Mercurial > hg > CbC > CbC_gcc
annotate zlib/examples/gzlog.c @ 111:04ced10e8804
gcc 7
| author | kono |
|---|---|
| date | Fri, 27 Oct 2017 22:46:09 +0900 |
| parents | ae3a4bfb450b |
| children |
| rev | line source |
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1 /* |
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2 * gzlog.c |
| 111 | 3 * Copyright (C) 2004, 2008, 2012, 2016 Mark Adler, all rights reserved |
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4 * For conditions of distribution and use, see copyright notice in gzlog.h |
| 111 | 5 * version 2.2, 14 Aug 2012 |
| 6 */ | |
| 7 | |
| 8 /* | |
| 9 gzlog provides a mechanism for frequently appending short strings to a gzip | |
| 10 file that is efficient both in execution time and compression ratio. The | |
| 11 strategy is to write the short strings in an uncompressed form to the end of | |
| 12 the gzip file, only compressing when the amount of uncompressed data has | |
| 13 reached a given threshold. | |
| 14 | |
| 15 gzlog also provides protection against interruptions in the process due to | |
| 16 system crashes. The status of the operation is recorded in an extra field | |
| 17 in the gzip file, and is only updated once the gzip file is brought to a | |
| 18 valid state. The last data to be appended or compressed is saved in an | |
| 19 auxiliary file, so that if the operation is interrupted, it can be completed | |
| 20 the next time an append operation is attempted. | |
| 21 | |
| 22 gzlog maintains another auxiliary file with the last 32K of data from the | |
| 23 compressed portion, which is preloaded for the compression of the subsequent | |
| 24 data. This minimizes the impact to the compression ratio of appending. | |
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25 */ |
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26 |
| 111 | 27 /* |
| 28 Operations Concept: | |
| 29 | |
| 30 Files (log name "foo"): | |
| 31 foo.gz -- gzip file with the complete log | |
| 32 foo.add -- last message to append or last data to compress | |
| 33 foo.dict -- dictionary of the last 32K of data for next compression | |
| 34 foo.temp -- temporary dictionary file for compression after this one | |
| 35 foo.lock -- lock file for reading and writing the other files | |
| 36 foo.repairs -- log file for log file recovery operations (not compressed) | |
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37 |
| 111 | 38 gzip file structure: |
| 39 - fixed-length (no file name) header with extra field (see below) | |
| 40 - compressed data ending initially with empty stored block | |
| 41 - uncompressed data filling out originally empty stored block and | |
| 42 subsequent stored blocks as needed (16K max each) | |
| 43 - gzip trailer | |
| 44 - no junk at end (no other gzip streams) | |
| 45 | |
| 46 When appending data, the information in the first three items above plus the | |
| 47 foo.add file are sufficient to recover an interrupted append operation. The | |
| 48 extra field has the necessary information to restore the start of the last | |
| 49 stored block and determine where to append the data in the foo.add file, as | |
| 50 well as the crc and length of the gzip data before the append operation. | |
| 51 | |
| 52 The foo.add file is created before the gzip file is marked for append, and | |
| 53 deleted after the gzip file is marked as complete. So if the append | |
| 54 operation is interrupted, the data to add will still be there. If due to | |
| 55 some external force, the foo.add file gets deleted between when the append | |
| 56 operation was interrupted and when recovery is attempted, the gzip file will | |
| 57 still be restored, but without the appended data. | |
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58 |
| 111 | 59 When compressing data, the information in the first two items above plus the |
| 60 foo.add file are sufficient to recover an interrupted compress operation. | |
| 61 The extra field has the necessary information to find the end of the | |
| 62 compressed data, and contains both the crc and length of just the compressed | |
| 63 data and of the complete set of data including the contents of the foo.add | |
| 64 file. | |
| 65 | |
| 66 Again, the foo.add file is maintained during the compress operation in case | |
| 67 of an interruption. If in the unlikely event the foo.add file with the data | |
| 68 to be compressed is missing due to some external force, a gzip file with | |
| 69 just the previous compressed data will be reconstructed. In this case, all | |
| 70 of the data that was to be compressed is lost (approximately one megabyte). | |
| 71 This will not occur if all that happened was an interruption of the compress | |
| 72 operation. | |
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73 |
| 111 | 74 The third state that is marked is the replacement of the old dictionary with |
| 75 the new dictionary after a compress operation. Once compression is | |
| 76 complete, the gzip file is marked as being in the replace state. This | |
| 77 completes the gzip file, so an interrupt after being so marked does not | |
| 78 result in recompression. Then the dictionary file is replaced, and the gzip | |
| 79 file is marked as completed. This state prevents the possibility of | |
| 80 restarting compression with the wrong dictionary file. | |
| 81 | |
| 82 All three operations are wrapped by a lock/unlock procedure. In order to | |
| 83 gain exclusive access to the log files, first a foo.lock file must be | |
| 84 exclusively created. When all operations are complete, the lock is | |
| 85 released by deleting the foo.lock file. If when attempting to create the | |
| 86 lock file, it already exists and the modify time of the lock file is more | |
| 87 than five minutes old (set by the PATIENCE define below), then the old | |
| 88 lock file is considered stale and deleted, and the exclusive creation of | |
| 89 the lock file is retried. To assure that there are no false assessments | |
| 90 of the staleness of the lock file, the operations periodically touch the | |
| 91 lock file to update the modified date. | |
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92 |
| 111 | 93 Following is the definition of the extra field with all of the information |
| 94 required to enable the above append and compress operations and their | |
| 95 recovery if interrupted. Multi-byte values are stored little endian | |
| 96 (consistent with the gzip format). File pointers are eight bytes long. | |
| 97 The crc's and lengths for the gzip trailer are four bytes long. (Note that | |
| 98 the length at the end of a gzip file is used for error checking only, and | |
| 99 for large files is actually the length modulo 2^32.) The stored block | |
| 100 length is two bytes long. The gzip extra field two-byte identification is | |
| 101 "ap" for append. It is assumed that writing the extra field to the file is | |
| 102 an "atomic" operation. That is, either all of the extra field is written | |
| 103 to the file, or none of it is, if the operation is interrupted right at the | |
| 104 point of updating the extra field. This is a reasonable assumption, since | |
| 105 the extra field is within the first 52 bytes of the file, which is smaller | |
| 106 than any expected block size for a mass storage device (usually 512 bytes or | |
| 107 larger). | |
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108 |
| 111 | 109 Extra field (35 bytes): |
| 110 - Pointer to first stored block length -- this points to the two-byte length | |
| 111 of the first stored block, which is followed by the two-byte, one's | |
| 112 complement of that length. The stored block length is preceded by the | |
| 113 three-bit header of the stored block, which is the actual start of the | |
| 114 stored block in the deflate format. See the bit offset field below. | |
| 115 - Pointer to the last stored block length. This is the same as above, but | |
| 116 for the last stored block of the uncompressed data in the gzip file. | |
| 117 Initially this is the same as the first stored block length pointer. | |
| 118 When the stored block gets to 16K (see the MAX_STORE define), then a new | |
| 119 stored block as added, at which point the last stored block length pointer | |
| 120 is different from the first stored block length pointer. When they are | |
| 121 different, the first bit of the last stored block header is eight bits, or | |
| 122 one byte back from the block length. | |
| 123 - Compressed data crc and length. This is the crc and length of the data | |
| 124 that is in the compressed portion of the deflate stream. These are used | |
| 125 only in the event that the foo.add file containing the data to compress is | |
| 126 lost after a compress operation is interrupted. | |
| 127 - Total data crc and length. This is the crc and length of all of the data | |
| 128 stored in the gzip file, compressed and uncompressed. It is used to | |
| 129 reconstruct the gzip trailer when compressing, as well as when recovering | |
| 130 interrupted operations. | |
| 131 - Final stored block length. This is used to quickly find where to append, | |
| 132 and allows the restoration of the original final stored block state when | |
| 133 an append operation is interrupted. | |
| 134 - First stored block start as the number of bits back from the final stored | |
| 135 block first length byte. This value is in the range of 3..10, and is | |
| 136 stored as the low three bits of the final byte of the extra field after | |
| 137 subtracting three (0..7). This allows the last-block bit of the stored | |
| 138 block header to be updated when a new stored block is added, for the case | |
| 139 when the first stored block and the last stored block are the same. (When | |
| 140 they are different, the numbers of bits back is known to be eight.) This | |
| 141 also allows for new compressed data to be appended to the old compressed | |
| 142 data in the compress operation, overwriting the previous first stored | |
| 143 block, or for the compressed data to be terminated and a valid gzip file | |
| 144 reconstructed on the off chance that a compression operation was | |
| 145 interrupted and the data to compress in the foo.add file was deleted. | |
| 146 - The operation in process. This is the next two bits in the last byte (the | |
| 147 bits under the mask 0x18). The are interpreted as 0: nothing in process, | |
| 148 1: append in process, 2: compress in process, 3: replace in process. | |
| 149 - The top three bits of the last byte in the extra field are reserved and | |
| 150 are currently set to zero. | |
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151 |
| 111 | 152 Main procedure: |
| 153 - Exclusively create the foo.lock file using the O_CREAT and O_EXCL modes of | |
| 154 the system open() call. If the modify time of an existing lock file is | |
| 155 more than PATIENCE seconds old, then the lock file is deleted and the | |
| 156 exclusive create is retried. | |
| 157 - Load the extra field from the foo.gz file, and see if an operation was in | |
| 158 progress but not completed. If so, apply the recovery procedure below. | |
| 159 - Perform the append procedure with the provided data. | |
| 160 - If the uncompressed data in the foo.gz file is 1MB or more, apply the | |
| 161 compress procedure. | |
| 162 - Delete the foo.lock file. | |
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163 |
| 111 | 164 Append procedure: |
| 165 - Put what to append in the foo.add file so that the operation can be | |
| 166 restarted if this procedure is interrupted. | |
| 167 - Mark the foo.gz extra field with the append operation in progress. | |
| 168 + Restore the original last-block bit and stored block length of the last | |
| 169 stored block from the information in the extra field, in case a previous | |
| 170 append operation was interrupted. | |
| 171 - Append the provided data to the last stored block, creating new stored | |
| 172 blocks as needed and updating the stored blocks last-block bits and | |
| 173 lengths. | |
| 174 - Update the crc and length with the new data, and write the gzip trailer. | |
| 175 - Write over the extra field (with a single write operation) with the new | |
| 176 pointers, lengths, and crc's, and mark the gzip file as not in process. | |
| 177 Though there is still a foo.add file, it will be ignored since nothing | |
| 178 is in process. If a foo.add file is leftover from a previously | |
| 179 completed operation, it is truncated when writing new data to it. | |
| 180 - Delete the foo.add file. | |
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181 |
| 111 | 182 Compress and replace procedures: |
| 183 - Read all of the uncompressed data in the stored blocks in foo.gz and write | |
| 184 it to foo.add. Also write foo.temp with the last 32K of that data to | |
| 185 provide a dictionary for the next invocation of this procedure. | |
| 186 - Rewrite the extra field marking foo.gz with a compression in process. | |
| 187 * If there is no data provided to compress (due to a missing foo.add file | |
| 188 when recovering), reconstruct and truncate the foo.gz file to contain | |
| 189 only the previous compressed data and proceed to the step after the next | |
| 190 one. Otherwise ... | |
| 191 - Compress the data with the dictionary in foo.dict, and write to the | |
| 192 foo.gz file starting at the bit immediately following the last previously | |
| 193 compressed block. If there is no foo.dict, proceed anyway with the | |
| 194 compression at slightly reduced efficiency. (For the foo.dict file to be | |
| 195 missing requires some external failure beyond simply the interruption of | |
| 196 a compress operation.) During this process, the foo.lock file is | |
| 197 periodically touched to assure that that file is not considered stale by | |
| 198 another process before we're done. The deflation is terminated with a | |
| 199 non-last empty static block (10 bits long), that is then located and | |
| 200 written over by a last-bit-set empty stored block. | |
| 201 - Append the crc and length of the data in the gzip file (previously | |
| 202 calculated during the append operations). | |
| 203 - Write over the extra field with the updated stored block offsets, bits | |
| 204 back, crc's, and lengths, and mark foo.gz as in process for a replacement | |
| 205 of the dictionary. | |
| 206 @ Delete the foo.add file. | |
| 207 - Replace foo.dict with foo.temp. | |
| 208 - Write over the extra field, marking foo.gz as complete. | |
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209 |
| 111 | 210 Recovery procedure: |
| 211 - If not a replace recovery, read in the foo.add file, and provide that data | |
| 212 to the appropriate recovery below. If there is no foo.add file, provide | |
| 213 a zero data length to the recovery. In that case, the append recovery | |
| 214 restores the foo.gz to the previous compressed + uncompressed data state. | |
| 215 For the the compress recovery, a missing foo.add file results in foo.gz | |
| 216 being restored to the previous compressed-only data state. | |
| 217 - Append recovery: | |
| 218 - Pick up append at + step above | |
| 219 - Compress recovery: | |
| 220 - Pick up compress at * step above | |
| 221 - Replace recovery: | |
| 222 - Pick up compress at @ step above | |
| 223 - Log the repair with a date stamp in foo.repairs | |
| 224 */ | |
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225 |
| 111 | 226 #include <sys/types.h> |
| 227 #include <stdio.h> /* rename, fopen, fprintf, fclose */ | |
| 228 #include <stdlib.h> /* malloc, free */ | |
| 229 #include <string.h> /* strlen, strrchr, strcpy, strncpy, strcmp */ | |
| 230 #include <fcntl.h> /* open */ | |
| 231 #include <unistd.h> /* lseek, read, write, close, unlink, sleep, */ | |
| 232 /* ftruncate, fsync */ | |
| 233 #include <errno.h> /* errno */ | |
| 234 #include <time.h> /* time, ctime */ | |
| 235 #include <sys/stat.h> /* stat */ | |
| 236 #include <sys/time.h> /* utimes */ | |
| 237 #include "zlib.h" /* crc32 */ | |
| 238 | |
| 239 #include "gzlog.h" /* header for external access */ | |
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240 |
| 111 | 241 #define local static |
| 242 typedef unsigned int uint; | |
| 243 typedef unsigned long ulong; | |
| 244 | |
| 245 /* Macro for debugging to deterministically force recovery operations */ | |
| 246 #ifdef GZLOG_DEBUG | |
| 247 #include <setjmp.h> /* longjmp */ | |
| 248 jmp_buf gzlog_jump; /* where to go back to */ | |
| 249 int gzlog_bail = 0; /* which point to bail at (1..8) */ | |
| 250 int gzlog_count = -1; /* number of times through to wait */ | |
| 251 # define BAIL(n) do { if (n == gzlog_bail && gzlog_count-- == 0) \ | |
| 252 longjmp(gzlog_jump, gzlog_bail); } while (0) | |
| 253 #else | |
| 254 # define BAIL(n) | |
| 255 #endif | |
| 256 | |
| 257 /* how old the lock file can be in seconds before considering it stale */ | |
| 258 #define PATIENCE 300 | |
| 259 | |
| 260 /* maximum stored block size in Kbytes -- must be in 1..63 */ | |
| 261 #define MAX_STORE 16 | |
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262 |
| 111 | 263 /* number of stored Kbytes to trigger compression (must be >= 32 to allow |
| 264 dictionary construction, and <= 204 * MAX_STORE, in order for >> 10 to | |
| 265 discard the stored block headers contribution of five bytes each) */ | |
| 266 #define TRIGGER 1024 | |
| 267 | |
| 268 /* size of a deflate dictionary (this cannot be changed) */ | |
| 269 #define DICT 32768U | |
| 270 | |
| 271 /* values for the operation (2 bits) */ | |
| 272 #define NO_OP 0 | |
| 273 #define APPEND_OP 1 | |
| 274 #define COMPRESS_OP 2 | |
| 275 #define REPLACE_OP 3 | |
| 276 | |
| 277 /* macros to extract little-endian integers from an unsigned byte buffer */ | |
| 278 #define PULL2(p) ((p)[0]+((uint)((p)[1])<<8)) | |
| 279 #define PULL4(p) (PULL2(p)+((ulong)PULL2(p+2)<<16)) | |
| 280 #define PULL8(p) (PULL4(p)+((off_t)PULL4(p+4)<<32)) | |
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281 |
| 111 | 282 /* macros to store integers into a byte buffer in little-endian order */ |
| 283 #define PUT2(p,a) do {(p)[0]=a;(p)[1]=(a)>>8;} while(0) | |
| 284 #define PUT4(p,a) do {PUT2(p,a);PUT2(p+2,a>>16);} while(0) | |
| 285 #define PUT8(p,a) do {PUT4(p,a);PUT4(p+4,a>>32);} while(0) | |
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286 |
| 111 | 287 /* internal structure for log information */ |
| 288 #define LOGID "\106\035\172" /* should be three non-zero characters */ | |
| 289 struct log { | |
| 290 char id[4]; /* contains LOGID to detect inadvertent overwrites */ | |
| 291 int fd; /* file descriptor for .gz file, opened read/write */ | |
| 292 char *path; /* allocated path, e.g. "/var/log/foo" or "foo" */ | |
| 293 char *end; /* end of path, for appending suffices such as ".gz" */ | |
| 294 off_t first; /* offset of first stored block first length byte */ | |
| 295 int back; /* location of first block id in bits back from first */ | |
| 296 uint stored; /* bytes currently in last stored block */ | |
| 297 off_t last; /* offset of last stored block first length byte */ | |
| 298 ulong ccrc; /* crc of compressed data */ | |
| 299 ulong clen; /* length (modulo 2^32) of compressed data */ | |
| 300 ulong tcrc; /* crc of total data */ | |
| 301 ulong tlen; /* length (modulo 2^32) of total data */ | |
| 302 time_t lock; /* last modify time of our lock file */ | |
| 303 }; | |
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304 |
| 111 | 305 /* gzip header for gzlog */ |
| 306 local unsigned char log_gzhead[] = { | |
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307 0x1f, 0x8b, /* magic gzip id */ |
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308 8, /* compression method is deflate */ |
| 111 | 309 4, /* there is an extra field (no file name) */ |
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310 0, 0, 0, 0, /* no modification time provided */ |
| 111 | 311 0, 0xff, /* no extra flags, no OS specified */ |
| 312 39, 0, 'a', 'p', 35, 0 /* extra field with "ap" subfield */ | |
| 313 /* 35 is EXTRA, 39 is EXTRA + 4 */ | |
| 314 }; | |
| 315 | |
| 316 #define HEAD sizeof(log_gzhead) /* should be 16 */ | |
| 317 | |
| 318 /* initial gzip extra field content (52 == HEAD + EXTRA + 1) */ | |
| 319 local unsigned char log_gzext[] = { | |
| 320 52, 0, 0, 0, 0, 0, 0, 0, /* offset of first stored block length */ | |
| 321 52, 0, 0, 0, 0, 0, 0, 0, /* offset of last stored block length */ | |
| 322 0, 0, 0, 0, 0, 0, 0, 0, /* compressed data crc and length */ | |
| 323 0, 0, 0, 0, 0, 0, 0, 0, /* total data crc and length */ | |
| 324 0, 0, /* final stored block data length */ | |
| 325 5 /* op is NO_OP, last bit 8 bits back */ | |
| 326 }; | |
| 327 | |
| 328 #define EXTRA sizeof(log_gzext) /* should be 35 */ | |
| 329 | |
| 330 /* initial gzip data and trailer */ | |
| 331 local unsigned char log_gzbody[] = { | |
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332 1, 0, 0, 0xff, 0xff, /* empty stored block (last) */ |
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333 0, 0, 0, 0, /* crc */ |
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334 0, 0, 0, 0 /* uncompressed length */ |
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335 }; |
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336 |
| 111 | 337 #define BODY sizeof(log_gzbody) |
| 338 | |
| 339 /* Exclusively create foo.lock in order to negotiate exclusive access to the | |
| 340 foo.* files. If the modify time of an existing lock file is greater than | |
| 341 PATIENCE seconds in the past, then consider the lock file to have been | |
| 342 abandoned, delete it, and try the exclusive create again. Save the lock | |
| 343 file modify time for verification of ownership. Return 0 on success, or -1 | |
| 344 on failure, usually due to an access restriction or invalid path. Note that | |
| 345 if stat() or unlink() fails, it may be due to another process noticing the | |
| 346 abandoned lock file a smidge sooner and deleting it, so those are not | |
| 347 flagged as an error. */ | |
| 348 local int log_lock(struct log *log) | |
| 349 { | |
| 350 int fd; | |
| 351 struct stat st; | |
| 352 | |
| 353 strcpy(log->end, ".lock"); | |
| 354 while ((fd = open(log->path, O_CREAT | O_EXCL, 0644)) < 0) { | |
| 355 if (errno != EEXIST) | |
| 356 return -1; | |
| 357 if (stat(log->path, &st) == 0 && time(NULL) - st.st_mtime > PATIENCE) { | |
| 358 unlink(log->path); | |
| 359 continue; | |
| 360 } | |
| 361 sleep(2); /* relinquish the CPU for two seconds while waiting */ | |
| 362 } | |
| 363 close(fd); | |
| 364 if (stat(log->path, &st) == 0) | |
| 365 log->lock = st.st_mtime; | |
| 366 return 0; | |
| 367 } | |
| 368 | |
| 369 /* Update the modify time of the lock file to now, in order to prevent another | |
| 370 task from thinking that the lock is stale. Save the lock file modify time | |
| 371 for verification of ownership. */ | |
| 372 local void log_touch(struct log *log) | |
| 373 { | |
| 374 struct stat st; | |
| 375 | |
| 376 strcpy(log->end, ".lock"); | |
| 377 utimes(log->path, NULL); | |
| 378 if (stat(log->path, &st) == 0) | |
| 379 log->lock = st.st_mtime; | |
| 380 } | |
| 381 | |
| 382 /* Check the log file modify time against what is expected. Return true if | |
| 383 this is not our lock. If it is our lock, touch it to keep it. */ | |
| 384 local int log_check(struct log *log) | |
| 385 { | |
| 386 struct stat st; | |
| 387 | |
| 388 strcpy(log->end, ".lock"); | |
| 389 if (stat(log->path, &st) || st.st_mtime != log->lock) | |
| 390 return 1; | |
| 391 log_touch(log); | |
| 392 return 0; | |
| 393 } | |
| 394 | |
| 395 /* Unlock a previously acquired lock, but only if it's ours. */ | |
| 396 local void log_unlock(struct log *log) | |
| 397 { | |
| 398 if (log_check(log)) | |
| 399 return; | |
| 400 strcpy(log->end, ".lock"); | |
| 401 unlink(log->path); | |
| 402 log->lock = 0; | |
| 403 } | |
| 404 | |
| 405 /* Check the gzip header and read in the extra field, filling in the values in | |
| 406 the log structure. Return op on success or -1 if the gzip header was not as | |
| 407 expected. op is the current operation in progress last written to the extra | |
| 408 field. This assumes that the gzip file has already been opened, with the | |
| 409 file descriptor log->fd. */ | |
| 410 local int log_head(struct log *log) | |
| 411 { | |
| 412 int op; | |
| 413 unsigned char buf[HEAD + EXTRA]; | |
| 414 | |
| 415 if (lseek(log->fd, 0, SEEK_SET) < 0 || | |
| 416 read(log->fd, buf, HEAD + EXTRA) != HEAD + EXTRA || | |
| 417 memcmp(buf, log_gzhead, HEAD)) { | |
| 418 return -1; | |
| 419 } | |
| 420 log->first = PULL8(buf + HEAD); | |
| 421 log->last = PULL8(buf + HEAD + 8); | |
| 422 log->ccrc = PULL4(buf + HEAD + 16); | |
| 423 log->clen = PULL4(buf + HEAD + 20); | |
| 424 log->tcrc = PULL4(buf + HEAD + 24); | |
| 425 log->tlen = PULL4(buf + HEAD + 28); | |
| 426 log->stored = PULL2(buf + HEAD + 32); | |
| 427 log->back = 3 + (buf[HEAD + 34] & 7); | |
| 428 op = (buf[HEAD + 34] >> 3) & 3; | |
| 429 return op; | |
| 430 } | |
| 431 | |
| 432 /* Write over the extra field contents, marking the operation as op. Use fsync | |
| 433 to assure that the device is written to, and in the requested order. This | |
| 434 operation, and only this operation, is assumed to be atomic in order to | |
| 435 assure that the log is recoverable in the event of an interruption at any | |
| 436 point in the process. Return -1 if the write to foo.gz failed. */ | |
| 437 local int log_mark(struct log *log, int op) | |
| 438 { | |
| 439 int ret; | |
| 440 unsigned char ext[EXTRA]; | |
| 441 | |
| 442 PUT8(ext, log->first); | |
| 443 PUT8(ext + 8, log->last); | |
| 444 PUT4(ext + 16, log->ccrc); | |
| 445 PUT4(ext + 20, log->clen); | |
| 446 PUT4(ext + 24, log->tcrc); | |
| 447 PUT4(ext + 28, log->tlen); | |
| 448 PUT2(ext + 32, log->stored); | |
| 449 ext[34] = log->back - 3 + (op << 3); | |
| 450 fsync(log->fd); | |
| 451 ret = lseek(log->fd, HEAD, SEEK_SET) < 0 || | |
| 452 write(log->fd, ext, EXTRA) != EXTRA ? -1 : 0; | |
| 453 fsync(log->fd); | |
| 454 return ret; | |
| 455 } | |
| 456 | |
| 457 /* Rewrite the last block header bits and subsequent zero bits to get to a byte | |
| 458 boundary, setting the last block bit if last is true, and then write the | |
| 459 remainder of the stored block header (length and one's complement). Leave | |
| 460 the file pointer after the end of the last stored block data. Return -1 if | |
| 461 there is a read or write failure on the foo.gz file */ | |
| 462 local int log_last(struct log *log, int last) | |
| 463 { | |
| 464 int back, len, mask; | |
| 465 unsigned char buf[6]; | |
| 466 | |
| 467 /* determine the locations of the bytes and bits to modify */ | |
| 468 back = log->last == log->first ? log->back : 8; | |
| 469 len = back > 8 ? 2 : 1; /* bytes back from log->last */ | |
| 470 mask = 0x80 >> ((back - 1) & 7); /* mask for block last-bit */ | |
| 471 | |
| 472 /* get the byte to modify (one or two back) into buf[0] -- don't need to | |
| 473 read the byte if the last-bit is eight bits back, since in that case | |
| 474 the entire byte will be modified */ | |
| 475 buf[0] = 0; | |
| 476 if (back != 8 && (lseek(log->fd, log->last - len, SEEK_SET) < 0 || | |
| 477 read(log->fd, buf, 1) != 1)) | |
| 478 return -1; | |
| 479 | |
| 480 /* change the last-bit of the last stored block as requested -- note | |
| 481 that all bits above the last-bit are set to zero, per the type bits | |
| 482 of a stored block being 00 and per the convention that the bits to | |
| 483 bring the stream to a byte boundary are also zeros */ | |
| 484 buf[1] = 0; | |
| 485 buf[2 - len] = (*buf & (mask - 1)) + (last ? mask : 0); | |
| 486 | |
| 487 /* write the modified stored block header and lengths, move the file | |
| 488 pointer to after the last stored block data */ | |
| 489 PUT2(buf + 2, log->stored); | |
| 490 PUT2(buf + 4, log->stored ^ 0xffff); | |
| 491 return lseek(log->fd, log->last - len, SEEK_SET) < 0 || | |
| 492 write(log->fd, buf + 2 - len, len + 4) != len + 4 || | |
| 493 lseek(log->fd, log->stored, SEEK_CUR) < 0 ? -1 : 0; | |
| 494 } | |
| 495 | |
| 496 /* Append len bytes from data to the locked and open log file. len may be zero | |
| 497 if recovering and no .add file was found. In that case, the previous state | |
| 498 of the foo.gz file is restored. The data is appended uncompressed in | |
| 499 deflate stored blocks. Return -1 if there was an error reading or writing | |
| 500 the foo.gz file. */ | |
| 501 local int log_append(struct log *log, unsigned char *data, size_t len) | |
| 502 { | |
| 503 uint put; | |
| 504 off_t end; | |
| 505 unsigned char buf[8]; | |
| 506 | |
| 507 /* set the last block last-bit and length, in case recovering an | |
| 508 interrupted append, then position the file pointer to append to the | |
| 509 block */ | |
| 510 if (log_last(log, 1)) | |
| 511 return -1; | |
| 512 | |
| 513 /* append, adding stored blocks and updating the offset of the last stored | |
| 514 block as needed, and update the total crc and length */ | |
| 515 while (len) { | |
| 516 /* append as much as we can to the last block */ | |
| 517 put = (MAX_STORE << 10) - log->stored; | |
| 518 if (put > len) | |
| 519 put = (uint)len; | |
| 520 if (put) { | |
| 521 if (write(log->fd, data, put) != put) | |
| 522 return -1; | |
| 523 BAIL(1); | |
| 524 log->tcrc = crc32(log->tcrc, data, put); | |
| 525 log->tlen += put; | |
| 526 log->stored += put; | |
| 527 data += put; | |
| 528 len -= put; | |
| 529 } | |
| 530 | |
| 531 /* if we need to, add a new empty stored block */ | |
| 532 if (len) { | |
| 533 /* mark current block as not last */ | |
| 534 if (log_last(log, 0)) | |
| 535 return -1; | |
| 536 | |
| 537 /* point to new, empty stored block */ | |
| 538 log->last += 4 + log->stored + 1; | |
| 539 log->stored = 0; | |
| 540 } | |
| 541 | |
| 542 /* mark last block as last, update its length */ | |
| 543 if (log_last(log, 1)) | |
| 544 return -1; | |
| 545 BAIL(2); | |
| 546 } | |
| 547 | |
| 548 /* write the new crc and length trailer, and truncate just in case (could | |
| 549 be recovering from partial append with a missing foo.add file) */ | |
| 550 PUT4(buf, log->tcrc); | |
| 551 PUT4(buf + 4, log->tlen); | |
| 552 if (write(log->fd, buf, 8) != 8 || | |
| 553 (end = lseek(log->fd, 0, SEEK_CUR)) < 0 || ftruncate(log->fd, end)) | |
| 554 return -1; | |
| 555 | |
| 556 /* write the extra field, marking the log file as done, delete .add file */ | |
| 557 if (log_mark(log, NO_OP)) | |
| 558 return -1; | |
| 559 strcpy(log->end, ".add"); | |
| 560 unlink(log->path); /* ignore error, since may not exist */ | |
| 561 return 0; | |
| 562 } | |
| 563 | |
| 564 /* Replace the foo.dict file with the foo.temp file. Also delete the foo.add | |
| 565 file, since the compress operation may have been interrupted before that was | |
| 566 done. Returns 1 if memory could not be allocated, or -1 if reading or | |
| 567 writing foo.gz fails, or if the rename fails for some reason other than | |
| 568 foo.temp not existing. foo.temp not existing is a permitted error, since | |
| 569 the replace operation may have been interrupted after the rename is done, | |
| 570 but before foo.gz is marked as complete. */ | |
| 571 local int log_replace(struct log *log) | |
|
51
ae3a4bfb450b
add some files of version 4.4.3 that have been forgotten.
kent <kent@cr.ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
572 { |
| 111 | 573 int ret; |
| 574 char *dest; | |
| 575 | |
| 576 /* delete foo.add file */ | |
| 577 strcpy(log->end, ".add"); | |
| 578 unlink(log->path); /* ignore error, since may not exist */ | |
| 579 BAIL(3); | |
| 580 | |
| 581 /* rename foo.name to foo.dict, replacing foo.dict if it exists */ | |
| 582 strcpy(log->end, ".dict"); | |
| 583 dest = malloc(strlen(log->path) + 1); | |
| 584 if (dest == NULL) | |
| 585 return -2; | |
| 586 strcpy(dest, log->path); | |
| 587 strcpy(log->end, ".temp"); | |
| 588 ret = rename(log->path, dest); | |
| 589 free(dest); | |
| 590 if (ret && errno != ENOENT) | |
| 591 return -1; | |
| 592 BAIL(4); | |
| 593 | |
| 594 /* mark the foo.gz file as done */ | |
| 595 return log_mark(log, NO_OP); | |
| 596 } | |
| 597 | |
| 598 /* Compress the len bytes at data and append the compressed data to the | |
| 599 foo.gz deflate data immediately after the previous compressed data. This | |
| 600 overwrites the previous uncompressed data, which was stored in foo.add | |
| 601 and is the data provided in data[0..len-1]. If this operation is | |
| 602 interrupted, it picks up at the start of this routine, with the foo.add | |
| 603 file read in again. If there is no data to compress (len == 0), then we | |
| 604 simply terminate the foo.gz file after the previously compressed data, | |
| 605 appending a final empty stored block and the gzip trailer. Return -1 if | |
| 606 reading or writing the log.gz file failed, or -2 if there was a memory | |
| 607 allocation failure. */ | |
| 608 local int log_compress(struct log *log, unsigned char *data, size_t len) | |
| 609 { | |
| 610 int fd; | |
| 611 uint got, max; | |
| 612 ssize_t dict; | |
| 613 off_t end; | |
| 614 z_stream strm; | |
| 615 unsigned char buf[DICT]; | |
| 616 | |
| 617 /* compress and append compressed data */ | |
| 618 if (len) { | |
| 619 /* set up for deflate, allocating memory */ | |
| 620 strm.zalloc = Z_NULL; | |
| 621 strm.zfree = Z_NULL; | |
| 622 strm.opaque = Z_NULL; | |
| 623 if (deflateInit2(&strm, Z_DEFAULT_COMPRESSION, Z_DEFLATED, -15, 8, | |
| 624 Z_DEFAULT_STRATEGY) != Z_OK) | |
| 625 return -2; | |
| 626 | |
| 627 /* read in dictionary (last 32K of data that was compressed) */ | |
| 628 strcpy(log->end, ".dict"); | |
| 629 fd = open(log->path, O_RDONLY, 0); | |
| 630 if (fd >= 0) { | |
| 631 dict = read(fd, buf, DICT); | |
| 632 close(fd); | |
| 633 if (dict < 0) { | |
| 634 deflateEnd(&strm); | |
| 635 return -1; | |
| 636 } | |
| 637 if (dict) | |
| 638 deflateSetDictionary(&strm, buf, (uint)dict); | |
| 639 } | |
| 640 log_touch(log); | |
| 641 | |
| 642 /* prime deflate with last bits of previous block, position write | |
| 643 pointer to write those bits and overwrite what follows */ | |
| 644 if (lseek(log->fd, log->first - (log->back > 8 ? 2 : 1), | |
| 645 SEEK_SET) < 0 || | |
| 646 read(log->fd, buf, 1) != 1 || lseek(log->fd, -1, SEEK_CUR) < 0) { | |
| 647 deflateEnd(&strm); | |
| 648 return -1; | |
| 649 } | |
| 650 deflatePrime(&strm, (8 - log->back) & 7, *buf); | |
| 651 | |
| 652 /* compress, finishing with a partial non-last empty static block */ | |
| 653 strm.next_in = data; | |
| 654 max = (((uint)0 - 1) >> 1) + 1; /* in case int smaller than size_t */ | |
| 655 do { | |
| 656 strm.avail_in = len > max ? max : (uint)len; | |
| 657 len -= strm.avail_in; | |
| 658 do { | |
| 659 strm.avail_out = DICT; | |
| 660 strm.next_out = buf; | |
| 661 deflate(&strm, len ? Z_NO_FLUSH : Z_PARTIAL_FLUSH); | |
| 662 got = DICT - strm.avail_out; | |
| 663 if (got && write(log->fd, buf, got) != got) { | |
| 664 deflateEnd(&strm); | |
| 665 return -1; | |
| 666 } | |
| 667 log_touch(log); | |
| 668 } while (strm.avail_out == 0); | |
| 669 } while (len); | |
| 670 deflateEnd(&strm); | |
| 671 BAIL(5); | |
| 672 | |
| 673 /* find start of empty static block -- scanning backwards the first one | |
| 674 bit is the second bit of the block, if the last byte is zero, then | |
| 675 we know the byte before that has a one in the top bit, since an | |
| 676 empty static block is ten bits long */ | |
| 677 if ((log->first = lseek(log->fd, -1, SEEK_CUR)) < 0 || | |
| 678 read(log->fd, buf, 1) != 1) | |
| 679 return -1; | |
| 680 log->first++; | |
| 681 if (*buf) { | |
| 682 log->back = 1; | |
| 683 while ((*buf & ((uint)1 << (8 - log->back++))) == 0) | |
| 684 ; /* guaranteed to terminate, since *buf != 0 */ | |
| 685 } | |
| 686 else | |
| 687 log->back = 10; | |
| 688 | |
| 689 /* update compressed crc and length */ | |
| 690 log->ccrc = log->tcrc; | |
| 691 log->clen = log->tlen; | |
| 692 } | |
| 693 else { | |
| 694 /* no data to compress -- fix up existing gzip stream */ | |
| 695 log->tcrc = log->ccrc; | |
| 696 log->tlen = log->clen; | |
| 697 } | |
| 698 | |
| 699 /* complete and truncate gzip stream */ | |
| 700 log->last = log->first; | |
| 701 log->stored = 0; | |
| 702 PUT4(buf, log->tcrc); | |
| 703 PUT4(buf + 4, log->tlen); | |
| 704 if (log_last(log, 1) || write(log->fd, buf, 8) != 8 || | |
| 705 (end = lseek(log->fd, 0, SEEK_CUR)) < 0 || ftruncate(log->fd, end)) | |
| 706 return -1; | |
| 707 BAIL(6); | |
| 708 | |
| 709 /* mark as being in the replace operation */ | |
| 710 if (log_mark(log, REPLACE_OP)) | |
| 711 return -1; | |
| 712 | |
| 713 /* execute the replace operation and mark the file as done */ | |
| 714 return log_replace(log); | |
| 715 } | |
| 716 | |
| 717 /* log a repair record to the .repairs file */ | |
| 718 local void log_log(struct log *log, int op, char *record) | |
| 719 { | |
| 720 time_t now; | |
| 721 FILE *rec; | |
|
51
ae3a4bfb450b
add some files of version 4.4.3 that have been forgotten.
kent <kent@cr.ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
722 |
| 111 | 723 now = time(NULL); |
| 724 strcpy(log->end, ".repairs"); | |
| 725 rec = fopen(log->path, "a"); | |
| 726 if (rec == NULL) | |
| 727 return; | |
| 728 fprintf(rec, "%.24s %s recovery: %s\n", ctime(&now), op == APPEND_OP ? | |
| 729 "append" : (op == COMPRESS_OP ? "compress" : "replace"), record); | |
| 730 fclose(rec); | |
| 731 return; | |
| 732 } | |
| 733 | |
| 734 /* Recover the interrupted operation op. First read foo.add for recovering an | |
| 735 append or compress operation. Return -1 if there was an error reading or | |
| 736 writing foo.gz or reading an existing foo.add, or -2 if there was a memory | |
| 737 allocation failure. */ | |
| 738 local int log_recover(struct log *log, int op) | |
| 739 { | |
| 740 int fd, ret = 0; | |
| 741 unsigned char *data = NULL; | |
| 742 size_t len = 0; | |
| 743 struct stat st; | |
| 744 | |
| 745 /* log recovery */ | |
| 746 log_log(log, op, "start"); | |
| 747 | |
| 748 /* load foo.add file if expected and present */ | |
| 749 if (op == APPEND_OP || op == COMPRESS_OP) { | |
| 750 strcpy(log->end, ".add"); | |
| 751 if (stat(log->path, &st) == 0 && st.st_size) { | |
| 752 len = (size_t)(st.st_size); | |
| 753 if ((off_t)len != st.st_size || | |
| 754 (data = malloc(st.st_size)) == NULL) { | |
| 755 log_log(log, op, "allocation failure"); | |
| 756 return -2; | |
| 757 } | |
| 758 if ((fd = open(log->path, O_RDONLY, 0)) < 0) { | |
| 759 log_log(log, op, ".add file read failure"); | |
| 760 return -1; | |
| 761 } | |
| 762 ret = (size_t)read(fd, data, len) != len; | |
| 763 close(fd); | |
| 764 if (ret) { | |
| 765 log_log(log, op, ".add file read failure"); | |
| 766 return -1; | |
| 767 } | |
| 768 log_log(log, op, "loaded .add file"); | |
| 769 } | |
| 770 else | |
| 771 log_log(log, op, "missing .add file!"); | |
| 772 } | |
| 773 | |
| 774 /* recover the interrupted operation */ | |
| 775 switch (op) { | |
| 776 case APPEND_OP: | |
| 777 ret = log_append(log, data, len); | |
| 778 break; | |
| 779 case COMPRESS_OP: | |
| 780 ret = log_compress(log, data, len); | |
| 781 break; | |
| 782 case REPLACE_OP: | |
| 783 ret = log_replace(log); | |
| 784 } | |
| 785 | |
| 786 /* log status */ | |
| 787 log_log(log, op, ret ? "failure" : "complete"); | |
| 788 | |
| 789 /* clean up */ | |
| 790 if (data != NULL) | |
| 791 free(data); | |
| 792 return ret; | |
| 793 } | |
| 794 | |
| 795 /* Close the foo.gz file (if open) and release the lock. */ | |
| 796 local void log_close(struct log *log) | |
| 797 { | |
| 798 if (log->fd >= 0) | |
| 799 close(log->fd); | |
| 800 log->fd = -1; | |
| 801 log_unlock(log); | |
| 802 } | |
| 803 | |
| 804 /* Open foo.gz, verify the header, and load the extra field contents, after | |
| 805 first creating the foo.lock file to gain exclusive access to the foo.* | |
| 806 files. If foo.gz does not exist or is empty, then write the initial header, | |
| 807 extra, and body content of an empty foo.gz log file. If there is an error | |
| 808 creating the lock file due to access restrictions, or an error reading or | |
| 809 writing the foo.gz file, or if the foo.gz file is not a proper log file for | |
| 810 this object (e.g. not a gzip file or does not contain the expected extra | |
| 811 field), then return true. If there is an error, the lock is released. | |
| 812 Otherwise, the lock is left in place. */ | |
| 813 local int log_open(struct log *log) | |
| 814 { | |
| 815 int op; | |
| 816 | |
| 817 /* release open file resource if left over -- can occur if lock lost | |
| 818 between gzlog_open() and gzlog_write() */ | |
| 819 if (log->fd >= 0) | |
| 820 close(log->fd); | |
| 821 log->fd = -1; | |
| 822 | |
| 823 /* negotiate exclusive access */ | |
| 824 if (log_lock(log) < 0) | |
| 825 return -1; | |
| 826 | |
| 827 /* open the log file, foo.gz */ | |
| 828 strcpy(log->end, ".gz"); | |
| 829 log->fd = open(log->path, O_RDWR | O_CREAT, 0644); | |
| 830 if (log->fd < 0) { | |
| 831 log_close(log); | |
| 832 return -1; | |
| 833 } | |
| 834 | |
| 835 /* if new, initialize foo.gz with an empty log, delete old dictionary */ | |
| 836 if (lseek(log->fd, 0, SEEK_END) == 0) { | |
| 837 if (write(log->fd, log_gzhead, HEAD) != HEAD || | |
| 838 write(log->fd, log_gzext, EXTRA) != EXTRA || | |
| 839 write(log->fd, log_gzbody, BODY) != BODY) { | |
| 840 log_close(log); | |
| 841 return -1; | |
| 842 } | |
| 843 strcpy(log->end, ".dict"); | |
| 844 unlink(log->path); | |
| 845 } | |
| 846 | |
| 847 /* verify log file and load extra field information */ | |
| 848 if ((op = log_head(log)) < 0) { | |
| 849 log_close(log); | |
| 850 return -1; | |
| 851 } | |
| 852 | |
| 853 /* check for interrupted process and if so, recover */ | |
| 854 if (op != NO_OP && log_recover(log, op)) { | |
| 855 log_close(log); | |
| 856 return -1; | |
| 857 } | |
| 858 | |
| 859 /* touch the lock file to prevent another process from grabbing it */ | |
| 860 log_touch(log); | |
| 861 return 0; | |
| 862 } | |
| 863 | |
| 864 /* See gzlog.h for the description of the external methods below */ | |
| 865 gzlog *gzlog_open(char *path) | |
| 866 { | |
| 867 size_t n; | |
| 868 struct log *log; | |
| 869 | |
| 870 /* check arguments */ | |
| 871 if (path == NULL || *path == 0) | |
| 872 return NULL; | |
| 873 | |
| 874 /* allocate and initialize log structure */ | |
| 875 log = malloc(sizeof(struct log)); | |
|
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876 if (log == NULL) |
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877 return NULL; |
| 111 | 878 strcpy(log->id, LOGID); |
| 879 log->fd = -1; | |
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880 |
| 111 | 881 /* save path and end of path for name construction */ |
| 882 n = strlen(path); | |
| 883 log->path = malloc(n + 9); /* allow for ".repairs" */ | |
| 884 if (log->path == NULL) { | |
|
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885 free(log); |
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886 return NULL; |
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887 } |
| 111 | 888 strcpy(log->path, path); |
| 889 log->end = log->path + n; | |
| 890 | |
| 891 /* gain exclusive access and verify log file -- may perform a | |
| 892 recovery operation if needed */ | |
| 893 if (log_open(log)) { | |
| 894 free(log->path); | |
|
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895 free(log); |
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896 return NULL; |
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897 } |
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898 |
| 111 | 899 /* return pointer to log structure */ |
| 900 return log; | |
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901 } |
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902 |
| 111 | 903 /* gzlog_compress() return values: |
| 904 0: all good | |
| 905 -1: file i/o error (usually access issue) | |
| 906 -2: memory allocation failure | |
| 907 -3: invalid log pointer argument */ | |
| 908 int gzlog_compress(gzlog *logd) | |
|
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909 { |
| 111 | 910 int fd, ret; |
| 911 uint block; | |
| 912 size_t len, next; | |
| 913 unsigned char *data, buf[5]; | |
| 914 struct log *log = logd; | |
| 915 | |
| 916 /* check arguments */ | |
| 917 if (log == NULL || strcmp(log->id, LOGID)) | |
| 918 return -3; | |
| 919 | |
| 920 /* see if we lost the lock -- if so get it again and reload the extra | |
| 921 field information (it probably changed), recover last operation if | |
| 922 necessary */ | |
| 923 if (log_check(log) && log_open(log)) | |
| 924 return -1; | |
| 925 | |
| 926 /* create space for uncompressed data */ | |
| 927 len = ((size_t)(log->last - log->first) & ~(((size_t)1 << 10) - 1)) + | |
| 928 log->stored; | |
| 929 if ((data = malloc(len)) == NULL) | |
| 930 return -2; | |
|
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931 |
| 111 | 932 /* do statement here is just a cheap trick for error handling */ |
| 933 do { | |
| 934 /* read in the uncompressed data */ | |
| 935 if (lseek(log->fd, log->first - 1, SEEK_SET) < 0) | |
| 936 break; | |
| 937 next = 0; | |
| 938 while (next < len) { | |
| 939 if (read(log->fd, buf, 5) != 5) | |
| 940 break; | |
| 941 block = PULL2(buf + 1); | |
| 942 if (next + block > len || | |
| 943 read(log->fd, (char *)data + next, block) != block) | |
| 944 break; | |
| 945 next += block; | |
| 946 } | |
| 947 if (lseek(log->fd, 0, SEEK_CUR) != log->last + 4 + log->stored) | |
| 948 break; | |
| 949 log_touch(log); | |
|
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950 |
| 111 | 951 /* write the uncompressed data to the .add file */ |
| 952 strcpy(log->end, ".add"); | |
| 953 fd = open(log->path, O_WRONLY | O_CREAT | O_TRUNC, 0644); | |
| 954 if (fd < 0) | |
| 955 break; | |
| 956 ret = (size_t)write(fd, data, len) != len; | |
| 957 if (ret | close(fd)) | |
| 958 break; | |
| 959 log_touch(log); | |
| 960 | |
| 961 /* write the dictionary for the next compress to the .temp file */ | |
| 962 strcpy(log->end, ".temp"); | |
| 963 fd = open(log->path, O_WRONLY | O_CREAT | O_TRUNC, 0644); | |
| 964 if (fd < 0) | |
| 965 break; | |
| 966 next = DICT > len ? len : DICT; | |
| 967 ret = (size_t)write(fd, (char *)data + len - next, next) != next; | |
| 968 if (ret | close(fd)) | |
| 969 break; | |
| 970 log_touch(log); | |
| 971 | |
| 972 /* roll back to compressed data, mark the compress in progress */ | |
| 973 log->last = log->first; | |
| 974 log->stored = 0; | |
| 975 if (log_mark(log, COMPRESS_OP)) | |
|
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976 break; |
| 111 | 977 BAIL(7); |
| 978 | |
| 979 /* compress and append the data (clears mark) */ | |
| 980 ret = log_compress(log, data, len); | |
| 981 free(data); | |
| 982 return ret; | |
| 983 } while (0); | |
| 984 | |
| 985 /* broke out of do above on i/o error */ | |
| 986 free(data); | |
| 987 return -1; | |
| 988 } | |
| 989 | |
| 990 /* gzlog_write() return values: | |
| 991 0: all good | |
| 992 -1: file i/o error (usually access issue) | |
| 993 -2: memory allocation failure | |
| 994 -3: invalid log pointer argument */ | |
| 995 int gzlog_write(gzlog *logd, void *data, size_t len) | |
| 996 { | |
| 997 int fd, ret; | |
| 998 struct log *log = logd; | |
| 999 | |
| 1000 /* check arguments */ | |
| 1001 if (log == NULL || strcmp(log->id, LOGID)) | |
| 1002 return -3; | |
| 1003 if (data == NULL || len <= 0) | |
| 1004 return 0; | |
| 1005 | |
| 1006 /* see if we lost the lock -- if so get it again and reload the extra | |
| 1007 field information (it probably changed), recover last operation if | |
| 1008 necessary */ | |
| 1009 if (log_check(log) && log_open(log)) | |
| 1010 return -1; | |
|
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1011 |
| 111 | 1012 /* create and write .add file */ |
| 1013 strcpy(log->end, ".add"); | |
| 1014 fd = open(log->path, O_WRONLY | O_CREAT | O_TRUNC, 0644); | |
| 1015 if (fd < 0) | |
| 1016 return -1; | |
| 1017 ret = (size_t)write(fd, data, len) != len; | |
| 1018 if (ret | close(fd)) | |
| 1019 return -1; | |
| 1020 log_touch(log); | |
| 1021 | |
| 1022 /* mark log file with append in progress */ | |
| 1023 if (log_mark(log, APPEND_OP)) | |
| 1024 return -1; | |
| 1025 BAIL(8); | |
| 1026 | |
| 1027 /* append data (clears mark) */ | |
| 1028 if (log_append(log, data, len)) | |
| 1029 return -1; | |
| 1030 | |
| 1031 /* check to see if it's time to compress -- if not, then done */ | |
| 1032 if (((log->last - log->first) >> 10) + (log->stored >> 10) < TRIGGER) | |
| 1033 return 0; | |
|
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1034 |
| 111 | 1035 /* time to compress */ |
| 1036 return gzlog_compress(log); | |
| 1037 } | |
| 1038 | |
| 1039 /* gzlog_close() return values: | |
| 1040 0: ok | |
| 1041 -3: invalid log pointer argument */ | |
| 1042 int gzlog_close(gzlog *logd) | |
| 1043 { | |
| 1044 struct log *log = logd; | |
|
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1045 |
| 111 | 1046 /* check arguments */ |
| 1047 if (log == NULL || strcmp(log->id, LOGID)) | |
| 1048 return -3; | |
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1049 |
| 111 | 1050 /* close the log file and release the lock */ |
| 1051 log_close(log); | |
| 1052 | |
| 1053 /* free structure and return */ | |
| 1054 if (log->path != NULL) | |
| 1055 free(log->path); | |
| 1056 strcpy(log->id, "bad"); | |
| 1057 free(log); | |
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1058 return 0; |
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1059 } |