- Make sure to set an error code when trying to obtain a data descriptor for

  a section of type SHT_NULL.
- Update the man page to reflect the fact that elf_getdata() and
  elf_rawdata() may return with an error of ELF_E_SECTION.

PR:		bin/175491
Approved by:	emaste (co-mentor)
MFC after:	1 week

2 files changed, 24 insertions, 3 deletions

diff --git a/lib/libelf/elf_data.c b/lib/libelf/elf_data.c
index c34c4ad..d3bd390 100644
--- a/lib/libelf/elf_data.c
+++ b/lib/libelf/elf_data.c
@@ -78,8 +78,10 @@ elf_getdata(Elf_Scn *s, Elf_Data *d)
 		sh_align  = s->s_shdr.s_shdr64.sh_addralign;
 	}
 
-	if (sh_type == SHT_NULL)
+	if (sh_type == SHT_NULL) {
+		LIBELF_SET_ERROR(SECTION, 0);
 		return (NULL);
+	}
 
 	if ((elftype = _libelf_xlate_shtype(sh_type)) < ELF_T_FIRST ||
 	    elftype > ELF_T_LAST || (sh_type != SHT_NOBITS &&
@@ -219,8 +221,10 @@ elf_rawdata(Elf_Scn *s, Elf_Data *d)
 		sh_align  = s->s_shdr.s_shdr64.sh_addralign;
 	}
 
-	if (sh_type == SHT_NULL)
+	if (sh_type == SHT_NULL) {
+		LIBELF_SET_ERROR(SECTION, 0);
 		return (NULL);
+	}
 
 	if ((d = _libelf_allocate_data(s)) == NULL)
 		return (NULL);
diff --git a/lib/libelf/elf_getdata.3 b/lib/libelf/elf_getdata.3
index 97766d8..7961220 100644
--- a/lib/libelf/elf_getdata.3
+++ b/lib/libelf/elf_getdata.3
@@ -23,7 +23,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd January 26, 2011
+.Dd February 18, 2013
 .Dt ELF_GETDATA 3
 .Os
 .Sh NAME
@@ -186,6 +186,23 @@ was not associated with section descriptor
 .Ar scn .
 .It Bq Er ELF_E_RESOURCE
 An out of memory condition was detected.
+.It Bq Er ELF_E_SECTION
+Section
+.Ar scn
+had type
+.Dv SHT_NULL .
+.It Bq Er ELF_E_SECTION
+The type of the section
+.Ar scn
+was not recognized by the library.
+.It Bq Er ELF_E_SECTION
+The size of the section
+.Ar scn
+is not a multiple of the file size for its section type.
+.It Bq Er ELF_E_SECTION
+The file offset for section
+.Ar scn
+is incorrect.
 .El
 .Sh SEE ALSO
 .Xr elf 3 ,