1/* Define an at-style functions like fstatat, unlinkat, fchownat, etc. 2 Copyright (C) 2006 Free Software Foundation, Inc. 3 4 This program is free software; you can redistribute it and/or modify 5 it under the terms of the GNU General Public License as published by 6 the Free Software Foundation; either version 2, or (at your option) 7 any later version. 8 9 This program is distributed in the hope that it will be useful, 10 but WITHOUT ANY WARRANTY; without even the implied warranty of 11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 12 GNU General Public License for more details. 13 14 You should have received a copy of the GNU General Public License 15 along with this program; if not, write to the Free Software Foundation, 16 Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */ 17 18/* written by Jim Meyering */ 19 20#define CALL_FUNC(F) \ 21 (AT_FUNC_USE_F1_COND \ 22 ? AT_FUNC_F1 (F AT_FUNC_POST_FILE_ARGS) \ 23 : AT_FUNC_F2 (F AT_FUNC_POST_FILE_ARGS)) 24 25/* Call AT_FUNC_F1 or AT_FUNC_F2 (testing AT_FUNC_USE_F1_COND to 26 determine which) to operate on FILE, which is in the directory 27 open on descriptor FD. If possible, do it without changing the 28 working directory. Otherwise, resort to using save_cwd/fchdir, 29 then AT_FUNC_F?/restore_cwd. If either the save_cwd or the restore_cwd 30 fails, then give a diagnostic and exit nonzero. */ 31int 32AT_FUNC_NAME (int fd, char const *file AT_FUNC_POST_FILE_PARAM_DECLS) 33{ 34 struct saved_cwd saved_cwd; 35 int saved_errno; 36 int err; 37 38 if (fd == AT_FDCWD || IS_ABSOLUTE_FILE_NAME (file)) 39 return CALL_FUNC (file); 40 41 { 42 char buf[OPENAT_BUFFER_SIZE]; 43 char *proc_file = openat_proc_name (buf, fd, file); 44 if (proc_file) 45 { 46 int proc_result = CALL_FUNC (proc_file); 47 int proc_errno = errno; 48 if (proc_file != buf) 49 free (proc_file); 50 /* If the syscall succeeds, or if it fails with an unexpected 51 errno value, then return right away. Otherwise, fall through 52 and resort to using save_cwd/restore_cwd. */ 53 if (0 <= proc_result) 54 return proc_result; 55 if (! EXPECTED_ERRNO (proc_errno)) 56 { 57 errno = proc_errno; 58 return proc_result; 59 } 60 } 61 } 62 63 if (save_cwd (&saved_cwd) != 0) 64 openat_save_fail (errno); 65 66 if (fchdir (fd) != 0) 67 { 68 saved_errno = errno; 69 free_cwd (&saved_cwd); 70 errno = saved_errno; 71 return -1; 72 } 73 74 err = CALL_FUNC (file); 75 saved_errno = (err < 0 ? errno : 0); 76 77 if (restore_cwd (&saved_cwd) != 0) 78 openat_restore_fail (errno); 79 80 free_cwd (&saved_cwd); 81 82 if (saved_errno) 83 errno = saved_errno; 84 return err; 85} 86#undef CALL_FUNC 87