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112 lines
2.8 KiB
C
112 lines
2.8 KiB
C
/* Change the protections of file relative to open directory. Linux version.
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Copyright (C) 2006-2014 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<http://www.gnu.org/licenses/>. */
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#include <errno.h>
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#include <fcntl.h>
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#include <stddef.h>
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#include <stdio.h>
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#include <string.h>
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#include <unistd.h>
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#include <sys/types.h>
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#include <alloca.h>
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#include <kernel-features.h>
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#include <sysdep.h>
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int
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fchmodat (fd, file, mode, flag)
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int fd;
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const char *file;
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mode_t mode;
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int flag;
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{
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if (flag & ~AT_SYMLINK_NOFOLLOW)
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{
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__set_errno (EINVAL);
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return -1;
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}
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#ifndef __NR_lchmod /* Linux so far has no lchmod syscall. */
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if (flag & AT_SYMLINK_NOFOLLOW)
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{
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__set_errno (ENOTSUP);
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return -1;
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}
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#endif
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int result;
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#ifdef __NR_fchmodat
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# ifndef __ASSUME_ATFCTS
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if (__have_atfcts >= 0)
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# endif
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{
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result = INLINE_SYSCALL (fchmodat, 3, fd, file, mode);
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# ifndef __ASSUME_ATFCTS
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if (result == -1 && errno == ENOSYS)
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__have_atfcts = -1;
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else
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# endif
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return result;
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}
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#endif
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#ifndef __ASSUME_ATFCTS
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char *buf = NULL;
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if (fd != AT_FDCWD && file[0] != '/')
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{
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size_t filelen = strlen (file);
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if (__glibc_unlikely (filelen == 0))
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{
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__set_errno (ENOENT);
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return -1;
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}
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static const char procfd[] = "/proc/self/fd/%d/%s";
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/* Buffer for the path name we are going to use. It consists of
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- the string /proc/self/fd/
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- the file descriptor number
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- the file name provided.
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The final NUL is included in the sizeof. A bit of overhead
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due to the format elements compensates for possible negative
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numbers. */
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size_t buflen = sizeof (procfd) + sizeof (int) * 3 + filelen;
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buf = alloca (buflen);
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__snprintf (buf, buflen, procfd, fd, file);
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file = buf;
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}
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INTERNAL_SYSCALL_DECL (err);
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# ifdef __NR_lchmod
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if (flag & AT_SYMLINK_NOFOLLOW)
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result = INTERNAL_SYSCALL (lchmod, err, 2, file, mode);
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else
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# endif
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result = INTERNAL_SYSCALL (chmod, err, 2, file, mode);
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if (__glibc_unlikely (INTERNAL_SYSCALL_ERROR_P (result, err)))
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{
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__atfct_seterrno (INTERNAL_SYSCALL_ERRNO (result, err), fd, buf);
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result = -1;
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}
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return result;
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#endif
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}
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