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