FreeBSD-5.3/lib/libstand/splitfs.c
/*
* Copyright (c) 2002 Maxim Sobolev
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD: src/lib/libstand/splitfs.c,v 1.6 2004/01/21 20:12:23 jhb Exp $");
#include "stand.h"
#define NTRIES (3)
#define CONF_BUF (512)
#define SEEK_BUF (512)
struct split_file
{
char **filesv; /* Filenames */
char **descsv; /* Descriptions */
int filesc; /* Number of parts */
int curfile; /* Current file number */
int curfd; /* Current file descriptor */
off_t tot_pos; /* Offset from the beginning of the sequence */
off_t file_pos; /* Offset from the beginning of the slice */
};
static int split_openfile(struct split_file *sf);
static int splitfs_open(const char *path, struct open_file *f);
static int splitfs_close(struct open_file *f);
static int splitfs_read(struct open_file *f, void *buf, size_t size, size_t *resid);
static off_t splitfs_seek(struct open_file *f, off_t offset, int where);
static int splitfs_stat(struct open_file *f, struct stat *sb);
struct fs_ops splitfs_fsops = {
"split",
splitfs_open,
splitfs_close,
splitfs_read,
null_write,
splitfs_seek,
splitfs_stat,
null_readdir
};
static void
split_file_destroy(struct split_file *sf)
{
int i;
if (sf->filesc > 0) {
for (i = 0; i < sf->filesc; i++) {
free(sf->filesv[i]);
free(sf->descsv[i]);
}
free(sf->filesv);
free(sf->descsv);
}
free(sf);
}
static int
split_openfile(struct split_file *sf)
{
int i;
for (i = 0;; i++) {
sf->curfd = open(sf->filesv[sf->curfile], O_RDONLY);
if (sf->curfd >= 0)
break;
if ((sf->curfd == -1) && (errno != ENOENT))
return (errno);
if (i == NTRIES)
return (EIO);
printf("\nInsert disk labelled %s and press any key...",
sf->descsv[sf->curfile]);
getchar();
putchar('\n');
}
sf->file_pos = 0;
return (0);
}
static int
splitfs_open(const char *fname, struct open_file *f)
{
char *buf, *confname, *cp;
int conffd;
struct split_file *sf;
struct stat sb;
/* Have to be in "just read it" mode */
if (f->f_flags != F_READ)
return(EPERM);
/* If the name already ends in `.split', ignore it */
if ((cp = strrchr(fname, '.')) && (!strcmp(cp, ".split")))
return(ENOENT);
/* Construct new name */
confname = malloc(strlen(fname) + 7);
sprintf(confname, "%s.split", fname);
/* Try to open the configuration file */
conffd = open(confname, O_RDONLY);
free(confname);
if (conffd == -1)
return(ENOENT);
if (fstat(conffd, &sb) < 0) {
printf("splitfs_open: stat failed\n");
close(conffd);
return(ENOENT);
}
if (!S_ISREG(sb.st_mode)) {
printf("splitfs_open: not a file\n");
close(conffd);
return(EISDIR); /* best guess */
}
/* Allocate a split_file structure, populate it from the config file */
sf = malloc(sizeof(struct split_file));
bzero(sf, sizeof(struct split_file));
buf = malloc(CONF_BUF);
while (fgetstr(buf, CONF_BUF, conffd) > 0) {
cp = buf;
while ((*cp != '\0') && (isspace(*cp) == 0))
cp++;
if (*cp != '\0') {
*cp = '\0';
cp++;
}
while ((*cp != '\0') && (isspace(*cp) != 0))
cp++;
if (*cp == '\0')
cp = buf;
sf->filesc++;
sf->filesv = realloc(sf->filesv, sizeof(*(sf->filesv)) * sf->filesc);
sf->descsv = realloc(sf->descsv, sizeof(*(sf->descsv)) * sf->filesc);
sf->filesv[sf->filesc - 1] = strdup(buf);
sf->descsv[sf->filesc - 1] = strdup(cp);
}
free(buf);
close(conffd);
if (sf->filesc == 0) {
split_file_destroy(sf);
return(ENOENT);
}
errno = split_openfile(sf);
if (errno != 0) {
split_file_destroy(sf);
return(ENOENT);
}
/* Looks OK, we'll take it */
f->f_fsdata = sf;
return (0);
}
static int
splitfs_close(struct open_file *f)
{
int fd;
struct split_file *sf;
sf = (struct split_file *)f->f_fsdata;
fd = sf->curfd;
split_file_destroy(sf);
return(close(fd));
}
static int
splitfs_read(struct open_file *f, void *buf, size_t size, size_t *resid)
{
int i, nread, totread;
struct split_file *sf;
sf = (struct split_file *)f->f_fsdata;
totread = 0;
do {
nread = read(sf->curfd, buf, size - totread);
/* Error? */
if (nread == -1)
return (errno);
sf->tot_pos += nread;
sf->file_pos += nread;
totread += nread;
buf += nread;
if (totread < size) { /* EOF */
if (sf->curfile == (sf->filesc - 1)) /* Last slice */
break;
/* Close previous slice */
if (close(sf->curfd) != 0)
return (errno);
sf->curfile++;
errno = split_openfile(sf);
if (errno)
return (errno);
}
} while (totread < size);
if (resid != NULL)
*resid = size - totread;
return (0);
}
static off_t
splitfs_seek(struct open_file *f, off_t offset, int where)
{
int nread;
size_t resid;
off_t new_pos, seek_by;
struct split_file *sf;
sf = (struct split_file *)f->f_fsdata;
seek_by = offset;
switch (where) {
case SEEK_SET:
seek_by -= sf->tot_pos;
break;
case SEEK_CUR:
break;
case SEEK_END:
panic("splitfs_seek: SEEK_END not supported");
break;
default:
errno = EINVAL;
return (-1);
}
if (seek_by > 0) {
/*
* Seek forward - implemented using splitfs_read(), because otherwise we'll be
* unable to detect that we have crossed slice boundary and hence
* unable to do a long seek crossing that boundary.
*/
void *tmp;
tmp = malloc(SEEK_BUF);
if (tmp == NULL) {
errno = ENOMEM;
return (-1);
}
nread = 0;
for (; seek_by > 0; seek_by -= nread) {
resid = 0;
errno = splitfs_read(f, tmp, min(seek_by, SEEK_BUF), &resid);
nread = min(seek_by, SEEK_BUF) - resid;
if ((errno != 0) || (nread == 0))
/* Error or EOF */
break;
}
free(tmp);
if (errno != 0)
return (-1);
}
if (seek_by != 0) {
/* Seek backward or seek past the boundary of the last slice */
if (sf->file_pos + seek_by < 0)
panic("splitfs_seek: can't seek past the beginning of the slice");
new_pos = lseek(sf->curfd, seek_by, SEEK_CUR);
if (new_pos < 0) {
errno = EINVAL;
return (-1);
}
sf->tot_pos += new_pos - sf->file_pos;
sf->file_pos = new_pos;
}
return (sf->tot_pos);
}
static int
splitfs_stat(struct open_file *f, struct stat *sb)
{
int result;
struct split_file *sf = (struct split_file *)f->f_fsdata;
/* stat as normal, but indicate that size is unknown */
if ((result = fstat(sf->curfd, sb)) == 0)
sb->st_size = -1;
return (result);
}