GCC Code Coverage Report
Directory: ./ Exec Total Coverage
File: usr.sbin/syslogd/ringbuf.c Lines: 0 50 0.0 %
Date: 2017-11-13 Branches: 0 32 0.0 %

Line Branch Exec Source
1
/* $OpenBSD: ringbuf.c,v 1.10 2016/10/16 22:12:50 bluhm Exp $ */
2
3
/*
4
 * Copyright (c) 2004 Damien Miller
5
 *
6
 * Permission to use, copy, modify, and distribute this software for any
7
 * purpose with or without fee is hereby granted, provided that the above
8
 * copyright notice and this permission notice appear in all copies.
9
 *
10
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
11
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
12
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
13
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
14
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
15
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
16
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
17
 */
18
19
/*
20
 * Simple ringbuffer for lines of text.
21
 */
22
23
#include <stdio.h>
24
#include <stdlib.h>
25
#include <string.h>
26
27
#include "syslogd.h"
28
29
#define MINIMUM(a, b)	(((a) < (b)) ? (a) : (b))
30
31
/* Initialise a ring buffer */
32
struct ringbuf *
33
ringbuf_init(size_t len)
34
{
35
	struct ringbuf *ret;
36
37
	if (len == 0 || (ret = malloc(sizeof(*ret))) == NULL)
38
		return (NULL);
39
40
	if ((ret->buf = malloc(len)) == NULL) {
41
		free(ret);
42
		return (NULL);
43
	}
44
45
	ret->len = len;
46
	ret->start = ret->end = 0;
47
48
	return (ret);
49
}
50
51
/* Free a ring buffer */
52
void
53
ringbuf_free(struct ringbuf *rb)
54
{
55
	free(rb->buf);
56
	free(rb);
57
}
58
59
/* Clear a ring buffer */
60
void
61
ringbuf_clear(struct ringbuf *rb)
62
{
63
	rb->start = rb->end = 0;
64
}
65
66
/* Return the number of bytes used in a ringbuffer */
67
size_t
68
ringbuf_used(struct ringbuf *rb)
69
{
70
	return ((rb->len + rb->end - rb->start) % rb->len);
71
}
72
73
/*
74
 * Append a line to a ring buffer, will delete lines from start
75
 * of buffer as necessary
76
 */
77
int
78
ringbuf_append_line(struct ringbuf *rb, char *line)
79
{
80
	size_t llen, used, copy_len;
81
	int overflow = 0;
82
83
	if (rb == NULL || line == NULL)
84
		return (-1);
85
86
	llen = strlen(line);
87
	if (llen == 0)
88
		return (-1);
89
90
	if (line[llen - 1] != '\n')
91
		llen++; /* one extra for appended '\n' */
92
93
	if (llen >= rb->len)
94
		return (-1);
95
96
	/*
97
	 * If necessary, advance start pointer to make room for appended
98
	 * string. Ensure that start pointer is at the beginning of a line
99
	 * once we are done (i.e move to after '\n').
100
	 */
101
	used = ringbuf_used(rb);
102
	if (used + llen >= rb->len) {
103
		rb->start = (rb->start + used + llen - rb->len) % rb->len;
104
105
		/* Find next '\n' */
106
		while (rb->buf[rb->start] != '\n')
107
			rb->start = (rb->start + 1) % rb->len;
108
		/* Skip it */
109
		rb->start = (rb->start + 1) % rb->len;
110
111
		overflow = 1;
112
	}
113
114
	/*
115
	 * Now append string, starting from last pointer and wrapping if
116
	 * necessary
117
	 */
118
	if (rb->end + llen > rb->len) {
119
		copy_len = rb->len - rb->end;
120
		memcpy(rb->buf + rb->end, line, copy_len);
121
		memcpy(rb->buf, line + copy_len, llen - copy_len - 1);
122
		rb->buf[llen - copy_len - 1] = '\n';
123
	} else {
124
		memcpy(rb->buf + rb->end, line, llen - 1);
125
		rb->buf[rb->end + llen - 1] = '\n';
126
	}
127
128
	rb->end = (rb->end + llen) % rb->len;
129
130
	return (overflow);
131
}
132
133
/*
134
 * Copy and nul-terminate a ringbuffer to a string.
135
 */
136
ssize_t
137
ringbuf_to_string(char *buf, size_t len, struct ringbuf *rb)
138
{
139
	size_t copy_len, n;
140
141
	if (buf == NULL || rb == NULL || len == 0)
142
		return (-1);
143
144
	copy_len = MINIMUM(len - 1, ringbuf_used(rb));
145
146
	if (copy_len == 0)
147
		return (copy_len);
148
149
	if (rb->start < rb->end)
150
		memcpy(buf, rb->buf + rb->start, copy_len);
151
	else {
152
		/* If the buffer is wrapped, copy each hunk separately */
153
		n = rb->len - rb->start;
154
		memcpy(buf, rb->buf + rb->start, MINIMUM(n, copy_len));
155
		if (copy_len > n)
156
			memcpy(buf + n, rb->buf,
157
			    MINIMUM(rb->end, copy_len - n));
158
	}
159
	buf[copy_len] = '\0';
160
161
	return (ringbuf_used(rb));
162
}