275 lines
8.1 KiB
C
275 lines
8.1 KiB
C
/* This file handles the process manager's part of debugging, using the
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* ptrace system call. Most of the commands are passed on to the system
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* task for completion.
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*
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* The debugging commands available are:
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* T_STOP stop the process
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* T_OK enable tracing by parent for this process
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* T_GETINS return value from instruction space
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* T_GETDATA return value from data space
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* T_GETUSER return value from user process table
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* T_SETINS set value in instruction space
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* T_SETDATA set value in data space
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* T_SETUSER set value in user process table
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* T_RESUME resume execution
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* T_EXIT exit
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* T_STEP set trace bit
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* T_SYSCALL trace system call
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* T_ATTACH attach to an existing process
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* T_DETACH detach from a traced process
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* T_SETOPT set trace options
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* T_GETRANGE get range of values
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* T_SETRANGE set range of values
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*
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* The T_OK, T_ATTACH, T_EXIT, and T_SETOPT commands are handled here, and the
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* T_RESUME, T_STEP, T_SYSCALL, and T_DETACH commands are partially handled
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* here and completed by the system task. The rest are handled entirely by the
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* system task.
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*/
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#include "pm.h"
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#include <minix/com.h>
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#include <minix/callnr.h>
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#include <sys/ptrace.h>
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#include <sys/wait.h>
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#include <signal.h>
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#include "mproc.h"
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/*===========================================================================*
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* do_trace *
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*===========================================================================*/
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int do_trace()
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{
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register struct mproc *child;
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struct ptrace_range pr;
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int i, r, req;
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req = m_in.m_lc_pm_ptrace.req;
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/* The T_OK call is made by the child fork of the debugger before it execs
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* the process to be traced. The T_ATTACH call is made by the debugger itself
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* to attach to an existing process.
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*/
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switch (req) {
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case T_OK: /* enable tracing by parent for this proc */
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if (mp->mp_tracer != NO_TRACER) return(EBUSY);
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mp->mp_tracer = mp->mp_parent;
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mp->mp_reply.m_pm_lc_ptrace.data = 0;
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return(OK);
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case T_ATTACH: /* attach to an existing process */
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if ((child = find_proc(m_in.m_lc_pm_ptrace.pid)) == NULL) return(ESRCH);
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if (child->mp_flags & EXITING) return(ESRCH);
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/* For non-root processes, user and group ID must match. */
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if (mp->mp_effuid != SUPER_USER &&
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(mp->mp_effuid != child->mp_effuid ||
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mp->mp_effgid != child->mp_effgid ||
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child->mp_effuid != child->mp_realuid ||
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child->mp_effgid != child->mp_realgid)) return(EPERM);
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/* Only root may trace system servers. */
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if (mp->mp_effuid != SUPER_USER && (child->mp_flags & PRIV_PROC))
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return(EPERM);
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/* System servers may not trace anyone. They can use sys_trace(). */
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if (mp->mp_flags & PRIV_PROC) return(EPERM);
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/* Can't trace self, PM or VM. */
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if (child == mp || child->mp_endpoint == PM_PROC_NR ||
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child->mp_endpoint == VM_PROC_NR) return(EPERM);
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/* Can't trace a process that is already being traced. */
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if (child->mp_tracer != NO_TRACER) return(EBUSY);
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child->mp_tracer = who_p;
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child->mp_trace_flags = TO_NOEXEC;
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sig_proc(child, SIGSTOP, TRUE /*trace*/, FALSE /* ksig */);
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mp->mp_reply.m_pm_lc_ptrace.data = 0;
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return(OK);
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case T_STOP: /* stop the process */
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/* This call is not exposed to user programs, because its effect can be
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* achieved better by sending the traced process a signal with kill(2).
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*/
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return(EINVAL);
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case T_READB_INS: /* special hack for reading text segments */
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if (mp->mp_effuid != SUPER_USER) return(EPERM);
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if ((child = find_proc(m_in.m_lc_pm_ptrace.pid)) == NULL) return(ESRCH);
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if (child->mp_flags & EXITING) return(ESRCH);
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r = sys_trace(req, child->mp_endpoint, m_in.m_lc_pm_ptrace.addr,
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&m_in.m_lc_pm_ptrace.data);
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if (r != OK) return(r);
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mp->mp_reply.m_pm_lc_ptrace.data = m_in.m_lc_pm_ptrace.data;
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return(OK);
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case T_WRITEB_INS: /* special hack for patching text segments */
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if (mp->mp_effuid != SUPER_USER) return(EPERM);
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if ((child = find_proc(m_in.m_lc_pm_ptrace.pid)) == NULL) return(ESRCH);
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if (child->mp_flags & EXITING) return(ESRCH);
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#if 0
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/* Should check for shared text */
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/* Make sure the text segment is not used as a source for shared
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* text.
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*/
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child->mp_ino = 0;
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child->mp_dev = 0;
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child->mp_ctime = 0;
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#endif
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r = sys_trace(req, child->mp_endpoint, m_in.m_lc_pm_ptrace.addr,
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&m_in.m_lc_pm_ptrace.data);
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if (r != OK) return(r);
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mp->mp_reply.m_pm_lc_ptrace.data = m_in.m_lc_pm_ptrace.data;
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return(OK);
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}
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/* All the other calls are made by the tracing process to control execution
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* of the child. For all these calls, the child must be stopped.
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*/
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if ((child = find_proc(m_in.m_lc_pm_ptrace.pid)) == NULL) return(ESRCH);
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if (child->mp_flags & EXITING) return(ESRCH);
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if (child->mp_tracer != who_p) return(ESRCH);
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if (!(child->mp_flags & TRACE_STOPPED)) return(EBUSY);
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switch (req) {
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case T_EXIT: /* exit */
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child->mp_flags |= TRACE_EXIT;
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/* Defer the exit if the traced process has an VFS call pending. */
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if (child->mp_flags & VFS_CALL)
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child->mp_exitstatus = m_in.m_lc_pm_ptrace.data; /* save it */
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else
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exit_proc(child, m_in.m_lc_pm_ptrace.data,
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FALSE /*dump_core*/);
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/* Do not reply to the caller until VFS has processed the exit
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* request.
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*/
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return(SUSPEND);
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case T_SETOPT: /* set trace options */
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child->mp_trace_flags = m_in.m_lc_pm_ptrace.data;
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mp->mp_reply.m_pm_lc_ptrace.data = 0;
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return(OK);
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case T_GETRANGE:
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case T_SETRANGE: /* get/set range of values */
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r = sys_datacopy(who_e, m_in.m_lc_pm_ptrace.addr, SELF, (vir_bytes)&pr,
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(phys_bytes)sizeof(pr));
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if (r != OK) return(r);
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if (pr.pr_space != TS_INS && pr.pr_space != TS_DATA) return(EINVAL);
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if (pr.pr_size == 0 || pr.pr_size > LONG_MAX) return(EINVAL);
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if (req == T_GETRANGE)
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r = sys_vircopy(child->mp_endpoint, (vir_bytes) pr.pr_addr,
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who_e, (vir_bytes) pr.pr_ptr,
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(phys_bytes) pr.pr_size, 0);
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else
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r = sys_vircopy(who_e, (vir_bytes) pr.pr_ptr,
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child->mp_endpoint, (vir_bytes) pr.pr_addr,
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(phys_bytes) pr.pr_size, 0);
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if (r != OK) return(r);
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mp->mp_reply.m_pm_lc_ptrace.data = 0;
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return(OK);
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case T_DETACH: /* detach from traced process */
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if (m_in.m_lc_pm_ptrace.data < 0 || m_in.m_lc_pm_ptrace.data >= _NSIG)
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return(EINVAL);
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child->mp_tracer = NO_TRACER;
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/* Let all tracer-pending signals through the filter. */
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for (i = 1; i < _NSIG; i++) {
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if (sigismember(&child->mp_sigtrace, i)) {
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sigdelset(&child->mp_sigtrace, i);
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check_sig(child->mp_pid, i, FALSE /* ksig */);
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}
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}
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if (m_in.m_lc_pm_ptrace.data > 0) { /* issue signal */
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sig_proc(child, m_in.m_lc_pm_ptrace.data, TRUE /*trace*/,
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FALSE /* ksig */);
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}
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/* Resume the child as if nothing ever happened. */
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child->mp_flags &= ~TRACE_STOPPED;
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child->mp_trace_flags = 0;
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check_pending(child);
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break;
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case T_RESUME:
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case T_STEP:
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case T_SYSCALL: /* resume execution */
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if (m_in.m_lc_pm_ptrace.data < 0 || m_in.m_lc_pm_ptrace.data >= _NSIG)
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return(EINVAL);
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if (m_in.m_lc_pm_ptrace.data > 0) { /* issue signal */
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sig_proc(child, m_in.m_lc_pm_ptrace.data, FALSE /*trace*/,
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FALSE /* ksig */);
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}
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/* If there are any other signals waiting to be delivered,
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* feign a successful resumption.
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*/
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for (i = 1; i < _NSIG; i++) {
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if (sigismember(&child->mp_sigtrace, i)) {
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mp->mp_reply.m_pm_lc_ptrace.data = 0;
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return(OK);
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}
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}
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child->mp_flags &= ~TRACE_STOPPED;
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check_pending(child);
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break;
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}
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r = sys_trace(req, child->mp_endpoint, m_in.m_lc_pm_ptrace.addr,
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&m_in.m_lc_pm_ptrace.data);
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if (r != OK) return(r);
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mp->mp_reply.m_pm_lc_ptrace.data = m_in.m_lc_pm_ptrace.data;
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return(OK);
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}
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/*===========================================================================*
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* trace_stop *
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*===========================================================================*/
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void trace_stop(rmp, signo)
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register struct mproc *rmp;
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int signo;
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{
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/* A traced process got a signal so stop it. */
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register struct mproc *rpmp = mproc + rmp->mp_tracer;
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int r;
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r = sys_trace(T_STOP, rmp->mp_endpoint, 0L, (long *) 0);
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if (r != OK) panic("sys_trace failed: %d", r);
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rmp->mp_flags |= TRACE_STOPPED;
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if (wait_test(rpmp, rmp)) {
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sigdelset(&rmp->mp_sigtrace, signo);
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rpmp->mp_flags &= ~WAITING; /* parent is no longer waiting */
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rpmp->mp_reply.m_pm_lc_waitpid.status = W_STOPCODE(signo);
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reply(rmp->mp_tracer, rmp->mp_pid);
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}
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}
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