1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause 3 * 4 * Copyright (c) 2005-2008 Poul-Henning Kamp 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 * 28 * $FreeBSD$ 29 */ 30 31 #include <assert.h> 32 #include <errno.h> 33 #include <fcntl.h> 34 #include <stdlib.h> 35 #include <string.h> 36 #include <unistd.h> 37 #include <zlib.h> 38 39 #include <sys/disk.h> 40 #include <sys/endian.h> 41 #include <sys/stat.h> 42 43 #include "miniobj.h" 44 #include "fifolog.h" 45 #include "libfifolog_int.h" 46 47 /* 48 * Open a fifolog file or partition for reading or writing. 49 * 50 * Return value is NULL for success or a error description string to 51 * be augmented by errno if non-zero. 52 * 53 * The second function is just an error-handling wrapper around the 54 * first which, does the actual work. 55 */ 56 57 static const char * 58 fifolog_int_open_i(struct fifolog_file *f, const char *fname, int mode) 59 { 60 struct stat st; 61 ssize_t u; 62 int i; 63 64 f->fd = open(fname, mode ? O_RDWR : O_RDONLY); 65 if (f->fd < 0) 66 return ("Cannot open"); 67 68 /* Determine initial record size guesstimate */ 69 i = ioctl(f->fd, DIOCGSECTORSIZE, &f->recsize); 70 if (i != 0 && errno != ENOTTY) 71 return ("ioctl(DIOCGSECTORSIZE) failed"); 72 73 if (i != 0) { 74 i = fstat(f->fd, &st); 75 assert(i == 0); 76 if (!S_ISREG(st.st_mode)) 77 return ("Neither disk nor regular file"); 78 f->recsize = 512; 79 f->logsize = st.st_size; 80 } else if (f->recsize < 64) { 81 return ("Disk device sectorsize smaller than 64"); 82 } else { 83 i = ioctl(f->fd, DIOCGMEDIASIZE, &f->logsize); 84 if (i < 0 && errno != ENOTTY) 85 return ("ioctl(DIOCGMEDIASIZE) failed"); 86 } 87 88 /* Allocate a record buffer */ 89 f->recbuf = malloc(f->recsize); 90 if (f->recbuf == NULL) 91 return ("Cannot malloc"); 92 93 /* Read and validate the label sector */ 94 i = pread(f->fd, f->recbuf, f->recsize, 0); 95 if (i < 0 || i < (int)f->recsize) 96 return ("Read error, first sector"); 97 98 errno = 0; 99 if (memcmp(f->recbuf, FIFOLOG_FMT_MAGIC, strlen(FIFOLOG_FMT_MAGIC) + 1)) 100 return ("Wrong or missing magic string"); 101 102 u = be32dec(f->recbuf + FIFOLOG_OFF_BS); 103 if (u < 64) 104 return ("Wrong record size in header (<64)"); 105 106 if ((off_t)u >= f->logsize) 107 return ("Record size in header bigger than fifolog"); 108 109 f->recsize = u; 110 111 /* Reallocate the buffer to correct size if necessary */ 112 if (u != f->recsize) { 113 free(f->recbuf); 114 f->recbuf = NULL; 115 f->recsize = u; 116 f->recbuf = malloc(f->recsize); 117 if (f->recbuf == NULL) 118 return ("Cannot malloc"); 119 } 120 121 /* Calculate number of records in fifolog */ 122 f->logsize /= u; 123 if (f->logsize < 10) 124 return ("less than 10 records in fifolog"); 125 126 f->logsize--; /* the label record */ 127 128 /* Initialize zlib handling */ 129 130 f->zs = calloc(1, sizeof(*f->zs)); 131 if (f->zs == NULL) 132 return ("cannot malloc"); 133 134 return (NULL); 135 } 136 137 const char * 138 fifolog_int_open(struct fifolog_file **ff, const char *fname, int mode) 139 { 140 struct fifolog_file fs, *f; 141 const char *retval; 142 int e; 143 144 f = &fs; 145 memset(f, 0, sizeof *f); 146 f->fd = -1; 147 retval = fifolog_int_open_i(f, fname, mode); 148 e = errno; 149 if (retval == NULL) { 150 *ff = malloc(sizeof *f); 151 if (*ff != NULL) { 152 memcpy(*ff, f, sizeof *f); 153 (*ff)->magic = FIFOLOG_FILE_MAGIC; 154 return (retval); 155 } 156 } 157 fifolog_int_close(&f); 158 errno = e; 159 return (retval); 160 } 161 162 void 163 fifolog_int_close(struct fifolog_file **ff) 164 { 165 struct fifolog_file *f; 166 167 f = *ff; 168 *ff = NULL; 169 if (f == NULL) 170 return; 171 172 if (f->fd >= 0) 173 (void)close(f->fd); 174 if (f->zs != NULL) 175 free(f->zs); 176 if (f->recbuf != NULL) 177 free(f->recbuf); 178 } 179 180 static void 181 fifolog_int_file_assert(const struct fifolog_file *ff) 182 { 183 184 CHECK_OBJ_NOTNULL(ff, FIFOLOG_FILE_MAGIC); 185 assert(ff->fd >= 0); 186 assert(ff->recbuf != NULL); 187 } 188 189 190 /* 191 * Read a record. 192 * 193 * Return zero on success 194 */ 195 196 int 197 fifolog_int_read(const struct fifolog_file *ff, off_t recno) 198 { 199 int i; 200 201 fifolog_int_file_assert(ff); 202 if (recno >= ff->logsize) 203 return (-1); 204 recno++; /* label sector */ 205 i = pread(ff->fd, ff->recbuf, ff->recsize, recno * ff->recsize); 206 if (i < 0) 207 return (-2); 208 if (i != (int)ff->recsize) 209 return (-3); 210 return (0); 211 } 212 213 /* 214 * Find the last written record in the fifolog. 215 * 216 * Return is error string or NULL on success 217 */ 218 219 const char * 220 fifolog_int_findend(const struct fifolog_file *ff, off_t *last) 221 { 222 off_t o, s; 223 int e; 224 unsigned seq0, seq; 225 226 fifolog_int_file_assert(ff); 227 228 o = 0; 229 e = fifolog_int_read(ff, o); 230 if (e) 231 return("Read error, first record"); 232 233 seq0 = be32dec(ff->recbuf); 234 235 /* If the first records sequence is zero, the fifolog is empty */ 236 if (seq0 == 0) { 237 *last = o; 238 return (NULL); 239 } 240 241 /* Do a binary search for a discontinuity in the sequence numbers */ 242 s = ff->logsize / 2; 243 do { 244 e = fifolog_int_read(ff, o + s); 245 if (e) 246 return ("Read error while searching"); 247 seq = be32dec(ff->recbuf); 248 if (seq == seq0 + s) { 249 o += s; 250 seq0 = seq; 251 } 252 s /= 2; 253 assert(o < ff->logsize); 254 } while (s > 0); 255 256 *last = o; 257 return (NULL); 258 } 259