[coreboot-gerrit] New patch to review for coreboot: 295df42 cbfstool: add string table parsing to ELF parser

[Aaron Durbin]

Aaron Durbin ([e-mail]) just uploaded a new patch set to gerrit, which you can find at http://review.coreboot.org/5375

-gerrit

commit 295df4284ccd39c1bfce0081906517f66781d19f
Author: Aaron Durbin 
Date:   Wed Mar 5 14:33:42 2014 -0600

cbfstool: add string table parsing to ELF parser

Optionally parse the string tables within an ELF file.

Change-Id: I89f9da50b4fcf1fed7ac44f00c60b495c35555ef
    Signed-off-by: Aaron Durbin 
---
 util/cbfstool/elfheaders.c | 52 ++++++++++++++++++++++++++++++++++++++++++++--
 util/cbfstool/elfparsing.h | 11 ++++++++--
 2 files changed, 59 insertions(+), 4 deletions(-)

diff --git a/util/cbfstool/elfheaders.c b/util/cbfstool/elfheaders.c
index d36dfbb..fe64e17 100644
--- a/util/cbfstool/elfheaders.c
+++ b/util/cbfstool/elfheaders.c
@@ -400,6 +400,41 @@ reloc_read(const struct buffer *in, struct parsed_elf *pelf,
    return 0;
 }

+static int strtab_read(const struct buffer *in, struct parsed_elf *pelf)
+{
+	Elf64_Ehdr *ehdr;
+	Elf64_Word i;
+
+	ehdr = &pelf->ehdr;
+
+	if (ehdr->e_shstrndx >= ehdr->e_shnum) {
+		ERROR("Section header string table index out of range: %d\n",
+		      ehdr->e_shstrndx);
+		return -1;
+	}
+
+	/* For each section of type SHT_STRTAB create a symtab buffer. */
+	pelf->strtabs = calloc(ehdr->e_shnum, sizeof(struct buffer *));
+
+	for (i = 0; i < ehdr->e_shnum; i++) {
+		struct buffer *b;
+		Elf64_Shdr *shdr = &pelf->shdr[i];
+
+		if (shdr->sh_type != SHT_STRTAB)
+			continue;
+
+		b = calloc(1, sizeof(*b));
+		buffer_splice(b, in, shdr->sh_offset, shdr->sh_size);
+		if (check_size(in, shdr->sh_offset, buffer_size(b), "strtab")) {
+			ERROR("STRTAB section not within bounds: %d\n", i);
+			return -1;
+		}
+		pelf->strtabs[i] = b;
+	}
+
+	return 0;
+}
+
 int parse_elf(const struct buffer *pinput, struct parsed_elf *pelf, int flags)
 {
    struct xdr *xdr = &xdr_le;
@@ -433,6 +468,10 @@ int parse_elf(const struct buffer *pinput, struct parsed_elf *pelf, int flags)
    if (flags & ELF_PARSE_RELOC)
    	flags |= ELF_PARSE_SHDR;

+	/* String table processing requires section header parsing. */
+	if (flags & ELF_PARSE_STRTAB)
+		flags |= ELF_PARSE_SHDR;
+
    if ((flags & ELF_PARSE_PHDR) && phdr_read(pinput, pelf, xdr, bit64))
    	goto fail;

@@ -442,6 +481,9 @@ int parse_elf(const struct buffer *pinput, struct parsed_elf *pelf, int flags)
    if ((flags & ELF_PARSE_RELOC) && reloc_read(pinput, pelf, xdr, bit64))
    	goto fail;

+	if ((flags & ELF_PARSE_STRTAB) && strtab_read(pinput, pelf))
+		goto fail;
+
    return 0;

fail:
@@ -451,15 +493,21 @@ fail:

void parsed_elf_destroy(struct parsed_elf *pelf)
 {
+	Elf64_Half i;
+
    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);
+
+	if (pelf->strtabs != NULL) {
+		for (i = 0; i < pelf->ehdr.e_shnum; i++)
+			free(pelf->strtabs[i]);
+	}
+	free(pelf->strtabs);
 }

/* Get the headers from the buffer.
diff --git a/util/cbfstool/elfparsing.h b/util/cbfstool/elfparsing.h
index 2827748..9107c21 100644
--- a/util/cbfstool/elfparsing.h
+++ b/util/cbfstool/elfparsing.h
@@ -19,8 +19,7 @@
 #define ELFPARSING_H

#include "elf.h"
-
-struct buffer;
+#include "common.h"

struct parsed_elf {
    Elf64_Ehdr ehdr;
@@ -35,11 +34,19 @@ struct parsed_elf {
     * NULL.
     */
    Elf64_Rela **relocs;
+	/*
+	 * Similarly to the relocs array the strtabs array consists of an
+	 * array of pointers where each entry represents a potential struct
+	 * buffer pointer. Only setions of type SHT_STRTAB will have a non-NULL
+	 * entry.
+	 */
+	struct buffer **strtabs;
 };

#define ELF_PARSE_PHDR		(1 << 0)
 #define ELF_PARSE_SHDR		(1 << 1)
 #define ELF_PARSE_RELOC		(1 << 2)
+#define ELF_PARSE_STRTAB	(1 << 3)

#define ELF_PARSE_ALL		(-1)