Hi Aaron,
On Mon, Jun 30, 2025 at 11:12:30PM -0400, Aaron Merey wrote:
> Signed-off-by: Aaron Merey <[email protected]>
> ---
> doc/Makefile.am | 1 +
> doc/elf_rawdata.3 | 97 +++++++++++++++++++++++++++++++++++++++++++++++
> 2 files changed, 98 insertions(+)
> create mode 100644 doc/elf_rawdata.3
>
> diff --git a/doc/Makefile.am b/doc/Makefile.am
> index 374e5d49..7d5a3eef 100644
> --- a/doc/Makefile.am
> +++ b/doc/Makefile.am
> @@ -83,6 +83,7 @@ notrans_dist_man3_MANS= elf32_checksum.3 \
> elf_newscn.3 \
> elf_nextscn.3 \
> elf_rand.3 \
> + elf_rawdata.3 \
> elf_update.3 \
> elf_version.3 \
> libelf.3
OK.
> diff --git a/doc/elf_rawdata.3 b/doc/elf_rawdata.3
> new file mode 100644
> index 00000000..c441edeb
> --- /dev/null
> +++ b/doc/elf_rawdata.3
> @@ -0,0 +1,97 @@
> +.TH ELF_RAWDATA 3 2025-06-30 "Libelf" "Libelf Programmer's Manual"
> +
> +.SH NAME
> +elf_rawdata - Retrieve unprocessed section data from an ELF descriptor.
... from an Elf section?
> +
> +.SH SYNOPSIS
> +.nf
> +#include <libelf.h>
> +
> +.BI "Elf_Data *elf_rawdata(Elf_Scn *" scn ", Elf_Data *" data ");"
> +.fi
OK.
> +.SH DESCRIPTION
> +The
> +.BR elf_rawdata ()
> +function returns a pointer to an
> +.B Elf_Data
> +structure containing the unprocessed (raw) contents of the section
> identified by
> +.IR scn .
> +This raw view reflects the exact binary layout in the ELF file, without any
> +conversion or translation.
That is a very long way to say the data is as on-disk. Maybe add
something about the difference with elf_getdata, which returns the
data translated into the in-memory format?
> +If
> +.I data
> +is
> +.B NULL ,
> +the raw data of the section is returned.
> +If
> +.I data
> +is not
> +.B NULL ,
> +and raw data has not been initialized, the call fails.
That last one surprised me. Although it makes sense, since it gets the
on-disk section contents there is only one buffer to represent that.
> +For compressed sections (i.e., with the
> +.B SHF_COMPRESSED
> +flag), the returned
> +.B Elf_Data
> +contains the compressed form, and its
> +.B d_type
> +is
> +.BR ELF_T_CHDR .
> +
> +For sections of type
> +.B SHT_NOBITS ,
> +the
> +.B d_buf
> +pointer is
> +.B NULL .
OK.
> +The data buffer may come directly from the memory-mapped file or may be
> +allocated and populated on first access.
Maybe the important thing is that the Elf_Data and d_buf pointer are
owned by libelf, should not be freed and are only valid till elf_end
is called?
> +.SH PARAMETERS
> +.TP
> +.I scn
> +A section descriptor returned from
> +.BR elf_getscn (3)
> +or
> +.BR elf_nextscn (3) .
> +Must not be
> +.B NULL .
If NULL, the call returns NULL.
> +.TP
> +.I data
> +Must be
> +.B NULL
> +on initial invocation. Any other use is not supported.
> +
> +.SH RETURN VALUE
> +Returns a pointer to an
> +.B Elf_Data
> +descriptor describing the raw contents of the section. On failure,
> +.B NULL
> +is returned.
OK.
> +.SH SEE ALSO
> +.BR elf_getdata (3),
> +.BR elf_getscn (3),
> +.BR elf_compress (3),
> +.BR libelf (3),
> +.BR elf (5)
> +
> +.SH ATTRIBUTES
> +.TS
> +allbox;
> +lbx lb lb
> +l l l.
> +Interface Attribute Value
> +T{
> +.na
> +.nh
> +.BR elf_rawdata ()
> +T} Thread safety MT-Safe
> +.TE
> +
> +.SH REPORTING BUGS
> +Report bugs to <[email protected]> or
> https://sourceware.org/bugzilla/.
OK.
Thanks,
Mark
