| /* chown() compatibility. |
| Copyright (C) 1998, 2000, 2002, 2003, 2005 Free Software Foundation, Inc. |
| This file is part of the GNU C Library. |
| |
| The GNU C Library is free software; you can redistribute it and/or |
| modify it under the terms of the GNU Lesser General Public |
| License as published by the Free Software Foundation; either |
| version 2.1 of the License, or (at your option) any later version. |
| |
| The GNU C Library is distributed in the hope that it will be useful, |
| but WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| Lesser General Public License for more details. |
| |
| You should have received a copy of the GNU Lesser General Public |
| License along with the GNU C Library; if not, write to the Free |
| Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA |
| 02111-1307 USA. */ |
| |
| #include <errno.h> |
| #include <string.h> |
| #include <unistd.h> |
| #include <limits.h> |
| #include <sysdep.h> |
| #include <stdlib.h> |
| |
| #include <kernel-features.h> |
| |
| /* |
| In Linux 2.1.x the chown functions have been changed. A new function lchown |
| was introduced. The new chown now follows symlinks - the old chown and the |
| new lchown do not follow symlinks. |
| This file emulates chown() under the old kernels. |
| */ |
| |
| int |
| __chown (const char *file, uid_t owner, gid_t group) |
| { |
| #if __ASSUME_LCHOWN_SYSCALL |
| return INLINE_SYSCALL (chown, 3, file, owner, group); |
| #else |
| int err; |
| int old_errno; |
| char link[PATH_MAX + 2]; |
| char path[2 * PATH_MAX + 4]; |
| int loopct; |
| size_t filelen; |
| static int libc_old_chown = 0 /* -1=old linux, 1=new linux, 0=unknown */; |
| |
| if (libc_old_chown == 1) |
| return INLINE_SYSCALL (chown, 3, __ptrvalue (file), owner, group); |
| |
| old_errno = errno; |
| |
| # ifdef __NR_lchown |
| if (libc_old_chown == 0) |
| { |
| err = INLINE_SYSCALL (chown, 3, __ptrvalue (file), owner, group); |
| if (err != -1 || errno != ENOSYS) |
| { |
| libc_old_chown = 1; |
| return err; |
| } |
| libc_old_chown = -1; |
| } |
| # endif |
| |
| err = __readlink (file, link, PATH_MAX + 1); |
| if (err == -1) |
| { |
| __set_errno (old_errno); |
| return __lchown (file, owner, group); |
| } |
| |
| filelen = strlen (file) + 1; |
| if (filelen > sizeof (path)) |
| { |
| __set_errno (ENAMETOOLONG); |
| return -1; |
| } |
| memcpy (path, file, filelen); |
| |
| /* 'The system has an arbitrary limit...' In practise, we'll hit |
| ENAMETOOLONG before this, usually. */ |
| for (loopct = 0; loopct < 128; ++loopct) |
| { |
| size_t linklen; |
| |
| if (err >= PATH_MAX + 1) |
| { |
| __set_errno (ENAMETOOLONG); |
| return -1; |
| } |
| |
| link[err] = 0; /* Null-terminate string, just-in-case. */ |
| |
| linklen = strlen (link) + 1; |
| |
| if (link[0] == '/') |
| memcpy (path, link, linklen); |
| else |
| { |
| filelen = strlen (path); |
| |
| while (filelen > 1 && path[filelen - 1] == '/') |
| --filelen; |
| while (filelen > 0 && path[filelen - 1] != '/') |
| --filelen; |
| if (filelen + linklen > sizeof (path)) |
| { |
| errno = ENAMETOOLONG; |
| return -1; |
| } |
| memcpy (path + filelen, link, linklen); |
| } |
| |
| err = __readlink (path, link, PATH_MAX + 1); |
| |
| if (err == -1) |
| { |
| __set_errno (old_errno); |
| return __lchown (path, owner, group); |
| } |
| } |
| __set_errno (ELOOP); |
| return -1; |
| #endif |
| } |
| libc_hidden_def (__chown) |
| |
| #include <shlib-compat.h> |
| versioned_symbol (libc, __chown, chown, GLIBC_2_1); |