1 /* $Id: dba_write.c,v 1.3 2016/08/05 23:15:08 schwarze Exp $ */
2 /*
3 * Copyright (c) 2016 Ingo Schwarze <schwarze@openbsd.org>
4 *
5 * Permission to use, copy, modify, and distribute this software for any
6 * purpose with or without fee is hereby granted, provided that the above
7 * copyright notice and this permission notice appear in all copies.
8 *
9 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
12 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
15 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16 *
17 * Low-level functions for serializing allocation-based data to disk.
18 * The interface is defined in "dba_write.h".
19 */
20 #include "config.h"
21
22 #include <assert.h>
23 #if HAVE_ENDIAN
24 #include <endian.h>
25 #elif HAVE_SYS_ENDIAN
26 #include <sys/endian.h>
27 #elif HAVE_NTOHL
28 #include <arpa/inet.h>
29 #endif
30 #if HAVE_ERR
31 #include <err.h>
32 #endif
33 #include <errno.h>
34 #include <fcntl.h>
35 #include <stdint.h>
36 #include <stdio.h>
37
38 #include "dba_write.h"
39
40 static FILE *ofp;
41
42
43 int
dba_open(const char * fname)44 dba_open(const char *fname)
45 {
46 ofp = fopen(fname, "w");
47 return ofp == NULL ? -1 : 0;
48 }
49
50 int
dba_close(void)51 dba_close(void)
52 {
53 return fclose(ofp) == EOF ? -1 : 0;
54 }
55
56 int32_t
dba_tell(void)57 dba_tell(void)
58 {
59 long pos;
60
61 if ((pos = ftell(ofp)) == -1)
62 err(1, "ftell");
63 if (pos >= INT32_MAX) {
64 errno = EOVERFLOW;
65 err(1, "ftell = %ld", pos);
66 }
67 return pos;
68 }
69
70 void
dba_seek(int32_t pos)71 dba_seek(int32_t pos)
72 {
73 if (fseek(ofp, pos, SEEK_SET) == -1)
74 err(1, "fseek(%d)", pos);
75 }
76
77 int32_t
dba_align(void)78 dba_align(void)
79 {
80 int32_t pos;
81
82 pos = dba_tell();
83 while (pos & 3) {
84 dba_char_write('\0');
85 pos++;
86 }
87 return pos;
88 }
89
90 int32_t
dba_skip(int32_t nmemb,int32_t sz)91 dba_skip(int32_t nmemb, int32_t sz)
92 {
93 const int32_t out[5] = {0, 0, 0, 0, 0};
94 int32_t i, pos;
95
96 assert(sz >= 0);
97 assert(nmemb > 0);
98 assert(nmemb <= 5);
99 pos = dba_tell();
100 for (i = 0; i < sz; i++)
101 if (nmemb - fwrite(&out, sizeof(out[0]), nmemb, ofp))
102 err(1, "fwrite");
103 return pos;
104 }
105
106 void
dba_char_write(int c)107 dba_char_write(int c)
108 {
109 if (putc(c, ofp) == EOF)
110 err(1, "fputc");
111 }
112
113 void
dba_str_write(const char * str)114 dba_str_write(const char *str)
115 {
116 if (fputs(str, ofp) == EOF)
117 err(1, "fputs");
118 dba_char_write('\0');
119 }
120
121 void
dba_int_write(int32_t i)122 dba_int_write(int32_t i)
123 {
124 i = htobe32(i);
125 if (fwrite(&i, sizeof(i), 1, ofp) != 1)
126 err(1, "fwrite");
127 }
128