github.com/afumu/libc@v0.0.6/musl/src/linux/ptrace.c (about)

     1  #include <sys/ptrace.h>
     2  #include <stdarg.h>
     3  #include <unistd.h>
     4  #include "syscall.h"
     5  
     6  long ptrace(int req, ...)
     7  {
     8  	va_list ap;
     9  	pid_t pid;
    10  	void *addr, *data, *addr2 = 0;
    11  	long ret, result;
    12  
    13  	va_start(ap, req);
    14  	pid = va_arg(ap, pid_t);
    15  	addr = va_arg(ap, void *);
    16  	data = va_arg(ap, void *);
    17  	/* PTRACE_{READ,WRITE}{DATA,TEXT} (16...19) are specific to SPARC. */
    18  #ifdef PTRACE_READDATA
    19  	if ((unsigned)req - PTRACE_READDATA < 4)
    20  		addr2 = va_arg(ap, void *);
    21  #endif
    22  	va_end(ap);
    23  
    24  	if (req-1U < 3) data = &result;
    25  	ret = syscall(SYS_ptrace, req, pid, addr, data, addr2);
    26  
    27  	if (ret < 0 || req-1U >= 3) return ret;
    28  	return result;
    29  }