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- /* -*- mode:c; c-file-style:"k&r"; c-basic-offset: 4; tab-width:4; indent-tabs-mode:nil; mode:auto-fill; fill-column:78; -*- */
- /* vim: set ts=4 sw=4 et tw=78 fo=cqt wm=0: */
- /* Copyright (C) 2014 OSCAR lab, Stony Brook University
- This file is part of Graphene Library OS.
- Graphene Library OS 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 3 of the
- License, or (at your option) any later version.
- Graphene Library OS 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, see <http://www.gnu.org/licenses/>. */
- /*
- * shim_namei.c
- *
- * This file contains codes for parsing a FS path and looking up in the
- * directory cache.
- * The source codes are imported from Linux kernel, but simplified according
- * to the characteristic of library OS.
- */
- #include <shim_internal.h>
- #include <shim_utils.h>
- #include <shim_thread.h>
- #include <shim_handle.h>
- #include <shim_fs.h>
- #include <shim_profile.h>
- #include <pal.h>
- #include <linux/stat.h>
- #include <linux/fcntl.h>
- #include <asm/fcntl.h>
- /* check permission of a dentry. If force is not set, permission
- is consider granted on invalid dentries */
- /* have dcache_lock acquired */
- int permission (struct shim_dentry * dent, int mask, bool force)
- {
- mode_t mode = 0;
- if (dent->state & DENTRY_ANCESTER)
- return 0;
- if (dent->state & DENTRY_NEGATIVE)
- return -ENOENT;
- if (!(dent->state & DENTRY_VALID) || dent->mode == NO_MODE) {
- if (!dent->fs || !dent->fs->d_ops || !dent->fs->d_ops->mode)
- return 0;
- /* the filesystem will decide the results when permission
- check isn't forced. If -ESKIPPED is returned, we assume
- the file/directory is accessible for now. */
- int err = dent->fs->d_ops->mode(dent, &mode, force);
- if (err == -ESKIPPED)
- return 0;
- if (err < 0)
- return err;
- if (dent->parent)
- dent->parent->nchildren++;
- dent->state |= DENTRY_VALID|DENTRY_RECENTLY;
- dent->mode = mode;
- } else {
- mode = dent->mode;
- }
- if (((mode >> 6) & mask & (MAY_READ|MAY_WRITE|MAY_EXEC)) == mask)
- return 0;
- return -EACCES;
- }
- static inline int __do_lookup_dentry (struct shim_dentry * dent, bool force)
- {
- int err = 0;
- if (!(dent->state & DENTRY_VALID) &&
- dent->fs && dent->fs->d_ops && dent->fs->d_ops->lookup) {
- if ((err = dent->fs->d_ops->lookup(dent, force)) < 0) {
- if (err == -ENOENT) {
- dent->state |= DENTRY_NEGATIVE;
- } else {
- if (err == -ESKIPPED)
- err = 0;
- return err;
- }
- }
- if (dent->parent)
- dent->parent->nchildren++;
- dent->state |= DENTRY_VALID|DENTRY_RECENTLY;
- }
- return 0;
- }
- /* looking up single dentry based on its parent and name */
- /* have dcache_lock acquired */
- int lookup_dentry (struct shim_dentry * parent, const char * name, int namelen,
- bool force, struct shim_dentry ** new)
- {
- struct shim_dentry * dent = NULL;
- int err = 0;
- HASHTYPE hash;
- dent = __lookup_dcache(parent, name, namelen, NULL, 0, &hash);
- if ((err = permission(parent, MAY_EXEC, false)) < 0) {
- if (dent)
- dent->state |= DENTRY_UNREACHABLE;
- goto out;
- }
- if (!dent) {
- dent = get_new_dentry(parent, name, namelen);
- if (!dent) {
- err = -ENOMEM;
- goto out;
- }
- if (parent->fs) {
- get_mount(parent->fs);
- dent->fs = parent->fs;
- }
- __set_parent_dentry(dent, parent);
- __add_dcache(dent, &hash);
- }
- err = __do_lookup_dentry(dent, force);
- dent->state |= DENTRY_REACHABLE;
- *new = dent;
- out:
- return err;
- }
- static void path_reacquire (struct lookup * look, struct shim_dentry * dent);
- /* looking up single dentry, but use struct lookup */
- /* have dcache_lock acquired */
- static int do_lookup (struct lookup * look, const char * name, int namelen,
- bool force)
- {
- int err = 0;
- struct shim_dentry * dent = NULL;
- if ((err = lookup_dentry(look->dentry, name, namelen,force, &dent)) < 0)
- goto fail;
- path_reacquire(look, dent);
- look->last = dentry_get_name(dent);
- look->last_type = LAST_NORM;
- fail:
- return err;
- }
- static int link_path_walk (const char * name, struct lookup * look);
- /* have dcache_lock acquired */
- void path_acquire (struct lookup * look)
- {
- if (look->dentry)
- get_dentry(look->dentry);
- if (look->mount)
- get_mount(look->mount);
- }
- /* have dcache_lock acquired */
- void path_release (struct lookup * look)
- {
- if (look->dentry)
- put_dentry(look->dentry);
- if (look->mount)
- put_mount(look->mount);
- }
- /* have dcache_lock acquired */
- static void path_reacquire (struct lookup * look, struct shim_dentry * dent)
- {
- struct shim_dentry * old_dent = look->dentry;
- struct shim_mount * old_mount = look->mount;
- if (dent && dent != old_dent) {
- get_dentry(dent);
- if (old_dent)
- put_dentry(old_dent);
- look->dentry = dent;
- }
- if (dent && dent->fs && dent->fs != old_mount) {
- get_mount(dent->fs);
- if (old_mount)
- put_mount(old_mount);
- look->mount = dent->fs;
- }
- }
- /* try follow a link where the dentry points to */
- /* have dcache_lock acquired */
- static inline int __do_follow_link (struct lookup * look)
- {
- int err = 0;
- struct shim_dentry * dent = look->dentry;
- assert(dent->state & DENTRY_ISLINK);
- assert(dent->fs->d_ops && dent->fs->d_ops->follow_link);
- struct shim_qstr this = QSTR_INIT;
- if ((err = dent->fs->d_ops->follow_link(dent, &this)) < 0)
- goto out;
- const char * link = qstrgetstr(&this);
- if (link) {
- /* symlink name starts with a slash, restart lookup at root */
- if (*link == '/') {
- struct shim_dentry * root = get_cur_thread()->root;
- path_reacquire(look, root);
- }
- look->flags |= LOOKUP_CONTINUE;
- /* now walk the whole link again */
- err = link_path_walk(link, look);
- }
- out:
- qstrfree(&this);
- return err;
- }
- /* follow links on a dentry until the last target */
- /* have dcache_lock acquired */
- static int follow_link (struct lookup * look)
- {
- int err = 0;
- int old_depth = look->depth;
- while (err >= 0 && look->dentry->state & DENTRY_ISLINK) {
- /* checks to contain link explosion */
- if (look->depth > 80) {
- err = -ELOOP;
- break;
- }
- look->depth++;
- err = __do_follow_link(look);
- }
- if (err < 0)
- look->depth = old_depth;
- return err;
- }
- /* follow a single dot-dot to the parent */
- /* have dcache_lock acquired */
- static int follow_dotdot (struct lookup * look)
- {
- struct shim_dentry * dent = look->dentry;
- struct shim_mount * mount = look->mount;
- struct shim_thread * cur_thread = get_cur_thread();
- while (1) {
- /* if it reaches the root of current filesystem,
- return immediately. */
- if (dent == cur_thread->root)
- break;
- if (dent != mount->root) {
- struct shim_dentry * parent = dent->parent;
- path_reacquire(look, parent);
- break;
- }
- struct shim_dentry * parent = mount->mount_point;
- path_reacquire(look, parent);
- dent = parent;
- mount = parent->fs;
- }
- return 0;
- }
- /* walk through a absolute path based on current lookup structure,
- across mount point, dot dot and symlinks */
- /* have dcache_lock acquired */
- static int link_path_walk (const char * name, struct lookup * look)
- {
- struct shim_dentry * dent = NULL;
- int err = 0;
- int lookup_flags = look->flags;
- /* remove all the slashes at the beginning */
- while (*name == '/')
- name++;
- if (!*name) {
- if (!(lookup_flags & LOOKUP_CONTINUE) &&
- (lookup_flags & LOOKUP_PARENT))
- path_reacquire(look, look->dentry->parent);
- goto out;
- }
- dent = look->dentry;
- lookup_flags |= LOOKUP_CONTINUE;
- while (*name) {
- const char * this_name = look->last = name;
- int namelen = -1;
- char c;
- do {
- namelen++;
- c = name[namelen];
- } while (c && (c != '/'));
- name += namelen;
- if (!c) {
- lookup_flags &= ~LOOKUP_CONTINUE;
- } else {
- while (*(++name) == '/');
- if (!*name) {
- lookup_flags |= LOOKUP_DIRECTORY;
- lookup_flags &= ~LOOKUP_CONTINUE;
- }
- }
- look->last_type = LAST_NORM;
- if (this_name[0] == '.')
- switch (namelen) {
- case 1:
- look->last_type = LAST_DOT;
- break;
- case 2:
- if (this_name[1] == '.')
- look->last_type = LAST_DOTDOT;
- /* fallthrough */
- default:
- break;
- }
- if (!(lookup_flags & LOOKUP_CONTINUE) &&
- (lookup_flags & LOOKUP_PARENT))
- goto out;
- switch (look->last_type) {
- case LAST_DOT:
- continue;
- case LAST_DOTDOT:
- err = follow_dotdot(look);
- if (err < 0)
- goto out;
- /* fallthrough */
- default:
- break;
- }
- if (look->last_type == LAST_NORM) {
- /* actual lookup */
- err = do_lookup(look, this_name, namelen, false);
- if (err < 0)
- goto out;
- }
- if ((look->dentry->state & DENTRY_ISLINK) &&
- (look->last_type != LAST_NORM || look->flags & LOOKUP_FOLLOW)) {
- err = follow_link(look);
- if (err < 0)
- goto out;
- }
- assert(!(look->dentry->state & DENTRY_MOUNTPOINT));
- dent = look->dentry;
- if (!(dent->state & DENTRY_VALID) &&
- (look->flags & LOOKUP_SYNC && !(lookup_flags & LOOKUP_CONTINUE)) &&
- look->mount && look->mount->d_ops &&
- look->mount->d_ops->lookup) {
- err = look->mount->d_ops->lookup(dent, 1);
- if (err < 0) {
- if (err == -ENOENT) {
- if (dent->state & DENTRY_VALID && dent->parent)
- dent->parent->nchildren--;
- dent->state |= DENTRY_NEGATIVE;
- err = 0;
- } else {
- goto out;
- }
- }
- if (!(dent->state & DENTRY_NEGATIVE) && dent->parent)
- dent->parent->nchildren++;
- dent->state |= DENTRY_VALID|DENTRY_RECENTLY;
- }
- if (dent->state & DENTRY_NEGATIVE) {
- if (lookup_flags & LOOKUP_CONTINUE) {
- if (!(dent->state & DENTRY_ANCESTER)) {
- err = -ENOENT;
- goto out;
- }
- } else {
- goto out;
- }
- }
- if (!(lookup_flags & LOOKUP_CONTINUE) &&
- (look->flags & LOOKUP_DIRECTORY) &&
- (dent->state & DENTRY_VALID) &&
- !(dent->state & DENTRY_ISDIRECTORY)) {
- err = -ENOTDIR;
- goto out;
- }
- }
- out:
- return err;
- }
- DEFINE_PROFILE_OCCURENCE(dcache_hit, dcache);
- DEFINE_PROFILE_OCCURENCE(dcache_miss, dcache);
- static int path_lookup_dcache (struct shim_dentry * start, const char * path,
- int flags,
- struct shim_dentry ** dent,
- struct shim_thread * cur_thread)
- {
- if (!start && cur_thread)
- start = *path == '/' ? cur_thread->root : cur_thread->cwd;
- const char * startpath = NULL;
- int startpathlen = 0;
- char * fullpath = __alloca(STR_SIZE);
- if (start) {
- startpath = dentry_get_path(start, true, &startpathlen);
- memcpy(fullpath, startpath, startpathlen);
- }
- char * name = fullpath + startpathlen;
- int namelen;
- if ((namelen = get_norm_path(path, name, 0, STR_SIZE - startpathlen)) < 0)
- return namelen;
- struct shim_dentry * found =
- __lookup_dcache(start, name, namelen,
- fullpath, startpathlen + namelen, NULL);
- if (found) {
- INC_PROFILE_OCCURENCE(dcache_hit);
- if (flags & LOOKUP_SYNC) {
- int ret = __do_lookup_dentry(found, true);
- if (ret < 0) {
- put_dentry(found);
- return ret;
- }
- }
- if (!(found->state & DENTRY_NEGATIVE) &&
- !(found->state & DENTRY_ISDIRECTORY) &&
- flags & LOOKUP_DIRECTORY) {
- put_dentry(found);
- return -ENOTDIR;
- }
- if (!(found->state & (DENTRY_REACHABLE|DENTRY_UNREACHABLE))) {
- put_dentry(found);
- found = NULL;
- }
- } else {
- INC_PROFILE_OCCURENCE(dcache_miss);
- }
- *dent = found;
- return 0;
- }
- /* have dcache_lock acquired */
- static int path_lookup_walk (struct shim_dentry * start,
- const char * name, int flags,
- struct lookup * look,
- struct shim_thread * cur_thread)
- {
- struct shim_dentry * dent = start;
- if (!dent) {
- if (cur_thread)
- lock(cur_thread->lock);
- dent = (*name == '/' ?
- (cur_thread ? cur_thread->root : NULL) :
- (cur_thread ? cur_thread->cwd : NULL)) ? : dentry_root;
- if (cur_thread)
- unlock(cur_thread->lock);
- }
- while (dent->state & DENTRY_MOUNTPOINT)
- dent = dent->mounted->root;
- look->dentry = dent;
- look->mount = dent->fs;
- look->last = dentry_get_name(dent);
- look->last_type = LAST_ROOT;
- look->flags = flags;
- look->depth = 0;
- path_acquire(look);
- return link_path_walk(name, look);
- }
- DEFINE_PROFILE_CATAGORY(path_lookup, dcache);
- DEFINE_PROFILE_INTERVAL(lookup_dcache_for_path_lookup, path_lookup);
- DEFINE_PROFILE_INTERVAL(lookup_walk_for_path_lookup, path_lookup);
- int __path_lookupat (struct shim_dentry * start, const char * path, int flags,
- struct shim_dentry ** dent)
- {
- struct shim_thread * cur_thread = get_cur_thread();
- struct shim_dentry * found = NULL;
- int ret = 0;
- struct lookup look;
- BEGIN_PROFILE_INTERVAL();
- ret = path_lookup_dcache(start, path, flags, &found, cur_thread);
- if (ret < 0)
- return ret;
- SAVE_PROFILE_INTERVAL(lookup_dcache_for_path_lookup);
- if (!found) {
- if ((ret = path_lookup_walk(start, path, flags, &look, cur_thread)) < 0)
- return ret;
- get_dentry(look.dentry);
- found = look.dentry;
- SAVE_PROFILE_INTERVAL(lookup_walk_for_path_lookup);
- if (flags & LOOKUP_SYNC) {
- if ((ret = __do_lookup_dentry(found, true)) < 0)
- goto out_if;
- }
- if (!(found->state & DENTRY_ISDIRECTORY) &&
- flags & LOOKUP_DIRECTORY) {
- ret = -ENOTDIR;
- goto out_if;
- }
- out_if:
- path_release(&look);
- }
- if (found) {
- if (!ret && dent)
- *dent = found;
- else
- put_dentry(found);
- }
- return 0;
- }
- /* if path_lookup succeed, the returned dentry is pop'ed */
- int path_lookupat (struct shim_dentry * start, const char * path, int flags,
- struct shim_dentry ** dent)
- {
- struct shim_thread * cur_thread = get_cur_thread();
- struct shim_dentry * found = NULL;
- int ret = 0;
- struct lookup look;
- lock(dcache_lock);
- BEGIN_PROFILE_INTERVAL();
- ret = path_lookup_dcache(start, path, flags, &found, cur_thread);
- if (ret < 0) {
- unlock(dcache_lock);
- return ret;
- }
- SAVE_PROFILE_INTERVAL(lookup_dcache_for_path_lookup);
- if (!found) {
- if ((ret = path_lookup_walk(start, path, flags, &look,
- cur_thread)) < 0)
- goto out;
- get_dentry(look.dentry);
- found = look.dentry;
- SAVE_PROFILE_INTERVAL(lookup_walk_for_path_lookup);
- if (flags & LOOKUP_SYNC) {
- if ((ret = __do_lookup_dentry(found, true)) < 0)
- goto out_release;
- }
- if (found->state & DENTRY_NEGATIVE &&
- !(flags & LOOKUP_CREATE)) {
- ret = -ENOENT;
- goto out_release;
- }
- if (!(found->state & DENTRY_NEGATIVE) &&
- !(found->state & DENTRY_ISDIRECTORY) &&
- flags & LOOKUP_DIRECTORY) {
- ret = -ENOTDIR;
- goto out_release;
- }
- out_release:
- path_release(&look);
- }
- if (found) {
- if (!ret && dent)
- *dent = found;
- else
- put_dentry(found);
- }
- out:
- unlock(dcache_lock);
- return ret;
- }
- static inline int __lookup_flags (int flags)
- {
- int retval = LOOKUP_FOLLOW;
- if (flags & O_NOFOLLOW)
- retval &= ~LOOKUP_FOLLOW;
- if ((flags & (O_CREAT|O_EXCL)) == (O_CREAT|O_EXCL))
- retval &= ~LOOKUP_FOLLOW;
- if (flags & O_DIRECTORY)
- retval |= LOOKUP_DIRECTORY;
- return retval;
- }
- int create_dentry (struct shim_handle * hdl, struct shim_dentry * dir,
- struct shim_dentry * dent, int flags, int mode)
- {
- int err = permission(dir, MAY_WRITE | MAY_EXEC, true);
- if (err)
- return err;
- if (!dir->fs->d_ops || !dir->fs->d_ops->creat)
- return -EACCES;
- err = dir->fs->d_ops->creat(hdl, dir, dent, flags, mode);
- if (err)
- return err;
- if (!hdl)
- return 0;
- set_handle_fs(hdl, dent->fs);
- get_dentry(dent);
- hdl->dentry = dent;
- hdl->flags = flags;
- int size;
- char *path = dentry_get_path(dent, true, &size);
- qstrsetstr(&hdl->path, path, size);
- return 0;
- }
- int create_directory (struct shim_dentry * dir, struct shim_dentry * dent,
- int mode)
- {
- int err = permission(dir, MAY_WRITE | MAY_EXEC, true);
- if (err)
- return err;
- if (!dir->fs->d_ops || !dir->fs->d_ops->mkdir)
- return -EACCES;
- return dir->fs->d_ops->mkdir(dir, dent, mode);
- }
- DEFINE_PROFILE_CATAGORY(open_namei, dcache);
- DEFINE_PROFILE_INTERVAL(path_lookup_dcache_for_open_namei, open_namei);
- DEFINE_PROFILE_INTERVAL(path_lookup_walk_for_open_namei, open_namei);
- DEFINE_PROFILE_INTERVAL(path_lookup_walk_2_for_open_namei, open_namei);
- DEFINE_PROFILE_INTERVAL(end_open_namei, open_namei);
- DEFINE_PROFILE_INTERVAL(open_namei_permission, open_namei);
- DEFINE_PROFILE_INTERVAL(open_namei_dir_open, open_namei);
- DEFINE_PROFILE_INTERVAL(open_namei_dentry_open, open_namei);
- DEFINE_PROFILE_INTERVAL(open_namei_lookup_2, open_namei);
- DEFINE_PROFILE_INTERVAL(open_namei_path_reacquire, open_namei);
- DEFINE_PROFILE_INTERVAL(open_namei_create_dir, open_namei);
- DEFINE_PROFILE_INTERVAL(open_namei_create_dentry, open_namei);
- int open_namei (struct shim_handle * hdl, struct shim_dentry * start,
- const char * path, int flags, int mode,
- struct shim_dentry ** dent)
- {
- struct shim_thread * cur_thread = get_cur_thread();
- struct lookup look = { .dentry = NULL, .mount = NULL };
- struct shim_dentry * dir = NULL;
- int err = 0;
- int acc_mode = ACC_MODE(flags & O_ACCMODE);
- int lookup_flags = __lookup_flags(flags);
- #ifdef MAY_APPEND
- if (flags & O_APPEND)
- acc_mode |= MAY_APPEND;
- #endif
- BEGIN_PROFILE_INTERVAL();
- lock(dcache_lock);
- #if 0
- err = path_lookup_dcache(start, path, lookup_flags|LOOKUP_OPEN,
- &look.dentry, cur_thread);
- if (err >= 0 && look.dentry) {
- look.mount = look.dentry->fs;
- if (look.mount)
- get_mount(look.mount);
- }
- SAVE_PROFILE_INTERVAL(path_lookup_dcache_for_open_namei);
- if (err < 0) {
- unlock(dcache_lock);
- SAVE_PROFILE_INTERVAL(end_open_namei);
- return err;
- }
- #endif
- if (look.dentry) {
- if (look.dentry->state & DENTRY_NEGATIVE) {
- if (!(flags & O_CREAT)) {
- err = -ENOENT;
- goto exit;
- }
- dir = look.dentry->parent;
- get_dentry(dir);
- goto do_creat;
- }
- if (flags & O_EXCL) {
- err = -EEXIST;
- goto exit;
- }
- goto do_open_locked;
- }
- /* no create, just look it up. */
- if (!(flags & O_CREAT)) {
- err = path_lookup_walk(start, path, lookup_flags|LOOKUP_OPEN,
- &look, cur_thread);
- SAVE_PROFILE_INTERVAL(path_lookup_walk_for_open_namei);
- if (err) {
- debug("path_lookup error in open_namei\n");
- goto exit;
- }
- do_open_locked:
- unlock(dcache_lock);
- do_open:
- if ((err = permission(look.dentry, acc_mode, true)) < 0)
- goto exit;
- SAVE_PROFILE_INTERVAL(open_namei_permission);
- if (hdl) {
- if (look.dentry->state & DENTRY_ISDIRECTORY) {
- if ((err = directory_open(hdl, look.dentry, flags)) < 0)
- goto exit;
- SAVE_PROFILE_INTERVAL(open_namei_dir_open);
- } else {
- err = -ENOTDIR;
- if (flags & O_DIRECTORY) {
- debug("%s is not a directory\n",
- dentry_get_path(look.dentry, true, NULL));
- goto exit;
- }
- if ((err = dentry_open(hdl, look.dentry, flags)) < 0)
- goto exit;
- SAVE_PROFILE_INTERVAL(open_namei_dentry_open);
- }
- }
- goto done;
- }
- /* create, so we need the parent */
- err = path_lookup_walk(start, path, LOOKUP_PARENT|LOOKUP_OPEN|LOOKUP_CREATE,
- &look, cur_thread);
- SAVE_PROFILE_INTERVAL(path_lookup_walk_2_for_open_namei);
- if (err < 0 || look.last_type != LAST_NORM)
- goto exit;
- struct shim_dentry * new = NULL;
- dir = look.dentry;
- get_dentry(dir);
- err = lookup_dentry(dir, look.last, strlen(look.last), true, &new);
- SAVE_PROFILE_INTERVAL(open_namei_lookup_2);
- if (err < 0 && (err != -ENOENT || !new))
- goto exit;
- path_reacquire(&look, new);
- SAVE_PROFILE_INTERVAL(open_namei_path_reacquire);
- do_creat:
- assert(dir);
- unlock(dcache_lock);
- /* negative dentry */
- if (look.dentry->state & DENTRY_NEGATIVE) {
- if (flags & O_DIRECTORY) {
- if ((err = create_directory(dir, look.dentry, mode)) < 0) {
- debug("error: create directory in open_namei\n");
- goto exit;
- }
- SAVE_PROFILE_INTERVAL(open_namei_create_dir);
- look.dentry->state |= DENTRY_ISDIRECTORY;
- } else {
- if ((err = create_dentry(hdl, dir, look.dentry, flags,
- mode)) < 0) {
- debug("error: create file in open_namei\n");
- goto exit;
- }
- SAVE_PROFILE_INTERVAL(open_namei_create_dentry);
- }
- look.dentry->state &= ~DENTRY_NEGATIVE;
- if (hdl && (flags & O_DIRECTORY))
- goto do_open;
- else
- goto done;
- }
- /* existing dentry */
- if (flags & O_EXCL) {
- err = -EEXIST;
- debug("error: existing dentry with O_EXCL\n");
- goto exit;
- }
- if (look.dentry->state & DENTRY_ISLINK) {
- if (flags & O_NOFOLLOW) {
- err = -ELOOP;
- debug("error: linked dentry with O_NOFOLLOW\n");
- goto exit;
- }
- if ((err = follow_link(&look)) < 0)
- goto exit;
- }
- assert(!(look.dentry->state & DENTRY_MOUNTPOINT));
- goto do_open;
- done:
- if (dent) {
- get_dentry(look.dentry);
- *dent = look.dentry;
- }
- path_release(&look);
- if (locked(dcache_lock))
- unlock(dcache_lock);
- SAVE_PROFILE_INTERVAL(end_open_namei);
- return 0;
- exit:
- path_release(&look);
- if (dir)
- put_dentry(dir);
- if (locked(dcache_lock))
- unlock(dcache_lock);
- SAVE_PROFILE_INTERVAL(end_open_namei);
- return err;
- }
- DEFINE_PROFILE_CATAGORY(dentry_open, dcache);
- DEFINE_PROFILE_INTERVAL(dentry_open_open, dentry_open);
- DEFINE_PROFILE_INTERVAL(dentry_open_truncate, dentry_open);
- DEFINE_PROFILE_INTERVAL(dentry_open_set_path, dentry_open);
- int dentry_open (struct shim_handle * hdl, struct shim_dentry * dent,
- int flags)
- {
- int ret = 0;
- struct shim_mount * fs = dent->fs;
- BEGIN_PROFILE_INTERVAL();
- if (!fs->d_ops || !fs->d_ops->open) {
- ret = -EACCES;
- goto out;
- }
- if ((ret = fs->d_ops->open(hdl, dent, flags)) < 0)
- goto out;
- SAVE_PROFILE_INTERVAL(dentry_open_open);
- set_handle_fs(hdl, fs);
- get_dentry(dent);
- hdl->dentry = dent;
- hdl->flags = flags;
- /* truncate the file if O_TRUNC is given */
- if (ret >= 0 && (flags & O_TRUNC) && fs->fs_ops->truncate) {
- ret = fs->fs_ops->truncate(hdl, 0);
- SAVE_PROFILE_INTERVAL(dentry_open_truncate);
- }
- if (ret < 0)
- goto out;
- int size;
- char *path = dentry_get_path(dent, true, &size);
- qstrsetstr(&hdl->path, path, size);
- SAVE_PROFILE_INTERVAL(dentry_open_set_path);
- out:
- return ret;
- }
- static inline void set_dirent_type (mode_t * type, int d_type)
- {
- switch (d_type) {
- case LINUX_DT_FIFO:
- *type = S_IFIFO;
- return;
- case LINUX_DT_CHR:
- *type = S_IFCHR;
- return;
- case LINUX_DT_BLK:
- *type = S_IFBLK;
- return;
- case LINUX_DT_REG:
- *type = S_IFREG;
- return;
- case LINUX_DT_LNK:
- *type = S_IFLNK;
- return;
- case LINUX_DT_SOCK:
- *type = S_IFSOCK;
- return;
- default:
- *type = 0;
- return;
- }
- }
- int directory_open (struct shim_handle * hdl, struct shim_dentry * dent,
- int flags)
- {
- struct shim_mount * fs = dent->fs;
- int ret = 0;
- if (!fs->d_ops || !fs->d_ops->readdir) {
- ret = -EACCES;
- goto out;
- }
- int size;
- const char * path = dentry_get_path(dent, true, &size);
- lock(dcache_lock);
- if (!(dent->state & DENTRY_LISTED)) {
- struct shim_dirent * dirent = NULL;
- if ((ret = fs->d_ops->readdir(dent, &dirent)) < 0 || !dirent)
- goto done_read;
- struct shim_dirent * d = dirent;
- for ( ; d ; d = d->next) {
- debug("read %s from %s\n", d->name, path);
- struct shim_dentry * child;
- if ((ret = lookup_dentry(dent, d->name, strlen(d->name), false,
- &child)) < 0)
- goto done_read;
- if (child->state & DENTRY_NEGATIVE)
- continue;
- if (!(child->state & DENTRY_VALID)) {
- set_dirent_type(&child->type, d->type);
- child->state |= DENTRY_VALID|DENTRY_RECENTLY;
- }
- child->ino = d->ino;
- }
- free(dirent);
- dent->state |= DENTRY_LISTED;
- }
- done_read:
- unlock(dcache_lock);
- struct shim_dentry ** children = NULL;
- if (dent->state & DENTRY_LISTED) {
- int nchildren = dent->nchildren, count = 0;
- struct shim_dentry * child;
- children = malloc(sizeof(struct shim_dentry *) * (nchildren + 1));
- listp_for_each_entry(child, &dent->children, siblings) {
- if (count >= nchildren)
- break;
- struct shim_dentry * c = child;
- while (c->state & DENTRY_MOUNTPOINT)
- c = c->mounted->root;
- if (c->state & DENTRY_VALID) {
- get_dentry(c);
- children[count++] = c;
- }
- }
- children[count] = NULL;
- }
- qstrsetstr(&hdl->path, path, size);
- hdl->type = TYPE_DIR;
- hdl->fs = fs;
- memcpy(hdl->fs_type, fs->type, sizeof(fs->type));
- hdl->dentry = dent;
- hdl->flags = flags;
- get_dentry(dent);
- hdl->info.dir.dot = dent;
- if (dent->parent) {
- get_dentry(dent->parent);
- hdl->info.dir.dotdot = dent->parent;
- }
- hdl->info.dir.buf = children;
- hdl->info.dir.ptr = children;
- out:
- return ret;
- }
- int path_startat (int dfd, struct shim_dentry ** dir)
- {
- if (dfd == AT_FDCWD) {
- struct shim_thread * cur = get_cur_thread();
- get_dentry(cur->cwd);
- *dir = cur->cwd;
- return 0;
- } else if (dfd < 0) {
- return -EBADF;
- } else {
- struct shim_handle * hdl = get_fd_handle(dfd, NULL, NULL);
- if (!hdl)
- return -EBADF;
- if (hdl->type != TYPE_DIR) {
- put_handle(hdl);
- return -ENOTDIR;
- }
- get_dentry(hdl->dentry);
- put_handle(hdl);
- *dir = hdl->dentry;
- return 0;
- }
- }
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