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cbfstool: introduce struct parsed_elf and parse_elf() 

In order to make the ELF parsing more flexible introduce
a parse_elf() function which takes a struct parsed_elf
parameter. In addition take a flags parameter which instructs
the ELF parser as to what data within the ELF file should be
parsed.

Change-Id: I3e30e84bf8043c3df96a6ab56cd077eef2632173
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: http://review.coreboot.org/5373
Tested-by: build bot (Jenkins)
Reviewed-by: Marc Jones <marc.jones@se-eng.com>
This commit is contained in:
Aaron Durbin 2014-03-05 13:09:55 -06:00 committed by Aaron Durbin
parent 19a11d6fe9
commit d0f6165923
2 changed files with 110 additions and 35 deletions
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120
util/cbfstool/elfheaders.c
View File

@ -251,13 +251,16 @@ elf_shdr(struct buffer *pinput, Elf64_Shdr *shdr,
buffer_seek(pinput, entsize);
}
static Elf64_Phdr *
phdr_read(const struct buffer *in, Elf64_Ehdr *ehdr, struct xdr *xdr, int bit64)
static int
phdr_read(const struct buffer *in, struct parsed_elf *pelf,
struct xdr *xdr, int bit64)
{
struct buffer b;
Elf64_Phdr *phdr;
Elf64_Ehdr *ehdr;
int i;
ehdr = &pelf->ehdr;
/* cons up an input buffer for the headers.
* Note that the program headers can be anywhere,
* per the ELF spec, You'd be surprised how many ELF
@ -265,7 +268,7 @@ phdr_read(const struct buffer *in, Elf64_Ehdr *ehdr, struct xdr *xdr, int bit64)
*/
buffer_splice(&b, in, ehdr->e_phoff, ehdr->e_phentsize * ehdr->e_phnum);
if (check_size(in, ehdr->e_phoff, buffer_size(&b), "program headers"))
return NULL;
return -1;
/* gather up all the phdrs.
* We do them all at once because there is more
@ -279,19 +282,25 @@ phdr_read(const struct buffer *in, Elf64_Ehdr *ehdr, struct xdr *xdr, int bit64)
/* Ensure the contents are valid within the elf file. */
if (check_size(in, phdr[i].p_offset, phdr[i].p_filesz,
"segment contents"))
return NULL;
return -1;
}
return phdr;
pelf->phdr = phdr;
return 0;
}
static Elf64_Shdr *
shdr_read(const struct buffer *in, Elf64_Ehdr *ehdr, struct xdr *xdr, int bit64)
static int
shdr_read(const struct buffer *in, struct parsed_elf *pelf,
struct xdr *xdr, int bit64)
{
struct buffer b;
Elf64_Shdr *shdr;
Elf64_Ehdr *ehdr;
int i;
ehdr = &pelf->ehdr;
/* cons up an input buffer for the section headers.
* Note that the section headers can be anywhere,
* per the ELF spec, You'd be surprised how many ELF
@ -299,7 +308,7 @@ shdr_read(const struct buffer *in, Elf64_Ehdr *ehdr, struct xdr *xdr, int bit64)
*/
buffer_splice(&b, in, ehdr->e_shoff, ehdr->e_shentsize * ehdr->e_shnum);
if (check_size(in, ehdr->e_shoff, buffer_size(&b), "section headers"))
return NULL;
return -1;
/* gather up all the shdrs. */
shdr = calloc(ehdr->e_shnum, sizeof(*shdr));
@ -308,7 +317,57 @@ shdr_read(const struct buffer *in, Elf64_Ehdr *ehdr, struct xdr *xdr, int bit64)
elf_shdr(&b, &shdr[i], ehdr->e_shentsize, xdr, bit64);
}
return shdr;
pelf->shdr = shdr;
return 0;
}
int parse_elf(const struct buffer *pinput, struct parsed_elf *pelf, int flags)
{
struct xdr *xdr = &xdr_le;
int bit64 = 0;
struct buffer input;
Elf64_Ehdr *ehdr;
/* Zero out the parsed elf structure. */
memset(pelf, 0, sizeof(*pelf));
if (!iself(buffer_get(pinput))) {
ERROR("The stage file is not in ELF format!\n");
return -1;
}
buffer_clone(&input, pinput);
ehdr = &pelf->ehdr;
elf_eident(&input, ehdr);
bit64 = ehdr->e_ident[EI_CLASS] == ELFCLASS64;
/* Assume LE unless we are sure otherwise.
* We're not going to take on the task of
* fully validating the ELF file. That way
* lies madness.
*/
if (ehdr->e_ident[EI_DATA] == ELFDATA2MSB)
xdr = &xdr_be;
elf_ehdr(&input, ehdr, xdr, bit64);
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;
return 0;
fail:
parsed_elf_destroy(pelf);
return -1;
}
void parsed_elf_destroy(struct parsed_elf *pelf)
{
free(pelf->phdr);
free(pelf->shdr);
}
/* Get the headers from the buffer.
@ -325,28 +384,20 @@ elf_headers(const struct buffer *pinput,
Elf64_Phdr **pphdr,
Elf64_Shdr **pshdr)
{
struct xdr *xdr = &xdr_le;
int bit64 = 0;
struct buffer input;
buffer_clone(&input, pinput);
struct parsed_elf pelf;
int flags;
if (!iself(buffer_get(pinput))) {
ERROR("The stage file is not in ELF format!\n");
flags = ELF_PARSE_PHDR;
if (pshdr != NULL)
flags |= ELF_PARSE_SHDR;
if (parse_elf(pinput, &pelf, flags))
return -1;
}
elf_eident(&input, ehdr);
bit64 = ehdr->e_ident[EI_CLASS] == ELFCLASS64;
/* Assume LE unless we are sure otherwise.
* We're not going to take on the task of
* fully validating the ELF file. That way
* lies madness.
*/
if (ehdr->e_ident[EI_DATA] == ELFDATA2MSB)
xdr = &xdr_be;
elf_ehdr(&input, ehdr, xdr, bit64);
/* Copy out the parsed elf header. */
memcpy(ehdr, &pelf.ehdr, sizeof(*ehdr));
// The tool may work in architecture-independent way.
if (arch != CBFS_ARCHITECTURE_UNKNOWN &&
@ -356,16 +407,15 @@ elf_headers(const struct buffer *pinput,
return -1;
}
*pphdr = phdr_read(pinput, ehdr, xdr, bit64);
if (*pphdr == NULL)
return -1;
*pphdr = calloc(ehdr->e_phnum, sizeof(Elf64_Phdr));
memcpy(*pphdr, pelf.phdr, ehdr->e_phnum * sizeof(Elf64_Phdr));
if (!pshdr)
return 0;
if (pshdr != NULL) {
*pshdr = calloc(ehdr->e_shnum, sizeof(Elf64_Shdr));
memcpy(*pshdr, pelf.shdr, ehdr->e_shnum * sizeof(Elf64_Shdr));
}
*pshdr = shdr_read(pinput, ehdr, xdr, bit64);
if (*pshdr == NULL)
return -1;
parsed_elf_destroy(&pelf);
return 0;
}

25
util/cbfstool/elfparsing.h
View File

@ -22,6 +22,31 @@
struct buffer;
struct parsed_elf {
Elf64_Ehdr ehdr;
Elf64_Phdr *phdr;
Elf64_Shdr *shdr;
};
#define ELF_PARSE_PHDR (1 << 0)
#define ELF_PARSE_SHDR (1 << 1)
#define ELF_PARSE_ALL (-1)
/*
* Parse an ELF file contained within provide struct buffer. The ELF header
* is always parsed while the flags value containing the ELF_PARSE_* values
* determine if other parts of the ELF file will be parsed as well.
* Returns 0 on success, < 0 error.
*/
int parse_elf(const struct buffer *pinput, struct parsed_elf *pelf, int flags);
/*
* Clean up memory associated with parsed_elf.
*/
void parsed_elf_destroy(struct parsed_elf *pelf);
int
elf_headers(const struct buffer *pinput,
uint32_t arch,