diff options
Diffstat (limited to 'ext/libelf/elf_update.c')
| -rw-r--r-- | ext/libelf/elf_update.c | 885 |
1 files changed, 885 insertions, 0 deletions
diff --git a/ext/libelf/elf_update.c b/ext/libelf/elf_update.c new file mode 100644 index 000000000..6959d3c3e --- /dev/null +++ b/ext/libelf/elf_update.c @@ -0,0 +1,885 @@ +/*- + * Copyright (c) 2006 Joseph Koshy + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + */ + + +#include <sys/mman.h> +#include <sys/param.h> +#ifdef __sun +#include <sys/sysmacros.h> +#endif + +#include <assert.h> +#include <errno.h> +#include "gelf.h" +#include "libelf.h" +#include <stdlib.h> +#include <string.h> +#include <unistd.h> + +#include "_libelf.h" + +/* + * Update the internal data structures associated with an ELF object. + * Returns the size in bytes the ELF object would occupy in its file + * representation. + * + * After a successful call to this function, the following structures + * are updated: + * + * - The ELF header is updated. + * - All sections are sorted in order of ascending addresses and their + * section header table entries updated. An error is signalled + * if an overlap was detected among sections. + * - All data descriptors associated with a section are sorted in order + * of ascending addresses. Overlaps, if detected, are signalled as + * errors. Other sanity checks for alignments, section types etc. are + * made. + * + * After a resync_elf() successfully returns, the ELF descriptor is + * ready for being handed over to _libelf_write_elf(). + * + * File alignments: + * PHDR - Addr + * SHDR - Addr + * + * XXX: how do we handle 'flags'. + */ + +/* + * Compute the extents of a section, by looking at the. + */ +static int +_libelf_compute_section_extents(Elf *e, Elf_Scn *s, off_t *rc) +{ + int ec; + Elf_Data *d, *td; + unsigned int elftype; + uint32_t sh_type; + uint64_t d_align; + uint64_t sh_align, sh_entsize, sh_offset, sh_size; + uint64_t scn_size, scn_alignment; + + /* + * We need to recompute library private data structures if one + * or more of the following is true: + * - The underlying Shdr structure has been marked `dirty'. Significant + * fields include: `sh_offset', `sh_type', `sh_size', `sh_addralign'. + * - The Elf_Data structures part of this section have been marked + * `dirty'. Affected members include `d_align', `d_offset', `d_type', + * and `d_size'. + * - The section as a whole is `dirty', e.g., it has been allocated + * using elf_newscn(), or if a new Elf_Data structure was added using + * elf_newdata(). + * + * Each of these conditions would result in the ELF_F_DIRTY bit being + * set on the section descriptor's `s_flags' field. + */ + + ec = e->e_class; + + if (ec == ELFCLASS32) { + sh_type = s->s_shdr.s_shdr32.sh_type; + sh_align = (uint64_t) s->s_shdr.s_shdr32.sh_addralign; + sh_entsize = (uint64_t) s->s_shdr.s_shdr32.sh_entsize; + sh_offset = (uint64_t) s->s_shdr.s_shdr32.sh_offset; + sh_size = (uint64_t) s->s_shdr.s_shdr32.sh_size; + } else { + sh_type = s->s_shdr.s_shdr64.sh_type; + sh_align = s->s_shdr.s_shdr64.sh_addralign; + sh_entsize = s->s_shdr.s_shdr64.sh_entsize; + sh_offset = s->s_shdr.s_shdr64.sh_offset; + sh_size = s->s_shdr.s_shdr64.sh_size; + } + + if (sh_type == SHT_NULL || sh_type == SHT_NOBITS) + return (1); + + if ((s->s_flags & ELF_F_DIRTY) == 0) { + if ((size_t) *rc < sh_offset + sh_size) + *rc = sh_offset + sh_size; + return (1); + } + + elftype = _libelf_xlate_shtype(sh_type); + if (elftype > ELF_T_LAST) { + LIBELF_SET_ERROR(SECTION, 0); + return (0); + } + + /* + * Compute the extent of the data descriptors associated with + * this section. + */ + scn_alignment = 0; + if (sh_align == 0) + sh_align = _libelf_falign(elftype, ec); + + /* Compute the section alignment. */ + STAILQ_FOREACH(d, &s->s_data, d_next) { + if (d->d_type != elftype) { + LIBELF_SET_ERROR(DATA, 0); + return (0); + } + if (d->d_version != e->e_version) { + LIBELF_SET_ERROR(VERSION, 0); + return (0); + } + if ((d_align = d->d_align) % sh_align) { + LIBELF_SET_ERROR(LAYOUT, 0); + return (0); + } + if (d_align == 0 || (d_align & (d_align - 1))) { + LIBELF_SET_ERROR(DATA, 0); + return (0); + } + if (d_align > scn_alignment) + scn_alignment = d_align; + } + + scn_size = 0L; + + STAILQ_FOREACH_SAFE(d, &s->s_data, d_next, td) { + if (e->e_flags & ELF_F_LAYOUT) { + if ((uint64_t) d->d_off + d->d_size > scn_size) + scn_size = d->d_off + d->d_size; + } else { + scn_size = roundup(scn_size, scn_alignment); + d->d_off = scn_size; + scn_size += d->d_size; + } + } + + /* + * If the application is requesting full control over the layout + * of the section, check its values for sanity. + */ + if (e->e_flags & ELF_F_LAYOUT) { + if (scn_alignment > sh_align || sh_offset % sh_align || + sh_size < scn_size) { + LIBELF_SET_ERROR(LAYOUT, 0); + return (0); + } + } else { + /* + * Otherwise compute the values in the section header. + */ + + if (scn_alignment > sh_align) + sh_align = scn_alignment; + + /* + * If the section entry size is zero, try and fill in an + * appropriate entry size. Per the elf(5) manual page + * sections without fixed-size entries should have their + * 'sh_entsize' field set to zero. + */ + if (sh_entsize == 0 && + (sh_entsize = _libelf_fsize(elftype, ec, e->e_version, + (size_t) 1)) == 1) + sh_entsize = 0; + + sh_size = scn_size; + sh_offset = roundup(*rc, sh_align); + + if (ec == ELFCLASS32) { + s->s_shdr.s_shdr32.sh_addralign = (uint32_t) sh_align; + s->s_shdr.s_shdr32.sh_entsize = (uint32_t) sh_entsize; + s->s_shdr.s_shdr32.sh_offset = (uint32_t) sh_offset; + s->s_shdr.s_shdr32.sh_size = (uint32_t) sh_size; + } else { + s->s_shdr.s_shdr64.sh_addralign = sh_align; + s->s_shdr.s_shdr64.sh_entsize = sh_entsize; + s->s_shdr.s_shdr64.sh_offset = sh_offset; + s->s_shdr.s_shdr64.sh_size = sh_size; + } + } + + if ((size_t) *rc < sh_offset + sh_size) + *rc = sh_offset + sh_size; + + s->s_size = sh_size; + s->s_offset = sh_offset; + return (1); +} + + +/* + * Insert a section in ascending order in the list + */ + +static int +_libelf_insert_section(Elf *e, Elf_Scn *s) +{ + Elf_Scn *t, *prevt; + uint64_t smax, smin, tmax, tmin; + + smin = s->s_offset; + smax = smin + s->s_size; + + prevt = NULL; + STAILQ_FOREACH(t, &e->e_u.e_elf.e_scn, s_next) { + tmin = t->s_offset; + tmax = tmin + t->s_size; + + /* check if there is an overlap */ + if (tmax < smin) { + prevt = t; + continue; + } else if (smax < tmin) + break; + else { + LIBELF_SET_ERROR(LAYOUT, 0); + return (0); + } + } + + if (prevt) + STAILQ_INSERT_AFTER(&e->e_u.e_elf.e_scn, prevt, s, s_next); + else + STAILQ_INSERT_HEAD(&e->e_u.e_elf.e_scn, s, s_next); + return (1); +} + +static off_t +_libelf_resync_sections(Elf *e, off_t rc) +{ + int ec; + off_t nrc; + size_t sh_type; + Elf_Scn *s, *ts; + + ec = e->e_class; + + /* + * Make a pass through sections, computing the extent of each + * section. Order in increasing order of addresses. + */ + + nrc = rc; + STAILQ_FOREACH(s, &e->e_u.e_elf.e_scn, s_next) + if (_libelf_compute_section_extents(e, s, &nrc) == 0) + return ((off_t) -1); + + STAILQ_FOREACH_SAFE(s, &e->e_u.e_elf.e_scn, s_next, ts) { + if (ec == ELFCLASS32) + sh_type = s->s_shdr.s_shdr32.sh_type; + else + sh_type = s->s_shdr.s_shdr64.sh_type; + + /* XXX Do we need the 'size' field of an SHT_NOBITS section */ + if (sh_type == SHT_NOBITS || sh_type == SHT_NULL) + continue; + + if (s->s_offset < (uint64_t) rc) { + if (s->s_offset + s->s_size < (uint64_t) rc) { + /* + * Try insert this section in the + * correct place in the list, + * detecting overlaps if any. + */ + STAILQ_REMOVE(&e->e_u.e_elf.e_scn, s, _Elf_Scn, + s_next); + if (_libelf_insert_section(e, s) == 0) + return ((off_t) -1); + } else { + LIBELF_SET_ERROR(LAYOUT, 0); + return ((off_t) -1); + } + } else + rc = s->s_offset + s->s_size; + } + + assert(nrc == rc); + + return (rc); +} + +static off_t +_libelf_resync_elf(Elf *e) +{ + int ec, eh_class, eh_type; + unsigned int eh_byteorder, eh_version; + size_t align, fsz; + size_t phnum, shnum; + off_t rc, phoff, shoff; + void *ehdr; + Elf32_Ehdr *eh32; + Elf64_Ehdr *eh64; + + rc = 0; + + ec = e->e_class; + + assert(ec == ELFCLASS32 || ec == ELFCLASS64); + + /* + * Prepare the EHDR. + */ + if ((ehdr = _libelf_ehdr(e, ec, 0)) == NULL) + return ((off_t) -1); + + eh32 = ehdr; + eh64 = ehdr; + + if (ec == ELFCLASS32) { + eh_byteorder = eh32->e_ident[EI_DATA]; + eh_class = eh32->e_ident[EI_CLASS]; + phoff = (uint64_t) eh32->e_phoff; + shoff = (uint64_t) eh32->e_shoff; + eh_type = eh32->e_type; + eh_version = eh32->e_version; + } else { + eh_byteorder = eh64->e_ident[EI_DATA]; + eh_class = eh64->e_ident[EI_CLASS]; + phoff = eh64->e_phoff; + shoff = eh64->e_shoff; + eh_type = eh64->e_type; + eh_version = eh64->e_version; + } + + if (eh_version == EV_NONE) + eh_version = EV_CURRENT; + + if (eh_version != e->e_version) { /* always EV_CURRENT */ + LIBELF_SET_ERROR(VERSION, 0); + return ((off_t) -1); + } + + if (eh_class != e->e_class) { + LIBELF_SET_ERROR(CLASS, 0); + return ((off_t) -1); + } + + if (e->e_cmd != ELF_C_WRITE && eh_byteorder != e->e_byteorder) { + LIBELF_SET_ERROR(HEADER, 0); + return ((off_t) -1); + } + + shnum = e->e_u.e_elf.e_nscn; + phnum = e->e_u.e_elf.e_nphdr; + + e->e_byteorder = eh_byteorder; + +#define INITIALIZE_EHDR(E,EC,V) do { \ + (E)->e_ident[EI_MAG0] = ELFMAG0; \ + (E)->e_ident[EI_MAG1] = ELFMAG1; \ + (E)->e_ident[EI_MAG2] = ELFMAG2; \ + (E)->e_ident[EI_MAG3] = ELFMAG3; \ + (E)->e_ident[EI_CLASS] = (EC); \ + (E)->e_ident[EI_VERSION] = (V); \ + (E)->e_ehsize = _libelf_fsize(ELF_T_EHDR, (EC), (V), \ + (size_t) 1); \ + (E)->e_phentsize = _libelf_fsize(ELF_T_PHDR, (EC), (V), \ + (size_t) 1); \ + (E)->e_shentsize = _libelf_fsize(ELF_T_SHDR, (EC), (V), \ + (size_t) 1); \ + } while (0) + + if (ec == ELFCLASS32) + INITIALIZE_EHDR(eh32, ec, eh_version); + else + INITIALIZE_EHDR(eh64, ec, eh_version); + + (void) elf_flagehdr(e, ELF_C_SET, ELF_F_DIRTY); + + rc += _libelf_fsize(ELF_T_EHDR, ec, eh_version, (size_t) 1); + + /* + * Compute the layout the program header table, if one is + * present. The program header table needs to be aligned to a + * `natural' boundary. + */ + if (phnum) { + fsz = _libelf_fsize(ELF_T_PHDR, ec, eh_version, phnum); + align = _libelf_falign(ELF_T_PHDR, ec); + + if (e->e_flags & ELF_F_LAYOUT) { + /* + * Check offsets for sanity. + */ + if (rc > phoff) { + LIBELF_SET_ERROR(HEADER, 0); + return ((off_t) -1); + } + + if (phoff % align) { + LIBELF_SET_ERROR(LAYOUT, 0); + return ((off_t) -1); + } + + } else + phoff = roundup(rc, align); + + rc = phoff + fsz; + } else + phoff = 0; + + /* + * Compute the layout of the sections associated with the + * file. + */ + + if ((rc = _libelf_resync_sections(e, rc)) < 0) + return ((off_t) -1); + + /* + * Compute the space taken up by the section header table, if + * one is needed. + */ + if (shnum) { + fsz = _libelf_fsize(ELF_T_SHDR, ec, eh_version, (size_t) 1); + align = _libelf_falign(ELF_T_SHDR, ec); + + if (e->e_flags & ELF_F_LAYOUT) { + if (rc > shoff) { + LIBELF_SET_ERROR(HEADER, 0); + return ((off_t) -1); + } + + if (shoff % align) { + LIBELF_SET_ERROR(LAYOUT, 0); + return ((off_t) -1); + } + } else + shoff = roundup(rc, align); + + rc = shoff + fsz * shnum; + } else + shoff = 0; + + /* + * Set the fields of the Executable Header that could potentially use + * extended numbering. + */ + _libelf_setphnum(e, ehdr, ec, phnum); + _libelf_setshnum(e, ehdr, ec, shnum); + + /* + * Update the `e_phoff' and `e_shoff' fields if the library is + * doing the layout. + */ + if ((e->e_flags & ELF_F_LAYOUT) == 0) { + if (ec == ELFCLASS32) { + eh32->e_phoff = (uint32_t) phoff; + eh32->e_shoff = (uint32_t) shoff; + } else { + eh64->e_phoff = (uint64_t) phoff; + eh64->e_shoff = (uint64_t) shoff; + } + } + + return (rc); +} + +/* + * Write out the contents of a section. + */ + +static off_t +_libelf_write_scn(Elf *e, char *nf, Elf_Scn *s, off_t rc) +{ + int ec; + size_t fsz, msz, nobjects; + uint32_t sh_type; + uint64_t sh_off; + int elftype; + Elf_Data *d, dst; + + if ((ec = e->e_class) == ELFCLASS32) + sh_type = s->s_shdr.s_shdr32.sh_type; + else + sh_type = s->s_shdr.s_shdr64.sh_type; + + /* + * Ignore sections that do not allocate space in the file. + */ + if (sh_type == SHT_NOBITS || sh_type == SHT_NULL) + return (rc); + + + elftype = _libelf_xlate_shtype(sh_type); + assert(elftype >= ELF_T_FIRST && elftype <= ELF_T_LAST); + + msz = _libelf_msize(elftype, ec, e->e_version); + + sh_off = s->s_offset; + assert(sh_off % _libelf_falign(elftype, ec) == 0); + + /* + * If the section has a `rawdata' descriptor, and the section + * contents have not been modified, use its contents directly. + * The `s_rawoff' member contains the offset into the original + * file, while `s_offset' contains its new location in the + * destination. + */ + + if (STAILQ_EMPTY(&s->s_data)) { + + if ((d = elf_rawdata(s, NULL)) == NULL) + return ((off_t) -1); + + STAILQ_FOREACH(d, &s->s_rawdata, d_next) { + if ((uint64_t) rc < sh_off + d->d_off) + (void) memset(nf + rc, + LIBELF_PRIVATE(fillchar), sh_off + + d->d_off - rc); + rc = sh_off + d->d_off; + + assert(d->d_buf != NULL); + assert(d->d_type == ELF_T_BYTE); + assert(d->d_version == e->e_version); + + (void) memcpy(nf + rc, + e->e_rawfile + s->s_rawoff + d->d_off, d->d_size); + + rc += d->d_size; + } + + return (rc); + } + + /* + * Iterate over the set of data descriptors for this section. + * The prior call to _libelf_resync_elf() would have setup the + * descriptors for this step. + */ + + dst.d_version = e->e_version; + + STAILQ_FOREACH(d, &s->s_data, d_next) { + + if ((uint64_t) rc < sh_off + d->d_off) + (void) memset(nf + rc, + LIBELF_PRIVATE(fillchar), sh_off + d->d_off - rc); + + rc = sh_off + d->d_off; + + assert(d->d_buf != NULL); + assert(d->d_type == (Elf_Type) elftype); + assert(d->d_version == e->e_version); + assert(d->d_size % msz == 0); + + nobjects = d->d_size / msz; + + fsz = _libelf_fsize(elftype, ec, e->e_version, nobjects); + + dst.d_buf = nf + rc; + dst.d_size = fsz; + + if (_libelf_xlate(&dst, d, e->e_byteorder, ec, ELF_TOFILE) == + NULL) + return ((off_t) -1); + + rc += fsz; + } + + return ((off_t) rc); +} + +/* + * Write out the file image. + * + * The original file could have been mapped in with an ELF_C_RDWR + * command and the application could have added new content or + * re-arranged its sections before calling elf_update(). Consequently + * its not safe to work `in place' on the original file. So we + * malloc() the required space for the updated ELF object and build + * the object there and write it out to the underlying file at the + * end. Note that the application may have opened the underlying file + * in ELF_C_RDWR and only retrieved/modified a few sections. We take + * care to avoid translating file sections unnecessarily. + * + * Gaps in the coverage of the file by the file's sections will be + * filled with the fill character set by elf_fill(3). + */ + +static off_t +_libelf_write_elf(Elf *e, off_t newsize) +{ + int ec; + off_t rc; + size_t fsz, msz, phnum, shnum; + uint64_t phoff, shoff; + void *ehdr; + char *newfile; + Elf_Data dst, src; + Elf_Scn *scn, *tscn; + Elf32_Ehdr *eh32; + Elf64_Ehdr *eh64; + + assert(e->e_kind == ELF_K_ELF); + assert(e->e_cmd != ELF_C_READ); + assert(e->e_fd >= 0); + + if ((newfile = malloc((size_t) newsize)) == NULL) { + LIBELF_SET_ERROR(RESOURCE, errno); + return ((off_t) -1); + } + + ec = e->e_class; + + ehdr = _libelf_ehdr(e, ec, 0); + assert(ehdr != NULL); + + phnum = e->e_u.e_elf.e_nphdr; + + if (ec == ELFCLASS32) { + eh32 = (Elf32_Ehdr *) ehdr; + + phoff = (uint64_t) eh32->e_phoff; + shnum = eh32->e_shnum; + shoff = (uint64_t) eh32->e_shoff; + } else { + eh64 = (Elf64_Ehdr *) ehdr; + + phoff = eh64->e_phoff; + shnum = eh64->e_shnum; + shoff = eh64->e_shoff; + } + + fsz = _libelf_fsize(ELF_T_EHDR, ec, e->e_version, (size_t) 1); + msz = _libelf_msize(ELF_T_EHDR, ec, e->e_version); + + (void) memset(&dst, 0, sizeof(dst)); + (void) memset(&src, 0, sizeof(src)); + + src.d_buf = ehdr; + src.d_size = msz; + src.d_type = ELF_T_EHDR; + src.d_version = dst.d_version = e->e_version; + + rc = 0; + + dst.d_buf = newfile + rc; + dst.d_size = fsz; + + if (_libelf_xlate(&dst, &src, e->e_byteorder, ec, ELF_TOFILE) == + NULL) + goto error; + + rc += fsz; + + /* + * Write the program header table if present. + */ + + if (phnum != 0 && phoff != 0) { + assert((unsigned) rc <= phoff); + + fsz = _libelf_fsize(ELF_T_PHDR, ec, e->e_version, phnum); + + assert(phoff % _libelf_falign(ELF_T_PHDR, ec) == 0); + assert(fsz > 0); + + src.d_version = dst.d_version = e->e_version; + src.d_type = ELF_T_PHDR; + + if (ec == ELFCLASS32) + src.d_buf = e->e_u.e_elf.e_phdr.e_phdr32; + else + src.d_buf = e->e_u.e_elf.e_phdr.e_phdr64; + + src.d_size = phnum * _libelf_msize(ELF_T_PHDR, ec, + e->e_version); + + dst.d_size = fsz; + + if ((uint64_t) rc < phoff) + (void) memset(newfile + rc, + LIBELF_PRIVATE(fillchar), phoff - rc); + + dst.d_buf = newfile + rc; + + if (_libelf_xlate(&dst, &src, e->e_byteorder, ec, ELF_TOFILE) == + NULL) + goto error; + + rc = phoff + fsz; + } + + /* + * Write out individual sections. + */ + + STAILQ_FOREACH(scn, &e->e_u.e_elf.e_scn, s_next) + if ((rc = _libelf_write_scn(e, newfile, scn, rc)) < 0) + goto error; + + /* + * Write out the section header table, if required. + */ + + if (shnum != 0 && shoff != 0) { + assert((unsigned) rc <= shoff); + + if ((uint64_t) rc < shoff) + (void) memset(newfile + rc, + LIBELF_PRIVATE(fillchar), shoff - rc); + + rc = shoff; + + assert(rc % _libelf_falign(ELF_T_SHDR, ec) == 0); + + src.d_type = ELF_T_SHDR; + src.d_size = _libelf_msize(ELF_T_SHDR, ec, e->e_version); + src.d_version = dst.d_version = e->e_version; + + fsz = _libelf_fsize(ELF_T_SHDR, ec, e->e_version, (size_t) 1); + + STAILQ_FOREACH(scn, &e->e_u.e_elf.e_scn, s_next) { + if (ec == ELFCLASS32) + src.d_buf = &scn->s_shdr.s_shdr32; + else + src.d_buf = &scn->s_shdr.s_shdr64; + + dst.d_size = fsz; + dst.d_buf = newfile + rc; + + if (_libelf_xlate(&dst, &src, e->e_byteorder, ec, + ELF_TOFILE) != &dst) + goto error; + + rc += fsz; + } + } + + /* + */ + + assert(rc == newsize); + + /* + * Write out the constructed contents and remap the file in + * read-only. + */ + + if (e->e_rawfile && munmap(e->e_rawfile, e->e_rawsize) < 0) { + LIBELF_SET_ERROR(IO, errno); + goto error; + } + + if (write(e->e_fd, newfile, (size_t) newsize) != newsize || + lseek(e->e_fd, (off_t) 0, SEEK_SET) < 0) { + LIBELF_SET_ERROR(IO, errno); + goto error; + } + + if (e->e_cmd != ELF_C_WRITE) { + if ((e->e_rawfile = mmap(NULL, (size_t) newsize, PROT_READ, + MAP_PRIVATE, e->e_fd, (off_t) 0)) == MAP_FAILED) { + LIBELF_SET_ERROR(IO, errno); + goto error; + } + e->e_rawsize = newsize; + } + + /* + * Reset flags, remove existing section descriptors and + * {E,P}HDR pointers so that a subsequent elf_get{e,p}hdr() + * and elf_getscn() will function correctly. + */ + + e->e_flags &= ~ELF_F_DIRTY; + + STAILQ_FOREACH_SAFE(scn, &e->e_u.e_elf.e_scn, s_next, tscn) + _libelf_release_scn(scn); + + if (ec == ELFCLASS32) { + free(e->e_u.e_elf.e_ehdr.e_ehdr32); + if (e->e_u.e_elf.e_phdr.e_phdr32) + free(e->e_u.e_elf.e_phdr.e_phdr32); + + e->e_u.e_elf.e_ehdr.e_ehdr32 = NULL; + e->e_u.e_elf.e_phdr.e_phdr32 = NULL; + } else { + free(e->e_u.e_elf.e_ehdr.e_ehdr64); + if (e->e_u.e_elf.e_phdr.e_phdr64) + free(e->e_u.e_elf.e_phdr.e_phdr64); + + e->e_u.e_elf.e_ehdr.e_ehdr64 = NULL; + e->e_u.e_elf.e_phdr.e_phdr64 = NULL; + } + + return (rc); + + error: + if (newfile) + free(newfile); + return ((off_t) -1); +} + +off_t +elf_update(Elf *e, Elf_Cmd c) +{ + int ec; + off_t rc; + + rc = (off_t) -1; + + if (e == NULL || e->e_kind != ELF_K_ELF || + (c != ELF_C_NULL && c != ELF_C_WRITE)) { + LIBELF_SET_ERROR(ARGUMENT, 0); + return (rc); + } + + if ((ec = e->e_class) != ELFCLASS32 && ec != ELFCLASS64) { + LIBELF_SET_ERROR(CLASS, 0); + return (rc); + } + + if (e->e_version == EV_NONE) + e->e_version = EV_CURRENT; + + if (c == ELF_C_WRITE && e->e_cmd == ELF_C_READ) { + LIBELF_SET_ERROR(MODE, 0); + return (rc); + } + + if ((rc = _libelf_resync_elf(e)) < 0) + return (rc); + + if (c == ELF_C_NULL) + return (rc); + + if (e->e_cmd == ELF_C_READ) { + /* + * This descriptor was opened in read-only mode or by + * elf_memory(). + */ + if (e->e_fd) + LIBELF_SET_ERROR(MODE, 0); + else + LIBELF_SET_ERROR(ARGUMENT, 0); + return ((off_t) -1); + } + + if (e->e_fd < 0) { + LIBELF_SET_ERROR(SEQUENCE, 0); + return ((off_t) -1); + } + + return (_libelf_write_elf(e, rc)); +} |