From 5f9f31ad129d97e6fc548954c9b97e27dd332600 Mon Sep 17 00:00:00 2001 From: Adhemerval Zanella Date: Mon, 18 Sep 2017 09:26:00 -0300 Subject: scratch_buffer: use union for internal buffer Problem reported by Florian Weimer [1] and solution suggested by Andreas Schwab [2]. It also set the same buffer size independent of architecture max_align_t size. Checked on x86_64-linux-gnu and i686-linux-gnu. * lib/malloc/scratch_buffer.h (struct scratch_buffer): Use an union instead of a max_align_t array for __space, so that __space is the same size on all platforms. * malloc/scratch_buffer_grow_preserve.c (__libc_scratch_buffer_grow_preserve): Likewise. [1] https://sourceware.org/ml/libc-alpha/2017-09/msg00693.html [2] https://sourceware.org/ml/libc-alpha/2017-09/msg00695.html --- include/scratch_buffer.h | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'include/scratch_buffer.h') diff --git a/include/scratch_buffer.h b/include/scratch_buffer.h index bb04662eb2..b19b166080 100644 --- a/include/scratch_buffer.h +++ b/include/scratch_buffer.h @@ -66,7 +66,7 @@ struct scratch_buffer { void *data; /* Pointer to the beginning of the scratch area. */ size_t length; /* Allocated space at the data pointer, in bytes. */ - max_align_t __space[(1023 + sizeof (max_align_t)) / sizeof (max_align_t)]; + union { max_align_t __align; char __c[1024]; } __space; }; /* Initializes *BUFFER so that BUFFER->data points to BUFFER->__space @@ -74,7 +74,7 @@ struct scratch_buffer { static inline void scratch_buffer_init (struct scratch_buffer *buffer) { - buffer->data = buffer->__space; + buffer->data = buffer->__space.__c; buffer->length = sizeof (buffer->__space); } @@ -82,7 +82,7 @@ scratch_buffer_init (struct scratch_buffer *buffer) static inline void scratch_buffer_free (struct scratch_buffer *buffer) { - if (buffer->data != buffer->__space) + if (buffer->data != buffer->__space.__c) free (buffer->data); } -- cgit v1.2.3