fs/binfmt_flat.c

   1 /****************************************************************************/
   2 /*
   3  *  linux/fs/binfmt_flat.c
   4  *
   5  *      Copyright (C) 2000-2003 David McCullough <davidm@snapgear.com>
   6  *      Copyright (C) 2002 Greg Ungerer <gerg@snapgear.com>
   7  *      Copyright (C) 2002 SnapGear, by Paul Dale <pauli@snapgear.com>
   8  *      Copyright (C) 2000, 2001 Lineo, by David McCullough <davidm@lineo.com>
   9  *  based heavily on:
  10  *
  11  *  linux/fs/binfmt_aout.c:
  12  *      Copyright (C) 1991, 1992, 1996  Linus Torvalds
  13  *  linux/fs/binfmt_flat.c for 2.0 kernel
  14  *          Copyright (C) 1998  Kenneth Albanowski <kjahds@kjahds.com>
  15  *      JAN/99 -- coded full program relocation (gerg@snapgear.com)
  16  */
  17
  18 #include <linux/export.h>
  19 #include <linux/kernel.h>
  20 #include <linux/sched.h>
  21 #include <linux/mm.h>
  22 #include <linux/mman.h>
  23 #include <linux/errno.h>
  24 #include <linux/signal.h>
  25 #include <linux/string.h>
  26 #include <linux/fs.h>
  27 #include <linux/file.h>
  28 #include <linux/stat.h>
  29 #include <linux/fcntl.h>
  30 #include <linux/ptrace.h>
  31 #include <linux/user.h>
  32 #include <linux/slab.h>
  33 #include <linux/binfmts.h>
  34 #include <linux/personality.h>
  35 #include <linux/init.h>
  36 #include <linux/flat.h>
  37 #include <linux/syscalls.h>
  38
  39 #include <asm/byteorder.h>
  40 #include <asm/uaccess.h>
  41 #include <asm/unaligned.h>
  42 #include <asm/cacheflush.h>
  43 #include <asm/page.h>
  44
  45 /****************************************************************************/
  46
  47 #if 0
  48 #define DEBUG 1
  49 #endif
  50
  51 #ifdef DEBUG
  52 #define DBG_FLT(a...)   printk(a)
  53 #else
  54 #define DBG_FLT(a...)
  55 #endif
  56
  57 /*
  58  * User data (data section and bss) needs to be aligned.
  59  * We pick 0x20 here because it is the max value elf2flt has always
  60  * used in producing FLAT files, and because it seems to be large
  61  * enough to make all the gcc alignment related tests happy.
  62  */
  63 #define FLAT_DATA_ALIGN (0x20)
  64
  65 /*
  66  * User data (stack) also needs to be aligned.
  67  * Here we can be a bit looser than the data sections since this
  68  * needs to only meet arch ABI requirements.
  69  */
  70 #define FLAT_STACK_ALIGN        max_t(unsigned long, sizeof(void *), ARCH_SLAB_MINALIGN)
  71
  72 #define RELOC_FAILED 0xff00ff01         /* Relocation incorrect somewhere */
  73 #define UNLOADED_LIB 0x7ff000ff         /* Placeholder for unused library */
  74
  75 struct lib_info {
  76         struct {
  77                 unsigned long start_code;               /* Start of text segment */
  78                 unsigned long start_data;               /* Start of data segment */
  79                 unsigned long start_brk;                /* End of data segment */
  80                 unsigned long text_len;                 /* Length of text segment */
  81                 unsigned long entry;                    /* Start address for this module */
  82                 unsigned long build_date;               /* When this one was compiled */
  83                 short loaded;                           /* Has this library been loaded? */
  84         } lib_list[MAX_SHARED_LIBS];
  85 };
  86
  87 #ifdef CONFIG_BINFMT_SHARED_FLAT
  88 static int load_flat_shared_library(int id, struct lib_info *p);
  89 #endif
  90
  91 static int load_flat_binary(struct linux_binprm *, struct pt_regs * regs);
  92 static int flat_core_dump(struct coredump_params *cprm);
  93
  94 static struct linux_binfmt flat_format = {
  95         .module         = THIS_MODULE,
  96         .load_binary    = load_flat_binary,
  97         .core_dump      = flat_core_dump,
  98         .min_coredump   = PAGE_SIZE
  99 };
 100
 101 /****************************************************************************/
 102 /*
 103  * Routine writes a core dump image in the current directory.
 104  * Currently only a stub-function.
 105  */
 106
 107 static int flat_core_dump(struct coredump_params *cprm)
 108 {
 109         printk("Process %s:%d received signr %d and should have core dumped\n",
 110                         current->comm, current->pid, (int) cprm->signr);
 111         return(1);
 112 }
 113
 114 /****************************************************************************/
 115 /*
 116  * create_flat_tables() parses the env- and arg-strings in new user
 117  * memory and creates the pointer tables from them, and puts their
 118  * addresses on the "stack", returning the new stack pointer value.
 119  */
 120
 121 static unsigned long create_flat_tables(
 122         unsigned long pp,
 123         struct linux_binprm * bprm)
 124 {
 125         unsigned long *argv,*envp;
 126         unsigned long * sp;
 127         char * p = (char*)pp;
 128         int argc = bprm->argc;
 129         int envc = bprm->envc;
 130         char uninitialized_var(dummy);
 131
 132         sp = (unsigned long *)p;
 133         sp -= (envc + argc + 2) + 1 + (flat_argvp_envp_on_stack() ? 2 : 0);
 134         sp = (unsigned long *) ((unsigned long)sp & -FLAT_STACK_ALIGN);
 135         argv = sp + 1 + (flat_argvp_envp_on_stack() ? 2 : 0);
 136         envp = argv + (argc + 1);
 137
 138         if (flat_argvp_envp_on_stack()) {
 139                 put_user((unsigned long) envp, sp + 2);
 140                 put_user((unsigned long) argv, sp + 1);
 141         }
 142
 143         put_user(argc, sp);
 144         current->mm->arg_start = (unsigned long) p;
 145         while (argc-->0) {
 146                 put_user((unsigned long) p, argv++);
 147                 do {
 148                         get_user(dummy, p); p++;
 149                 } while (dummy);
 150         }
 151         put_user((unsigned long) NULL, argv);
 152         current->mm->arg_end = current->mm->env_start = (unsigned long) p;
 153         while (envc-->0) {
 154                 put_user((unsigned long)p, envp); envp++;
 155                 do {
 156                         get_user(dummy, p); p++;
 157                 } while (dummy);
 158         }
 159         put_user((unsigned long) NULL, envp);
 160         current->mm->env_end = (unsigned long) p;
 161         return (unsigned long)sp;
 162 }
 163
 164 /****************************************************************************/
 165
 166 #ifdef CONFIG_BINFMT_ZFLAT
 167
 168 #include <linux/zlib.h>
 169
 170 #define LBUFSIZE        4000
 171
 172 /* gzip flag byte */
 173 #define ASCII_FLAG   0x01 /* bit 0 set: file probably ASCII text */
 174 #define CONTINUATION 0x02 /* bit 1 set: continuation of multi-part gzip file */
 175 #define EXTRA_FIELD  0x04 /* bit 2 set: extra field present */
 176 #define ORIG_NAME    0x08 /* bit 3 set: original file name present */
 177 #define COMMENT      0x10 /* bit 4 set: file comment present */
 178 #define ENCRYPTED    0x20 /* bit 5 set: file is encrypted */
 179 #define RESERVED     0xC0 /* bit 6,7:   reserved */
 180
 181 static int decompress_exec(
 182         struct linux_binprm *bprm,
 183         unsigned long offset,
 184         char *dst,
 185         long len,
 186         int fd)
 187 {
 188         unsigned char *buf;
 189         z_stream strm;
 190         loff_t fpos;
 191         int ret, retval;
 192
 193         DBG_FLT("decompress_exec(offset=%x,buf=%x,len=%x)\n",(int)offset, (int)dst, (int)len);
 194
 195         memset(&strm, 0, sizeof(strm));
 196         strm.workspace = kmalloc(zlib_inflate_workspacesize(), GFP_KERNEL);
 197         if (strm.workspace == NULL) {
 198                 DBG_FLT("binfmt_flat: no memory for decompress workspace\n");
 199                 return -ENOMEM;
 200         }
 201         buf = kmalloc(LBUFSIZE, GFP_KERNEL);
 202         if (buf == NULL) {
 203                 DBG_FLT("binfmt_flat: no memory for read buffer\n");
 204                 retval = -ENOMEM;
 205                 goto out_free;
 206         }
 207
 208         /* Read in first chunk of data and parse gzip header. */
 209         fpos = offset;
 210         ret = bprm->file->f_op->read(bprm->file, buf, LBUFSIZE, &fpos);
 211
 212         strm.next_in = buf;
 213         strm.avail_in = ret;
 214         strm.total_in = 0;
 215
 216         retval = -ENOEXEC;
 217
 218         /* Check minimum size -- gzip header */
 219         if (ret < 10) {
 220                 DBG_FLT("binfmt_flat: file too small?\n");
 221                 goto out_free_buf;
 222         }
 223
 224         /* Check gzip magic number */
 225         if ((buf[0] != 037) || ((buf[1] != 0213) && (buf[1] != 0236))) {
 226                 DBG_FLT("binfmt_flat: unknown compression magic?\n");
 227                 goto out_free_buf;
 228         }
 229
 230         /* Check gzip method */
 231         if (buf[2] != 8) {
 232                 DBG_FLT("binfmt_flat: unknown compression method?\n");
 233                 goto out_free_buf;
 234         }
 235         /* Check gzip flags */
 236         if ((buf[3] & ENCRYPTED) || (buf[3] & CONTINUATION) ||
 237             (buf[3] & RESERVED)) {
 238                 DBG_FLT("binfmt_flat: unknown flags?\n");
 239                 goto out_free_buf;
 240         }
 241
 242         ret = 10;
 243         if (buf[3] & EXTRA_FIELD) {
 244                 ret += 2 + buf[10] + (buf[11] << 8);
 245                 if (unlikely(LBUFSIZE <= ret)) {
 246                         DBG_FLT("binfmt_flat: buffer overflow (EXTRA)?\n");
 247                         goto out_free_buf;
 248                 }
 249         }
 250         if (buf[3] & ORIG_NAME) {
 251                 while (ret < LBUFSIZE && buf[ret++] != 0)
 252                         ;
 253                 if (unlikely(LBUFSIZE == ret)) {
 254                         DBG_FLT("binfmt_flat: buffer overflow (ORIG_NAME)?\n");
 255                         goto out_free_buf;
 256                 }
 257         }
 258         if (buf[3] & COMMENT) {
 259                 while (ret < LBUFSIZE && buf[ret++] != 0)
 260                         ;
 261                 if (unlikely(LBUFSIZE == ret)) {
 262                         DBG_FLT("binfmt_flat: buffer overflow (COMMENT)?\n");
 263                         goto out_free_buf;
 264                 }
 265         }
 266
 267         strm.next_in += ret;
 268         strm.avail_in -= ret;
 269
 270         strm.next_out = dst;
 271         strm.avail_out = len;
 272         strm.total_out = 0;
 273
 274         if (zlib_inflateInit2(&strm, -MAX_WBITS) != Z_OK) {
 275                 DBG_FLT("binfmt_flat: zlib init failed?\n");
 276                 goto out_free_buf;
 277         }
 278
 279         while ((ret = zlib_inflate(&strm, Z_NO_FLUSH)) == Z_OK) {
 280                 ret = bprm->file->f_op->read(bprm->file, buf, LBUFSIZE, &fpos);
 281                 if (ret <= 0)
 282                         break;
 283                 len -= ret;
 284
 285                 strm.next_in = buf;
 286                 strm.avail_in = ret;
 287                 strm.total_in = 0;
 288         }
 289
 290         if (ret < 0) {
 291                 DBG_FLT("binfmt_flat: decompression failed (%d), %s\n",
 292                         ret, strm.msg);
 293                 goto out_zlib;
 294         }
 295
 296         retval = 0;
 297 out_zlib:
 298         zlib_inflateEnd(&strm);
 299 out_free_buf:
 300         kfree(buf);
 301 out_free:
 302         kfree(strm.workspace);
 303         return retval;
 304 }
 305
 306 #endif /* CONFIG_BINFMT_ZFLAT */
 307
 308 /****************************************************************************/
 309
 310 static unsigned long
 311 calc_reloc(unsigned long r, struct lib_info *p, int curid, int internalp)
 312 {
 313         unsigned long addr;
 314         int id;
 315         unsigned long start_brk;
 316         unsigned long start_data;
 317         unsigned long text_len;
 318         unsigned long start_code;
 319
 320 #ifdef CONFIG_BINFMT_SHARED_FLAT
 321         if (r == 0)
 322                 id = curid;     /* Relocs of 0 are always self referring */
 323         else {
 324                 id = (r >> 24) & 0xff;  /* Find ID for this reloc */
 325                 r &= 0x00ffffff;        /* Trim ID off here */
 326         }
 327         if (id >= MAX_SHARED_LIBS) {
 328                 printk("BINFMT_FLAT: reference 0x%x to shared library %d",
 329                                 (unsigned) r, id);
 330                 goto failed;
 331         }
 332         if (curid != id) {
 333                 if (internalp) {
 334                         printk("BINFMT_FLAT: reloc address 0x%x not in same module "
 335                                         "(%d != %d)", (unsigned) r, curid, id);
 336                         goto failed;
 337                 } else if ( ! p->lib_list[id].loaded &&
 338                                 IS_ERR_VALUE(load_flat_shared_library(id, p))) {
 339                         printk("BINFMT_FLAT: failed to load library %d", id);
 340                         goto failed;
 341                 }
 342                 /* Check versioning information (i.e. time stamps) */
 343                 if (p->lib_list[id].build_date && p->lib_list[curid].build_date &&
 344                                 p->lib_list[curid].build_date < p->lib_list[id].build_date) {
 345                         printk("BINFMT_FLAT: library %d is younger than %d", id, curid);
 346                         goto failed;
 347                 }
 348         }
 349 #else
 350         id = 0;
 351 #endif
 352
 353         start_brk = p->lib_list[id].start_brk;
 354         start_data = p->lib_list[id].start_data;
 355         start_code = p->lib_list[id].start_code;
 356         text_len = p->lib_list[id].text_len;
 357
 358         if (!flat_reloc_valid(r, start_brk - start_data + text_len)) {
 359                 printk("BINFMT_FLAT: reloc outside program 0x%x (0 - 0x%x/0x%x)",
 360                        (int) r,(int)(start_brk-start_data+text_len),(int)text_len);
 361                 goto failed;
 362         }
 363
 364         if (r < text_len)                       /* In text segment */
 365                 addr = r + start_code;
 366         else                                    /* In data segment */
 367                 addr = r - text_len + start_data;
 368
 369         /* Range checked already above so doing the range tests is redundant...*/
 370         return(addr);
 371
 372 failed:
 373         printk(", killing %s!\n", current->comm);
 374         send_sig(SIGSEGV, current, 0);
 375
 376         return RELOC_FAILED;
 377 }
 378
 379 /****************************************************************************/
 380
 381 void old_reloc(unsigned long rl)
 382 {
 383 #ifdef DEBUG
 384         char *segment[] = { "TEXT", "DATA", "BSS", "*UNKNOWN*" };
 385 #endif
 386         flat_v2_reloc_t r;
 387         unsigned long *ptr;
 388
 389         r.value = rl;
 390 #if defined(CONFIG_COLDFIRE)
 391         ptr = (unsigned long *) (current->mm->start_code + r.reloc.offset);
 392 #else
 393         ptr = (unsigned long *) (current->mm->start_data + r.reloc.offset);
 394 #endif
 395
 396 #ifdef DEBUG
 397         printk("Relocation of variable at DATASEG+%x "
 398                 "(address %p, currently %x) into segment %s\n",
 399                 r.reloc.offset, ptr, (int)*ptr, segment[r.reloc.type]);
 400 #endif
 401
 402         switch (r.reloc.type) {
 403         case OLD_FLAT_RELOC_TYPE_TEXT:
 404                 *ptr += current->mm->start_code;
 405                 break;
 406         case OLD_FLAT_RELOC_TYPE_DATA:
 407                 *ptr += current->mm->start_data;
 408                 break;
 409         case OLD_FLAT_RELOC_TYPE_BSS:
 410                 *ptr += current->mm->end_data;
 411                 break;
 412         default:
 413                 printk("BINFMT_FLAT: Unknown relocation type=%x\n", r.reloc.type);
 414                 break;
 415         }
 416
 417 #ifdef DEBUG
 418         printk("Relocation became %x\n", (int)*ptr);
 419 #endif
 420 }
 421
 422 /****************************************************************************/
 423
 424 static int load_flat_file(struct linux_binprm * bprm,
 425                 struct lib_info *libinfo, int id, unsigned long *extra_stack)
 426 {
 427         struct flat_hdr * hdr;
 428         unsigned long textpos = 0, datapos = 0, result;
 429         unsigned long realdatastart = 0;
 430         unsigned long text_len, data_len, bss_len, stack_len, flags;
 431         unsigned long len, memp = 0;
 432         unsigned long memp_size, extra, rlim;
 433         unsigned long *reloc = 0, *rp;
 434         struct inode *inode;
 435         int i, rev, relocs = 0;
 436         loff_t fpos;
 437         unsigned long start_code, end_code;
 438         int ret;
 439
 440         hdr = ((struct flat_hdr *) bprm->buf);          /* exec-header */
 441         inode = bprm->file->f_path.dentry->d_inode;
 442
 443         text_len  = ntohl(hdr->data_start);
 444         data_len  = ntohl(hdr->data_end) - ntohl(hdr->data_start);
 445         bss_len   = ntohl(hdr->bss_end) - ntohl(hdr->data_end);
 446         stack_len = ntohl(hdr->stack_size);
 447         if (extra_stack) {
 448                 stack_len += *extra_stack;
 449                 *extra_stack = stack_len;
 450         }
 451         relocs    = ntohl(hdr->reloc_count);
 452         flags     = ntohl(hdr->flags);
 453         rev       = ntohl(hdr->rev);
 454
 455         if (strncmp(hdr->magic, "bFLT", 4)) {
 456                 /*
 457                  * Previously, here was a printk to tell people
 458                  *   "BINFMT_FLAT: bad header magic".
 459                  * But for the kernel which also use ELF FD-PIC format, this
 460                  * error message is confusing.
 461                  * because a lot of people do not manage to produce good
 462                  */
 463                 ret = -ENOEXEC;
 464                 goto err;
 465         }
 466
 467         if (flags & FLAT_FLAG_KTRACE)
 468                 printk("BINFMT_FLAT: Loading file: %s\n", bprm->filename);
 469
 470         if (rev != FLAT_VERSION && rev != OLD_FLAT_VERSION) {
 471                 printk("BINFMT_FLAT: bad flat file version 0x%x (supported "
 472                         "0x%lx and 0x%lx)\n",
 473                         rev, FLAT_VERSION, OLD_FLAT_VERSION);
 474                 ret = -ENOEXEC;
 475                 goto err;
 476         }
 477
 478         /* Don't allow old format executables to use shared libraries */
 479         if (rev == OLD_FLAT_VERSION && id != 0) {
 480                 printk("BINFMT_FLAT: shared libraries are not available before rev 0x%x\n",
 481                                 (int) FLAT_VERSION);
 482                 ret = -ENOEXEC;
 483                 goto err;
 484         }
 485
 486         /*
 487          * fix up the flags for the older format,  there were all kinds
 488          * of endian hacks,  this only works for the simple cases
 489          */
 490         if (rev == OLD_FLAT_VERSION && flat_old_ram_flag(flags))
 491                 flags = FLAT_FLAG_RAM;
 492
 493 #ifndef CONFIG_BINFMT_ZFLAT
 494         if (flags & (FLAT_FLAG_GZIP|FLAT_FLAG_GZDATA)) {
 495                 printk("Support for ZFLAT executables is not enabled.\n");
 496                 ret = -ENOEXEC;
 497                 goto err;
 498         }
 499 #endif
 500
 501         /*
 502          * Check initial limits. This avoids letting people circumvent
 503          * size limits imposed on them by creating programs with large
 504          * arrays in the data or bss.
 505          */
 506         rlim = rlimit(RLIMIT_DATA);
 507         if (rlim >= RLIM_INFINITY)
 508                 rlim = ~0;
 509         if (data_len + bss_len > rlim) {
 510                 ret = -ENOMEM;
 511                 goto err;
 512         }
 513
 514         /* Flush all traces of the currently running executable */
 515         if (id == 0) {
 516                 result = flush_old_exec(bprm);
 517                 if (result) {
 518                         ret = result;
 519                         goto err;
 520                 }
 521
 522                 /* OK, This is the point of no return */
 523                 set_personality(PER_LINUX_32BIT);
 524                 setup_new_exec(bprm);
 525         }
 526
 527         /*
 528          * calculate the extra space we need to map in
 529          */
 530         extra = max_t(unsigned long, bss_len + stack_len,
 531                         relocs * sizeof(unsigned long));
 532
 533         /*
 534          * there are a couple of cases here,  the separate code/data
 535          * case,  and then the fully copied to RAM case which lumps
 536          * it all together.
 537          */
 538         if ((flags & (FLAT_FLAG_RAM|FLAT_FLAG_GZIP)) == 0) {
 539                 /*
 540                  * this should give us a ROM ptr,  but if it doesn't we don't
 541                  * really care
 542                  */
 543                 DBG_FLT("BINFMT_FLAT: ROM mapping of file (we hope)\n");
 544
 545                 textpos = vm_mmap(bprm->file, 0, text_len, PROT_READ|PROT_EXEC,
 546                                   MAP_PRIVATE|MAP_EXECUTABLE, 0);
 547                 if (!textpos || IS_ERR_VALUE(textpos)) {
 548                         if (!textpos)
 549                                 textpos = (unsigned long) -ENOMEM;
 550                         printk("Unable to mmap process text, errno %d\n", (int)-textpos);
 551                         ret = textpos;
 552                         goto err;
 553                 }
 554
 555                 len = data_len + extra + MAX_SHARED_LIBS * sizeof(unsigned long);
 556                 len = PAGE_ALIGN(len);
 557                 realdatastart = vm_mmap(0, 0, len,
 558                         PROT_READ|PROT_WRITE|PROT_EXEC, MAP_PRIVATE, 0);
 559
 560                 if (realdatastart == 0 || IS_ERR_VALUE(realdatastart)) {
 561                         if (!realdatastart)
 562                                 realdatastart = (unsigned long) -ENOMEM;
 563                         printk("Unable to allocate RAM for process data, errno %d\n",
 564                                         (int)-realdatastart);
 565                         vm_munmap(textpos, text_len);
 566                         ret = realdatastart;
 567                         goto err;
 568                 }
 569                 datapos = ALIGN(realdatastart +
 570                                 MAX_SHARED_LIBS * sizeof(unsigned long),
 571                                 FLAT_DATA_ALIGN);
 572
 573                 DBG_FLT("BINFMT_FLAT: Allocated data+bss+stack (%d bytes): %x\n",
 574                                 (int)(data_len + bss_len + stack_len), (int)datapos);
 575
 576                 fpos = ntohl(hdr->data_start);
 577 #ifdef CONFIG_BINFMT_ZFLAT
 578                 if (flags & FLAT_FLAG_GZDATA) {
 579                         result = decompress_exec(bprm, fpos, (char *) datapos,
 580                                                  data_len + (relocs * sizeof(unsigned long)), 0);
 581                 } else
 582 #endif
 583                 {
 584                         result = bprm->file->f_op->read(bprm->file, (char *) datapos,
 585                                         data_len + (relocs * sizeof(unsigned long)), &fpos);
 586                 }
 587                 if (IS_ERR_VALUE(result)) {
 588                         printk("Unable to read data+bss, errno %d\n", (int)-result);
 589                         vm_munmap(textpos, text_len);
 590                         vm_munmap(realdatastart, len);
 591                         ret = result;
 592                         goto err;
 593                 }
 594
 595                 reloc = (unsigned long *) (datapos+(ntohl(hdr->reloc_start)-text_len));
 596                 memp = realdatastart;
 597                 memp_size = len;
 598         } else {
 599
 600                 len = text_len + data_len + extra + MAX_SHARED_LIBS * sizeof(unsigned long);
 601                 len = PAGE_ALIGN(len);
 602                 textpos = vm_mmap(0, 0, len,
 603                         PROT_READ | PROT_EXEC | PROT_WRITE, MAP_PRIVATE, 0);
 604
 605                 if (!textpos || IS_ERR_VALUE(textpos)) {
 606                         if (!textpos)
 607                                 textpos = (unsigned long) -ENOMEM;
 608                         printk("Unable to allocate RAM for process text/data, errno %d\n",
 609                                         (int)-textpos);
 610                         ret = textpos;
 611                         goto err;
 612                 }
 613
 614                 realdatastart = textpos + ntohl(hdr->data_start);
 615                 datapos = ALIGN(realdatastart +
 616                                 MAX_SHARED_LIBS * sizeof(unsigned long),
 617                                 FLAT_DATA_ALIGN);
 618
 619                 reloc = (unsigned long *)
 620                         (datapos + (ntohl(hdr->reloc_start) - text_len));
 621                 memp = textpos;
 622                 memp_size = len;
 623 #ifdef CONFIG_BINFMT_ZFLAT
 624                 /*
 625                  * load it all in and treat it like a RAM load from now on
 626                  */
 627                 if (flags & FLAT_FLAG_GZIP) {
 628                         result = decompress_exec(bprm, sizeof (struct flat_hdr),
 629                                          (((char *) textpos) + sizeof (struct flat_hdr)),
 630                                          (text_len + data_len + (relocs * sizeof(unsigned long))
 631                                                   - sizeof (struct flat_hdr)),
 632                                          0);
 633                         memmove((void *) datapos, (void *) realdatastart,
 634                                         data_len + (relocs * sizeof(unsigned long)));
 635                 } else if (flags & FLAT_FLAG_GZDATA) {
 636                         fpos = 0;
 637                         result = bprm->file->f_op->read(bprm->file,
 638                                         (char *) textpos, text_len, &fpos);
 639                         if (!IS_ERR_VALUE(result))
 640                                 result = decompress_exec(bprm, text_len, (char *) datapos,
 641                                                  data_len + (relocs * sizeof(unsigned long)), 0);
 642                 }
 643                 else
 644 #endif
 645                 {
 646                         fpos = 0;
 647                         result = bprm->file->f_op->read(bprm->file,
 648                                         (char *) textpos, text_len, &fpos);
 649                         if (!IS_ERR_VALUE(result)) {
 650                                 fpos = ntohl(hdr->data_start);
 651                                 result = bprm->file->f_op->read(bprm->file, (char *) datapos,
 652                                         data_len + (relocs * sizeof(unsigned long)), &fpos);
 653                         }
 654                 }
 655                 if (IS_ERR_VALUE(result)) {
 656                         printk("Unable to read code+data+bss, errno %d\n",(int)-result);
 657                         vm_munmap(textpos, text_len + data_len + extra +
 658                                 MAX_SHARED_LIBS * sizeof(unsigned long));
 659                         ret = result;
 660                         goto err;
 661                 }
 662         }
 663
 664         if (flags & FLAT_FLAG_KTRACE)
 665                 printk("Mapping is %x, Entry point is %x, data_start is %x\n",
 666                         (int)textpos, 0x00ffffff&ntohl(hdr->entry), ntohl(hdr->data_start));
 667
 668         /* The main program needs a little extra setup in the task structure */
 669         start_code = textpos + sizeof (struct flat_hdr);
 670         end_code = textpos + text_len;
 671         if (id == 0) {
 672                 current->mm->start_code = start_code;
 673                 current->mm->end_code = end_code;
 674                 current->mm->start_data = datapos;
 675                 current->mm->end_data = datapos + data_len;
 676                 /*
 677                  * set up the brk stuff, uses any slack left in data/bss/stack
 678                  * allocation.  We put the brk after the bss (between the bss
 679                  * and stack) like other platforms.
 680                  * Userspace code relies on the stack pointer starting out at
 681                  * an address right at the end of a page.
 682                  */
 683                 current->mm->start_brk = datapos + data_len + bss_len;
 684                 current->mm->brk = (current->mm->start_brk + 3) & ~3;
 685                 current->mm->context.end_brk = memp + memp_size - stack_len;
 686         }
 687
 688         if (flags & FLAT_FLAG_KTRACE)
 689                 printk("%s %s: TEXT=%x-%x DATA=%x-%x BSS=%x-%x\n",
 690                         id ? "Lib" : "Load", bprm->filename,
 691                         (int) start_code, (int) end_code,
 692                         (int) datapos,
 693                         (int) (datapos + data_len),
 694                         (int) (datapos + data_len),
 695                         (int) (((datapos + data_len + bss_len) + 3) & ~3));
 696
 697         text_len -= sizeof(struct flat_hdr); /* the real code len */
 698
 699         /* Store the current module values into the global library structure */
 700         libinfo->lib_list[id].start_code = start_code;
 701         libinfo->lib_list[id].start_data = datapos;
 702         libinfo->lib_list[id].start_brk = datapos + data_len + bss_len;
 703         libinfo->lib_list[id].text_len = text_len;
 704         libinfo->lib_list[id].loaded = 1;
 705         libinfo->lib_list[id].entry = (0x00ffffff & ntohl(hdr->entry)) + textpos;
 706         libinfo->lib_list[id].build_date = ntohl(hdr->build_date);
 707
 708         /*
 709          * We just load the allocations into some temporary memory to
 710          * help simplify all this mumbo jumbo
 711          *
 712          * We've got two different sections of relocation entries.
 713          * The first is the GOT which resides at the beginning of the data segment
 714          * and is terminated with a -1.  This one can be relocated in place.
 715          * The second is the extra relocation entries tacked after the image's
 716          * data segment. These require a little more processing as the entry is
 717          * really an offset into the image which contains an offset into the
 718          * image.
 719          */
 720         if (flags & FLAT_FLAG_GOTPIC) {
 721                 for (rp = (unsigned long *)datapos; *rp != 0xffffffff; rp++) {
 722                         unsigned long addr;
 723                         if (*rp) {
 724                                 addr = calc_reloc(*rp, libinfo, id, 0);
 725                                 if (addr == RELOC_FAILED) {
 726                                         ret = -ENOEXEC;
 727                                         goto err;
 728                                 }
 729                                 *rp = addr;
 730                         }
 731                 }
 732         }
 733
 734         /*
 735          * Now run through the relocation entries.
 736          * We've got to be careful here as C++ produces relocatable zero
 737          * entries in the constructor and destructor tables which are then
 738          * tested for being not zero (which will always occur unless we're
 739          * based from address zero).  This causes an endless loop as __start
 740          * is at zero.  The solution used is to not relocate zero addresses.
 741          * This has the negative side effect of not allowing a global data
 742          * reference to be statically initialised to _stext (I've moved
 743          * __start to address 4 so that is okay).
 744          */
 745         if (rev > OLD_FLAT_VERSION) {
 746                 unsigned long persistent = 0;
 747                 for (i=0; i < relocs; i++) {
 748                         unsigned long addr, relval;
 749
 750                         /* Get the address of the pointer to be
 751                            relocated (of course, the address has to be
 752                            relocated first).  */
 753                         relval = ntohl(reloc[i]);
 754                         if (flat_set_persistent (relval, &persistent))
 755                                 continue;
 756                         addr = flat_get_relocate_addr(relval);
 757                         rp = (unsigned long *) calc_reloc(addr, libinfo, id, 1);
 758                         if (rp == (unsigned long *)RELOC_FAILED) {
 759                                 ret = -ENOEXEC;
 760                                 goto err;
 761                         }
 762
 763                         /* Get the pointer's value.  */
 764                         addr = flat_get_addr_from_rp(rp, relval, flags,
 765                                                         &persistent);
 766                         if (addr != 0) {
 767                                 /*
 768                                  * Do the relocation.  PIC relocs in the data section are
 769                                  * already in target order
 770                                  */
 771                                 if ((flags & FLAT_FLAG_GOTPIC) == 0)
 772                                         addr = ntohl(addr);
 773                                 addr = calc_reloc(addr, libinfo, id, 0);
 774                                 if (addr == RELOC_FAILED) {
 775                                         ret = -ENOEXEC;
 776                                         goto err;
 777                                 }
 778
 779                                 /* Write back the relocated pointer.  */
 780                                 flat_put_addr_at_rp(rp, addr, relval);
 781                         }
 782                 }
 783         } else {
 784                 for (i=0; i < relocs; i++)
 785                         old_reloc(ntohl(reloc[i]));
 786         }
 787
 788         flush_icache_range(start_code, end_code);
 789
 790         /* zero the BSS,  BRK and stack areas */
 791         memset((void*)(datapos + data_len), 0, bss_len +
 792                         (memp + memp_size - stack_len -         /* end brk */
 793                         libinfo->lib_list[id].start_brk) +      /* start brk */
 794                         stack_len);
 795
 796         return 0;
 797 err:
 798         return ret;
 799 }
 800
 801
 802 /****************************************************************************/
 803 #ifdef CONFIG_BINFMT_SHARED_FLAT
 804
 805 /*
 806  * Load a shared library into memory.  The library gets its own data
 807  * segment (including bss) but not argv/argc/environ.
 808  */
 809
 810 static int load_flat_shared_library(int id, struct lib_info *libs)
 811 {
 812         struct linux_binprm bprm;
 813         int res;
 814         char buf[16];
 815
 816         memset(&bprm, 0, sizeof(bprm));
 817
 818         /* Create the file name */
 819         sprintf(buf, "/lib/lib%d.so", id);
 820
 821         /* Open the file up */
 822         bprm.filename = buf;
 823         bprm.file = open_exec(bprm.filename);
 824         res = PTR_ERR(bprm.file);
 825         if (IS_ERR(bprm.file))
 826                 return res;
 827
 828         bprm.cred = prepare_exec_creds();
 829         res = -ENOMEM;
 830         if (!bprm.cred)
 831                 goto out;
 832
 833         /* We don't really care about recalculating credentials at this point
 834          * as we're past the point of no return and are dealing with shared
 835          * libraries.
 836          */
 837         bprm.cred_prepared = 1;
 838
 839         res = prepare_binprm(&bprm);
 840
 841         if (!IS_ERR_VALUE(res))
 842                 res = load_flat_file(&bprm, libs, id, NULL);
 843
 844         abort_creds(bprm.cred);
 845
 846 out:
 847         allow_write_access(bprm.file);
 848         fput(bprm.file);
 849
 850         return(res);
 851 }
 852
 853 #endif /* CONFIG_BINFMT_SHARED_FLAT */
 854 /****************************************************************************/
 855
 856 /*
 857  * These are the functions used to load flat style executables and shared
 858  * libraries.  There is no binary dependent code anywhere else.
 859  */
 860
 861 static int load_flat_binary(struct linux_binprm * bprm, struct pt_regs * regs)
 862 {
 863         struct lib_info libinfo;
 864         unsigned long p = bprm->p;
 865         unsigned long stack_len;
 866         unsigned long start_addr;
 867         unsigned long *sp;
 868         int res;
 869         int i, j;
 870
 871         memset(&libinfo, 0, sizeof(libinfo));
 872         /*
 873          * We have to add the size of our arguments to our stack size
 874          * otherwise it's too easy for users to create stack overflows
 875          * by passing in a huge argument list.  And yes,  we have to be
 876          * pedantic and include space for the argv/envp array as it may have
 877          * a lot of entries.
 878          */
 879 #define TOP_OF_ARGS (PAGE_SIZE * MAX_ARG_PAGES - sizeof(void *))
 880         stack_len = TOP_OF_ARGS - bprm->p;             /* the strings */
 881         stack_len += (bprm->argc + 1) * sizeof(char *); /* the argv array */
 882         stack_len += (bprm->envc + 1) * sizeof(char *); /* the envp array */
 883         stack_len += FLAT_STACK_ALIGN - 1;  /* reserve for upcoming alignment */
 884
 885         res = load_flat_file(bprm, &libinfo, 0, &stack_len);
 886         if (IS_ERR_VALUE(res))
 887                 return res;
 888
 889         /* Update data segment pointers for all libraries */
 890         for (i=0; i<MAX_SHARED_LIBS; i++)
 891                 if (libinfo.lib_list[i].loaded)
 892                         for (j=0; j<MAX_SHARED_LIBS; j++)
 893                                 (-(j+1))[(unsigned long *)(libinfo.lib_list[i].start_data)] =
 894                                         (libinfo.lib_list[j].loaded)?
 895                                                 libinfo.lib_list[j].start_data:UNLOADED_LIB;
 896
 897         install_exec_creds(bprm);
 898
 899         set_binfmt(&flat_format);
 900
 901         p = ((current->mm->context.end_brk + stack_len + 3) & ~3) - 4;
 902         DBG_FLT("p=%x\n", (int)p);
 903
 904         /* copy the arg pages onto the stack, this could be more efficient :-) */
 905         for (i = TOP_OF_ARGS - 1; i >= bprm->p; i--)
 906                 * (char *) --p =
 907                         ((char *) page_address(bprm->page[i/PAGE_SIZE]))[i % PAGE_SIZE];
 908
 909         sp = (unsigned long *) create_flat_tables(p, bprm);
 910
 911         /* Fake some return addresses to ensure the call chain will
 912          * initialise library in order for us.  We are required to call
 913          * lib 1 first, then 2, ... and finally the main program (id 0).
 914          */
 915         start_addr = libinfo.lib_list[0].entry;
 916
 917 #ifdef CONFIG_BINFMT_SHARED_FLAT
 918         for (i = MAX_SHARED_LIBS-1; i>0; i--) {
 919                 if (libinfo.lib_list[i].loaded) {
 920                         /* Push previos first to call address */
 921                         --sp;   put_user(start_addr, sp);
 922                         start_addr = libinfo.lib_list[i].entry;
 923                 }
 924         }
 925 #endif
 926
 927         /* Stash our initial stack pointer into the mm structure */
 928         current->mm->start_stack = (unsigned long )sp;
 929
 930 #ifdef FLAT_PLAT_INIT
 931         FLAT_PLAT_INIT(regs);
 932 #endif
 933         DBG_FLT("start_thread(regs=0x%x, entry=0x%x, start_stack=0x%x)\n",
 934                 (int)regs, (int)start_addr, (int)current->mm->start_stack);
 935
 936         start_thread(regs, start_addr, current->mm->start_stack);
 937
 938         return 0;
 939 }
 940
 941 /****************************************************************************/
 942
 943 static int __init init_flat_binfmt(void)
 944 {
 945         register_binfmt(&flat_format);
 946         return 0;
 947 }
 948
 949 /****************************************************************************/
 950
 951 core_initcall(init_flat_binfmt);
 952
 953 /****************************************************************************/