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| Current File : //compat/linux/proc/68247/cwd/usr/src/lib/libelf/elf_update.c |
/*-
* Copyright (c) 2006-2008 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/cdefs.h>
__FBSDID("$FreeBSD: release/9.1.0/lib/libelf/elf_update.c 212373 2010-09-09 18:51:50Z kaiw $");
#include <sys/mman.h>
#include <sys/param.h>
#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 data
* descriptors associated with it. The function returns zero if an
* error was detected. `*rc' holds the maximum file extent seen so
* far.
*/
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 > ELF_T_LAST) {
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) == 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 = roundup2(scn_size, d->d_align);
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;
if (tmax <= smin) {
/*
* 't' lies entirely before 's': ...| t |...| s |...
*/
prevt = t;
continue;
} else if (smax <= tmin)
/*
* 's' lies entirely before 't', and after 'prevt':
* ...| prevt |...| s |...| t |...
*/
break;
else { /* 's' and 't' overlap. */
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, shdr_start, shdr_end;
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;
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;
}
/*
* If the application is controlling file layout, check for an
* overlap between this section's extents and the SHDR table.
*/
if (e->e_flags & ELF_F_LAYOUT) {
if (e->e_class == ELFCLASS32)
shdr_start = e->e_u.e_elf.e_ehdr.e_ehdr32->e_shoff;
else
shdr_start = e->e_u.e_elf.e_ehdr.e_ehdr64->e_shoff;
shdr_end = shdr_start + _libelf_fsize(ELF_T_SHDR, e->e_class,
e->e_version, e->e_u.e_elf.e_nscn);
STAILQ_FOREACH(s, &e->e_u.e_elf.e_scn, s_next) {
if (s->s_offset >= shdr_end ||
s->s_offset + s->s_size <= shdr_start)
continue;
LIBELF_SET_ERROR(LAYOUT, 0);
return ((off_t) -1);
}
}
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 = (phnum == 0) ? 0 : _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 (e->e_cmd != ELF_C_WRITE &&
(e->e_flags & LIBELF_F_SHDRS_LOADED) == 0 &&
_libelf_load_scn(e, ehdr) == 0)
return ((off_t) -1);
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 ELF_F_LAYOUT is asserted, the
* application may have placed the section header table in
* between existing sections, so the net size of the file need
* not increase due to the presence of the section header
* table.
*/
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 (shoff % align) {
LIBELF_SET_ERROR(LAYOUT, 0);
return ((off_t) -1);
}
} else
shoff = roundup(rc, align);
if (shoff + fsz * shnum > (size_t) rc)
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, sh_size;
int elftype;
Elf_Data *d, dst;
if ((ec = e->e_class) == ELFCLASS32) {
sh_type = s->s_shdr.s_shdr32.sh_type;
sh_size = (uint64_t) s->s_shdr.s_shdr32.sh_size;
} else {
sh_type = s->s_shdr.s_shdr64.sh_type;
sh_size = s->s_shdr.s_shdr64.sh_size;
}
/*
* Ignore sections that do not allocate space in the file.
*/
if (sh_type == SHT_NOBITS || sh_type == SHT_NULL || sh_size == 0)
return (rc);
elftype = _libelf_xlate_shtype(sh_type);
assert(elftype >= ELF_T_FIRST && elftype <= ELF_T_LAST);
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) {
msz = _libelf_msize(d->d_type, ec, e->e_version);
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_version == e->e_version);
assert(d->d_size % msz == 0);
nobjects = d->d_size / msz;
fsz = _libelf_fsize(d->d_type, 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 maxrc, 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_buf = _libelf_getphdr(e, ec);
src.d_version = dst.d_version = e->e_version;
src.d_type = ELF_T_PHDR;
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. Note that
* if flag ELF_F_LAYOUT has been set the section header table
* could reside in between byte ranges mapped by section
* descriptors.
*/
if (shnum != 0 && shoff != 0) {
if ((uint64_t) rc < shoff)
(void) memset(newfile + rc,
LIBELF_PRIVATE(fillchar), shoff - rc);
maxrc = 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 + scn->s_ndx * fsz;
if (_libelf_xlate(&dst, &src, e->e_byteorder, ec,
ELF_TOFILE) != &dst)
goto error;
}
rc += e->e_u.e_elf.e_nscn * fsz;
if (maxrc > rc)
rc = maxrc;
}
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;
}
free(newfile);
return (rc);
error:
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));
}