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>
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@ -251,13 +251,16 @@ elf_shdr(struct buffer *pinput, Elf64_Shdr *shdr,
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buffer_seek(pinput, entsize);
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}
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static Elf64_Phdr *
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phdr_read(const struct buffer *in, Elf64_Ehdr *ehdr, struct xdr *xdr, int bit64)
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static int
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phdr_read(const struct buffer *in, struct parsed_elf *pelf,
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struct xdr *xdr, int bit64)
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{
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struct buffer b;
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Elf64_Phdr *phdr;
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Elf64_Ehdr *ehdr;
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int i;
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ehdr = &pelf->ehdr;
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/* cons up an input buffer for the headers.
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* Note that the program headers can be anywhere,
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* per the ELF spec, You'd be surprised how many ELF
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@ -265,7 +268,7 @@ phdr_read(const struct buffer *in, Elf64_Ehdr *ehdr, struct xdr *xdr, int bit64)
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*/
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buffer_splice(&b, in, ehdr->e_phoff, ehdr->e_phentsize * ehdr->e_phnum);
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if (check_size(in, ehdr->e_phoff, buffer_size(&b), "program headers"))
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return NULL;
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return -1;
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/* gather up all the phdrs.
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* We do them all at once because there is more
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@ -279,19 +282,25 @@ phdr_read(const struct buffer *in, Elf64_Ehdr *ehdr, struct xdr *xdr, int bit64)
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/* Ensure the contents are valid within the elf file. */
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if (check_size(in, phdr[i].p_offset, phdr[i].p_filesz,
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"segment contents"))
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return NULL;
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return -1;
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}
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return phdr;
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pelf->phdr = phdr;
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return 0;
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}
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static Elf64_Shdr *
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shdr_read(const struct buffer *in, Elf64_Ehdr *ehdr, struct xdr *xdr, int bit64)
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static int
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shdr_read(const struct buffer *in, struct parsed_elf *pelf,
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struct xdr *xdr, int bit64)
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{
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struct buffer b;
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Elf64_Shdr *shdr;
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Elf64_Ehdr *ehdr;
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int i;
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ehdr = &pelf->ehdr;
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/* cons up an input buffer for the section headers.
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* Note that the section headers can be anywhere,
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* per the ELF spec, You'd be surprised how many ELF
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@ -299,7 +308,7 @@ shdr_read(const struct buffer *in, Elf64_Ehdr *ehdr, struct xdr *xdr, int bit64)
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*/
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buffer_splice(&b, in, ehdr->e_shoff, ehdr->e_shentsize * ehdr->e_shnum);
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if (check_size(in, ehdr->e_shoff, buffer_size(&b), "section headers"))
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return NULL;
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return -1;
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/* gather up all the shdrs. */
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shdr = calloc(ehdr->e_shnum, sizeof(*shdr));
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@ -308,7 +317,57 @@ shdr_read(const struct buffer *in, Elf64_Ehdr *ehdr, struct xdr *xdr, int bit64)
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elf_shdr(&b, &shdr[i], ehdr->e_shentsize, xdr, bit64);
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}
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return shdr;
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pelf->shdr = shdr;
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return 0;
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}
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int parse_elf(const struct buffer *pinput, struct parsed_elf *pelf, int flags)
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{
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struct xdr *xdr = &xdr_le;
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int bit64 = 0;
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struct buffer input;
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Elf64_Ehdr *ehdr;
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/* Zero out the parsed elf structure. */
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memset(pelf, 0, sizeof(*pelf));
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if (!iself(buffer_get(pinput))) {
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ERROR("The stage file is not in ELF format!\n");
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return -1;
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}
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buffer_clone(&input, pinput);
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ehdr = &pelf->ehdr;
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elf_eident(&input, ehdr);
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bit64 = ehdr->e_ident[EI_CLASS] == ELFCLASS64;
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/* Assume LE unless we are sure otherwise.
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* We're not going to take on the task of
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* fully validating the ELF file. That way
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* lies madness.
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*/
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if (ehdr->e_ident[EI_DATA] == ELFDATA2MSB)
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xdr = &xdr_be;
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elf_ehdr(&input, ehdr, xdr, bit64);
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if ((flags & ELF_PARSE_PHDR) && phdr_read(pinput, pelf, xdr, bit64))
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goto fail;
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if ((flags & ELF_PARSE_SHDR) && shdr_read(pinput, pelf, xdr, bit64))
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goto fail;
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return 0;
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fail:
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parsed_elf_destroy(pelf);
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return -1;
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}
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void parsed_elf_destroy(struct parsed_elf *pelf)
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{
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free(pelf->phdr);
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free(pelf->shdr);
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}
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/* Get the headers from the buffer.
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@ -325,28 +384,20 @@ elf_headers(const struct buffer *pinput,
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Elf64_Phdr **pphdr,
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Elf64_Shdr **pshdr)
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{
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struct xdr *xdr = &xdr_le;
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int bit64 = 0;
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struct buffer input;
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buffer_clone(&input, pinput);
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struct parsed_elf pelf;
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int flags;
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if (!iself(buffer_get(pinput))) {
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ERROR("The stage file is not in ELF format!\n");
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flags = ELF_PARSE_PHDR;
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if (pshdr != NULL)
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flags |= ELF_PARSE_SHDR;
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if (parse_elf(pinput, &pelf, flags))
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return -1;
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}
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elf_eident(&input, ehdr);
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bit64 = ehdr->e_ident[EI_CLASS] == ELFCLASS64;
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/* Assume LE unless we are sure otherwise.
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* We're not going to take on the task of
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* fully validating the ELF file. That way
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* lies madness.
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*/
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if (ehdr->e_ident[EI_DATA] == ELFDATA2MSB)
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xdr = &xdr_be;
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elf_ehdr(&input, ehdr, xdr, bit64);
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/* Copy out the parsed elf header. */
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memcpy(ehdr, &pelf.ehdr, sizeof(*ehdr));
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// The tool may work in architecture-independent way.
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if (arch != CBFS_ARCHITECTURE_UNKNOWN &&
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@ -356,16 +407,15 @@ elf_headers(const struct buffer *pinput,
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return -1;
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}
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*pphdr = phdr_read(pinput, ehdr, xdr, bit64);
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if (*pphdr == NULL)
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return -1;
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*pphdr = calloc(ehdr->e_phnum, sizeof(Elf64_Phdr));
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memcpy(*pphdr, pelf.phdr, ehdr->e_phnum * sizeof(Elf64_Phdr));
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if (!pshdr)
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return 0;
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if (pshdr != NULL) {
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*pshdr = calloc(ehdr->e_shnum, sizeof(Elf64_Shdr));
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memcpy(*pshdr, pelf.shdr, ehdr->e_shnum * sizeof(Elf64_Shdr));
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}
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*pshdr = shdr_read(pinput, ehdr, xdr, bit64);
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if (*pshdr == NULL)
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return -1;
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parsed_elf_destroy(&pelf);
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return 0;
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}
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@ -22,6 +22,31 @@
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struct buffer;
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struct parsed_elf {
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Elf64_Ehdr ehdr;
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Elf64_Phdr *phdr;
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Elf64_Shdr *shdr;
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};
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#define ELF_PARSE_PHDR (1 << 0)
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#define ELF_PARSE_SHDR (1 << 1)
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#define ELF_PARSE_ALL (-1)
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/*
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* Parse an ELF file contained within provide struct buffer. The ELF header
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* is always parsed while the flags value containing the ELF_PARSE_* values
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* determine if other parts of the ELF file will be parsed as well.
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* Returns 0 on success, < 0 error.
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*/
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int parse_elf(const struct buffer *pinput, struct parsed_elf *pelf, int flags);
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/*
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* Clean up memory associated with parsed_elf.
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*/
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void parsed_elf_destroy(struct parsed_elf *pelf);
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int
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elf_headers(const struct buffer *pinput,
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uint32_t arch,
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