func lookupUnix(gid int, groupname string, lookupByName bool) (*Group, error) {
var grp C.struct_group
var result *C.struct_group
var bufSize C.long
if runtime.GOOS == "freebsd" {
panic("Don't know how to deal with freebsd.")
} else {
bufSize = C.sysconf(C._SC_GETGR_R_SIZE_MAX) * 20
if bufSize <= 0 || bufSize > 1<<20 {
return nil, fmt.Errorf("group: unreasonable _SC_GETGR_R_SIZE_MAX of %d", bufSize)
}
}
buf := C.malloc(C.size_t(bufSize))
defer C.free(buf)
var rv C.int
if lookupByName {
nameC := C.CString(groupname)
defer C.free(unsafe.Pointer(nameC))
rv = C.getgrnam_r(nameC,
&grp,
(*C.char)(buf),
C.size_t(bufSize),
&result)
if rv != 0 {
return nil, fmt.Errorf("group: lookup groupname %s: %s", groupname, syscall.Errno(rv))
}
if result == nil {
return nil, UnknownGroupError(groupname)
}
} else {
rv = C.getgrgid_r(C.__gid_t(gid),
&grp,
(*C.char)(buf),
C.size_t(bufSize),
&result)
if rv != 0 {
return nil, fmt.Errorf("group: lookup groupid %d: %s", gid, syscall.Errno(rv))
}
if result == nil {
return nil, UnknownGroupIdError(gid)
}
}
u := &Group{
Gid: strconv.Itoa(int(grp.gr_gid)),
Groupname: C.GoString(grp.gr_name),
}
return u, nil
}
func lookup(gid int, groupname string, lookupByName bool) (*Group, error) {
var grp C.struct_group
var result *C.struct_group
var bufsize C.long
bufsize = C.sysconf(C._SC_GETGR_R_SIZE_MAX)
if bufsize == -1 {
bufsize = 1024
}
buf := C.malloc(C.size_t(bufsize))
defer C.free(buf)
var rv C.int
if lookupByName {
CGroup := C.CString(groupname)
defer C.free(unsafe.Pointer(CGroup))
rv = C.getgrnam_r(CGroup, &grp, (*C.char)(buf),
C.size_t(bufsize), &result)
if rv != 0 {
return nil,
fmt.Errorf("group: lookup group name %s: %s",
groupname, syscall.Errno(rv))
}
if result == nil {
return nil, UnknownGroupError(groupname)
}
} else {
rv = C.getgrgid_r(C.gid_t(gid), &grp, (*C.char)(buf),
C.size_t(bufsize), &result)
if rv != 0 {
return nil, fmt.Errorf("group: lookup gid %d: %s",
gid, syscall.Errno(rv))
}
if result == nil {
return nil, UnknownGroupIdError(gid)
}
}
g := &Group{
Gid: int(grp.gr_gid),
Name: C.GoString(grp.gr_name),
Members: convert(grp.gr_mem),
}
return g, nil
}