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>
diff --git a/util/cbfstool/elfheaders.c b/util/cbfstool/elfheaders.c
index 03d8e7d..94c16b0 100644
--- a/util/cbfstool/elfheaders.c
+++ b/util/cbfstool/elfheaders.c
@@ -251,13 +251,16 @@
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 @@
*/
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 @@
/* 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 @@
*/
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 @@
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 @@
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 @@
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;
}
diff --git a/util/cbfstool/elfparsing.h b/util/cbfstool/elfparsing.h
index 3cfa1cd..4ad46b3 100644
--- a/util/cbfstool/elfparsing.h
+++ b/util/cbfstool/elfparsing.h
@@ -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,