diff options
Diffstat (limited to 'libnetfs/dir-lookup.c')
| -rw-r--r-- | libnetfs/dir-lookup.c | 376 |
1 files changed, 376 insertions, 0 deletions
diff --git a/libnetfs/dir-lookup.c b/libnetfs/dir-lookup.c new file mode 100644 index 00000000..5019017b --- /dev/null +++ b/libnetfs/dir-lookup.c @@ -0,0 +1,376 @@ +/* + Copyright (C) 1995,96,97,98,99,2000 Free Software Foundation, Inc. + Written by Michael I. Bushnell, p/BSG. + + This file is part of the GNU Hurd. + + The GNU Hurd is free software; you can redistribute it and/or + modify it under the terms of the GNU General Public License as + published by the Free Software Foundation; either version 2, or (at + your option) any later version. + + The GNU Hurd 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 + General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program; if not, write to the Free Software + Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111, USA. */ + +#include <fcntl.h> +#include <assert.h> +#include <string.h> +#include <stdio.h> +#include <hurd/paths.h> +#include "netfs.h" +#include "fs_S.h" +#include "callbacks.h" +#include "misc.h" + +error_t +netfs_S_dir_lookup (struct protid *diruser, + char *filename, + int flags, + mode_t mode, + retry_type *do_retry, + char *retry_name, + mach_port_t *retry_port, + mach_msg_type_name_t *retry_port_type) +{ + int create; /* true if O_CREAT flag set */ + int excl; /* true if O_EXCL flag set */ + int mustbedir = 0; /* true if the result must be S_IFDIR */ + int lastcomp = 0; /* true if we are at the last component */ + int newnode = 0; /* true if this node is newly created */ + int nsymlinks = 0; + struct node *dnp, *np; + char *nextname; + error_t error; + struct protid *newpi; + + if (!diruser) + return EOPNOTSUPP; + + create = (flags & O_CREAT); + excl = (flags & O_EXCL); + + /* Skip leading slashes */ + while (*filename == '/') + filename++; + + *retry_port_type = MACH_MSG_TYPE_MAKE_SEND; + *do_retry = FS_RETRY_NORMAL; + *retry_name = '\0'; + + if (*filename == '\0') + { + /* Set things up in the state expected by the code from gotit: on. */ + dnp = 0; + np = diruser->po->np; + mutex_lock (&np->lock); + netfs_nref (np); + goto gotit; + } + + dnp = diruser->po->np; + mutex_lock (&dnp->lock); + np = 0; + + netfs_nref (dnp); /* acquire a reference for later netfs_nput */ + + do + { + assert (!lastcomp); + + /* Find the name of the next pathname component */ + nextname = index (filename, '/'); + + if (nextname) + { + *nextname++ = '\0'; + while (*nextname == '/') + nextname++; + if (*nextname == '\0') + { + /* These are the rules for filenames ending in /. */ + nextname = 0; + lastcomp = 1; + mustbedir = 1; + create = 0; + } + else + lastcomp = 0; + } + else + lastcomp = 1; + + np = 0; + + retry_lookup: + + if ((dnp == netfs_root_node || dnp == diruser->po->shadow_root) + && filename[0] == '.' && filename[1] == '.' && filename[2] == '\0') + if (dnp == diruser->po->shadow_root) + /* We're at the root of a shadow tree. */ + { + *do_retry = FS_RETRY_REAUTH; + *retry_port = diruser->po->shadow_root_parent; + *retry_port_type = MACH_MSG_TYPE_COPY_SEND; + if (! lastcomp) + strcpy (retry_name, nextname); + error = 0; + mutex_unlock (&dnp->lock); + goto out; + } + else if (diruser->po->root_parent != MACH_PORT_NULL) + /* We're at a real translator root; even if DIRUSER->po has a + shadow root, we can get here if its in a directory that was + renamed out from under it... */ + { + *do_retry = FS_RETRY_REAUTH; + *retry_port = diruser->po->root_parent; + *retry_port_type = MACH_MSG_TYPE_COPY_SEND; + if (!lastcomp) + strcpy (retry_name, nextname); + error = 0; + mutex_unlock (&dnp->lock); + goto out; + } + else + /* We are global root */ + { + error = 0; + np = dnp; + netfs_nref (np); + } + else + /* Attempt a lookup on the next pathname component. */ + error = netfs_attempt_lookup (diruser->user, dnp, filename, &np); + + /* At this point, DNP is unlocked */ + + /* Implement O_EXCL flag here */ + if (lastcomp && create && excl && !error) + error = EEXIST; + + /* Create the new node if necessary */ + if (lastcomp && create && error == ENOENT) + { + mode &= ~(S_IFMT | S_ISPARE | S_ISVTX); + mode |= S_IFREG; + mutex_lock (&dnp->lock); + error = netfs_attempt_create_file (diruser->user, dnp, + filename, mode, &np); + + /* If someone has already created the file (between our lookup + and this create) then we just got EEXIST. If we are + EXCL, that's fine; otherwise, we have to retry the lookup. */ + if (error == EEXIST && !excl) + { + mutex_lock (&dnp->lock); + goto retry_lookup; + } + + newnode = 1; + } + + /* All remaining errors get returned to the user */ + if (error) + goto out; + + error = netfs_validate_stat (np, diruser->user); + if (error) + goto out; + + if ((((flags & O_NOTRANS) == 0) || !lastcomp) + && ((np->nn_stat.st_mode & S_IPTRANS) + || S_ISFIFO (np->nn_stat.st_mode) + || S_ISCHR (np->nn_stat.st_mode) + || S_ISBLK (np->nn_stat.st_mode) + || fshelp_translated (&np->transbox))) + { + mach_port_t dirport; + + /* A callback function for short-circuited translators. + S_ISLNK and S_IFSOCK are handled elsewhere. */ + error_t short_circuited_callback1 (void *cookie1, void *cookie2, + uid_t *uid, gid_t *gid, + char **argz, size_t *argz_len) + { + struct node *np = cookie1; + error_t err; + + err = netfs_validate_stat (np, diruser->user); + if (err) + return err; + + switch (np->nn_stat.st_mode & S_IFMT) + { + case S_IFCHR: + case S_IFBLK: + asprintf (argz, "%s%c%d%c%d", + (S_ISCHR (np->nn_stat.st_mode) + ? _HURD_CHRDEV : _HURD_BLKDEV), + 0, major (np->nn_stat.st_rdev), + 0, minor (np->nn_stat.st_rdev)); + *argz_len = strlen (*argz) + 1; + *argz_len += strlen (*argz + *argz_len) + 1; + *argz_len += strlen (*argz + *argz_len) + 1; + break; + case S_IFIFO: + asprintf (argz, "%s", _HURD_FIFO); + *argz_len = strlen (*argz) + 1; + break; + default: + return ENOENT; + } + + *uid = np->nn_stat.st_uid; + *gid = np->nn_stat.st_gid; + + return 0; + } + + /* Create an unauthenticated port for DNP, and then + unlock it. */ + newpi = + netfs_make_protid (netfs_make_peropen (dnp, 0, diruser->po), + iohelp_create_iouser (make_idvec (), + make_idvec ())); + dirport = ports_get_right (newpi); + mach_port_insert_right (mach_task_self (), dirport, dirport, + MACH_MSG_TYPE_MAKE_SEND); + ports_port_deref (newpi); + + error = fshelp_fetch_root (&np->transbox, diruser->po, + dirport, + diruser->user, + lastcomp ? flags : 0, + ((np->nn_stat.st_mode & S_IPTRANS) + ? _netfs_translator_callback1 + : short_circuited_callback1), + _netfs_translator_callback2, + do_retry, retry_name, retry_port); + + if (error != ENOENT) + { + netfs_nrele (dnp); + netfs_nput (np); + *retry_port_type = MACH_MSG_TYPE_MOVE_SEND; + if (!lastcomp && !error) + { + strcat (retry_name, "/"); + strcat (retry_name, nextname); + } + return error; + } + + /* ENOENT means there was a hiccup, and the translator vanished + while NP was unlocked inside fshelp_fetch_root; continue as normal. */ + error = 0; + } + + if (S_ISLNK (np->nn_stat.st_mode) + && (!lastcomp + || mustbedir /* "foo/" must see that foo points to a dir */ + || !(flags & (O_NOLINK|O_NOTRANS)))) + { + size_t nextnamelen, newnamelen, linklen; + char *linkbuf; + + /* Handle symlink interpretation */ + if (nsymlinks++ > netfs_maxsymlinks) + { + error = ELOOP; + goto out; + } + + linklen = np->nn_stat.st_size; + + nextnamelen = nextname ? strlen (nextname) + 1 : 0; + newnamelen = nextnamelen + linklen + 1; + linkbuf = alloca (newnamelen); + + error = netfs_attempt_readlink (diruser->user, np, linkbuf); + if (error) + goto out; + + if (nextname) + { + linkbuf[linklen] = '/'; + bcopy (nextname, linkbuf + linklen + 1, + nextnamelen - 1); + } + linkbuf[nextnamelen + linklen] = '\0'; + + if (linkbuf[0] == '/') + { + /* Punt to the caller */ + *do_retry = FS_RETRY_MAGICAL; + *retry_port = MACH_PORT_NULL; + strcpy (retry_name, linkbuf); + goto out; + } + + filename = linkbuf; + if (lastcomp) + { + lastcomp = 0; + + /* Symlinks to nonexistent files aren't allowed to cause + creation, so clear the flag here. */ + create = 0; + } + netfs_nput (np); + mutex_lock (&dnp->lock); + np = 0; + } + else + { + /* Normal nodes here for next filename component */ + filename = nextname; + netfs_nrele (dnp); + + if (lastcomp) + dnp = 0; + else + { + dnp = np; + np = 0; + } + } + } + while (filename && *filename); + + /* At this point, NP is the node to return. */ + gotit: + + if (mustbedir) + { + netfs_validate_stat (np, diruser->user); + if (!S_ISDIR (np->nn_stat.st_mode)) + { + error = ENOTDIR; + goto out; + } + } + error = netfs_check_open_permissions (diruser->user, np, + flags, newnode); + if (error) + goto out; + + flags &= ~OPENONLY_STATE_MODES; + + newpi = netfs_make_protid (netfs_make_peropen (np, flags, diruser->po), + iohelp_dup_iouser (diruser->user)); + *retry_port = ports_get_right (newpi); + ports_port_deref (newpi); + + out: + if (np) + netfs_nput (np); + if (dnp) + netfs_nrele (dnp); + return error; +} |