minix3/lib/libhgfs/file.c

175 lines
4.7 KiB
C

/* Part of libhgfs - (c) 2009, D.C. van Moolenbroek */
#include "inc.h"
#include <fcntl.h>
#include <sys/stat.h>
/*===========================================================================*
* hgfs_open *
*===========================================================================*/
int hgfs_open(
char *path, /* path name to open */
int flags, /* open flags to use */
int mode, /* mode to create (user bits only) */
sffs_file_t *handle /* place to store resulting handle */
)
{
/* Open a file. Store a file handle upon success.
*/
int r, type;
/* We could implement this, but that means we would have to start tracking
* open files in order to associate data with them. Rather not.
*/
if (flags & O_APPEND) return EINVAL;
if (flags & O_CREAT) {
if (flags & O_EXCL) type = HGFS_OPEN_TYPE_C;
else if (flags & O_TRUNC) type = HGFS_OPEN_TYPE_COT;
else type = HGFS_OPEN_TYPE_CO;
} else {
if (flags & O_TRUNC) type = HGFS_OPEN_TYPE_OT;
else type = HGFS_OPEN_TYPE_O;
}
RPC_REQUEST(HGFS_REQ_OPEN);
RPC_NEXT32 = (flags & O_ACCMODE);
RPC_NEXT32 = type;
RPC_NEXT8 = HGFS_MODE_TO_PERM(mode);
path_put(path);
if ((r = rpc_query()) != OK)
return r;
*handle = (sffs_file_t)RPC_NEXT32;
return OK;
}
/*===========================================================================*
* hgfs_read *
*===========================================================================*/
ssize_t hgfs_read(
sffs_file_t handle, /* handle to open file */
char *buf, /* data buffer or NULL */
size_t size, /* maximum number of bytes to read */
u64_t off /* file offset */
)
{
/* Read from an open file. Upon success, return the number of bytes read.
*/
int r, len, max;
RPC_REQUEST(HGFS_REQ_READ);
RPC_NEXT32 = (u32_t)handle;
RPC_NEXT32 = ex64lo(off);
RPC_NEXT32 = ex64hi(off);
max = RPC_BUF_SIZE - RPC_LEN - sizeof(u32_t);
RPC_NEXT32 = (size < max) ? size : max;
if ((r = rpc_query()) != OK)
return r;
len = RPC_NEXT32;
if (len > max) len = max; /* sanity check */
/* Only copy out data if we're not operating directly on the RPC buffer. */
if (buf != RPC_PTR)
memcpy(buf, RPC_PTR, len);
return len;
}
/*===========================================================================*
* hgfs_write *
*===========================================================================*/
ssize_t hgfs_write(
sffs_file_t handle, /* handle to open file */
char *buf, /* data buffer or NULL */
size_t len, /* number of bytes to write */
u64_t off /* file offset */
)
{
/* Write to an open file. Upon success, return the number of bytes written.
*/
int r;
RPC_REQUEST(HGFS_REQ_WRITE);
RPC_NEXT32 = (u32_t)handle;
RPC_NEXT8 = 0; /* append flag */
RPC_NEXT32 = ex64lo(off);
RPC_NEXT32 = ex64hi(off);
RPC_NEXT32 = len;
/* Only copy in data if we're not operating directly on the RPC buffer. */
if (RPC_PTR != buf)
memcpy(RPC_PTR, buf, len);
RPC_ADVANCE(len);
if ((r = rpc_query()) != OK)
return r;
return RPC_NEXT32;
}
/*===========================================================================*
* hgfs_close *
*===========================================================================*/
int hgfs_close(
sffs_file_t handle /* handle to open file */
)
{
/* Close an open file.
*/
RPC_REQUEST(HGFS_REQ_CLOSE);
RPC_NEXT32 = (u32_t)handle;
return rpc_query();
}
/*===========================================================================*
* hgfs_readbuf *
*===========================================================================*/
size_t hgfs_readbuf(char **ptr)
{
/* Return information about the read buffer, for zero-copy purposes. Store a
* pointer to the first byte of the read buffer, and return the maximum data
* size. The results are static, but must only be used directly prior to a
* hgfs_read() call (with a NULL data buffer address).
*/
u32_t off;
off = RPC_HDR_SIZE + sizeof(u32_t);
RPC_RESET;
RPC_ADVANCE(off);
*ptr = RPC_PTR;
return RPC_BUF_SIZE - off;
}
/*===========================================================================*
* hgfs_writebuf *
*===========================================================================*/
size_t hgfs_writebuf(char **ptr)
{
/* Return information about the write buffer, for zero-copy purposes. Store a
* pointer to the first byte of the write buffer, and return the maximum data
* size. The results are static, but must only be used immediately after a
* hgfs_write() call (with a NULL data buffer address).
*/
u32_t off;
off = RPC_HDR_SIZE + sizeof(u32_t) + sizeof(u8_t) + sizeof(u32_t) * 3;
RPC_RESET;
RPC_ADVANCE(off);
*ptr = RPC_PTR;
return RPC_BUF_SIZE - off;
}