sys/kern/imgact_elf.c

   1 /*-
   2  * Copyright (c) 2000 David O'Brien
   3  * Copyright (c) 1995-1996 Søren Schmidt
   4  * Copyright (c) 1996 Peter Wemm
   5  * All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer
  12  *    in this position and unchanged.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  * 3. The name of the author may not be used to endorse or promote products
  17  *    derived from this software withough specific prior written permission
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  20  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  21  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  22  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  23  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  24  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  25  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  26  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  27  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  28  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  29  *
  30  * $FreeBSD$
  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/lock.h>
  40 #include <sys/malloc.h>
  41 #include <sys/mutex.h>
  42 #include <sys/mman.h>
  43 #include <sys/namei.h>
  44 #include <sys/pioctl.h>
  45 #include <sys/proc.h>
  46 #include <sys/procfs.h>
  47 #include <sys/resourcevar.h>
  48 #include <sys/systm.h>
  49 #include <sys/signalvar.h>
  50 #include <sys/stat.h>
  51 #include <sys/sx.h>
  52 #include <sys/syscall.h>
  53 #include <sys/sysctl.h>
  54 #include <sys/sysent.h>
  55 #include <sys/vnode.h>
  56
  57 #include <vm/vm.h>
  58 #include <vm/vm_kern.h>
  59 #include <vm/vm_param.h>
  60 #include <vm/pmap.h>
  61 #include <vm/vm_map.h>
  62 #include <vm/vm_object.h>
  63 #include <vm/vm_extern.h>
  64
  65 #include <machine/elf.h>
  66 #include <machine/md_var.h>
  67
  68 #define OLD_EI_BRAND    8
  69
  70 __ElfType(Brandinfo);
  71 __ElfType(Auxargs);
  72
  73 static int elf_check_header __P((const Elf_Ehdr *hdr));
  74 static int elf_freebsd_fixup __P((register_t **stack_base,
  75     struct image_params *imgp));
  76 static int elf_load_file __P((struct proc *p, const char *file, u_long *addr,
  77     u_long *entry));
  78 static int elf_load_section __P((struct proc *p,
  79     struct vmspace *vmspace, struct vnode *vp,
  80     vm_offset_t offset, caddr_t vmaddr, size_t memsz, size_t filsz,
  81     vm_prot_t prot));
  82 static int exec_elf_imgact __P((struct image_params *imgp));
  83
  84 static int elf_trace = 0;
  85 SYSCTL_INT(_debug, OID_AUTO, elf_trace, CTLFLAG_RW, &elf_trace, 0, "");
  86
  87 struct sysentvec elf_freebsd_sysvec = {
  88         SYS_MAXSYSCALL,
  89         sysent,
  90         0,
  91         0,
  92         0,
  93         0,
  94         0,
  95         0,
  96         elf_freebsd_fixup,
  97         sendsig,
  98         sigcode,
  99         &szsigcode,
 100         0,
 101         "FreeBSD ELF",
 102         elf_coredump,
 103         NULL,
 104         MINSIGSTKSZ
 105 };
 106
 107 static Elf_Brandinfo freebsd_brand_info = {
 108                                                 ELFOSABI_FREEBSD,
 109                                                 "FreeBSD",
 110                                                 "",
 111                                                 "/usr/libexec/ld-elf.so.1",
 112                                                 &elf_freebsd_sysvec
 113                                           };
 114 static Elf_Brandinfo *elf_brand_list[MAX_BRANDS] = {
 115                                                         &freebsd_brand_info,
 116                                                         NULL, NULL, NULL,
 117                                                         NULL, NULL, NULL, NULL
 118                                                     };
 119
 120 int
 121 elf_insert_brand_entry(Elf_Brandinfo *entry)
 122 {
 123         int i;
 124
 125         for (i=1; i<MAX_BRANDS; i++) {
 126                 if (elf_brand_list[i] == NULL) {
 127                         elf_brand_list[i] = entry;
 128                         break;
 129                 }
 130         }
 131         if (i == MAX_BRANDS)
 132                 return -1;
 133         return 0;
 134 }
 135
 136 int
 137 elf_remove_brand_entry(Elf_Brandinfo *entry)
 138 {
 139         int i;
 140
 141         for (i=1; i<MAX_BRANDS; i++) {
 142                 if (elf_brand_list[i] == entry) {
 143                         elf_brand_list[i] = NULL;
 144                         break;
 145                 }
 146         }
 147         if (i == MAX_BRANDS)
 148                 return -1;
 149         return 0;
 150 }
 151
 152 int
 153 elf_brand_inuse(Elf_Brandinfo *entry)
 154 {
 155         struct proc *p;
 156         int rval = FALSE;
 157
 158         sx_slock(&allproc_lock);
 159         LIST_FOREACH(p, &allproc, p_list) {
 160                 if (p->p_sysent == entry->sysvec) {
 161                         rval = TRUE;
 162                         break;
 163                 }
 164         }
 165         sx_sunlock(&allproc_lock);
 166
 167         return (rval);
 168 }
 169
 170 static int
 171 elf_check_header(const Elf_Ehdr *hdr)
 172 {
 173         if (!IS_ELF(*hdr) ||
 174             hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS ||
 175             hdr->e_ident[EI_DATA] != ELF_TARG_DATA ||
 176             hdr->e_ident[EI_VERSION] != EV_CURRENT)
 177                 return ENOEXEC;
 178
 179         if (!ELF_MACHINE_OK(hdr->e_machine))
 180                 return ENOEXEC;
 181
 182         if (hdr->e_version != ELF_TARG_VER)
 183                 return ENOEXEC;
 184
 185         return 0;
 186 }
 187
 188 static int
 189 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)
 190 {
 191         size_t map_len;
 192         vm_offset_t map_addr;
 193         int error, rv;
 194         size_t copy_len;
 195         vm_object_t object;
 196         vm_offset_t file_addr;
 197         vm_offset_t data_buf = 0;
 198
 199         GIANT_REQUIRED;
 200
 201         VOP_GETVOBJECT(vp, &object);
 202         error = 0;
 203
 204         /*
 205          * It's necessary to fail if the filsz + offset taken from the
 206          * header is greater than the actual file pager object's size.
 207          * If we were to allow this, then the vm_map_find() below would
 208          * walk right off the end of the file object and into the ether.
 209          *
 210          * While I'm here, might as well check for something else that
 211          * is invalid: filsz cannot be greater than memsz.
 212          */
 213         if ((off_t)filsz + offset > object->un_pager.vnp.vnp_size ||
 214             filsz > memsz) {
 215                 uprintf("elf_load_section: truncated ELF file\n");
 216                 return (ENOEXEC);
 217         }
 218
 219         map_addr = trunc_page((vm_offset_t)vmaddr);
 220         file_addr = trunc_page(offset);
 221
 222         /*
 223          * We have two choices.  We can either clear the data in the last page
 224          * of an oversized mapping, or we can start the anon mapping a page
 225          * early and copy the initialized data into that first page.  We
 226          * choose the second..
 227          */
 228         if (memsz > filsz)
 229                 map_len = trunc_page(offset+filsz) - file_addr;
 230         else
 231                 map_len = round_page(offset+filsz) - file_addr;
 232
 233         if (map_len != 0) {
 234                 vm_object_reference(object);
 235                 vm_map_lock(&vmspace->vm_map);
 236                 rv = vm_map_insert(&vmspace->vm_map,
 237                                       object,
 238                                       file_addr,        /* file offset */
 239                                       map_addr,         /* virtual start */
 240                                       map_addr + map_len,/* virtual end */
 241                                       prot,
 242                                       VM_PROT_ALL,
 243                                       MAP_COPY_ON_WRITE | MAP_PREFAULT);
 244                 vm_map_unlock(&vmspace->vm_map);
 245                 if (rv != KERN_SUCCESS) {
 246                         vm_object_deallocate(object);
 247                         return EINVAL;
 248                 }
 249
 250                 /* we can stop now if we've covered it all */
 251                 if (memsz == filsz) {
 252                         return 0;
 253                 }
 254         }
 255
 256
 257         /*
 258          * We have to get the remaining bit of the file into the first part
 259          * of the oversized map segment.  This is normally because the .data
 260          * segment in the file is extended to provide bss.  It's a neat idea
 261          * to try and save a page, but it's a pain in the behind to implement.
 262          */
 263         copy_len = (offset + filsz) - trunc_page(offset + filsz);
 264         map_addr = trunc_page((vm_offset_t)vmaddr + filsz);
 265         map_len = round_page((vm_offset_t)vmaddr + memsz) - map_addr;
 266
 267         /* This had damn well better be true! */
 268         if (map_len != 0) {
 269                 vm_map_lock(&vmspace->vm_map);
 270                 rv = vm_map_insert(&vmspace->vm_map, NULL, 0,
 271                                         map_addr, map_addr + map_len,
 272                                         VM_PROT_ALL, VM_PROT_ALL, 0);
 273                 vm_map_unlock(&vmspace->vm_map);
 274                 if (rv != KERN_SUCCESS) {
 275                         return EINVAL;
 276                 }
 277         }
 278
 279         if (copy_len != 0) {
 280                 vm_object_reference(object);
 281                 rv = vm_map_find(exec_map,
 282                                  object,
 283                                  trunc_page(offset + filsz),
 284                                  &data_buf,
 285                                  PAGE_SIZE,
 286                                  TRUE,
 287                                  VM_PROT_READ,
 288                                  VM_PROT_ALL,
 289                                  MAP_COPY_ON_WRITE | MAP_PREFAULT_PARTIAL);
 290                 if (rv != KERN_SUCCESS) {
 291                         vm_object_deallocate(object);
 292                         return EINVAL;
 293                 }
 294
 295                 /* send the page fragment to user space */
 296                 error = copyout((caddr_t)data_buf, (caddr_t)map_addr, copy_len);
 297                 vm_map_remove(exec_map, data_buf, data_buf + PAGE_SIZE);
 298                 if (error) {
 299                         return (error);
 300                 }
 301         }
 302
 303         /*
 304          * set it to the specified protection
 305          */
 306         vm_map_protect(&vmspace->vm_map, map_addr, map_addr + map_len,  prot,
 307                        FALSE);
 308
 309         return error;
 310 }
 311
 312 /*
 313  * Load the file "file" into memory.  It may be either a shared object
 314  * or an executable.
 315  *
 316  * The "addr" reference parameter is in/out.  On entry, it specifies
 317  * the address where a shared object should be loaded.  If the file is
 318  * an executable, this value is ignored.  On exit, "addr" specifies
 319  * where the file was actually loaded.
 320  *
 321  * The "entry" reference parameter is out only.  On exit, it specifies
 322  * the entry point for the loaded file.
 323  */
 324 static int
 325 elf_load_file(struct proc *p, const char *file, u_long *addr, u_long *entry)
 326 {
 327         struct {
 328                 struct nameidata nd;
 329                 struct vattr attr;
 330                 struct image_params image_params;
 331         } *tempdata;
 332         const Elf_Ehdr *hdr = NULL;
 333         const Elf_Phdr *phdr = NULL;
 334         struct nameidata *nd;
 335         struct vmspace *vmspace = p->p_vmspace;
 336         struct vattr *attr;
 337         struct image_params *imgp;
 338         vm_prot_t prot;
 339         u_long rbase;
 340         u_long base_addr = 0;
 341         int error, i, numsegs;
 342
 343         if (curthread->td_proc != p)
 344                 panic("elf_load_file - thread");        /* XXXKSE DIAGNOSTIC */
 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         /* XXXKSE */
 367         NDINIT(nd, LOOKUP, LOCKLEAF|FOLLOW, UIO_SYSSPACE, file, curthread);
 368
 369         if ((error = namei(nd)) != 0) {
 370                 nd->ni_vp = NULL;
 371                 goto fail;
 372         }
 373         NDFREE(nd, NDF_ONLY_PNBUF);
 374         imgp->vp = nd->ni_vp;
 375
 376         /*
 377          * Check permissions, modes, uid, etc on the file, and "open" it.
 378          */
 379         error = exec_check_permissions(imgp);
 380         if (error) {
 381                 VOP_UNLOCK(nd->ni_vp, 0, curthread); /* XXXKSE */
 382                 goto fail;
 383         }
 384
 385         error = exec_map_first_page(imgp);
 386         /*
 387          * Also make certain that the interpreter stays the same, so set
 388          * its VTEXT flag, too.
 389          */
 390         if (error == 0)
 391                 nd->ni_vp->v_flag |= VTEXT;
 392         VOP_UNLOCK(nd->ni_vp, 0, curthread); /* XXXKSE */
 393         if (error)
 394                 goto fail;
 395
 396         hdr = (const Elf_Ehdr *)imgp->image_header;
 397         if ((error = elf_check_header(hdr)) != 0)
 398                 goto fail;
 399         if (hdr->e_type == ET_DYN)
 400                 rbase = *addr;
 401         else if (hdr->e_type == ET_EXEC)
 402                 rbase = 0;
 403         else {
 404                 error = ENOEXEC;
 405                 goto fail;
 406         }
 407
 408         /* Only support headers that fit within first page for now */
 409         if ((hdr->e_phoff > PAGE_SIZE) ||
 410             (hdr->e_phoff + hdr->e_phentsize * hdr->e_phnum) > PAGE_SIZE) {
 411                 error = ENOEXEC;
 412                 goto fail;
 413         }
 414
 415         phdr = (const Elf_Phdr *)(imgp->image_header + hdr->e_phoff);
 416
 417         for (i = 0, numsegs = 0; i < hdr->e_phnum; i++) {
 418                 if (phdr[i].p_type == PT_LOAD) {        /* Loadable segment */
 419                         prot = 0;
 420                         if (phdr[i].p_flags & PF_X)
 421                                 prot |= VM_PROT_EXECUTE;
 422                         if (phdr[i].p_flags & PF_W)
 423                                 prot |= VM_PROT_WRITE;
 424                         if (phdr[i].p_flags & PF_R)
 425                                 prot |= VM_PROT_READ;
 426
 427                         if ((error = elf_load_section(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)) != 0)
 433                                 goto fail;
 434                         /*
 435                          * Establish the base address if this is the
 436                          * first segment.
 437                          */
 438                         if (numsegs == 0)
 439                                 base_addr = trunc_page(phdr[i].p_vaddr + rbase);
 440                         numsegs++;
 441                 }
 442         }
 443         *addr = base_addr;
 444         *entry=(unsigned long)hdr->e_entry + rbase;
 445
 446 fail:
 447         if (imgp->firstpage)
 448                 exec_unmap_first_page(imgp);
 449         if (imgp->image_header)
 450                 kmem_free_wakeup(exec_map, (vm_offset_t)imgp->image_header,
 451                         PAGE_SIZE);
 452         if (nd->ni_vp)
 453                 vrele(nd->ni_vp);
 454
 455         free(tempdata, M_TEMP);
 456
 457         return error;
 458 }
 459
 460 /*
 461  * non static, as it can be overridden by start_init()
 462  */
 463 #ifdef __ia64__
 464 int fallback_elf_brand = ELFOSABI_FREEBSD;
 465 #else
 466 int fallback_elf_brand = -1;
 467 #endif
 468 SYSCTL_INT(_kern, OID_AUTO, fallback_elf_brand, CTLFLAG_RW,
 469                 &fallback_elf_brand, -1,
 470                 "ELF brand of last resort");
 471
 472 static int
 473 exec_elf_imgact(struct image_params *imgp)
 474 {
 475         const Elf_Ehdr *hdr = (const Elf_Ehdr *) imgp->image_header;
 476         const Elf_Phdr *phdr;
 477         Elf_Auxargs *elf_auxargs = NULL;
 478         struct vmspace *vmspace;
 479         vm_prot_t prot;
 480         u_long text_size = 0, data_size = 0;
 481         u_long text_addr = 0, data_addr = 0;
 482         u_long addr, entry = 0, proghdr = 0;
 483         int error, i;
 484         const char *interp = NULL;
 485         Elf_Brandinfo *brand_info;
 486         char *path;
 487
 488         GIANT_REQUIRED;
 489
 490         /*
 491          * Do we have a valid ELF header ?
 492          */
 493         if (elf_check_header(hdr) != 0 || hdr->e_type != ET_EXEC)
 494                 return -1;
 495
 496         /*
 497          * From here on down, we return an errno, not -1, as we've
 498          * detected an ELF file.
 499          */
 500
 501         if ((hdr->e_phoff > PAGE_SIZE) ||
 502             (hdr->e_phoff + hdr->e_phentsize * hdr->e_phnum) > PAGE_SIZE) {
 503                 /* Only support headers in first page for now */
 504                 return ENOEXEC;
 505         }
 506         phdr = (const Elf_Phdr*)(imgp->image_header + hdr->e_phoff);
 507
 508         /*
 509          * From this point on, we may have resources that need to be freed.
 510          */
 511
 512         /*
 513          * Yeah, I'm paranoid.  There is every reason in the world to get
 514          * VTEXT now since from here on out, there are places we can have
 515          * a context switch.  Better safe than sorry; I really don't want
 516          * the file to change while it's being loaded.
 517          */
 518         mtx_lock(&imgp->vp->v_interlock);
 519         imgp->vp->v_flag |= VTEXT;
 520         mtx_unlock(&imgp->vp->v_interlock);
 521
 522         if ((error = exec_extract_strings(imgp)) != 0)
 523                 goto fail;
 524
 525         exec_new_vmspace(imgp);
 526
 527         vmspace = imgp->proc->p_vmspace;
 528
 529         for (i = 0; i < hdr->e_phnum; i++) {
 530                 switch(phdr[i].p_type) {
 531
 532                 case PT_LOAD:   /* Loadable segment */
 533                         prot = 0;
 534                         if (phdr[i].p_flags & PF_X)
 535                                 prot |= VM_PROT_EXECUTE;
 536                         if (phdr[i].p_flags & PF_W)
 537                                 prot |= VM_PROT_WRITE;
 538                         if (phdr[i].p_flags & PF_R)
 539                                 prot |= VM_PROT_READ;
 540
 541                         if ((error = elf_load_section(imgp->proc,
 542                                                      vmspace, imgp->vp,
 543                                                      phdr[i].p_offset,
 544                                                      (caddr_t)phdr[i].p_vaddr,
 545                                                      phdr[i].p_memsz,
 546                                                      phdr[i].p_filesz, prot)) != 0)
 547                                 goto fail;
 548
 549                         /*
 550                          * Is this .text or .data ??
 551                          *
 552                          * We only handle one each of those yet XXX
 553                          */
 554                         if (hdr->e_entry >= phdr[i].p_vaddr &&
 555                         hdr->e_entry <(phdr[i].p_vaddr+phdr[i].p_memsz)) {
 556                                 text_addr = trunc_page(phdr[i].p_vaddr);
 557                                 text_size = round_page(phdr[i].p_memsz +
 558                                                        phdr[i].p_vaddr -
 559                                                        text_addr);
 560                                 entry = (u_long)hdr->e_entry;
 561                         } else {
 562                                 data_addr = trunc_page(phdr[i].p_vaddr);
 563                                 data_size = round_page(phdr[i].p_memsz +
 564                                                        phdr[i].p_vaddr -
 565                                                        data_addr);
 566                         }
 567                         break;
 568                 case PT_INTERP: /* Path to interpreter */
 569                         if (phdr[i].p_filesz > MAXPATHLEN ||
 570                             phdr[i].p_offset + phdr[i].p_filesz > PAGE_SIZE) {
 571                                 error = ENOEXEC;
 572                                 goto fail;
 573                         }
 574                         interp = imgp->image_header + phdr[i].p_offset;
 575                         break;
 576                 case PT_PHDR:   /* Program header table info */
 577                         proghdr = phdr[i].p_vaddr;
 578                         break;
 579                 default:
 580                         break;
 581                 }
 582         }
 583
 584         vmspace->vm_tsize = text_size >> PAGE_SHIFT;
 585         vmspace->vm_taddr = (caddr_t)(uintptr_t)text_addr;
 586         vmspace->vm_dsize = data_size >> PAGE_SHIFT;
 587         vmspace->vm_daddr = (caddr_t)(uintptr_t)data_addr;
 588
 589         addr = ELF_RTLD_ADDR(vmspace);
 590
 591         imgp->entry_addr = entry;
 592
 593         brand_info = NULL;
 594
 595         /* We support three types of branding -- (1) the ELF EI_OSABI field
 596          * that SCO added to the ELF spec, (2) FreeBSD 3.x's traditional string
 597          * branding w/in the ELF header, and (3) path of the `interp_path'
 598          * field.  We should also look for an ".note.ABI-tag" ELF section now
 599          * in all Linux ELF binaries, FreeBSD 4.1+, and some NetBSD ones.
 600          */
 601
 602         /* If the executable has a brand, search for it in the brand list. */
 603         if (brand_info == NULL) {
 604                 for (i = 0;  i < MAX_BRANDS;  i++) {
 605                         Elf_Brandinfo *bi = elf_brand_list[i];
 606
 607                         if (bi != NULL &&
 608                             (hdr->e_ident[EI_OSABI] == bi->brand
 609                             || 0 ==
 610                             strncmp((const char *)&hdr->e_ident[OLD_EI_BRAND],
 611                             bi->compat_3_brand, strlen(bi->compat_3_brand)))) {
 612                                 brand_info = bi;
 613                                 break;
 614                         }
 615                 }
 616         }
 617
 618         /* Lacking a known brand, search for a recognized interpreter. */
 619         if (brand_info == NULL && interp != NULL) {
 620                 for (i = 0;  i < MAX_BRANDS;  i++) {
 621                         Elf_Brandinfo *bi = elf_brand_list[i];
 622
 623                         if (bi != NULL &&
 624                             strcmp(interp, bi->interp_path) == 0) {
 625                                 brand_info = bi;
 626                                 break;
 627                         }
 628                 }
 629         }
 630
 631         /* Lacking a recognized interpreter, try the default brand */
 632         if (brand_info == NULL) {
 633                 for (i = 0; i < MAX_BRANDS; i++) {
 634                         Elf_Brandinfo *bi = elf_brand_list[i];
 635
 636                         if (bi != NULL && fallback_elf_brand == bi->brand) {
 637                                 brand_info = bi;
 638                                 break;
 639                         }
 640                 }
 641         }
 642
 643         if (brand_info == NULL) {
 644                 uprintf("ELF binary type \"%u\" not known.\n",
 645                     hdr->e_ident[EI_OSABI]);
 646                 error = ENOEXEC;
 647                 goto fail;
 648         }
 649
 650         imgp->proc->p_sysent = brand_info->sysvec;
 651         if (interp != NULL) {
 652                 path = malloc(MAXPATHLEN, M_TEMP, M_WAITOK);
 653                 snprintf(path, MAXPATHLEN, "%s%s",
 654                          brand_info->emul_path, interp);
 655                 if ((error = elf_load_file(imgp->proc, path, &addr,
 656                                            &imgp->entry_addr)) != 0) {
 657                         if ((error = elf_load_file(imgp->proc, interp, &addr,
 658                                                    &imgp->entry_addr)) != 0) {
 659                                 uprintf("ELF interpreter %s not found\n", path);
 660                                 free(path, M_TEMP);
 661                                 goto fail;
 662                         }
 663                 }
 664                 free(path, M_TEMP);
 665         }
 666
 667         /*
 668          * Construct auxargs table (used by the fixup routine)
 669          */
 670         elf_auxargs = malloc(sizeof(Elf_Auxargs), M_TEMP, M_WAITOK);
 671         elf_auxargs->execfd = -1;
 672         elf_auxargs->phdr = proghdr;
 673         elf_auxargs->phent = hdr->e_phentsize;
 674         elf_auxargs->phnum = hdr->e_phnum;
 675         elf_auxargs->pagesz = PAGE_SIZE;
 676         elf_auxargs->base = addr;
 677         elf_auxargs->flags = 0;
 678         elf_auxargs->entry = entry;
 679         elf_auxargs->trace = elf_trace;
 680
 681         imgp->auxargs = elf_auxargs;
 682         imgp->interpreted = 0;
 683
 684 fail:
 685         return error;
 686 }
 687
 688 static int
 689 elf_freebsd_fixup(register_t **stack_base, struct image_params *imgp)
 690 {
 691         Elf_Auxargs *args = (Elf_Auxargs *)imgp->auxargs;
 692         register_t *pos;
 693
 694         pos = *stack_base + (imgp->argc + imgp->envc + 2);
 695
 696         if (args->trace) {
 697                 AUXARGS_ENTRY(pos, AT_DEBUG, 1);
 698         }
 699         if (args->execfd != -1) {
 700                 AUXARGS_ENTRY(pos, AT_EXECFD, args->execfd);
 701         }
 702         AUXARGS_ENTRY(pos, AT_PHDR, args->phdr);
 703         AUXARGS_ENTRY(pos, AT_PHENT, args->phent);
 704         AUXARGS_ENTRY(pos, AT_PHNUM, args->phnum);
 705         AUXARGS_ENTRY(pos, AT_PAGESZ, args->pagesz);
 706         AUXARGS_ENTRY(pos, AT_FLAGS, args->flags);
 707         AUXARGS_ENTRY(pos, AT_ENTRY, args->entry);
 708         AUXARGS_ENTRY(pos, AT_BASE, args->base);
 709         AUXARGS_ENTRY(pos, AT_NULL, 0);
 710
 711         free(imgp->auxargs, M_TEMP);
 712         imgp->auxargs = NULL;
 713
 714         (*stack_base)--;
 715         suword(*stack_base, (long) imgp->argc);
 716         return 0;
 717 }
 718
 719 /*
 720  * Code for generating ELF core dumps.
 721  */
 722
 723 typedef void (*segment_callback) __P((vm_map_entry_t, void *));
 724
 725 /* Closure for cb_put_phdr(). */
 726 struct phdr_closure {
 727         Elf_Phdr *phdr;         /* Program header to fill in */
 728         Elf_Off offset;         /* Offset of segment in core file */
 729 };
 730
 731 /* Closure for cb_size_segment(). */
 732 struct sseg_closure {
 733         int count;              /* Count of writable segments. */
 734         size_t size;            /* Total size of all writable segments. */
 735 };
 736
 737 static void cb_put_phdr __P((vm_map_entry_t, void *));
 738 static void cb_size_segment __P((vm_map_entry_t, void *));
 739 static void each_writable_segment __P((struct proc *, segment_callback,
 740     void *));
 741 static int elf_corehdr __P((struct thread *, struct vnode *, struct ucred *,
 742     int, void *, size_t));
 743 static void elf_puthdr __P((struct proc *, void *, size_t *,
 744     const prstatus_t *, const prfpregset_t *, const prpsinfo_t *, int));
 745 static void elf_putnote __P((void *, size_t *, const char *, int,
 746     const void *, size_t));
 747
 748 extern int osreldate;
 749
 750 int
 751 elf_coredump(td, vp, limit)
 752         struct thread *td;
 753         register struct vnode *vp;
 754         off_t limit;
 755 {
 756         register struct proc *p = td->td_proc;
 757         register struct ucred *cred = td->td_ucred;
 758         int error = 0;
 759         struct sseg_closure seginfo;
 760         void *hdr;
 761         size_t hdrsize;
 762
 763         /* Size the program segments. */
 764         seginfo.count = 0;
 765         seginfo.size = 0;
 766         each_writable_segment(p, cb_size_segment, &seginfo);
 767
 768         /*
 769          * Calculate the size of the core file header area by making
 770          * a dry run of generating it.  Nothing is written, but the
 771          * size is calculated.
 772          */
 773         hdrsize = 0;
 774         elf_puthdr((struct proc *)NULL, (void *)NULL, &hdrsize,
 775             (const prstatus_t *)NULL, (const prfpregset_t *)NULL,
 776             (const prpsinfo_t *)NULL, seginfo.count);
 777
 778         if (hdrsize + seginfo.size >= limit)
 779                 return (EFAULT);
 780
 781         /*
 782          * Allocate memory for building the header, fill it up,
 783          * and write it out.
 784          */
 785         hdr = malloc(hdrsize, M_TEMP, M_WAITOK);
 786         if (hdr == NULL) {
 787                 return EINVAL;
 788         }
 789         error = elf_corehdr(td, vp, cred, seginfo.count, hdr, hdrsize);
 790
 791         /* Write the contents of all of the writable segments. */
 792         if (error == 0) {
 793                 Elf_Phdr *php;
 794                 off_t offset;
 795                 int i;
 796
 797                 php = (Elf_Phdr *)((char *)hdr + sizeof(Elf_Ehdr)) + 1;
 798                 offset = hdrsize;
 799                 for (i = 0;  i < seginfo.count;  i++) {
 800                         error = vn_rdwr_inchunks(UIO_WRITE, vp,
 801                             (caddr_t)php->p_vaddr,
 802                             php->p_filesz, offset, UIO_USERSPACE,
 803                             IO_UNIT | IO_DIRECT, cred, (int *)NULL, curthread); /* XXXKSE */
 804                         if (error != 0)
 805                                 break;
 806                         offset += php->p_filesz;
 807                         php++;
 808                 }
 809         }
 810         free(hdr, M_TEMP);
 811
 812         return error;
 813 }
 814
 815 /*
 816  * A callback for each_writable_segment() to write out the segment's
 817  * program header entry.
 818  */
 819 static void
 820 cb_put_phdr(entry, closure)
 821         vm_map_entry_t entry;
 822         void *closure;
 823 {
 824         struct phdr_closure *phc = (struct phdr_closure *)closure;
 825         Elf_Phdr *phdr = phc->phdr;
 826
 827         phc->offset = round_page(phc->offset);
 828
 829         phdr->p_type = PT_LOAD;
 830         phdr->p_offset = phc->offset;
 831         phdr->p_vaddr = entry->start;
 832         phdr->p_paddr = 0;
 833         phdr->p_filesz = phdr->p_memsz = entry->end - entry->start;
 834         phdr->p_align = PAGE_SIZE;
 835         phdr->p_flags = 0;
 836         if (entry->protection & VM_PROT_READ)
 837                 phdr->p_flags |= PF_R;
 838         if (entry->protection & VM_PROT_WRITE)
 839                 phdr->p_flags |= PF_W;
 840         if (entry->protection & VM_PROT_EXECUTE)
 841                 phdr->p_flags |= PF_X;
 842
 843         phc->offset += phdr->p_filesz;
 844         phc->phdr++;
 845 }
 846
 847 /*
 848  * A callback for each_writable_segment() to gather information about
 849  * the number of segments and their total size.
 850  */
 851 static void
 852 cb_size_segment(entry, closure)
 853         vm_map_entry_t entry;
 854         void *closure;
 855 {
 856         struct sseg_closure *ssc = (struct sseg_closure *)closure;
 857
 858         ssc->count++;
 859         ssc->size += entry->end - entry->start;
 860 }
 861
 862 /*
 863  * For each writable segment in the process's memory map, call the given
 864  * function with a pointer to the map entry and some arbitrary
 865  * caller-supplied data.
 866  */
 867 static void
 868 each_writable_segment(p, func, closure)
 869         struct proc *p;
 870         segment_callback func;
 871         void *closure;
 872 {
 873         vm_map_t map = &p->p_vmspace->vm_map;
 874         vm_map_entry_t entry;
 875
 876         for (entry = map->header.next;  entry != &map->header;
 877             entry = entry->next) {
 878                 vm_object_t obj;
 879
 880                 if ((entry->eflags & MAP_ENTRY_IS_SUB_MAP) ||
 881                     (entry->protection & (VM_PROT_READ|VM_PROT_WRITE)) !=
 882                     (VM_PROT_READ|VM_PROT_WRITE))
 883                         continue;
 884
 885                 /*
 886                 ** Dont include memory segment in the coredump if
 887                 ** MAP_NOCORE is set in mmap(2) or MADV_NOCORE in
 888                 ** madvise(2).
 889                 */
 890                 if (entry->eflags & MAP_ENTRY_NOCOREDUMP)
 891                         continue;
 892
 893                 if ((obj = entry->object.vm_object) == NULL)
 894                         continue;
 895
 896                 /* Find the deepest backing object. */
 897                 while (obj->backing_object != NULL)
 898                         obj = obj->backing_object;
 899
 900                 /* Ignore memory-mapped devices and such things. */
 901                 if (obj->type != OBJT_DEFAULT &&
 902                     obj->type != OBJT_SWAP &&
 903                     obj->type != OBJT_VNODE)
 904                         continue;
 905
 906                 (*func)(entry, closure);
 907         }
 908 }
 909
 910 /*
 911  * Write the core file header to the file, including padding up to
 912  * the page boundary.
 913  */
 914 static int
 915 elf_corehdr(td, vp, cred, numsegs, hdr, hdrsize)
 916         struct thread *td;
 917         struct vnode *vp;
 918         struct ucred *cred;
 919         int numsegs;
 920         size_t hdrsize;
 921         void *hdr;
 922 {
 923         struct {
 924                 prstatus_t status;
 925                 prfpregset_t fpregset;
 926                 prpsinfo_t psinfo;
 927         } *tempdata;
 928         struct proc *p = td->td_proc;
 929         size_t off;
 930         prstatus_t *status;
 931         prfpregset_t *fpregset;
 932         prpsinfo_t *psinfo;
 933
 934         tempdata = malloc(sizeof(*tempdata), M_TEMP, M_ZERO | M_WAITOK);
 935         status = &tempdata->status;
 936         fpregset = &tempdata->fpregset;
 937         psinfo = &tempdata->psinfo;
 938
 939         /* Gather the information for the header. */
 940         status->pr_version = PRSTATUS_VERSION;
 941         status->pr_statussz = sizeof(prstatus_t);
 942         status->pr_gregsetsz = sizeof(gregset_t);
 943         status->pr_fpregsetsz = sizeof(fpregset_t);
 944         status->pr_osreldate = osreldate;
 945         status->pr_cursig = p->p_sig;
 946         status->pr_pid = p->p_pid;
 947         fill_regs(td, &status->pr_reg);
 948
 949         fill_fpregs(td, fpregset);
 950
 951         psinfo->pr_version = PRPSINFO_VERSION;
 952         psinfo->pr_psinfosz = sizeof(prpsinfo_t);
 953         strncpy(psinfo->pr_fname, p->p_comm, sizeof(psinfo->pr_fname) - 1);
 954
 955         /* XXX - We don't fill in the command line arguments properly yet. */
 956         strncpy(psinfo->pr_psargs, p->p_comm, PRARGSZ);
 957
 958         /* Fill in the header. */
 959         bzero(hdr, hdrsize);
 960         off = 0;
 961         elf_puthdr(p, hdr, &off, status, fpregset, psinfo, numsegs);
 962
 963         free(tempdata, M_TEMP);
 964
 965         /* Write it to the core file. */
 966         return vn_rdwr_inchunks(UIO_WRITE, vp, hdr, hdrsize, (off_t)0,
 967             UIO_SYSSPACE, IO_UNIT | IO_DIRECT, cred, NULL, td); /* XXXKSE */
 968 }
 969
 970 static void
 971 elf_puthdr(struct proc *p, void *dst, size_t *off, const prstatus_t *status,
 972     const prfpregset_t *fpregset, const prpsinfo_t *psinfo, int numsegs)
 973 {
 974         size_t ehoff;
 975         size_t phoff;
 976         size_t noteoff;
 977         size_t notesz;
 978
 979         ehoff = *off;
 980         *off += sizeof(Elf_Ehdr);
 981
 982         phoff = *off;
 983         *off += (numsegs + 1) * sizeof(Elf_Phdr);
 984
 985         noteoff = *off;
 986         elf_putnote(dst, off, "FreeBSD", NT_PRSTATUS, status,
 987             sizeof *status);
 988         elf_putnote(dst, off, "FreeBSD", NT_FPREGSET, fpregset,
 989             sizeof *fpregset);
 990         elf_putnote(dst, off, "FreeBSD", NT_PRPSINFO, psinfo,
 991             sizeof *psinfo);
 992         notesz = *off - noteoff;
 993
 994         /* Align up to a page boundary for the program segments. */
 995         *off = round_page(*off);
 996
 997         if (dst != NULL) {
 998                 Elf_Ehdr *ehdr;
 999                 Elf_Phdr *phdr;
1000                 struct phdr_closure phc;
1001
1002                 /*
1003                  * Fill in the ELF header.
1004                  */
1005                 ehdr = (Elf_Ehdr *)((char *)dst + ehoff);
1006                 ehdr->e_ident[EI_MAG0] = ELFMAG0;
1007                 ehdr->e_ident[EI_MAG1] = ELFMAG1;
1008                 ehdr->e_ident[EI_MAG2] = ELFMAG2;
1009                 ehdr->e_ident[EI_MAG3] = ELFMAG3;
1010                 ehdr->e_ident[EI_CLASS] = ELF_CLASS;
1011                 ehdr->e_ident[EI_DATA] = ELF_DATA;
1012                 ehdr->e_ident[EI_VERSION] = EV_CURRENT;
1013                 ehdr->e_ident[EI_OSABI] = ELFOSABI_FREEBSD;
1014                 ehdr->e_ident[EI_ABIVERSION] = 0;
1015                 ehdr->e_ident[EI_PAD] = 0;
1016                 ehdr->e_type = ET_CORE;
1017                 ehdr->e_machine = ELF_ARCH;
1018                 ehdr->e_version = EV_CURRENT;
1019                 ehdr->e_entry = 0;
1020                 ehdr->e_phoff = phoff;
1021                 ehdr->e_flags = 0;
1022                 ehdr->e_ehsize = sizeof(Elf_Ehdr);
1023                 ehdr->e_phentsize = sizeof(Elf_Phdr);
1024                 ehdr->e_phnum = numsegs + 1;
1025                 ehdr->e_shentsize = sizeof(Elf_Shdr);
1026                 ehdr->e_shnum = 0;
1027                 ehdr->e_shstrndx = SHN_UNDEF;
1028
1029                 /*
1030                  * Fill in the program header entries.
1031                  */
1032                 phdr = (Elf_Phdr *)((char *)dst + phoff);
1033
1034                 /* The note segement. */
1035                 phdr->p_type = PT_NOTE;
1036                 phdr->p_offset = noteoff;
1037                 phdr->p_vaddr = 0;
1038                 phdr->p_paddr = 0;
1039                 phdr->p_filesz = notesz;
1040                 phdr->p_memsz = 0;
1041                 phdr->p_flags = 0;
1042                 phdr->p_align = 0;
1043                 phdr++;
1044
1045                 /* All the writable segments from the program. */
1046                 phc.phdr = phdr;
1047                 phc.offset = *off;
1048                 each_writable_segment(p, cb_put_phdr, &phc);
1049         }
1050 }
1051
1052 static void
1053 elf_putnote(void *dst, size_t *off, const char *name, int type,
1054     const void *desc, size_t descsz)
1055 {
1056         Elf_Note note;
1057
1058         note.n_namesz = strlen(name) + 1;
1059         note.n_descsz = descsz;
1060         note.n_type = type;
1061         if (dst != NULL)
1062                 bcopy(&note, (char *)dst + *off, sizeof note);
1063         *off += sizeof note;
1064         if (dst != NULL)
1065                 bcopy(name, (char *)dst + *off, note.n_namesz);
1066         *off += roundup2(note.n_namesz, sizeof(Elf_Size));
1067         if (dst != NULL)
1068                 bcopy(desc, (char *)dst + *off, note.n_descsz);
1069         *off += roundup2(note.n_descsz, sizeof(Elf_Size));
1070 }
1071
1072 /*
1073  * Tell kern_execve.c about it, with a little help from the linker.
1074  */
1075 static struct execsw elf_execsw = {exec_elf_imgact, "ELF"};
1076 EXEC_SET(elf, elf_execsw);