linux_syscall.c

     1  // Copyright 2019 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  //go:build linux
     6  
     7  #ifndef _GNU_SOURCE // setres[ug]id() API.
     8  #define _GNU_SOURCE
     9  #endif
    10  
    11  #include <grp.h>
    12  #include <sys/types.h>
    13  #include <unistd.h>
    14  #include <errno.h>
    15  #include "libcgo.h"
    16  
    17  /*
    18   * Assumed POSIX compliant libc system call wrappers. For linux, the
    19   * glibc/nptl/setxid mechanism ensures that POSIX semantics are
    20   * honored for all pthreads (by default), and this in turn with cgo
    21   * ensures that all Go threads launched with cgo are kept in sync for
    22   * these function calls.
    23   */
    24  
    25  // argset_t matches runtime/cgocall.go:argset.
    26  typedef struct {
    27  	uintptr_t* args;
    28  	uintptr_t retval;
    29  } argset_t;
    30  
    31  // libc backed posix-compliant syscalls.
    32  
    33  #define SET_RETVAL(fn) \
    34    uintptr_t ret = (uintptr_t) fn ; \
    35    if (ret == (uintptr_t) -1) {	   \
    36      x->retval = (uintptr_t) errno; \
    37    } else                           \
    38      x->retval = ret
    39  
    40  void
    41  _cgo_libc_setegid(argset_t* x) {
    42  	SET_RETVAL(setegid((gid_t) x->args[0]));
    43  }
    44  
    45  void
    46  _cgo_libc_seteuid(argset_t* x) {
    47  	SET_RETVAL(seteuid((uid_t) x->args[0]));
    48  }
    49  
    50  void
    51  _cgo_libc_setgid(argset_t* x) {
    52  	SET_RETVAL(setgid((gid_t) x->args[0]));
    53  }
    54  
    55  void
    56  _cgo_libc_setgroups(argset_t* x) {
    57  	SET_RETVAL(setgroups((size_t) x->args[0], (const gid_t *) x->args[1]));
    58  }
    59  
    60  void
    61  _cgo_libc_setregid(argset_t* x) {
    62  	SET_RETVAL(setregid((gid_t) x->args[0], (gid_t) x->args[1]));
    63  }
    64  
    65  void
    66  _cgo_libc_setresgid(argset_t* x) {
    67  	SET_RETVAL(setresgid((gid_t) x->args[0], (gid_t) x->args[1],
    68  			     (gid_t) x->args[2]));
    69  }
    70  
    71  void
    72  _cgo_libc_setresuid(argset_t* x) {
    73  	SET_RETVAL(setresuid((uid_t) x->args[0], (uid_t) x->args[1],
    74  			     (uid_t) x->args[2]));
    75  }
    76  
    77  void
    78  _cgo_libc_setreuid(argset_t* x) {
    79  	SET_RETVAL(setreuid((uid_t) x->args[0], (uid_t) x->args[1]));
    80  }
    81  
    82  void
    83  _cgo_libc_setuid(argset_t* x) {
    84  	SET_RETVAL(setuid((uid_t) x->args[0]));
    85  }
    86
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