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| author | Rich Felker <dalias@aerifal.cx> | 2018-09-26 14:39:10 -0400 |
|---|---|---|
| committer | Rich Felker <dalias@aerifal.cx> | 2018-09-26 14:39:10 -0400 |
| commit | 4d0a82170a25464c39522d7190b9fe302045ddb2 (patch) | |
| tree | b3a469567ed3a995300c9751b824ef20b84f154d /src/string/strlen.c | |
| parent | 8cd738bbee3b4e60a99b71599c338bf444070f18 (diff) | |
| download | musl-4d0a82170a25464c39522d7190b9fe302045ddb2.tar.gz | |
fix aliasing-based undefined behavior in string functions
use the GNU C may_alias attribute if available, and fallback to naive
byte-by-byte loops if __GNUC__ is not defined.
this patch has been written to minimize changes so that history
remains reviewable; it does not attempt to bring the affected code
into a more consistent or elegant form.
Diffstat (limited to 'src/string/strlen.c')
| -rw-r--r-- | src/string/strlen.c | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/src/string/strlen.c b/src/string/strlen.c index 929ddcbc..309990f0 100644 --- a/src/string/strlen.c +++ b/src/string/strlen.c @@ -10,9 +10,13 @@ size_t strlen(const char *s) { const char *a = s; - const size_t *w; +#ifdef __GNUC__ + typedef size_t __attribute__((__may_alias__)) word; + const word *w; for (; (uintptr_t)s % ALIGN; s++) if (!*s) return s-a; for (w = (const void *)s; !HASZERO(*w); w++); - for (s = (const void *)w; *s; s++); + s = (const void *)w; +#endif + for (; *s; s++); return s-a; } |