From 85563b7fc7ec2cd21e38debb9b28db342e2e8e7c Mon Sep 17 00:00:00 2001 From: Michael Biebl Date: Sun, 21 Apr 2019 21:09:51 +0200 Subject: New upstream version 1.18.0 --- shared/systemd/src/basic/memory-util.c | 59 ++++++++++++++++++++++++++++++++++ 1 file changed, 59 insertions(+) create mode 100644 shared/systemd/src/basic/memory-util.c (limited to 'shared/systemd/src/basic/memory-util.c') diff --git a/shared/systemd/src/basic/memory-util.c b/shared/systemd/src/basic/memory-util.c new file mode 100644 index 00000000..bd1f5d73 --- /dev/null +++ b/shared/systemd/src/basic/memory-util.c @@ -0,0 +1,59 @@ +#include "nm-sd-adapt-shared.h" + +#include + +#include "memory-util.h" + +size_t page_size(void) { + static thread_local size_t pgsz = 0; + long r; + + if (_likely_(pgsz > 0)) + return pgsz; + + r = sysconf(_SC_PAGESIZE); + assert(r > 0); + + pgsz = (size_t) r; + return pgsz; +} + +bool memeqzero(const void *data, size_t length) { + /* Does the buffer consist entirely of NULs? + * Copied from https://github.com/systemd/casync/, copied in turn from + * https://github.com/rustyrussell/ccan/blob/master/ccan/mem/mem.c#L92, + * which is licensed CC-0. + */ + + const uint8_t *p = data; + size_t i; + + /* Check first 16 bytes manually */ + for (i = 0; i < 16; i++, length--) { + if (length == 0) + return true; + if (p[i]) + return false; + } + + /* Now we know first 16 bytes are NUL, memcmp with self. */ + return memcmp(data, p + i, length) == 0; +} + +#if !HAVE_EXPLICIT_BZERO +/* + * The pointer to memset() is volatile so that compiler must de-reference the pointer and can't assume that + * it points to any function in particular (such as memset(), which it then might further "optimize"). This + * approach is inspired by openssl's crypto/mem_clr.c. + */ +typedef void *(*memset_t)(void *,int,size_t); + +static volatile memset_t memset_func = memset; + +void* explicit_bzero_safe(void *p, size_t l) { + if (l > 0) + memset_func(p, '\0', l); + + return p; +} +#endif -- cgit 1.3.0-6-gf8a5