release/src-rt-6.x.4708/linux/linux-2.6.36/arch/x86/ia32/ia32_aout.c

   1 /*
   2  *  a.out loader for x86-64
   3  *
   4  *  Copyright (C) 1991, 1992, 1996  Linus Torvalds
   5  *  Hacked together by Andi Kleen
   6  */
   7
   8 #include <linux/module.h>
   9
  10 #include <linux/time.h>
  11 #include <linux/kernel.h>
  12 #include <linux/mm.h>
  13 #include <linux/mman.h>
  14 #include <linux/a.out.h>
  15 #include <linux/errno.h>
  16 #include <linux/signal.h>
  17 #include <linux/string.h>
  18 #include <linux/fs.h>
  19 #include <linux/file.h>
  20 #include <linux/stat.h>
  21 #include <linux/fcntl.h>
  22 #include <linux/ptrace.h>
  23 #include <linux/user.h>
  24 #include <linux/binfmts.h>
  25 #include <linux/personality.h>
  26 #include <linux/init.h>
  27 #include <linux/jiffies.h>
  28
  29 #include <asm/system.h>
  30 #include <asm/uaccess.h>
  31 #include <asm/pgalloc.h>
  32 #include <asm/cacheflush.h>
  33 #include <asm/user32.h>
  34 #include <asm/ia32.h>
  35
  36 #undef WARN_OLD
  37 #undef CORE_DUMP /* definitely broken */
  38
  39 static int load_aout_binary(struct linux_binprm *, struct pt_regs *regs);
  40 static int load_aout_library(struct file *);
  41
  42 #ifdef CORE_DUMP
  43 static int aout_core_dump(long signr, struct pt_regs *regs, struct file *file,
  44                           unsigned long limit);
  45
  46 /*
  47  * fill in the user structure for a core dump..
  48  */
  49 static void dump_thread32(struct pt_regs *regs, struct user32 *dump)
  50 {
  51         u32 fs, gs;
  52
  53 /* changed the size calculations - should hopefully work better. lbt */
  54         dump->magic = CMAGIC;
  55         dump->start_code = 0;
  56         dump->start_stack = regs->sp & ~(PAGE_SIZE - 1);
  57         dump->u_tsize = ((unsigned long) current->mm->end_code) >> PAGE_SHIFT;
  58         dump->u_dsize = ((unsigned long)
  59                          (current->mm->brk + (PAGE_SIZE-1))) >> PAGE_SHIFT;
  60         dump->u_dsize -= dump->u_tsize;
  61         dump->u_ssize = 0;
  62         dump->u_debugreg[0] = current->thread.debugreg0;
  63         dump->u_debugreg[1] = current->thread.debugreg1;
  64         dump->u_debugreg[2] = current->thread.debugreg2;
  65         dump->u_debugreg[3] = current->thread.debugreg3;
  66         dump->u_debugreg[4] = 0;
  67         dump->u_debugreg[5] = 0;
  68         dump->u_debugreg[6] = current->thread.debugreg6;
  69         dump->u_debugreg[7] = current->thread.debugreg7;
  70
  71         if (dump->start_stack < 0xc0000000) {
  72                 unsigned long tmp;
  73
  74                 tmp = (unsigned long) (0xc0000000 - dump->start_stack);
  75                 dump->u_ssize = tmp >> PAGE_SHIFT;
  76         }
  77
  78         dump->regs.bx = regs->bx;
  79         dump->regs.cx = regs->cx;
  80         dump->regs.dx = regs->dx;
  81         dump->regs.si = regs->si;
  82         dump->regs.di = regs->di;
  83         dump->regs.bp = regs->bp;
  84         dump->regs.ax = regs->ax;
  85         dump->regs.ds = current->thread.ds;
  86         dump->regs.es = current->thread.es;
  87         savesegment(fs, fs);
  88         dump->regs.fs = fs;
  89         savesegment(gs, gs);
  90         dump->regs.gs = gs;
  91         dump->regs.orig_ax = regs->orig_ax;
  92         dump->regs.ip = regs->ip;
  93         dump->regs.cs = regs->cs;
  94         dump->regs.flags = regs->flags;
  95         dump->regs.sp = regs->sp;
  96         dump->regs.ss = regs->ss;
  97
  98         dump->u_fpvalid = 0;
  99 }
 100
 101 #endif
 102
 103 static struct linux_binfmt aout_format = {
 104         .module         = THIS_MODULE,
 105         .load_binary    = load_aout_binary,
 106         .load_shlib     = load_aout_library,
 107 #ifdef CORE_DUMP
 108         .core_dump      = aout_core_dump,
 109 #endif
 110         .min_coredump   = PAGE_SIZE
 111 };
 112
 113 static void set_brk(unsigned long start, unsigned long end)
 114 {
 115         start = PAGE_ALIGN(start);
 116         end = PAGE_ALIGN(end);
 117         if (end <= start)
 118                 return;
 119         down_write(&current->mm->mmap_sem);
 120         do_brk(start, end - start);
 121         up_write(&current->mm->mmap_sem);
 122 }
 123
 124 #ifdef CORE_DUMP
 125 /*
 126  * These are the only things you should do on a core-file: use only these
 127  * macros to write out all the necessary info.
 128  */
 129
 130 #include <linux/coredump.h>
 131
 132 #define DUMP_WRITE(addr, nr)                         \
 133         if (!dump_write(file, (void *)(addr), (nr))) \
 134                 goto end_coredump;
 135
 136 #define DUMP_SEEK(offset)               \
 137         if (!dump_seek(file, offset))   \
 138                 goto end_coredump;
 139
 140 #define START_DATA()    (u.u_tsize << PAGE_SHIFT)
 141 #define START_STACK(u)  (u.start_stack)
 142
 143 /*
 144  * Routine writes a core dump image in the current directory.
 145  * Currently only a stub-function.
 146  *
 147  * Note that setuid/setgid files won't make a core-dump if the uid/gid
 148  * changed due to the set[u|g]id. It's enforced by the "current->mm->dumpable"
 149  * field, which also makes sure the core-dumps won't be recursive if the
 150  * dumping of the process results in another error..
 151  */
 152
 153 static int aout_core_dump(long signr, struct pt_regs *regs, struct file *file,
 154                           unsigned long limit)
 155 {
 156         mm_segment_t fs;
 157         int has_dumped = 0;
 158         unsigned long dump_start, dump_size;
 159         struct user32 dump;
 160
 161         fs = get_fs();
 162         set_fs(KERNEL_DS);
 163         has_dumped = 1;
 164         current->flags |= PF_DUMPCORE;
 165         strncpy(dump.u_comm, current->comm, sizeof(current->comm));
 166         dump.u_ar0 = offsetof(struct user32, regs);
 167         dump.signal = signr;
 168         dump_thread32(regs, &dump);
 169
 170         /*
 171          * If the size of the dump file exceeds the rlimit, then see
 172          * what would happen if we wrote the stack, but not the data
 173          * area.
 174          */
 175         if ((dump.u_dsize + dump.u_ssize + 1) * PAGE_SIZE > limit)
 176                 dump.u_dsize = 0;
 177
 178         /* Make sure we have enough room to write the stack and data areas. */
 179         if ((dump.u_ssize + 1) * PAGE_SIZE > limit)
 180                 dump.u_ssize = 0;
 181
 182         /* make sure we actually have a data and stack area to dump */
 183         set_fs(USER_DS);
 184         if (!access_ok(VERIFY_READ, (void *) (unsigned long)START_DATA(dump),
 185                        dump.u_dsize << PAGE_SHIFT))
 186                 dump.u_dsize = 0;
 187         if (!access_ok(VERIFY_READ, (void *) (unsigned long)START_STACK(dump),
 188                        dump.u_ssize << PAGE_SHIFT))
 189                 dump.u_ssize = 0;
 190
 191         set_fs(KERNEL_DS);
 192         /* struct user */
 193         DUMP_WRITE(&dump, sizeof(dump));
 194         /* Now dump all of the user data.  Include malloced stuff as well */
 195         DUMP_SEEK(PAGE_SIZE);
 196         /* now we start writing out the user space info */
 197         set_fs(USER_DS);
 198         /* Dump the data area */
 199         if (dump.u_dsize != 0) {
 200                 dump_start = START_DATA(dump);
 201                 dump_size = dump.u_dsize << PAGE_SHIFT;
 202                 DUMP_WRITE(dump_start, dump_size);
 203         }
 204         /* Now prepare to dump the stack area */
 205         if (dump.u_ssize != 0) {
 206                 dump_start = START_STACK(dump);
 207                 dump_size = dump.u_ssize << PAGE_SHIFT;
 208                 DUMP_WRITE(dump_start, dump_size);
 209         }
 210 end_coredump:
 211         set_fs(fs);
 212         return has_dumped;
 213 }
 214 #endif
 215
 216 /*
 217  * create_aout_tables() parses the env- and arg-strings in new user
 218  * memory and creates the pointer tables from them, and puts their
 219  * addresses on the "stack", returning the new stack pointer value.
 220  */
 221 static u32 __user *create_aout_tables(char __user *p, struct linux_binprm *bprm)
 222 {
 223         u32 __user *argv, *envp, *sp;
 224         int argc = bprm->argc, envc = bprm->envc;
 225
 226         sp = (u32 __user *) ((-(unsigned long)sizeof(u32)) & (unsigned long) p);
 227         sp -= envc+1;
 228         envp = sp;
 229         sp -= argc+1;
 230         argv = sp;
 231         put_user((unsigned long) envp, --sp);
 232         put_user((unsigned long) argv, --sp);
 233         put_user(argc, --sp);
 234         current->mm->arg_start = (unsigned long) p;
 235         while (argc-- > 0) {
 236                 char c;
 237
 238                 put_user((u32)(unsigned long)p, argv++);
 239                 do {
 240                         get_user(c, p++);
 241                 } while (c);
 242         }
 243         put_user(0, argv);
 244         current->mm->arg_end = current->mm->env_start = (unsigned long) p;
 245         while (envc-- > 0) {
 246                 char c;
 247
 248                 put_user((u32)(unsigned long)p, envp++);
 249                 do {
 250                         get_user(c, p++);
 251                 } while (c);
 252         }
 253         put_user(0, envp);
 254         current->mm->env_end = (unsigned long) p;
 255         return sp;
 256 }
 257
 258 /*
 259  * These are the functions used to load a.out style executables and shared
 260  * libraries.  There is no binary dependent code anywhere else.
 261  */
 262 static int load_aout_binary(struct linux_binprm *bprm, struct pt_regs *regs)
 263 {
 264         unsigned long error, fd_offset, rlim;
 265         struct exec ex;
 266         int retval;
 267
 268         ex = *((struct exec *) bprm->buf);              /* exec-header */
 269         if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != OMAGIC &&
 270              N_MAGIC(ex) != QMAGIC && N_MAGIC(ex) != NMAGIC) ||
 271             N_TRSIZE(ex) || N_DRSIZE(ex) ||
 272             i_size_read(bprm->file->f_path.dentry->d_inode) <
 273             ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) {
 274                 return -ENOEXEC;
 275         }
 276
 277         fd_offset = N_TXTOFF(ex);
 278
 279         /* Check initial limits. This avoids letting people circumvent
 280          * size limits imposed on them by creating programs with large
 281          * arrays in the data or bss.
 282          */
 283         rlim = rlimit(RLIMIT_DATA);
 284         if (rlim >= RLIM_INFINITY)
 285                 rlim = ~0;
 286         if (ex.a_data + ex.a_bss > rlim)
 287                 return -ENOMEM;
 288
 289         /* Flush all traces of the currently running executable */
 290         retval = flush_old_exec(bprm);
 291         if (retval)
 292                 return retval;
 293
 294         /* OK, This is the point of no return */
 295         set_personality(PER_LINUX);
 296         set_thread_flag(TIF_IA32);
 297
 298         setup_new_exec(bprm);
 299
 300         regs->cs = __USER32_CS;
 301         regs->r8 = regs->r9 = regs->r10 = regs->r11 = regs->r12 =
 302                 regs->r13 = regs->r14 = regs->r15 = 0;
 303
 304         current->mm->end_code = ex.a_text +
 305                 (current->mm->start_code = N_TXTADDR(ex));
 306         current->mm->end_data = ex.a_data +
 307                 (current->mm->start_data = N_DATADDR(ex));
 308         current->mm->brk = ex.a_bss +
 309                 (current->mm->start_brk = N_BSSADDR(ex));
 310         current->mm->free_area_cache = TASK_UNMAPPED_BASE;
 311         current->mm->cached_hole_size = 0;
 312
 313         install_exec_creds(bprm);
 314         current->flags &= ~PF_FORKNOEXEC;
 315
 316         if (N_MAGIC(ex) == OMAGIC) {
 317                 unsigned long text_addr, map_size;
 318                 loff_t pos;
 319
 320                 text_addr = N_TXTADDR(ex);
 321
 322                 pos = 32;
 323                 map_size = ex.a_text+ex.a_data;
 324
 325                 down_write(&current->mm->mmap_sem);
 326                 error = do_brk(text_addr & PAGE_MASK, map_size);
 327                 up_write(&current->mm->mmap_sem);
 328
 329                 if (error != (text_addr & PAGE_MASK)) {
 330                         send_sig(SIGKILL, current, 0);
 331                         return error;
 332                 }
 333
 334                 error = bprm->file->f_op->read(bprm->file,
 335                          (char __user *)text_addr,
 336                           ex.a_text+ex.a_data, &pos);
 337                 if ((signed long)error < 0) {
 338                         send_sig(SIGKILL, current, 0);
 339                         return error;
 340                 }
 341
 342                 flush_icache_range(text_addr, text_addr+ex.a_text+ex.a_data);
 343         } else {
 344 #ifdef WARN_OLD
 345                 static unsigned long error_time, error_time2;
 346                 if ((ex.a_text & 0xfff || ex.a_data & 0xfff) &&
 347                     (N_MAGIC(ex) != NMAGIC) &&
 348                                 time_after(jiffies, error_time2 + 5*HZ)) {
 349                         printk(KERN_NOTICE "executable not page aligned\n");
 350                         error_time2 = jiffies;
 351                 }
 352
 353                 if ((fd_offset & ~PAGE_MASK) != 0 &&
 354                             time_after(jiffies, error_time + 5*HZ)) {
 355                         printk(KERN_WARNING
 356                                "fd_offset is not page aligned. Please convert "
 357                                "program: %s\n",
 358                                bprm->file->f_path.dentry->d_name.name);
 359                         error_time = jiffies;
 360                 }
 361 #endif
 362
 363                 if (!bprm->file->f_op->mmap || (fd_offset & ~PAGE_MASK) != 0) {
 364                         loff_t pos = fd_offset;
 365
 366                         down_write(&current->mm->mmap_sem);
 367                         do_brk(N_TXTADDR(ex), ex.a_text+ex.a_data);
 368                         up_write(&current->mm->mmap_sem);
 369                         bprm->file->f_op->read(bprm->file,
 370                                         (char __user *)N_TXTADDR(ex),
 371                                         ex.a_text+ex.a_data, &pos);
 372                         flush_icache_range((unsigned long) N_TXTADDR(ex),
 373                                            (unsigned long) N_TXTADDR(ex) +
 374                                            ex.a_text+ex.a_data);
 375                         goto beyond_if;
 376                 }
 377
 378                 down_write(&current->mm->mmap_sem);
 379                 error = do_mmap(bprm->file, N_TXTADDR(ex), ex.a_text,
 380                                 PROT_READ | PROT_EXEC,
 381                                 MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE |
 382                                 MAP_EXECUTABLE | MAP_32BIT,
 383                                 fd_offset);
 384                 up_write(&current->mm->mmap_sem);
 385
 386                 if (error != N_TXTADDR(ex)) {
 387                         send_sig(SIGKILL, current, 0);
 388                         return error;
 389                 }
 390
 391                 down_write(&current->mm->mmap_sem);
 392                 error = do_mmap(bprm->file, N_DATADDR(ex), ex.a_data,
 393                                 PROT_READ | PROT_WRITE | PROT_EXEC,
 394                                 MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE |
 395                                 MAP_EXECUTABLE | MAP_32BIT,
 396                                 fd_offset + ex.a_text);
 397                 up_write(&current->mm->mmap_sem);
 398                 if (error != N_DATADDR(ex)) {
 399                         send_sig(SIGKILL, current, 0);
 400                         return error;
 401                 }
 402         }
 403 beyond_if:
 404         set_binfmt(&aout_format);
 405
 406         set_brk(current->mm->start_brk, current->mm->brk);
 407
 408         retval = setup_arg_pages(bprm, IA32_STACK_TOP, EXSTACK_DEFAULT);
 409         if (retval < 0) {
 410                 /* Someone check-me: is this error path enough? */
 411                 send_sig(SIGKILL, current, 0);
 412                 return retval;
 413         }
 414
 415         current->mm->start_stack =
 416                 (unsigned long)create_aout_tables((char __user *)bprm->p, bprm);
 417         /* start thread */
 418         loadsegment(fs, 0);
 419         loadsegment(ds, __USER32_DS);
 420         loadsegment(es, __USER32_DS);
 421         load_gs_index(0);
 422         (regs)->ip = ex.a_entry;
 423         (regs)->sp = current->mm->start_stack;
 424         (regs)->flags = 0x200;
 425         (regs)->cs = __USER32_CS;
 426         (regs)->ss = __USER32_DS;
 427         regs->r8 = regs->r9 = regs->r10 = regs->r11 =
 428         regs->r12 = regs->r13 = regs->r14 = regs->r15 = 0;
 429         set_fs(USER_DS);
 430         return 0;
 431 }
 432
 433 static int load_aout_library(struct file *file)
 434 {
 435         struct inode *inode;
 436         unsigned long bss, start_addr, len, error;
 437         int retval;
 438         struct exec ex;
 439
 440         inode = file->f_path.dentry->d_inode;
 441
 442         retval = -ENOEXEC;
 443         error = kernel_read(file, 0, (char *) &ex, sizeof(ex));
 444         if (error != sizeof(ex))
 445                 goto out;
 446
 447         /* We come in here for the regular a.out style of shared libraries */
 448         if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != QMAGIC) || N_TRSIZE(ex) ||
 449             N_DRSIZE(ex) || ((ex.a_entry & 0xfff) && N_MAGIC(ex) == ZMAGIC) ||
 450             i_size_read(inode) <
 451             ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) {
 452                 goto out;
 453         }
 454
 455         if (N_FLAGS(ex))
 456                 goto out;
 457
 458         /* For  QMAGIC, the starting address is 0x20 into the page.  We mask
 459            this off to get the starting address for the page */
 460
 461         start_addr =  ex.a_entry & 0xfffff000;
 462
 463         if ((N_TXTOFF(ex) & ~PAGE_MASK) != 0) {
 464                 loff_t pos = N_TXTOFF(ex);
 465
 466 #ifdef WARN_OLD
 467                 static unsigned long error_time;
 468                 if (time_after(jiffies, error_time + 5*HZ)) {
 469                         printk(KERN_WARNING
 470                                "N_TXTOFF is not page aligned. Please convert "
 471                                "library: %s\n",
 472                                file->f_path.dentry->d_name.name);
 473                         error_time = jiffies;
 474                 }
 475 #endif
 476                 down_write(&current->mm->mmap_sem);
 477                 do_brk(start_addr, ex.a_text + ex.a_data + ex.a_bss);
 478                 up_write(&current->mm->mmap_sem);
 479
 480                 file->f_op->read(file, (char __user *)start_addr,
 481                         ex.a_text + ex.a_data, &pos);
 482                 flush_icache_range((unsigned long) start_addr,
 483                                    (unsigned long) start_addr + ex.a_text +
 484                                    ex.a_data);
 485
 486                 retval = 0;
 487                 goto out;
 488         }
 489         /* Now use mmap to map the library into memory. */
 490         down_write(&current->mm->mmap_sem);
 491         error = do_mmap(file, start_addr, ex.a_text + ex.a_data,
 492                         PROT_READ | PROT_WRITE | PROT_EXEC,
 493                         MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_32BIT,
 494                         N_TXTOFF(ex));
 495         up_write(&current->mm->mmap_sem);
 496         retval = error;
 497         if (error != start_addr)
 498                 goto out;
 499
 500         len = PAGE_ALIGN(ex.a_text + ex.a_data);
 501         bss = ex.a_text + ex.a_data + ex.a_bss;
 502         if (bss > len) {
 503                 down_write(&current->mm->mmap_sem);
 504                 error = do_brk(start_addr + len, bss - len);
 505                 up_write(&current->mm->mmap_sem);
 506                 retval = error;
 507                 if (error != start_addr + len)
 508                         goto out;
 509         }
 510         retval = 0;
 511 out:
 512         return retval;
 513 }
 514
 515 static int __init init_aout_binfmt(void)
 516 {
 517         return register_binfmt(&aout_format);
 518 }
 519
 520 static void __exit exit_aout_binfmt(void)
 521 {
 522         unregister_binfmt(&aout_format);
 523 }
 524
 525 module_init(init_aout_binfmt);
 526 module_exit(exit_aout_binfmt);
 527 MODULE_LICENSE("GPL");