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