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unifdef: use memcpy instead of strncpy

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New versions of gcc reasonably warn about the odd pattern of

	strncpy(p, q, strlen(q));

which really doesn't make sense: the strncpy() ends up being just a slow
and odd way to write memcpy() in this case.

There was a comment about _why_ the code used strncpy - to avoid the
terminating NUL byte, but memcpy does the same and avoids the warning.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Linus Torvalds 2018-11-30 14:45:01 -08:00
parent b6839ef26e
commit 38c7b224ce
1 changed files with 2 additions and 2 deletions
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4
scripts/unifdef.c
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@ -395,7 +395,7 @@ usage(void)
* When we have processed a group that starts off with a known-false
* #if/#elif sequence (which has therefore been deleted) followed by a
* #elif that we don't understand and therefore must keep, we edit the
* latter into a #if to keep the nesting correct. We use strncpy() to
* latter into a #if to keep the nesting correct. We use memcpy() to
* overwrite the 4 byte token "elif" with "if " without a '\0' byte.
*
* When we find a true #elif in a group, the following block will
@ -450,7 +450,7 @@ static void Idrop (void) { Fdrop(); ignoreon(); }
static void Itrue (void) { Ftrue(); ignoreon(); }
static void Ifalse(void) { Ffalse(); ignoreon(); }
/* modify this line */
static void Mpass (void) { strncpy(keyword, "if ", 4); Pelif(); }
static void Mpass (void) { memcpy(keyword, "if ", 4); Pelif(); }
static void Mtrue (void) { keywordedit("else"); state(IS_TRUE_MIDDLE); }
static void Melif (void) { keywordedit("endif"); state(IS_FALSE_TRAILER); }
static void Melse (void) { keywordedit("endif"); state(IS_FALSE_ELSE); }