minix/servers/iso9660fs/read.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

338 lines
9.6 KiB
C

#include "inc.h"
#include <minix/com.h>
#include <minix/vfsif.h>
#include <fcntl.h>
#include "buf.h"
PRIVATE char getdents_buf[GETDENTS_BUFSIZ];
/*===========================================================================*
* fs_read *
*===========================================================================*/
PUBLIC int fs_read(void) {
int r, chunk, block_size;
int nrbytes;
cp_grant_id_t gid;
off_t position, f_size, bytes_left;
unsigned int off, cum_io;
int completed;
struct dir_record *dir;
r = OK;
/* Try to get inode according to its index */
dir = get_dir_record(fs_m_in.REQ_INODE_NR);
if (dir == NULL) return(EINVAL); /* no inode found */
position = fs_m_in.REQ_SEEK_POS_LO;
nrbytes = (unsigned) fs_m_in.REQ_NBYTES; /* number of bytes to read */
block_size = v_pri.logical_block_size_l;
gid = fs_m_in.REQ_GRANT;
f_size = dir->d_file_size;
rdwt_err = OK; /* set to EIO if disk error occurs */
cum_io = 0;
/* Split the transfer into chunks that don't span two blocks. */
while (nrbytes != 0) {
off = (unsigned int) (position % block_size);
chunk = MIN(nrbytes, block_size - off);
if (chunk < 0) chunk = block_size - off;
bytes_left = f_size - position;
if (position >= f_size) break; /* we are beyond EOF */
if (chunk > bytes_left) chunk = (int) bytes_left;
/* Read or write 'chunk' bytes. */
r = read_chunk(dir, cvul64(position), off, chunk, (unsigned) nrbytes,
gid, cum_io, block_size, &completed);
if (r != OK) break; /* EOF reached */
if (rdwt_err < 0) break;
/* Update counters and pointers. */
nrbytes -= chunk; /* bytes yet to be read */
cum_io += chunk; /* bytes read so far */
position += chunk; /* position within the file */
}
fs_m_out.RES_SEEK_POS_LO = position;
if (rdwt_err != OK) r = rdwt_err; /* check for disk error */
if (rdwt_err == END_OF_FILE) r = OK;
fs_m_out.RES_NBYTES = cum_io; /*dir->d_file_size;*/
release_dir_record(dir);
return(r);
}
/*===========================================================================*
* fs_bread *
*===========================================================================*/
PUBLIC int fs_bread(void)
{
int r, rw_flag, chunk, block_size;
cp_grant_id_t gid;
int nrbytes;
u64_t position;
unsigned int off, cum_io;
mode_t mode_word;
int completed, r2 = OK;
struct dir_record *dir;
r = OK;
rw_flag = (fs_m_in.m_type == REQ_BREAD ? READING : WRITING);
gid = fs_m_in.REQ_GRANT;
position = make64(fs_m_in.REQ_SEEK_POS_LO, fs_m_in.REQ_SEEK_POS_HI);
nrbytes = (unsigned) fs_m_in.REQ_NBYTES;
block_size = v_pri.logical_block_size_l;
dir = v_pri.dir_rec_root;
if(rw_flag == WRITING) return (EIO); /* Not supported */
rdwt_err = OK; /* set to EIO if disk error occurs */
cum_io = 0;
/* Split the transfer into chunks that don't span two blocks. */
while (nrbytes != 0) {
off = rem64u(position, block_size); /* offset in blk*/
chunk = MIN(nrbytes, block_size - off);
if (chunk < 0) chunk = block_size - off;
/* Read 'chunk' bytes. */
r = read_chunk(dir, position, off, chunk, (unsigned) nrbytes,
gid, cum_io, block_size, &completed);
if (r != OK) break; /* EOF reached */
if (rdwt_err < 0) break;
/* Update counters and pointers. */
nrbytes -= chunk; /* bytes yet to be read */
cum_io += chunk; /* bytes read so far */
position= add64ul(position, chunk); /* position within the file */
}
fs_m_out.RES_SEEK_POS_LO = ex64lo(position);
fs_m_out.RES_SEEK_POS_HI = ex64hi(position);
if (rdwt_err != OK) r = rdwt_err; /* check for disk error */
if (rdwt_err == END_OF_FILE) r = OK;
fs_m_out.RES_NBYTES = cum_io;
return(r);
}
/*===========================================================================*
* fs_getdents *
*===========================================================================*/
PUBLIC int fs_getdents(void) {
struct dir_record *dir;
ino_t ino;
cp_grant_id_t gid;
size_t size_to_read, block_size;
off_t pos, block_pos, block, cur_pos, tmpbuf_offset, userbuf_off;
struct buf *bp;
struct dir_record *dir_tmp;
struct dirent *dirp;
int r,done,o,len,reclen;
char *cp;
char name[NAME_MAX + 1];
char name_old[NAME_MAX + 1];
/* Initialize the tmp arrays */
memset(name,'\0',NAME_MAX);
memset(name_old,'\0',NAME_MAX);
/* Get input parameters */
ino = fs_m_in.REQ_INODE_NR;
gid = fs_m_in.REQ_GRANT;
size_to_read = fs_m_in.REQ_MEM_SIZE;
pos = fs_m_in.REQ_SEEK_POS_LO;
block_size = v_pri.logical_block_size_l;
cur_pos = pos; /* The current position */
tmpbuf_offset = 0;
userbuf_off = 0;
memset(getdents_buf, '\0', GETDENTS_BUFSIZ); /* Avoid leaking any data */
if ((dir = get_dir_record(ino)) == NULL) return(EINVAL);
block = dir->loc_extent_l; /* First block of the directory */
block += pos / block_size; /* Shift to the block where start to read */
done = FALSE;
while (cur_pos<dir->d_file_size) {
bp = get_block(block); /* Get physical block */
if (bp == NIL_BUF) {
release_dir_record(dir);
return(EINVAL);
}
block_pos = cur_pos % block_size; /* Position where to start read */
while (block_pos < block_size) {
dir_tmp = get_free_dir_record();
create_dir_record(dir_tmp,bp->b_data + block_pos,
block*block_size + block_pos);
if (dir_tmp->length == 0) { /* EOF. I exit and return 0s */
block_pos = block_size;
done = TRUE;
release_dir_record(dir_tmp);
} else { /* The dir record is valid. Copy data... */
if (dir_tmp->file_id[0] == 0) strcpy(name,".");
else if (dir_tmp->file_id[0] == 1) strcpy(name,"..");
else {
/* Extract the name from the field file_id */
strncpy(name, dir_tmp->file_id,
dir_tmp->length_file_id);
name[dir_tmp->length_file_id] = 0;
/* Tidy up file name */
cp = memchr(name, ';', NAME_MAX);
if (cp != NULL) name[cp - name] = 0;
/*If no file extension, then remove final '.'*/
if (name[strlen(name) - 1] == '.')
name[strlen(name) - 1] = '\0';
}
if (strcmp(name_old, name) == 0) {
cur_pos += dir_tmp->length;
release_dir_record(dir_tmp);
continue;
}
strcpy(name_old,name);
/* Compute the length of the name */
cp = memchr(name, '\0', NAME_MAX);
if (cp == NULL) len = NAME_MAX;
else len= cp - name;
/* Compute record length */
reclen = offsetof(struct dirent, d_name) + len + 1;
o = (reclen % sizeof(long));
if (o != 0)
reclen += sizeof(long) - o;
/* If the new record does not fit, then copy the buffer
* and start from the beginning. */
if (tmpbuf_offset + reclen > GETDENTS_BUFSIZ) {
r = sys_safecopyto(FS_PROC_NR, gid, userbuf_off,
(vir_bytes)getdents_buf, tmpbuf_offset, D);
if (r != OK)
panic(__FILE__,
"fs_getdents: sys_safecopyto failed\n",r);
userbuf_off += tmpbuf_offset;
tmpbuf_offset= 0;
}
/* The standard data structure is created using the
* data in the buffer. */
dirp = (struct dirent *) &getdents_buf[tmpbuf_offset];
dirp->d_ino = (ino_t)(bp->b_data + block_pos);
dirp->d_off= cur_pos;
dirp->d_reclen= reclen;
memcpy(dirp->d_name, name, len);
dirp->d_name[len]= '\0';
tmpbuf_offset += reclen;
cur_pos += dir_tmp->length;
release_dir_record(dir_tmp);
}
block_pos += dir_tmp->length;
}
put_block(bp); /* release the block */
if (done == TRUE) break;
cur_pos += block_size - cur_pos;
block++; /* read the next one */
}
if (tmpbuf_offset != 0) {
r = sys_safecopyto(FS_PROC_NR, gid, userbuf_off,
(vir_bytes) getdents_buf, tmpbuf_offset, D);
if (r != OK)
panic(__FILE__, "fs_getdents: sys_safecopyto failed\n", r);
userbuf_off += tmpbuf_offset;
}
fs_m_out.RES_NBYTES = userbuf_off;
fs_m_out.RES_SEEK_POS_LO = cur_pos;
release_dir_record(dir); /* release the inode */
return(OK);
}
/*===========================================================================*
* read_chunk *
*===========================================================================*/
PUBLIC int read_chunk(dir, position, off, chunk, left, gid, buf_off, block_size, completed)
register struct dir_record *dir;/* pointer to inode for file to be rd/wr */
u64_t position; /* position within file to read or write */
unsigned off; /* off within the current block */
int chunk; /* number of bytes to read or write */
unsigned left; /* max number of bytes wanted after position */
cp_grant_id_t gid; /* grant */
unsigned buf_off; /* offset in grant */
int block_size; /* block size of FS operating on */
int *completed; /* number of bytes copied */
{
register struct buf *bp;
register int r = OK;
int n;
block_t b;
dev_t dev;
int file_unit, rel_block, offset;
*completed = 0;
if ((ex64lo(position) <= dir->d_file_size) &&
(ex64lo(position) > dir->data_length_l)) {
while ((dir->d_next != NULL) && (ex64lo(position) > dir->data_length_l)) {
position = sub64ul(position, dir->data_length_l);
dir = dir->d_next;
}
}
if (dir->inter_gap_size != 0) {
rel_block = div64u(position, block_size);
file_unit = rel_block / dir->data_length_l;
offset = rel_block % dir->file_unit_size;
b = dir->loc_extent_l + (dir->file_unit_size +
dir->inter_gap_size) * file_unit + offset;
} else {
b = dir->loc_extent_l + div64u(position, block_size); /* Physical position
* to read. */
}
bp = get_block(b);
/* In all cases, bp now points to a valid buffer. */
if (bp == NIL_BUF) {
panic(__FILE__,"bp not valid in rw_chunk, this can't happen", NO_NUM);
}
r = sys_safecopyto(FS_PROC_NR, gid, buf_off,
(vir_bytes) (bp->b_data+off), (phys_bytes) chunk, D);
put_block(bp);
return(r);
}