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Annotation of embedaddon/sudo/compat/memset_s.c, revision 1.1.1.1

1.1       misho       1: /*
                      2:  * Copyright (c) 2013 Todd C. Miller <Todd.Miller@courtesan.com>
                      3:  *
                      4:  * Permission to use, copy, modify, and distribute this software for any
                      5:  * purpose with or without fee is hereby granted, provided that the above
                      6:  * copyright notice and this permission notice appear in all copies.
                      7:  *
                      8:  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
                      9:  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
                     10:  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
                     11:  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
                     12:  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
                     13:  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
                     14:  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
                     15:  */
                     16: 
                     17: #include <config.h>
                     18: 
                     19: #include <sys/types.h>
                     20: #include <errno.h>
                     21: #include <limits.h>
                     22: #if defined(HAVE_STDINT_H)
                     23: # include <stdint.h>
                     24: #elif defined(HAVE_INTTYPES_H)
                     25: # include <inttypes.h>
                     26: #endif
                     27: 
                     28: #include "missing.h"
                     29: 
                     30: #ifndef RSIZE_MAX
                     31: # if defined(SIZE_MAX)
                     32: #  define RSIZE_MAX (SIZE_MAX >> 1)
                     33: # elif defined(__LP64__)
                     34: #  define RSIZE_MAX 0x7fffffffffffffffUL
                     35: # else
                     36: #  define RSIZE_MAX 0x7fffffffU
                     37: # endif
                     38: #endif
                     39: 
                     40: /*
                     41:  * Simple implementation of C11 memset_s() function.
                     42:  * We use a volatile pointer when updating the byte string.
                     43:  * Most compilers will avoid optimizing away access to a
                     44:  * volatile pointer, even if the pointer appears to be unused
                     45:  * after the call.
                     46:  *
                     47:  * Note that C11 does not specify the return value on error, only
                     48:  * that it be non-zero.  We use EINVAL for all errors.
                     49:  */
                     50: errno_t
                     51: memset_s(void *v, rsize_t smax, int c, rsize_t n)
                     52: {
                     53:     errno_t ret = 0;
                     54:     volatile unsigned char *s = v;
                     55: 
                     56:     /* Fatal runtime-constraint violations. */
                     57:     if (s == NULL || smax > RSIZE_MAX) {
                     58:        ret = errno = EINVAL;
                     59:        goto done;
                     60:     }
                     61:     /* Non-fatal runtime-constraint violation, n must not exceed smax. */
                     62:     if (n > smax) {
                     63:        n = smax;
                     64:        ret = errno = EINVAL;
                     65:     }
                     66:     /* Updating through a volatile pointer should not be optimized away. */
                     67:     while (n--)
                     68:        *s++ = (unsigned char)c;
                     69: done:
                     70:     return ret;
                     71: }