386 lines
11 KiB
C
386 lines
11 KiB
C
/* Process tracing interface `ptrace' for GNU Hurd.
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Copyright (C) 1991-2022 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<https://www.gnu.org/licenses/>. */
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#include <errno.h>
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#include <sys/ptrace.h>
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#include <sys/types.h>
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#include <stdarg.h>
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#include <hurd.h>
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#include <hurd/signal.h>
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#include <hurd/msg.h>
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#include <thread_state.h>
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/* Perform process tracing functions. REQUEST is one of the values
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in <sys/ptrace.h>, and determines the action to be taken.
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For all requests except PTRACE_TRACEME, PID specifies the process to be
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traced.
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PID and the other arguments described above for the various requests should
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appear (those that are used for the particular request) as:
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pid_t PID, void *ADDR, int DATA, void *ADDR2
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after PID. */
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int
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ptrace (enum __ptrace_request request, ... )
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{
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pid_t pid;
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void *addr, *addr2;
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natural_t data;
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va_list ap;
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/* Read data from PID's address space, from ADDR for DATA bytes. */
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error_t read_data (task_t task, vm_address_t *ourpage, vm_size_t *size)
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{
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/* Read the pages containing the addressed range. */
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error_t err;
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*size = round_page (addr + data) - trunc_page (addr);
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err = __vm_read (task, trunc_page (addr), *size, ourpage, size);
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return err;
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}
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/* Fetch the thread port for PID's user thread. */
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error_t fetch_user_thread (task_t task, thread_t *thread)
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{
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thread_t threadbuf[3], *threads = threadbuf;
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mach_msg_type_number_t nthreads = 3, i;
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error_t err = __task_threads (task, &threads, &nthreads);
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if (err)
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return err;
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if (nthreads == 0)
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return EINVAL;
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*thread = threads[0]; /* Assume user thread is first. */
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for (i = 1; i < nthreads; ++i)
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__mach_port_deallocate (__mach_task_self (), threads[i]);
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if (threads != threadbuf)
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__vm_deallocate (__mach_task_self (),
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(vm_address_t) threads, nthreads * sizeof threads[0]);
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return 0;
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}
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/* Fetch a thread state structure from PID and store it at ADDR. */
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int get_regs (int flavor, mach_msg_type_number_t count)
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{
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error_t err;
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task_t task = __pid2task (pid);
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thread_t thread;
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if (task == MACH_PORT_NULL)
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return -1;
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err = fetch_user_thread (task, &thread);
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__mach_port_deallocate (__mach_task_self (), task);
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if (!err)
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err = __thread_get_state (thread, flavor, addr, &count);
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__mach_port_deallocate (__mach_task_self (), thread);
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return err ? __hurd_fail (err) : 0;
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}
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switch (request)
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{
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case PTRACE_TRACEME:
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/* Make this process be traced. */
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__sigfillset (&_hurdsig_traced);
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__USEPORT (PROC, __proc_mark_traced (port));
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break;
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case PTRACE_CONT:
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va_start (ap, request);
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pid = va_arg (ap, pid_t);
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addr = va_arg (ap, void *);
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data = va_arg (ap, int);
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va_end (ap);
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{
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/* Send a DATA signal to PID, telling it to take the signal
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normally even if it's traced. */
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error_t err;
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task_t task = __pid2task (pid);
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if (task == MACH_PORT_NULL)
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return -1;
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if (data == SIGKILL)
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err = __task_terminate (task);
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else
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{
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if (addr != (void *) 1)
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{
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/* Move the user thread's PC to ADDR. */
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thread_t thread;
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err = fetch_user_thread (task, &thread);
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if (!err)
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{
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struct machine_thread_state state;
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mach_msg_type_number_t count = MACHINE_THREAD_STATE_COUNT;
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err = __thread_get_state (thread,
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MACHINE_THREAD_STATE_FLAVOR,
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(natural_t *) &state, &count);
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if (!err)
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{
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MACHINE_THREAD_STATE_SET_PC (&state, addr);
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err = __thread_set_state (thread,
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MACHINE_THREAD_STATE_FLAVOR,
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(natural_t *) &state, count);
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}
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}
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__mach_port_deallocate (__mach_task_self (), thread);
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}
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else
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err = 0;
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if (! err)
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/* Tell the process to take the signal (or just resume if 0). */
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err = HURD_MSGPORT_RPC
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(__USEPORT (PROC, __proc_getmsgport (port, pid, &msgport)),
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0, 0, __msg_sig_post_untraced (msgport, data, 0, task));
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}
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__mach_port_deallocate (__mach_task_self (), task);
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return err ? __hurd_fail (err) : 0;
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}
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case PTRACE_KILL:
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va_start (ap, request);
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pid = va_arg (ap, pid_t);
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va_end (ap);
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/* SIGKILL always just terminates the task,
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so normal kill is just the same when traced. */
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return __kill (pid, SIGKILL);
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case PTRACE_SINGLESTEP:
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/* This is a machine-dependent kernel RPC on
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machines that support it. Punt. */
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return __hurd_fail (EOPNOTSUPP);
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case PTRACE_ATTACH:
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case PTRACE_DETACH:
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va_start (ap, request);
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pid = va_arg (ap, pid_t);
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va_end (ap);
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{
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/* Tell PID to set or clear its trace bit. */
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error_t err;
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mach_port_t msgport;
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task_t task = __pid2task (pid);
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if (task == MACH_PORT_NULL)
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return -1;
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err = __USEPORT (PROC, __proc_getmsgport (port, pid, &msgport));
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if (! err)
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{
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err = __msg_set_init_int (msgport, task, INIT_TRACEMASK,
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request == PTRACE_DETACH ? 0
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: ~(sigset_t) 0);
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if (! err)
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{
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if (request == PTRACE_ATTACH)
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/* Now stop the process. */
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err = __msg_sig_post (msgport, SIGSTOP, 0, task);
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else
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/* Resume the process from tracing stop. */
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err = __msg_sig_post_untraced (msgport, 0, 0, task);
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}
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__mach_port_deallocate (__mach_task_self (), msgport);
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}
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__mach_port_deallocate (__mach_task_self (), task);
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return err ? __hurd_fail (err) : 0;
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}
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case PTRACE_PEEKTEXT:
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case PTRACE_PEEKDATA:
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va_start (ap, request);
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pid = va_arg (ap, pid_t);
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addr = va_arg (ap, void *);
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va_end (ap);
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{
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/* Read the page (or two pages, if the word lies on a boundary)
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containing the addressed word. */
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error_t err;
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vm_address_t ourpage;
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vm_size_t size;
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natural_t word;
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task_t task = __pid2task (pid);
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if (task == MACH_PORT_NULL)
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return -1;
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data = sizeof word;
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ourpage = 0;
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size = 0;
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err = read_data (task, &ourpage, &size);
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__mach_port_deallocate (__mach_task_self (), task);
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if (err)
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return __hurd_fail (err);
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word = *(natural_t *) ((vm_address_t) addr - trunc_page (addr)
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+ ourpage);
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__vm_deallocate (__mach_task_self (), ourpage, size);
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return word;
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}
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case PTRACE_PEEKUSER:
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case PTRACE_POKEUSER:
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/* U area, what's that? */
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return __hurd_fail (EOPNOTSUPP);
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case PTRACE_GETREGS:
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case PTRACE_SETREGS:
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va_start (ap, request);
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pid = va_arg (ap, pid_t);
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addr = va_arg (ap, void *);
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va_end (ap);
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return get_regs (MACHINE_THREAD_STATE_FLAVOR,
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MACHINE_THREAD_STATE_COUNT);
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case PTRACE_GETFPREGS:
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case PTRACE_SETFPREGS:
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va_start (ap, request);
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pid = va_arg (ap, pid_t);
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addr = va_arg (ap, void *);
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va_end (ap);
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#ifdef MACHINE_THREAD_FLOAT_STATE_FLAVOR
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return get_regs (MACHINE_THREAD_FLOAT_STATE_FLAVOR,
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MACHINE_THREAD_FLOAT_STATE_COUNT);
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#else
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return __hurd_fail (EOPNOTSUPP);
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#endif
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case PTRACE_GETFPAREGS:
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case PTRACE_SETFPAREGS:
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va_start (ap, request);
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pid = va_arg (ap, pid_t);
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addr = va_arg (ap, void *);
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va_end (ap);
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#ifdef MACHINE_THREAD_FPA_STATE_FLAVOR
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return get_regs (MACHINE_THREAD_FPA_STATE_FLAVOR,
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MACHINE_THREAD_FPA_STATE_COUNT);
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#else
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return __hurd_fail (EOPNOTSUPP);
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#endif
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case PTRACE_POKETEXT:
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case PTRACE_POKEDATA:
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va_start (ap, request);
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pid = va_arg (ap, pid_t);
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addr = va_arg (ap, void *);
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data = va_arg (ap, int);
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va_end (ap);
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{
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/* Read the page (or two pages, if the word lies on a boundary)
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containing the addressed word. */
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error_t err;
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vm_address_t ourpage;
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vm_size_t size;
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task_t task = __pid2task (pid);
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if (task == MACH_PORT_NULL)
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return -1;
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data = sizeof (natural_t);
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ourpage = 0;
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size = 0;
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err = read_data (task, &ourpage, &size);
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if (!err)
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{
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/* Now modify the specified word and write the page back. */
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*(natural_t *) ((vm_address_t) addr - trunc_page (addr)
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+ ourpage) = data;
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err = __vm_write (task, trunc_page (addr), ourpage, size);
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__vm_deallocate (__mach_task_self (), ourpage, size);
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}
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__mach_port_deallocate (__mach_task_self (), task);
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return err ? __hurd_fail (err) : 0;
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}
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case PTRACE_READDATA:
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case PTRACE_READTEXT:
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va_start (ap, request);
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pid = va_arg (ap, pid_t);
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addr = va_arg (ap, void *);
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data = va_arg (ap, int);
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addr2 = va_arg (ap, void *);
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va_end (ap);
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{
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error_t err;
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vm_address_t ourpage;
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vm_size_t size;
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task_t task = __pid2task (pid);
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if (task == MACH_PORT_NULL)
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return -1;
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if (((vm_address_t) addr2 + data) % __vm_page_size == 0)
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{
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/* Perhaps we can write directly to the user's buffer. */
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ourpage = (vm_address_t) addr2;
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size = data;
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}
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else
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{
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ourpage = 0;
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size = 0;
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}
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err = read_data (task, &ourpage, &size);
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__mach_port_deallocate (__mach_task_self (), task);
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if (!err && ourpage != (vm_address_t) addr2)
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{
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memcpy (addr2, (void *) ourpage, data);
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__vm_deallocate (__mach_task_self (), ourpage, size);
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}
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return err ? __hurd_fail (err) : 0;
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}
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case PTRACE_WRITEDATA:
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case PTRACE_WRITETEXT:
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va_start (ap, request);
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pid = va_arg (ap, pid_t);
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addr = va_arg (ap, void *);
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data = va_arg (ap, int);
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addr2 = va_arg (ap, void *);
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va_end (ap);
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{
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error_t err;
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vm_address_t ourpage;
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vm_size_t size;
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task_t task = __pid2task (pid);
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if (task == MACH_PORT_NULL)
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return -1;
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if ((vm_address_t) addr % __vm_page_size == 0
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&& (vm_address_t) data % __vm_page_size == 0)
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{
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/* Writing whole pages; can go directly from the user's buffer. */
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ourpage = (vm_address_t) addr2;
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size = data;
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err = 0;
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}
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else
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{
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/* Read the task's pages and modify our own copy. */
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ourpage = 0;
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size = 0;
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err = read_data (task, &ourpage, &size);
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if (!err)
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memcpy ((void *) ((vm_address_t) addr - trunc_page (addr)
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+ ourpage),
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addr2,
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data);
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}
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if (!err)
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/* Write back the modified pages. */
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err = __vm_write (task, trunc_page (addr), ourpage, size);
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__mach_port_deallocate (__mach_task_self (), task);
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return err ? __hurd_fail (err) : 0;
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}
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default:
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errno = EINVAL;
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return -1;
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}
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return 0;
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}
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