1 /* $OpenBSD: dba_write.c,v 1.1 2016/08/01 10:32:39 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 <assert.h>
21 #include <endian.h>
22 #include <err.h>
23 #include <errno.h>
24 #include <fcntl.h>
25 #include <stdint.h>
26 #include <stdio.h>
27
28 #include "dba_write.h"
29
30 static FILE *ofp;
31
32
33 int
dba_open(const char * fname)34 dba_open(const char *fname)
35 {
36 ofp = fopen(fname, "w");
37 return ofp == NULL ? -1 : 0;
38 }
39
40 int
dba_close(void)41 dba_close(void)
42 {
43 return fclose(ofp) == EOF ? -1 : 0;
44 }
45
46 int32_t
dba_tell(void)47 dba_tell(void)
48 {
49 long pos;
50
51 if ((pos = ftell(ofp)) == -1)
52 err(1, "ftell");
53 if (pos >= INT32_MAX) {
54 errno = EOVERFLOW;
55 err(1, "ftell = %ld", pos);
56 }
57 return pos;
58 }
59
60 void
dba_seek(int32_t pos)61 dba_seek(int32_t pos)
62 {
63 if (fseek(ofp, pos, SEEK_SET) == -1)
64 err(1, "fseek(%d)", pos);
65 }
66
67 int32_t
dba_align(void)68 dba_align(void)
69 {
70 int32_t pos;
71
72 pos = dba_tell();
73 while (pos & 3) {
74 dba_char_write('\0');
75 pos++;
76 }
77 return pos;
78 }
79
80 int32_t
dba_skip(int32_t nmemb,int32_t sz)81 dba_skip(int32_t nmemb, int32_t sz)
82 {
83 const int32_t out[5] = {0, 0, 0, 0, 0};
84 int32_t i, pos;
85
86 assert(sz >= 0);
87 assert(nmemb > 0);
88 assert(nmemb <= 5);
89 pos = dba_tell();
90 for (i = 0; i < sz; i++)
91 if (nmemb - fwrite(&out, sizeof(out[0]), nmemb, ofp))
92 err(1, "fwrite");
93 return pos;
94 }
95
96 void
dba_char_write(int c)97 dba_char_write(int c)
98 {
99 if (putc(c, ofp) == EOF)
100 err(1, "fputc");
101 }
102
103 void
dba_str_write(const char * str)104 dba_str_write(const char *str)
105 {
106 if (fputs(str, ofp) == EOF)
107 err(1, "fputs");
108 dba_char_write('\0');
109 }
110
111 void
dba_int_write(int32_t i)112 dba_int_write(int32_t i)
113 {
114 i = htobe32(i);
115 if (fwrite(&i, sizeof(i), 1, ofp) != 1)
116 err(1, "fwrite");
117 }
118