02dc6498da
Change-Id: Ic4d2a616ebc986c4b405b6b9ee0bd7c3b59e81d2
314 lines
7.6 KiB
C
314 lines
7.6 KiB
C
/* VTreeFS - path.c - by Alen Stojanov and David van Moolenbroek */
|
|
|
|
#include "inc.h"
|
|
|
|
/*===========================================================================*
|
|
* access_as_dir *
|
|
*===========================================================================*/
|
|
static int access_as_dir(struct inode *node, vfs_ucred_t *ucred)
|
|
{
|
|
/* Check whether the given inode may be accessed as directory.
|
|
* Return OK or an appropriate error code.
|
|
*/
|
|
pmode_t mask;
|
|
int i;
|
|
|
|
/* The inode must be a directory to begin with. */
|
|
if (!S_ISDIR(node->i_stat.mode)) return ENOTDIR;
|
|
|
|
/* The caller must have search access to the directory.
|
|
* Root always does.
|
|
*/
|
|
if (ucred->vu_uid == SUPER_USER) return OK;
|
|
|
|
if (ucred->vu_uid == node->i_stat.uid) mask = S_IXUSR;
|
|
else if (ucred->vu_gid == node->i_stat.gid) mask = S_IXGRP;
|
|
else {
|
|
mask = S_IXOTH;
|
|
|
|
for (i = 0; i < ucred->vu_ngroups; i++) {
|
|
if (ucred->vu_sgroups[i] == node->i_stat.gid) {
|
|
mask = S_IXGRP;
|
|
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
return (node->i_stat.mode & mask) ? OK : EACCES;
|
|
}
|
|
|
|
/*===========================================================================*
|
|
* next_name *
|
|
*===========================================================================*/
|
|
static int next_name(char **ptr, char **start, char name[PNAME_MAX+1])
|
|
{
|
|
/* Get the next path component from a path.
|
|
*/
|
|
char *p;
|
|
int i;
|
|
|
|
for (p = *ptr; *p == '/'; p++);
|
|
|
|
*start = p;
|
|
|
|
if (*p) {
|
|
for (i = 0; *p && *p != '/' && i <= PNAME_MAX; p++, i++)
|
|
name[i] = *p;
|
|
|
|
if (i > PNAME_MAX)
|
|
return ENAMETOOLONG;
|
|
|
|
name[i] = 0;
|
|
} else {
|
|
strcpy(name, ".");
|
|
}
|
|
|
|
*ptr = p;
|
|
return OK;
|
|
}
|
|
|
|
/*===========================================================================*
|
|
* go_up *
|
|
*===========================================================================*/
|
|
static int go_up(struct inode *node, struct inode **parent)
|
|
{
|
|
/* Given a directory inode, progress into the parent directory.
|
|
*/
|
|
|
|
*parent = get_parent_inode(node);
|
|
|
|
/* Trapped in a deleted directory? Should not be possible. */
|
|
if (*parent == NULL)
|
|
return ENOENT;
|
|
|
|
ref_inode(*parent);
|
|
|
|
return OK;
|
|
}
|
|
|
|
/*===========================================================================*
|
|
* go_down *
|
|
*===========================================================================*/
|
|
static int go_down(struct inode *parent, char *name, struct inode **child)
|
|
{
|
|
/* Given a directory inode and a name, progress into a directory entry.
|
|
*/
|
|
int r;
|
|
|
|
/* Call the lookup hook, if present, before doing the actual lookup. */
|
|
if (!is_inode_deleted(parent) && vtreefs_hooks->lookup_hook != NULL) {
|
|
r = vtreefs_hooks->lookup_hook(parent, name,
|
|
get_inode_cbdata(parent));
|
|
if (r != OK) return r;
|
|
}
|
|
|
|
if ((*child = get_inode_by_name(parent, name)) == NULL)
|
|
return ENOENT;
|
|
|
|
ref_inode(*child);
|
|
|
|
return OK;
|
|
}
|
|
|
|
/*===========================================================================*
|
|
* resolve_link *
|
|
*===========================================================================*/
|
|
static int resolve_link(struct inode *node, char pptr[PATH_MAX], char *tail)
|
|
{
|
|
/* Given a symbolic link, resolve and return the contents of the link.
|
|
*/
|
|
char path[PATH_MAX];
|
|
size_t len;
|
|
int r;
|
|
|
|
assert(vtreefs_hooks->rdlink_hook != NULL);
|
|
assert(!is_inode_deleted(node));
|
|
|
|
r = vtreefs_hooks->rdlink_hook(node, path, sizeof(path),
|
|
get_inode_cbdata(node));
|
|
if (r != OK) return r;
|
|
|
|
len = strlen(path);
|
|
assert(len > 0 && len < sizeof(path));
|
|
|
|
if (len + strlen(tail) >= sizeof(path))
|
|
return ENAMETOOLONG;
|
|
|
|
strlcat(path, tail, sizeof(path));
|
|
|
|
strlcpy(pptr, path, PATH_MAX);
|
|
|
|
return OK;
|
|
}
|
|
|
|
/*===========================================================================*
|
|
* fs_lookup *
|
|
*===========================================================================*/
|
|
int fs_lookup(void)
|
|
{
|
|
/* Resolve a path string to an inode.
|
|
*/
|
|
ino_t dir_ino_nr, root_ino_nr;
|
|
struct inode *cur_ino, *next_ino, *root_ino;
|
|
char path[PATH_MAX], name[PNAME_MAX+1];
|
|
char *ptr, *last;
|
|
vfs_ucred_t ucred;
|
|
size_t len;
|
|
int r, r2, symloop;
|
|
|
|
dir_ino_nr = fs_m_in.m_vfs_fs_lookup.dir_ino;
|
|
root_ino_nr = fs_m_in.m_vfs_fs_lookup.root_ino;
|
|
len = fs_m_in.m_vfs_fs_lookup.path_len;
|
|
|
|
/* Fetch the path name. */
|
|
if (len < 1 || len > PATH_MAX)
|
|
return EINVAL;
|
|
|
|
r = sys_safecopyfrom(fs_m_in.m_source,
|
|
fs_m_in.m_vfs_fs_lookup.grant_path, 0, (vir_bytes) path,
|
|
(phys_bytes) len);
|
|
if (r != OK) return r;
|
|
|
|
if (path[len-1] != 0) return EINVAL;
|
|
|
|
/* Fetch the caller's credentials. */
|
|
if (fs_m_in.m_vfs_fs_lookup.flags & PATH_GET_UCRED) {
|
|
assert(fs_m_in.m_vfs_fs_lookup.ucred_size == sizeof(ucred));
|
|
|
|
r = sys_safecopyfrom(fs_m_in.m_source,
|
|
fs_m_in.m_vfs_fs_lookup.grant_ucred, 0,
|
|
(vir_bytes) &ucred, fs_m_in.m_vfs_fs_lookup.ucred_size);
|
|
|
|
if (r != OK)
|
|
return r;
|
|
}
|
|
else {
|
|
ucred.vu_uid = fs_m_in.m_vfs_fs_lookup.uid;
|
|
ucred.vu_gid = fs_m_in.m_vfs_fs_lookup.gid;
|
|
ucred.vu_ngroups = 0;
|
|
}
|
|
|
|
/* Start the actual lookup. */
|
|
if ((cur_ino = get_inode(dir_ino_nr)) == NULL)
|
|
return EINVAL;
|
|
|
|
/* Chroot'ed environment? */
|
|
if (root_ino_nr > 0)
|
|
root_ino = find_inode(root_ino_nr);
|
|
else
|
|
root_ino = NULL;
|
|
|
|
symloop = 0;
|
|
|
|
for (ptr = last = path; ptr[0] != 0; ) {
|
|
/* There is more path to process. That means that the current
|
|
* file is now being accessed as a directory. Check type and
|
|
* permissions.
|
|
*/
|
|
if ((r = access_as_dir(cur_ino, &ucred)) != OK)
|
|
break;
|
|
|
|
/* Get the next path component. The result is a non-empty
|
|
* string.
|
|
*/
|
|
if ((r = next_name(&ptr, &last, name)) != OK)
|
|
break;
|
|
|
|
if (!strcmp(name, ".") ||
|
|
(cur_ino == root_ino && !strcmp(name, "..")))
|
|
continue;
|
|
|
|
if (!strcmp(name, "..")) {
|
|
if (cur_ino == get_root_inode())
|
|
r = ELEAVEMOUNT;
|
|
else
|
|
r = go_up(cur_ino, &next_ino);
|
|
} else {
|
|
r = go_down(cur_ino, name, &next_ino);
|
|
|
|
/* Perform symlink resolution if we have to. */
|
|
if (r == OK && S_ISLNK(next_ino->i_stat.mode) &&
|
|
(ptr[0] != '\0' ||
|
|
!(fs_m_in.m_vfs_fs_lookup.flags & PATH_RET_SYMLINK))) {
|
|
|
|
if (++symloop == _POSIX_SYMLOOP_MAX) {
|
|
put_inode(next_ino);
|
|
|
|
r = ELOOP;
|
|
|
|
break;
|
|
}
|
|
|
|
/* Resolve the symlink, and append the
|
|
* remaining unresolved part of the path.
|
|
*/
|
|
r = resolve_link(next_ino, path, ptr);
|
|
|
|
put_inode(next_ino);
|
|
|
|
if (r != OK)
|
|
break;
|
|
|
|
/* If the symlink is absolute, return it to
|
|
* VFS.
|
|
*/
|
|
if (path[0] == '/') {
|
|
r = ESYMLINK;
|
|
last = path;
|
|
|
|
break;
|
|
}
|
|
|
|
ptr = path;
|
|
continue;
|
|
}
|
|
}
|
|
|
|
if (r != OK)
|
|
break;
|
|
|
|
/* We have found a new file. Continue from this file. */
|
|
assert(next_ino != NULL);
|
|
|
|
put_inode(cur_ino);
|
|
|
|
cur_ino = next_ino;
|
|
}
|
|
|
|
/* If an error occurred, close the file and return error information.
|
|
*/
|
|
if (r != OK) {
|
|
put_inode(cur_ino);
|
|
|
|
/* We'd need support for this here. */
|
|
assert(r != EENTERMOUNT);
|
|
|
|
/* Copy back the path if we resolved at least one symlink. */
|
|
if (symloop > 0 && (r == ELEAVEMOUNT || r == ESYMLINK)) {
|
|
r2 = sys_safecopyto(fs_m_in.m_source,
|
|
fs_m_in.m_vfs_fs_lookup.grant_path, 0,
|
|
(vir_bytes) path, strlen(path) + 1);
|
|
|
|
if (r2 != OK)
|
|
r = r2;
|
|
}
|
|
|
|
if (r == ELEAVEMOUNT || r == ESYMLINK) {
|
|
fs_m_out.m_fs_vfs_lookup.offset = (int) (last - path);
|
|
fs_m_out.m_fs_vfs_lookup.symloop = symloop;
|
|
}
|
|
|
|
return r;
|
|
}
|
|
|
|
/* On success, leave the resulting file open and return its details. */
|
|
fs_m_out.m_fs_vfs_lookup.inode = get_inode_number(cur_ino);
|
|
fs_m_out.m_fs_vfs_lookup.mode = cur_ino->i_stat.mode;
|
|
fs_m_out.m_fs_vfs_lookup.file_size = cur_ino->i_stat.size;
|
|
fs_m_out.m_fs_vfs_lookup.uid = cur_ino->i_stat.uid;
|
|
fs_m_out.m_fs_vfs_lookup.gid = cur_ino->i_stat.gid;
|
|
fs_m_out.m_fs_vfs_lookup.device = cur_ino->i_stat.dev;
|
|
|
|
return OK;
|
|
}
|