Aaron Durbin (adurbin@google.com) just uploaded a new patch set to gerrit, which you can find at http://review.coreboot.org/5374
-gerrit
commit db1457cba671b80b7864e8f6e986af446de19e52 Author: Aaron Durbin adurbin@chromium.org Date: Wed Mar 5 13:57:30 2014 -0600
cbfstool: add relocation parsing to ELF parser
Optionally parse the relocation entries found within an ELF file.
Change-Id: I343647f104901eb8a6a997ddf44aa5d36c31b44b Signed-off-by: Aaron Durbin adurbin@chromium.org --- util/cbfstool/elfheaders.c | 87 ++++++++++++++++++++++++++++++++++++++++++++++ util/cbfstool/elfparsing.h | 10 ++++++ 2 files changed, 97 insertions(+)
diff --git a/util/cbfstool/elfheaders.c b/util/cbfstool/elfheaders.c index 94c16b0..8e06f5e 100644 --- a/util/cbfstool/elfheaders.c +++ b/util/cbfstool/elfheaders.c @@ -322,6 +322,79 @@ shdr_read(const struct buffer *in, struct parsed_elf *pelf, return 0; }
+static int +reloc_read(const struct buffer *in, struct parsed_elf *pelf, + struct xdr *xdr, int bit64) +{ + struct buffer b; + Elf64_Word i; + Elf64_Ehdr *ehdr; + + ehdr = &pelf->ehdr; + pelf->relocs = calloc(ehdr->e_shnum, sizeof(Elf64_Rela *)); + + /* Allocate array for each section that contains relocation entries. */ + for (i = 0; i < ehdr->e_shnum; i++) { + Elf64_Shdr *shdr; + Elf64_Rela *rela; + Elf64_Xword j; + Elf64_Xword nrelocs; + int is_rela; + + shdr = &pelf->shdr[i]; + + /* Only process REL and RELA sections. */ + if (shdr->sh_type != SHT_REL && shdr->sh_type != SHT_RELA) + continue; + + DEBUG("Checking relocation section %u\n", i); + + /* Ensure the section that relocations apply is a valid. */ + if (shdr->sh_info >= ehdr->e_shnum || + shdr->sh_info == SHN_UNDEF) { + ERROR("Relocations apply to an invalid section: %u\n", + shdr[i].sh_info); + return -1; + } + + is_rela = shdr->sh_type == SHT_RELA; + + /* Determine the number relocations in this section. */ + nrelocs = shdr->sh_size / shdr->sh_entsize; + + pelf->relocs[i] = calloc(nrelocs, sizeof(Elf64_Rela)); + + buffer_splice(&b, in, shdr->sh_offset, shdr->sh_size); + if (check_size(in, shdr->sh_offset, buffer_size(&b), + "relocation section")) { + ERROR("Relocation section %u failed.\n", i); + return -1; + } + + rela = pelf->relocs[i]; + for (j = 0; j < nrelocs; j++) { + if (bit64) { + rela->r_offset = xdr->get64(&b); + rela->r_info = xdr->get64(&b); + if (is_rela) + rela->r_addend = xdr->get64(&b); + } else { + uint32_t r_info; + + rela->r_offset = xdr->get32(&b); + r_info = xdr->get32(&b); + rela->r_info = ELF64_R_INFO(ELF32_R_SYM(r_info), + ELF32_R_TYPE(r_info)); + if (is_rela) + rela->r_addend = xdr->get32(&b); + } + rela++; + } + } + + return 0; +} + int parse_elf(const struct buffer *pinput, struct parsed_elf *pelf, int flags) { struct xdr *xdr = &xdr_le; @@ -351,12 +424,19 @@ int parse_elf(const struct buffer *pinput, struct parsed_elf *pelf, int flags)
elf_ehdr(&input, ehdr, xdr, bit64);
+ /* Relocation processing requires section header parsing. */ + if (flags & ELF_PARSE_RELOC) + flags |= ELF_PARSE_SHDR; + if ((flags & ELF_PARSE_PHDR) && phdr_read(pinput, pelf, xdr, bit64)) goto fail;
if ((flags & ELF_PARSE_SHDR) && shdr_read(pinput, pelf, xdr, bit64)) goto fail;
+ if ((flags & ELF_PARSE_RELOC) && reloc_read(pinput, pelf, xdr, bit64)) + goto fail; + return 0;
fail: @@ -368,6 +448,13 @@ void parsed_elf_destroy(struct parsed_elf *pelf) { free(pelf->phdr); free(pelf->shdr); + if (pelf->relocs != NULL) { + Elf64_Half i; + + for (i = 0; i < pelf->ehdr.e_shnum; i++) + free(pelf->relocs[i]); + } + free(pelf->relocs); }
/* Get the headers from the buffer. diff --git a/util/cbfstool/elfparsing.h b/util/cbfstool/elfparsing.h index 4ad46b3..2827748 100644 --- a/util/cbfstool/elfparsing.h +++ b/util/cbfstool/elfparsing.h @@ -26,10 +26,20 @@ struct parsed_elf { Elf64_Ehdr ehdr; Elf64_Phdr *phdr; Elf64_Shdr *shdr; + /* + * The relocs array contains pointers to arrays of relocation + * structures. Each index into the relocs array corresponds to its + * corresponding section index. i.e. if a section i is of type SHT_REL + * or SHT_RELA then the corresponding index into the relocs array will + * contain the associated relocations. Otherwise thee entry will be + * NULL. + */ + Elf64_Rela **relocs; };
#define ELF_PARSE_PHDR (1 << 0) #define ELF_PARSE_SHDR (1 << 1) +#define ELF_PARSE_RELOC (1 << 2)
#define ELF_PARSE_ALL (-1)