diff options
Diffstat (limited to 'linkers/elftoolchain/libelf/elf_strptr.c')
| -rw-r--r-- | linkers/elftoolchain/libelf/elf_strptr.c | 130 |
1 files changed, 130 insertions, 0 deletions
diff --git a/linkers/elftoolchain/libelf/elf_strptr.c b/linkers/elftoolchain/libelf/elf_strptr.c new file mode 100644 index 0000000..bfa39de --- /dev/null +++ b/linkers/elftoolchain/libelf/elf_strptr.c @@ -0,0 +1,130 @@ +/*- + * 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 <assert.h> +#include <gelf.h> + +#include "_libelf.h" + +LIBELF_VCSID("$Id: elf_strptr.c 189 2008-07-20 10:38:08Z jkoshy $"); + +/* + * Convert an ELF section#,offset pair to a string pointer. + */ + +char * +elf_strptr(Elf *e, size_t scndx, size_t offset) +{ + Elf_Scn *s; + Elf_Data *d; + size_t alignment, count; + GElf_Shdr shdr; + + if (e == NULL || e->e_kind != ELF_K_ELF) { + LIBELF_SET_ERROR(ARGUMENT, 0); + return (NULL); + } + + if ((s = elf_getscn(e, scndx)) == NULL || + gelf_getshdr(s, &shdr) == NULL) + return (NULL); + + if (shdr.sh_type != SHT_STRTAB || + offset >= shdr.sh_size) { + LIBELF_SET_ERROR(ARGUMENT, 0); + return (NULL); + } + + d = NULL; + if (e->e_flags & ELF_F_LAYOUT) { + + /* + * The application is taking responsibility for the + * ELF object's layout, so we can directly translate + * an offset to a `char *' address using the `d_off' + * members of Elf_Data descriptors. + */ + while ((d = elf_getdata(s, d)) != NULL) { + + if (d->d_buf == 0 || d->d_size == 0) + continue; + + if (d->d_type != ELF_T_BYTE) { + LIBELF_SET_ERROR(DATA, 0); + return (NULL); + } + + if (offset >= d->d_off && + offset < d->d_off + d->d_size) + return ((char *) d->d_buf + offset - d->d_off); + } + } else { + /* + * Otherwise, the `d_off' members are not useable and + * we need to compute offsets ourselves, taking into + * account 'holes' in coverage of the section introduced + * by alignment requirements. + */ + count = (size_t) 0; /* cumulative count of bytes seen */ + while ((d = elf_getdata(s, d)) != NULL && count <= offset) { + + if (d->d_buf == NULL || d->d_size == 0) + continue; + + if (d->d_type != ELF_T_BYTE) { + LIBELF_SET_ERROR(DATA, 0); + return (NULL); + } + + if ((alignment = d->d_align) > 1) { + if ((alignment & (alignment - 1)) != 0) { + LIBELF_SET_ERROR(DATA, 0); + return (NULL); + } + count = roundup2(count, alignment); + } + + if (offset < count) { + /* offset starts in the 'hole' */ + LIBELF_SET_ERROR(ARGUMENT, 0); + return (NULL); + } + + if (offset < count + d->d_size) { + if (d->d_buf != NULL) + return ((char *) d->d_buf + + offset - count); + LIBELF_SET_ERROR(DATA, 0); + return (NULL); + } + + count += d->d_size; + } + } + + LIBELF_SET_ERROR(ARGUMENT, 0); + return (NULL); +} |