minix/lib/libpuffs/read.c
2012-03-25 21:58:14 +02:00

178 lines
4.5 KiB
C

/* Created (MFS based):
* February 2010 (Evgeniy Ivanov)
*/
#include "fs.h"
#include <stddef.h>
#include <string.h>
#include <stdlib.h>
#include <dirent.h>
#include <minix/com.h>
#include <minix/u64.h>
#include <minix/vfsif.h>
#include <assert.h>
#include <sys/param.h>
#include "puffs.h"
#include "puffs_priv.h"
#define GETDENTS_BUFSIZ 4096
static char getdents_buf[GETDENTS_BUFSIZ];
#define RW_BUFSIZ (128 << 10)
static char rw_buf[RW_BUFSIZ];
/*===========================================================================*
* fs_readwrite *
*===========================================================================*/
int fs_readwrite(void)
{
int r = OK, rw_flag;
cp_grant_id_t gid;
off_t pos;
size_t nrbytes, bytes_left, bytes_done = 0;
struct puffs_node *pn;
struct vattr va;
PUFFS_MAKECRED(pcr, &global_kcred);
if ((pn = puffs_pn_nodewalk(global_pu, 0, &fs_m_in.REQ_INODE_NR)) == NULL) {
lpuffs_debug("walk failed...\n");
return(EINVAL);
}
/* Get the values from the request message */
rw_flag = (fs_m_in.m_type == REQ_READ ? READING : WRITING);
gid = (cp_grant_id_t) fs_m_in.REQ_GRANT;
pos = (off_t) fs_m_in.REQ_SEEK_POS_LO;
nrbytes = bytes_left = (size_t) fs_m_in.REQ_NBYTES;
if (nrbytes > RW_BUFSIZ)
nrbytes = bytes_left = RW_BUFSIZ;
memset(getdents_buf, '\0', GETDENTS_BUFSIZ); /* Avoid leaking any data */
if (rw_flag == READING) {
if (global_pu->pu_ops.puffs_node_read == NULL)
return(EINVAL);
r = global_pu->pu_ops.puffs_node_read(global_pu, pn, (uint8_t *)rw_buf,
pos, &bytes_left, pcr, 0);
if (r) {
lpuffs_debug("puffs_node_read failed\n");
return(EINVAL);
}
bytes_done = nrbytes - bytes_left;
if (bytes_done) {
r = sys_safecopyto(VFS_PROC_NR, gid, (vir_bytes) 0,
(vir_bytes) rw_buf, bytes_done, D);
update_times(pn, ATIME, 0);
}
} else if (rw_flag == WRITING) {
/* At first try to change vattr */
if (global_pu->pu_ops.puffs_node_setattr == NULL)
return(EINVAL);
puffs_vattr_null(&va);
if ( (pos + bytes_left) > pn->pn_va.va_size)
va.va_size = bytes_left + pos;
va.va_ctime.tv_sec = va.va_mtime.tv_sec = clock_time();
va.va_atime.tv_sec = pn->pn_va.va_atime.tv_sec;
r = global_pu->pu_ops.puffs_node_setattr(global_pu, pn, &va, pcr);
if (r) return(EINVAL);
r = sys_safecopyfrom(VFS_PROC_NR, gid, (vir_bytes) 0,
(vir_bytes) rw_buf, nrbytes, D);
if (r != OK) return(EINVAL);
if (global_pu->pu_ops.puffs_node_write == NULL)
return(EINVAL);
r = global_pu->pu_ops.puffs_node_write(global_pu, pn, (uint8_t *)rw_buf,
pos, &bytes_left, pcr, 0);
bytes_done = nrbytes - bytes_left;
}
if (r != OK) return(EINVAL);
fs_m_out.RES_SEEK_POS_LO = pos + bytes_done;
fs_m_out.RES_NBYTES = bytes_done;
return(r);
}
/*===========================================================================*
* fs_breadwrite *
*===========================================================================*/
int fs_breadwrite(void)
{
/* We do not support breads/writes */
panic("bread write requested, but FS doesn't support it!\n");
return(OK);
}
/*===========================================================================*
* fs_getdents *
*===========================================================================*/
int fs_getdents(void)
{
int r;
register struct puffs_node *pn;
ino_t ino;
cp_grant_id_t gid;
size_t size, buf_left;
off_t pos;
struct dirent *dent;
int eofflag = 0;
size_t written;
PUFFS_MAKECRED(pcr, &global_kcred);
ino = (ino_t) fs_m_in.REQ_INODE_NR;
gid = (gid_t) fs_m_in.REQ_GRANT;
size = buf_left = (size_t) fs_m_in.REQ_MEM_SIZE;
pos = (off_t) fs_m_in.REQ_SEEK_POS_LO;
if ((pn = puffs_pn_nodewalk(global_pu, 0, &ino)) == NULL) {
lpuffs_debug("walk failed...\n");
return(EINVAL);
}
if (GETDENTS_BUFSIZ < size)
size = buf_left = GETDENTS_BUFSIZ;
memset(getdents_buf, '\0', GETDENTS_BUFSIZ); /* Avoid leaking any data */
dent = (struct dirent*) getdents_buf;
r = global_pu->pu_ops.puffs_node_readdir(global_pu, pn, dent, &pos,
&buf_left, pcr, &eofflag, 0, 0);
if (r) {
lpuffs_debug("puffs_node_readdir returned error\n");
return(EINVAL);
}
assert(buf_left <= size);
written = size - buf_left;
if (written == 0 && !eofflag) {
lpuffs_debug("The user's buffer is too small\n");
return(EINVAL);
}
if (written) {
r = sys_safecopyto(VFS_PROC_NR, gid, (vir_bytes) 0,
(vir_bytes) getdents_buf, written, D);
if (r != OK) return(r);
}
update_times(pn, ATIME, 0);
fs_m_out.RES_NBYTES = written;
fs_m_out.RES_SEEK_POS_LO = pos;
return(OK);
}