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