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 75struct 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 88static int load_flat_shared_library(int id, struct lib_info *p); 89#endif 90 91static int load_flat_binary(struct linux_binprm *); 92static int flat_core_dump(struct coredump_params *cprm); 93 94static 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 107static 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->siginfo->si_signo); 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 121static 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 181static 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 = kernel_read(bprm->file, offset, buf, LBUFSIZE); 211 212 strm.next_in = buf; 213 strm.avail_in = ret; 214 strm.total_in = 0; 215 fpos += ret; 216 217 retval = -ENOEXEC; 218 219 /* Check minimum size -- gzip header */ 220 if (ret < 10) { 221 DBG_FLT("binfmt_flat: file too small?\n"); 222 goto out_free_buf; 223 } 224 225 /* Check gzip magic number */ 226 if ((buf[0] != 037) || ((buf[1] != 0213) && (buf[1] != 0236))) { 227 DBG_FLT("binfmt_flat: unknown compression magic?\n"); 228 goto out_free_buf; 229 } 230 231 /* Check gzip method */ 232 if (buf[2] != 8) { 233 DBG_FLT("binfmt_flat: unknown compression method?\n"); 234 goto out_free_buf; 235 } 236 /* Check gzip flags */ 237 if ((buf[3] & ENCRYPTED) || (buf[3] & CONTINUATION) || 238 (buf[3] & RESERVED)) { 239 DBG_FLT("binfmt_flat: unknown flags?\n"); 240 goto out_free_buf; 241 } 242 243 ret = 10; 244 if (buf[3] & EXTRA_FIELD) { 245 ret += 2 + buf[10] + (buf[11] << 8); 246 if (unlikely(LBUFSIZE <= ret)) { 247 DBG_FLT("binfmt_flat: buffer overflow (EXTRA)?\n"); 248 goto out_free_buf; 249 } 250 } 251 if (buf[3] & ORIG_NAME) { 252 while (ret < LBUFSIZE && buf[ret++] != 0) 253 ; 254 if (unlikely(LBUFSIZE == ret)) { 255 DBG_FLT("binfmt_flat: buffer overflow (ORIG_NAME)?\n"); 256 goto out_free_buf; 257 } 258 } 259 if (buf[3] & COMMENT) { 260 while (ret < LBUFSIZE && buf[ret++] != 0) 261 ; 262 if (unlikely(LBUFSIZE == ret)) { 263 DBG_FLT("binfmt_flat: buffer overflow (COMMENT)?\n"); 264 goto out_free_buf; 265 } 266 } 267 268 strm.next_in += ret; 269 strm.avail_in -= ret; 270 271 strm.next_out = dst; 272 strm.avail_out = len; 273 strm.total_out = 0; 274 275 if (zlib_inflateInit2(&strm, -MAX_WBITS) != Z_OK) { 276 DBG_FLT("binfmt_flat: zlib init failed?\n"); 277 goto out_free_buf; 278 } 279 280 while ((ret = zlib_inflate(&strm, Z_NO_FLUSH)) == Z_OK) { 281 ret = kernel_read(bprm->file, fpos, buf, LBUFSIZE); 282 if (ret <= 0) 283 break; 284 len -= ret; 285 286 strm.next_in = buf; 287 strm.avail_in = ret; 288 strm.total_in = 0; 289 fpos += ret; 290 } 291 292 if (ret < 0) { 293 DBG_FLT("binfmt_flat: decompression failed (%d), %s\n", 294 ret, strm.msg); 295 goto out_zlib; 296 } 297 298 retval = 0; 299out_zlib: 300 zlib_inflateEnd(&strm); 301out_free_buf: 302 kfree(buf); 303out_free: 304 kfree(strm.workspace); 305 return retval; 306} 307 308#endif /* CONFIG_BINFMT_ZFLAT */ 309 310/****************************************************************************/ 311 312static unsigned long 313calc_reloc(unsigned long r, struct lib_info *p, int curid, int internalp) 314{ 315 unsigned long addr; 316 int id; 317 unsigned long start_brk; 318 unsigned long start_data; 319 unsigned long text_len; 320 unsigned long start_code; 321 322#ifdef CONFIG_BINFMT_SHARED_FLAT 323 if (r == 0) 324 id = curid; /* Relocs of 0 are always self referring */ 325 else { 326 id = (r >> 24) & 0xff; /* Find ID for this reloc */ 327 r &= 0x00ffffff; /* Trim ID off here */ 328 } 329 if (id >= MAX_SHARED_LIBS) { 330 printk("BINFMT_FLAT: reference 0x%x to shared library %d", 331 (unsigned) r, id); 332 goto failed; 333 } 334 if (curid != id) { 335 if (internalp) { 336 printk("BINFMT_FLAT: reloc address 0x%x not in same module " 337 "(%d != %d)", (unsigned) r, curid, id); 338 goto failed; 339 } else if ( ! p->lib_list[id].loaded && 340 IS_ERR_VALUE(load_flat_shared_library(id, p))) { 341 printk("BINFMT_FLAT: failed to load library %d", id); 342 goto failed; 343 } 344 /* Check versioning information (i.e. time stamps) */ 345 if (p->lib_list[id].build_date && p->lib_list[curid].build_date && 346 p->lib_list[curid].build_date < p->lib_list[id].build_date) { 347 printk("BINFMT_FLAT: library %d is younger than %d", id, curid); 348 goto failed; 349 } 350 } 351#else 352 id = 0; 353#endif 354 355 start_brk = p->lib_list[id].start_brk; 356 start_data = p->lib_list[id].start_data; 357 start_code = p->lib_list[id].start_code; 358 text_len = p->lib_list[id].text_len; 359 360 if (!flat_reloc_valid(r, start_brk - start_data + text_len)) { 361 printk("BINFMT_FLAT: reloc outside program 0x%x (0 - 0x%x/0x%x)", 362 (int) r,(int)(start_brk-start_data+text_len),(int)text_len); 363 goto failed; 364 } 365 366 if (r < text_len) /* In text segment */ 367 addr = r + start_code; 368 else /* In data segment */ 369 addr = r - text_len + start_data; 370 371 /* Range checked already above so doing the range tests is redundant...*/ 372 return(addr); 373 374failed: 375 printk(", killing %s!\n", current->comm); 376 send_sig(SIGSEGV, current, 0); 377 378 return RELOC_FAILED; 379} 380 381/****************************************************************************/ 382 383static void old_reloc(unsigned long rl) 384{ 385#ifdef DEBUG 386 char *segment[] = { "TEXT", "DATA", "BSS", "*UNKNOWN*" }; 387#endif 388 flat_v2_reloc_t r; 389 unsigned long *ptr; 390 391 r.value = rl; 392#if defined(CONFIG_COLDFIRE) 393 ptr = (unsigned long *) (current->mm->start_code + r.reloc.offset); 394#else 395 ptr = (unsigned long *) (current->mm->start_data + r.reloc.offset); 396#endif 397 398#ifdef DEBUG 399 printk("Relocation of variable at DATASEG+%x " 400 "(address %p, currently %x) into segment %s\n", 401 r.reloc.offset, ptr, (int)*ptr, segment[r.reloc.type]); 402#endif 403 404 switch (r.reloc.type) { 405 case OLD_FLAT_RELOC_TYPE_TEXT: 406 *ptr += current->mm->start_code; 407 break; 408 case OLD_FLAT_RELOC_TYPE_DATA: 409 *ptr += current->mm->start_data; 410 break; 411 case OLD_FLAT_RELOC_TYPE_BSS: 412 *ptr += current->mm->end_data; 413 break; 414 default: 415 printk("BINFMT_FLAT: Unknown relocation type=%x\n", r.reloc.type); 416 break; 417 } 418 419#ifdef DEBUG 420 printk("Relocation became %x\n", (int)*ptr); 421#endif 422} 423 424/****************************************************************************/ 425 426static int load_flat_file(struct linux_binprm * bprm, 427 struct lib_info *libinfo, int id, unsigned long *extra_stack) 428{ 429 struct flat_hdr * hdr; 430 unsigned long textpos = 0, datapos = 0, result; 431 unsigned long realdatastart = 0; 432 unsigned long text_len, data_len, bss_len, stack_len, flags; 433 unsigned long full_data; 434 unsigned long len, memp = 0; 435 unsigned long memp_size, extra, rlim; 436 unsigned long *reloc = 0, *rp; 437 struct inode *inode; 438 int i, rev, relocs = 0; 439 loff_t fpos; 440 unsigned long start_code, end_code; 441 int ret; 442 443 hdr = ((struct flat_hdr *) bprm->buf); /* exec-header */ 444 inode = file_inode(bprm->file); 445 446 text_len = ntohl(hdr->data_start); 447 data_len = ntohl(hdr->data_end) - ntohl(hdr->data_start); 448 bss_len = ntohl(hdr->bss_end) - ntohl(hdr->data_end); 449 stack_len = ntohl(hdr->stack_size); 450 if (extra_stack) { 451 stack_len += *extra_stack; 452 *extra_stack = stack_len; 453 } 454 relocs = ntohl(hdr->reloc_count); 455 flags = ntohl(hdr->flags); 456 rev = ntohl(hdr->rev); 457 full_data = data_len + relocs * sizeof(unsigned long); 458 459 if (strncmp(hdr->magic, "bFLT", 4)) { 460 /* 461 * Previously, here was a printk to tell people 462 * "BINFMT_FLAT: bad header magic". 463 * But for the kernel which also use ELF FD-PIC format, this 464 * error message is confusing. 465 * because a lot of people do not manage to produce good 466 */ 467 ret = -ENOEXEC; 468 goto err; 469 } 470 471 if (flags & FLAT_FLAG_KTRACE) 472 printk("BINFMT_FLAT: Loading file: %s\n", bprm->filename); 473 474 if (rev != FLAT_VERSION && rev != OLD_FLAT_VERSION) { 475 printk("BINFMT_FLAT: bad flat file version 0x%x (supported " 476 "0x%lx and 0x%lx)\n", 477 rev, FLAT_VERSION, OLD_FLAT_VERSION); 478 ret = -ENOEXEC; 479 goto err; 480 } 481 482 /* Don't allow old format executables to use shared libraries */ 483 if (rev == OLD_FLAT_VERSION && id != 0) { 484 printk("BINFMT_FLAT: shared libraries are not available before rev 0x%x\n", 485 (int) FLAT_VERSION); 486 ret = -ENOEXEC; 487 goto err; 488 } 489 490 /* 491 * fix up the flags for the older format, there were all kinds 492 * of endian hacks, this only works for the simple cases 493 */ 494 if (rev == OLD_FLAT_VERSION && flat_old_ram_flag(flags)) 495 flags = FLAT_FLAG_RAM; 496 497#ifndef CONFIG_BINFMT_ZFLAT 498 if (flags & (FLAT_FLAG_GZIP|FLAT_FLAG_GZDATA)) { 499 printk("Support for ZFLAT executables is not enabled.\n"); 500 ret = -ENOEXEC; 501 goto err; 502 } 503#endif 504 505 /* 506 * Check initial limits. This avoids letting people circumvent 507 * size limits imposed on them by creating programs with large 508 * arrays in the data or bss. 509 */ 510 rlim = rlimit(RLIMIT_DATA); 511 if (rlim >= RLIM_INFINITY) 512 rlim = ~0; 513 if (data_len + bss_len > rlim) { 514 ret = -ENOMEM; 515 goto err; 516 } 517 518 /* Flush all traces of the currently running executable */ 519 if (id == 0) { 520 result = flush_old_exec(bprm); 521 if (result) { 522 ret = result; 523 goto err; 524 } 525 526 /* OK, This is the point of no return */ 527 set_personality(PER_LINUX_32BIT); 528 setup_new_exec(bprm); 529 } 530 531 /* 532 * calculate the extra space we need to map in 533 */ 534 extra = max_t(unsigned long, bss_len + stack_len, 535 relocs * sizeof(unsigned long)); 536 537 /* 538 * there are a couple of cases here, the separate code/data 539 * case, and then the fully copied to RAM case which lumps 540 * it all together. 541 */ 542 if ((flags & (FLAT_FLAG_RAM|FLAT_FLAG_GZIP)) == 0) { 543 /* 544 * this should give us a ROM ptr, but if it doesn't we don't 545 * really care 546 */ 547 DBG_FLT("BINFMT_FLAT: ROM mapping of file (we hope)\n"); 548 549 textpos = vm_mmap(bprm->file, 0, text_len, PROT_READ|PROT_EXEC, 550 MAP_PRIVATE|MAP_EXECUTABLE, 0); 551 if (!textpos || IS_ERR_VALUE(textpos)) { 552 if (!textpos) 553 textpos = (unsigned long) -ENOMEM; 554 printk("Unable to mmap process text, errno %d\n", (int)-textpos); 555 ret = textpos; 556 goto err; 557 } 558 559 len = data_len + extra + MAX_SHARED_LIBS * sizeof(unsigned long); 560 len = PAGE_ALIGN(len); 561 realdatastart = vm_mmap(0, 0, len, 562 PROT_READ|PROT_WRITE|PROT_EXEC, MAP_PRIVATE, 0); 563 564 if (realdatastart == 0 || IS_ERR_VALUE(realdatastart)) { 565 if (!realdatastart) 566 realdatastart = (unsigned long) -ENOMEM; 567 printk("Unable to allocate RAM for process data, errno %d\n", 568 (int)-realdatastart); 569 vm_munmap(textpos, text_len); 570 ret = realdatastart; 571 goto err; 572 } 573 datapos = ALIGN(realdatastart + 574 MAX_SHARED_LIBS * sizeof(unsigned long), 575 FLAT_DATA_ALIGN); 576 577 DBG_FLT("BINFMT_FLAT: Allocated data+bss+stack (%d bytes): %x\n", 578 (int)(data_len + bss_len + stack_len), (int)datapos); 579 580 fpos = ntohl(hdr->data_start); 581#ifdef CONFIG_BINFMT_ZFLAT 582 if (flags & FLAT_FLAG_GZDATA) { 583 result = decompress_exec(bprm, fpos, (char *) datapos, 584 full_data, 0); 585 } else 586#endif 587 { 588 result = read_code(bprm->file, datapos, fpos, 589 full_data); 590 } 591 if (IS_ERR_VALUE(result)) { 592 printk("Unable to read data+bss, errno %d\n", (int)-result); 593 vm_munmap(textpos, text_len); 594 vm_munmap(realdatastart, len); 595 ret = result; 596 goto err; 597 } 598 599 reloc = (unsigned long *) (datapos+(ntohl(hdr->reloc_start)-text_len)); 600 memp = realdatastart; 601 memp_size = len; 602 } else { 603 604 len = text_len + data_len + extra + MAX_SHARED_LIBS * sizeof(unsigned long); 605 len = PAGE_ALIGN(len); 606 textpos = vm_mmap(0, 0, len, 607 PROT_READ | PROT_EXEC | PROT_WRITE, MAP_PRIVATE, 0); 608 609 if (!textpos || IS_ERR_VALUE(textpos)) { 610 if (!textpos) 611 textpos = (unsigned long) -ENOMEM; 612 printk("Unable to allocate RAM for process text/data, errno %d\n", 613 (int)-textpos); 614 ret = textpos; 615 goto err; 616 } 617 618 realdatastart = textpos + ntohl(hdr->data_start); 619 datapos = ALIGN(realdatastart + 620 MAX_SHARED_LIBS * sizeof(unsigned long), 621 FLAT_DATA_ALIGN); 622 623 reloc = (unsigned long *) 624 (datapos + (ntohl(hdr->reloc_start) - text_len)); 625 memp = textpos; 626 memp_size = len; 627#ifdef CONFIG_BINFMT_ZFLAT 628 /* 629 * load it all in and treat it like a RAM load from now on 630 */ 631 if (flags & FLAT_FLAG_GZIP) { 632 result = decompress_exec(bprm, sizeof (struct flat_hdr), 633 (((char *) textpos) + sizeof (struct flat_hdr)), 634 (text_len + full_data 635 - sizeof (struct flat_hdr)), 636 0); 637 memmove((void *) datapos, (void *) realdatastart, 638 full_data); 639 } else if (flags & FLAT_FLAG_GZDATA) { 640 result = read_code(bprm->file, textpos, 0, text_len); 641 if (!IS_ERR_VALUE(result)) 642 result = decompress_exec(bprm, text_len, (char *) datapos, 643 full_data, 0); 644 } 645 else 646#endif 647 { 648 result = read_code(bprm->file, textpos, 0, text_len); 649 if (!IS_ERR_VALUE(result)) 650 result = read_code(bprm->file, datapos, 651 ntohl(hdr->data_start), 652 full_data); 653 } 654 if (IS_ERR_VALUE(result)) { 655 printk("Unable to read code+data+bss, errno %d\n",(int)-result); 656 vm_munmap(textpos, text_len + data_len + extra + 657 MAX_SHARED_LIBS * sizeof(unsigned long)); 658 ret = result; 659 goto err; 660 } 661 } 662 663 if (flags & FLAT_FLAG_KTRACE) 664 printk("Mapping is %x, Entry point is %x, data_start is %x\n", 665 (int)textpos, 0x00ffffff&ntohl(hdr->entry), ntohl(hdr->data_start)); 666 667 /* The main program needs a little extra setup in the task structure */ 668 start_code = textpos + sizeof (struct flat_hdr); 669 end_code = textpos + text_len; 670 if (id == 0) { 671 current->mm->start_code = start_code; 672 current->mm->end_code = end_code; 673 current->mm->start_data = datapos; 674 current->mm->end_data = datapos + data_len; 675 /* 676 * set up the brk stuff, uses any slack left in data/bss/stack 677 * allocation. We put the brk after the bss (between the bss 678 * and stack) like other platforms. 679 * Userspace code relies on the stack pointer starting out at 680 * an address right at the end of a page. 681 */ 682 current->mm->start_brk = datapos + data_len + bss_len; 683 current->mm->brk = (current->mm->start_brk + 3) & ~3; 684 current->mm->context.end_brk = memp + memp_size - stack_len; 685 } 686 687 if (flags & FLAT_FLAG_KTRACE) 688 printk("%s %s: TEXT=%x-%x DATA=%x-%x BSS=%x-%x\n", 689 id ? "Lib" : "Load", bprm->filename, 690 (int) start_code, (int) end_code, 691 (int) datapos, 692 (int) (datapos + data_len), 693 (int) (datapos + data_len), 694 (int) (((datapos + data_len + bss_len) + 3) & ~3)); 695 696 text_len -= sizeof(struct flat_hdr); /* the real code len */ 697 698 /* Store the current module values into the global library structure */ 699 libinfo->lib_list[id].start_code = start_code; 700 libinfo->lib_list[id].start_data = datapos; 701 libinfo->lib_list[id].start_brk = datapos + data_len + bss_len; 702 libinfo->lib_list[id].text_len = text_len; 703 libinfo->lib_list[id].loaded = 1; 704 libinfo->lib_list[id].entry = (0x00ffffff & ntohl(hdr->entry)) + textpos; 705 libinfo->lib_list[id].build_date = ntohl(hdr->build_date); 706 707 /* 708 * We just load the allocations into some temporary memory to 709 * help simplify all this mumbo jumbo 710 * 711 * We've got two different sections of relocation entries. 712 * The first is the GOT which resides at the beginning of the data segment 713 * and is terminated with a -1. This one can be relocated in place. 714 * The second is the extra relocation entries tacked after the image's 715 * data segment. These require a little more processing as the entry is 716 * really an offset into the image which contains an offset into the 717 * image. 718 */ 719 if (flags & FLAT_FLAG_GOTPIC) { 720 for (rp = (unsigned long *)datapos; *rp != 0xffffffff; rp++) { 721 unsigned long addr; 722 if (*rp) { 723 addr = calc_reloc(*rp, libinfo, id, 0); 724 if (addr == RELOC_FAILED) { 725 ret = -ENOEXEC; 726 goto err; 727 } 728 *rp = addr; 729 } 730 } 731 } 732 733 /* 734 * Now run through the relocation entries. 735 * We've got to be careful here as C++ produces relocatable zero 736 * entries in the constructor and destructor tables which are then 737 * tested for being not zero (which will always occur unless we're 738 * based from address zero). This causes an endless loop as __start 739 * is at zero. The solution used is to not relocate zero addresses. 740 * This has the negative side effect of not allowing a global data 741 * reference to be statically initialised to _stext (I've moved 742 * __start to address 4 so that is okay). 743 */ 744 if (rev > OLD_FLAT_VERSION) { 745 unsigned long persistent = 0; 746 for (i=0; i < relocs; i++) { 747 unsigned long addr, relval; 748 749 /* Get the address of the pointer to be 750 relocated (of course, the address has to be 751 relocated first). */ 752 relval = ntohl(reloc[i]); 753 if (flat_set_persistent (relval, &persistent)) 754 continue; 755 addr = flat_get_relocate_addr(relval); 756 rp = (unsigned long *) calc_reloc(addr, libinfo, id, 1); 757 if (rp == (unsigned long *)RELOC_FAILED) { 758 ret = -ENOEXEC; 759 goto err; 760 } 761 762 /* Get the pointer's value. */ 763 addr = flat_get_addr_from_rp(rp, relval, flags, 764 &persistent); 765 if (addr != 0) { 766 /* 767 * Do the relocation. PIC relocs in the data section are 768 * already in target order 769 */ 770 if ((flags & FLAT_FLAG_GOTPIC) == 0) 771 addr = ntohl(addr); 772 addr = calc_reloc(addr, libinfo, id, 0); 773 if (addr == RELOC_FAILED) { 774 ret = -ENOEXEC; 775 goto err; 776 } 777 778 /* Write back the relocated pointer. */ 779 flat_put_addr_at_rp(rp, addr, relval); 780 } 781 } 782 } else { 783 for (i=0; i < relocs; i++) 784 old_reloc(ntohl(reloc[i])); 785 } 786 787 flush_icache_range(start_code, end_code); 788 789 /* zero the BSS, BRK and stack areas */ 790 memset((void*)(datapos + data_len), 0, bss_len + 791 (memp + memp_size - stack_len - /* end brk */ 792 libinfo->lib_list[id].start_brk) + /* start brk */ 793 stack_len); 794 795 return 0; 796err: 797 return ret; 798} 799 800 801/****************************************************************************/ 802#ifdef CONFIG_BINFMT_SHARED_FLAT 803 804/* 805 * Load a shared library into memory. The library gets its own data 806 * segment (including bss) but not argv/argc/environ. 807 */ 808 809static int load_flat_shared_library(int id, struct lib_info *libs) 810{ 811 struct linux_binprm bprm; 812 int res; 813 char buf[16]; 814 815 memset(&bprm, 0, sizeof(bprm)); 816 817 /* Create the file name */ 818 sprintf(buf, "/lib/lib%d.so", id); 819 820 /* Open the file up */ 821 bprm.filename = buf; 822 bprm.file = open_exec(bprm.filename); 823 res = PTR_ERR(bprm.file); 824 if (IS_ERR(bprm.file)) 825 return res; 826 827 bprm.cred = prepare_exec_creds(); 828 res = -ENOMEM; 829 if (!bprm.cred) 830 goto out; 831 832 /* We don't really care about recalculating credentials at this point 833 * as we're past the point of no return and are dealing with shared 834 * libraries. 835 */ 836 bprm.cred_prepared = 1; 837 838 res = prepare_binprm(&bprm); 839 840 if (!IS_ERR_VALUE(res)) 841 res = load_flat_file(&bprm, libs, id, NULL); 842 843 abort_creds(bprm.cred); 844 845out: 846 allow_write_access(bprm.file); 847 fput(bprm.file); 848 849 return(res); 850} 851 852#endif /* CONFIG_BINFMT_SHARED_FLAT */ 853/****************************************************************************/ 854 855/* 856 * These are the functions used to load flat style executables and shared 857 * libraries. There is no binary dependent code anywhere else. 858 */ 859 860static int load_flat_binary(struct linux_binprm * bprm) 861{ 862 struct lib_info libinfo; 863 struct pt_regs *regs = current_pt_regs(); 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 943static int __init init_flat_binfmt(void) 944{ 945 register_binfmt(&flat_format); 946 return 0; 947} 948 949/****************************************************************************/ 950 951core_initcall(init_flat_binfmt); 952 953/****************************************************************************/ 954