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minix/servers/iso9660fs/path.c
Thomas Veerman 471ad9384f Initial import of ISOFS by Jacopo Urbani
2009-10-01 14:00:27 +00:00

668 lines
19 KiB
C
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#include "inc.h"
#include <string.h>
#include <minix/com.h>
#include <minix/vfsif.h>
#include "buf.h"
FORWARD _PROTOTYPE(char *get_name, (char *old_name, char string [NAME_MAX]));
FORWARD _PROTOTYPE( char *get_name_s, (char *name, char string[NAME_MAX+1]) );
FORWARD _PROTOTYPE( int parse_path_s, (ino_t dir_ino, ino_t root_ino,
int flags, struct dir_record **res_inop,
size_t *offsetp));
FORWARD _PROTOTYPE( int advance_s, (struct dir_record *dirp,
char string[NAME_MAX], struct dir_record **resp));
/* Lookup is a function used to ``look up" a particular path. It is called
* very often. */
/*===========================================================================*
* lookup *
*===========================================================================*/
PUBLIC int lookup()
{
char string[PATH_MAX];
int s_error, flags;
int len;
struct dir_record *dir;
string[0] = '\0';
/* Check length. */
len = fs_m_in.REQ_PATH_LEN;
if(len > sizeof(user_path)) return E2BIG; /* too big for buffer */
if(len < 1) return EINVAL; /* too small for \0 */
/* Copy the pathname and set up caller's user and group id */
err_code = sys_datacopy(FS_PROC_NR, (vir_bytes) fs_m_in.REQ_PATH, SELF,
(vir_bytes) user_path, (phys_bytes) len);
if (err_code != OK) {
printf("i9660fs:%s:%d: sys_datacopy failed: %d\n", __FILE__, __LINE__, err_code);
return err_code;
}
/* Verify this is a null-terminated path. */
if(user_path[len-1] != '\0') {
printf("i9660fs:lookup: didn't get null-terminated string.\n");
return EINVAL;
}
caller_uid = fs_m_in.REQ_UID;
caller_gid = fs_m_in.REQ_GID;
flags = fs_m_in.REQ_FLAGS;
/* Clear RES_OFFSET for ENOENT */
fs_m_out.RES_OFFSET= 0;
/* Lookup inode */
dir = parse_path(user_path, string, flags);
/* Copy back the last name if it is required */
if (err_code != OK || (flags & PATH_PENULTIMATE)) {
s_error = sys_datacopy(SELF_E, (vir_bytes) string, FS_PROC_NR,
(vir_bytes) fs_m_in.REQ_USER_ADDR, (phys_bytes) NAME_MAX);
if (s_error != OK) {
printf("i9660fs:%s:%d: sys_datacopy failed: %d\n",
__FILE__, __LINE__, s_error);
return s_error;
}
}
/* Error or mount point encountered */
if (dir == NULL) {
if (err_code != EENTERMOUNT)
fs_m_out.RES_INODE_NR = 0; /* signal no inode */
return err_code;
}
fs_m_out.RES_INODE_NR = ID_DIR_RECORD(dir);
fs_m_out.RES_MODE = dir->d_mode;
fs_m_out.RES_FILE_SIZE = dir->d_file_size;
/* Drop inode (path parse increased the counter) */
release_dir_record(dir);
return err_code;
}
/*===========================================================================*
* fs_lookup_s *
*===========================================================================*/
PUBLIC int fs_lookup_s() {
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_L_GRANT;
size= fs_m_in.REQ_L_PATH_SIZE; /* Size of the buffer */
len = fs_m_in.REQ_L_PATH_LEN; /* including terminating nul */
offset= fs_m_in.REQ_L_PATH_OFF; /* offset in buffer */
dir_ino= fs_m_in.REQ_L_DIR_INO;
root_ino= fs_m_in.REQ_L_ROOT_INO;
flags = fs_m_in.REQ_L_FLAGS;
caller_uid = fs_m_in.REQ_L_UID;
caller_gid = fs_m_in.REQ_L_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, offset,
(vir_bytes) user_path, (phys_bytes) len, D);
if (r != OK) {
printf("iso9660fs:fs_lookup_s: sys_safecopyfrom failed: %d\n", r);
return r;
}
/* Verify this is a null-terminated path. */
if(user_path[len-1] != '\0') {
printf("iso9660fs:fs_lookup_s: didn't get null-terminated string.\n");
return EINVAL;
}
/* Lookup inode */
dir = NULL;
r = parse_path_s(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;
if (dir) panic(__FILE__, "fs_lookup_s: dir should be clear",
(unsigned)dir);
return r;
}
if (r != OK && r != EENTERMOUNT) {
if (dir)
panic(__FILE__, "fs_lookup_s: dir should be clear",
(unsigned)dir);
return r;
}
fs_m_out.RES_OFFSET = offset;
fs_m_out.RES_INODE_NR = ID_DIR_RECORD(dir);
fs_m_out.RES_MODE = dir->d_mode;
fs_m_out.RES_FILE_SIZE = dir->d_file_size;
fs_m_out.RES_SYMLOOP2 = 0;
fs_m_out.RES_UID = 0; /* root */
fs_m_out.RES_GID = 0; /* operator */
/* /\* Drop inode (path parse increased the counter) *\/ */
/* release_dir_record(dir); */
if (r == EENTERMOUNT)
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 will parse a particular path and return the final dir record.
* The final component of this path will be returned in string. It works in
* two ways: the first is PATH_PENULTIMATE and it returns the last dir of the
* path while the second is PATH_NON_SYMBOLIC where it returns the last
* component of the path. */
/*===========================================================================*
* parse_path *
*===========================================================================*/
PUBLIC struct dir_record *parse_path(path, string, action)
char *path; /* the path name to be parsed */
char string[NAME_MAX]; /* the final component is returned here */
int action; /* action on last part of path */
{
/* This is the actual code for last_dir and eat_path. Return the inode of
* the last directory and the name of object within that directory, or the
* inode of the last object (an empty name will be returned). Names are
* returned in string. If string is null the name is discarded. The action
* code determines how "last" is defined. If an error occurs, NIL_INODE
* will be returned with an error code in err_code.
*/
char *new_name;
char lstring[NAME_MAX];
struct dir_record *start_dir, *chroot_dir, *old_dir, *dir;
/* Find starting inode inode according to the request message */
if ((start_dir = get_dir_record(fs_m_in.REQ_INODE_NR)) == NULL) {
printf("I9660FS: couldn't find starting inode req_nr: %d %s\n", req_nr,
user_path);
err_code = ENOENT;
printf("%s, %d\n", __FILE__, __LINE__);
return NULL;
}
/* Set user and group ID */
caller_uid = fs_m_in.REQ_UID;
caller_gid = fs_m_in.REQ_GID;
/* No characters were processed yet */
path_processed = 0;
/* Current number of symlinks encountered */
symloop = fs_m_in.REQ_SYMLOOP;
if (*path == '\0') {
return start_dir;
}
if (string == (char *) 0) string = lstring;
/* Scan the path component by component. */
while (TRUE) {
int slashes = 0;
/* Extract one component. Skip slashes first. */
while (path[slashes] == '/') {
slashes++;
path_processed++;
}
fs_m_out.RES_OFFSET = path_processed; /* For ENOENT */
if ((new_name = get_name(path+slashes, string)) == (char*) 0) {
release_dir_record(start_dir); /* bad path in user space */
return(NULL);
}
if (*new_name == '\0' && (action & PATH_PENULTIMATE)) {
if ((start_dir->file_flags & I_TYPE) ==I_DIRECTORY) {
return(start_dir); /* normal exit */
} else {
/* last file of path prefix is not a directory */
release_dir_record(start_dir);
err_code = ENOTDIR;
return(NULL);
}
}
/* There is more path. Keep parsing. */
old_dir = start_dir;
start_dir = advance(&old_dir, string);
if (start_dir == NULL) {
if (*new_name == '\0' && (action & PATH_NONSYMBOLIC) != 0) {
return(old_dir);
}
else if (err_code == ENOENT) {
return(old_dir);
}
else {
release_dir_record(old_dir);
return(NULL);
}
}
if (*new_name != '\0') {
release_dir_record(old_dir);
path = new_name;
continue;
}
/* Either last name reached or symbolic link is opaque */
if ((action & PATH_NONSYMBOLIC) != 0) {
release_dir_record(start_dir);
return(old_dir);
} else {
release_dir_record(old_dir);
return(start_dir);
}
}
}
/* Parse the path in user_path, starting at dir_ino. If the path is the empty
* string, just return dir_ino. It is upto the caller to treat an empty
* path in a special way. Otherwise, if the path consists of just one or
* more slash ('/') characters, the path is replaced with ".". Otherwise,
* just look up the first (or only) component in path after skipping any
* leading slashes.
*/
/*===========================================================================*
* parse_path_s *
*===========================================================================*/
PRIVATE int parse_path_s(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("I9660FS: couldn't find starting inode req_nr: %d %s\n", req_nr,
user_path);
printf("%s, %d\n", __FILE__, __LINE__);
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_s(cp, string);
} else
/* Just get the first component */
ncp = get_name_s(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_s(old_dir, string, &start_dir);
if (r != OK) {
release_dir_record(old_dir);
return r;
}
release_dir_record(old_dir);
cp = ncp;
}
}
/* This function will return the componsent in ``string" looking in the dir
* pdirp... */
/*===========================================================================*
* advance *
*===========================================================================*/
PUBLIC struct dir_record *advance(pdirp, string)
struct dir_record **pdirp; /* inode for directory to be searched */
char string[NAME_MAX]; /* component name to look for */
{
/* 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. If it can't be done, return NULL.
*/
register struct dir_record *rip, *dirp;
int r, inumb;
dev_t mnt_dev;
ino_t numb;
dirp = *pdirp;
/* If 'string' is empty, yield same inode straight away. */
if (string[0] == '\0') {
return dirp;
}
/* Check for NULL. */
if (dirp == NULL) {
return(NULL);
}
/* If 'string' is not present in the directory, signal error. */
if ( (r = search_dir(dirp, string, &numb)) != OK) {
err_code = r;
return(NULL);
}
/* The component has been found in the directory. Get inode. */
if ( (rip = get_dir_record((int) numb)) == NULL) {
return(NULL);
}
return(rip);
}
/*===========================================================================*
* advance_s *
*===========================================================================*/
PRIVATE int advance_s(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(old_name, string)
char *old_name; /* path name to parse */
char string[NAME_MAX]; /* component extracted from 'old_name' */
{
/* Given a pointer to a path name in fs space, 'old_name', copy the next
* component to 'string' and pad with zeros. A pointer to that part of
* the name as yet unparsed is returned. Roughly speaking,
* 'get_name' = 'old_name' - 'string'.
*
* This routine follows the standard convention that /usr/ast, /usr//ast,
* //usr///ast and /usr/ast/ are all equivalent.
*/
register int c;
register char *np, *rnp;
np = string; /* 'np' points to current position */
rnp = old_name; /* 'rnp' points to unparsed string */
c = *rnp;
/* Copy the unparsed path, 'old_name', to the array, 'string'. */
while ( rnp < &old_name[PATH_MAX] && c != '/' && c != '\0') {
if (np < &string[NAME_MAX]) *np++ = c;
c = *++rnp; /* advance to next character */
path_processed++; /* count characters */
}
/* To make /usr/ast/ equivalent to /usr/ast, skip trailing slashes. */
while (c == '/' && rnp < &old_name[PATH_MAX]) {
c = *++rnp;
path_processed++; /* count characters */
}
if (np < &string[NAME_MAX]) *np = '\0'; /* Terminate string */
if (rnp >= &old_name[PATH_MAX]) {
err_code = ENAMETOOLONG;
return((char *) 0);
}
return(rnp);
}
/*===========================================================================*
* get_name_s *
*===========================================================================*/
PRIVATE char *get_name_s(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_s' = '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;
}
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