Merge master.kernel.org:/home/rmk/linux-2.6-arm
[linux-2.6] / fs / proc / kcore.c
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/capability.h>
18 #include <linux/elf.h>
19 #include <linux/elfcore.h>
20 #include <linux/vmalloc.h>
21 #include <linux/highmem.h>
22 #include <linux/init.h>
23 #include <asm/uaccess.h>
24 #include <asm/io.h>
25
26
27 static int open_kcore(struct inode * inode, struct file * filp)
28 {
29         return capable(CAP_SYS_RAWIO) ? 0 : -EPERM;
30 }
31
32 static ssize_t read_kcore(struct file *, char __user *, size_t, loff_t *);
33
34 const struct file_operations proc_kcore_operations = {
35         .read           = read_kcore,
36         .open           = open_kcore,
37 };
38
39 #ifndef kc_vaddr_to_offset
40 #define kc_vaddr_to_offset(v) ((v) - PAGE_OFFSET)
41 #endif
42 #ifndef kc_offset_to_vaddr
43 #define kc_offset_to_vaddr(o) ((o) + PAGE_OFFSET)
44 #endif
45
46 #define roundup(x, y)  ((((x)+((y)-1))/(y))*(y))
47
48 /* An ELF note in memory */
49 struct memelfnote
50 {
51         const char *name;
52         int type;
53         unsigned int datasz;
54         void *data;
55 };
56
57 static struct kcore_list *kclist;
58 static DEFINE_RWLOCK(kclist_lock);
59
60 void
61 kclist_add(struct kcore_list *new, void *addr, size_t size)
62 {
63         new->addr = (unsigned long)addr;
64         new->size = size;
65
66         write_lock(&kclist_lock);
67         new->next = kclist;
68         kclist = new;
69         write_unlock(&kclist_lock);
70 }
71
72 static size_t get_kcore_size(int *nphdr, size_t *elf_buflen)
73 {
74         size_t try, size;
75         struct kcore_list *m;
76
77         *nphdr = 1; /* PT_NOTE */
78         size = 0;
79
80         for (m=kclist; m; m=m->next) {
81                 try = kc_vaddr_to_offset((size_t)m->addr + m->size);
82                 if (try > size)
83                         size = try;
84                 *nphdr = *nphdr + 1;
85         }
86         *elf_buflen =   sizeof(struct elfhdr) + 
87                         (*nphdr + 2)*sizeof(struct elf_phdr) + 
88                         3 * (sizeof(struct elf_note) + 4) +
89                         sizeof(struct elf_prstatus) +
90                         sizeof(struct elf_prpsinfo) +
91                         sizeof(struct task_struct);
92         *elf_buflen = PAGE_ALIGN(*elf_buflen);
93         return size + *elf_buflen;
94 }
95
96
97 /*****************************************************************************/
98 /*
99  * determine size of ELF note
100  */
101 static int notesize(struct memelfnote *en)
102 {
103         int sz;
104
105         sz = sizeof(struct elf_note);
106         sz += roundup(strlen(en->name), 4);
107         sz += roundup(en->datasz, 4);
108
109         return sz;
110 } /* end notesize() */
111
112 /*****************************************************************************/
113 /*
114  * store a note in the header buffer
115  */
116 static char *storenote(struct memelfnote *men, char *bufp)
117 {
118         struct elf_note en;
119
120 #define DUMP_WRITE(addr,nr) do { memcpy(bufp,addr,nr); bufp += nr; } while(0)
121
122         en.n_namesz = strlen(men->name);
123         en.n_descsz = men->datasz;
124         en.n_type = men->type;
125
126         DUMP_WRITE(&en, sizeof(en));
127         DUMP_WRITE(men->name, en.n_namesz);
128
129         /* XXX - cast from long long to long to avoid need for libgcc.a */
130         bufp = (char*) roundup((unsigned long)bufp,4);
131         DUMP_WRITE(men->data, men->datasz);
132         bufp = (char*) roundup((unsigned long)bufp,4);
133
134 #undef DUMP_WRITE
135
136         return bufp;
137 } /* end storenote() */
138
139 /*
140  * store an ELF coredump header in the supplied buffer
141  * nphdr is the number of elf_phdr to insert
142  */
143 static void elf_kcore_store_hdr(char *bufp, int nphdr, int dataoff)
144 {
145         struct elf_prstatus prstatus;   /* NT_PRSTATUS */
146         struct elf_prpsinfo prpsinfo;   /* NT_PRPSINFO */
147         struct elf_phdr *nhdr, *phdr;
148         struct elfhdr *elf;
149         struct memelfnote notes[3];
150         off_t offset = 0;
151         struct kcore_list *m;
152
153         /* setup ELF header */
154         elf = (struct elfhdr *) bufp;
155         bufp += sizeof(struct elfhdr);
156         offset += sizeof(struct elfhdr);
157         memcpy(elf->e_ident, ELFMAG, SELFMAG);
158         elf->e_ident[EI_CLASS]  = ELF_CLASS;
159         elf->e_ident[EI_DATA]   = ELF_DATA;
160         elf->e_ident[EI_VERSION]= EV_CURRENT;
161         elf->e_ident[EI_OSABI] = ELF_OSABI;
162         memset(elf->e_ident+EI_PAD, 0, EI_NIDENT-EI_PAD);
163         elf->e_type     = ET_CORE;
164         elf->e_machine  = ELF_ARCH;
165         elf->e_version  = EV_CURRENT;
166         elf->e_entry    = 0;
167         elf->e_phoff    = sizeof(struct elfhdr);
168         elf->e_shoff    = 0;
169 #if defined(CONFIG_H8300)
170         elf->e_flags    = ELF_FLAGS;
171 #else
172         elf->e_flags    = 0;
173 #endif
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";
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";
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";
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 = kmalloc(elf_buflen, GFP_ATOMIC);
286                 if (!elf_buf) {
287                         read_unlock(&kclist_lock);
288                         return -ENOMEM;
289                 }
290                 memset(elf_buf, 0, elf_buflen);
291                 elf_kcore_store_hdr(elf_buf, nphdr, elf_buflen);
292                 read_unlock(&kclist_lock);
293                 if (copy_to_user(buffer, elf_buf + *fpos, tsz)) {
294                         kfree(elf_buf);
295                         return -EFAULT;
296                 }
297                 kfree(elf_buf);
298                 buflen -= tsz;
299                 *fpos += tsz;
300                 buffer += tsz;
301                 acc += tsz;
302
303                 /* leave now if filled buffer already */
304                 if (buflen == 0)
305                         return acc;
306         } else
307                 read_unlock(&kclist_lock);
308
309         /*
310          * Check to see if our file offset matches with any of
311          * the addresses in the elf_phdr on our list.
312          */
313         start = kc_offset_to_vaddr(*fpos - elf_buflen);
314         if ((tsz = (PAGE_SIZE - (start & ~PAGE_MASK))) > buflen)
315                 tsz = buflen;
316                 
317         while (buflen) {
318                 struct kcore_list *m;
319
320                 read_lock(&kclist_lock);
321                 for (m=kclist; m; m=m->next) {
322                         if (start >= m->addr && start < (m->addr+m->size))
323                                 break;
324                 }
325                 read_unlock(&kclist_lock);
326
327                 if (m == NULL) {
328                         if (clear_user(buffer, tsz))
329                                 return -EFAULT;
330                 } else if ((start >= VMALLOC_START) && (start < VMALLOC_END)) {
331                         char * elf_buf;
332                         struct vm_struct *m;
333                         unsigned long curstart = start;
334                         unsigned long cursize = tsz;
335
336                         elf_buf = kmalloc(tsz, GFP_KERNEL);
337                         if (!elf_buf)
338                                 return -ENOMEM;
339                         memset(elf_buf, 0, tsz);
340
341                         read_lock(&vmlist_lock);
342                         for (m=vmlist; m && cursize; m=m->next) {
343                                 unsigned long vmstart;
344                                 unsigned long vmsize;
345                                 unsigned long msize = m->size - PAGE_SIZE;
346
347                                 if (((unsigned long)m->addr + msize) < 
348                                                                 curstart)
349                                         continue;
350                                 if ((unsigned long)m->addr > (curstart + 
351                                                                 cursize))
352                                         break;
353                                 vmstart = (curstart < (unsigned long)m->addr ? 
354                                         (unsigned long)m->addr : curstart);
355                                 if (((unsigned long)m->addr + msize) > 
356                                                         (curstart + cursize))
357                                         vmsize = curstart + cursize - vmstart;
358                                 else
359                                         vmsize = (unsigned long)m->addr + 
360                                                         msize - vmstart;
361                                 curstart = vmstart + vmsize;
362                                 cursize -= vmsize;
363                                 /* don't dump ioremap'd stuff! (TA) */
364                                 if (m->flags & VM_IOREMAP)
365                                         continue;
366                                 memcpy(elf_buf + (vmstart - start),
367                                         (char *)vmstart, vmsize);
368                         }
369                         read_unlock(&vmlist_lock);
370                         if (copy_to_user(buffer, elf_buf, tsz)) {
371                                 kfree(elf_buf);
372                                 return -EFAULT;
373                         }
374                         kfree(elf_buf);
375                 } else {
376                         if (kern_addr_valid(start)) {
377                                 unsigned long n;
378
379                                 n = copy_to_user(buffer, (char *)start, tsz);
380                                 /*
381                                  * We cannot distingush between fault on source
382                                  * and fault on destination. When this happens
383                                  * we clear too and hope it will trigger the
384                                  * EFAULT again.
385                                  */
386                                 if (n) { 
387                                         if (clear_user(buffer + tsz - n,
388                                                                 tsz - n))
389                                                 return -EFAULT;
390                                 }
391                         } else {
392                                 if (clear_user(buffer, tsz))
393                                         return -EFAULT;
394                         }
395                 }
396                 buflen -= tsz;
397                 *fpos += tsz;
398                 buffer += tsz;
399                 acc += tsz;
400                 start += tsz;
401                 tsz = (buflen > PAGE_SIZE ? PAGE_SIZE : buflen);
402         }
403
404         return acc;
405 }