Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
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linux
1/*
2 * Copyright (C) 2009 Red Hat Inc, Steven Rostedt <srostedt@redhat.com>
3 *
4 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
5 * This program is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU Lesser General Public
7 * License as published by the Free Software Foundation;
8 * version 2.1 of the License (not later!)
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU Lesser General Public License for more details.
14 *
15 * You should have received a copy of the GNU Lesser General Public
16 * License along with this program; if not, see <http://www.gnu.org/licenses>
17 *
18 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
19 */
20#include <stdio.h>
21#include <stdlib.h>
22#include <string.h>
23#include <stdarg.h>
24
25#include "event-parse.h"
26#include "event-utils.h"
27
28/*
29 * The TRACE_SEQ_POISON is to catch the use of using
30 * a trace_seq structure after it was destroyed.
31 */
32#define TRACE_SEQ_POISON ((void *)0xdeadbeef)
33#define TRACE_SEQ_CHECK(s) \
34do { \
35 if ((s)->buffer == TRACE_SEQ_POISON) \
36 die("Usage of trace_seq after it was destroyed"); \
37} while (0)
38
39/**
40 * trace_seq_init - initialize the trace_seq structure
41 * @s: a pointer to the trace_seq structure to initialize
42 */
43void trace_seq_init(struct trace_seq *s)
44{
45 s->len = 0;
46 s->readpos = 0;
47 s->buffer_size = TRACE_SEQ_BUF_SIZE;
48 s->buffer = malloc_or_die(s->buffer_size);
49}
50
51/**
52 * trace_seq_destroy - free up memory of a trace_seq
53 * @s: a pointer to the trace_seq to free the buffer
54 *
55 * Only frees the buffer, not the trace_seq struct itself.
56 */
57void trace_seq_destroy(struct trace_seq *s)
58{
59 if (!s)
60 return;
61 TRACE_SEQ_CHECK(s);
62 free(s->buffer);
63 s->buffer = TRACE_SEQ_POISON;
64}
65
66static void expand_buffer(struct trace_seq *s)
67{
68 s->buffer_size += TRACE_SEQ_BUF_SIZE;
69 s->buffer = realloc(s->buffer, s->buffer_size);
70 if (!s->buffer)
71 die("Can't allocate trace_seq buffer memory");
72}
73
74/**
75 * trace_seq_printf - sequence printing of trace information
76 * @s: trace sequence descriptor
77 * @fmt: printf format string
78 *
79 * It returns 0 if the trace oversizes the buffer's free
80 * space, 1 otherwise.
81 *
82 * The tracer may use either sequence operations or its own
83 * copy to user routines. To simplify formating of a trace
84 * trace_seq_printf is used to store strings into a special
85 * buffer (@s). Then the output may be either used by
86 * the sequencer or pulled into another buffer.
87 */
88int
89trace_seq_printf(struct trace_seq *s, const char *fmt, ...)
90{
91 va_list ap;
92 int len;
93 int ret;
94
95 TRACE_SEQ_CHECK(s);
96
97 try_again:
98 len = (s->buffer_size - 1) - s->len;
99
100 va_start(ap, fmt);
101 ret = vsnprintf(s->buffer + s->len, len, fmt, ap);
102 va_end(ap);
103
104 if (ret >= len) {
105 expand_buffer(s);
106 goto try_again;
107 }
108
109 s->len += ret;
110
111 return 1;
112}
113
114/**
115 * trace_seq_vprintf - sequence printing of trace information
116 * @s: trace sequence descriptor
117 * @fmt: printf format string
118 *
119 * The tracer may use either sequence operations or its own
120 * copy to user routines. To simplify formating of a trace
121 * trace_seq_printf is used to store strings into a special
122 * buffer (@s). Then the output may be either used by
123 * the sequencer or pulled into another buffer.
124 */
125int
126trace_seq_vprintf(struct trace_seq *s, const char *fmt, va_list args)
127{
128 int len;
129 int ret;
130
131 TRACE_SEQ_CHECK(s);
132
133 try_again:
134 len = (s->buffer_size - 1) - s->len;
135
136 ret = vsnprintf(s->buffer + s->len, len, fmt, args);
137
138 if (ret >= len) {
139 expand_buffer(s);
140 goto try_again;
141 }
142
143 s->len += ret;
144
145 return len;
146}
147
148/**
149 * trace_seq_puts - trace sequence printing of simple string
150 * @s: trace sequence descriptor
151 * @str: simple string to record
152 *
153 * The tracer may use either the sequence operations or its own
154 * copy to user routines. This function records a simple string
155 * into a special buffer (@s) for later retrieval by a sequencer
156 * or other mechanism.
157 */
158int trace_seq_puts(struct trace_seq *s, const char *str)
159{
160 int len;
161
162 TRACE_SEQ_CHECK(s);
163
164 len = strlen(str);
165
166 while (len > ((s->buffer_size - 1) - s->len))
167 expand_buffer(s);
168
169 memcpy(s->buffer + s->len, str, len);
170 s->len += len;
171
172 return len;
173}
174
175int trace_seq_putc(struct trace_seq *s, unsigned char c)
176{
177 TRACE_SEQ_CHECK(s);
178
179 while (s->len >= (s->buffer_size - 1))
180 expand_buffer(s);
181
182 s->buffer[s->len++] = c;
183
184 return 1;
185}
186
187void trace_seq_terminate(struct trace_seq *s)
188{
189 TRACE_SEQ_CHECK(s);
190
191 /* There's always one character left on the buffer */
192 s->buffer[s->len] = 0;
193}
194
195int trace_seq_do_printf(struct trace_seq *s)
196{
197 TRACE_SEQ_CHECK(s);
198 return printf("%.*s", s->len, s->buffer);
199}