minix/servers/iso9660fs/path.c
Thomas Veerman 958b25be50 - Introduce support for sticky bit.
- Revise VFS-FS protocol and update VFS/MFS/ISOFS accordingly.
- Clean up MFS by removing old, dead code (backwards compatibility is broken by
  the new VFS-FS protocol, anyway) and rewrite other parts. Also, make sure all
  functions have proper banners and prototypes.
- VFS should always provide a (syntactically) valid path to the FS; no need for
  the FS to do sanity checks when leaving/entering mount points.
- Fix several bugs in MFS:
  - Several path lookup bugs in MFS.
  - A link can be too big for the path buffer.
  - A mountpoint can become inaccessible when the creation of a new inode
    fails, because the inode already exists and is a mountpoint.
- Introduce support for supplemental groups.
- Add test 46 to test supplemental group functionality (and removed obsolete
  suppl. tests from test 2).
- Clean up VFS (not everything is done yet).
- ISOFS now opens device read-only. This makes the -r flag in the mount command
  unnecessary (but will still report to be mounted read-write).
- Introduce PipeFS. PipeFS is a new FS that handles all anonymous and
  named pipes. However, named pipes still reside on the (M)FS, as they are part
  of the file system on disk. To make this work VFS now has a concept of
  'mapped' inodes, which causes read, write, truncate and stat requests to be
  redirected to the mapped FS, and all other requests to the original FS.
2009-12-20 20:27:14 +00:00

377 lines
9.9 KiB
C

#include "inc.h"
#include <string.h>
#include <minix/com.h>
#include <minix/vfsif.h>
#include "buf.h"
FORWARD _PROTOTYPE( char *get_name, (char *name, char string[NAME_MAX+1]) );
FORWARD _PROTOTYPE( int parse_path, (ino_t dir_ino, ino_t root_ino, int flags,
struct dir_record **res_inop,
size_t *offsetp) );
/*===========================================================================*
* fs_lookup *
*===========================================================================*/
PUBLIC int fs_lookup() {
cp_grant_id_t grant;
int r, r1, len, flags;
size_t offset, size;
ino_t dir_ino, root_ino;
struct dir_record *dir;
grant = fs_m_in.REQ_GRANT;
size = fs_m_in.REQ_PATH_SIZE; /* Size of the buffer */
len = fs_m_in.REQ_PATH_LEN; /* including terminating nul */
dir_ino = fs_m_in.REQ_DIR_INO;
root_ino = fs_m_in.REQ_ROOT_INO;
flags = fs_m_in.REQ_FLAGS;
caller_uid = fs_m_in.REQ_UID;
caller_gid = fs_m_in.REQ_GID;
/* Check length. */
if(len > sizeof(user_path)) return(E2BIG); /* too big for buffer */
if(len < 1) return(EINVAL); /* too small */
/* Copy the pathname and set up caller's user and group id */
r = sys_safecopyfrom(FS_PROC_NR, grant, 0, (vir_bytes) user_path,
(phys_bytes) len, D);
if (r != OK) {
printf("ISOFS %s:%d sys_safecopyfrom failed: %d\n",
__FILE__, __LINE__, r);
return(r);
}
/* Verify this is a null-terminated path. */
if(user_path[len-1] != '\0') return(EINVAL);
/* Lookup inode */
dir = NULL;
offset = 0;
r = parse_path(dir_ino, root_ino, flags, &dir, &offset);
if (r == ELEAVEMOUNT) {
/* Report offset and the error */
fs_m_out.RES_OFFSET = offset;
fs_m_out.RES_SYMLOOP = 0;
return(r);
}
if (r != OK && r != EENTERMOUNT) return(r);
fs_m_out.RES_INODE_NR = ID_DIR_RECORD(dir);
fs_m_out.RES_MODE = dir->d_mode;
fs_m_out.RES_FILE_SIZE_LO = dir->d_file_size;
fs_m_out.RES_SYMLOOP = 0;
fs_m_out.RES_UID = SYS_UID; /* root */
fs_m_out.RES_GID = SYS_GID; /* operator */
if (r == EENTERMOUNT) {
fs_m_out.RES_OFFSET = offset;
release_dir_record(dir);
}
return(r);
}
/* The search dir actually performs the operation of searching for the
* compoent ``string" in ldir_ptr. It returns the response and the number of
* the inode in numb. */
/*===========================================================================*
* search_dir *
*===========================================================================*/
PUBLIC int search_dir(ldir_ptr,string,numb)
register struct dir_record *ldir_ptr; /* dir record parent */
char string[NAME_MAX]; /* component to search for */
ino_t *numb; /* pointer to new dir record */
{
struct dir_record *dir_tmp;
register struct buf *bp,*bp2;
int pos,r,len;
char* comma_pos = NULL;
char tmp_string[NAME_MAX];
/* This function search a particular element (in string) in a inode and
* return its number */
/* Initialize the tmp array */
memset(tmp_string,'\0',NAME_MAX);
if ((ldir_ptr->d_mode & I_TYPE) != I_DIRECTORY) {
return(ENOTDIR);
}
r = OK;
if (strcmp(string,".") == 0) {
*numb = ID_DIR_RECORD(ldir_ptr);
return OK;
}
if (strcmp(string,"..") == 0 && ldir_ptr->loc_extent_l == v_pri.dir_rec_root->loc_extent_l) {
*numb = ROOT_INO_NR;
/* *numb = ID_DIR_RECORD(ldir_ptr); */
return OK;
}
/* Read the dir's content */
pos = ldir_ptr->ext_attr_rec_length;
bp = get_block(ldir_ptr->loc_extent_l);
if (bp == NIL_BUF)
return EINVAL;
while (pos < v_pri.logical_block_size_l) {
if ((dir_tmp = get_free_dir_record()) == NULL) {
put_block(bp);
return EINVAL;
}
if (create_dir_record(dir_tmp,bp->b_data + pos,
ldir_ptr->loc_extent_l*v_pri.logical_block_size_l + pos) == EINVAL)
return EINVAL;
if (dir_tmp->length == 0) {
release_dir_record(dir_tmp);
put_block(bp);
return EINVAL;
}
memcpy(tmp_string,dir_tmp->file_id,dir_tmp->length_file_id);
comma_pos = strchr(tmp_string,';');
if (comma_pos != NULL)
*comma_pos = 0;
else
tmp_string[dir_tmp->length_file_id] = 0;
if (tmp_string[strlen(tmp_string) - 1] == '.')
tmp_string[strlen(tmp_string) - 1] = '\0';
if (strcmp(tmp_string,string) == 0 ||
(dir_tmp->file_id[0] == 1 && strcmp(string,"..") == 0)) {
/* If the element is found or we are searchig for... */
if (dir_tmp->loc_extent_l == dir_records->loc_extent_l) {
/* In this case the inode is a root because the parent
* points to the same location than the inode. */
*numb = 1;
release_dir_record(dir_tmp);
put_block(bp);
return OK;
}
if (dir_tmp->ext_attr_rec_length != 0) {
dir_tmp->ext_attr = get_free_ext_attr();
create_ext_attr(dir_tmp->ext_attr,bp->b_data);
}
*numb = ID_DIR_RECORD(dir_tmp);
release_dir_record(dir_tmp);
put_block(bp);
return OK;
}
pos += dir_tmp->length;
release_dir_record(dir_tmp);
}
put_block(bp);
return EINVAL;
}
/*===========================================================================*
* parse_path *
*===========================================================================*/
PRIVATE int parse_path(dir_ino, root_ino, flags, res_inop, offsetp)
ino_t dir_ino;
ino_t root_ino;
int flags;
struct dir_record **res_inop;
size_t *offsetp;
{
int r;
char string[NAME_MAX+1];
char *cp, *ncp;
struct dir_record *start_dir, *old_dir;
/* Find starting inode inode according to the request message */
if ((start_dir = get_dir_record(dir_ino)) == NULL) {
printf("ISOFS: couldn't find starting inode %d\n", dir_ino);
return(ENOENT);
}
cp = user_path;
/* Scan the path component by component. */
while (TRUE) {
if (cp[0] == '\0') {
/* Empty path */
*res_inop= start_dir;
*offsetp += cp-user_path;
/* Return EENTERMOUNT if we are at a mount point */
if (start_dir->d_mountpoint)
return EENTERMOUNT;
return OK;
}
if (cp[0] == '/') {
/* Special case code. If the remaining path consists of just
* slashes, we need to look up '.'
*/
while(cp[0] == '/')
cp++;
if (cp[0] == '\0') {
strcpy(string, ".");
ncp = cp;
}
else
ncp = get_name(cp, string);
} else
/* Just get the first component */
ncp = get_name(cp, string);
/* Special code for '..'. A process is not allowed to leave a chrooted
* environment. A lookup of '..' at the root of a mounted filesystem
* has to return ELEAVEMOUNT.
*/
if (strcmp(string, "..") == 0) {
/* This condition is not necessary since it will never be the root filesystem */
/* if (start_dir == dir_records) { */
/* cp = ncp; */
/* continue; /\* Just ignore the '..' at a process' */
/* * root. */
/* *\/ */
/* } */
if (start_dir == dir_records) {
/* Climbing up mountpoint */
release_dir_record(start_dir);
*res_inop = NULL;
*offsetp += cp-user_path;
return ELEAVEMOUNT;
}
} else {
/* Only check for a mount point if we are not looking for '..'. */
if (start_dir->d_mountpoint) {
*res_inop= start_dir;
*offsetp += cp-user_path;
return EENTERMOUNT;
}
}
/* There is more path. Keep parsing. */
old_dir = start_dir;
r = advance(old_dir, string, &start_dir);
if (r != OK) {
release_dir_record(old_dir);
return r;
}
release_dir_record(old_dir);
cp = ncp;
}
}
/*===========================================================================*
* advance *
*===========================================================================*/
PUBLIC int advance(dirp, string, resp)
struct dir_record *dirp; /* inode for directory to be searched */
char string[NAME_MAX]; /* component name to look for */
struct dir_record **resp; /* resulting inode */
{
/* Given a directory and a component of a path, look up the component in
* the directory, find the inode, open it, and return a pointer to its inode
* slot.
*/
register struct dir_record *rip = NULL;
int r, inumb;
dev_t mnt_dev;
ino_t numb;
/* If 'string' is empty, yield same inode straight away. */
if (string[0] == '\0') {
return ENOENT;
}
/* Check for NULL. */
if (dirp == NULL) {
return EINVAL;
}
/* If 'string' is not present in the directory, signal error. */
if ( (r = search_dir(dirp, string, &numb)) != OK) {
return r;
}
/* The component has been found in the directory. Get inode. */
if ( (rip = get_dir_record((int) numb)) == NULL) {
return(err_code);
}
*resp= rip;
return OK;
}
/*===========================================================================*
* get_name *
*===========================================================================*/
PRIVATE char *get_name(path_name, string)
char *path_name; /* path name to parse */
char string[NAME_MAX+1]; /* component extracted from 'old_name' */
{
/* Given a pointer to a path name in fs space, 'path_name', copy the first
* component to 'string' (truncated if necessary, always nul terminated).
* A pointer to the string after the first component of the name as yet
* unparsed is returned. Roughly speaking,
* 'get_name' = 'path_name' - 'string'.
*
* This routine follows the standard convention that /usr/ast, /usr//ast,
* //usr///ast and /usr/ast/ are all equivalent.
*/
size_t len;
char *cp, *ep;
cp= path_name;
/* Skip leading slashes */
while (cp[0] == '/')
cp++;
/* Find the end of the first component */
ep= cp;
while(ep[0] != '\0' && ep[0] != '/')
ep++;
len= ep-cp;
/* Truncate the amount to be copied if it exceeds NAME_MAX */
if (len > NAME_MAX)
len= NAME_MAX;
/* Special case of the string at cp is empty */
if (len == 0)
{
/* Return "." */
strcpy(string, ".");
}
else
{
memcpy(string, cp, len);
string[len]= '\0';
}
return ep;
}