sys/kern/imgact_elf.c

   1 /*-
   2  * Copyright (c) 1995-1996 Søren Schmidt
   3  * Copyright (c) 1996 Peter Wemm
   4  * All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  * 1. Redistributions of source code must retain the above copyright
  10  *    notice, this list of conditions and the following disclaimer
  11  *    in this position and unchanged.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  * 3. The name of the author may not be used to endorse or promote products
  16  *    derived from this software withough specific prior written permission
  17  *
  18  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  19  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  20  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  21  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  22  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  23  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  24  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  25  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  26  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  27  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  28  *
  29  * $FreeBSD: src/sys/kern/imgact_elf.c,v 1.73.2.13 2002/12/28 19:49:41 dillon Exp $
  30  * $DragonFly: src/sys/kern/imgact_elf.c,v 1.6 2003/08/03 10:07:41 hmp Exp $
  31  */
  32
  33 #include <sys/param.h>
  34 #include <sys/exec.h>
  35 #include <sys/fcntl.h>
  36 #include <sys/imgact.h>
  37 #include <sys/imgact_elf.h>
  38 #include <sys/kernel.h>
  39 #include <sys/malloc.h>
  40 #include <sys/mman.h>
  41 #include <sys/systm.h>
  42 #include <sys/proc.h>
  43 #include <sys/namei.h>
  44 #include <sys/pioctl.h>
  45 #include <sys/procfs.h>
  46 #include <sys/resourcevar.h>
  47 #include <sys/signalvar.h>
  48 #include <sys/stat.h>
  49 #include <sys/syscall.h>
  50 #include <sys/sysctl.h>
  51 #include <sys/sysent.h>
  52 #include <sys/vnode.h>
  53
  54 #include <vm/vm.h>
  55 #include <vm/vm_kern.h>
  56 #include <vm/vm_param.h>
  57 #include <vm/pmap.h>
  58 #include <sys/lock.h>
  59 #include <vm/vm_map.h>
  60 #include <vm/vm_object.h>
  61 #include <vm/vm_extern.h>
  62
  63 #include <machine/elf.h>
  64 #include <machine/md_var.h>
  65
  66 #define OLD_EI_BRAND    8
  67
  68 __ElfType(Brandinfo);
  69 __ElfType(Auxargs);
  70
  71 static int elf_check_header __P((const Elf_Ehdr *hdr));
  72 static int elf_freebsd_fixup __P((register_t **stack_base,
  73     struct image_params *imgp));
  74 static int elf_load_file __P((struct proc *p, const char *file, u_long *addr,
  75     u_long *entry));
  76 static int elf_load_section __P((struct proc *p,
  77     struct vmspace *vmspace, struct vnode *vp,
  78     vm_offset_t offset, caddr_t vmaddr, size_t memsz, size_t filsz,
  79     vm_prot_t prot));
  80 static int exec_elf_imgact __P((struct image_params *imgp));
  81
  82 static int elf_trace = 0;
  83 SYSCTL_INT(_debug, OID_AUTO, elf_trace, CTLFLAG_RW, &elf_trace, 0, "");
  84 static int elf_legacy_coredump = 0;
  85 SYSCTL_INT(_debug, OID_AUTO, elf_legacy_coredump, CTLFLAG_RW,
  86     &elf_legacy_coredump, 0, "");
  87
  88 static struct sysentvec elf_freebsd_sysvec = {
  89         SYS_MAXSYSCALL,
  90         sysent,
  91         0,
  92         0,
  93         0,
  94         0,
  95         0,
  96         0,
  97         elf_freebsd_fixup,
  98         sendsig,
  99         sigcode,
 100         &szsigcode,
 101         0,
 102         "FreeBSD ELF",
 103         elf_coredump,
 104         NULL,
 105         MINSIGSTKSZ
 106 };
 107
 108 static Elf_Brandinfo freebsd_brand_info = {
 109                                                 ELFOSABI_FREEBSD,
 110                                                 "FreeBSD",
 111                                                 "",
 112                                                 "/usr/libexec/ld-elf.so.1",
 113                                                 &elf_freebsd_sysvec
 114                                           };
 115 static Elf_Brandinfo *elf_brand_list[MAX_BRANDS] = {
 116                                                         &freebsd_brand_info,
 117                                                         NULL, NULL, NULL,
 118                                                         NULL, NULL, NULL, NULL
 119                                                     };
 120
 121 int
 122 elf_insert_brand_entry(Elf_Brandinfo *entry)
 123 {
 124         int i;
 125
 126         for (i=1; i<MAX_BRANDS; i++) {
 127                 if (elf_brand_list[i] == NULL) {
 128                         elf_brand_list[i] = entry;
 129                         break;
 130                 }
 131         }
 132         if (i == MAX_BRANDS)
 133                 return -1;
 134         return 0;
 135 }
 136
 137 int
 138 elf_remove_brand_entry(Elf_Brandinfo *entry)
 139 {
 140         int i;
 141
 142         for (i=1; i<MAX_BRANDS; i++) {
 143                 if (elf_brand_list[i] == entry) {
 144                         elf_brand_list[i] = NULL;
 145                         break;
 146                 }
 147         }
 148         if (i == MAX_BRANDS)
 149                 return -1;
 150         return 0;
 151 }
 152
 153 int
 154 elf_brand_inuse(Elf_Brandinfo *entry)
 155 {
 156         struct proc *p;
 157         int rval = FALSE;
 158
 159         FOREACH_PROC_IN_SYSTEM(p) {
 160                 if (p->p_sysent == entry->sysvec) {
 161                         rval = TRUE;
 162                         break;
 163                 }
 164         }
 165
 166         return (rval);
 167 }
 168
 169 static int
 170 elf_check_header(const Elf_Ehdr *hdr)
 171 {
 172         if (!IS_ELF(*hdr) ||
 173             hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS ||
 174             hdr->e_ident[EI_DATA] != ELF_TARG_DATA ||
 175             hdr->e_ident[EI_VERSION] != EV_CURRENT)
 176                 return ENOEXEC;
 177
 178         if (!ELF_MACHINE_OK(hdr->e_machine))
 179                 return ENOEXEC;
 180
 181         if (hdr->e_version != ELF_TARG_VER)
 182                 return ENOEXEC;
 183
 184         return 0;
 185 }
 186
 187 static int
 188 elf_load_section(struct proc *p, struct vmspace *vmspace, struct vnode *vp, vm_offset_t offset, caddr_t vmaddr, size_t memsz, size_t filsz, vm_prot_t prot)
 189 {
 190         size_t map_len;
 191         vm_offset_t map_addr;
 192         int error, rv, cow;
 193         size_t copy_len;
 194         vm_object_t object;
 195         vm_offset_t file_addr;
 196         vm_offset_t data_buf = 0;
 197
 198         VOP_GETVOBJECT(vp, &object);
 199         error = 0;
 200
 201         /*
 202          * It's necessary to fail if the filsz + offset taken from the
 203          * header is greater than the actual file pager object's size.
 204          * If we were to allow this, then the vm_map_find() below would
 205          * walk right off the end of the file object and into the ether.
 206          *
 207          * While I'm here, might as well check for something else that
 208          * is invalid: filsz cannot be greater than memsz.
 209          */
 210         if ((off_t)filsz + offset > object->un_pager.vnp.vnp_size ||
 211             filsz > memsz) {
 212                 uprintf("elf_load_section: truncated ELF file\n");
 213                 return (ENOEXEC);
 214         }
 215
 216         map_addr = trunc_page((vm_offset_t)vmaddr);
 217         file_addr = trunc_page(offset);
 218
 219         /*
 220          * We have two choices.  We can either clear the data in the last page
 221          * of an oversized mapping, or we can start the anon mapping a page
 222          * early and copy the initialized data into that first page.  We
 223          * choose the second..
 224          */
 225         if (memsz > filsz)
 226                 map_len = trunc_page(offset+filsz) - file_addr;
 227         else
 228                 map_len = round_page(offset+filsz) - file_addr;
 229
 230         if (map_len != 0) {
 231                 vm_object_reference(object);
 232
 233                 /* cow flags: don't dump readonly sections in core */
 234                 cow = MAP_COPY_ON_WRITE | MAP_PREFAULT |
 235                     (prot & VM_PROT_WRITE ? 0 : MAP_DISABLE_COREDUMP);
 236
 237                 vm_map_lock(&vmspace->vm_map);
 238                 rv = vm_map_insert(&vmspace->vm_map,
 239                                       object,
 240                                       file_addr,        /* file offset */
 241                                       map_addr,         /* virtual start */
 242                                       map_addr + map_len,/* virtual end */
 243                                       prot,
 244                                       VM_PROT_ALL,
 245                                       cow);
 246                 vm_map_unlock(&vmspace->vm_map);
 247                 if (rv != KERN_SUCCESS) {
 248                         vm_object_deallocate(object);
 249                         return EINVAL;
 250                 }
 251
 252                 /* we can stop now if we've covered it all */
 253                 if (memsz == filsz) {
 254                         return 0;
 255                 }
 256         }
 257
 258
 259         /*
 260          * We have to get the remaining bit of the file into the first part
 261          * of the oversized map segment.  This is normally because the .data
 262          * segment in the file is extended to provide bss.  It's a neat idea
 263          * to try and save a page, but it's a pain in the behind to implement.
 264          */
 265         copy_len = (offset + filsz) - trunc_page(offset + filsz);
 266         map_addr = trunc_page((vm_offset_t)vmaddr + filsz);
 267         map_len = round_page((vm_offset_t)vmaddr + memsz) - map_addr;
 268
 269         /* This had damn well better be true! */
 270         if (map_len != 0) {
 271                 vm_map_lock(&vmspace->vm_map);
 272                 rv = vm_map_insert(&vmspace->vm_map, NULL, 0,
 273                                         map_addr, map_addr + map_len,
 274                                         VM_PROT_ALL, VM_PROT_ALL, 0);
 275                 vm_map_unlock(&vmspace->vm_map);
 276                 if (rv != KERN_SUCCESS) {
 277                         return EINVAL;
 278                 }
 279         }
 280
 281         if (copy_len != 0) {
 282                 vm_object_reference(object);
 283                 rv = vm_map_find(exec_map,
 284                                  object,
 285                                  trunc_page(offset + filsz),
 286                                  &data_buf,
 287                                  PAGE_SIZE,
 288                                  TRUE,
 289                                  VM_PROT_READ,
 290                                  VM_PROT_ALL,
 291                                  MAP_COPY_ON_WRITE | MAP_PREFAULT_PARTIAL);
 292                 if (rv != KERN_SUCCESS) {
 293                         vm_object_deallocate(object);
 294                         return EINVAL;
 295                 }
 296
 297                 /* send the page fragment to user space */
 298                 error = copyout((caddr_t)data_buf, (caddr_t)map_addr, copy_len);
 299                 vm_map_remove(exec_map, data_buf, data_buf + PAGE_SIZE);
 300                 if (error) {
 301                         return (error);
 302                 }
 303         }
 304
 305         /*
 306          * set it to the specified protection
 307          */
 308         vm_map_protect(&vmspace->vm_map, map_addr, map_addr + map_len,  prot,
 309                        FALSE);
 310
 311         return error;
 312 }
 313
 314 /*
 315  * Load the file "file" into memory.  It may be either a shared object
 316  * or an executable.
 317  *
 318  * The "addr" reference parameter is in/out.  On entry, it specifies
 319  * the address where a shared object should be loaded.  If the file is
 320  * an executable, this value is ignored.  On exit, "addr" specifies
 321  * where the file was actually loaded.
 322  *
 323  * The "entry" reference parameter is out only.  On exit, it specifies
 324  * the entry point for the loaded file.
 325  */
 326 static int
 327 elf_load_file(struct proc *p, const char *file, u_long *addr, u_long *entry)
 328 {
 329         struct {
 330                 struct nameidata nd;
 331                 struct vattr attr;
 332                 struct image_params image_params;
 333         } *tempdata;
 334         const Elf_Ehdr *hdr = NULL;
 335         const Elf_Phdr *phdr = NULL;
 336         struct nameidata *nd;
 337         struct vmspace *vmspace = p->p_vmspace;
 338         struct vattr *attr;
 339         struct image_params *imgp;
 340         vm_prot_t prot;
 341         u_long rbase;
 342         u_long base_addr = 0;
 343         int error, i, numsegs;
 344         struct thread *td = p->p_thread;
 345
 346         tempdata = malloc(sizeof(*tempdata), M_TEMP, M_WAITOK);
 347         nd = &tempdata->nd;
 348         attr = &tempdata->attr;
 349         imgp = &tempdata->image_params;
 350
 351         /*
 352          * Initialize part of the common data
 353          */
 354         imgp->proc = p;
 355         imgp->uap = NULL;
 356         imgp->attr = attr;
 357         imgp->firstpage = NULL;
 358         imgp->image_header = (char *)kmem_alloc_wait(exec_map, PAGE_SIZE);
 359
 360         if (imgp->image_header == NULL) {
 361                 nd->ni_vp = NULL;
 362                 error = ENOMEM;
 363                 goto fail;
 364         }
 365
 366         NDINIT(nd, LOOKUP, LOCKLEAF|FOLLOW, UIO_SYSSPACE, file, td);
 367
 368         if ((error = namei(nd)) != 0) {
 369                 nd->ni_vp = NULL;
 370                 goto fail;
 371         }
 372         NDFREE(nd, NDF_ONLY_PNBUF);
 373         imgp->vp = nd->ni_vp;
 374
 375         /*
 376          * Check permissions, modes, uid, etc on the file, and "open" it.
 377          */
 378         error = exec_check_permissions(imgp);
 379         if (error) {
 380                 VOP_UNLOCK(nd->ni_vp, 0, td);
 381                 goto fail;
 382         }
 383
 384         error = exec_map_first_page(imgp);
 385         /*
 386          * Also make certain that the interpreter stays the same, so set
 387          * its VTEXT flag, too.
 388          */
 389         if (error == 0)
 390                 nd->ni_vp->v_flag |= VTEXT;
 391         VOP_UNLOCK(nd->ni_vp, 0, td);
 392         if (error)
 393                 goto fail;
 394
 395         hdr = (const Elf_Ehdr *)imgp->image_header;
 396         if ((error = elf_check_header(hdr)) != 0)
 397                 goto fail;
 398         if (hdr->e_type == ET_DYN)
 399                 rbase = *addr;
 400         else if (hdr->e_type == ET_EXEC)
 401                 rbase = 0;
 402         else {
 403                 error = ENOEXEC;
 404                 goto fail;
 405         }
 406
 407         /* Only support headers that fit within first page for now */
 408         if ((hdr->e_phoff > PAGE_SIZE) ||
 409             (hdr->e_phoff + hdr->e_phentsize * hdr->e_phnum) > PAGE_SIZE) {
 410                 error = ENOEXEC;
 411                 goto fail;
 412         }
 413
 414         phdr = (const Elf_Phdr *)(imgp->image_header + hdr->e_phoff);
 415
 416         for (i = 0, numsegs = 0; i < hdr->e_phnum; i++) {
 417                 if (phdr[i].p_type == PT_LOAD) {        /* Loadable segment */
 418                         prot = 0;
 419                         if (phdr[i].p_flags & PF_X)
 420                                 prot |= VM_PROT_EXECUTE;
 421                         if (phdr[i].p_flags & PF_W)
 422                                 prot |= VM_PROT_WRITE;
 423                         if (phdr[i].p_flags & PF_R)
 424                                 prot |= VM_PROT_READ;
 425
 426                         error = elf_load_section(
 427                                     p, vmspace, nd->ni_vp,
 428                                     phdr[i].p_offset,
 429                                     (caddr_t)phdr[i].p_vaddr +
 430                                     rbase,
 431                                     phdr[i].p_memsz,
 432                                     phdr[i].p_filesz, prot);
 433                         if (error != 0)
 434                                 goto fail;
 435                         /*
 436                          * Establish the base address if this is the
 437                          * first segment.
 438                          */
 439                         if (numsegs == 0)
 440                                 base_addr = trunc_page(phdr[i].p_vaddr + rbase);
 441                         numsegs++;
 442                 }
 443         }
 444         *addr = base_addr;
 445         *entry=(unsigned long)hdr->e_entry + rbase;
 446
 447 fail:
 448         if (imgp->firstpage)
 449                 exec_unmap_first_page(imgp);
 450         if (imgp->image_header)
 451                 kmem_free_wakeup(exec_map, (vm_offset_t)imgp->image_header,
 452                         PAGE_SIZE);
 453         if (nd->ni_vp)
 454                 vrele(nd->ni_vp);
 455
 456         free(tempdata, M_TEMP);
 457
 458         return error;
 459 }
 460
 461 /*
 462  * non static, as it can be overridden by start_init()
 463  */
 464 int fallback_elf_brand = -1;
 465 SYSCTL_INT(_kern, OID_AUTO, fallback_elf_brand, CTLFLAG_RW,
 466                 &fallback_elf_brand, -1,
 467                 "ELF brand of last resort");
 468
 469 static int
 470 exec_elf_imgact(struct image_params *imgp)
 471 {
 472         const Elf_Ehdr *hdr = (const Elf_Ehdr *) imgp->image_header;
 473         const Elf_Phdr *phdr;
 474         Elf_Auxargs *elf_auxargs = NULL;
 475         struct vmspace *vmspace;
 476         vm_prot_t prot;
 477         u_long text_size = 0, data_size = 0, total_size = 0;
 478         u_long text_addr = 0, data_addr = 0;
 479         u_long seg_size, seg_addr;
 480         u_long addr, entry = 0, proghdr = 0;
 481         int error, i;
 482         const char *interp = NULL;
 483         Elf_Brandinfo *brand_info;
 484         char *path;
 485
 486         /*
 487          * Do we have a valid ELF header ?
 488          */
 489         if (elf_check_header(hdr) != 0 || hdr->e_type != ET_EXEC)
 490                 return -1;
 491
 492         /*
 493          * From here on down, we return an errno, not -1, as we've
 494          * detected an ELF file.
 495          */
 496
 497         if ((hdr->e_phoff > PAGE_SIZE) ||
 498             (hdr->e_phoff + hdr->e_phentsize * hdr->e_phnum) > PAGE_SIZE) {
 499                 /* Only support headers in first page for now */
 500                 return ENOEXEC;
 501         }
 502         phdr = (const Elf_Phdr*)(imgp->image_header + hdr->e_phoff);
 503
 504         /*
 505          * From this point on, we may have resources that need to be freed.
 506          */
 507
 508         if ((error = exec_extract_strings(imgp)) != 0)
 509                 goto fail;
 510
 511         exec_new_vmspace(imgp);
 512
 513         /*
 514          * Yeah, I'm paranoid.  There is every reason in the world to get
 515          * VTEXT now since from here on out, there are places we can have
 516          * a context switch.  Better safe than sorry; I really don't want
 517          * the file to change while it's being loaded.
 518          */
 519         lwkt_gettoken(&imgp->vp->v_interlock);
 520         imgp->vp->v_flag |= VTEXT;
 521         lwkt_reltoken(&imgp->vp->v_interlock);
 522
 523         vmspace = imgp->proc->p_vmspace;
 524
 525         for (i = 0; i < hdr->e_phnum; i++) {
 526                 switch(phdr[i].p_type) {
 527
 528                 case PT_LOAD:   /* Loadable segment */
 529                         prot = 0;
 530                         if (phdr[i].p_flags & PF_X)
 531                                 prot |= VM_PROT_EXECUTE;
 532                         if (phdr[i].p_flags & PF_W)
 533                                 prot |= VM_PROT_WRITE;
 534                         if (phdr[i].p_flags & PF_R)
 535                                 prot |= VM_PROT_READ;
 536
 537                         if ((error = elf_load_section(imgp->proc,
 538                                                      vmspace, imgp->vp,
 539                                                      phdr[i].p_offset,
 540                                                      (caddr_t)phdr[i].p_vaddr,
 541                                                      phdr[i].p_memsz,
 542                                                      phdr[i].p_filesz, prot)) != 0)
 543                                 goto fail;
 544
 545                         seg_addr = trunc_page(phdr[i].p_vaddr);
 546                         seg_size = round_page(phdr[i].p_memsz +
 547                                 phdr[i].p_vaddr - seg_addr);
 548
 549                         /*
 550                          * Is this .text or .data?  We can't use
 551                          * VM_PROT_WRITE or VM_PROT_EXEC, it breaks the
 552                          * alpha terribly and possibly does other bad
 553                          * things so we stick to the old way of figuring
 554                          * it out:  If the segment contains the program
 555                          * entry point, it's a text segment, otherwise it
 556                          * is a data segment.
 557                          *
 558                          * Note that obreak() assumes that data_addr +
 559                          * data_size == end of data load area, and the ELF
 560                          * file format expects segments to be sorted by
 561                          * address.  If multiple data segments exist, the
 562                          * last one will be used.
 563                          */
 564                         if (hdr->e_entry >= phdr[i].p_vaddr &&
 565                             hdr->e_entry < (phdr[i].p_vaddr +
 566                             phdr[i].p_memsz)) {
 567                                 text_size = seg_size;
 568                                 text_addr = seg_addr;
 569                                 entry = (u_long)hdr->e_entry;
 570                         } else {
 571                                 data_size = seg_size;
 572                                 data_addr = seg_addr;
 573                         }
 574                         total_size += seg_size;
 575
 576                         /*
 577                          * Check limits.  It should be safe to check the
 578                          * limits after loading the segment since we do
 579                          * not actually fault in all the segment's pages.
 580                          */
 581                         if (data_size >
 582                             imgp->proc->p_rlimit[RLIMIT_DATA].rlim_cur ||
 583                             text_size > maxtsiz ||
 584                             total_size >
 585                             imgp->proc->p_rlimit[RLIMIT_VMEM].rlim_cur) {
 586                                 error = ENOMEM;
 587                                 goto fail;
 588                         }
 589                         break;
 590                 case PT_INTERP: /* Path to interpreter */
 591                         if (phdr[i].p_filesz > MAXPATHLEN ||
 592                             phdr[i].p_offset + phdr[i].p_filesz > PAGE_SIZE) {
 593                                 error = ENOEXEC;
 594                                 goto fail;
 595                         }
 596                         interp = imgp->image_header + phdr[i].p_offset;
 597                         break;
 598                 case PT_PHDR:   /* Program header table info */
 599                         proghdr = phdr[i].p_vaddr;
 600                         break;
 601                 default:
 602                         break;
 603                 }
 604         }
 605
 606         vmspace->vm_tsize = text_size >> PAGE_SHIFT;
 607         vmspace->vm_taddr = (caddr_t)(uintptr_t)text_addr;
 608         vmspace->vm_dsize = data_size >> PAGE_SHIFT;
 609         vmspace->vm_daddr = (caddr_t)(uintptr_t)data_addr;
 610
 611         addr = ELF_RTLD_ADDR(vmspace);
 612
 613         imgp->entry_addr = entry;
 614
 615         brand_info = NULL;
 616
 617         /* We support three types of branding -- (1) the ELF EI_OSABI field
 618          * that SCO added to the ELF spec, (2) FreeBSD 3.x's traditional string
 619          * branding w/in the ELF header, and (3) path of the `interp_path'
 620          * field.  We should also look for an ".note.ABI-tag" ELF section now
 621          * in all Linux ELF binaries, FreeBSD 4.1+, and some NetBSD ones.
 622          */
 623
 624         /* If the executable has a brand, search for it in the brand list. */
 625         if (brand_info == NULL) {
 626                 for (i = 0;  i < MAX_BRANDS;  i++) {
 627                         Elf_Brandinfo *bi = elf_brand_list[i];
 628
 629                         if (bi != NULL &&
 630                             (hdr->e_ident[EI_OSABI] == bi->brand
 631                             || 0 ==
 632                             strncmp((const char *)&hdr->e_ident[OLD_EI_BRAND],
 633                             bi->compat_3_brand, strlen(bi->compat_3_brand)))) {
 634                                 brand_info = bi;
 635                                 break;
 636                         }
 637                 }
 638         }
 639
 640         /* Lacking a known brand, search for a recognized interpreter. */
 641         if (brand_info == NULL && interp != NULL) {
 642                 for (i = 0;  i < MAX_BRANDS;  i++) {
 643                         Elf_Brandinfo *bi = elf_brand_list[i];
 644
 645                         if (bi != NULL &&
 646                             strcmp(interp, bi->interp_path) == 0) {
 647                                 brand_info = bi;
 648                                 break;
 649                         }
 650                 }
 651         }
 652
 653         /* Lacking a recognized interpreter, try the default brand */
 654         if (brand_info == NULL) {
 655                 for (i = 0; i < MAX_BRANDS; i++) {
 656                         Elf_Brandinfo *bi = elf_brand_list[i];
 657
 658                         if (bi != NULL && fallback_elf_brand == bi->brand) {
 659                                 brand_info = bi;
 660                                 break;
 661                         }
 662                 }
 663         }
 664
 665         if (brand_info == NULL) {
 666                 uprintf("ELF binary type \"%u\" not known.\n",
 667                     hdr->e_ident[EI_OSABI]);
 668                 error = ENOEXEC;
 669                 goto fail;
 670         }
 671
 672         imgp->proc->p_sysent = brand_info->sysvec;
 673         if (interp != NULL) {
 674                 path = malloc(MAXPATHLEN, M_TEMP, M_WAITOK);
 675                 snprintf(path, MAXPATHLEN, "%s%s",
 676                          brand_info->emul_path, interp);
 677                 if ((error = elf_load_file(imgp->proc, path, &addr,
 678                                            &imgp->entry_addr)) != 0) {
 679                         if ((error = elf_load_file(imgp->proc, interp, &addr,
 680                                                    &imgp->entry_addr)) != 0) {
 681                                 uprintf("ELF interpreter %s not found\n", path);
 682                                 free(path, M_TEMP);
 683                                 goto fail;
 684                         }
 685                 }
 686                 free(path, M_TEMP);
 687         }
 688
 689         /*
 690          * Construct auxargs table (used by the fixup routine)
 691          */
 692         elf_auxargs = malloc(sizeof(Elf_Auxargs), M_TEMP, M_WAITOK);
 693         elf_auxargs->execfd = -1;
 694         elf_auxargs->phdr = proghdr;
 695         elf_auxargs->phent = hdr->e_phentsize;
 696         elf_auxargs->phnum = hdr->e_phnum;
 697         elf_auxargs->pagesz = PAGE_SIZE;
 698         elf_auxargs->base = addr;
 699         elf_auxargs->flags = 0;
 700         elf_auxargs->entry = entry;
 701         elf_auxargs->trace = elf_trace;
 702
 703         imgp->auxargs = elf_auxargs;
 704         imgp->interpreted = 0;
 705
 706 fail:
 707         return error;
 708 }
 709
 710 static int
 711 elf_freebsd_fixup(register_t **stack_base, struct image_params *imgp)
 712 {
 713         Elf_Auxargs *args = (Elf_Auxargs *)imgp->auxargs;
 714         register_t *pos;
 715
 716         pos = *stack_base + (imgp->argc + imgp->envc + 2);
 717
 718         if (args->trace) {
 719                 AUXARGS_ENTRY(pos, AT_DEBUG, 1);
 720         }
 721         if (args->execfd != -1) {
 722                 AUXARGS_ENTRY(pos, AT_EXECFD, args->execfd);
 723         }
 724         AUXARGS_ENTRY(pos, AT_PHDR, args->phdr);
 725         AUXARGS_ENTRY(pos, AT_PHENT, args->phent);
 726         AUXARGS_ENTRY(pos, AT_PHNUM, args->phnum);
 727         AUXARGS_ENTRY(pos, AT_PAGESZ, args->pagesz);
 728         AUXARGS_ENTRY(pos, AT_FLAGS, args->flags);
 729         AUXARGS_ENTRY(pos, AT_ENTRY, args->entry);
 730         AUXARGS_ENTRY(pos, AT_BASE, args->base);
 731         AUXARGS_ENTRY(pos, AT_NULL, 0);
 732
 733         free(imgp->auxargs, M_TEMP);
 734         imgp->auxargs = NULL;
 735
 736         (*stack_base)--;
 737         suword(*stack_base, (long) imgp->argc);
 738         return 0;
 739 }
 740
 741 /*
 742  * Code for generating ELF core dumps.
 743  */
 744
 745 typedef void (*segment_callback) __P((vm_map_entry_t, void *));
 746
 747 /* Closure for cb_put_phdr(). */
 748 struct phdr_closure {
 749         Elf_Phdr *phdr;         /* Program header to fill in */
 750         Elf_Off offset;         /* Offset of segment in core file */
 751 };
 752
 753 /* Closure for cb_size_segment(). */
 754 struct sseg_closure {
 755         int count;              /* Count of writable segments. */
 756         size_t size;            /* Total size of all writable segments. */
 757 };
 758
 759 static void cb_put_phdr __P((vm_map_entry_t, void *));
 760 static void cb_size_segment __P((vm_map_entry_t, void *));
 761 static void each_writable_segment __P((struct proc *, segment_callback,
 762     void *));
 763 static int elf_corehdr __P((struct proc *, struct vnode *, struct ucred *,
 764     int, void *, size_t));
 765 static void elf_puthdr __P((struct proc *, void *, size_t *,
 766     const prstatus_t *, const prfpregset_t *, const prpsinfo_t *, int));
 767 static void elf_putnote __P((void *, size_t *, const char *, int,
 768     const void *, size_t));
 769
 770 extern int osreldate;
 771
 772 int
 773 elf_coredump(p, vp, limit)
 774         struct proc *p;
 775         struct vnode *vp;
 776         off_t limit;
 777 {
 778         struct ucred *cred = p->p_ucred;
 779         struct thread *td = p->p_thread;
 780         int error = 0;
 781         struct sseg_closure seginfo;
 782         void *hdr;
 783         size_t hdrsize;
 784
 785         /* Size the program segments. */
 786         seginfo.count = 0;
 787         seginfo.size = 0;
 788         each_writable_segment(p, cb_size_segment, &seginfo);
 789
 790         /*
 791          * Calculate the size of the core file header area by making
 792          * a dry run of generating it.  Nothing is written, but the
 793          * size is calculated.
 794          */
 795         hdrsize = 0;
 796         elf_puthdr((struct proc *)NULL, (void *)NULL, &hdrsize,
 797             (const prstatus_t *)NULL, (const prfpregset_t *)NULL,
 798             (const prpsinfo_t *)NULL, seginfo.count);
 799
 800         if (hdrsize + seginfo.size >= limit)
 801                 return (EFAULT);
 802
 803         /*
 804          * Allocate memory for building the header, fill it up,
 805          * and write it out.
 806          */
 807         hdr = malloc(hdrsize, M_TEMP, M_WAITOK);
 808         if (hdr == NULL) {
 809                 return EINVAL;
 810         }
 811         error = elf_corehdr(p, vp, cred, seginfo.count, hdr, hdrsize);
 812
 813         /* Write the contents of all of the writable segments. */
 814         if (error == 0) {
 815                 Elf_Phdr *php;
 816                 off_t offset;
 817                 int i;
 818
 819                 php = (Elf_Phdr *)((char *)hdr + sizeof(Elf_Ehdr)) + 1;
 820                 offset = hdrsize;
 821                 for (i = 0;  i < seginfo.count;  i++) {
 822                         error = vn_rdwr_inchunks(UIO_WRITE, vp,
 823                             (caddr_t)php->p_vaddr,
 824                             php->p_filesz, offset, UIO_USERSPACE,
 825                             IO_UNIT | IO_DIRECT | IO_CORE, cred,
 826                             (int *)NULL, td);
 827                         if (error != 0)
 828                                 break;
 829                         offset += php->p_filesz;
 830                         php++;
 831                 }
 832         }
 833         free(hdr, M_TEMP);
 834
 835         return error;
 836 }
 837
 838 /*
 839  * A callback for each_writable_segment() to write out the segment's
 840  * program header entry.
 841  */
 842 static void
 843 cb_put_phdr(entry, closure)
 844         vm_map_entry_t entry;
 845         void *closure;
 846 {
 847         struct phdr_closure *phc = (struct phdr_closure *)closure;
 848         Elf_Phdr *phdr = phc->phdr;
 849
 850         phc->offset = round_page(phc->offset);
 851
 852         phdr->p_type = PT_LOAD;
 853         phdr->p_offset = phc->offset;
 854         phdr->p_vaddr = entry->start;
 855         phdr->p_paddr = 0;
 856         phdr->p_filesz = phdr->p_memsz = entry->end - entry->start;
 857         phdr->p_align = PAGE_SIZE;
 858         phdr->p_flags = 0;
 859         if (entry->protection & VM_PROT_READ)
 860                 phdr->p_flags |= PF_R;
 861         if (entry->protection & VM_PROT_WRITE)
 862                 phdr->p_flags |= PF_W;
 863         if (entry->protection & VM_PROT_EXECUTE)
 864                 phdr->p_flags |= PF_X;
 865
 866         phc->offset += phdr->p_filesz;
 867         phc->phdr++;
 868 }
 869
 870 /*
 871  * A callback for each_writable_segment() to gather information about
 872  * the number of segments and their total size.
 873  */
 874 static void
 875 cb_size_segment(entry, closure)
 876         vm_map_entry_t entry;
 877         void *closure;
 878 {
 879         struct sseg_closure *ssc = (struct sseg_closure *)closure;
 880
 881         ssc->count++;
 882         ssc->size += entry->end - entry->start;
 883 }
 884
 885 /*
 886  * For each writable segment in the process's memory map, call the given
 887  * function with a pointer to the map entry and some arbitrary
 888  * caller-supplied data.
 889  */
 890 static void
 891 each_writable_segment(p, func, closure)
 892         struct proc *p;
 893         segment_callback func;
 894         void *closure;
 895 {
 896         vm_map_t map = &p->p_vmspace->vm_map;
 897         vm_map_entry_t entry;
 898
 899         for (entry = map->header.next;  entry != &map->header;
 900             entry = entry->next) {
 901                 vm_object_t obj;
 902
 903                 /*
 904                  * Don't dump inaccessible mappings, deal with legacy
 905                  * coredump mode.
 906                  *
 907                  * Note that read-only segments related to the elf binary
 908                  * are marked MAP_ENTRY_NOCOREDUMP now so we no longer
 909                  * need to arbitrarily ignore such segments.
 910                  */
 911                 if (elf_legacy_coredump) {
 912                         if ((entry->protection & VM_PROT_RW) != VM_PROT_RW)
 913                                 continue;
 914                 } else {
 915                         if ((entry->protection & VM_PROT_ALL) == 0)
 916                                 continue;
 917                 }
 918
 919                 /*
 920                  * Dont include memory segment in the coredump if
 921                  * MAP_NOCORE is set in mmap(2) or MADV_NOCORE in
 922                  * madvise(2).  Do not dump submaps (i.e. parts of the
 923                  * kernel map).
 924                  */
 925                 if (entry->eflags & (MAP_ENTRY_NOCOREDUMP|MAP_ENTRY_IS_SUB_MAP))
 926                         continue;
 927
 928                 if ((obj = entry->object.vm_object) == NULL)
 929                         continue;
 930
 931                 /* Find the deepest backing object. */
 932                 while (obj->backing_object != NULL)
 933                         obj = obj->backing_object;
 934
 935                 /* Ignore memory-mapped devices and such things. */
 936                 if (obj->type != OBJT_DEFAULT &&
 937                     obj->type != OBJT_SWAP &&
 938                     obj->type != OBJT_VNODE)
 939                         continue;
 940
 941                 (*func)(entry, closure);
 942         }
 943 }
 944
 945 /*
 946  * Write the core file header to the file, including padding up to
 947  * the page boundary.
 948  */
 949 static int
 950 elf_corehdr(p, vp, cred, numsegs, hdr, hdrsize)
 951         struct proc *p;
 952         struct vnode *vp;
 953         struct ucred *cred;
 954         int numsegs;
 955         size_t hdrsize;
 956         void *hdr;
 957 {
 958         struct {
 959                 prstatus_t status;
 960                 prfpregset_t fpregset;
 961                 prpsinfo_t psinfo;
 962         } *tempdata;
 963         size_t off;
 964         prstatus_t *status;
 965         prfpregset_t *fpregset;
 966         prpsinfo_t *psinfo;
 967         struct thread *td = p->p_thread;
 968
 969         tempdata = malloc(sizeof(*tempdata), M_TEMP, M_ZERO | M_WAITOK);
 970         status = &tempdata->status;
 971         fpregset = &tempdata->fpregset;
 972         psinfo = &tempdata->psinfo;
 973
 974         /* Gather the information for the header. */
 975         status->pr_version = PRSTATUS_VERSION;
 976         status->pr_statussz = sizeof(prstatus_t);
 977         status->pr_gregsetsz = sizeof(gregset_t);
 978         status->pr_fpregsetsz = sizeof(fpregset_t);
 979         status->pr_osreldate = osreldate;
 980         status->pr_cursig = p->p_sig;
 981         status->pr_pid = p->p_pid;
 982         fill_regs(p, &status->pr_reg);
 983
 984         fill_fpregs(p, fpregset);
 985
 986         psinfo->pr_version = PRPSINFO_VERSION;
 987         psinfo->pr_psinfosz = sizeof(prpsinfo_t);
 988         strncpy(psinfo->pr_fname, p->p_comm, sizeof(psinfo->pr_fname) - 1);
 989
 990         /* XXX - We don't fill in the command line arguments properly yet. */
 991         strncpy(psinfo->pr_psargs, p->p_comm, PRARGSZ);
 992
 993         /* Fill in the header. */
 994         bzero(hdr, hdrsize);
 995         off = 0;
 996         elf_puthdr(p, hdr, &off, status, fpregset, psinfo, numsegs);
 997
 998         free(tempdata, M_TEMP);
 999
1000         /* Write it to the core file. */
1001         return vn_rdwr_inchunks(UIO_WRITE, vp, hdr, hdrsize, (off_t)0,
1002             UIO_SYSSPACE, IO_UNIT | IO_DIRECT | IO_CORE, cred, NULL, td);
1003 }
1004
1005 static void
1006 elf_puthdr(struct proc *p, void *dst, size_t *off, const prstatus_t *status,
1007     const prfpregset_t *fpregset, const prpsinfo_t *psinfo, int numsegs)
1008 {
1009         size_t ehoff;
1010         size_t phoff;
1011         size_t noteoff;
1012         size_t notesz;
1013
1014         ehoff = *off;
1015         *off += sizeof(Elf_Ehdr);
1016
1017         phoff = *off;
1018         *off += (numsegs + 1) * sizeof(Elf_Phdr);
1019
1020         noteoff = *off;
1021         elf_putnote(dst, off, "FreeBSD", NT_PRSTATUS, status,
1022             sizeof *status);
1023         elf_putnote(dst, off, "FreeBSD", NT_FPREGSET, fpregset,
1024             sizeof *fpregset);
1025         elf_putnote(dst, off, "FreeBSD", NT_PRPSINFO, psinfo,
1026             sizeof *psinfo);
1027         notesz = *off - noteoff;
1028
1029         /* Align up to a page boundary for the program segments. */
1030         *off = round_page(*off);
1031
1032         if (dst != NULL) {
1033                 Elf_Ehdr *ehdr;
1034                 Elf_Phdr *phdr;
1035                 struct phdr_closure phc;
1036
1037                 /*
1038                  * Fill in the ELF header.
1039                  */
1040                 ehdr = (Elf_Ehdr *)((char *)dst + ehoff);
1041                 ehdr->e_ident[EI_MAG0] = ELFMAG0;
1042                 ehdr->e_ident[EI_MAG1] = ELFMAG1;
1043                 ehdr->e_ident[EI_MAG2] = ELFMAG2;
1044                 ehdr->e_ident[EI_MAG3] = ELFMAG3;
1045                 ehdr->e_ident[EI_CLASS] = ELF_CLASS;
1046                 ehdr->e_ident[EI_DATA] = ELF_DATA;
1047                 ehdr->e_ident[EI_VERSION] = EV_CURRENT;
1048                 ehdr->e_ident[EI_OSABI] = ELFOSABI_FREEBSD;
1049                 ehdr->e_ident[EI_ABIVERSION] = 0;
1050                 ehdr->e_ident[EI_PAD] = 0;
1051                 ehdr->e_type = ET_CORE;
1052                 ehdr->e_machine = ELF_ARCH;
1053                 ehdr->e_version = EV_CURRENT;
1054                 ehdr->e_entry = 0;
1055                 ehdr->e_phoff = phoff;
1056                 ehdr->e_flags = 0;
1057                 ehdr->e_ehsize = sizeof(Elf_Ehdr);
1058                 ehdr->e_phentsize = sizeof(Elf_Phdr);
1059                 ehdr->e_phnum = numsegs + 1;
1060                 ehdr->e_shentsize = sizeof(Elf_Shdr);
1061                 ehdr->e_shnum = 0;
1062                 ehdr->e_shstrndx = SHN_UNDEF;
1063
1064                 /*
1065                  * Fill in the program header entries.
1066                  */
1067                 phdr = (Elf_Phdr *)((char *)dst + phoff);
1068
1069                 /* The note segement. */
1070                 phdr->p_type = PT_NOTE;
1071                 phdr->p_offset = noteoff;
1072                 phdr->p_vaddr = 0;
1073                 phdr->p_paddr = 0;
1074                 phdr->p_filesz = notesz;
1075                 phdr->p_memsz = 0;
1076                 phdr->p_flags = 0;
1077                 phdr->p_align = 0;
1078                 phdr++;
1079
1080                 /* All the writable segments from the program. */
1081                 phc.phdr = phdr;
1082                 phc.offset = *off;
1083                 each_writable_segment(p, cb_put_phdr, &phc);
1084         }
1085 }
1086
1087 static void
1088 elf_putnote(void *dst, size_t *off, const char *name, int type,
1089     const void *desc, size_t descsz)
1090 {
1091         Elf_Note note;
1092
1093         note.n_namesz = strlen(name) + 1;
1094         note.n_descsz = descsz;
1095         note.n_type = type;
1096         if (dst != NULL)
1097                 bcopy(&note, (char *)dst + *off, sizeof note);
1098         *off += sizeof note;
1099         if (dst != NULL)
1100                 bcopy(name, (char *)dst + *off, note.n_namesz);
1101         *off += roundup2(note.n_namesz, sizeof(Elf_Size));
1102         if (dst != NULL)
1103                 bcopy(desc, (char *)dst + *off, note.n_descsz);
1104         *off += roundup2(note.n_descsz, sizeof(Elf_Size));
1105 }
1106
1107 /*
1108  * Tell kern_execve.c about it, with a little help from the linker.
1109  */
1110 static struct execsw elf_execsw = {exec_elf_imgact, "ELF"};
1111 EXEC_SET(elf, elf_execsw);