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/*-
* Copyright (c) 2005-2008 Poul-Henning Kamp
* 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.
*
* $FreeBSD$
*/
#include <assert.h>
#include <errno.h>
#include <fcntl.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <zlib.h>
#include <sys/disk.h>
#include <sys/endian.h>
#include <sys/stat.h>
#include "miniobj.h"
#include "fifolog.h"
#include "libfifolog_int.h"
/*
* Open a fifolog file or partition for reading or writing.
*
* Return value is NULL for success or a error description string to
* be augmented by errno if non-zero.
*
* The second function is just an error-handling wrapper around the
* first which, does the actual work.
*/
static const char *
fifolog_int_open_i(struct fifolog_file *f, const char *fname, int mode)
{
struct stat st;
ssize_t u;
int i;
f->fd = open(fname, mode ? O_RDWR : O_RDONLY);
if (f->fd < 0)
return ("Cannot open");
/* Determine initial record size guesstimate */
i = ioctl(f->fd, DIOCGSECTORSIZE, &f->recsize);
if (i != 0 && errno != ENOTTY)
return ("ioctl(DIOCGSECTORSIZE) failed");
if (i != 0) {
i = fstat(f->fd, &st);
assert(i == 0);
if (!S_ISREG(st.st_mode))
return ("Neither disk nor regular file");
f->recsize = 512;
f->logsize = st.st_size;
} else if (f->recsize < 64) {
return ("Disk device sectorsize smaller than 64");
} else {
i = ioctl(f->fd, DIOCGMEDIASIZE, &f->logsize);
if (i < 0 && errno != ENOTTY)
return ("ioctl(DIOCGMEDIASIZE) failed");
}
/* Allocate a record buffer */
f->recbuf = malloc(f->recsize);
if (f->recbuf == NULL)
return ("Cannot malloc");
/* Read and validate the label sector */
i = pread(f->fd, f->recbuf, f->recsize, 0);
if (i < 0 || i < (int)f->recsize)
return ("Read error, first sector");
errno = 0;
if (memcmp(f->recbuf, FIFOLOG_FMT_MAGIC, strlen(FIFOLOG_FMT_MAGIC) + 1))
return ("Wrong or missing magic string");
u = be32dec(f->recbuf + FIFOLOG_OFF_BS);
if (u < 64)
return ("Wrong record size in header (<64)");
if ((off_t)u >= f->logsize)
return ("Record size in header bigger than fifolog");
f->recsize = u;
/* Reallocate the buffer to correct size if necessary */
if (u != f->recsize) {
free(f->recbuf);
f->recbuf = NULL;
f->recsize = u;
f->recbuf = malloc(f->recsize);
if (f->recbuf == NULL)
return ("Cannot malloc");
}
/* Calculate number of records in fifolog */
f->logsize /= u;
if (f->logsize < 10)
return ("less than 10 records in fifolog");
f->logsize--; /* the label record */
/* Initialize zlib handling */
f->zs = calloc(1, sizeof(*f->zs));
if (f->zs == NULL)
return ("cannot malloc");
return (NULL);
}
const char *
fifolog_int_open(struct fifolog_file **ff, const char *fname, int mode)
{
struct fifolog_file fs, *f;
const char *retval;
int e;
f = &fs;
memset(f, 0, sizeof *f);
f->fd = -1;
retval = fifolog_int_open_i(f, fname, mode);
e = errno;
if (retval == NULL) {
*ff = malloc(sizeof *f);
if (*ff != NULL) {
memcpy(*ff, f, sizeof *f);
(*ff)->magic = FIFOLOG_FILE_MAGIC;
return (retval);
}
}
fifolog_int_close(&f);
errno = e;
return (retval);
}
void
fifolog_int_close(struct fifolog_file **ff)
{
struct fifolog_file *f;
f = *ff;
*ff = NULL;
if (f == NULL)
return;
if (f->fd >= 0)
(void)close(f->fd);
if (f->zs != NULL)
free(f->zs);
if (f->recbuf != NULL)
free(f->recbuf);
}
static void
fifolog_int_file_assert(const struct fifolog_file *ff)
{
CHECK_OBJ_NOTNULL(ff, FIFOLOG_FILE_MAGIC);
assert(ff->fd >= 0);
assert(ff->recbuf != NULL);
}
/*
* Read a record.
*
* Return zero on success
*/
int
fifolog_int_read(const struct fifolog_file *ff, off_t recno)
{
int i;
fifolog_int_file_assert(ff);
if (recno >= ff->logsize)
return (-1);
recno++; /* label sector */
i = pread(ff->fd, ff->recbuf, ff->recsize, recno * ff->recsize);
if (i < 0)
return (-2);
if (i != (int)ff->recsize)
return (-3);
return (0);
}
/*
* Find the last written record in the fifolog.
*
* Return is error string or NULL on success
*/
const char *
fifolog_int_findend(const struct fifolog_file *ff, off_t *last)
{
off_t o, s;
int e;
unsigned seq0, seq;
fifolog_int_file_assert(ff);
o = 0;
e = fifolog_int_read(ff, o);
if (e)
return("Read error, first record");
seq0 = be32dec(ff->recbuf);
/* If the first records sequence is zero, the fifolog is empty */
if (seq0 == 0) {
*last = o;
return (NULL);
}
/* Do a binary search for a discontinuity in the sequence numbers */
s = ff->logsize / 2;
do {
e = fifolog_int_read(ff, o + s);
if (e)
return ("Read error while searching");
seq = be32dec(ff->recbuf);
if (seq == seq0 + s) {
o += s;
seq0 = seq;
}
s /= 2;
assert(o < ff->logsize);
} while (s > 0);
*last = o;
return (NULL);
}
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