1 /*
2 * Copyright (c) 2018 The strace developers.
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 3. The name of the author may not be used to endorse or promote products
14 * derived from this software without specific prior written permission.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
21 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
25 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26 */
27
28 #include "defs.h"
29
30 /*
31 * Fetch indirect syscall arguments that are provided as an array.
32 * Return a pointer to a static array of kernel_ulong_t elements,
33 * or NULL in case of fetch failure.
34 */
35 kernel_ulong_t *
fetch_indirect_syscall_args(struct tcb * const tcp,const kernel_ulong_t addr,const unsigned int n_args)36 fetch_indirect_syscall_args(struct tcb *const tcp,
37 const kernel_ulong_t addr,
38 const unsigned int n_args)
39 {
40 static kernel_ulong_t u_arg[MAX_ARGS];
41
42 if (current_wordsize == sizeof(*u_arg)) {
43 if (umoven(tcp, addr, sizeof(*u_arg) * n_args, u_arg))
44 return NULL;
45 } else {
46 uint32_t narrow_arg[ARRAY_SIZE(u_arg)];
47
48 if (umoven(tcp, addr, sizeof(*narrow_arg) * n_args, narrow_arg))
49 return NULL;
50 for (unsigned int i = 0; i < n_args; ++i)
51 u_arg[i] = narrow_arg[i];
52 }
53
54 return u_arg;
55 }
56