Commit 37ae2d59 authored Nov 23, 2011 by Arnaud Lacombe Committed by Michal Marek Jan 15, 2012

kbuild: Fix compiler warning with assertion when calling 'fwrite'



Reinhard Tartler discovered a corner case of calling xfwrite() where the
length of the string is zero.

Arnaud Lacombe suggested to use assertion for the corner case, as
fwrite(3) is currently used:

 1) in comment printers. Empty comment are not allowed.
 2) in a callback passed to expr_print(), where the string printed is
    either NULL OR non-empty.
 3) in the lexer, auto-generated, and unused.

I feel using assertion is a good solution:

 1) It cleanly takes care of the above-mentioned corner case.
 2) It can be easily disabled by defining NDEBUG.
 3) It asserts xfwrite() is simply a wrapper for fwrite().

Reported-by: Reinhard Tartler <Reinhard.Tartler@informatik.uni-erlangen.de>
Signed-off-by: Arnaud Lacombe <lacombar@gmail.com>
Signed-off-by: Jean Sacren <sakiwit@gmail.com>
Signed-off-by: Michal Marek <mmarek@suse.cz>

parent e2aef4d3

scripts/kconfig/expr.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -10,6 +10,7 @@
		extern "C" {
		#endif

		#include <assert.h>
		#include <stdio.h>
		#ifndef __cplusplus
		#include <stdbool.h>

scripts/kconfig/lkc.h

+4 −2

Original line number	Diff line number	Diff line
		@@ -90,8 +90,10 @@ struct conf_printer {
		/* confdata.c and expr.c */
		static inline void xfwrite(const void str, size_t len, size_t count, FILE out)
		{
		if (fwrite(str, len, count, out) < count)
		fprintf(stderr, "\nError in writing or end of file.\n");
		assert(len != 0);

		if (fwrite(str, len, count, out) != count)
		fprintf(stderr, "Error in writing or end of file.\n");
		}

		/* menu.c */

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