1260684Skaiw/*- 2260684Skaiw * Copyright (c) 2006-2011 Joseph Koshy 3260684Skaiw * All rights reserved. 4260684Skaiw * 5260684Skaiw * Redistribution and use in source and binary forms, with or without 6260684Skaiw * modification, are permitted provided that the following conditions 7260684Skaiw * are met: 8260684Skaiw * 1. Redistributions of source code must retain the above copyright 9260684Skaiw * notice, this list of conditions and the following disclaimer. 10260684Skaiw * 2. Redistributions in binary form must reproduce the above copyright 11260684Skaiw * notice, this list of conditions and the following disclaimer in the 12260684Skaiw * documentation and/or other materials provided with the distribution. 13260684Skaiw * 14260684Skaiw * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15260684Skaiw * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16260684Skaiw * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17260684Skaiw * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18260684Skaiw * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19260684Skaiw * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20260684Skaiw * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21260684Skaiw * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22260684Skaiw * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23260684Skaiw * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24260684Skaiw * SUCH DAMAGE. 25260684Skaiw */ 26260684Skaiw 27260684Skaiw#include <sys/param.h> 28260684Skaiw#include <sys/stat.h> 29260684Skaiw 30260684Skaiw#include <assert.h> 31260684Skaiw#include <errno.h> 32260684Skaiw#include <gelf.h> 33260684Skaiw#include <libelf.h> 34260684Skaiw#include <stdlib.h> 35260684Skaiw#include <string.h> 36260684Skaiw#include <unistd.h> 37260684Skaiw 38260684Skaiw#include "_libelf.h" 39260684Skaiw 40260684Skaiw#if ELFTC_HAVE_MMAP 41260684Skaiw#include <sys/mman.h> 42260684Skaiw#endif 43260684Skaiw 44367466SdimELFTC_VCSID("$Id: elf_update.c 3763 2019-06-28 21:43:27Z emaste $"); 45260684Skaiw 46260684Skaiw/* 47260684Skaiw * Layout strategy: 48260684Skaiw * 49260684Skaiw * - Case 1: ELF_F_LAYOUT is asserted 50260684Skaiw * In this case the application has full control over where the 51260684Skaiw * section header table, program header table, and section data 52260684Skaiw * will reside. The library only perform error checks. 53260684Skaiw * 54260684Skaiw * - Case 2: ELF_F_LAYOUT is not asserted 55260684Skaiw * 56260684Skaiw * The library will do the object layout using the following 57260684Skaiw * ordering: 58260684Skaiw * - The executable header is placed first, are required by the 59260684Skaiw * ELF specification. 60260684Skaiw * - The program header table is placed immediately following the 61260684Skaiw * executable header. 62260684Skaiw * - Section data, if any, is placed after the program header 63260684Skaiw * table, aligned appropriately. 64260684Skaiw * - The section header table, if needed, is placed last. 65260684Skaiw * 66260684Skaiw * There are two sub-cases to be taken care of: 67260684Skaiw * 68260684Skaiw * - Case 2a: e->e_cmd == ELF_C_READ or ELF_C_RDWR 69260684Skaiw * 70260684Skaiw * In this sub-case, the underlying ELF object may already have 71260684Skaiw * content in it, which the application may have modified. The 72260684Skaiw * library will retrieve content from the existing object as 73260684Skaiw * needed. 74260684Skaiw * 75260684Skaiw * - Case 2b: e->e_cmd == ELF_C_WRITE 76260684Skaiw * 77260684Skaiw * The ELF object is being created afresh in this sub-case; 78260684Skaiw * there is no pre-existing content in the underlying ELF 79260684Skaiw * object. 80260684Skaiw */ 81260684Skaiw 82260684Skaiw/* 83260684Skaiw * The types of extents in an ELF object. 84260684Skaiw */ 85260684Skaiwenum elf_extent { 86260684Skaiw ELF_EXTENT_EHDR, 87260684Skaiw ELF_EXTENT_PHDR, 88260684Skaiw ELF_EXTENT_SECTION, 89260684Skaiw ELF_EXTENT_SHDR 90260684Skaiw}; 91260684Skaiw 92260684Skaiw/* 93260684Skaiw * A extent descriptor, used when laying out an ELF object. 94260684Skaiw */ 95260684Skaiwstruct _Elf_Extent { 96260684Skaiw SLIST_ENTRY(_Elf_Extent) ex_next; 97260684Skaiw uint64_t ex_start; /* Start of the region. */ 98260684Skaiw uint64_t ex_size; /* The size of the region. */ 99260684Skaiw enum elf_extent ex_type; /* Type of region. */ 100260684Skaiw void *ex_desc; /* Associated descriptor. */ 101260684Skaiw}; 102260684Skaiw 103260684SkaiwSLIST_HEAD(_Elf_Extent_List, _Elf_Extent); 104260684Skaiw 105260684Skaiw/* 106260684Skaiw * Compute the extents of a section, by looking at the data 107260684Skaiw * descriptors associated with it. The function returns 1 108260684Skaiw * if successful, or zero if an error was detected. 109260684Skaiw */ 110260684Skaiwstatic int 111260684Skaiw_libelf_compute_section_extents(Elf *e, Elf_Scn *s, off_t rc) 112260684Skaiw{ 113260684Skaiw Elf_Data *d; 114260684Skaiw size_t fsz, msz; 115276371Semaste int ec, elftype; 116260684Skaiw uint32_t sh_type; 117260684Skaiw uint64_t d_align; 118260684Skaiw Elf32_Shdr *shdr32; 119260684Skaiw Elf64_Shdr *shdr64; 120260684Skaiw struct _Libelf_Data *ld; 121260684Skaiw uint64_t scn_size, scn_alignment; 122260684Skaiw uint64_t sh_align, sh_entsize, sh_offset, sh_size; 123260684Skaiw 124260684Skaiw ec = e->e_class; 125260684Skaiw 126260684Skaiw shdr32 = &s->s_shdr.s_shdr32; 127260684Skaiw shdr64 = &s->s_shdr.s_shdr64; 128260684Skaiw if (ec == ELFCLASS32) { 129260684Skaiw sh_type = shdr32->sh_type; 130260684Skaiw sh_align = (uint64_t) shdr32->sh_addralign; 131260684Skaiw sh_entsize = (uint64_t) shdr32->sh_entsize; 132260684Skaiw sh_offset = (uint64_t) shdr32->sh_offset; 133260684Skaiw sh_size = (uint64_t) shdr32->sh_size; 134260684Skaiw } else { 135260684Skaiw sh_type = shdr64->sh_type; 136260684Skaiw sh_align = shdr64->sh_addralign; 137260684Skaiw sh_entsize = shdr64->sh_entsize; 138260684Skaiw sh_offset = shdr64->sh_offset; 139260684Skaiw sh_size = shdr64->sh_size; 140260684Skaiw } 141260684Skaiw 142260684Skaiw assert(sh_type != SHT_NULL && sh_type != SHT_NOBITS); 143260684Skaiw 144260684Skaiw elftype = _libelf_xlate_shtype(sh_type); 145367466Sdim if (elftype < ELF_T_FIRST || elftype > ELF_T_LAST) { 146260684Skaiw LIBELF_SET_ERROR(SECTION, 0); 147260684Skaiw return (0); 148260684Skaiw } 149260684Skaiw 150260684Skaiw if (sh_align == 0) 151260684Skaiw sh_align = _libelf_falign(elftype, ec); 152260684Skaiw 153260684Skaiw /* 154260684Skaiw * Compute the section's size and alignment using the data 155260684Skaiw * descriptors associated with the section. 156260684Skaiw */ 157260684Skaiw if (STAILQ_EMPTY(&s->s_data)) { 158260684Skaiw /* 159260684Skaiw * The section's content (if any) has not been read in 160260684Skaiw * yet. If section is not dirty marked dirty, we can 161260684Skaiw * reuse the values in the 'sh_size' and 'sh_offset' 162260684Skaiw * fields of the section header. 163260684Skaiw */ 164260684Skaiw if ((s->s_flags & ELF_F_DIRTY) == 0) { 165260684Skaiw /* 166260684Skaiw * If the library is doing the layout, then we 167260684Skaiw * compute the new start offset for the 168260684Skaiw * section based on the current offset and the 169260684Skaiw * section's alignment needs. 170260684Skaiw * 171260684Skaiw * If the application is doing the layout, we 172260684Skaiw * can use the value in the 'sh_offset' field 173260684Skaiw * in the section header directly. 174260684Skaiw */ 175260684Skaiw if (e->e_flags & ELF_F_LAYOUT) 176260684Skaiw goto updatedescriptor; 177260684Skaiw else 178260684Skaiw goto computeoffset; 179260684Skaiw } 180260684Skaiw 181260684Skaiw /* 182260684Skaiw * Otherwise, we need to bring in the section's data 183260684Skaiw * from the underlying ELF object. 184260684Skaiw */ 185260684Skaiw if (e->e_cmd != ELF_C_WRITE && elf_getdata(s, NULL) == NULL) 186260684Skaiw return (0); 187260684Skaiw } 188260684Skaiw 189260684Skaiw /* 190260684Skaiw * Loop through the section's data descriptors. 191260684Skaiw */ 192260684Skaiw scn_size = 0L; 193260684Skaiw scn_alignment = 0; 194260684Skaiw STAILQ_FOREACH(ld, &s->s_data, d_next) { 195260684Skaiw 196260684Skaiw d = &ld->d_data; 197260684Skaiw 198260684Skaiw /* 199260684Skaiw * The data buffer's type is known. 200260684Skaiw */ 201260684Skaiw if (d->d_type >= ELF_T_NUM) { 202260684Skaiw LIBELF_SET_ERROR(DATA, 0); 203260684Skaiw return (0); 204260684Skaiw } 205260684Skaiw 206260684Skaiw /* 207260684Skaiw * The data buffer's version is supported. 208260684Skaiw */ 209260684Skaiw if (d->d_version != e->e_version) { 210260684Skaiw LIBELF_SET_ERROR(VERSION, 0); 211260684Skaiw return (0); 212260684Skaiw } 213260684Skaiw 214260684Skaiw /* 215260684Skaiw * The buffer's alignment is non-zero and a power of 216260684Skaiw * two. 217260684Skaiw */ 218260684Skaiw if ((d_align = d->d_align) == 0 || 219260684Skaiw (d_align & (d_align - 1))) { 220260684Skaiw LIBELF_SET_ERROR(DATA, 0); 221260684Skaiw return (0); 222260684Skaiw } 223260684Skaiw 224260684Skaiw /* 225367466Sdim * The data buffer's ELF type, ELF class and ELF version 226367466Sdim * should be supported. 227367466Sdim */ 228367466Sdim if ((msz = _libelf_msize(d->d_type, ec, e->e_version)) == 0) 229367466Sdim return (0); 230367466Sdim 231367466Sdim /* 232260684Skaiw * The buffer's size should be a multiple of the 233260684Skaiw * memory size of the underlying type. 234260684Skaiw */ 235260684Skaiw if (d->d_size % msz) { 236260684Skaiw LIBELF_SET_ERROR(DATA, 0); 237260684Skaiw return (0); 238260684Skaiw } 239260684Skaiw 240260684Skaiw /* 241260684Skaiw * If the application is controlling layout, then the 242260684Skaiw * d_offset field should be compatible with the 243260684Skaiw * buffer's specified alignment. 244260684Skaiw */ 245260684Skaiw if ((e->e_flags & ELF_F_LAYOUT) && 246260684Skaiw (d->d_off & (d_align - 1))) { 247260684Skaiw LIBELF_SET_ERROR(LAYOUT, 0); 248260684Skaiw return (0); 249260684Skaiw } 250260684Skaiw 251260684Skaiw /* 252260684Skaiw * Compute the section's size. 253260684Skaiw */ 254260684Skaiw if (e->e_flags & ELF_F_LAYOUT) { 255260684Skaiw if ((uint64_t) d->d_off + d->d_size > scn_size) 256260684Skaiw scn_size = d->d_off + d->d_size; 257260684Skaiw } else { 258260684Skaiw scn_size = roundup2(scn_size, d->d_align); 259260684Skaiw d->d_off = scn_size; 260260684Skaiw fsz = _libelf_fsize(d->d_type, ec, d->d_version, 261276371Semaste (size_t) d->d_size / msz); 262260684Skaiw scn_size += fsz; 263260684Skaiw } 264260684Skaiw 265260684Skaiw /* 266260684Skaiw * The section's alignment is the maximum alignment 267260684Skaiw * needed for its data buffers. 268260684Skaiw */ 269260684Skaiw if (d_align > scn_alignment) 270260684Skaiw scn_alignment = d_align; 271260684Skaiw } 272260684Skaiw 273260684Skaiw 274260684Skaiw /* 275260684Skaiw * If the application is requesting full control over the 276260684Skaiw * layout of the section, check the section's specified size, 277260684Skaiw * offsets and alignment for sanity. 278260684Skaiw */ 279260684Skaiw if (e->e_flags & ELF_F_LAYOUT) { 280282918Semaste if (scn_alignment > sh_align || 281282918Semaste sh_offset % sh_align || 282282918Semaste sh_size < scn_size || 283282918Semaste sh_offset % _libelf_falign(elftype, ec)) { 284260684Skaiw LIBELF_SET_ERROR(LAYOUT, 0); 285260684Skaiw return (0); 286260684Skaiw } 287260684Skaiw goto updatedescriptor; 288260684Skaiw } 289260684Skaiw 290260684Skaiw /* 291260684Skaiw * Otherwise, compute the values in the section header. 292260684Skaiw * 293260684Skaiw * The section alignment is the maximum alignment for any of 294260684Skaiw * its contained data descriptors. 295260684Skaiw */ 296260684Skaiw if (scn_alignment > sh_align) 297260684Skaiw sh_align = scn_alignment; 298260684Skaiw 299260684Skaiw /* 300260684Skaiw * If the section entry size is zero, try and fill in an 301260684Skaiw * appropriate entry size. Per the elf(5) manual page 302260684Skaiw * sections without fixed-size entries should have their 303260684Skaiw * 'sh_entsize' field set to zero. 304260684Skaiw */ 305260684Skaiw if (sh_entsize == 0 && 306260684Skaiw (sh_entsize = _libelf_fsize(elftype, ec, e->e_version, 307260684Skaiw (size_t) 1)) == 1) 308260684Skaiw sh_entsize = 0; 309260684Skaiw 310260684Skaiw sh_size = scn_size; 311260684Skaiw 312260684Skaiwcomputeoffset: 313260684Skaiw /* 314260684Skaiw * Compute the new offset for the section based on 315260684Skaiw * the section's alignment needs. 316260684Skaiw */ 317276371Semaste sh_offset = roundup((uint64_t) rc, sh_align); 318260684Skaiw 319260684Skaiw /* 320260684Skaiw * Update the section header. 321260684Skaiw */ 322260684Skaiw if (ec == ELFCLASS32) { 323260684Skaiw shdr32->sh_addralign = (uint32_t) sh_align; 324260684Skaiw shdr32->sh_entsize = (uint32_t) sh_entsize; 325260684Skaiw shdr32->sh_offset = (uint32_t) sh_offset; 326260684Skaiw shdr32->sh_size = (uint32_t) sh_size; 327260684Skaiw } else { 328260684Skaiw shdr64->sh_addralign = sh_align; 329260684Skaiw shdr64->sh_entsize = sh_entsize; 330260684Skaiw shdr64->sh_offset = sh_offset; 331260684Skaiw shdr64->sh_size = sh_size; 332260684Skaiw } 333260684Skaiw 334260684Skaiwupdatedescriptor: 335260684Skaiw /* 336260684Skaiw * Update the section descriptor. 337260684Skaiw */ 338260684Skaiw s->s_size = sh_size; 339260684Skaiw s->s_offset = sh_offset; 340260684Skaiw 341260684Skaiw return (1); 342260684Skaiw} 343260684Skaiw 344260684Skaiw/* 345260684Skaiw * Free a list of extent descriptors. 346260684Skaiw */ 347260684Skaiw 348260684Skaiwstatic void 349260684Skaiw_libelf_release_extents(struct _Elf_Extent_List *extents) 350260684Skaiw{ 351260684Skaiw struct _Elf_Extent *ex; 352260684Skaiw 353260684Skaiw while ((ex = SLIST_FIRST(extents)) != NULL) { 354260684Skaiw SLIST_REMOVE_HEAD(extents, ex_next); 355260684Skaiw free(ex); 356260684Skaiw } 357260684Skaiw} 358260684Skaiw 359260684Skaiw/* 360260684Skaiw * Check if an extent 's' defined by [start..start+size) is free. 361260684Skaiw * This routine assumes that the given extent list is sorted in order 362260684Skaiw * of ascending extent offsets. 363260684Skaiw */ 364260684Skaiw 365260684Skaiwstatic int 366260684Skaiw_libelf_extent_is_unused(struct _Elf_Extent_List *extents, 367260684Skaiw const uint64_t start, const uint64_t size, struct _Elf_Extent **prevt) 368260684Skaiw{ 369260684Skaiw uint64_t tmax, tmin; 370260684Skaiw struct _Elf_Extent *t, *pt; 371260684Skaiw const uint64_t smax = start + size; 372260684Skaiw 373260684Skaiw /* First, look for overlaps with existing extents. */ 374260684Skaiw pt = NULL; 375260684Skaiw SLIST_FOREACH(t, extents, ex_next) { 376260684Skaiw tmin = t->ex_start; 377260684Skaiw tmax = tmin + t->ex_size; 378260684Skaiw 379260684Skaiw if (tmax <= start) { 380260684Skaiw /* 381260684Skaiw * 't' lies entirely before 's': ...| t |...| s |... 382260684Skaiw */ 383260684Skaiw pt = t; 384260684Skaiw continue; 385260684Skaiw } else if (smax <= tmin) { 386260684Skaiw /* 387260684Skaiw * 's' lies entirely before 't', and after 'pt': 388260684Skaiw * ...| pt |...| s |...| t |... 389260684Skaiw */ 390260684Skaiw assert(pt == NULL || 391260684Skaiw pt->ex_start + pt->ex_size <= start); 392260684Skaiw break; 393260684Skaiw } else 394260684Skaiw /* 's' and 't' overlap. */ 395260684Skaiw return (0); 396260684Skaiw } 397260684Skaiw 398260684Skaiw if (prevt) 399260684Skaiw *prevt = pt; 400260684Skaiw return (1); 401260684Skaiw} 402260684Skaiw 403260684Skaiw/* 404260684Skaiw * Insert an extent into the list of extents. 405260684Skaiw */ 406260684Skaiw 407260684Skaiwstatic int 408260684Skaiw_libelf_insert_extent(struct _Elf_Extent_List *extents, int type, 409260684Skaiw uint64_t start, uint64_t size, void *desc) 410260684Skaiw{ 411260684Skaiw struct _Elf_Extent *ex, *prevt; 412260684Skaiw 413260684Skaiw assert(type >= ELF_EXTENT_EHDR && type <= ELF_EXTENT_SHDR); 414260684Skaiw 415260684Skaiw prevt = NULL; 416260684Skaiw 417260684Skaiw /* 418260684Skaiw * If the requested range overlaps with an existing extent, 419260684Skaiw * signal an error. 420260684Skaiw */ 421260684Skaiw if (!_libelf_extent_is_unused(extents, start, size, &prevt)) { 422260684Skaiw LIBELF_SET_ERROR(LAYOUT, 0); 423260684Skaiw return (0); 424260684Skaiw } 425260684Skaiw 426260684Skaiw /* Allocate and fill in a new extent descriptor. */ 427260684Skaiw if ((ex = malloc(sizeof(struct _Elf_Extent))) == NULL) { 428260684Skaiw LIBELF_SET_ERROR(RESOURCE, errno); 429260684Skaiw return (0); 430260684Skaiw } 431260684Skaiw ex->ex_start = start; 432260684Skaiw ex->ex_size = size; 433260684Skaiw ex->ex_desc = desc; 434260684Skaiw ex->ex_type = type; 435260684Skaiw 436260684Skaiw /* Insert the region descriptor into the list. */ 437260684Skaiw if (prevt) 438260684Skaiw SLIST_INSERT_AFTER(prevt, ex, ex_next); 439260684Skaiw else 440260684Skaiw SLIST_INSERT_HEAD(extents, ex, ex_next); 441260684Skaiw return (1); 442260684Skaiw} 443260684Skaiw 444260684Skaiw/* 445260684Skaiw * Recompute section layout. 446260684Skaiw */ 447260684Skaiw 448260684Skaiwstatic off_t 449260684Skaiw_libelf_resync_sections(Elf *e, off_t rc, struct _Elf_Extent_List *extents) 450260684Skaiw{ 451260684Skaiw int ec; 452260684Skaiw Elf_Scn *s; 453260684Skaiw size_t sh_type; 454260684Skaiw 455260684Skaiw ec = e->e_class; 456260684Skaiw 457260684Skaiw /* 458260684Skaiw * Make a pass through sections, computing the extent of each 459260684Skaiw * section. 460260684Skaiw */ 461367466Sdim RB_FOREACH(s, scntree, &e->e_u.e_elf.e_scn) { 462260684Skaiw if (ec == ELFCLASS32) 463260684Skaiw sh_type = s->s_shdr.s_shdr32.sh_type; 464260684Skaiw else 465260684Skaiw sh_type = s->s_shdr.s_shdr64.sh_type; 466260684Skaiw 467260684Skaiw if (sh_type == SHT_NOBITS || sh_type == SHT_NULL) 468260684Skaiw continue; 469260684Skaiw 470260684Skaiw if (_libelf_compute_section_extents(e, s, rc) == 0) 471260684Skaiw return ((off_t) -1); 472260684Skaiw 473260684Skaiw if (s->s_size == 0) 474260684Skaiw continue; 475260684Skaiw 476260684Skaiw if (!_libelf_insert_extent(extents, ELF_EXTENT_SECTION, 477260684Skaiw s->s_offset, s->s_size, s)) 478260684Skaiw return ((off_t) -1); 479260684Skaiw 480260684Skaiw if ((size_t) rc < s->s_offset + s->s_size) 481276371Semaste rc = (off_t) (s->s_offset + s->s_size); 482260684Skaiw } 483260684Skaiw 484260684Skaiw return (rc); 485260684Skaiw} 486260684Skaiw 487260684Skaiw/* 488260684Skaiw * Recompute the layout of the ELF object and update the internal data 489260684Skaiw * structures associated with the ELF descriptor. 490260684Skaiw * 491260684Skaiw * Returns the size in bytes the ELF object would occupy in its file 492260684Skaiw * representation. 493260684Skaiw * 494260684Skaiw * After a successful call to this function, the following structures 495260684Skaiw * are updated: 496260684Skaiw * 497260684Skaiw * - The ELF header is updated. 498260684Skaiw * - All extents in the ELF object are sorted in order of ascending 499260684Skaiw * addresses. Sections have their section header table entries 500260684Skaiw * updated. An error is signalled if an overlap was detected among 501260684Skaiw * extents. 502260684Skaiw * - Data descriptors associated with sections are checked for valid 503260684Skaiw * types, offsets and alignment. 504260684Skaiw * 505260684Skaiw * After a resync_elf() successfully returns, the ELF descriptor is 506260684Skaiw * ready for being handed over to _libelf_write_elf(). 507260684Skaiw */ 508260684Skaiw 509260684Skaiwstatic off_t 510260684Skaiw_libelf_resync_elf(Elf *e, struct _Elf_Extent_List *extents) 511260684Skaiw{ 512260684Skaiw int ec, eh_class; 513260684Skaiw unsigned int eh_byteorder, eh_version; 514260684Skaiw size_t align, fsz; 515260684Skaiw size_t phnum, shnum; 516260684Skaiw off_t rc, phoff, shoff; 517260684Skaiw void *ehdr, *phdr; 518260684Skaiw Elf32_Ehdr *eh32; 519260684Skaiw Elf64_Ehdr *eh64; 520260684Skaiw 521260684Skaiw rc = 0; 522260684Skaiw 523260684Skaiw ec = e->e_class; 524260684Skaiw 525260684Skaiw assert(ec == ELFCLASS32 || ec == ELFCLASS64); 526260684Skaiw 527260684Skaiw /* 528260684Skaiw * Prepare the EHDR. 529260684Skaiw */ 530260684Skaiw if ((ehdr = _libelf_ehdr(e, ec, 0)) == NULL) 531260684Skaiw return ((off_t) -1); 532260684Skaiw 533260684Skaiw eh32 = ehdr; 534260684Skaiw eh64 = ehdr; 535260684Skaiw 536260684Skaiw if (ec == ELFCLASS32) { 537260684Skaiw eh_byteorder = eh32->e_ident[EI_DATA]; 538260684Skaiw eh_class = eh32->e_ident[EI_CLASS]; 539276371Semaste phoff = (off_t) eh32->e_phoff; 540276371Semaste shoff = (off_t) eh32->e_shoff; 541260684Skaiw eh_version = eh32->e_version; 542260684Skaiw } else { 543260684Skaiw eh_byteorder = eh64->e_ident[EI_DATA]; 544260684Skaiw eh_class = eh64->e_ident[EI_CLASS]; 545276371Semaste phoff = (off_t) eh64->e_phoff; 546276371Semaste shoff = (off_t) eh64->e_shoff; 547260684Skaiw eh_version = eh64->e_version; 548260684Skaiw } 549260684Skaiw 550276371Semaste if (phoff < 0 || shoff < 0) { 551276371Semaste LIBELF_SET_ERROR(HEADER, 0); 552276371Semaste return ((off_t) -1); 553276371Semaste } 554276371Semaste 555260684Skaiw if (eh_version == EV_NONE) 556260684Skaiw eh_version = EV_CURRENT; 557260684Skaiw 558260684Skaiw if (eh_version != e->e_version) { /* always EV_CURRENT */ 559260684Skaiw LIBELF_SET_ERROR(VERSION, 0); 560260684Skaiw return ((off_t) -1); 561260684Skaiw } 562260684Skaiw 563260684Skaiw if (eh_class != e->e_class) { 564260684Skaiw LIBELF_SET_ERROR(CLASS, 0); 565260684Skaiw return ((off_t) -1); 566260684Skaiw } 567260684Skaiw 568260684Skaiw if (e->e_cmd != ELF_C_WRITE && eh_byteorder != e->e_byteorder) { 569260684Skaiw LIBELF_SET_ERROR(HEADER, 0); 570260684Skaiw return ((off_t) -1); 571260684Skaiw } 572260684Skaiw 573260684Skaiw shnum = e->e_u.e_elf.e_nscn; 574260684Skaiw phnum = e->e_u.e_elf.e_nphdr; 575260684Skaiw 576260684Skaiw e->e_byteorder = eh_byteorder; 577260684Skaiw 578260684Skaiw#define INITIALIZE_EHDR(E,EC,V) do { \ 579276371Semaste unsigned int _version = (unsigned int) (V); \ 580260684Skaiw (E)->e_ident[EI_MAG0] = ELFMAG0; \ 581260684Skaiw (E)->e_ident[EI_MAG1] = ELFMAG1; \ 582260684Skaiw (E)->e_ident[EI_MAG2] = ELFMAG2; \ 583260684Skaiw (E)->e_ident[EI_MAG3] = ELFMAG3; \ 584276371Semaste (E)->e_ident[EI_CLASS] = (unsigned char) (EC); \ 585276371Semaste (E)->e_ident[EI_VERSION] = (_version & 0xFFU); \ 586276371Semaste (E)->e_ehsize = (uint16_t) _libelf_fsize(ELF_T_EHDR, \ 587276371Semaste (EC), _version, (size_t) 1); \ 588276371Semaste (E)->e_phentsize = (uint16_t) ((phnum == 0) ? 0 : \ 589276371Semaste _libelf_fsize(ELF_T_PHDR, (EC), _version, \ 590276371Semaste (size_t) 1)); \ 591276371Semaste (E)->e_shentsize = (uint16_t) _libelf_fsize(ELF_T_SHDR, \ 592276371Semaste (EC), _version, (size_t) 1); \ 593260684Skaiw } while (0) 594260684Skaiw 595260684Skaiw if (ec == ELFCLASS32) 596260684Skaiw INITIALIZE_EHDR(eh32, ec, eh_version); 597260684Skaiw else 598260684Skaiw INITIALIZE_EHDR(eh64, ec, eh_version); 599260684Skaiw 600260684Skaiw (void) elf_flagehdr(e, ELF_C_SET, ELF_F_DIRTY); 601260684Skaiw 602276371Semaste rc += (off_t) _libelf_fsize(ELF_T_EHDR, ec, eh_version, (size_t) 1); 603260684Skaiw 604276371Semaste if (!_libelf_insert_extent(extents, ELF_EXTENT_EHDR, 0, (uint64_t) rc, 605276371Semaste ehdr)) 606260684Skaiw return ((off_t) -1); 607260684Skaiw 608260684Skaiw /* 609260684Skaiw * Compute the layout the program header table, if one is 610260684Skaiw * present. The program header table needs to be aligned to a 611260684Skaiw * `natural' boundary. 612260684Skaiw */ 613260684Skaiw if (phnum) { 614260684Skaiw fsz = _libelf_fsize(ELF_T_PHDR, ec, eh_version, phnum); 615260684Skaiw align = _libelf_falign(ELF_T_PHDR, ec); 616260684Skaiw 617260684Skaiw if (e->e_flags & ELF_F_LAYOUT) { 618260684Skaiw /* 619260684Skaiw * Check offsets for sanity. 620260684Skaiw */ 621260684Skaiw if (rc > phoff) { 622260684Skaiw LIBELF_SET_ERROR(LAYOUT, 0); 623260684Skaiw return ((off_t) -1); 624260684Skaiw } 625260684Skaiw 626276371Semaste if (phoff % (off_t) align) { 627260684Skaiw LIBELF_SET_ERROR(LAYOUT, 0); 628260684Skaiw return ((off_t) -1); 629260684Skaiw } 630260684Skaiw 631260684Skaiw } else 632276371Semaste phoff = roundup(rc, (off_t) align); 633260684Skaiw 634276371Semaste rc = phoff + (off_t) fsz; 635260684Skaiw 636260684Skaiw phdr = _libelf_getphdr(e, ec); 637260684Skaiw 638276371Semaste if (!_libelf_insert_extent(extents, ELF_EXTENT_PHDR, 639276371Semaste (uint64_t) phoff, fsz, phdr)) 640260684Skaiw return ((off_t) -1); 641260684Skaiw } else 642260684Skaiw phoff = 0; 643260684Skaiw 644260684Skaiw /* 645260684Skaiw * Compute the layout of the sections associated with the 646260684Skaiw * file. 647260684Skaiw */ 648260684Skaiw 649260684Skaiw if (e->e_cmd != ELF_C_WRITE && 650260684Skaiw (e->e_flags & LIBELF_F_SHDRS_LOADED) == 0 && 651260684Skaiw _libelf_load_section_headers(e, ehdr) == 0) 652260684Skaiw return ((off_t) -1); 653260684Skaiw 654260684Skaiw if ((rc = _libelf_resync_sections(e, rc, extents)) < 0) 655260684Skaiw return ((off_t) -1); 656260684Skaiw 657260684Skaiw /* 658260684Skaiw * Compute the space taken up by the section header table, if 659260684Skaiw * one is needed. 660260684Skaiw * 661260684Skaiw * If ELF_F_LAYOUT has been asserted, the application may have 662260684Skaiw * placed the section header table in between existing 663260684Skaiw * sections, so the net size of the file need not increase due 664260684Skaiw * to the presence of the section header table. 665260684Skaiw * 666260684Skaiw * If the library is responsible for laying out the object, 667260684Skaiw * the section header table is placed after section data. 668260684Skaiw */ 669260684Skaiw if (shnum) { 670260684Skaiw fsz = _libelf_fsize(ELF_T_SHDR, ec, eh_version, shnum); 671260684Skaiw align = _libelf_falign(ELF_T_SHDR, ec); 672260684Skaiw 673260684Skaiw if (e->e_flags & ELF_F_LAYOUT) { 674276371Semaste if (shoff % (off_t) align) { 675260684Skaiw LIBELF_SET_ERROR(LAYOUT, 0); 676260684Skaiw return ((off_t) -1); 677260684Skaiw } 678260684Skaiw } else 679276371Semaste shoff = roundup(rc, (off_t) align); 680260684Skaiw 681276371Semaste if (shoff + (off_t) fsz > rc) 682276371Semaste rc = shoff + (off_t) fsz; 683260684Skaiw 684276371Semaste if (!_libelf_insert_extent(extents, ELF_EXTENT_SHDR, 685276371Semaste (uint64_t) shoff, fsz, NULL)) 686260684Skaiw return ((off_t) -1); 687260684Skaiw } else 688260684Skaiw shoff = 0; 689260684Skaiw 690260684Skaiw /* 691260684Skaiw * Set the fields of the Executable Header that could potentially use 692260684Skaiw * extended numbering. 693260684Skaiw */ 694260684Skaiw _libelf_setphnum(e, ehdr, ec, phnum); 695260684Skaiw _libelf_setshnum(e, ehdr, ec, shnum); 696260684Skaiw 697260684Skaiw /* 698260684Skaiw * Update the `e_phoff' and `e_shoff' fields if the library is 699260684Skaiw * doing the layout. 700260684Skaiw */ 701260684Skaiw if ((e->e_flags & ELF_F_LAYOUT) == 0) { 702260684Skaiw if (ec == ELFCLASS32) { 703260684Skaiw eh32->e_phoff = (uint32_t) phoff; 704260684Skaiw eh32->e_shoff = (uint32_t) shoff; 705260684Skaiw } else { 706260684Skaiw eh64->e_phoff = (uint64_t) phoff; 707260684Skaiw eh64->e_shoff = (uint64_t) shoff; 708260684Skaiw } 709260684Skaiw } 710260684Skaiw 711260684Skaiw return (rc); 712260684Skaiw} 713260684Skaiw 714260684Skaiw/* 715260684Skaiw * Write out the contents of an ELF section. 716260684Skaiw */ 717260684Skaiw 718276371Semastestatic off_t 719276371Semaste_libelf_write_scn(Elf *e, unsigned char *nf, struct _Elf_Extent *ex) 720260684Skaiw{ 721276371Semaste off_t rc; 722367466Sdim int ec, em; 723260684Skaiw Elf_Scn *s; 724260684Skaiw int elftype; 725260684Skaiw Elf_Data *d, dst; 726260684Skaiw uint32_t sh_type; 727260684Skaiw struct _Libelf_Data *ld; 728260684Skaiw uint64_t sh_off, sh_size; 729276371Semaste size_t fsz, msz, nobjects; 730260684Skaiw 731260684Skaiw assert(ex->ex_type == ELF_EXTENT_SECTION); 732260684Skaiw 733260684Skaiw s = ex->ex_desc; 734276371Semaste rc = (off_t) ex->ex_start; 735260684Skaiw 736260684Skaiw if ((ec = e->e_class) == ELFCLASS32) { 737260684Skaiw sh_type = s->s_shdr.s_shdr32.sh_type; 738260684Skaiw sh_size = (uint64_t) s->s_shdr.s_shdr32.sh_size; 739260684Skaiw } else { 740260684Skaiw sh_type = s->s_shdr.s_shdr64.sh_type; 741260684Skaiw sh_size = s->s_shdr.s_shdr64.sh_size; 742260684Skaiw } 743260684Skaiw 744260684Skaiw /* 745260684Skaiw * Ignore sections that do not allocate space in the file. 746260684Skaiw */ 747260684Skaiw if (sh_type == SHT_NOBITS || sh_type == SHT_NULL || sh_size == 0) 748260684Skaiw return (rc); 749260684Skaiw 750260684Skaiw elftype = _libelf_xlate_shtype(sh_type); 751260684Skaiw assert(elftype >= ELF_T_FIRST && elftype <= ELF_T_LAST); 752260684Skaiw 753260684Skaiw sh_off = s->s_offset; 754260684Skaiw assert(sh_off % _libelf_falign(elftype, ec) == 0); 755260684Skaiw 756367466Sdim em = _libelf_elfmachine(e); 757367466Sdim#if 0 758367466Sdim assert(em >= EM_NONE && em < EM__LAST__); 759367466Sdim#endif 760367466Sdim 761260684Skaiw /* 762260684Skaiw * If the section has a `rawdata' descriptor, and the section 763260684Skaiw * contents have not been modified, use its contents directly. 764260684Skaiw * The `s_rawoff' member contains the offset into the original 765260684Skaiw * file, while `s_offset' contains its new location in the 766260684Skaiw * destination. 767260684Skaiw */ 768260684Skaiw 769260684Skaiw if (STAILQ_EMPTY(&s->s_data)) { 770260684Skaiw 771260684Skaiw if ((d = elf_rawdata(s, NULL)) == NULL) 772260684Skaiw return ((off_t) -1); 773260684Skaiw 774260684Skaiw STAILQ_FOREACH(ld, &s->s_rawdata, d_next) { 775260684Skaiw 776260684Skaiw d = &ld->d_data; 777260684Skaiw 778260684Skaiw if ((uint64_t) rc < sh_off + d->d_off) 779260684Skaiw (void) memset(nf + rc, 780276371Semaste LIBELF_PRIVATE(fillchar), 781276371Semaste (size_t) (sh_off + d->d_off - 782276371Semaste (uint64_t) rc)); 783276371Semaste rc = (off_t) (sh_off + d->d_off); 784260684Skaiw 785260684Skaiw assert(d->d_buf != NULL); 786260684Skaiw assert(d->d_type == ELF_T_BYTE); 787260684Skaiw assert(d->d_version == e->e_version); 788260684Skaiw 789260684Skaiw (void) memcpy(nf + rc, 790276371Semaste e->e_rawfile + s->s_rawoff + d->d_off, 791276371Semaste (size_t) d->d_size); 792260684Skaiw 793276371Semaste rc += (off_t) d->d_size; 794260684Skaiw } 795260684Skaiw 796260684Skaiw return (rc); 797260684Skaiw } 798260684Skaiw 799260684Skaiw /* 800260684Skaiw * Iterate over the set of data descriptors for this section. 801260684Skaiw * The prior call to _libelf_resync_elf() would have setup the 802260684Skaiw * descriptors for this step. 803260684Skaiw */ 804260684Skaiw 805260684Skaiw dst.d_version = e->e_version; 806260684Skaiw 807260684Skaiw STAILQ_FOREACH(ld, &s->s_data, d_next) { 808260684Skaiw 809260684Skaiw d = &ld->d_data; 810260684Skaiw 811367466Sdim if ((msz = _libelf_msize(d->d_type, ec, e->e_version)) == 0) 812367466Sdim return ((off_t) -1); 813260684Skaiw 814260684Skaiw if ((uint64_t) rc < sh_off + d->d_off) 815260684Skaiw (void) memset(nf + rc, 816276371Semaste LIBELF_PRIVATE(fillchar), 817276371Semaste (size_t) (sh_off + d->d_off - (uint64_t) rc)); 818260684Skaiw 819276371Semaste rc = (off_t) (sh_off + d->d_off); 820260684Skaiw 821260684Skaiw assert(d->d_buf != NULL); 822260684Skaiw assert(d->d_version == e->e_version); 823367466Sdim assert(d->d_size % msz == 0); 824317722Semaste assert(msz != 0); 825260684Skaiw 826276371Semaste nobjects = (size_t) (d->d_size / msz); 827260684Skaiw 828260684Skaiw fsz = _libelf_fsize(d->d_type, ec, e->e_version, nobjects); 829260684Skaiw 830260684Skaiw dst.d_buf = nf + rc; 831260684Skaiw dst.d_size = fsz; 832260684Skaiw 833367466Sdim if (_libelf_xlate(&dst, d, e->e_byteorder, ec, em, ELF_TOFILE) 834367466Sdim == NULL) 835260684Skaiw return ((off_t) -1); 836260684Skaiw 837276371Semaste rc += (off_t) fsz; 838260684Skaiw } 839260684Skaiw 840276371Semaste return (rc); 841260684Skaiw} 842260684Skaiw 843260684Skaiw/* 844260684Skaiw * Write out an ELF Executable Header. 845260684Skaiw */ 846260684Skaiw 847260684Skaiwstatic off_t 848276371Semaste_libelf_write_ehdr(Elf *e, unsigned char *nf, struct _Elf_Extent *ex) 849260684Skaiw{ 850367466Sdim int ec, em; 851260684Skaiw void *ehdr; 852260684Skaiw size_t fsz, msz; 853260684Skaiw Elf_Data dst, src; 854260684Skaiw 855260684Skaiw assert(ex->ex_type == ELF_EXTENT_EHDR); 856260684Skaiw assert(ex->ex_start == 0); /* Ehdr always comes first. */ 857260684Skaiw 858260684Skaiw ec = e->e_class; 859260684Skaiw 860260684Skaiw ehdr = _libelf_ehdr(e, ec, 0); 861260684Skaiw assert(ehdr != NULL); 862260684Skaiw 863260684Skaiw fsz = _libelf_fsize(ELF_T_EHDR, ec, e->e_version, (size_t) 1); 864367466Sdim if ((msz = _libelf_msize(ELF_T_EHDR, ec, e->e_version)) == 0) 865367466Sdim return ((off_t) -1); 866260684Skaiw 867367466Sdim em = _libelf_elfmachine(e); 868367466Sdim 869260684Skaiw (void) memset(&dst, 0, sizeof(dst)); 870260684Skaiw (void) memset(&src, 0, sizeof(src)); 871260684Skaiw 872260684Skaiw src.d_buf = ehdr; 873260684Skaiw src.d_size = msz; 874260684Skaiw src.d_type = ELF_T_EHDR; 875260684Skaiw src.d_version = dst.d_version = e->e_version; 876260684Skaiw 877260684Skaiw dst.d_buf = nf; 878260684Skaiw dst.d_size = fsz; 879260684Skaiw 880367466Sdim if (_libelf_xlate(&dst, &src, e->e_byteorder, ec, em, ELF_TOFILE) == 881260684Skaiw NULL) 882260684Skaiw return ((off_t) -1); 883260684Skaiw 884260684Skaiw return ((off_t) fsz); 885260684Skaiw} 886260684Skaiw 887260684Skaiw/* 888260684Skaiw * Write out an ELF program header table. 889260684Skaiw */ 890260684Skaiw 891260684Skaiwstatic off_t 892276371Semaste_libelf_write_phdr(Elf *e, unsigned char *nf, struct _Elf_Extent *ex) 893260684Skaiw{ 894367466Sdim int ec, em; 895260684Skaiw void *ehdr; 896260684Skaiw Elf32_Ehdr *eh32; 897260684Skaiw Elf64_Ehdr *eh64; 898260684Skaiw Elf_Data dst, src; 899367466Sdim size_t fsz, msz, phnum; 900260684Skaiw uint64_t phoff; 901260684Skaiw 902260684Skaiw assert(ex->ex_type == ELF_EXTENT_PHDR); 903260684Skaiw 904260684Skaiw ec = e->e_class; 905367466Sdim 906260684Skaiw ehdr = _libelf_ehdr(e, ec, 0); 907367466Sdim assert(ehdr != NULL); 908367466Sdim 909260684Skaiw phnum = e->e_u.e_elf.e_nphdr; 910260684Skaiw assert(phnum > 0); 911260684Skaiw 912260684Skaiw if (ec == ELFCLASS32) { 913260684Skaiw eh32 = (Elf32_Ehdr *) ehdr; 914260684Skaiw phoff = (uint64_t) eh32->e_phoff; 915260684Skaiw } else { 916260684Skaiw eh64 = (Elf64_Ehdr *) ehdr; 917260684Skaiw phoff = eh64->e_phoff; 918260684Skaiw } 919260684Skaiw 920367466Sdim em = _libelf_elfmachine(e); 921367466Sdim 922260684Skaiw assert(phoff > 0); 923260684Skaiw assert(ex->ex_start == phoff); 924260684Skaiw assert(phoff % _libelf_falign(ELF_T_PHDR, ec) == 0); 925260684Skaiw 926260684Skaiw (void) memset(&dst, 0, sizeof(dst)); 927260684Skaiw (void) memset(&src, 0, sizeof(src)); 928260684Skaiw 929367466Sdim if ((msz = _libelf_msize(ELF_T_PHDR, ec, e->e_version)) == 0) 930367466Sdim return ((off_t) -1); 931260684Skaiw fsz = _libelf_fsize(ELF_T_PHDR, ec, e->e_version, phnum); 932260684Skaiw assert(fsz > 0); 933260684Skaiw 934260684Skaiw src.d_buf = _libelf_getphdr(e, ec); 935260684Skaiw src.d_version = dst.d_version = e->e_version; 936260684Skaiw src.d_type = ELF_T_PHDR; 937367466Sdim src.d_size = phnum * msz; 938260684Skaiw 939260684Skaiw dst.d_size = fsz; 940260684Skaiw dst.d_buf = nf + ex->ex_start; 941260684Skaiw 942367466Sdim if (_libelf_xlate(&dst, &src, e->e_byteorder, ec, em, ELF_TOFILE) == 943260684Skaiw NULL) 944260684Skaiw return ((off_t) -1); 945260684Skaiw 946276371Semaste return ((off_t) (phoff + fsz)); 947260684Skaiw} 948260684Skaiw 949260684Skaiw/* 950260684Skaiw * Write out an ELF section header table. 951260684Skaiw */ 952260684Skaiw 953260684Skaiwstatic off_t 954276371Semaste_libelf_write_shdr(Elf *e, unsigned char *nf, struct _Elf_Extent *ex) 955260684Skaiw{ 956367466Sdim int ec, em; 957260684Skaiw void *ehdr; 958260684Skaiw Elf_Scn *scn; 959260684Skaiw uint64_t shoff; 960260684Skaiw Elf32_Ehdr *eh32; 961260684Skaiw Elf64_Ehdr *eh64; 962367466Sdim size_t fsz, msz, nscn; 963260684Skaiw Elf_Data dst, src; 964260684Skaiw 965260684Skaiw assert(ex->ex_type == ELF_EXTENT_SHDR); 966260684Skaiw 967260684Skaiw ec = e->e_class; 968367466Sdim 969260684Skaiw ehdr = _libelf_ehdr(e, ec, 0); 970367466Sdim assert(ehdr != NULL); 971367466Sdim 972260684Skaiw nscn = e->e_u.e_elf.e_nscn; 973260684Skaiw 974260684Skaiw if (ec == ELFCLASS32) { 975260684Skaiw eh32 = (Elf32_Ehdr *) ehdr; 976260684Skaiw shoff = (uint64_t) eh32->e_shoff; 977260684Skaiw } else { 978260684Skaiw eh64 = (Elf64_Ehdr *) ehdr; 979260684Skaiw shoff = eh64->e_shoff; 980260684Skaiw } 981260684Skaiw 982367466Sdim em = _libelf_elfmachine(e); 983367466Sdim 984260684Skaiw assert(nscn > 0); 985260684Skaiw assert(shoff % _libelf_falign(ELF_T_SHDR, ec) == 0); 986260684Skaiw assert(ex->ex_start == shoff); 987260684Skaiw 988260684Skaiw (void) memset(&dst, 0, sizeof(dst)); 989260684Skaiw (void) memset(&src, 0, sizeof(src)); 990260684Skaiw 991367466Sdim if ((msz = _libelf_msize(ELF_T_SHDR, ec, e->e_version)) == 0) 992367466Sdim return ((off_t) -1); 993367466Sdim 994260684Skaiw src.d_type = ELF_T_SHDR; 995367466Sdim src.d_size = msz; 996260684Skaiw src.d_version = dst.d_version = e->e_version; 997260684Skaiw 998260684Skaiw fsz = _libelf_fsize(ELF_T_SHDR, ec, e->e_version, (size_t) 1); 999260684Skaiw 1000367466Sdim RB_FOREACH(scn, scntree, &e->e_u.e_elf.e_scn) { 1001260684Skaiw if (ec == ELFCLASS32) 1002260684Skaiw src.d_buf = &scn->s_shdr.s_shdr32; 1003260684Skaiw else 1004260684Skaiw src.d_buf = &scn->s_shdr.s_shdr64; 1005260684Skaiw 1006260684Skaiw dst.d_size = fsz; 1007260684Skaiw dst.d_buf = nf + ex->ex_start + scn->s_ndx * fsz; 1008260684Skaiw 1009367466Sdim if (_libelf_xlate(&dst, &src, e->e_byteorder, ec, em, 1010367466Sdim ELF_TOFILE) == NULL) 1011260684Skaiw return ((off_t) -1); 1012260684Skaiw } 1013260684Skaiw 1014276371Semaste return ((off_t) (ex->ex_start + nscn * fsz)); 1015260684Skaiw} 1016260684Skaiw 1017260684Skaiw/* 1018260684Skaiw * Write out the file image. 1019260684Skaiw * 1020260684Skaiw * The original file could have been mapped in with an ELF_C_RDWR 1021260684Skaiw * command and the application could have added new content or 1022260684Skaiw * re-arranged its sections before calling elf_update(). Consequently 1023260684Skaiw * its not safe to work `in place' on the original file. So we 1024260684Skaiw * malloc() the required space for the updated ELF object and build 1025260684Skaiw * the object there and write it out to the underlying file at the 1026260684Skaiw * end. Note that the application may have opened the underlying file 1027260684Skaiw * in ELF_C_RDWR and only retrieved/modified a few sections. We take 1028260684Skaiw * care to avoid translating file sections unnecessarily. 1029260684Skaiw * 1030260684Skaiw * Gaps in the coverage of the file by the file's sections will be 1031260684Skaiw * filled with the fill character set by elf_fill(3). 1032260684Skaiw */ 1033260684Skaiw 1034260684Skaiwstatic off_t 1035260684Skaiw_libelf_write_elf(Elf *e, off_t newsize, struct _Elf_Extent_List *extents) 1036260684Skaiw{ 1037260684Skaiw off_t nrc, rc; 1038260684Skaiw Elf_Scn *scn, *tscn; 1039260684Skaiw struct _Elf_Extent *ex; 1040276371Semaste unsigned char *newfile; 1041260684Skaiw 1042260684Skaiw assert(e->e_kind == ELF_K_ELF); 1043260684Skaiw assert(e->e_cmd == ELF_C_RDWR || e->e_cmd == ELF_C_WRITE); 1044260684Skaiw assert(e->e_fd >= 0); 1045260684Skaiw 1046260684Skaiw if ((newfile = malloc((size_t) newsize)) == NULL) { 1047260684Skaiw LIBELF_SET_ERROR(RESOURCE, errno); 1048260684Skaiw return ((off_t) -1); 1049260684Skaiw } 1050260684Skaiw 1051260684Skaiw nrc = rc = 0; 1052260684Skaiw SLIST_FOREACH(ex, extents, ex_next) { 1053260684Skaiw 1054260684Skaiw /* Fill inter-extent gaps. */ 1055260684Skaiw if (ex->ex_start > (size_t) rc) 1056260684Skaiw (void) memset(newfile + rc, LIBELF_PRIVATE(fillchar), 1057276371Semaste (size_t) (ex->ex_start - (uint64_t) rc)); 1058260684Skaiw 1059260684Skaiw switch (ex->ex_type) { 1060260684Skaiw case ELF_EXTENT_EHDR: 1061260684Skaiw if ((nrc = _libelf_write_ehdr(e, newfile, ex)) < 0) 1062260684Skaiw goto error; 1063260684Skaiw break; 1064260684Skaiw 1065260684Skaiw case ELF_EXTENT_PHDR: 1066260684Skaiw if ((nrc = _libelf_write_phdr(e, newfile, ex)) < 0) 1067260684Skaiw goto error; 1068260684Skaiw break; 1069260684Skaiw 1070260684Skaiw case ELF_EXTENT_SECTION: 1071260684Skaiw if ((nrc = _libelf_write_scn(e, newfile, ex)) < 0) 1072260684Skaiw goto error; 1073260684Skaiw break; 1074260684Skaiw 1075260684Skaiw case ELF_EXTENT_SHDR: 1076260684Skaiw if ((nrc = _libelf_write_shdr(e, newfile, ex)) < 0) 1077260684Skaiw goto error; 1078260684Skaiw break; 1079260684Skaiw 1080260684Skaiw default: 1081260684Skaiw assert(0); 1082260684Skaiw break; 1083260684Skaiw } 1084260684Skaiw 1085260684Skaiw assert(ex->ex_start + ex->ex_size == (size_t) nrc); 1086260684Skaiw assert(rc < nrc); 1087260684Skaiw 1088260684Skaiw rc = nrc; 1089260684Skaiw } 1090260684Skaiw 1091260684Skaiw assert(rc == newsize); 1092260684Skaiw 1093260684Skaiw /* 1094260684Skaiw * For regular files, throw away existing file content and 1095260684Skaiw * unmap any existing mappings. 1096260684Skaiw */ 1097260684Skaiw if ((e->e_flags & LIBELF_F_SPECIAL_FILE) == 0) { 1098260684Skaiw if (ftruncate(e->e_fd, (off_t) 0) < 0 || 1099260684Skaiw lseek(e->e_fd, (off_t) 0, SEEK_SET)) { 1100260684Skaiw LIBELF_SET_ERROR(IO, errno); 1101260684Skaiw goto error; 1102260684Skaiw } 1103260684Skaiw#if ELFTC_HAVE_MMAP 1104260684Skaiw if (e->e_flags & LIBELF_F_RAWFILE_MMAP) { 1105260684Skaiw assert(e->e_rawfile != NULL); 1106260684Skaiw assert(e->e_cmd == ELF_C_RDWR); 1107367466Sdim if (munmap(e->e_rawfile, (size_t) e->e_rawsize) < 0) { 1108260684Skaiw LIBELF_SET_ERROR(IO, errno); 1109260684Skaiw goto error; 1110260684Skaiw } 1111260684Skaiw } 1112260684Skaiw#endif 1113260684Skaiw } 1114260684Skaiw 1115260684Skaiw /* 1116260684Skaiw * Write out the new contents. 1117260684Skaiw */ 1118260684Skaiw if (write(e->e_fd, newfile, (size_t) newsize) != newsize) { 1119260684Skaiw LIBELF_SET_ERROR(IO, errno); 1120260684Skaiw goto error; 1121260684Skaiw } 1122260684Skaiw 1123260684Skaiw /* 1124260684Skaiw * For files opened in ELF_C_RDWR mode, set up the new 'raw' 1125260684Skaiw * contents. 1126260684Skaiw */ 1127260684Skaiw if (e->e_cmd == ELF_C_RDWR) { 1128260684Skaiw assert(e->e_rawfile != NULL); 1129260684Skaiw assert((e->e_flags & LIBELF_F_RAWFILE_MALLOC) || 1130260684Skaiw (e->e_flags & LIBELF_F_RAWFILE_MMAP)); 1131260684Skaiw if (e->e_flags & LIBELF_F_RAWFILE_MALLOC) { 1132367466Sdim assert((e->e_flags & LIBELF_F_RAWFILE_MMAP) == 0); 1133260684Skaiw free(e->e_rawfile); 1134260684Skaiw e->e_rawfile = newfile; 1135260684Skaiw newfile = NULL; 1136260684Skaiw } 1137260684Skaiw#if ELFTC_HAVE_MMAP 1138260684Skaiw else if (e->e_flags & LIBELF_F_RAWFILE_MMAP) { 1139367466Sdim assert((e->e_flags & LIBELF_F_RAWFILE_MALLOC) == 0); 1140260684Skaiw if ((e->e_rawfile = mmap(NULL, (size_t) newsize, 1141260684Skaiw PROT_READ, MAP_PRIVATE, e->e_fd, (off_t) 0)) == 1142260684Skaiw MAP_FAILED) { 1143260684Skaiw LIBELF_SET_ERROR(IO, errno); 1144260684Skaiw goto error; 1145260684Skaiw } 1146260684Skaiw } 1147260684Skaiw#endif /* ELFTC_HAVE_MMAP */ 1148260684Skaiw 1149260684Skaiw /* Record the new size of the file. */ 1150367466Sdim e->e_rawsize = newsize; 1151260684Skaiw } else { 1152260684Skaiw /* File opened in ELF_C_WRITE mode. */ 1153260684Skaiw assert(e->e_rawfile == NULL); 1154260684Skaiw } 1155260684Skaiw 1156260684Skaiw /* 1157260684Skaiw * Reset flags, remove existing section descriptors and 1158260684Skaiw * {E,P}HDR pointers so that a subsequent elf_get{e,p}hdr() 1159260684Skaiw * and elf_getscn() will function correctly. 1160260684Skaiw */ 1161260684Skaiw 1162260684Skaiw e->e_flags &= ~ELF_F_DIRTY; 1163260684Skaiw 1164367466Sdim RB_FOREACH_SAFE(scn, scntree, &e->e_u.e_elf.e_scn, tscn) 1165260684Skaiw _libelf_release_scn(scn); 1166260684Skaiw 1167260684Skaiw if (e->e_class == ELFCLASS32) { 1168260684Skaiw free(e->e_u.e_elf.e_ehdr.e_ehdr32); 1169260684Skaiw if (e->e_u.e_elf.e_phdr.e_phdr32) 1170260684Skaiw free(e->e_u.e_elf.e_phdr.e_phdr32); 1171260684Skaiw 1172260684Skaiw e->e_u.e_elf.e_ehdr.e_ehdr32 = NULL; 1173260684Skaiw e->e_u.e_elf.e_phdr.e_phdr32 = NULL; 1174260684Skaiw } else { 1175260684Skaiw free(e->e_u.e_elf.e_ehdr.e_ehdr64); 1176260684Skaiw if (e->e_u.e_elf.e_phdr.e_phdr64) 1177260684Skaiw free(e->e_u.e_elf.e_phdr.e_phdr64); 1178260684Skaiw 1179260684Skaiw e->e_u.e_elf.e_ehdr.e_ehdr64 = NULL; 1180260684Skaiw e->e_u.e_elf.e_phdr.e_phdr64 = NULL; 1181260684Skaiw } 1182260684Skaiw 1183260684Skaiw /* Free the temporary buffer. */ 1184260684Skaiw if (newfile) 1185260684Skaiw free(newfile); 1186260684Skaiw 1187260684Skaiw return (rc); 1188260684Skaiw 1189260684Skaiw error: 1190260684Skaiw free(newfile); 1191260684Skaiw 1192260684Skaiw return ((off_t) -1); 1193260684Skaiw} 1194260684Skaiw 1195260684Skaiw/* 1196260684Skaiw * Update an ELF object. 1197260684Skaiw */ 1198260684Skaiw 1199260684Skaiwoff_t 1200260684Skaiwelf_update(Elf *e, Elf_Cmd c) 1201260684Skaiw{ 1202260684Skaiw int ec; 1203260684Skaiw off_t rc; 1204260684Skaiw struct _Elf_Extent_List extents; 1205260684Skaiw 1206260684Skaiw rc = (off_t) -1; 1207260684Skaiw 1208260684Skaiw if (e == NULL || e->e_kind != ELF_K_ELF || 1209260684Skaiw (c != ELF_C_NULL && c != ELF_C_WRITE)) { 1210260684Skaiw LIBELF_SET_ERROR(ARGUMENT, 0); 1211260684Skaiw return (rc); 1212260684Skaiw } 1213260684Skaiw 1214260684Skaiw if ((ec = e->e_class) != ELFCLASS32 && ec != ELFCLASS64) { 1215260684Skaiw LIBELF_SET_ERROR(CLASS, 0); 1216260684Skaiw return (rc); 1217260684Skaiw } 1218260684Skaiw 1219260684Skaiw if (e->e_version == EV_NONE) 1220260684Skaiw e->e_version = EV_CURRENT; 1221260684Skaiw 1222260684Skaiw if (c == ELF_C_WRITE && e->e_cmd == ELF_C_READ) { 1223260684Skaiw LIBELF_SET_ERROR(MODE, 0); 1224260684Skaiw return (rc); 1225260684Skaiw } 1226260684Skaiw 1227260684Skaiw SLIST_INIT(&extents); 1228260684Skaiw 1229260684Skaiw if ((rc = _libelf_resync_elf(e, &extents)) < 0) 1230260684Skaiw goto done; 1231260684Skaiw 1232260684Skaiw if (c == ELF_C_NULL) 1233260684Skaiw goto done; 1234260684Skaiw 1235260684Skaiw if (e->e_fd < 0) { 1236260684Skaiw rc = (off_t) -1; 1237260684Skaiw LIBELF_SET_ERROR(SEQUENCE, 0); 1238260684Skaiw goto done; 1239260684Skaiw } 1240260684Skaiw 1241260684Skaiw rc = _libelf_write_elf(e, rc, &extents); 1242260684Skaiw 1243260684Skaiwdone: 1244260684Skaiw _libelf_release_extents(&extents); 1245338411Semaste e->e_flags &= ~LIBELF_F_SHDRS_LOADED; 1246260684Skaiw return (rc); 1247260684Skaiw} 1248