Dmitry V. Levin
b5d25ec2f9
* lseek.c: New file. * Makefile.am (strace_SOURCES): Add it. * file.c: Move sys_lseek, sys_llseek, and related code to lseek.c.
89 lines
2.3 KiB
C
89 lines
2.3 KiB
C
#include "defs.h"
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#include "xlat/whence_codes.h"
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/* Linux kernel has exactly one version of lseek:
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* fs/read_write.c::SYSCALL_DEFINE3(lseek, unsigned, fd, off_t, offset, unsigned, origin)
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* In kernel, off_t is always the same as (kernel's) long
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* (see include/uapi/asm-generic/posix_types.h),
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* which means that on x32 we need to use tcp->ext_arg[N] to get offset argument.
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* Use test/x32_lseek.c to test lseek decoding.
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*/
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#if defined(LINUX_MIPSN32) || defined(X32)
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int
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sys_lseek(struct tcb *tcp)
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{
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long long offset;
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int whence;
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if (entering(tcp)) {
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printfd(tcp, tcp->u_arg[0]);
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offset = tcp->ext_arg[1];
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whence = tcp->u_arg[2];
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if (whence == SEEK_SET)
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tprintf(", %llu, ", offset);
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else
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tprintf(", %lld, ", offset);
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printxval(whence_codes, whence, "SEEK_???");
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}
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return RVAL_LUDECIMAL;
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}
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#else
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int
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sys_lseek(struct tcb *tcp)
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{
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long offset;
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int whence;
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if (entering(tcp)) {
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printfd(tcp, tcp->u_arg[0]);
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offset = tcp->u_arg[1];
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whence = tcp->u_arg[2];
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if (whence == SEEK_SET)
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tprintf(", %lu, ", offset);
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else
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tprintf(", %ld, ", offset);
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printxval(whence_codes, whence, "SEEK_???");
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}
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return RVAL_UDECIMAL;
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}
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#endif
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/* llseek syscall takes explicitly two ulong arguments hi, lo,
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* rather than one 64-bit argument for which LONG_LONG works
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* appropriate for the native byte order.
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*
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* See kernel's fs/read_write.c::SYSCALL_DEFINE5(llseek, ...)
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*
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* hi,lo are "unsigned longs" and combined exactly this way in kernel:
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* ((loff_t) hi << 32) | lo
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* Note that for architectures with kernel's long wider than userspace long
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* (such as x32), combining code will use *kernel's*, i.e. *wide* longs
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* for hi and lo. We would need to use tcp->ext_arg[N] on x32...
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* ...however, x32 (and x86_64) does not _have_ llseek syscall as such.
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*/
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int
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sys_llseek(struct tcb *tcp)
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{
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if (entering(tcp)) {
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printfd(tcp, tcp->u_arg[0]);
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if (tcp->u_arg[4] == SEEK_SET)
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tprintf(", %llu, ",
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((long long) tcp->u_arg[1]) << 32 |
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(unsigned long long) (unsigned) tcp->u_arg[2]);
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else
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tprintf(", %lld, ",
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((long long) tcp->u_arg[1]) << 32 |
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(unsigned long long) (unsigned) tcp->u_arg[2]);
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}
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else {
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long long off;
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if (syserror(tcp) || umove(tcp, tcp->u_arg[3], &off) < 0)
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tprintf("%#lx, ", tcp->u_arg[3]);
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else
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tprintf("[%llu], ", off);
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printxval(whence_codes, tcp->u_arg[4], "SEEK_???");
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}
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return 0;
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}
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