1 #include "defs.h"
2
3 #include "xlat/whence_codes.h"
4
5 /* Linux kernel has exactly one version of lseek:
6 * fs/read_write.c::SYSCALL_DEFINE3(lseek, unsigned, fd, off_t, offset, unsigned, origin)
7 * In kernel, off_t is always the same as (kernel's) long
8 * (see include/uapi/asm-generic/posix_types.h),
9 * which means that on x32 we need to use tcp->ext_arg[N] to get offset argument.
10 * Use test/x32_lseek.c to test lseek decoding.
11 */
12 #if defined(LINUX_MIPSN32) || defined(X32)
SYS_FUNC(lseek)13 SYS_FUNC(lseek)
14 {
15 long long offset;
16 int whence;
17
18 if (entering(tcp)) {
19 printfd(tcp, tcp->u_arg[0]);
20 offset = tcp->ext_arg[1];
21 whence = tcp->u_arg[2];
22 if (whence == SEEK_SET)
23 tprintf(", %llu, ", offset);
24 else
25 tprintf(", %lld, ", offset);
26 printxval(whence_codes, whence, "SEEK_???");
27 }
28 return RVAL_LUDECIMAL;
29 }
30 #else
SYS_FUNC(lseek)31 SYS_FUNC(lseek)
32 {
33 long offset;
34 int whence;
35
36 if (entering(tcp)) {
37 printfd(tcp, tcp->u_arg[0]);
38 offset = tcp->u_arg[1];
39 whence = tcp->u_arg[2];
40 if (whence == SEEK_SET)
41 tprintf(", %lu, ", offset);
42 else
43 tprintf(", %ld, ", offset);
44 printxval(whence_codes, whence, "SEEK_???");
45 }
46 return RVAL_UDECIMAL;
47 }
48 #endif
49
50 /* llseek syscall takes explicitly two ulong arguments hi, lo,
51 * rather than one 64-bit argument for which LONG_LONG works
52 * appropriate for the native byte order.
53 *
54 * See kernel's fs/read_write.c::SYSCALL_DEFINE5(llseek, ...)
55 *
56 * hi,lo are "unsigned longs" and combined exactly this way in kernel:
57 * ((loff_t) hi << 32) | lo
58 * Note that for architectures with kernel's long wider than userspace long
59 * (such as x32), combining code will use *kernel's*, i.e. *wide* longs
60 * for hi and lo. We would need to use tcp->ext_arg[N] on x32...
61 * ...however, x32 (and x86_64) does not _have_ llseek syscall as such.
62 */
SYS_FUNC(llseek)63 SYS_FUNC(llseek)
64 {
65 if (entering(tcp)) {
66 printfd(tcp, tcp->u_arg[0]);
67 if (tcp->u_arg[4] == SEEK_SET)
68 tprintf(", %llu, ",
69 ((long long) tcp->u_arg[1]) << 32 |
70 (unsigned long long) (unsigned) tcp->u_arg[2]);
71 else
72 tprintf(", %lld, ",
73 ((long long) tcp->u_arg[1]) << 32 |
74 (unsigned long long) (unsigned) tcp->u_arg[2]);
75 }
76 else {
77 long long off;
78 if (syserror(tcp) || umove(tcp, tcp->u_arg[3], &off) < 0)
79 tprintf("%#lx, ", tcp->u_arg[3]);
80 else
81 tprintf("[%llu], ", off);
82 printxval(whence_codes, tcp->u_arg[4], "SEEK_???");
83 }
84 return 0;
85 }
86