run_child

Syntax

#include <debug/dbgcom.h> void run_child (void);

Description

This function starts or resumes the debugged program, via a longjmp to the debuggee's code. When the debuggee hits a breakpoint, or exits normally, the exception handler that is called to service the breakpoint exception will longjmp back to run_child, and it will then return to the caller.

After run_child returns, the debugger usually examines the a_tss variable to find out the reason the debuggee stopped. The a_tss variable is defined by the header `debug/tss.h' as follows:

typedef struct TSS { unsigned short tss_back_link; unsigned short res0; unsigned long tss_esp0; unsigned short tss_ss0; unsigned short res1; unsigned long tss_esp1; unsigned short tss_ss1; unsigned short res2; unsigned long tss_esp2; unsigned short tss_ss2; unsigned short res3; unsigned long tss_cr3; unsigned long tss_eip; unsigned long tss_eflags; unsigned long tss_eax; unsigned long tss_ecx; unsigned long tss_edx; unsigned long tss_ebx; unsigned long tss_esp; unsigned long tss_ebp; unsigned long tss_esi; unsigned long tss_edi; unsigned short tss_es; unsigned short res4; unsigned short tss_cs; unsigned short res5; unsigned short tss_ss; unsigned short res6; unsigned short tss_ds; unsigned short res7; unsigned short tss_fs; unsigned short res8; unsigned short tss_gs; unsigned short res9; unsigned short tss_ldt; unsigned short res10; unsigned short tss_trap; unsigned char tss_iomap; unsigned char tss_irqn; unsigned long tss_error; } TSS; extern TSS a_tss;

See the example below for a typical tests after run_child returns.

Note that, generally, you'd need to save the standard handles before calling run_child and restore them after it returns. Otherwise, if the debuggee redirects one of its standard handles, the corresponding debugger's standard handle is redirected as well. See section redir_to_child, and see redir_to_debugger.

Portability

ANSI/ISO C	No
POSIX	No

Example

save_npx (); run_child (); load_npx (); if (a_tss.tss_irqn == 0x21) { status = DEBUGGEE_EXITED; exit_code = a_tss.tss_eax & 0xff; } else { status = DEBUGGEE_GOT_SIGNAL if (a_tss.tss_irqn == 0x75) signal_number = SIGINT; else if (a_tss.tss_irqn == 1 || a_tss.tss_irqn == 3) signal_number = SIGTRAP; /* a breakpoint */ }