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>
diff --git a/scripts/kconfig/expr.h b/scripts/kconfig/expr.h
index 80fce57..d4ecce8 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 b633bdb..c18f2bd 100644
--- a/scripts/kconfig/lkc.h
+++ b/scripts/kconfig/lkc.h
@@ -90,8 +90,10 @@
/* 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 */