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/*
* Copyright (C) 1997 NCSA
* All rights reserved.
*
* Programmer: Robb Matzke <matzke@llnl.gov>
* Wednesday, October 22, 1997
*
* Purpose: This is the Posix section-2 I/O subclass of H5Flow.
*
* Notes: This driver keeps track of its own file position in order to
* minimize the number of calls to lseek(). We assume that
* opening a file sets the current file position to the beginning
* and that read() and write() modify the file position as
* expected when they return successfully (unsuccessful return
* leaves the file position undefined).
*/
#include <H5private.h>
#include <H5Eprivate.h>
#include <H5Fprivate.h>
#include <H5MMprivate.h>
#include <sys/types.h>
#include <sys/stat.h>
#define PABLO_MASK H5F_sec2
static hbool_t interface_initialize_g = FALSE;
#define INTERFACE_INIT NULL
static H5F_low_t *H5F_sec2_open(const char *name, uintn flags, H5F_search_t *);
static herr_t H5F_sec2_close(H5F_low_t *lf);
static herr_t H5F_sec2_read(H5F_low_t *lf, const haddr_t *addr, size_t size,
uint8 *buf);
static herr_t H5F_sec2_write(H5F_low_t *lf, const haddr_t *addr, size_t size,
const uint8 *buf);
const H5F_low_class_t H5F_LOW_SEC2[1] =
{
{
NULL, /* access method */
H5F_sec2_open, /* open method */
H5F_sec2_close, /* close method */
H5F_sec2_read, /* read method */
H5F_sec2_write, /* write method */
NULL, /* flush method */
NULL, /* extend method */
}};
/*-------------------------------------------------------------------------
* Function: H5F_sec2_open
*
* Purpose: Opens a file with name NAME. The FLAGS are a bit field with
* the possible values defined in H5F_low_open().
*
* Errors:
* IO CANTOPENFILE Open failed.
*
* Return: Success: Low-level file pointer
*
* Failure: NULL
*
* Programmer: Robb Matzke
* Wednesday, October 22, 1997
*
* Modifications:
*
*-------------------------------------------------------------------------
*/
static H5F_low_t *
H5F_sec2_open(const char *name, uintn flags, H5F_search_t *key /*out */ )
{
uintn oflags;
H5F_low_t *lf = NULL;
int fd;
struct stat sb;
FUNC_ENTER(H5F_sec2_open, NULL);
oflags = (flags & H5F_ACC_WRITE) ? O_RDWR : O_RDONLY;
oflags |= (flags & H5F_ACC_CREAT) ? O_CREAT : 0;
oflags |= (flags & H5F_ACC_EXCL) ? O_EXCL : 0;
oflags |= (flags & H5F_ACC_TRUNC) ? O_TRUNC : 0;
if ((fd = open(name, oflags, 0666)) < 0) {
HRETURN_ERROR(H5E_IO, H5E_CANTOPENFILE, NULL, "open failed");
}
lf = H5MM_xcalloc(1, sizeof(H5F_low_t));
lf->u.sec2.fd = fd;
lf->u.sec2.op = H5F_OP_SEEK;
lf->u.sec2.cur = 0;
fstat(fd, &sb);
lf->eof.offset = sb.st_size;
if (key) {
key->dev = sb.st_dev;
key->ino = sb.st_ino;
}
FUNC_LEAVE(lf);
}
/*-------------------------------------------------------------------------
* Function: H5F_sec2_close
*
* Purpose: Closes a file.
*
* Errors:
* IO CLOSEERROR Close failed.
*
* Return: Success: SUCCEED
*
* Failure: FAIL
*
* Programmer: Robb Matzke
* Wednesday, October 22, 1997
*
* Modifications:
*
*-------------------------------------------------------------------------
*/
static herr_t
H5F_sec2_close(H5F_low_t *lf)
{
FUNC_ENTER(H5F_sec2_close, FAIL);
if (close(lf->u.sec2.fd) < 0) {
HRETURN_ERROR(H5E_IO, H5E_CLOSEERROR, FAIL, "close failed");
}
lf->u.sec2.fd = -1;
FUNC_LEAVE(SUCCEED);
}
/*-------------------------------------------------------------------------
* Function: H5F_sec2_read
*
* Purpose: Reads SIZE bytes beginning at address ADDR in file LF and
* places them in buffer BUF. Reading past the logical or
* physical end of file returns zeros instead of failing.
*
* Errors:
* IO READERROR Read failed.
* IO SEEKERROR Lseek failed.
*
* Return: Success: SUCCEED
*
* Failure: FAIL
*
* Programmer: Robb Matzke
* Wednesday, October 22, 1997
*
* Modifications:
*
*-------------------------------------------------------------------------
*/
static herr_t
H5F_sec2_read(H5F_low_t *lf, const haddr_t *addr, size_t size, uint8 *buf)
{
ssize_t n;
off_t offset;
FUNC_ENTER(H5F_sec2_read, FAIL);
/* Check for overflow */
offset = addr->offset;
assert("address overflowed" && offset == addr->offset);
assert("overflow" && offset + size >= offset);
/* Check easy cases */
if (0 == size)
HRETURN(SUCCEED);
if (offset >= lf->eof.offset) {
HDmemset(buf, 0, size);
HRETURN(SUCCEED);
}
/*
* Optimize seeking. If that optimization is disabled then always call
* lseek().
*/
if (!H5F_OPT_SEEK ||
lf->u.sec2.op == H5F_OP_UNKNOWN ||
lf->u.sec2.cur != offset) {
if (lseek(lf->u.sec2.fd, offset, SEEK_SET) < 0) {
HRETURN_ERROR(H5E_IO, H5E_SEEKERROR, FAIL, "lseek failed");
}
lf->u.sec2.cur = offset;
}
/*
* Read zeros past the logical end of file (physical is handled below)
*/
if ((size_t) offset + size > lf->eof.offset) {
size_t nbytes = (size_t) offset + size - lf->eof.offset;
HDmemset(buf + size - nbytes, 0, nbytes);
size -= nbytes;
}
/*
* Read the data. If a read error occurs then set the last file operation
* to UNKNOWN because the file position isn't guaranteed by Posix.
*/
if ((n = read(lf->u.sec2.fd, buf, size)) < 0) {
lf->u.sec2.op = H5F_OP_UNKNOWN;
HRETURN_ERROR(H5E_IO, H5E_READERROR, FAIL, "read failed");
} else if (n < size) {
HDmemset(buf + n, 0, size - n);
}
/*
* Update the file position with the number of bytes actually read. This
* might be different than the number requested.
*/
lf->u.sec2.op = H5F_OP_READ;
lf->u.sec2.cur = offset + n;
assert("address overflowed" && lf->u.sec2.cur >= offset);
FUNC_LEAVE(SUCCEED);
}
/*-------------------------------------------------------------------------
* Function: H5F_sec2_write
*
* Purpose: Writes SIZE bytes from the beginning of BUF into file LF at
* file address ADDR.
*
* Errors:
* IO SEEKERROR Lseek failed.
* IO WRITEERROR Write failed.
*
* Return: Success: SUCCEED
*
* Failure: FAIL
*
* Programmer: Robb Matzke
* Wednesday, October 22, 1997
*
* Modifications:
*
*-------------------------------------------------------------------------
*/
static herr_t
H5F_sec2_write(H5F_low_t *lf, const haddr_t *addr, size_t size,
const uint8 *buf)
{
off_t offset;
FUNC_ENTER(H5F_sec2_write, FAIL);
/* Check for overflow */
offset = addr->offset;
assert("address overflowed" && offset == addr->offset);
assert("overflow" && offset + size >= offset);
/*
* Optimize seeking. If that optimization is disabled then always call
* lseek().
*/
if (!H5F_OPT_SEEK ||
lf->u.sec2.op == H5F_OP_UNKNOWN ||
lf->u.sec2.cur != offset) {
if (lseek(lf->u.sec2.fd, offset, SEEK_SET) < 0) {
HRETURN_ERROR(H5E_IO, H5E_SEEKERROR, FAIL, "lseek failed");
}
lf->u.sec2.cur = offset;
}
/*
* Write the data to the file. If the write failed then set the
* operation back to UNKNOWN since Posix doesn't gurantee its value.
*/
if (size != write(lf->u.sec2.fd, buf, size)) {
lf->u.sec2.op = H5F_OP_UNKNOWN;
HRETURN_ERROR(H5E_IO, H5E_WRITEERROR, FAIL, "write failed");
}
/*
* Update the file position.
*/
lf->u.sec2.op = H5F_OP_WRITE;
lf->u.sec2.cur = offset + size;
assert("address overflowed" && lf->u.sec2.cur >= offset);
FUNC_LEAVE(SUCCEED);
}
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