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authorArnaud Lacombe <lacombar@gmail.com>2011-11-23 13:05:53 -0500
committerMichal Marek <mmarek@suse.cz>2012-01-15 00:17:18 +0100
commit37ae2d5998aa29d8bf52f124199a21341bc6d18d (patch)
tree95cb787bfcb7340caaa1f20513b3f22edef886aa
parente2aef4d33ac43ec45e4fc2903288030d7f464832 (diff)
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>
-rw-r--r--scripts/kconfig/expr.h1
-rw-r--r--scripts/kconfig/lkc.h6
2 files changed, 5 insertions, 2 deletions
diff --git a/scripts/kconfig/expr.h b/scripts/kconfig/expr.h
index 80fce57080c..d4ecce8bc3a 100644
--- a/scripts/kconfig/expr.h
+++ b/scripts/kconfig/expr.h
@@ -10,6 +10,7 @@
extern "C" {
#endif
+#include <assert.h>
#include <stdio.h>
#ifndef __cplusplus
#include <stdbool.h>
diff --git a/scripts/kconfig/lkc.h b/scripts/kconfig/lkc.h
index b633bdb9f3d..c18f2bd9c09 100644
--- a/scripts/kconfig/lkc.h
+++ b/scripts/kconfig/lkc.h
@@ -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 */