sys/kern/link_aout.c

   1 /*-
   2  * Copyright (c) 1997 Doug Rabson
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  *
  14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  24  * SUCH DAMAGE.
  25  *
  26  * $FreeBSD: src/sys/kern/link_aout.c,v 1.26 1999/12/24 15:33:36 bde Exp $
  27  * $DragonFly: src/sys/kern/link_aout.c,v 1.24 2008/02/06 22:37:46 nth Exp $
  28  */
  29
  30 #define FREEBSD_AOUT    1
  31
  32 #include <sys/param.h>
  33 #include <sys/kernel.h>
  34 #include <sys/systm.h>
  35 #include <sys/types.h>
  36 #include <sys/malloc.h>
  37 #include <sys/proc.h>
  38 #include <sys/nlookup.h>
  39 #include <sys/fcntl.h>
  40 #include <sys/vnode.h>
  41 #include <sys/linker.h>
  42
  43 #include <vm/vm_zone.h>
  44
  45 #ifndef __ELF__
  46 #include <vm/vm.h>
  47 #include <vm/pmap.h>
  48 #include <machine/vmparam.h>
  49 #endif
  50
  51 #include <machine/exec.h>
  52 #include <sys/imgact_aout.h>
  53 #include <machine/reloc.h>
  54 #define _AOUT_INCLUDE_
  55 #include <sys/nlist_aout.h>
  56 #include <sys/link_aout.h>
  57
  58 static int              link_aout_load_module(const char*, linker_file_t*);
  59
  60 static int              link_aout_load_file(const char*, linker_file_t*);
  61
  62 static int              link_aout_lookup_symbol(linker_file_t, const char*,
  63                                                 c_linker_sym_t*);
  64 static int              link_aout_symbol_values(linker_file_t file, c_linker_sym_t sym,
  65                                                 linker_symval_t* symval);
  66 static int              link_aout_search_symbol(linker_file_t lf, caddr_t value,
  67                                                 c_linker_sym_t* sym, long* diffp);
  68 static void             link_aout_unload_file(linker_file_t);
  69 static void             link_aout_unload_module(linker_file_t);
  70 static int              link_aout_lookup_set(linker_file_t lf, const char *name,
  71                                 void ***startp, void ***stopp, int *countp);
  72
  73 static struct linker_class_ops link_aout_class_ops = {
  74     link_aout_load_module,
  75 };
  76
  77 static struct linker_file_ops link_aout_file_ops = {
  78     link_aout_lookup_symbol,
  79     link_aout_symbol_values,
  80     link_aout_search_symbol,
  81     link_aout_unload_file,
  82     link_aout_lookup_set
  83 };
  84 static struct linker_file_ops link_aout_module_ops = {
  85     link_aout_lookup_symbol,
  86     link_aout_symbol_values,
  87     link_aout_search_symbol,
  88     link_aout_unload_module,
  89     link_aout_lookup_set
  90 };
  91
  92 typedef struct aout_file {
  93     char*               address;        /* Load address */
  94     struct _dynamic*    dynamic;        /* Symbol table etc. */
  95 } *aout_file_t;
  96
  97 static int              load_dependancies(linker_file_t lf);
  98 static int              relocate_file(linker_file_t lf);
  99
 100 /*
 101  * The kernel symbol table starts here.
 102  */
 103 extern struct _dynamic _DYNAMIC;
 104
 105 static void
 106 link_aout_init(void* arg)
 107 {
 108 #ifndef __ELF__
 109     struct _dynamic* dp = &_DYNAMIC;
 110 #endif
 111
 112     linker_add_class("a.out", NULL, &link_aout_class_ops);
 113
 114 #ifndef __ELF__
 115     if (dp) {
 116         aout_file_t af;
 117
 118         af = kmalloc(sizeof(struct aout_file), M_LINKER, M_NOWAIT | M_ZERO);
 119         if (af == NULL)
 120             panic("link_aout_init: Can't create linker structures for kernel");
 121
 122         af->address = 0;
 123         af->dynamic = dp;
 124         linker_kernel_file =
 125             linker_make_file(kernelname, af, &link_aout_file_ops);
 126         if (linker_kernel_file == NULL)
 127             panic("link_aout_init: Can't create linker structures for kernel");
 128         linker_kernel_file->address = (caddr_t) KERNBASE;
 129         linker_kernel_file->size = -(long)linker_kernel_file->address;
 130         linker_current_file = linker_kernel_file;
 131         linker_kernel_file->flags |= LINKER_FILE_LINKED;
 132     }
 133 #endif
 134 }
 135
 136 SYSINIT(link_aout, SI_BOOT2_KLD, SI_ORDER_THIRD, link_aout_init, 0);
 137
 138 static int
 139 link_aout_load_module(const char* filename, linker_file_t* result)
 140 {
 141     caddr_t             modptr, baseptr;
 142     char                *type;
 143     struct exec         *ehdr;
 144     aout_file_t         af;
 145     linker_file_t       lf;
 146     int                 error;
 147
 148     /* Look to see if we have the module preloaded. */
 149     if ((modptr = preload_search_by_name(filename)) == NULL)
 150         return(link_aout_load_file(filename, result));
 151
 152     /* It's preloaded, check we can handle it and collect information. */
 153     if (((type = (char *)preload_search_info(modptr, MODINFO_TYPE)) == NULL) ||
 154         strcmp(type, "a.out module") ||
 155         ((baseptr = preload_search_info(modptr, MODINFO_ADDR)) == NULL) ||
 156         ((ehdr = (struct exec *)preload_search_info(modptr, MODINFO_METADATA | MODINFOMD_AOUTEXEC)) == NULL))
 157         return(0);                      /* we can't handle this */
 158
 159     /* Looks like we can handle this one */
 160     af = kmalloc(sizeof(struct aout_file), M_LINKER, M_WAITOK | M_ZERO);
 161     af->address = baseptr;
 162
 163     /* Assume _DYNAMIC is the first data item. */
 164     af->dynamic = (struct _dynamic*)(af->address + ehdr->a_text);
 165     if (af->dynamic->d_version != LD_VERSION_BSD) {
 166         kfree(af, M_LINKER);
 167         return(0);                      /* we can't handle this */
 168     }
 169     af->dynamic->d_un.d_sdt = (struct section_dispatch_table *)
 170         ((char *)af->dynamic->d_un.d_sdt + (vm_offset_t)af->address);
 171
 172     /* Register with kld */
 173     lf = linker_make_file(filename, af, &link_aout_module_ops);
 174     if (lf == NULL) {
 175         kfree(af, M_LINKER);
 176         return(ENOMEM);
 177     }
 178     lf->address = af->address;
 179     lf->size = ehdr->a_text + ehdr->a_data + ehdr->a_bss;
 180
 181     /* Try to load dependancies */
 182     if (((error = load_dependancies(lf)) != 0) ||
 183         ((error = relocate_file(lf)) != 0)) {
 184         linker_file_unload(lf);
 185         return(error);
 186     }
 187     lf->flags |= LINKER_FILE_LINKED;
 188     *result = lf;
 189     return(0);
 190 }
 191
 192 static int
 193 link_aout_load_file(const char* filename, linker_file_t* result)
 194 {
 195     struct nlookupdata nd;
 196     struct thread *td = curthread;
 197     struct proc *p = td->td_proc;
 198     struct vnode *vp;
 199     int error = 0;
 200     int resid;
 201     struct exec header;
 202     aout_file_t af;
 203     linker_file_t lf;
 204     char *pathname;
 205
 206     KKASSERT(p != NULL);
 207
 208     if (p->p_ucred == NULL) {
 209         kprintf("link_aout_load_file: cannot load '%s' from filesystem"
 210                 " this early\n", filename);
 211         return ENOENT;
 212     }
 213
 214     pathname = linker_search_path(filename);
 215     if (pathname == NULL)
 216         return ENOENT;
 217     error = nlookup_init(&nd, pathname, UIO_SYSSPACE, NLC_FOLLOW|NLC_LOCKVP);
 218     if (error == 0)
 219         error = vn_open(&nd, NULL, FREAD, 0);
 220     kfree(pathname, M_LINKER);
 221     if (error) {
 222         nlookup_done(&nd);
 223         return error;
 224     }
 225     vp = nd.nl_open_vp;
 226     nd.nl_open_vp = NULL;
 227     nlookup_done(&nd);
 228
 229     /*
 230      * Read the a.out header from the file.
 231      */
 232     error = vn_rdwr(UIO_READ, vp, (void*) &header, sizeof header, 0,
 233                     UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid);
 234     if (error)
 235         goto out;
 236
 237     if (N_BADMAG(header) || !(N_GETFLAG(header) & EX_DYNAMIC))
 238         goto out;
 239
 240     /*
 241      * We have an a.out file, so make some space to read it in.
 242      */
 243     af = kmalloc(sizeof(struct aout_file), M_LINKER, M_WAITOK | M_ZERO);
 244     af->address = kmalloc(header.a_text + header.a_data + header.a_bss,
 245                          M_LINKER, M_WAITOK);
 246
 247     /*
 248      * Read the text and data sections and zero the bss.
 249      */
 250     error = vn_rdwr(UIO_READ, vp, (void*) af->address,
 251                     header.a_text + header.a_data, 0,
 252                     UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid);
 253     if (error)
 254         goto out;
 255     bzero(af->address + header.a_text + header.a_data, header.a_bss);
 256
 257     /*
 258      * Assume _DYNAMIC is the first data item.
 259      */
 260     af->dynamic = (struct _dynamic*) (af->address + header.a_text);
 261     if (af->dynamic->d_version != LD_VERSION_BSD) {
 262         kfree(af->address, M_LINKER);
 263         kfree(af, M_LINKER);
 264         goto out;
 265     }
 266     af->dynamic->d_un.d_sdt = (struct section_dispatch_table *)
 267         ((char *)af->dynamic->d_un.d_sdt + (vm_offset_t)af->address);
 268
 269     lf = linker_make_file(filename, af, &link_aout_file_ops);
 270     if (lf == NULL) {
 271         kfree(af->address, M_LINKER);
 272         kfree(af, M_LINKER);
 273         error = ENOMEM;
 274         goto out;
 275     }
 276     lf->address = af->address;
 277     lf->size = header.a_text + header.a_data + header.a_bss;
 278
 279     if ((error = load_dependancies(lf)) != 0
 280         || (error = relocate_file(lf)) != 0) {
 281         linker_file_unload(lf);
 282         goto out;
 283     }
 284
 285     lf->flags |= LINKER_FILE_LINKED;
 286     *result = lf;
 287
 288 out:
 289     vn_unlock(vp);
 290     vn_close(vp, FREAD);
 291
 292     return error;
 293 }
 294
 295 static void
 296 link_aout_unload_file(linker_file_t file)
 297 {
 298     aout_file_t af = file->priv;
 299
 300     if (af) {
 301         if (af->address)
 302             kfree(af->address, M_LINKER);
 303         kfree(af, M_LINKER);
 304     }
 305 }
 306
 307 static void
 308 link_aout_unload_module(linker_file_t file)
 309 {
 310     aout_file_t af = file->priv;
 311
 312     if (af)
 313         kfree(af, M_LINKER);
 314     if (file->filename)
 315         preload_delete_name(file->filename);
 316 }
 317
 318 #define AOUT_RELOC(af, type, off) (type*) ((af)->address + (off))
 319
 320 static int
 321 load_dependancies(linker_file_t lf)
 322 {
 323     aout_file_t af = lf->priv;
 324     linker_file_t lfdep;
 325     long off;
 326     struct sod* sodp;
 327     char* name;
 328     char* filename = 0;
 329     int error = 0;
 330
 331     /*
 332      * All files are dependant on /kernel.
 333      */
 334     if (linker_kernel_file) {
 335         linker_kernel_file->refs++;
 336         linker_file_add_dependancy(lf, linker_kernel_file);
 337     }
 338
 339     off = LD_NEED(af->dynamic);
 340
 341     /*
 342      * Load the dependancies.
 343      */
 344     while (off != 0) {
 345         sodp = AOUT_RELOC(af, struct sod, off);
 346         name = AOUT_RELOC(af, char, sodp->sod_name);
 347
 348         error = linker_load_file(name, &lfdep);
 349         if (error)
 350             goto out;
 351         linker_file_add_dependancy(lf, lfdep);
 352         off = sodp->sod_next;
 353     }
 354
 355 out:
 356     if (filename)
 357         kfree(filename, M_TEMP);
 358     return error;
 359 }
 360
 361 /*
 362  * XXX i386 dependant.
 363  */
 364 static long
 365 read_relocation(struct relocation_info* r, char* addr)
 366 {
 367     int length = r->r_length;
 368     if (length == 0)
 369         return *(u_char*) addr;
 370     else if (length == 1)
 371         return *(u_short*) addr;
 372     else if (length == 2)
 373         return *(u_int*) addr;
 374     else
 375         kprintf("link_aout: unsupported relocation size %d\n", r->r_length);
 376     return 0;
 377 }
 378
 379 static void
 380 write_relocation(struct relocation_info* r, char* addr, long value)
 381 {
 382     int length = r->r_length;
 383     if (length == 0)
 384         *(u_char*) addr = value;
 385     else if (length == 1)
 386         *(u_short*) addr = value;
 387     else if (length == 2)
 388         *(u_int*) addr = value;
 389     else
 390         kprintf("link_aout: unsupported relocation size %d\n", r->r_length);
 391 }
 392
 393 static int
 394 relocate_file(linker_file_t lf)
 395 {
 396     aout_file_t af = lf->priv;
 397     struct relocation_info* rel;
 398     struct relocation_info* erel;
 399     struct relocation_info* r;
 400     struct nzlist* symbolbase;
 401     char* stringbase;
 402     struct nzlist* np;
 403     char* sym;
 404     long relocation;
 405
 406     rel = AOUT_RELOC(af, struct relocation_info, LD_REL(af->dynamic));
 407     erel = AOUT_RELOC(af, struct relocation_info,
 408                       LD_REL(af->dynamic) + LD_RELSZ(af->dynamic));
 409     symbolbase = AOUT_RELOC(af, struct nzlist, LD_SYMBOL(af->dynamic));
 410     stringbase = AOUT_RELOC(af, char, LD_STRINGS(af->dynamic));
 411
 412     for (r = rel; r < erel; r++) {
 413         char* addr;
 414
 415         if (r->r_address == 0)
 416             break;
 417
 418         addr = AOUT_RELOC(af, char, r->r_address);
 419         if (r->r_extern) {
 420             np = &symbolbase[r->r_symbolnum];
 421             sym = &stringbase[np->nz_strx];
 422
 423             if (sym[0] != '_') {
 424                 kprintf("link_aout: bad symbol name %s\n", sym);
 425                 kprintf("link_aout: symbol %s not found\n", sym);
 426                 return ENOENT;
 427             } else {
 428                 if (linker_file_lookup_symbol(lf, sym + 1,
 429                     (np->nz_type != (N_SETV+N_EXT)), (caddr_t *)&relocation)) {
 430                         kprintf("link_aout: symbol %s not found\n", sym);
 431                         return ENOENT;
 432                 }
 433             }
 434
 435             relocation += read_relocation(r, addr);
 436
 437             if (r->r_jmptable) {
 438                 kprintf("link_aout: can't cope with jump table relocations\n");
 439                 continue;
 440             }
 441
 442             if (r->r_pcrel)
 443                 relocation -= (intptr_t) af->address;
 444
 445             if (r->r_copy) {
 446                 kprintf("link_aout: can't cope with copy relocations\n");
 447                 continue;
 448             }
 449
 450             write_relocation(r, addr, relocation);
 451         } else {
 452             write_relocation(r, addr,
 453                              (intptr_t)(read_relocation(r, addr) + af->address));
 454         }
 455
 456     }
 457
 458     return 0;
 459 }
 460
 461 static long
 462 symbol_hash_value(aout_file_t af, const char* name)
 463 {
 464     long hashval;
 465     const char* p;
 466
 467     hashval = '_';              /* fake a starting '_' for C symbols */
 468     for (p = name; *p; p++)
 469         hashval = (hashval << 1) + *p;
 470
 471     return (hashval & 0x7fffffff) % LD_BUCKETS(af->dynamic);
 472 }
 473
 474 int
 475 link_aout_lookup_symbol(linker_file_t file, const char* name,
 476                         c_linker_sym_t* sym)
 477 {
 478     aout_file_t af = file->priv;
 479     long hashval;
 480     struct rrs_hash* hashbase;
 481     struct nzlist* symbolbase;
 482     char* stringbase;
 483     struct rrs_hash* hp;
 484     struct nzlist* np;
 485     char* cp;
 486
 487     if (LD_BUCKETS(af->dynamic) == 0)
 488         return 0;
 489
 490     hashbase = AOUT_RELOC(af, struct rrs_hash, LD_HASH(af->dynamic));
 491     symbolbase = AOUT_RELOC(af, struct nzlist, LD_SYMBOL(af->dynamic));
 492     stringbase = AOUT_RELOC(af, char, LD_STRINGS(af->dynamic));
 493
 494 restart:
 495     hashval = symbol_hash_value(af, name);
 496     hp = &hashbase[hashval];
 497     if (hp->rh_symbolnum == -1)
 498         return ENOENT;
 499
 500     while (hp) {
 501         np = (struct nzlist *) &symbolbase[hp->rh_symbolnum];
 502         cp = stringbase + np->nz_strx;
 503         /*
 504          * Note: we fake the leading '_' for C symbols.
 505          */
 506         if (cp[0] == '_' && !strcmp(cp + 1, name))
 507             break;
 508
 509         if (hp->rh_next == 0)
 510             hp = NULL;
 511         else
 512             hp = &hashbase[hp->rh_next];
 513     }
 514
 515     if (hp == NULL)
 516         /*
 517          * Not found.
 518          */
 519         return ENOENT;
 520
 521     /*
 522      * Check for an aliased symbol, whatever that is.
 523      */
 524     if (np->nz_type == N_INDR+N_EXT) {
 525         name = stringbase + (++np)->nz_strx + 1; /* +1 for '_' */
 526         goto restart;
 527     }
 528
 529     /*
 530      * Check this is an actual definition of the symbol.
 531      */
 532     if (np->nz_value == 0)
 533         return ENOENT;
 534
 535     if (np->nz_type == N_UNDF+N_EXT && np->nz_value != 0) {
 536         if (np->nz_other == AUX_FUNC)
 537             /* weak function */
 538             return ENOENT;
 539     }
 540
 541     *sym = (linker_sym_t) np;
 542
 543     return 0;
 544 }
 545
 546
 547 static int
 548 link_aout_symbol_values(linker_file_t file, c_linker_sym_t sym,
 549                         linker_symval_t* symval)
 550 {
 551     aout_file_t af = file->priv;
 552     const struct nzlist* np = (const struct nzlist*) sym;
 553     char* stringbase;
 554     long numsym = LD_STABSZ(af->dynamic) / sizeof(struct nzlist);
 555     struct nzlist *symbase;
 556
 557     /* Is it one of ours?  It could be another module... */
 558     symbase = AOUT_RELOC(af, struct nzlist, LD_SYMBOL(af->dynamic));
 559     if (np < symbase)
 560         return ENOENT;
 561     if ((np - symbase) > numsym)
 562         return ENOENT;
 563
 564     stringbase = AOUT_RELOC(af, char, LD_STRINGS(af->dynamic));
 565
 566     symval->name = stringbase + np->nz_strx + 1; /* +1 for '_' */
 567     if (np->nz_type == N_UNDF+N_EXT && np->nz_value != 0) {
 568         symval->value = 0;
 569         symval->size = np->nz_value;
 570     } else {
 571         symval->value = AOUT_RELOC(af, char, np->nz_value);
 572         symval->size = np->nz_size;
 573     }
 574     return 0;
 575 }
 576
 577 static int
 578 link_aout_search_symbol(linker_file_t lf, caddr_t value,
 579                         c_linker_sym_t* sym, long* diffp)
 580 {
 581         aout_file_t af = lf->priv;
 582         u_long off = (uintptr_t) (void *) value;
 583         u_long diff = off;
 584         u_long sp_nz_value;
 585         struct nzlist* sp;
 586         struct nzlist* ep;
 587         struct nzlist* best = 0;
 588
 589         for (sp = AOUT_RELOC(af, struct nzlist, LD_SYMBOL(af->dynamic)),
 590                  ep = (struct nzlist *) ((caddr_t) sp + LD_STABSZ(af->dynamic));
 591              sp < ep; sp++) {
 592                 if (sp->nz_name == 0)
 593                         continue;
 594                 sp_nz_value = sp->nz_value + (uintptr_t) (void *) af->address;
 595                 if (off >= sp_nz_value) {
 596                         if (off - sp_nz_value < diff) {
 597                                 diff = off - sp_nz_value;
 598                                 best = sp;
 599                                 if (diff == 0)
 600                                         break;
 601                         } else if (off - sp_nz_value == diff) {
 602                                 best = sp;
 603                         }
 604                 }
 605         }
 606         if (best == 0)
 607                 *diffp = off;
 608         else
 609                 *diffp = diff;
 610         *sym = (linker_sym_t) best;
 611
 612         return 0;
 613 }
 614
 615 /*
 616  * Look up a linker set on an a.out + gnu LD system.
 617  */
 618
 619 struct generic_linker_set {
 620         int     ls_length;
 621         void    *ls_items[1];
 622 };
 623
 624 static int
 625 link_aout_lookup_set(linker_file_t lf, const char *name,
 626                     void ***startp, void ***stopp, int *countp)
 627 {
 628         c_linker_sym_t sym;
 629         linker_symval_t symval;
 630         void **start, **stop;
 631         int error, count;
 632         struct generic_linker_set *setp;
 633
 634         error = link_aout_lookup_symbol(lf, name, &sym);
 635         if (error)
 636                return error;
 637         link_aout_symbol_values(lf, sym, &symval);
 638         if (symval.value == 0)
 639                return ESRCH;
 640         setp = (struct generic_linker_set *)symval.value;
 641         count = setp->ls_length;
 642         start = &setp->ls_items[0];
 643         stop = &setp->ls_items[count];
 644         if (startp)
 645                *startp = start;
 646         if (stopp)
 647                *stopp = stop;
 648         if (countp)
 649                *countp = count;
 650         return 0;
 651 }