LXR linux-old/fs/proc/kcore.c

   1/*
   2 *      fs/proc/kcore.c kernel ELF/AOUT 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 <asm/uaccess.h>
  22#include <asm/io.h>
  23
  24
  25static int open_kcore(struct inode * inode, struct file * filp)
  26{
  27        return capable(CAP_SYS_RAWIO) ? 0 : -EPERM;
  28}
  29
  30static loff_t lseek_kcore(struct file * file, loff_t offset, int origin);
  31
  32static ssize_t read_kcore(struct file *, char *, size_t, loff_t *);
  33
  34struct file_operations proc_kcore_operations = {
  35        read:           read_kcore,
  36        open:           open_kcore,
  37        llseek:         lseek_kcore,
  38};
  39
  40#ifdef CONFIG_KCORE_AOUT
  41static ssize_t read_kcore(struct file *file, char *buf, size_t count, loff_t *ppos)
  42{
  43        unsigned long long p = *ppos, memsize;
  44        ssize_t read;
  45        ssize_t count1;
  46        char * pnt;
  47        struct user dump;
  48#if defined (__i386__) || defined (__mc68000__) || defined(__x86_64__)
  49#       define FIRST_MAPPED     PAGE_SIZE       /* we don't have page 0 mapped on x86.. */
  50#else
  51#       define FIRST_MAPPED     0
  52#endif
  53
  54        memset(&dump, 0, sizeof(struct user));
  55        dump.magic = CMAGIC;
  56        dump.u_dsize = (virt_to_phys(high_memory) >> PAGE_SHIFT);
  57#if defined (__i386__) || defined(__x86_64__)
  58        dump.start_code = PAGE_OFFSET;
  59#endif
  60#ifdef __alpha__
  61        dump.start_data = PAGE_OFFSET;
  62#endif
  63
  64        memsize = virt_to_phys(high_memory);
  65        if (p >= memsize)
  66                return 0;
  67        if (count > memsize - p)
  68                count = memsize - p;
  69        read = 0;
  70
  71        if (p < sizeof(struct user) && count > 0) {
  72                count1 = count;
  73                if (p + count1 > sizeof(struct user))
  74                        count1 = sizeof(struct user)-p;
  75                pnt = (char *) &dump + p;
  76                if (copy_to_user(buf,(void *) pnt, count1))
  77                        return -EFAULT;
  78                buf += count1;
  79                p += count1;
  80                count -= count1;
  81                read += count1;
  82        }
  83
  84        if (count > 0 && p < PAGE_SIZE + FIRST_MAPPED) {
  85                count1 = PAGE_SIZE + FIRST_MAPPED - p;
  86                if (count1 > count)
  87                        count1 = count;
  88                if (clear_user(buf, count1))
  89                        return -EFAULT;
  90                buf += count1;
  91                p += count1;
  92                count -= count1;
  93                read += count1;
  94        }
  95        if (count > 0) {
  96                if (copy_to_user(buf, (void *) (PAGE_OFFSET+p-PAGE_SIZE), count))
  97                        return -EFAULT;
  98                read += count;
  99                p += count;
 100        }
 101        *ppos = p;
 102        return read;
 103}
 104#else /* CONFIG_KCORE_AOUT */
 105
 106#define roundup(x, y)  ((((x)+((y)-1))/(y))*(y))
 107
 108/* An ELF note in memory */
 109struct memelfnote
 110{
 111        const char *name;
 112        int type;
 113        unsigned int datasz;
 114        void *data;
 115};
 116
 117extern char saved_command_line[];
 118
 119static unsigned long get_kcore_size(int *num_vma, size_t *elf_buflen)
 120{
 121        unsigned long try, size;
 122        struct vm_struct *m;
 123
 124        *num_vma = 0;
 125        size = ((size_t)high_memory - PAGE_OFFSET + PAGE_SIZE);
 126        if (!vmlist) {
 127                *elf_buflen = PAGE_SIZE;
 128                return (size);
 129        }
 130
 131        for (m=vmlist; m; m=m->next) {
 132                try = (unsigned long)m->addr + m->size;
 133                if (try > size)
 134                        size = try;
 135                *num_vma = *num_vma + 1;
 136        }
 137        *elf_buflen =   sizeof(struct elfhdr) + 
 138                        (*num_vma + 2)*sizeof(struct elf_phdr) + 
 139                        3 * (sizeof(struct elf_note) + 4) +
 140                        sizeof(struct elf_prstatus) +
 141                        sizeof(struct elf_prpsinfo) +
 142                        sizeof(struct task_struct);
 143        *elf_buflen = PAGE_ALIGN(*elf_buflen);
 144        return (size - PAGE_OFFSET + *elf_buflen);
 145}
 146
 147
 148/*****************************************************************************/
 149/*
 150 * determine size of ELF note
 151 */
 152static int notesize(struct memelfnote *en)
 153{
 154        int sz;
 155
 156        sz = sizeof(struct elf_note);
 157        sz += roundup(strlen(en->name), 4);
 158        sz += roundup(en->datasz, 4);
 159
 160        return sz;
 161} /* end notesize() */
 162
 163/*****************************************************************************/
 164/*
 165 * store a note in the header buffer
 166 */
 167static char *storenote(struct memelfnote *men, char *bufp)
 168{
 169        struct elf_note en;
 170
 171#define DUMP_WRITE(addr,nr) do { memcpy(bufp,addr,nr); bufp += nr; } while(0)
 172
 173        en.n_namesz = strlen(men->name);
 174        en.n_descsz = men->datasz;
 175        en.n_type = men->type;
 176
 177        DUMP_WRITE(&en, sizeof(en));
 178        DUMP_WRITE(men->name, en.n_namesz);
 179
 180        /* XXX - cast from long long to long to avoid need for libgcc.a */
 181        bufp = (char*) roundup((unsigned long)bufp,4);
 182        DUMP_WRITE(men->data, men->datasz);
 183        bufp = (char*) roundup((unsigned long)bufp,4);
 184
 185#undef DUMP_WRITE
 186
 187        return bufp;
 188} /* end storenote() */
 189
 190/*
 191 * store an ELF coredump header in the supplied buffer
 192 * num_vma is the number of elements in vmlist
 193 */
 194static void elf_kcore_store_hdr(char *bufp, int num_vma, int dataoff)
 195{
 196        struct elf_prstatus prstatus;   /* NT_PRSTATUS */
 197        struct elf_prpsinfo prpsinfo;   /* NT_PRPSINFO */
 198        struct elf_phdr *nhdr, *phdr;
 199        struct elfhdr *elf;
 200        struct memelfnote notes[3];
 201        off_t offset = 0;
 202        struct vm_struct *m;
 203
 204        /* setup ELF header */
 205        elf = (struct elfhdr *) bufp;
 206        bufp += sizeof(struct elfhdr);
 207        offset += sizeof(struct elfhdr);
 208        memcpy(elf->e_ident, ELFMAG, SELFMAG);
 209        elf->e_ident[EI_CLASS]  = ELF_CLASS;
 210        elf->e_ident[EI_DATA]   = ELF_DATA;
 211        elf->e_ident[EI_VERSION]= EV_CURRENT;
 212        memset(elf->e_ident+EI_PAD, 0, EI_NIDENT-EI_PAD);
 213        elf->e_type     = ET_CORE;
 214        elf->e_machine  = ELF_ARCH;
 215        elf->e_version  = EV_CURRENT;
 216        elf->e_entry    = 0;
 217        elf->e_phoff    = sizeof(struct elfhdr);
 218        elf->e_shoff    = 0;
 219        elf->e_flags    = 0;
 220        elf->e_ehsize   = sizeof(struct elfhdr);
 221        elf->e_phentsize= sizeof(struct elf_phdr);
 222        elf->e_phnum    = 2 + num_vma;
 223        elf->e_shentsize= 0;
 224        elf->e_shnum    = 0;
 225        elf->e_shstrndx = 0;
 226
 227        /* setup ELF PT_NOTE program header */
 228        nhdr = (struct elf_phdr *) bufp;
 229        bufp += sizeof(struct elf_phdr);
 230        offset += sizeof(struct elf_phdr);
 231        nhdr->p_type    = PT_NOTE;
 232        nhdr->p_offset  = 0;
 233        nhdr->p_vaddr   = 0;
 234        nhdr->p_paddr   = 0;
 235        nhdr->p_filesz  = 0;
 236        nhdr->p_memsz   = 0;
 237        nhdr->p_flags   = 0;
 238        nhdr->p_align   = 0;
 239
 240        /* setup ELF PT_LOAD program header for the 
 241         * virtual range 0xc0000000 -> high_memory */
 242        phdr = (struct elf_phdr *) bufp;
 243        bufp += sizeof(struct elf_phdr);
 244        offset += sizeof(struct elf_phdr);
 245        phdr->p_type    = PT_LOAD;
 246        phdr->p_flags   = PF_R|PF_W|PF_X;
 247        phdr->p_offset  = dataoff;
 248        phdr->p_vaddr   = PAGE_OFFSET;
 249        phdr->p_paddr   = __pa(PAGE_OFFSET);
 250        phdr->p_filesz  = phdr->p_memsz = ((unsigned long)high_memory - PAGE_OFFSET);
 251        phdr->p_align   = PAGE_SIZE;
 252
 253        /* setup ELF PT_LOAD program header for every vmalloc'd area */
 254        for (m=vmlist; m; m=m->next) {
 255                if (m->flags & VM_IOREMAP) /* don't dump ioremap'd stuff! (TA) */
 256                        continue;
 257
 258                phdr = (struct elf_phdr *) bufp;
 259                bufp += sizeof(struct elf_phdr);
 260                offset += sizeof(struct elf_phdr);
 261
 262                phdr->p_type    = PT_LOAD;
 263                phdr->p_flags   = PF_R|PF_W|PF_X;
 264                phdr->p_offset  = (size_t)m->addr - PAGE_OFFSET + dataoff;
 265                phdr->p_vaddr   = (size_t)m->addr;
 266                phdr->p_paddr   = __pa(m->addr);
 267                phdr->p_filesz  = phdr->p_memsz = m->size;
 268                phdr->p_align   = PAGE_SIZE;
 269        }
 270
 271        /*
 272         * Set up the notes in similar form to SVR4 core dumps made
 273         * with info from their /proc.
 274         */
 275        nhdr->p_offset  = offset;
 276
 277        /* set up the process status */
 278        notes[0].name = "CORE";
 279        notes[0].type = NT_PRSTATUS;
 280        notes[0].datasz = sizeof(struct elf_prstatus);
 281        notes[0].data = &prstatus;
 282
 283        memset(&prstatus, 0, sizeof(struct elf_prstatus));
 284
 285        nhdr->p_filesz += notesize(&notes[0]);
 286        bufp = storenote(&notes[0], bufp);
 287
 288        /* set up the process info */
 289        notes[1].name   = "CORE";
 290        notes[1].type   = NT_PRPSINFO;
 291        notes[1].datasz = sizeof(struct elf_prpsinfo);
 292        notes[1].data   = &prpsinfo;
 293
 294        memset(&prpsinfo, 0, sizeof(struct elf_prpsinfo));
 295        prpsinfo.pr_state       = 0;
 296        prpsinfo.pr_sname       = 'R';
 297        prpsinfo.pr_zomb        = 0;
 298
 299        strcpy(prpsinfo.pr_fname, "vmlinux");
 300        strncpy(prpsinfo.pr_psargs, saved_command_line, ELF_PRARGSZ);
 301
 302        nhdr->p_filesz += notesize(&notes[1]);
 303        bufp = storenote(&notes[1], bufp);
 304
 305        /* set up the task structure */
 306        notes[2].name   = "CORE";
 307        notes[2].type   = NT_TASKSTRUCT;
 308        notes[2].datasz = sizeof(struct task_struct);
 309        notes[2].data   = current;
 310
 311        nhdr->p_filesz += notesize(&notes[2]);
 312        bufp = storenote(&notes[2], bufp);
 313
 314} /* end elf_kcore_store_hdr() */
 315
 316/*****************************************************************************/
 317/*
 318 * read from the ELF header and then kernel memory
 319 */
 320static ssize_t read_kcore(struct file *file, char *buffer, size_t buflen, loff_t *fpos)
 321{
 322        ssize_t acc = 0;
 323        unsigned long size, tsz;
 324        size_t elf_buflen;
 325        int num_vma;
 326        unsigned long start;
 327
 328        read_lock(&vmlist_lock);
 329        proc_root_kcore->size = size = get_kcore_size(&num_vma, &elf_buflen);
 330        if (buflen == 0 || (unsigned long long)*fpos >= size) {
 331                read_unlock(&vmlist_lock);
 332                return 0;
 333        }
 334
 335        /* trim buflen to not go beyond EOF */
 336        if (buflen > size - *fpos)
 337                buflen = size - *fpos;
 338
 339        /* construct an ELF core header if we'll need some of it */
 340        if (*fpos < elf_buflen) {
 341                char * elf_buf;
 342
 343                tsz = elf_buflen - *fpos;
 344                if (buflen < tsz)
 345                        tsz = buflen;
 346                elf_buf = kmalloc(elf_buflen, GFP_ATOMIC);
 347                if (!elf_buf) {
 348                        read_unlock(&vmlist_lock);
 349                        return -ENOMEM;
 350                }
 351                memset(elf_buf, 0, elf_buflen);
 352                elf_kcore_store_hdr(elf_buf, num_vma, elf_buflen);
 353                read_unlock(&vmlist_lock);
 354                if (copy_to_user(buffer, elf_buf + *fpos, tsz)) {
 355                        kfree(elf_buf);
 356                        return -EFAULT;
 357                }
 358                kfree(elf_buf);
 359                buflen -= tsz;
 360                *fpos += tsz;
 361                buffer += tsz;
 362                acc += tsz;
 363
 364                /* leave now if filled buffer already */
 365                if (buflen == 0)
 366                        return acc;
 367        } else
 368                read_unlock(&vmlist_lock);
 369
 370        /* where page 0 not mapped, write zeros into buffer */
 371#if defined (__i386__) || defined (__mc68000__) || defined(__x86_64__)
 372        if (*fpos < PAGE_SIZE + elf_buflen) {
 373                /* work out how much to clear */
 374                tsz = PAGE_SIZE + elf_buflen - *fpos;
 375                if (buflen < tsz)
 376                        tsz = buflen;
 377
 378                /* write zeros to buffer */
 379                if (clear_user(buffer, tsz))
 380                        return -EFAULT;
 381                buflen -= tsz;
 382                *fpos += tsz;
 383                buffer += tsz;
 384                acc += tsz;
 385
 386                /* leave now if filled buffer already */
 387                if (buflen == 0)
 388                        return tsz;
 389        }
 390#endif
 391        
 392        /*
 393         * Fill the remainder of the buffer from kernel VM space.
 394         * We said in the ELF header that the data which starts
 395         * at 'elf_buflen' is virtual address PAGE_OFFSET. --rmk
 396         */
 397        start = PAGE_OFFSET + (*fpos - elf_buflen);
 398        if ((tsz = (PAGE_SIZE - (start & ~PAGE_MASK))) > buflen)
 399                tsz = buflen;
 400        while (buflen) {
 401                int err; 
 402        
 403                if ((start > PAGE_OFFSET) && (start < (unsigned long)high_memory)) {
 404                        if (kern_addr_valid(start)) {
 405                                err = copy_to_user(buffer, (char *)start, tsz);
 406                        } else {
 407                                err = clear_user(buffer, tsz);
 408                        }
 409                } else {
 410                        char * elf_buf;
 411                        struct vm_struct *m;
 412                        unsigned long curstart = start;
 413                        unsigned long cursize = tsz;
 414
 415                        elf_buf = kmalloc(tsz, GFP_KERNEL);
 416                        if (!elf_buf)
 417                                return -ENOMEM;
 418                        memset(elf_buf, 0, tsz);
 419
 420                        read_lock(&vmlist_lock);
 421                        for (m=vmlist; m && cursize; m=m->next) {
 422                                unsigned long vmstart;
 423                                unsigned long vmsize;
 424                                unsigned long msize = m->size - PAGE_SIZE;
 425
 426                                if (((unsigned long)m->addr + msize) < 
 427                                                                curstart)
 428                                        continue;
 429                                if ((unsigned long)m->addr > (curstart + 
 430                                                                cursize))
 431                                        break;
 432                                vmstart = (curstart < (unsigned long)m->addr ? 
 433                                        (unsigned long)m->addr : curstart);
 434                                if (((unsigned long)m->addr + msize) > 
 435                                                        (curstart + cursize))
 436                                        vmsize = curstart + cursize - vmstart;
 437                                else
 438                                        vmsize = (unsigned long)m->addr + 
 439                                                        msize - vmstart;
 440                                curstart = vmstart + vmsize;
 441                                cursize -= vmsize;
 442                                /* don't dump ioremap'd stuff! (TA) */
 443                                if (m->flags & VM_IOREMAP)
 444                                        continue;
 445                                memcpy(elf_buf + (vmstart - start),
 446                                        (char *)vmstart, vmsize);
 447                        }
 448                        read_unlock(&vmlist_lock);
 449                        err = copy_to_user(buffer, elf_buf, tsz); 
 450                                kfree(elf_buf);
 451                        }
 452                if (err)
 453                                        return -EFAULT;
 454                buflen -= tsz;
 455                *fpos += tsz;
 456                buffer += tsz;
 457                acc += tsz;
 458                start += tsz;
 459                tsz = (buflen > PAGE_SIZE ? PAGE_SIZE : buflen);
 460        }
 461
 462        return acc;
 463}
 464#endif /* CONFIG_KCORE_AOUT */
 465
 466static loff_t lseek_kcore(struct file * file, loff_t offset, int origin)
 467{
 468        switch (origin) {
 469                case 2:
 470                        offset += file->f_dentry->d_inode->i_size;
 471                        break;
 472                case 1:
 473                        offset += file->f_pos;
 474        }
 475        /* RED-PEN user can fake an error here by setting offset to >=-4095 && <0  */
 476        file->f_pos = offset;
 477        return offset;
 478}
 479