warn unused result for bfd IO functions

This patch fixes all the warnings I found in bfd, binutils and ld,
plus some bitrotted COFF_GO32 code that tried to allocate -168ul
bytes.  When the malloc fail was reported these testsuite fails
resulted:

i386-go32  +FAIL: go32 stub
i386-go32  +ERROR: tcl error sourcing /home/alan/src/binutils-gdb/ld/testsuite/ld-i386/i386.exp.
i386-go32  +ERROR: couldn't open "tmpdir/go32stub": no such file or directory
i386-go32  +FAIL: ld-scripts/sane1
i386-go32  +FAIL: ld-scripts/assign-loc
i386-go32  +FAIL: ld-scripts/pr18963

This does result in some warnings in gdb which are fixed in a followup
patch.

bfd/
	* bfdio.c (bfd_read, bfd_write): Add ATTRIBUTE_WARN_UNUSED_RESULT.
	(bfd_tell, bfd_stat, bfd_seek, bfd_mmap): Likewise.
	* bfd-in2.h: Regenerate.
	* coff-rs6000.c (xcoff_write_armap_big) Don't ignore bfd_write
	return value.
	(xcoff_generate_rtinit): Likewise.  Also free data_buffer and
	string_table before returning.
	* coff64-rs6000.c (xcoff64_generate_rtinit): Likewise.
	* coff-stgo32.c (go32exe_check_format): Don't ignore bfd_seek
	return value.
	* coffcode.h (coff_apply_checksum): Don't ignore bfd_write return.
	(coff_write_object_contents <COFF_GO32>): Likewise, and bfd_malloc.
	Fix bitrotted code to look for first section with non-zero filepos.
	* elf64-ia64-vms.c (elf64_vms_write_shdrs_and_ehdr): Don't ignore
	bfd_seek or bfd_write return values.
	* pef.c (bfd_pef_scan_section): Likewise.
	(bfd_pef_read_header, bfd_pef_xlib_read_header): Likewise.
	* vms-misc.c (_bfd_vms_output_end): Likewise.  Return status.
	* vms.h (_bfd_vms_output_end): Update prototype.
	* vms-alpha.c: Pass _bfd_vms_output_end status up call chains.
	* wasm-module.c (wasm_compute_custom_section_file_position): Don't
	ignore bfd_seek or bfd_write return values.
	(wasm_compute_section_file_positions): Likewise.
	* xsym.c (bfd_sym_scan): Don't ignore bfd_seek return value.
	(bfd_sym_read_name_table): Likewise.
binutils/
	* ar.c (print_contents, extract_file): Don't ignore bfd_seek
	return value.
ld/
	* pdb.c (create_section_contrib_substream): Don't ignore bfd_seek
	return value.
	(create_section_header_stream): Likewise.
	* pe-dll.c (pe_get16, pe_get32): Add fail param to return results
	from bfd_seek and bfd_read.
	(pe_implied_import_dll): Handle these fails, and other bfd_seek
	and bfd_read return values.

1 files changed, 29 insertions, 15 deletions

diff --git a/bfd/coff-rs6000.c b/bfd/coff-rs6000.c
index 06d0fd8..7dd80a5 100644
--- a/bfd/coff-rs6000.c
+++ b/bfd/coff-rs6000.c
@@ -2193,8 +2193,12 @@ xcoff_write_armap_big (bfd *abfd, unsigned int elength ATTRIBUTE_UNUSED,
 	    }
 	}
 
-      bfd_write (symbol_table, symbol_table_size, abfd);
-
+      if (bfd_write (symbol_table, symbol_table_size, abfd)
+	  != symbol_table_size)
+	{
+	  free (symbol_table);
+	  return false;
+	}
       free (symbol_table);
 
       prevoff = nextoff;
@@ -2273,8 +2277,12 @@ xcoff_write_armap_big (bfd *abfd, unsigned int elength ATTRIBUTE_UNUSED,
 	    }
 	}
 
-      bfd_write (symbol_table, symbol_table_size, abfd);
-
+      if (bfd_write (symbol_table, symbol_table_size, abfd)
+	  != symbol_table_size)
+	{
+	  free (symbol_table);
+	  return false;
+	}
       free (symbol_table);
 
       PRINT20 (fhdr->symoff64, nextoff);
@@ -4204,7 +4212,10 @@ xcoff_generate_rtinit  (bfd *abfd, const char *init, const char *fini,
       string_table_size += 4;
       string_table = (bfd_byte *) bfd_zmalloc (string_table_size);
       if (string_table == NULL)
-	return false;
+	{
+	  free (data_buffer);
+	  return false;
+	}
 
       val = string_table_size;
       bfd_h_put_32 (abfd, val, &string_table[0]);
@@ -4354,18 +4365,21 @@ xcoff_generate_rtinit  (bfd *abfd, const char *init, const char *fini,
   filehdr.f_symptr = scnhdr.s_relptr + scnhdr.s_nreloc * RELSZ;
 
   bfd_coff_swap_filehdr_out (abfd, &filehdr, filehdr_ext);
-  bfd_write (filehdr_ext, FILHSZ, abfd);
   bfd_coff_swap_scnhdr_out (abfd, &scnhdr, scnhdr_ext);
-  bfd_write (scnhdr_ext, SCNHSZ, abfd);
-  bfd_write (data_buffer, data_buffer_size, abfd);
-  bfd_write (reloc_ext, scnhdr.s_nreloc * RELSZ, abfd);
-  bfd_write (syment_ext, filehdr.f_nsyms * SYMESZ, abfd);
-  bfd_write (string_table, string_table_size, abfd);
-
+  bool ret = true;
+  if (bfd_write (filehdr_ext, FILHSZ, abfd) != FILHSZ
+      || bfd_write (scnhdr_ext, SCNHSZ, abfd) != SCNHSZ
+      || bfd_write (data_buffer, data_buffer_size, abfd) != data_buffer_size
+      || (bfd_write (reloc_ext, scnhdr.s_nreloc * RELSZ, abfd)
+	  != scnhdr.s_nreloc * RELSZ)
+      || (bfd_write (syment_ext, filehdr.f_nsyms * SYMESZ, abfd)
+	  != (bfd_size_type) filehdr.f_nsyms * SYMESZ)
+      || bfd_write (string_table, string_table_size, abfd) != string_table_size)
+    ret = false;
+
+  free (string_table);
   free (data_buffer);
-  data_buffer = NULL;
-
-  return true;
+  return ret;
 }