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657acd6c04
* sysdeps/mach/hurd/getcwd.c (_hurd_canonicalize_directory_name_internal): Do not loop forever for unknown root directories. (__getcwd): Return NULL when the current root directory could not be reached.
324 lines
9.0 KiB
C
324 lines
9.0 KiB
C
/* Copyright (C) 1991, 92, 93, 94, 95, 96, 97, 98 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 Library General Public License as
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published by the Free Software Foundation; either version 2 of the
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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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Library General Public License for more details.
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You should have received a copy of the GNU Library General Public
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License along with the GNU C Library; see the file COPYING.LIB. If not,
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write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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Boston, MA 02111-1307, USA. */
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#include <errno.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <hurd.h>
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#include <hurd/port.h>
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#include <dirent.h>
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#include <unistd.h>
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#include <stdlib.h>
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#include <string.h>
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#include <stdio.h>
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#include <fcntl.h>
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/* Get the canonical absolute name of the given directory port, and put it
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in SIZE bytes of BUF. Returns NULL if the directory couldn't be
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determined or SIZE was too small. If successful, returns BUF. In GNU,
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if BUF is NULL, an array is allocated with `malloc'; the array is SIZE
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bytes long, unless SIZE <= 0, in which case it is as big as necessary.
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If our root directory cannot be reached, the result will not begin with
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a slash to indicate that it is relative to some unknown root directory. */
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char *
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_hurd_canonicalize_directory_name_internal (file_t thisdir,
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char *buf,
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size_t size)
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{
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error_t err;
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mach_port_t rootid, thisid, rootdevid, thisdevid;
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ino_t rootino, thisino;
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char *file_name;
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register char *file_namep;
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file_t parent;
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char *dirbuf = NULL;
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unsigned int dirbufsize = 0;
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inline void cleanup (void)
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{
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if (parent != thisdir)
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__mach_port_deallocate (__mach_task_self (), parent);
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__mach_port_deallocate (__mach_task_self (), thisid);
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__mach_port_deallocate (__mach_task_self (), thisdevid);
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__mach_port_deallocate (__mach_task_self (), rootid);
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__mach_port_deallocate (__mach_task_self (), rootdevid);
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if (dirbuf != NULL)
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__vm_deallocate (__mach_task_self (),
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(vm_address_t) dirbuf, dirbufsize);
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}
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if (size == 0)
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{
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if (buf != NULL)
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{
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errno = EINVAL;
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return NULL;
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}
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size = FILENAME_MAX * 4 + 1; /* Good starting guess. */
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}
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if (buf != NULL)
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file_name = buf;
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else
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{
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file_name = malloc (size);
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if (file_name == NULL)
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return NULL;
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}
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file_namep = file_name + size;
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*--file_namep = '\0';
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/* Get a port to our root directory and get its identity. */
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if (err = __USEPORT (CRDIR, __io_identity (port,
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&rootid, &rootdevid, &rootino)))
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return __hurd_fail (err), NULL;
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__mach_port_deallocate (__mach_task_self (), rootdevid);
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/* Stat the port to the directory of interest. */
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if (err = __io_identity (thisdir, &thisid, &thisdevid, &thisino))
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{
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__mach_port_deallocate (__mach_task_self (), rootid);
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return __hurd_fail (err), NULL;
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}
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parent = thisdir;
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while (thisid != rootid)
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{
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/* PARENT is a port to the directory we are currently on;
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THISID, THISDEV, and THISINO are its identity.
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Look in its parent (..) for a file with the same file number. */
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struct dirent *d;
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mach_port_t dotid, dotdevid;
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ino_t dotino;
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int mount_point;
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file_t newp;
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char *dirdata;
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unsigned int dirdatasize;
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int direntry, nentries;
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/* Look at the parent directory. */
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newp = __file_name_lookup_under (parent, "..", O_READ, 0);
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if (newp == MACH_PORT_NULL)
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goto lose;
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if (parent != thisdir)
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__mach_port_deallocate (__mach_task_self (), parent);
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parent = newp;
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/* Get this directory's identity and figure out if it's a mount
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point. */
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if (err = __io_identity (parent, &dotid, &dotdevid, &dotino))
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goto errlose;
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mount_point = dotdevid != thisdevid;
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if (thisid == dotid)
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{
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/* `..' == `.' but it is not our root directory. */
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__mach_port_deallocate (__mach_task_self (), dotid);
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__mach_port_deallocate (__mach_task_self (), dotdevid);
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break;
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}
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/* Search for the last directory. */
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direntry = 0;
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dirdata = dirbuf;
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dirdatasize = dirbufsize;
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while (!(err = __dir_readdir (parent, &dirdata, &dirdatasize,
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direntry, -1, 0, &nentries)) &&
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nentries != 0)
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{
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/* We have a block of directory entries. */
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unsigned int offset;
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direntry += nentries;
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if (dirdata != dirbuf)
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{
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/* The data was passed out of line, so our old buffer is no
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longer useful. Deallocate the old buffer and reset our
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information for the new buffer. */
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__vm_deallocate (__mach_task_self (),
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(vm_address_t) dirbuf, dirbufsize);
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dirbuf = dirdata;
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dirbufsize = round_page (dirdatasize);
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}
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/* Iterate over the returned directory entries, looking for one
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whose file number is THISINO. */
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offset = 0;
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while (offset < dirdatasize)
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{
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d = (struct dirent *) &dirdata[offset];
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offset += d->d_reclen;
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/* Ignore `.' and `..'. */
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if (d->d_name[0] == '.' &&
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(d->d_namlen == 1 ||
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(d->d_namlen == 2 && d->d_name[1] == '.')))
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continue;
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if (mount_point || d->d_ino == thisino)
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{
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file_t try = __file_name_lookup_under (parent, d->d_name,
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O_NOLINK, 0);
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file_t id, devid;
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ino_t fileno;
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if (try == MACH_PORT_NULL)
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goto lose;
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err = __io_identity (try, &id, &devid, &fileno);
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__mach_port_deallocate (__mach_task_self (), try);
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if (err)
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goto inner_errlose;
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__mach_port_deallocate (__mach_task_self (), id);
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__mach_port_deallocate (__mach_task_self (), devid);
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if (id == thisid)
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goto found;
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}
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}
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}
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if (err)
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{
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inner_errlose: /* Goto ERRLOSE: after cleaning up. */
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__mach_port_deallocate (__mach_task_self (), dotid);
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__mach_port_deallocate (__mach_task_self (), dotdevid);
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goto errlose;
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}
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else if (nentries == 0)
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{
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/* We got to the end of the directory without finding anything!
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We are in a directory that has been unlinked, or something is
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broken. */
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err = ENOENT;
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goto inner_errlose;
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}
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else
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found:
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{
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/* Prepend the directory name just discovered. */
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if (file_namep - file_name < d->d_namlen + 1)
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{
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if (buf != NULL)
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{
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errno = ERANGE;
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return NULL;
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}
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else
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{
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size *= 2;
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buf = realloc (file_name, size);
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if (buf == NULL)
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{
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free (file_name);
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return NULL;
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}
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file_namep = &buf[file_namep - file_name + size / 2];
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file_name = buf;
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/* Move current contents up to the end of the buffer.
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This is guaranteed to be non-overlapping. */
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memcpy (file_namep, file_namep - size / 2,
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file_name + size - file_namep);
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}
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}
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file_namep -= d->d_namlen;
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(void) memcpy (file_namep, d->d_name, d->d_namlen);
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*--file_namep = '/';
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}
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/* The next iteration will find the name of the directory we
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just searched through. */
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__mach_port_deallocate (__mach_task_self (), thisid);
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__mach_port_deallocate (__mach_task_self (), thisdevid);
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thisid = dotid;
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thisdevid = dotdevid;
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thisino = dotino;
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}
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if (file_namep == &file_name[size - 1])
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/* We found nothing and got all the way to the root.
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So the root is our current directory. */
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*--file_namep = '/';
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if (thisid != rootid)
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/* We did not get to our root directory. The returned name should
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not begin with a slash. */
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++file_namep;
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memmove (file_name, file_namep, file_name + size - file_namep);
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cleanup ();
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return file_name;
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errlose:
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/* Set errno. */
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(void) __hurd_fail (err);
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lose:
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cleanup ();
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return NULL;
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}
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char *
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__canonicalize_directory_name_internal (thisdir, buf, size)
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const char *thisdir;
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char *buf;
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size_t size;
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{
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char *result;
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file_t port = __file_name_lookup (thisdir, 0, 0);
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if (port == MACH_PORT_NULL)
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return NULL;
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result = _hurd_canonicalize_directory_name_internal (port, buf, size);
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__mach_port_deallocate (__mach_task_self (), port);
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return result;
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}
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/* Get the pathname of the current working directory, and put it in SIZE
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bytes of BUF. Returns NULL if the directory couldn't be determined or
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SIZE was too small. If successful, returns BUF. In GNU, if BUF is
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NULL, an array is allocated with `malloc'; the array is SIZE bytes long,
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unless SIZE <= 0, in which case it is as big as necessary. */
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char *
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__getcwd (char *buf, size_t size)
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{
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char *cwd =
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__USEPORT (CWDIR,
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_hurd_canonicalize_directory_name_internal (port,
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buf, size));
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if (cwd && cwd[0] != '/')
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{
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/* `cwd' is an unknown root directory. */
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if (buf == NULL)
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free (cwd);
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return __hurd_fail (EGRATUITOUS), NULL;
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}
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return cwd;
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}
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weak_alias (__getcwd, getcwd)
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