].datasz = sizeof(struct elf_prstatus);
218 notes[0].data = &prstatus;
219
220 memset(&prstatus, 0, sizeof(struct elf_prstatus));
221
222 nhdr->p_filesz = notesize(¬es[0]);
223 bufp = storenote(¬es[0], bufp);
224
225 /* set up the process info */
226 notes[1].name = "CORE";
227 notes[1].type = NT_PRPSINFO;
228 notes[1].datasz = sizeof(struct elf_prpsinfo);
229 notes[1].data = &prpsinfo;
230
231 memset(&prpsinfo, 0, sizeof(struct elf_prpsinfo));
232 prpsinfo.pr_state = 0;
233 prpsinfo.pr_sname = 'R';
234 prpsinfo.pr_zomb = 0;
235
236 strcpy(prpsinfo.pr_fname, "vmlinux");
237 strncpy(prpsinfo.pr_psargs, saved_command_line, ELF_PRARGSZ);
238
239 nhdr->p_filesz += notesize(¬es[1]);
240 bufp = storenote(¬es[1], bufp);
241
242 /* set up the task structure */
243 notes[2].name = "CORE";
244 notes[2].type = NT_TASKSTRUCT;
245 notes[2].datasz = sizeof(struct task_struct);
246 notes[2].data = current;
247
248 nhdr->p_filesz += notesize(¬es[2]);
249 bufp = storenote(¬es[2], bufp);
250
251 } /* end elf_kcore_store_hdr() */
252
253 /*****************************************************************************/
254 /*
255 * read from the ELF header and then kernel memory
256 */
257 static ssize_t
258 read_kcore(struct file *file, char __user *buffer, size_t buflen, loff_t *fpos)
259 {
260 ssize_t acc = 0;
261 size_t size, tsz;
262 size_t elf_buflen;
263 int nphdr;
264 unsigned long start;
265
266 read_lock(&kclist_lock);
267 proc_root_kcore->size = size = get_kcore_size(&nphdr, &elf_buflen);
268 if (buflen == 0 || *fpos >= size) {
269 read_unlock(&kclist_lock);
270 return 0;
271 }
272
273 /* trim buflen to not go beyond EOF */
274 if (buflen > size - *fpos)
275 buflen = size - *fpos;
276
277 /* construct an ELF core header if we'll need some of it */
278 if (*fpos < elf_buflen) {
279 char * elf_buf;
280
281 tsz = elf_buflen - *fpos;
282 if (buflen < tsz)
283 tsz = buflen;
284 elf_buf = kmalloc(elf_buflen, GFP_ATOMIC);
285 if (!elf_buf) {
286 read_unlock(&kclist_lock);
287 return -ENOMEM;
288 }
289 memset(elf_buf, 0, elf_buflen);
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 ((start >= VMALLOC_START) && (start < VMALLOC_END)) {
330 char * elf_buf;
331 struct vm_struct *m;
332 unsigned long curstart = start;
333 unsigned long cursize = tsz;
334
335 elf_buf = kmalloc(tsz, GFP_KERNEL);
336 if (!elf_buf)
337 return -ENOMEM;
338 memset(elf_buf, 0, tsz);
339
340 read_lock(&vmlist_lock);
341 for (m=vmlist; m && cursize; m=m->next) {
342 unsigned long vmstart;
343 unsigned long vmsize;
344 unsigned long msize = m->size - PAGE_SIZE;
345
346 if (((unsigned long)m->addr + msize) <
347 curstart)
348 continue;
349 if ((unsigned long)m->addr > (curstart +
350 cursize))
351 break;
352 vmstart = (curstart < (unsigned long)m->addr ?
353 (unsigned long)m->addr : curstart);
354 if (((unsigned long)m->addr + msize) >
355 (curstart + cursize))
356 vmsize = curstart + cursize - vmstart;
357 else
358 vmsize = (unsigned long)m->addr +
359 msize - vmstart;
360 curstart = vmstart + vmsize;
361 cursize -= vmsize;
362 /* don't dump ioremap'd stuff! (TA) */
363 if (m->flags & VM_IOREMAP)
364 continue;
365 memcpy(elf_buf + (vmstart - start),
366 (char *)vmstart, vmsize);
367 }
368 read_unlock(&vmlist_lock);
369 if (copy_to_user(buffer, elf_buf, tsz)) {
370 kfree(elf_buf);
371 return -EFAULT;
372 }
373 kfree(elf_buf);
374 } else {
375 if (kern_addr_valid(start)) {
376 unsigned long n;
377
378 n = copy_to_user(buffer, (char *)start, tsz);
379 /*
380 * We cannot distingush between fault on source
381 * and fault on destination. When this happens
382 * we clear too and hope it will trigger the
383 * EFAULT again.
384 */
385 if (n) {
386 if (clear_user(buffer + tsz - n,
387 tsz - n))
388 return -EFAULT;
389 }
390 } else {
391 if (clear_user(buffer, tsz))
392 return -EFAULT;
393 }
394 }
395 buflen -= tsz;
396 *fpos += tsz;
397 buffer += tsz;
398 acc += tsz;
399 start += tsz;
400 tsz = (buflen > PAGE_SIZE ? PAGE_SIZE : buflen);
401 }
402
403 return acc;
404 }
405
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