Resume the process that's associated with the file descriptor, if it has previously been stopped.

#include <sys/procfs.h>

#define DCMD_PROC_RUN32  (__DIOT(_DCMD_PROC, __PROC_SUBCMD_PROCFS + 9, procfs_run32))
#define DCMD_PROC_RUN64  (__DIOT(_DCMD_PROC, __PROC_SUBCMD_PROCFS + 9, procfs_run64))
#define DCMD_PROC_RUN    (__DIOT(_DCMD_PROC, __PROC_SUBCMD_PROCFS + 9, procfs_run))
Note: The generic command maps onto the 64-bit version, unless you're compiling for a 32-bit architecture and you define WANT_OLD_DEVCTLS before you include <sys/procfs.h>.

The arguments to devctl() are:

Argument Value
filedes A file descriptor for the process. You must have opened the file descriptor for writing.
dev_data_ptr A pointer to a procfs_run structure
n_bytes sizeof(procfs_run)
dev_info_ptr NULL

To stop the process, use DCMD_PROC_STOP. The DCMD_PROC_RUN command also lets you set the “points of interest” (e.g., signals or faults you want to stop on) and other run flags (e.g., instruction pointer or single-step).

The argument is a pointer to a procfs_run structure (see debug_run_t in <sys/debug.h>). This structure is passed on as control information to the process before it resumes. For example:

procfs_run      run;

memset( &run, 0, sizeof(run) );
devctl( fd, DCMD_PROC_RUN, &run, sizeof(run), NULL);

The procfs_run or debug_run_t structure is defined for 64-bit architectures as follows:

typedef struct _debug_run64 {
    uint32_t                    flags;
    pthread_t                   tid;
    sigset_t                    trace;
    sigset_t                    hold;
    fltset_t                    fault;
    uintptr32_t                 __ip;
    uintptr64_t                 ip;
} debug_run_t;

The members include:

A combination of zero or more of the following bits:
  • _DEBUG_RUN_CLRSIG — clear pending signal.
  • _DEBUG_RUN_CLRFLT — clear pending fault.
  • _DEBUG_RUN_TRACE — the trace mask flags interesting signals.
  • _DEBUG_RUN_FAULT — the fault mask flags interesting faults.
  • _DEBUG_RUN_VADDR — change ip before running.
  • _DEBUG_RUN_STEP — single-step only one thread.
  • _DEBUG_RUN_STEP_ALL — single-step one thread; other threads run.
  • _DEBUG_RUN_CURTID — change the current thread (target thread) to the one whose thread ID is specified by tid.
  • _DEBUG_RUN_ARM — deliver an event at the point of interest. Use the DCMD_PROC_EVENT command to define the event.
The ID of the thread that you want to become the current thread, for use with _DEBUG_RUN_CURTID.
A set of signals (SIG*) to trace, for use with _DEBUG_RUN_TRACE.
Not currently used.
A set of faults (FLT*) to trace, for use with _DEBUG_RUN_FAULT.
The new value for the instruction pointer, for use with _DEBUG_RUN_VADDR.

Use sigemptyset() and sigaddset() to build the set of signals or faults for the trace, hold and fault members.