getgrouplist_unix.go

Documentation: os/user

		 1  // Copyright 2016 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 (dragonfly || freebsd || (!android && linux) || netbsd || openbsd || (solaris && !illumos)) && cgo && !osusergo
		 6  // +build dragonfly freebsd !android,linux netbsd openbsd solaris,!illumos
		 7  // +build cgo
		 8  // +build !osusergo
		 9  
		10  package user
		11  
		12  /*
		13  #include <unistd.h>
		14  #include <sys/types.h>
		15  #include <grp.h>
		16  
		17  static int mygetgrouplist(const char* user, gid_t group, gid_t* groups, int* ngroups) {
		18  	return getgrouplist(user, group, groups, ngroups);
		19  }
		20  */
		21  import "C"
		22  import (
		23  	"fmt"
		24  	"unsafe"
		25  )
		26  
		27  func getGroupList(name *C.char, userGID C.gid_t, gids *C.gid_t, n *C.int) C.int {
		28  	return C.mygetgrouplist(name, userGID, gids, n)
		29  }
		30  
		31  // groupRetry retries getGroupList with much larger size for n. The result is
		32  // stored in gids.
		33  func groupRetry(username string, name []byte, userGID C.gid_t, gids *[]C.gid_t, n *C.int) error {
		34  	// More than initial buffer, but now n contains the correct size.
		35  	if *n > maxGroups {
		36  		return fmt.Errorf("user: %q is a member of more than %d groups", username, maxGroups)
		37  	}
		38  	*gids = make([]C.gid_t, *n)
		39  	rv := getGroupList((*C.char)(unsafe.Pointer(&name[0])), userGID, &(*gids)[0], n)
		40  	if rv == -1 {
		41  		return fmt.Errorf("user: list groups for %s failed", username)
		42  	}
		43  	return nil
		44  }
		45
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