If the provided path was only a single component (i.e., without slashes), then last_dir would return early and skip the symlink detection (i.e., check whether the path ends in a symlink and resolve that first before returning). This bug triggered an assert in open which expects that an advance after an last_dir (with VMNT_WRITE lock) does not yield another vmnt lock.
791 lines
22 KiB
C
791 lines
22 KiB
C
/* lookup() is the main routine that controls the path name lookup. It
|
|
* handles mountpoints and symbolic links. The actual lookup requests
|
|
* are sent through the req_lookup wrapper function.
|
|
*/
|
|
|
|
#include "fs.h"
|
|
#include <string.h>
|
|
#include <minix/callnr.h>
|
|
#include <minix/com.h>
|
|
#include <minix/keymap.h>
|
|
#include <minix/const.h>
|
|
#include <minix/endpoint.h>
|
|
#include <unistd.h>
|
|
#include <assert.h>
|
|
#include <minix/vfsif.h>
|
|
#include <sys/stat.h>
|
|
#include <sys/un.h>
|
|
#include <dirent.h>
|
|
#include "threads.h"
|
|
#include "vmnt.h"
|
|
#include "vnode.h"
|
|
#include "path.h"
|
|
#include "fproc.h"
|
|
#include "param.h"
|
|
|
|
/* Set to following define to 1 if you really want to use the POSIX definition
|
|
* (IEEE Std 1003.1, 2004) of pathname resolution. POSIX requires pathnames
|
|
* with a traling slash (and that do not entirely consist of slash characters)
|
|
* to be treated as if a single dot is appended. This means that for example
|
|
* mkdir("dir/", ...) and rmdir("dir/") will fail because the call tries to
|
|
* create or remove the directory '.'. Historically, Unix systems just ignore
|
|
* trailing slashes.
|
|
*/
|
|
#define DO_POSIX_PATHNAME_RES 0
|
|
|
|
FORWARD _PROTOTYPE( int lookup, (struct vnode *dirp, struct lookup *resolve,
|
|
node_details_t *node, struct fproc *rfp));
|
|
FORWARD _PROTOTYPE( int check_perms, (endpoint_t ep, cp_grant_id_t io_gr,
|
|
size_t pathlen) );
|
|
|
|
/*===========================================================================*
|
|
* advance *
|
|
*===========================================================================*/
|
|
PUBLIC struct vnode *advance(dirp, resolve, rfp)
|
|
struct vnode *dirp;
|
|
struct lookup *resolve;
|
|
struct fproc *rfp;
|
|
{
|
|
/* Resolve a path name starting at dirp to a vnode. */
|
|
int r;
|
|
int do_downgrade = 1;
|
|
struct vnode *new_vp, *vp;
|
|
struct vmnt *vmp;
|
|
struct node_details res = {0,0,0,0,0,0,0};
|
|
tll_access_t initial_locktype;
|
|
|
|
assert(dirp);
|
|
assert(resolve->l_vnode_lock != TLL_NONE);
|
|
assert(resolve->l_vmnt_lock != TLL_NONE);
|
|
|
|
if (resolve->l_vnode_lock == VNODE_READ)
|
|
initial_locktype = VNODE_OPCL;
|
|
else
|
|
initial_locktype = resolve->l_vnode_lock;
|
|
|
|
/* Get a free vnode and lock it */
|
|
if ((new_vp = get_free_vnode()) == NULL) return(NULL);
|
|
lock_vnode(new_vp, initial_locktype);
|
|
|
|
/* Lookup vnode belonging to the file. */
|
|
if ((r = lookup(dirp, resolve, &res, rfp)) != OK) {
|
|
err_code = r;
|
|
unlock_vnode(new_vp);
|
|
return(NULL);
|
|
}
|
|
|
|
/* Check whether we already have a vnode for that file */
|
|
if ((vp = find_vnode(res.fs_e, res.inode_nr)) != NULL) {
|
|
unlock_vnode(new_vp); /* Don't need this anymore */
|
|
do_downgrade = (lock_vnode(vp, initial_locktype) != EBUSY);
|
|
|
|
/* Unfortunately, by the time we get the lock, another thread might've
|
|
* rid of the vnode (e.g., find_vnode found the vnode while a
|
|
* req_putnode was being processed). */
|
|
if (vp->v_ref_count == 0) { /* vnode vanished! */
|
|
/* As the lookup before increased the usage counters in the FS,
|
|
* we can simply set the usage counters to 1 and proceed as
|
|
* normal, because the putnode resulted in a use count of 1 in
|
|
* the FS. Other data is still valid, because the vnode was
|
|
* marked as pending lock, so get_free_vnode hasn't
|
|
* reinitialized the vnode yet. */
|
|
vp->v_fs_count = 1;
|
|
if (vp->v_mapfs_e != NONE) vp->v_mapfs_count = 1;
|
|
} else {
|
|
vp->v_fs_count++; /* We got a reference from the FS */
|
|
}
|
|
|
|
} else {
|
|
/* Vnode not found, fill in the free vnode's fields */
|
|
|
|
new_vp->v_fs_e = res.fs_e;
|
|
new_vp->v_inode_nr = res.inode_nr;
|
|
new_vp->v_mode = res.fmode;
|
|
new_vp->v_size = res.fsize;
|
|
new_vp->v_uid = res.uid;
|
|
new_vp->v_gid = res.gid;
|
|
new_vp->v_sdev = res.dev;
|
|
|
|
if( (vmp = find_vmnt(new_vp->v_fs_e)) == NULL)
|
|
panic("advance: vmnt not found");
|
|
|
|
new_vp->v_vmnt = vmp;
|
|
new_vp->v_dev = vmp->m_dev;
|
|
new_vp->v_fs_count = 1;
|
|
|
|
vp = new_vp;
|
|
}
|
|
|
|
dup_vnode(vp);
|
|
if (do_downgrade) {
|
|
/* Only downgrade a lock if we managed to lock it in the first place */
|
|
*(resolve->l_vnode) = vp;
|
|
|
|
if (initial_locktype != resolve->l_vnode_lock)
|
|
tll_downgrade(&vp->v_lock);
|
|
|
|
#if LOCK_DEBUG
|
|
if (resolve->l_vnode_lock == VNODE_READ)
|
|
fp->fp_vp_rdlocks++;
|
|
#endif
|
|
}
|
|
|
|
return(vp);
|
|
}
|
|
|
|
/*===========================================================================*
|
|
* eat_path *
|
|
*===========================================================================*/
|
|
PUBLIC struct vnode *eat_path(resolve, rfp)
|
|
struct lookup *resolve;
|
|
struct fproc *rfp;
|
|
{
|
|
/* Resolve path to a vnode. advance does the actual work. */
|
|
struct vnode *start_dir;
|
|
|
|
start_dir = (resolve->l_path[0] == '/' ? rfp->fp_rd : rfp->fp_wd);
|
|
return advance(start_dir, resolve, rfp);
|
|
}
|
|
|
|
/*===========================================================================*
|
|
* last_dir *
|
|
*===========================================================================*/
|
|
PUBLIC struct vnode *last_dir(resolve, rfp)
|
|
struct lookup *resolve;
|
|
struct fproc *rfp;
|
|
{
|
|
/* Parse a path, as far as the last directory, fetch the vnode
|
|
* for the last directory into the vnode table, and return a pointer to the
|
|
* vnode. In addition, return the final component of the path in 'string'. If
|
|
* the last directory can't be opened, return NULL and the reason for
|
|
* failure in 'err_code'. We can't parse component by component as that would
|
|
* be too expensive. Alternatively, we cut off the last component of the path,
|
|
* and parse the path up to the penultimate component.
|
|
*/
|
|
|
|
size_t len;
|
|
char *cp;
|
|
char dir_entry[NAME_MAX+1];
|
|
struct vnode *start_dir, *res_vp, *sym_vp, *loop_start;
|
|
struct vmnt *sym_vmp = NULL;
|
|
int r, symloop = 0, ret_on_symlink = 0;
|
|
struct lookup symlink;
|
|
|
|
*resolve->l_vnode = NULL;
|
|
*resolve->l_vmp = NULL;
|
|
loop_start = NULL;
|
|
sym_vp = NULL;
|
|
|
|
ret_on_symlink = !!(resolve->l_flags & PATH_RET_SYMLINK);
|
|
|
|
do {
|
|
/* Is the path absolute or relative? Initialize 'start_dir'
|
|
* accordingly. Use loop_start in case we're looping.
|
|
*/
|
|
if (loop_start != NULL)
|
|
start_dir = loop_start;
|
|
else
|
|
start_dir = (resolve->l_path[0] == '/' ? rfp->fp_rd:rfp->fp_wd);
|
|
|
|
len = strlen(resolve->l_path);
|
|
|
|
/* If path is empty, return ENOENT. */
|
|
if (len == 0) {
|
|
err_code = ENOENT;
|
|
res_vp = NULL;
|
|
break;
|
|
}
|
|
|
|
#if !DO_POSIX_PATHNAME_RES
|
|
/* Remove trailing slashes */
|
|
while (len > 1 && resolve->l_path[len-1] == '/') {
|
|
len--;
|
|
resolve->l_path[len]= '\0';
|
|
}
|
|
#endif
|
|
|
|
cp = strrchr(resolve->l_path, '/');
|
|
if (cp == NULL) {
|
|
/* Just an entry in the current working directory. Prepend
|
|
* "./" in front of the path and resolve it.
|
|
*/
|
|
strncpy(dir_entry, resolve->l_path, NAME_MAX);
|
|
dir_entry[NAME_MAX] = '\0';
|
|
resolve->l_path[0] = '.';
|
|
resolve->l_path[1] = '\0';
|
|
} else if (cp[1] == '\0') {
|
|
/* Path ends in a slash. The directory entry is '.' */
|
|
strcpy(dir_entry, ".");
|
|
} else {
|
|
/* A path name for the directory and a directory entry */
|
|
strncpy(dir_entry, cp+1, NAME_MAX);
|
|
cp[1] = '\0';
|
|
dir_entry[NAME_MAX] = '\0';
|
|
}
|
|
|
|
/* Remove trailing slashes */
|
|
while (cp > resolve->l_path && cp[0] == '/') {
|
|
cp[0]= '\0';
|
|
cp--;
|
|
}
|
|
|
|
/* Resolve up to and including the last directory of the path. Turn off
|
|
* PATH_RET_SYMLINK, because we do want to follow the symlink in this
|
|
* case. That is, the flag is meant for the actual filename of the path,
|
|
* not the last directory.
|
|
*/
|
|
resolve->l_flags &= ~PATH_RET_SYMLINK;
|
|
if ((res_vp = advance(start_dir, resolve, rfp)) == NULL) {
|
|
break;
|
|
}
|
|
|
|
/* If the directory entry is not a symlink we're done now. If it is a
|
|
* symlink, then we're not at the last directory, yet. */
|
|
|
|
/* Copy the directory entry back to user_fullpath */
|
|
strncpy(resolve->l_path, dir_entry, NAME_MAX + 1);
|
|
|
|
/* Look up the directory entry, but do not follow the symlink when it
|
|
* is one.
|
|
*/
|
|
lookup_init(&symlink, resolve->l_path,
|
|
resolve->l_flags|PATH_RET_SYMLINK, &sym_vmp, &sym_vp);
|
|
symlink.l_vnode_lock = VNODE_READ;
|
|
symlink.l_vmnt_lock = VMNT_READ;
|
|
sym_vp = advance(res_vp, &symlink, rfp);
|
|
|
|
if (sym_vp != NULL && S_ISLNK(sym_vp->v_mode)) {
|
|
/* Last component is a symlink, but if we've been asked to not
|
|
* resolve it, return now.
|
|
*/
|
|
if (ret_on_symlink) {
|
|
break;
|
|
}
|
|
|
|
r = req_rdlink(sym_vp->v_fs_e, sym_vp->v_inode_nr, NONE,
|
|
resolve->l_path, PATH_MAX - 1, 1);
|
|
|
|
if (r < 0) {
|
|
/* Failed to read link */
|
|
err_code = r;
|
|
unlock_vnode(res_vp);
|
|
unlock_vmnt(*resolve->l_vmp);
|
|
put_vnode(res_vp);
|
|
*resolve->l_vmp = NULL;
|
|
*resolve->l_vnode = NULL;
|
|
res_vp = NULL;
|
|
break;
|
|
}
|
|
resolve->l_path[r] = '\0';
|
|
|
|
if (strrchr(resolve->l_path, '/') != NULL) {
|
|
unlock_vnode(sym_vp);
|
|
unlock_vmnt(*resolve->l_vmp);
|
|
if (sym_vmp != NULL)
|
|
unlock_vmnt(sym_vmp);
|
|
*resolve->l_vmp = NULL;
|
|
put_vnode(sym_vp);
|
|
sym_vp = NULL;
|
|
|
|
symloop++;
|
|
|
|
/* Relative symlinks are relative to res_vp, not cwd */
|
|
if (resolve->l_path[0] != '/') {
|
|
loop_start = res_vp;
|
|
} else {
|
|
/* Absolute symlink, forget about res_vp */
|
|
unlock_vnode(res_vp);
|
|
put_vnode(res_vp);
|
|
}
|
|
|
|
continue;
|
|
}
|
|
}
|
|
break;
|
|
} while (symloop < SYMLOOP_MAX);
|
|
|
|
if (symloop >= SYMLOOP_MAX) {
|
|
err_code = ELOOP;
|
|
res_vp = NULL;
|
|
}
|
|
|
|
if (sym_vp != NULL) {
|
|
unlock_vnode(sym_vp);
|
|
if (sym_vmp != NULL) {
|
|
unlock_vmnt(sym_vmp);
|
|
}
|
|
put_vnode(sym_vp);
|
|
}
|
|
|
|
if (loop_start != NULL) {
|
|
unlock_vnode(loop_start);
|
|
put_vnode(loop_start);
|
|
}
|
|
|
|
/* Copy the directory entry back to user_fullpath */
|
|
strncpy(resolve->l_path, dir_entry, NAME_MAX + 1);
|
|
|
|
/* Turn PATH_RET_SYMLINK flag back on if it was on */
|
|
if (ret_on_symlink) resolve->l_flags |= PATH_RET_SYMLINK;
|
|
|
|
return(res_vp);
|
|
}
|
|
|
|
/*===========================================================================*
|
|
* lookup *
|
|
*===========================================================================*/
|
|
PRIVATE int lookup(start_node, resolve, result_node, rfp)
|
|
struct vnode *start_node;
|
|
struct lookup *resolve;
|
|
node_details_t *result_node;
|
|
struct fproc *rfp;
|
|
{
|
|
/* Resolve a path name relative to start_node. */
|
|
|
|
int r, symloop;
|
|
endpoint_t fs_e;
|
|
size_t path_off, path_left_len;
|
|
ino_t dir_ino, root_ino;
|
|
uid_t uid;
|
|
gid_t gid;
|
|
struct vnode *dir_vp;
|
|
struct vmnt *vmp, *vmpres;
|
|
struct lookup_res res;
|
|
|
|
assert(resolve->l_vmp);
|
|
assert(resolve->l_vnode);
|
|
|
|
*(resolve->l_vmp) = vmpres = NULL; /* No vmnt found nor locked yet */
|
|
|
|
/* Empty (start) path? */
|
|
if (resolve->l_path[0] == '\0') {
|
|
result_node->inode_nr = 0;
|
|
return(ENOENT);
|
|
}
|
|
|
|
if (!rfp->fp_rd || !rfp->fp_wd) {
|
|
printf("VFS: lookup %d: no rd/wd\n", rfp->fp_endpoint);
|
|
return(ENOENT);
|
|
}
|
|
|
|
fs_e = start_node->v_fs_e;
|
|
dir_ino = start_node->v_inode_nr;
|
|
vmpres = find_vmnt(fs_e);
|
|
|
|
if (vmpres == NULL) return(EIO); /* mountpoint vanished? */
|
|
|
|
/* Is the process' root directory on the same partition?,
|
|
* if so, set the chroot directory too. */
|
|
if (rfp->fp_rd->v_dev == rfp->fp_wd->v_dev)
|
|
root_ino = rfp->fp_rd->v_inode_nr;
|
|
else
|
|
root_ino = 0;
|
|
|
|
/* Set user and group ids according to the system call */
|
|
uid = (call_nr == ACCESS ? rfp->fp_realuid : rfp->fp_effuid);
|
|
gid = (call_nr == ACCESS ? rfp->fp_realgid : rfp->fp_effgid);
|
|
|
|
symloop = 0; /* Number of symlinks seen so far */
|
|
|
|
/* Lock vmnt */
|
|
if ((r = lock_vmnt(vmpres, resolve->l_vmnt_lock)) != OK) {
|
|
if (r == EBUSY) /* vmnt already locked */
|
|
vmpres = NULL;
|
|
else
|
|
return(r);
|
|
}
|
|
*(resolve->l_vmp) = vmpres;
|
|
|
|
/* Issue the request */
|
|
r = req_lookup(fs_e, dir_ino, root_ino, uid, gid, resolve, &res, rfp);
|
|
|
|
if (r != OK && r != EENTERMOUNT && r != ELEAVEMOUNT && r != ESYMLINK) {
|
|
if (vmpres) unlock_vmnt(vmpres);
|
|
*(resolve->l_vmp) = NULL;
|
|
return(r); /* i.e., an error occured */
|
|
}
|
|
|
|
/* While the response is related to mount control set the
|
|
* new requests respectively */
|
|
while (r == EENTERMOUNT || r == ELEAVEMOUNT || r == ESYMLINK) {
|
|
/* Update user_fullpath to reflect what's left to be parsed. */
|
|
path_off = res.char_processed;
|
|
path_left_len = strlen(&resolve->l_path[path_off]);
|
|
memmove(resolve->l_path, &resolve->l_path[path_off], path_left_len);
|
|
resolve->l_path[path_left_len] = '\0'; /* terminate string */
|
|
|
|
/* Update the current value of the symloop counter */
|
|
symloop += res.symloop;
|
|
if (symloop > SYMLOOP_MAX) {
|
|
if (vmpres) unlock_vmnt(vmpres);
|
|
*(resolve->l_vmp) = NULL;
|
|
return(ELOOP);
|
|
}
|
|
|
|
/* Symlink encountered with absolute path */
|
|
if (r == ESYMLINK) {
|
|
dir_vp = rfp->fp_rd;
|
|
vmp = NULL;
|
|
} else if (r == EENTERMOUNT) {
|
|
/* Entering a new partition */
|
|
dir_vp = NULL;
|
|
/* Start node is now the mounted partition's root node */
|
|
for (vmp = &vmnt[0]; vmp != &vmnt[NR_MNTS]; ++vmp) {
|
|
if (vmp->m_dev != NO_DEV && vmp->m_mounted_on) {
|
|
if (vmp->m_mounted_on->v_inode_nr == res.inode_nr &&
|
|
vmp->m_mounted_on->v_fs_e == res.fs_e) {
|
|
dir_vp = vmp->m_root_node;
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
if (dir_vp == NULL) {
|
|
printf("VFS: path lookup error; root node not found\n");
|
|
if (vmpres) unlock_vmnt(vmpres);
|
|
*(resolve->l_vmp) = NULL;
|
|
return(EIO);
|
|
}
|
|
} else {
|
|
/* Climbing up mount */
|
|
/* Find the vmnt that represents the partition on
|
|
* which we "climb up". */
|
|
if ((vmp = find_vmnt(res.fs_e)) == NULL) {
|
|
panic("VFS lookup: can't find parent vmnt");
|
|
}
|
|
|
|
/* Make sure that the child FS does not feed a bogus path
|
|
* to the parent FS. That is, when we climb up the tree, we
|
|
* must've encountered ".." in the path, and that is exactly
|
|
* what we're going to feed to the parent */
|
|
if(strncmp(resolve->l_path, "..", 2) != 0 ||
|
|
(resolve->l_path[2] != '\0' && resolve->l_path[2] != '/')) {
|
|
printf("VFS: bogus path: %s\n", resolve->l_path);
|
|
if (vmpres) unlock_vmnt(vmpres);
|
|
*(resolve->l_vmp) = NULL;
|
|
return(ENOENT);
|
|
}
|
|
|
|
/* Start node is the vnode on which the partition is
|
|
* mounted */
|
|
dir_vp = vmp->m_mounted_on;
|
|
}
|
|
|
|
/* Set the starting directories inode number and FS endpoint */
|
|
fs_e = dir_vp->v_fs_e;
|
|
dir_ino = dir_vp->v_inode_nr;
|
|
|
|
/* Is the process' root directory on the same partition?,
|
|
* if so, set the chroot directory too. */
|
|
if (dir_vp->v_dev == rfp->fp_rd->v_dev)
|
|
root_ino = rfp->fp_rd->v_inode_nr;
|
|
else
|
|
root_ino = 0;
|
|
|
|
/* Unlock a previously locked vmnt if locked and lock new vmnt */
|
|
if (vmpres) unlock_vmnt(vmpres);
|
|
vmpres = find_vmnt(fs_e);
|
|
if (vmpres == NULL) return(EIO); /* mount point vanished? */
|
|
if ((r = lock_vmnt(vmpres, resolve->l_vmnt_lock)) != OK) {
|
|
if (r == EBUSY)
|
|
vmpres = NULL; /* Already locked */
|
|
else
|
|
return(r);
|
|
}
|
|
*(resolve->l_vmp) = vmpres;
|
|
|
|
r = req_lookup(fs_e, dir_ino, root_ino, uid, gid, resolve, &res, rfp);
|
|
|
|
if (r != OK && r != EENTERMOUNT && r != ELEAVEMOUNT && r != ESYMLINK) {
|
|
if (vmpres) unlock_vmnt(vmpres);
|
|
*(resolve->l_vmp) = NULL;
|
|
return(r);
|
|
}
|
|
}
|
|
|
|
/* Fill in response fields */
|
|
result_node->inode_nr = res.inode_nr;
|
|
result_node->fmode = res.fmode;
|
|
result_node->fsize = res.fsize;
|
|
result_node->dev = res.dev;
|
|
result_node->fs_e = res.fs_e;
|
|
result_node->uid = res.uid;
|
|
result_node->gid = res.gid;
|
|
|
|
return(r);
|
|
}
|
|
|
|
/*===========================================================================*
|
|
* lookup_init *
|
|
*===========================================================================*/
|
|
PUBLIC void lookup_init(resolve, path, flags, vmp, vp)
|
|
struct lookup *resolve;
|
|
char *path;
|
|
int flags;
|
|
struct vmnt **vmp;
|
|
struct vnode **vp;
|
|
{
|
|
assert(vmp != NULL);
|
|
assert(vp != NULL);
|
|
|
|
resolve->l_path = path;
|
|
resolve->l_flags = flags;
|
|
resolve->l_vmp = vmp;
|
|
resolve->l_vnode = vp;
|
|
resolve->l_vmnt_lock = TLL_NONE;
|
|
resolve->l_vnode_lock = TLL_NONE;
|
|
*vmp = NULL; /* Initialize lookup result to NULL */
|
|
*vp = NULL;
|
|
}
|
|
|
|
/*===========================================================================*
|
|
* get_name *
|
|
*===========================================================================*/
|
|
PUBLIC int get_name(dirp, entry, ename)
|
|
struct vnode *dirp;
|
|
struct vnode *entry;
|
|
char ename[NAME_MAX + 1];
|
|
{
|
|
u64_t pos, new_pos;
|
|
int r, consumed, totalbytes;
|
|
char buf[(sizeof(struct dirent) + NAME_MAX) * 8];
|
|
struct dirent *cur;
|
|
|
|
pos = make64(0, 0);
|
|
|
|
if ((dirp->v_mode & I_TYPE) != I_DIRECTORY) {
|
|
return(EBADF);
|
|
}
|
|
|
|
do {
|
|
r = req_getdents(dirp->v_fs_e, dirp->v_inode_nr, pos, buf, sizeof(buf),
|
|
&new_pos, 1);
|
|
|
|
if (r == 0) {
|
|
return(ENOENT); /* end of entries -- matching inode !found */
|
|
} else if (r < 0) {
|
|
return(r); /* error */
|
|
}
|
|
|
|
consumed = 0; /* bytes consumed */
|
|
totalbytes = r; /* number of bytes to consume */
|
|
|
|
do {
|
|
cur = (struct dirent *) (buf + consumed);
|
|
if (entry->v_inode_nr == cur->d_ino) {
|
|
/* found the entry we were looking for */
|
|
strncpy(ename, cur->d_name, NAME_MAX);
|
|
ename[NAME_MAX] = '\0';
|
|
return(OK);
|
|
}
|
|
|
|
/* not a match -- move on to the next dirent */
|
|
consumed += cur->d_reclen;
|
|
} while (consumed < totalbytes);
|
|
|
|
pos = new_pos;
|
|
} while (1);
|
|
}
|
|
|
|
/*===========================================================================*
|
|
* canonical_path *
|
|
*===========================================================================*/
|
|
PUBLIC int canonical_path(orig_path, rfp)
|
|
char orig_path[PATH_MAX];
|
|
struct fproc *rfp;
|
|
{
|
|
/* Find canonical path of a given path */
|
|
int len = 0;
|
|
int r, symloop = 0;
|
|
struct vnode *dir_vp, *parent_dir;
|
|
struct vmnt *dir_vmp, *parent_vmp;
|
|
char component[NAME_MAX+1]; /* NAME_MAX does /not/ include '\0' */
|
|
char temp_path[PATH_MAX];
|
|
struct lookup resolve;
|
|
|
|
dir_vp = NULL;
|
|
strncpy(temp_path, orig_path, PATH_MAX);
|
|
temp_path[PATH_MAX - 1] = '\0';
|
|
|
|
/* First resolve path to the last directory holding the file */
|
|
do {
|
|
if (dir_vp) {
|
|
unlock_vnode(dir_vp);
|
|
unlock_vmnt(dir_vmp);
|
|
put_vnode(dir_vp);
|
|
}
|
|
|
|
lookup_init(&resolve, temp_path, PATH_NOFLAGS, &dir_vmp, &dir_vp);
|
|
resolve.l_vmnt_lock = VMNT_READ;
|
|
resolve.l_vnode_lock = VNODE_READ;
|
|
if ((dir_vp = last_dir(&resolve, rfp)) == NULL) return(err_code);
|
|
|
|
/* dir_vp points to dir and resolve path now contains only the
|
|
* filename.
|
|
*/
|
|
strncpy(orig_path, temp_path, NAME_MAX); /* Store file name */
|
|
|
|
/* check if the file is a symlink, if so resolve it */
|
|
r = rdlink_direct(orig_path, temp_path, rfp);
|
|
|
|
if (r <= 0)
|
|
break;
|
|
|
|
/* encountered a symlink -- loop again */
|
|
strncpy(orig_path, temp_path, PATH_MAX - 1);
|
|
symloop++;
|
|
} while (symloop < SYMLOOP_MAX);
|
|
|
|
if (symloop >= SYMLOOP_MAX) {
|
|
if (dir_vp) {
|
|
unlock_vnode(dir_vp);
|
|
unlock_vmnt(dir_vmp);
|
|
put_vnode(dir_vp);
|
|
}
|
|
return(ELOOP);
|
|
}
|
|
|
|
/* We've got the filename and the actual directory holding the file. From
|
|
* here we start building up the canonical path by climbing up the tree */
|
|
while (dir_vp != rfp->fp_rd) {
|
|
|
|
strcpy(temp_path, "..");
|
|
|
|
/* check if we're at the root node of the file system */
|
|
if (dir_vp->v_vmnt->m_root_node == dir_vp) {
|
|
unlock_vnode(dir_vp);
|
|
unlock_vmnt(dir_vmp);
|
|
put_vnode(dir_vp);
|
|
dir_vp = dir_vp->v_vmnt->m_mounted_on;
|
|
dir_vmp = dir_vp->v_vmnt;
|
|
if (lock_vmnt(dir_vmp, VMNT_READ) != OK)
|
|
panic("failed to lock vmnt");
|
|
if (lock_vnode(dir_vp, VNODE_READ) != OK)
|
|
panic("failed to lock vnode");
|
|
dup_vnode(dir_vp);
|
|
}
|
|
|
|
lookup_init(&resolve, temp_path, PATH_NOFLAGS, &parent_vmp,
|
|
&parent_dir);
|
|
resolve.l_vmnt_lock = VMNT_READ;
|
|
resolve.l_vnode_lock = VNODE_READ;
|
|
|
|
if ((parent_dir = advance(dir_vp, &resolve, rfp)) == NULL) {
|
|
unlock_vnode(dir_vp);
|
|
unlock_vmnt(dir_vmp);
|
|
put_vnode(dir_vp);
|
|
return(err_code);
|
|
}
|
|
|
|
/* now we have to retrieve the name of the parent directory */
|
|
if (get_name(parent_dir, dir_vp, component) != OK) {
|
|
unlock_vnode(parent_dir);
|
|
unlock_vmnt(parent_vmp);
|
|
unlock_vnode(dir_vp);
|
|
unlock_vmnt(dir_vmp);
|
|
put_vnode(parent_dir);
|
|
put_vnode(dir_vp);
|
|
return(ENOENT);
|
|
}
|
|
|
|
len += strlen(component) + 1;
|
|
if (len >= PATH_MAX) {
|
|
/* adding the component to orig_path would exceed PATH_MAX */
|
|
unlock_vnode(parent_dir);
|
|
unlock_vmnt(parent_vmp);
|
|
unlock_vnode(dir_vp);
|
|
unlock_vmnt(dir_vmp);
|
|
put_vnode(parent_dir);
|
|
put_vnode(dir_vp);
|
|
return(ENOMEM);
|
|
}
|
|
|
|
/* Store result of component in orig_path. First make space by moving
|
|
* the contents of orig_path to the right. Move strlen + 1 bytes to
|
|
* include the terminating '\0'. Move to strlen + 1 bytes to reserve
|
|
* space for the slash.
|
|
*/
|
|
memmove(orig_path+strlen(component)+1, orig_path, strlen(orig_path)+1);
|
|
/* Copy component into canon_path */
|
|
memmove(orig_path, component, strlen(component));
|
|
/* Put slash into place */
|
|
orig_path[strlen(component)] = '/';
|
|
|
|
/* Store parent_dir result, and continue the loop once more */
|
|
unlock_vnode(dir_vp);
|
|
unlock_vmnt(dir_vmp);
|
|
put_vnode(dir_vp);
|
|
dir_vp = parent_dir;
|
|
}
|
|
|
|
unlock_vnode(dir_vp);
|
|
unlock_vmnt(parent_vmp);
|
|
|
|
put_vnode(dir_vp);
|
|
|
|
/* add the leading slash */
|
|
if (strlen(orig_path) >= PATH_MAX) return(ENAMETOOLONG);
|
|
memmove(orig_path+1, orig_path, strlen(orig_path));
|
|
orig_path[0] = '/';
|
|
|
|
return(OK);
|
|
}
|
|
|
|
/*===========================================================================*
|
|
* check_perms *
|
|
*===========================================================================*/
|
|
PRIVATE int check_perms(ep, io_gr, pathlen)
|
|
endpoint_t ep;
|
|
cp_grant_id_t io_gr;
|
|
size_t pathlen;
|
|
{
|
|
int r, slot;
|
|
struct vnode *vp;
|
|
struct vmnt *vmp;
|
|
struct fproc *rfp;
|
|
char canon_path[PATH_MAX];
|
|
struct lookup resolve;
|
|
|
|
if (isokendpt(ep, &slot) != OK) return(EINVAL);
|
|
if (pathlen < UNIX_PATH_MAX || pathlen >= PATH_MAX) return(EINVAL);
|
|
|
|
rfp = &(fproc[slot]);
|
|
r = sys_safecopyfrom(PFS_PROC_NR, io_gr, (vir_bytes) 0,
|
|
(vir_bytes) canon_path, pathlen, D);
|
|
if (r != OK) return(r);
|
|
canon_path[pathlen] = '\0';
|
|
|
|
/* Turn path into canonical path to the socket file */
|
|
if ((r = canonical_path(canon_path, rfp)) != OK)
|
|
return(r);
|
|
|
|
if (strlen(canon_path) >= pathlen) return(ENAMETOOLONG);
|
|
|
|
/* copy canon_path back to PFS */
|
|
r = sys_safecopyto(PFS_PROC_NR, (cp_grant_id_t) io_gr, (vir_bytes) 0,
|
|
(vir_bytes) canon_path, pathlen, D);
|
|
if (r != OK) return(r);
|
|
|
|
/* Now do permissions checking */
|
|
lookup_init(&resolve, canon_path, PATH_NOFLAGS, &vmp, &vp);
|
|
resolve.l_vmnt_lock = VMNT_READ;
|
|
resolve.l_vnode_lock = VNODE_READ;
|
|
if ((vp = eat_path(&resolve, rfp)) == NULL) return(err_code);
|
|
|
|
/* check permissions */
|
|
r = forbidden(rfp, vp, (R_BIT | W_BIT));
|
|
|
|
unlock_vnode(vp);
|
|
unlock_vmnt(vmp);
|
|
|
|
put_vnode(vp);
|
|
return(r);
|
|
}
|
|
|
|
/*===========================================================================*
|
|
* do_check_perms *
|
|
*===========================================================================*/
|
|
PUBLIC int do_check_perms(void)
|
|
{
|
|
return check_perms(m_in.USER_ENDPT, (cp_grant_id_t) m_in.IO_GRANT,
|
|
(size_t) m_in.COUNT);
|
|
}
|