linux/arch/x86/ia32/ia32_aout.c
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   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/slab.h>
  25#include <linux/binfmts.h>
  26#include <linux/personality.h>
  27#include <linux/init.h>
  28#include <linux/jiffies.h>
  29
  30#include <asm/system.h>
  31#include <asm/uaccess.h>
  32#include <asm/pgalloc.h>
  33#include <asm/cacheflush.h>
  34#include <asm/user32.h>
  35#include <asm/ia32.h>
  36
  37#undef WARN_OLD
  38#undef CORE_DUMP /* probably broken */
  39
  40static int load_aout_binary(struct linux_binprm *, struct pt_regs *regs);
  41static int load_aout_library(struct file *);
  42
  43#ifdef CORE_DUMP
  44static int aout_core_dump(long signr, struct pt_regs *regs, struct file *file,
  45                          unsigned long limit);
  46
  47/*
  48 * fill in the user structure for a core dump..
  49 */
  50static void dump_thread32(struct pt_regs *regs, struct user32 *dump)
  51{
  52        u32 fs, gs;
  53
  54/* changed the size calculations - should hopefully work better. lbt */
  55        dump->magic = CMAGIC;
  56        dump->start_code = 0;
  57        dump->start_stack = regs->sp & ~(PAGE_SIZE - 1);
  58        dump->u_tsize = ((unsigned long) current->mm->end_code) >> PAGE_SHIFT;
  59        dump->u_dsize = ((unsigned long)
  60                         (current->mm->brk + (PAGE_SIZE-1))) >> PAGE_SHIFT;
  61        dump->u_dsize -= dump->u_tsize;
  62        dump->u_ssize = 0;
  63        dump->u_debugreg[0] = current->thread.debugreg0;
  64        dump->u_debugreg[1] = current->thread.debugreg1;
  65        dump->u_debugreg[2] = current->thread.debugreg2;
  66        dump->u_debugreg[3] = current->thread.debugreg3;
  67        dump->u_debugreg[4] = 0;
  68        dump->u_debugreg[5] = 0;
  69        dump->u_debugreg[6] = current->thread.debugreg6;
  70        dump->u_debugreg[7] = current->thread.debugreg7;
  71
  72        if (dump->start_stack < 0xc0000000) {
  73                unsigned long tmp;
  74
  75                tmp = (unsigned long) (0xc0000000 - dump->start_stack);
  76                dump->u_ssize = tmp >> PAGE_SHIFT;
  77        }
  78
  79        dump->regs.bx = regs->bx;
  80        dump->regs.cx = regs->cx;
  81        dump->regs.dx = regs->dx;
  82        dump->regs.si = regs->si;
  83        dump->regs.di = regs->di;
  84        dump->regs.bp = regs->bp;
  85        dump->regs.ax = regs->ax;
  86        dump->regs.ds = current->thread.ds;
  87        dump->regs.es = current->thread.es;
  88        savesegment(fs, fs);
  89        dump->regs.fs = fs;
  90        savesegment(gs, gs);
  91        dump->regs.gs = gs;
  92        dump->regs.orig_ax = regs->orig_ax;
  93        dump->regs.ip = regs->ip;
  94        dump->regs.cs = regs->cs;
  95        dump->regs.flags = regs->flags;
  96        dump->regs.sp = regs->sp;
  97        dump->regs.ss = regs->ss;
  98
  99#if 1 /* FIXME */
 100        dump->u_fpvalid = 0;
 101#else
 102        dump->u_fpvalid = dump_fpu(regs, &dump->i387);
 103#endif
 104}
 105
 106#endif
 107
 108static struct linux_binfmt aout_format = {
 109        .module         = THIS_MODULE,
 110        .load_binary    = load_aout_binary,
 111        .load_shlib     = load_aout_library,
 112#ifdef CORE_DUMP
 113        .core_dump      = aout_core_dump,
 114#endif
 115        .min_coredump   = PAGE_SIZE
 116};
 117
 118static void set_brk(unsigned long start, unsigned long end)
 119{
 120        start = PAGE_ALIGN(start);
 121        end = PAGE_ALIGN(end);
 122        if (end <= start)
 123                return;
 124        down_write(&current->mm->mmap_sem);
 125        do_brk(start, end - start);
 126        up_write(&current->mm->mmap_sem);
 127}
 128
 129#ifdef CORE_DUMP
 130/*
 131 * These are the only things you should do on a core-file: use only these
 132 * macros to write out all the necessary info.
 133 */
 134
 135static int dump_write(struct file *file, const void *addr, int nr)
 136{
 137        return file->f_op->write(file, addr, nr, &file->f_pos) == nr;
 138}
 139
 140#define DUMP_WRITE(addr, nr)                         \
 141        if (!dump_write(file, (void *)(addr), (nr))) \
 142                goto end_coredump;
 143
 144#define DUMP_SEEK(offset)                                               \
 145        if (file->f_op->llseek) {                                       \
 146                if (file->f_op->llseek(file, (offset), 0) != (offset))  \
 147                        goto end_coredump;                              \
 148        } else                                                          \
 149                file->f_pos = (offset)
 150
 151#define START_DATA()    (u.u_tsize << PAGE_SHIFT)
 152#define START_STACK(u)  (u.start_stack)
 153
 154/*
 155 * Routine writes a core dump image in the current directory.
 156 * Currently only a stub-function.
 157 *
 158 * Note that setuid/setgid files won't make a core-dump if the uid/gid
 159 * changed due to the set[u|g]id. It's enforced by the "current->mm->dumpable"
 160 * field, which also makes sure the core-dumps won't be recursive if the
 161 * dumping of the process results in another error..
 162 */
 163
 164static int aout_core_dump(long signr, struct pt_regs *regs, struct file *file,
 165                          unsigned long limit)
 166{
 167        mm_segment_t fs;
 168        int has_dumped = 0;
 169        unsigned long dump_start, dump_size;
 170        struct user32 dump;
 171
 172        fs = get_fs();
 173        set_fs(KERNEL_DS);
 174        has_dumped = 1;
 175        current->flags |= PF_DUMPCORE;
 176        strncpy(dump.u_comm, current->comm, sizeof(current->comm));
 177        dump.u_ar0 = offsetof(struct user32, regs);
 178        dump.signal = signr;
 179        dump_thread32(regs, &dump);
 180
 181        /*
 182         * If the size of the dump file exceeds the rlimit, then see
 183         * what would happen if we wrote the stack, but not the data
 184         * area.
 185         */
 186        if ((dump.u_dsize + dump.u_ssize + 1) * PAGE_SIZE > limit)
 187                dump.u_dsize = 0;
 188
 189        /* Make sure we have enough room to write the stack and data areas. */
 190        if ((dump.u_ssize + 1) * PAGE_SIZE > limit)
 191                dump.u_ssize = 0;
 192
 193        /* make sure we actually have a data and stack area to dump */
 194        set_fs(USER_DS);
 195        if (!access_ok(VERIFY_READ, (void *) (unsigned long)START_DATA(dump),
 196                       dump.u_dsize << PAGE_SHIFT))
 197                dump.u_dsize = 0;
 198        if (!access_ok(VERIFY_READ, (void *) (unsigned long)START_STACK(dump),
 199                       dump.u_ssize << PAGE_SHIFT))
 200                dump.u_ssize = 0;
 201
 202        set_fs(KERNEL_DS);
 203        /* struct user */
 204        DUMP_WRITE(&dump, sizeof(dump));
 205        /* Now dump all of the user data.  Include malloced stuff as well */
 206        DUMP_SEEK(PAGE_SIZE);
 207        /* now we start writing out the user space info */
 208        set_fs(USER_DS);
 209        /* Dump the data area */
 210        if (dump.u_dsize != 0) {
 211                dump_start = START_DATA(dump);
 212                dump_size = dump.u_dsize << PAGE_SHIFT;
 213                DUMP_WRITE(dump_start, dump_size);
 214        }
 215        /* Now prepare to dump the stack area */
 216        if (dump.u_ssize != 0) {
 217                dump_start = START_STACK(dump);
 218                dump_size = dump.u_ssize << PAGE_SHIFT;
 219                DUMP_WRITE(dump_start, dump_size);
 220        }
 221        /*
 222         * Finally dump the task struct.  Not be used by gdb, but
 223         * could be useful
 224         */
 225        set_fs(KERNEL_DS);
 226        DUMP_WRITE(current, sizeof(*current));
 227end_coredump:
 228        set_fs(fs);
 229        return has_dumped;
 230}
 231#endif
 232
 233/*
 234 * create_aout_tables() parses the env- and arg-strings in new user
 235 * memory and creates the pointer tables from them, and puts their
 236 * addresses on the "stack", returning the new stack pointer value.
 237 */
 238static u32 __user *create_aout_tables(char __user *p, struct linux_binprm *bprm)
 239{
 240        u32 __user *argv, *envp, *sp;
 241        int argc = bprm->argc, envc = bprm->envc;
 242
 243        sp = (u32 __user *) ((-(unsigned long)sizeof(u32)) & (unsigned long) p);
 244        sp -= envc+1;
 245        envp = sp;
 246        sp -= argc+1;
 247        argv = sp;
 248        put_user((unsigned long) envp, --sp);
 249        put_user((unsigned long) argv, --sp);
 250        put_user(argc, --sp);
 251        current->mm->arg_start = (unsigned long) p;
 252        while (argc-- > 0) {
 253                char c;
 254
 255                put_user((u32)(unsigned long)p, argv++);
 256                do {
 257                        get_user(c, p++);
 258                } while (c);
 259        }
 260        put_user(0, argv);
 261        current->mm->arg_end = current->mm->env_start = (unsigned long) p;
 262        while (envc-- > 0) {
 263                char c;
 264
 265                put_user((u32)(unsigned long)p, envp++);
 266                do {
 267                        get_user(c, p++);
 268                } while (c);
 269        }
 270        put_user(0, envp);
 271        current->mm->env_end = (unsigned long) p;
 272        return sp;
 273}
 274
 275/*
 276 * These are the functions used to load a.out style executables and shared
 277 * libraries.  There is no binary dependent code anywhere else.
 278 */
 279static int load_aout_binary(struct linux_binprm *bprm, struct pt_regs *regs)
 280{
 281        unsigned long error, fd_offset, rlim;
 282        struct exec ex;
 283        int retval;
 284
 285        ex = *((struct exec *) bprm->buf);              /* exec-header */
 286        if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != OMAGIC &&
 287             N_MAGIC(ex) != QMAGIC && N_MAGIC(ex) != NMAGIC) ||
 288            N_TRSIZE(ex) || N_DRSIZE(ex) ||
 289            i_size_read(bprm->file->f_path.dentry->d_inode) <
 290            ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) {
 291                return -ENOEXEC;
 292        }
 293
 294        fd_offset = N_TXTOFF(ex);
 295
 296        /* Check initial limits. This avoids letting people circumvent
 297         * size limits imposed on them by creating programs with large
 298         * arrays in the data or bss.
 299         */
 300        rlim = current->signal->rlim[RLIMIT_DATA].rlim_cur;
 301        if (rlim >= RLIM_INFINITY)
 302                rlim = ~0;
 303        if (ex.a_data + ex.a_bss > rlim)
 304                return -ENOMEM;
 305
 306        /* Flush all traces of the currently running executable */
 307        retval = flush_old_exec(bprm);
 308        if (retval)
 309                return retval;
 310
 311        regs->cs = __USER32_CS;
 312        regs->r8 = regs->r9 = regs->r10 = regs->r11 = regs->r12 =
 313                regs->r13 = regs->r14 = regs->r15 = 0;
 314
 315        /* OK, This is the point of no return */
 316        set_personality(PER_LINUX);
 317        set_thread_flag(TIF_IA32);
 318        clear_thread_flag(TIF_ABI_PENDING);
 319
 320        current->mm->end_code = ex.a_text +
 321                (current->mm->start_code = N_TXTADDR(ex));
 322        current->mm->end_data = ex.a_data +
 323                (current->mm->start_data = N_DATADDR(ex));
 324        current->mm->brk = ex.a_bss +
 325                (current->mm->start_brk = N_BSSADDR(ex));
 326        current->mm->free_area_cache = TASK_UNMAPPED_BASE;
 327        current->mm->cached_hole_size = 0;
 328
 329        current->mm->mmap = NULL;
 330        compute_creds(bprm);
 331        current->flags &= ~PF_FORKNOEXEC;
 332
 333        if (N_MAGIC(ex) == OMAGIC) {
 334                unsigned long text_addr, map_size;
 335                loff_t pos;
 336
 337                text_addr = N_TXTADDR(ex);
 338
 339                pos = 32;
 340                map_size = ex.a_text+ex.a_data;
 341
 342                down_write(&current->mm->mmap_sem);
 343                error = do_brk(text_addr & PAGE_MASK, map_size);
 344                up_write(&current->mm->mmap_sem);
 345
 346                if (error != (text_addr & PAGE_MASK)) {
 347                        send_sig(SIGKILL, current, 0);
 348                        return error;
 349                }
 350
 351                error = bprm->file->f_op->read(bprm->file,
 352                         (char __user *)text_addr,
 353                          ex.a_text+ex.a_data, &pos);
 354                if ((signed long)error < 0) {
 355                        send_sig(SIGKILL, current, 0);
 356                        return error;
 357                }
 358
 359                flush_icache_range(text_addr, text_addr+ex.a_text+ex.a_data);
 360        } else {
 361#ifdef WARN_OLD
 362                static unsigned long error_time, error_time2;
 363                if ((ex.a_text & 0xfff || ex.a_data & 0xfff) &&
 364                    (N_MAGIC(ex) != NMAGIC) &&
 365                                time_after(jiffies, error_time2 + 5*HZ)) {
 366                        printk(KERN_NOTICE "executable not page aligned\n");
 367                        error_time2 = jiffies;
 368                }
 369
 370                if ((fd_offset & ~PAGE_MASK) != 0 &&
 371                            time_after(jiffies, error_time + 5*HZ)) {
 372                        printk(KERN_WARNING
 373                               "fd_offset is not page aligned. Please convert "
 374                               "program: %s\n",
 375                               bprm->file->f_path.dentry->d_name.name);
 376                        error_time = jiffies;
 377                }
 378#endif
 379
 380                if (!bprm->file->f_op->mmap || (fd_offset & ~PAGE_MASK) != 0) {
 381                        loff_t pos = fd_offset;
 382
 383                        down_write(&current->mm->mmap_sem);
 384                        do_brk(N_TXTADDR(ex), ex.a_text+ex.a_data);
 385                        up_write(&current->mm->mmap_sem);
 386                        bprm->file->f_op->read(bprm->file,
 387                                        (char __user *)N_TXTADDR(ex),
 388                                        ex.a_text+ex.a_data, &pos);
 389                        flush_icache_range((unsigned long) N_TXTADDR(ex),
 390                                           (unsigned long) N_TXTADDR(ex) +
 391                                           ex.a_text+ex.a_data);
 392                        goto beyond_if;
 393                }
 394
 395                down_write(&current->mm->mmap_sem);
 396                error = do_mmap(bprm->file, N_TXTADDR(ex), ex.a_text,
 397                                PROT_READ | PROT_EXEC,
 398                                MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE |
 399                                MAP_EXECUTABLE | MAP_32BIT,
 400                                fd_offset);
 401                up_write(&current->mm->mmap_sem);
 402
 403                if (error != N_TXTADDR(ex)) {
 404                        send_sig(SIGKILL, current, 0);
 405                        return error;
 406                }
 407
 408                down_write(&current->mm->mmap_sem);
 409                error = do_mmap(bprm->file, N_DATADDR(ex), ex.a_data,
 410                                PROT_READ | PROT_WRITE | PROT_EXEC,
 411                                MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE |
 412                                MAP_EXECUTABLE | MAP_32BIT,
 413                                fd_offset + ex.a_text);
 414                up_write(&current->mm->mmap_sem);
 415                if (error != N_DATADDR(ex)) {
 416                        send_sig(SIGKILL, current, 0);
 417                        return error;
 418                }
 419        }
 420beyond_if:
 421        set_binfmt(&aout_format);
 422
 423        set_brk(current->mm->start_brk, current->mm->brk);
 424
 425        retval = setup_arg_pages(bprm, IA32_STACK_TOP, EXSTACK_DEFAULT);
 426        if (retval < 0) {
 427                /* Someone check-me: is this error path enough? */
 428                send_sig(SIGKILL, current, 0);
 429                return retval;
 430        }
 431
 432        current->mm->start_stack =
 433                (unsigned long)create_aout_tables((char __user *)bprm->p, bprm);
 434        /* start thread */
 435        loadsegment(fs, 0);
 436        loadsegment(ds, __USER32_DS);
 437        loadsegment(es, __USER32_DS);
 438        load_gs_index(0);
 439        (regs)->ip = ex.a_entry;
 440        (regs)->sp = current->mm->start_stack;
 441        (regs)->flags = 0x200;
 442        (regs)->cs = __USER32_CS;
 443        (regs)->ss = __USER32_DS;
 444        regs->r8 = regs->r9 = regs->r10 = regs->r11 =
 445        regs->r12 = regs->r13 = regs->r14 = regs->r15 = 0;
 446        set_fs(USER_DS);
 447        return 0;
 448}
 449
 450static int load_aout_library(struct file *file)
 451{
 452        struct inode *inode;
 453        unsigned long bss, start_addr, len, error;
 454        int retval;
 455        struct exec ex;
 456
 457        inode = file->f_path.dentry->d_inode;
 458
 459        retval = -ENOEXEC;
 460        error = kernel_read(file, 0, (char *) &ex, sizeof(ex));
 461        if (error != sizeof(ex))
 462                goto out;
 463
 464        /* We come in here for the regular a.out style of shared libraries */
 465        if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != QMAGIC) || N_TRSIZE(ex) ||
 466            N_DRSIZE(ex) || ((ex.a_entry & 0xfff) && N_MAGIC(ex) == ZMAGIC) ||
 467            i_size_read(inode) <
 468            ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) {
 469                goto out;
 470        }
 471
 472        if (N_FLAGS(ex))
 473                goto out;
 474
 475        /* For  QMAGIC, the starting address is 0x20 into the page.  We mask
 476           this off to get the starting address for the page */
 477
 478        start_addr =  ex.a_entry & 0xfffff000;
 479
 480        if ((N_TXTOFF(ex) & ~PAGE_MASK) != 0) {
 481                loff_t pos = N_TXTOFF(ex);
 482
 483#ifdef WARN_OLD
 484                static unsigned long error_time;
 485                if (time_after(jiffies, error_time + 5*HZ)) {
 486                        printk(KERN_WARNING
 487                               "N_TXTOFF is not page aligned. Please convert "
 488                               "library: %s\n",
 489                               file->f_path.dentry->d_name.name);
 490                        error_time = jiffies;
 491                }
 492#endif
 493                down_write(&current->mm->mmap_sem);
 494                do_brk(start_addr, ex.a_text + ex.a_data + ex.a_bss);
 495                up_write(&current->mm->mmap_sem);
 496
 497                file->f_op->read(file, (char __user *)start_addr,
 498                        ex.a_text + ex.a_data, &pos);
 499                flush_icache_range((unsigned long) start_addr,
 500                                   (unsigned long) start_addr + ex.a_text +
 501                                   ex.a_data);
 502
 503                retval = 0;
 504                goto out;
 505        }
 506        /* Now use mmap to map the library into memory. */
 507        down_write(&current->mm->mmap_sem);
 508        error = do_mmap(file, start_addr, ex.a_text + ex.a_data,
 509                        PROT_READ | PROT_WRITE | PROT_EXEC,
 510                        MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_32BIT,
 511                        N_TXTOFF(ex));
 512        up_write(&current->mm->mmap_sem);
 513        retval = error;
 514        if (error != start_addr)
 515                goto out;
 516
 517        len = PAGE_ALIGN(ex.a_text + ex.a_data);
 518        bss = ex.a_text + ex.a_data + ex.a_bss;
 519        if (bss > len) {
 520                down_write(&current->mm->mmap_sem);
 521                error = do_brk(start_addr + len, bss - len);
 522                up_write(&current->mm->mmap_sem);
 523                retval = error;
 524                if (error != start_addr + len)
 525                        goto out;
 526        }
 527        retval = 0;
 528out:
 529        return retval;
 530}
 531
 532static int __init init_aout_binfmt(void)
 533{
 534        return register_binfmt(&aout_format);
 535}
 536
 537static void __exit exit_aout_binfmt(void)
 538{
 539        unregister_binfmt(&aout_format);
 540}
 541
 542module_init(init_aout_binfmt);
 543module_exit(exit_aout_binfmt);
 544MODULE_LICENSE("GPL");
 545