Date: Sat, 4 Nov 2006 04:27:17 GMT From: John Birrell <jb@FreeBSD.org> To: Perforce Change Reviews <perforce@freebsd.org> Subject: PERFORCE change 109210 for review Message-ID: <200611040427.kA44RHbE084332@repoman.freebsd.org>
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http://perforce.freebsd.org/chv.cgi?CH=109210 Change 109210 by jb@jb_freebsd8 on 2006/11/04 04:26:41 Manual merge frol libbsdelf. Affected files ... .. //depot/projects/dtrace/src/lib/libelf/elf_strptr.c#3 edit Differences ... ==== //depot/projects/dtrace/src/lib/libelf/elf_strptr.c#3 (text+ko) ==== @@ -1,5 +1,5 @@ /*- - * Copyright (c) 2006 John Birrell jb@freebsd.org + * Copyright (c) 2006 Joseph Koshy * All rights reserved. * * Redistribution and use in source and binary forms, with or without @@ -27,14 +27,97 @@ #include <sys/cdefs.h> __FBSDID("$FreeBSD$"); -#include <libelf.h> -#include <stdio.h> +#include <sys/param.h> + +#include <assert.h> +#include <gelf.h> #include "_libelf.h" +/* + * Convert an ELF section#,offset pair to a string pointer. + */ + char * -elf_strptr(__unused Elf *elf, __unused size_t section, __unused size_t offset) +elf_strptr(Elf *e, size_t scn, size_t offset) { - printf("%s: not implemented\n", __FUNCTION__); + 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, scn)) == 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; + assert(d->d_type == ELF_T_BYTE); + 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 by the + * chain of Elf_Data descriptors. + */ + count = 0; /* cumulative count of bytes seen */ + while ((d = elf_getdata(s, d)) == NULL && + count <= offset) { + + assert(d->d_type == ELF_T_BYTE); + + 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); } +
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