minix/lib/libpuffs/read.c

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4.1 KiB
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/* Created (MFS based):
* February 2010 (Evgeniy Ivanov)
*/
#include "fs.h"
#include <stddef.h>
#include <string.h>
#include <stdlib.h>
#include <dirent.h>
#include <assert.h>
#include <sys/param.h>
#include "puffs.h"
#include "puffs_priv.h"
#define GETDENTS_BUFSIZ 4096
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static char getdents_buf[GETDENTS_BUFSIZ];
#define RW_BUFSIZ (128 * 1024)
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static char rw_buf[RW_BUFSIZ];
/*===========================================================================*
* fs_read *
*===========================================================================*/
ssize_t fs_read(ino_t ino_nr, struct fsdriver_data *data, size_t bytes,
off_t pos, int call)
{
int r;
size_t bytes_left, bytes_done;
struct puffs_node *pn;
PUFFS_MAKECRED(pcr, &global_kcred);
if ((pn = puffs_pn_nodewalk(global_pu, 0, &ino_nr)) == NULL) {
lpuffs_debug("walk failed...\n");
return(EINVAL);
}
if (bytes > sizeof(rw_buf))
bytes = sizeof(rw_buf);
bytes_left = bytes;
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 = bytes - bytes_left;
if (bytes_done > 0) {
if ((r = fsdriver_copyout(data, 0, rw_buf, bytes_done)) != OK)
return r;
update_timens(pn, ATIME, NULL);
}
return (ssize_t)bytes_done;
}
/*===========================================================================*
* fs_write *
*===========================================================================*/
ssize_t fs_write(ino_t ino_nr, struct fsdriver_data *data, size_t bytes,
off_t pos, int call)
{
int r;
size_t bytes_left;
struct puffs_node *pn;
struct vattr va;
struct timespec cur_time;
PUFFS_MAKECRED(pcr, &global_kcred);
if ((pn = puffs_pn_nodewalk(global_pu, 0, &ino_nr)) == NULL) {
lpuffs_debug("walk failed...\n");
return(EINVAL);
}
if (bytes > sizeof(rw_buf))
bytes = sizeof(rw_buf);
bytes_left = bytes;
/* At first try to change vattr */
if (global_pu->pu_ops.puffs_node_setattr == NULL)
return(EINVAL);
(void)clock_time(&cur_time);
puffs_vattr_null(&va);
if ((u_quad_t)(pos + bytes_left) > pn->pn_va.va_size)
va.va_size = bytes_left + pos;
va.va_ctime = va.va_mtime = cur_time;
va.va_atime = pn->pn_va.va_atime;
r = global_pu->pu_ops.puffs_node_setattr(global_pu, pn, &va, pcr);
if (r) return(EINVAL);
if ((r = fsdriver_copyin(data, 0, rw_buf, bytes)) != OK)
return r;
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);
if (r != OK) return(EINVAL);
return (ssize_t)(bytes - bytes_left);
}
/*===========================================================================*
* fs_getdents *
*===========================================================================*/
ssize_t fs_getdents(ino_t ino_nr, struct fsdriver_data *data, size_t bytes,
off_t *pos)
{
int r;
register struct puffs_node *pn;
size_t buf_left, written;
struct dirent *dent;
int eofflag = 0;
PUFFS_MAKECRED(pcr, &global_kcred);
if ((pn = puffs_pn_nodewalk(global_pu, 0, &ino_nr)) == NULL) {
lpuffs_debug("walk failed...\n");
return(EINVAL);
}
if (bytes > sizeof(getdents_buf))
bytes = sizeof(getdents_buf);
memset(getdents_buf, 0, sizeof(getdents_buf)); /* Avoid leaking any data */
buf_left = bytes;
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 <= bytes);
written = bytes - buf_left;
if (written == 0 && !eofflag) {
lpuffs_debug("The user's buffer is too small\n");
return(EINVAL);
}
if (written) {
if ((r = fsdriver_copyout(data, 0, getdents_buf, written)) != OK)
return r;
}
update_timens(pn, ATIME, NULL);
/* The puffs readdir call has already updated the position. */
return written;
}