[PATCH 3/7 v3] doc: Add elf_next.3
Signed-off-by: Aaron Merey
---
v3 changes: Use .B for EXAMPLES.
On Fri, Jun 27, 2025 at 6:36 PM Mark Wielaard wrote:
> > + /* Get the members of the archive one after the other. */
> > + while ((subelf = elf_begin (fd, cmd, elf)) != NULL)
> > + {
> > + /* Process subelf here */
> > + [...]
> > +
> > + /* Get next archive element. */
> > + cmd = elf_next (subelf);
> > + if (elf_end (subelf) != 0)
> > + {
> > + printf ("error while freeing sub-ELF descriptor: %s\\n",
> > + elf_errmsg (-1));
> > + exit (1);
> > + }
> > + }
> > +
> > + elf_end (elf);
> > + close (fd);
> > +.fi
>
> Should you check the cmd after the elf_next call?
cmd is checked by elf_begin which terminates the loop when cmd is
ELF_C_NULL.
doc/Makefile.am | 1 +
doc/elf_next.3 | 122
2 files changed, 123 insertions(+)
create mode 100644 doc/elf_next.3
diff --git a/doc/Makefile.am b/doc/Makefile.am
index 1ced7858..fbfebfe0 100644
--- a/doc/Makefile.am
+++ b/doc/Makefile.am
@@ -61,6 +61,7 @@ notrans_dist_man3_MANS= elf32_checksum.3 \
elf_hash.3 \
elf_kind.3 \
elf_ndxscn.3 \
+ elf_next.3 \
elf_update.3 \
elf_version.3 \
libelf.3
diff --git a/doc/elf_next.3 b/doc/elf_next.3
new file mode 100644
index ..4d8c16d2
--- /dev/null
+++ b/doc/elf_next.3
@@ -0,0 +1,122 @@
+.TH ELF_NEXT 3 2025-06-06 "Libelf" "Libelf Programmer's Manual"
+
+.SH NAME
+elf_next \- advance an ELF descriptor to the next archive member
+
+.SH SYNOPSIS
+.nf
+.B #include
+
+.BI "Elf_Cmd elf_next(Elf *" elf ");"
+.fi
+.SH DESCRIPTION
+Advance an ELF descriptor associated with an archive file to the next available
+archive member.
+
+.P
+ELF descriptors initialized from an archive file can be used to retrieve ELF
+descriptors for archive members one at a time using
+.BR elf_begin .
+.B elf_next
+updates the archive descriptor so that
+.B elf_begin
+may return the ELF descriptor of the next member of the archive.
+.B elf_next
+is called with a archive member's ELF descriptor and updates descriptor
+of the parent archive (see the
+.B EXAMPLES
+section below).
+
+.SH RETURN VALUE
+If
+.I elf
+refers to an archive member, update the state of the parent archive
+ELF descriptor associated with
+.I elf
+so that the next archive member can be retrieved with
+.BR elf_begin .
+Return the
+.B Elf_Cmd
+that was used with
+.B elf_begin
+to initialize
+.IR elf .
+
+.P
+If
+.I elf
+was not initialized from an archive file or there are no more archive members,
+.B elf_next
+returns
+.B ELF_C_NULL.
+
+.SH EXAMPLES
+.nf
+ /* Open the archive. */
+ fd = open (archive_name, O_RDONLY);
+ if (fd == -1)
+{
+ printf ("cannot open archive file `%s'", fname);
+ exit (1);
+}
+
+ /* Set the ELF version. */
+ elf_version (EV_CURRENT);
+
+ /* Create an ELF descriptor for the archive. */
+ cmd = ELF_C_READ;
+ elf = elf_begin (fd, cmd, NULL);
+ if (elf == NULL)
+{
+ printf ("cannot create ELF descriptor: %s\\n", elf_errmsg (-1));
+ exit (1);
+}
+
+ /* Verify this is a descriptor for an archive. */
+ if (elf_kind (elf) != ELF_K_AR)
+{
+ printf ("`%s' is not an archive\\n", fname);
+ exit (1);
+}
+
+ /* Get the members of the archive one after the other. */
+ while ((subelf = elf_begin (fd, cmd, elf)) != NULL)
+{
+ /* Process subelf here */
+ [...]
+
+ /* Get next archive element. */
+ cmd = elf_next (subelf);
+ if (elf_end (subelf) != 0)
+{
+ printf ("error while freeing sub-ELF descriptor: %s\\n",
+ elf_errmsg (-1));
+ exit (1);
+}
+}
+
+ elf_end (elf);
+ close (fd);
+.fi
+
+.SH SEE ALSO
+.BR elf_begin (3),
+.BR elf_rand (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_next ()
+T} Thread safety MT-Safe
+.TE
+
+.SH REPORTING BUGS
+Report bugs to or
https://sourceware.org/bugzilla/.
--
2.50.0
[PATCH 6/7 v3] doc: Add elf_cntl.3
Signed-off-by: Aaron Merey
---
v3: Clarify that future operations might fail after ELF_C_FDDONE
unless ELF_C_FDREAD is used first.
doc/Makefile.am | 1 +
doc/elf_cntl.3 | 70 +
2 files changed, 71 insertions(+)
create mode 100644 doc/elf_cntl.3
diff --git a/doc/Makefile.am b/doc/Makefile.am
index aae29ebc..486d9f22 100644
--- a/doc/Makefile.am
+++ b/doc/Makefile.am
@@ -51,6 +51,7 @@ notrans_dist_man3_MANS= elf32_checksum.3 \
elf64_xlatetom.3 \
elf_begin.3 \
elf_clone.3 \
+ elf_cntl.3 \
elf_end.3 \
elf_errmsg.3 \
elf_errno.3 \
diff --git a/doc/elf_cntl.3 b/doc/elf_cntl.3
new file mode 100644
index ..58a3e5c7
--- /dev/null
+++ b/doc/elf_cntl.3
@@ -0,0 +1,70 @@
+.TH ELF_CNTL 3 2025-06-17 "Libelf" "Libelf Programmer's Manual"
+
+.SH NAME
+elf_cntl \- perform control operations on an ELF descriptor
+
+.SH SYNOPSIS
+.nf
+#include
+
+int elf_cntl(Elf *elf, Elf_Cmd cmd);
+.fi
+.SH DESCRIPTION
+Perform control operations on the ELF descriptor
+.I elf
+according to the operation specified by
+.IR cmd .
+
+The following commands are supported:
+
+.TP
+.B ELF_C_FDDONE
+This command tells
+.B libelf
+that the application is done using the file descriptor associated with the
+.I elf
+object. The file descriptor may then be closed immediately without affecting
the
+in-memory ELF data. Unless all data has been read from the file descriptor
(see
+.B ELF_C_FDREAD
+below) future operation on the Elf descriptor may fail.
+
+.TP
+.B ELF_C_FDREAD
+This command causes
+.B libelf
+to read the entire contents of the underlying file into memory immediately.
+.B libelf
+generally reads and parses elements of ELF files only when they are required.
+This command instead triggers
+.B libelf
+to read all elements immediately. Using this command ensures that
+.B ELF_C_FDDONE
+may be used without causing future operations on the Elf descriptor to fail.
+
+.SH RETURN VALUE
+On success, returns 0.
+
+On failure, it returns \-1 and sets an error that can be retrieved with
+.BR elf_errmsg (3).
+
+
+.SH SEE ALSO
+.BR libelf (3),
+.BR elf_errmsg (3),
+.BR elf (5)
+
+.SH ATTRIBUTES
+.TS
+allbox;
+lbx lb lb
+l l l.
+Interface Attribute Value
+T{
+.na
+.nh
+.BR elf_cntl ()
+T} Thread safety MT-Safe
+.TE
+
+.SH REPORTING BUGS
+Report bugs to or
https://sourceware.org/bugzilla/.
--
2.50.0
[PATCH 2/7] elf_getarhdr: Replace per-archive Elf_Arhdr storage with per-member storage
Currently each archive descriptor maintains a single Elf_Arhdr for the
current archive member (as determined by elf_next or elf_rand) which is
returned by elf_getarhdr.
A single per-archive Elf_Arhdr is not ideal since elf_next and elf_rand
can invalidate an archive member's reference to its own Elf_Arhdr.
Avoid this possible invalidation by storing each Elf_Arhdr in its
archive member descriptor.
The existing Elf_Arhdr parsing and storage in the archive descriptor
internal state is left mostly untouched. When an archive member is
created with elf_begin it is given its own copy of its Elf_Arhdr from
the archive descriptor.
Also update tests/arextract.c with verification that each Elf_Arhdr
is distinct and remains valid after calls to elf_next that would
have previously invalidated the Elf_Arhdr.
Signed-off-by: Aaron Merey
---
libelf/elf_begin.c| 5 +++-
libelf/elf_clone.c| 1 +
libelf/elf_getarhdr.c | 22 ++
libelf/libelfP.h | 3 ++
tests/arextract.c | 68 ++-
5 files changed, 70 insertions(+), 29 deletions(-)
diff --git a/libelf/elf_begin.c b/libelf/elf_begin.c
index 3ed1f8d7..5ed5aaa3 100644
--- a/libelf/elf_begin.c
+++ b/libelf/elf_begin.c
@@ -1065,11 +1065,14 @@ dup_elf (int fildes, Elf_Cmd cmd, Elf *ref)
result = read_file (fildes, ref->state.ar.offset + sizeof (struct ar_hdr),
ref->state.ar.elf_ar_hdr.ar_size, cmd, ref);
- /* Enlist this new descriptor in the list of children. */
if (result != NULL)
{
+ /* Enlist this new descriptor in the list of children. */
result->next = ref->state.ar.children;
ref->state.ar.children = result;
+
+ /* Ensure the member descriptor has its own copy of its header info. */
+ result->elf_ar_hdr = ref->state.ar.elf_ar_hdr;
}
return result;
diff --git a/libelf/elf_clone.c b/libelf/elf_clone.c
index e6fe4729..d6c8d541 100644
--- a/libelf/elf_clone.c
+++ b/libelf/elf_clone.c
@@ -69,6 +69,7 @@ elf_clone (Elf *elf, Elf_Cmd cmd)
== offsetof (struct Elf, state.elf64.scns));
retval->state.elf.scns_last = &retval->state.elf32.scns;
retval->state.elf32.scns.max = elf->state.elf32.scns.max;
+ retval->elf_ar_hdr = elf->elf_ar_hdr;
retval->class = elf->class;
}
diff --git a/libelf/elf_getarhdr.c b/libelf/elf_getarhdr.c
index 509f1da5..ec85fa71 100644
--- a/libelf/elf_getarhdr.c
+++ b/libelf/elf_getarhdr.c
@@ -44,30 +44,12 @@ elf_getarhdr (Elf *elf)
if (elf == NULL)
return NULL;
- Elf *parent = elf->parent;
-
/* Calling this function is not ok for any file type but archives. */
- if (parent == NULL)
+ if (elf->parent == NULL)
{
__libelf_seterrno (ELF_E_INVALID_OP);
return NULL;
}
- /* Make sure we have read the archive header. */
- if (parent->state.ar.elf_ar_hdr.ar_name == NULL
- && __libelf_next_arhdr_wrlock (parent) != 0)
-{
- rwlock_wrlock (parent->lock);
- int st = __libelf_next_arhdr_wrlock (parent);
- rwlock_unlock (parent->lock);
-
- if (st != 0)
- /* Something went wrong. Maybe there is no member left. */
- return NULL;
-}
-
- /* We can be sure the parent is an archive. */
- assert (parent->kind == ELF_K_AR);
-
- return &parent->state.ar.elf_ar_hdr;
+ return &elf->elf_ar_hdr;
}
diff --git a/libelf/libelfP.h b/libelf/libelfP.h
index 66e7e4dd..20120ad3 100644
--- a/libelf/libelfP.h
+++ b/libelf/libelfP.h
@@ -306,6 +306,9 @@ struct Elf
/* Reference counting for the descriptor. */
int ref_count;
+ /* Per-descriptor copy of the structure returned by 'elf_getarhdr'. */
+ Elf_Arhdr elf_ar_hdr;
+
/* Lock to handle multithreaded programs. */
rwlock_define (,lock);
diff --git a/tests/arextract.c b/tests/arextract.c
index 936d7f55..7920d1c9 100644
--- a/tests/arextract.c
+++ b/tests/arextract.c
@@ -21,12 +21,20 @@
#include
#include
+#include
#include
#include
#include
#include
#include
+typedef struct hdr_node {
+Elf *elf;
+Elf_Arhdr *hdr;
+struct hdr_node *next;
+} hdr_node;
+
+hdr_node *hdr_list = NULL;
int
main (int argc, char *argv[])
@@ -80,6 +88,27 @@ main (int argc, char *argv[])
exit (1);
}
+/* Keep a list of subelfs and their Elf_Arhdr. This is used to
+ verifiy that each archive member descriptor stores its own
+ Elf_Ahdr as opposed to the archive descriptor storing one
+ Elf_Ahdr at a time for all archive members. */
+hdr_node *node = calloc (1, sizeof (hdr_node));
+if (node == NULL)
+ {
+printf ("calloc failed: %s\n", strerror (errno));
+exit (1);
+ }
+node->elf = subelf;
+node->hdr = arhdr;
+
+if (hdr_list != NULL)
+ {
+ node->next = hdr_list;
+hdr_list = node;
+ }
+ else
+ hdr_list = node;
+
if (strcmp (arhdr->ar_name
[PATCH 5/7 v3] doc: Add elf_getarhdr.3
Signed-off-by: Aaron Merey
---
v3: Remove mention of elf_rand and elf_next invalidating Elf_Arhdr.
Change thread safety attribute to MT-safe.
doc/Makefile.am| 1 +
doc/elf_getarhdr.3 | 78 ++
2 files changed, 79 insertions(+)
create mode 100644 doc/elf_getarhdr.3
diff --git a/doc/Makefile.am b/doc/Makefile.am
index 6451ffab..aae29ebc 100644
--- a/doc/Makefile.am
+++ b/doc/Makefile.am
@@ -55,6 +55,7 @@ notrans_dist_man3_MANS= elf32_checksum.3 \
elf_errmsg.3 \
elf_errno.3 \
elf_fill.3 \
+ elf_getarhdr.3 \
elf_getaroff.3 \
elf_getbase.3 \
elf_getdata.3 \
diff --git a/doc/elf_getarhdr.3 b/doc/elf_getarhdr.3
new file mode 100644
index ..6ad90c69
--- /dev/null
+++ b/doc/elf_getarhdr.3
@@ -0,0 +1,78 @@
+.TH ELF_GETARHDR 3 2025-06-06 "Libelf" "Libelf Programmer's Manual"
+
+.SH NAME
+elf_getarhdr \- retrieve archive member header information
+
+.SH SYNOPSIS
+.nf
+.B #include
+
+.BI "Elf_Arhdr *elf_getarhdr(Elf *" elf ");"
+.fi
+
+.SH DESCRIPTION
+Return a
+.B Elf_Arhdr *
+describing the archive header of the archive member currently referred
+to by an ELF descriptor.
+
+The
+.B Elf_Arhdr
+structure is defined as:
+
+.P
+.nf
+typedef struct {
+ char *ar_name;/* Name of archive member. */
+ time_t ar_date; /* File date. */
+ uid_t ar_uid; /* User ID. */
+ gid_t ar_gid; /* Group ID. */
+ mode_t ar_mode; /* File mode. */
+ int64_t ar_size; /* File size. */
+ char *ar_rawname; /* Original name of archive member. */
+} Elf_Arhdr;
+.fi
+
+.SH PARAMETERS
+.TP
+.I elf
+An ELF descriptor referring to a member of an archive file.
+
+.SH RETURN VALUE
+If
+.I elf
+refers to an archive member,
+.B elf_getarhdr()
+returns a pointer to its archive header.
+This pointer is valid until
+.I elf
+or the parent archive Elf descriptor are closed using
+.BR elf_end() .
+If
+.I elf
+does not refer to an archive member or the header cannot be
+acquired then NULL is returned.
+
+.SH SEE ALSO
+.BR elf_begin (3),
+.BR elf_getaroff (3),
+.BR elf_next (3),
+.BR elf_rand (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_getarhdr ()
+T} Thread safety MT-safe
+.TE
+
+.SH REPORTING BUGS
+Report bugs to or
https://sourceware.org/bugzilla/.
--
2.50.0
[PATCH 4/7 v3] doc: Add elf_getaroff.3
Signed-off-by: Aaron Merey
---
v3 changes:
Update return value description to reflect that elf_getaroff returns
-1 if there's an error, not ELF_C_NULL (0).
doc/Makefile.am| 1 +
doc/elf_getaroff.3 | 58 ++
2 files changed, 59 insertions(+)
create mode 100644 doc/elf_getaroff.3
diff --git a/doc/Makefile.am b/doc/Makefile.am
index fbfebfe0..6451ffab 100644
--- a/doc/Makefile.am
+++ b/doc/Makefile.am
@@ -55,6 +55,7 @@ notrans_dist_man3_MANS= elf32_checksum.3 \
elf_errmsg.3 \
elf_errno.3 \
elf_fill.3 \
+ elf_getaroff.3 \
elf_getbase.3 \
elf_getdata.3 \
elf_getscn.3 \
diff --git a/doc/elf_getaroff.3 b/doc/elf_getaroff.3
new file mode 100644
index ..75f40795
--- /dev/null
+++ b/doc/elf_getaroff.3
@@ -0,0 +1,58 @@
+.TH ELF_GETAROFF 3 2025-06-06 "Libelf" "Libelf Programmer's Manual"
+
+.SH NAME
+elf_getaroff \- retrieve the offset of an archive member header
+
+.SH SYNOPSIS
+.nf
+.B #include
+
+.BI "int64_t elf_getaroff(Elf *" elf ");"
+.fi
+.SH DESCRIPTION
+Return the file offset, in bytes, of the archive member header currently
+referred to by an ELF descriptor. This is the offset of the member header
+in the parent archive file. This offset can be used with
+.BR elf_rand .
+
+.SH PARAMETERS
+.TP
+.I elf
+Elf descriptor referring to a member of an archive file header.
+
+.SH RETURN VALUE
+Return the file offset, in bytes, of the archive member header referred
+to by
+.IR elf .
+If
+.I elf
+is NULL or is not a member of an archive,
+return -1.
+
+.SH SEE ALSO
+.BR elf_begin (3),
+.BR elf_next (3),
+.BR elf_rand (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_getaroff ()
+T} Thread safety MT-Safe
+.TE
+
+.SH REPORTING BUGS
+Report bugs to or
https://sourceware.org/bugzilla/.
+
+.SH HISTORY
+.B elf_getaroff
+first appeared in elfutils 0.114. This elfutils libelf function may not be
+found in other libelf implementations.
--
2.50.0
[PATCH 1/7] elf_getaroff: Fix elf_getaroff error return value
elf_getaroff currently returns ELF_C_NULL (0) to indicate that an error
occured (ex. the Elf descriptor is not associated with an archive).
However elf_getaroff is intended to return -1 if an error occurs.
eu-ar assumes -1 indicates an error and other libelf implementations
use -1 to indicate an error in elf_getaroff.
Replace ELF_C_NULL with -1 as elf_getaroff's error return value.
Signed-off-by: Aaron Merey
---
libelf/elf_getaroff.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/libelf/elf_getaroff.c b/libelf/elf_getaroff.c
index 5c102ad6..5737b350 100644
--- a/libelf/elf_getaroff.c
+++ b/libelf/elf_getaroff.c
@@ -43,7 +43,7 @@ elf_getaroff (Elf *elf)
{
/* Be gratious, the specs demand it. */
if (elf == NULL || elf->parent == NULL)
-return ELF_C_NULL;
+return -1;
/* We can be sure the parent is an archive. */
Elf *parent = elf->parent;
--
2.50.0
[PATCH 7/7 v3] doc: Add elf_compress.3 and elf_compress_gnu.3
Signed-off-by: Aaron Merey --- v3: Use the libelf.h comment for elf_compress/elf_compress_gnu as the DESCRIPTION. Do not include ELFCOMPRESS_LOOS, ELFCOMPRESS_LOPROC, etc. as valid compression algorithm types. Mention that OS and arch-specific algorithm types aren't supported. doc/Makefile.am| 2 + doc/elf_compress.3 | 226 + doc/elf_compress_gnu.3 | 1 + 3 files changed, 229 insertions(+) create mode 100644 doc/elf_compress.3 create mode 100644 doc/elf_compress_gnu.3 diff --git a/doc/Makefile.am b/doc/Makefile.am index 486d9f22..9047a3ae 100644 --- a/doc/Makefile.am +++ b/doc/Makefile.am @@ -52,6 +52,8 @@ notrans_dist_man3_MANS= elf32_checksum.3 \ elf_begin.3 \ elf_clone.3 \ elf_cntl.3 \ + elf_compress.3 \ + elf_compress_gnu.3 \ elf_end.3 \ elf_errmsg.3 \ elf_errno.3 \ diff --git a/doc/elf_compress.3 b/doc/elf_compress.3 new file mode 100644 index ..e1d584ad --- /dev/null +++ b/doc/elf_compress.3 @@ -0,0 +1,226 @@ +.TH ELF_COMPRESS 3 2025-06-09 "Libelf" "Libelf Programmer's Manual" + +.SH NAME +elf_compress, elf_compress_gnu \- compress or decompress a section in an ELF object +.SH SYNOPSIS +.nf +#include + +.BI "int elf_compress (Elf_Scn *" scn ", int" type ", unsigned int "flags"); +.BI "int elf_compress_gnu (Elf_Scn *" scn ", int" compress ", unsigned int" flags "); +.fi + +.SH DESCRIPTION +.PP +.B elf_compress +works by setting or clearing the +.B SHF_COMPRESS +flag from the section +.I Shdr +and will encode or decode a +.I Elf32_Chdr +or +.I Elf64_Chdr +at the start of the section data. +.B elf_compress_gnu +will encode or decode any section, but is traditionally only used for +sections that have a name starting with +.B ".debug" +when uncompressed or +.B ".zdebug" +when compressed and stores just the uncompressed size. +The GNU compression method is deprecated and should only be used for +legacy support. + +.B elf_compress +takes a compression type that should be either zero to decompress or an +.B ELFCOMPRESS +algorithm to use for compression. +Currently +.B ELFCOMPRESS_ZLIB +and +.B ELFCOMPRESS_ZSTD +are supported. +.B elf_compress_gnu +will compress in the traditional GNU compression format when +.I compress +is one and decompress the section data when +.I compress +is zero. + +The +.I FLAGS +argument can be zero or +.B ELF_CHF_FORCE. +If +.I FLAGS +contains +.B ELF_CHF_FORCE +then it will always compress the section, even if that would not reduce +the size of the data section (including the header). Otherwise +.B elf_compress +and +.B elf_compress_gnu +will compress the section only if the total data size is reduced. +.PP +On successful compression or decompression the function returns one. +If (not forced) compression is requested and the data section would not +actually reduce in size, the section is not actually compressed and zero +is returned. Otherwise +.B \-1 +is returned and +.B elf_errno +is set. +.PP +It is an error to request compression for a section that already has +.B SHF_COMPRESSED +set, or (for +.BR elf_compress ) +to request decompression for an section that doesn't have +.B SHF_COMPRESSED +set. +If a section has +.B SHF_COMPRESSED +set then calling +.B elf_compress_gnu +will result in an error. +The section has to be decompressed first using +.B elf_compress. +Calling +.B elf_compress +on a section compressed with +.B elf_compress_gnu +is fine, but probably useless. +.PP +It is always an error to call these functions on +.B SHT_NOBITS +sections or if the section has the +.B SHF_ALLOC +flag set. +.B elf_compress_gnu +will not check whether the section name starts with +.B ".debug" +or +.B ".zdebug". +It is the responsibility of the caller to make sure the deprecated GNU +compression method is only called on correctly named sections (and to +change the name of the section when using +.BR elf_compress_gnu ). +.PP +All previous returned +.I Shdr +and +.I Elf_Data +buffers are invalidated by this call and should no longer be accessed. +.PP +Note that although this changes the header and data returned it doesn't +mark the section as dirty. To keep the changes when calling +.B elf_update +the section has to be flagged +.B ELF_F_DIRTY. + +.SH PARAMETERS +.SS elf_compress +.TP +.I scn +A pointer to an +.B Elf_Scn +structure representing the section to compress or decompress. Must not +be NULL. The section must not be of type +.B SHT_NOBITS +and must not have the +.B SHF_ALLOC +flag set. + +.TP +.I type +Specifies the compression algorithm or decompression mode. Elfutils +libelf does not support OS and processor specific compression algorithms. +Valid values are: +.RS +.TP +.B 0 +Decompress the section. The section must currently have the +.B SHF_COMPRESSED +flag set. +.TP +.B ELFCOMPRESS_ZLIB +Compress the section using the Z
