gcc/libgo/runtime/go-varargs.c
Nikhil Benesch 439407aa2c syscall: only compile ptrace varargs shim on Linux
Only compile the __go_ptrace varargs shim on Linux to avoid compilation
failures on some other platforms. The C ptrace function is not entirely
portable (e.g., NetBSD has `int data` instead of `void* data`), and so
far Linux is the only platform that needs the varargs shim.

Additionally, make the types in the ptrace and raw_ptrace function
declarations match. This makes it more clear that the only difference
between the two is that calls via the former are allowed to block while
calls via the latter are not.

Reviewed-on: https://go-review.googlesource.com/c/gofrontend/+/263517
2020-10-21 22:29:04 -07:00

130 lines
2.6 KiB
C

/* go-varargs.c -- functions for calling C varargs functions.
Copyright 2013 The Go Authors. All rights reserved.
Use of this source code is governed by a BSD-style
license that can be found in the LICENSE file. */
#include "config.h"
#include <errno.h>
#include <stdint.h>
#include <unistd.h>
#include <sys/types.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#ifdef HAVE_SYSCALL_H
#include <syscall.h>
#endif
#ifdef HAVE_SYS_SYSCALL_H
#include <sys/syscall.h>
#endif
#ifdef HAVE_SYS_PTRACE_H
#include <sys/ptrace.h>
#endif
/* The syscall package calls C functions. The Go compiler can not
represent a C varargs functions. On some systems it's important
that the declaration of a function match the call. This function
holds non-varargs C functions that the Go code can call. */
int
__go_open (char *path, int mode, mode_t perm)
{
return open (path, mode, perm);
}
int
__go_fcntl (int fd, int cmd, int arg)
{
return fcntl (fd, cmd, arg);
}
int
__go_fcntl_flock (int fd, int cmd, struct flock *arg)
{
return fcntl (fd, cmd, arg);
}
// This is for the net package. We use uintptr_t to make sure that
// the types match, since the Go and C "int" types are not the same.
struct go_fcntl_ret {
uintptr_t r;
uintptr_t err;
};
struct go_fcntl_ret
__go_fcntl_uintptr (uintptr_t fd, uintptr_t cmd, uintptr_t arg)
{
int r;
struct go_fcntl_ret ret;
r = fcntl ((int) fd, (int) cmd, (int) arg);
ret.r = (uintptr_t) r;
if (r < 0)
ret.err = (uintptr_t) errno;
else
ret.err = 0;
return ret;
}
int
__go_ioctl (int d, int request, int arg)
{
return ioctl (d, request, arg);
}
int
__go_ioctl_ptr (int d, int request, void *arg)
{
return ioctl (d, request, arg);
}
#ifdef HAVE_OPEN64
int
__go_open64 (char *path, int mode, mode_t perm)
{
return open64 (path, mode, perm);
}
#endif
#ifdef HAVE_OPENAT
int
__go_openat (int fd, char *path, int flags, mode_t mode)
{
return openat (fd, path, flags, mode);
}
#endif
#ifdef HAVE_SYSCALL
// __go_syscall6 is called by both the runtime and syscall packages.
// We use uintptr_t to make sure that the types match, since the Go
// and C "int" types are not the same.
uintptr_t
__go_syscall6(uintptr_t flag, uintptr_t a1, uintptr_t a2, uintptr_t a3,
uintptr_t a4, uintptr_t a5, uintptr_t a6)
{
return syscall (flag, a1, a2, a3, a4, a5, a6);
}
#endif
#if defined(HAVE_SYS_PTRACE_H) && defined(__linux__)
// Despite documented appearances, this is actually implemented as
// a variadic function within glibc on Linux.
long
__go_ptrace(int request, pid_t pid, void *addr, void *data)
{
return ptrace (request, pid, addr, data);
}
#endif