| Dmitry V. Levin | b5d25ec | 2014-12-06 03:53:16 +0000 | [diff] [blame] | 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) |
| 13 | int |
| 14 | sys_lseek(struct tcb *tcp) |
| 15 | { |
| 16 | long long offset; |
| 17 | int whence; |
| 18 | |
| 19 | if (entering(tcp)) { |
| 20 | printfd(tcp, tcp->u_arg[0]); |
| 21 | offset = tcp->ext_arg[1]; |
| 22 | whence = tcp->u_arg[2]; |
| 23 | if (whence == SEEK_SET) |
| 24 | tprintf(", %llu, ", offset); |
| 25 | else |
| 26 | tprintf(", %lld, ", offset); |
| 27 | printxval(whence_codes, whence, "SEEK_???"); |
| 28 | } |
| 29 | return RVAL_LUDECIMAL; |
| 30 | } |
| 31 | #else |
| 32 | int |
| 33 | sys_lseek(struct tcb *tcp) |
| 34 | { |
| 35 | long offset; |
| 36 | int whence; |
| 37 | |
| 38 | if (entering(tcp)) { |
| 39 | printfd(tcp, tcp->u_arg[0]); |
| 40 | offset = tcp->u_arg[1]; |
| 41 | whence = tcp->u_arg[2]; |
| 42 | if (whence == SEEK_SET) |
| 43 | tprintf(", %lu, ", offset); |
| 44 | else |
| 45 | tprintf(", %ld, ", offset); |
| 46 | printxval(whence_codes, whence, "SEEK_???"); |
| 47 | } |
| 48 | return RVAL_UDECIMAL; |
| 49 | } |
| 50 | #endif |
| 51 | |
| 52 | /* llseek syscall takes explicitly two ulong arguments hi, lo, |
| 53 | * rather than one 64-bit argument for which LONG_LONG works |
| 54 | * appropriate for the native byte order. |
| 55 | * |
| 56 | * See kernel's fs/read_write.c::SYSCALL_DEFINE5(llseek, ...) |
| 57 | * |
| 58 | * hi,lo are "unsigned longs" and combined exactly this way in kernel: |
| 59 | * ((loff_t) hi << 32) | lo |
| 60 | * Note that for architectures with kernel's long wider than userspace long |
| 61 | * (such as x32), combining code will use *kernel's*, i.e. *wide* longs |
| 62 | * for hi and lo. We would need to use tcp->ext_arg[N] on x32... |
| 63 | * ...however, x32 (and x86_64) does not _have_ llseek syscall as such. |
| 64 | */ |
| 65 | int |
| 66 | sys_llseek(struct tcb *tcp) |
| 67 | { |
| 68 | if (entering(tcp)) { |
| 69 | printfd(tcp, tcp->u_arg[0]); |
| 70 | if (tcp->u_arg[4] == SEEK_SET) |
| 71 | tprintf(", %llu, ", |
| 72 | ((long long) tcp->u_arg[1]) << 32 | |
| 73 | (unsigned long long) (unsigned) tcp->u_arg[2]); |
| 74 | else |
| 75 | tprintf(", %lld, ", |
| 76 | ((long long) tcp->u_arg[1]) << 32 | |
| 77 | (unsigned long long) (unsigned) tcp->u_arg[2]); |
| 78 | } |
| 79 | else { |
| 80 | long long off; |
| 81 | if (syserror(tcp) || umove(tcp, tcp->u_arg[3], &off) < 0) |
| 82 | tprintf("%#lx, ", tcp->u_arg[3]); |
| 83 | else |
| 84 | tprintf("[%llu], ", off); |
| 85 | printxval(whence_codes, tcp->u_arg[4], "SEEK_???"); |
| 86 | } |
| 87 | return 0; |
| 88 | } |