blob: f7112138e6af99808ac5bb010bb4b6c82e34ea03 [file] [log] [blame]
Steven Rostedtf7d82352012-04-06 00:47:53 +02001/*
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
Jon Stanley7b9f6b42012-09-07 16:32:46 -040016 * License along with this program; if not, see <http://www.gnu.org/licenses>
Steven Rostedtf7d82352012-04-06 00:47:53 +020017 *
18 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
19 */
20#include <stdio.h>
21#include <stdlib.h>
22#include <string.h>
23#include <stdarg.h>
24
Namhyung Kim3c6d8d82013-12-19 18:17:44 +090025#include <asm/bug.h>
Steven Rostedtf7d82352012-04-06 00:47:53 +020026#include "event-parse.h"
Steven Rostedt668fe012012-04-06 00:47:55 +020027#include "event-utils.h"
Steven Rostedtf7d82352012-04-06 00:47:53 +020028
29/*
30 * The TRACE_SEQ_POISON is to catch the use of using
31 * a trace_seq structure after it was destroyed.
32 */
33#define TRACE_SEQ_POISON ((void *)0xdeadbeef)
34#define TRACE_SEQ_CHECK(s) \
35do { \
Namhyung Kim3c6d8d82013-12-19 18:17:44 +090036 if (WARN_ONCE((s)->buffer == TRACE_SEQ_POISON, \
37 "Usage of trace_seq after it was destroyed")) \
38 (s)->state = TRACE_SEQ__BUFFER_POISONED; \
Steven Rostedtf7d82352012-04-06 00:47:53 +020039} while (0)
40
Namhyung Kim3c6d8d82013-12-19 18:17:44 +090041#define TRACE_SEQ_CHECK_RET_N(s, n) \
42do { \
43 TRACE_SEQ_CHECK(s); \
44 if ((s)->state != TRACE_SEQ__GOOD) \
45 return n; \
46} while (0)
47
48#define TRACE_SEQ_CHECK_RET(s) TRACE_SEQ_CHECK_RET_N(s, )
49#define TRACE_SEQ_CHECK_RET0(s) TRACE_SEQ_CHECK_RET_N(s, 0)
50
Steven Rostedtf7d82352012-04-06 00:47:53 +020051/**
52 * trace_seq_init - initialize the trace_seq structure
53 * @s: a pointer to the trace_seq structure to initialize
54 */
55void trace_seq_init(struct trace_seq *s)
56{
57 s->len = 0;
58 s->readpos = 0;
59 s->buffer_size = TRACE_SEQ_BUF_SIZE;
60 s->buffer = malloc_or_die(s->buffer_size);
Namhyung Kim3c6d8d82013-12-19 18:17:44 +090061 s->state = TRACE_SEQ__GOOD;
Steven Rostedtf7d82352012-04-06 00:47:53 +020062}
63
64/**
Namhyung Kim6a48aec2013-06-04 14:20:19 +090065 * trace_seq_reset - re-initialize the trace_seq structure
66 * @s: a pointer to the trace_seq structure to reset
67 */
68void trace_seq_reset(struct trace_seq *s)
69{
70 if (!s)
71 return;
72 TRACE_SEQ_CHECK(s);
73 s->len = 0;
74 s->readpos = 0;
75}
76
77/**
Steven Rostedtf7d82352012-04-06 00:47:53 +020078 * trace_seq_destroy - free up memory of a trace_seq
79 * @s: a pointer to the trace_seq to free the buffer
80 *
81 * Only frees the buffer, not the trace_seq struct itself.
82 */
83void trace_seq_destroy(struct trace_seq *s)
84{
85 if (!s)
86 return;
Namhyung Kim3c6d8d82013-12-19 18:17:44 +090087 TRACE_SEQ_CHECK_RET(s);
Steven Rostedtf7d82352012-04-06 00:47:53 +020088 free(s->buffer);
89 s->buffer = TRACE_SEQ_POISON;
90}
91
92static void expand_buffer(struct trace_seq *s)
93{
94 s->buffer_size += TRACE_SEQ_BUF_SIZE;
95 s->buffer = realloc(s->buffer, s->buffer_size);
Namhyung Kim3c6d8d82013-12-19 18:17:44 +090096 if (WARN_ONCE(!s->buffer,
97 "Can't allocate trace_seq buffer memory"))
98 s->state = TRACE_SEQ__MEM_ALLOC_FAILED;
Steven Rostedtf7d82352012-04-06 00:47:53 +020099}
100
101/**
102 * trace_seq_printf - sequence printing of trace information
103 * @s: trace sequence descriptor
104 * @fmt: printf format string
105 *
106 * It returns 0 if the trace oversizes the buffer's free
107 * space, 1 otherwise.
108 *
109 * The tracer may use either sequence operations or its own
110 * copy to user routines. To simplify formating of a trace
111 * trace_seq_printf is used to store strings into a special
112 * buffer (@s). Then the output may be either used by
113 * the sequencer or pulled into another buffer.
114 */
115int
116trace_seq_printf(struct trace_seq *s, const char *fmt, ...)
117{
118 va_list ap;
119 int len;
120 int ret;
121
Steven Rostedtf7d82352012-04-06 00:47:53 +0200122 try_again:
Namhyung Kim3c6d8d82013-12-19 18:17:44 +0900123 TRACE_SEQ_CHECK_RET0(s);
124
Steven Rostedtf7d82352012-04-06 00:47:53 +0200125 len = (s->buffer_size - 1) - s->len;
126
127 va_start(ap, fmt);
128 ret = vsnprintf(s->buffer + s->len, len, fmt, ap);
129 va_end(ap);
130
131 if (ret >= len) {
132 expand_buffer(s);
133 goto try_again;
134 }
135
136 s->len += ret;
137
138 return 1;
139}
140
141/**
142 * trace_seq_vprintf - sequence printing of trace information
143 * @s: trace sequence descriptor
144 * @fmt: printf format string
145 *
146 * The tracer may use either sequence operations or its own
147 * copy to user routines. To simplify formating of a trace
148 * trace_seq_printf is used to store strings into a special
149 * buffer (@s). Then the output may be either used by
150 * the sequencer or pulled into another buffer.
151 */
152int
153trace_seq_vprintf(struct trace_seq *s, const char *fmt, va_list args)
154{
155 int len;
156 int ret;
157
Steven Rostedtf7d82352012-04-06 00:47:53 +0200158 try_again:
Namhyung Kim3c6d8d82013-12-19 18:17:44 +0900159 TRACE_SEQ_CHECK_RET0(s);
160
Steven Rostedtf7d82352012-04-06 00:47:53 +0200161 len = (s->buffer_size - 1) - s->len;
162
163 ret = vsnprintf(s->buffer + s->len, len, fmt, args);
164
165 if (ret >= len) {
166 expand_buffer(s);
167 goto try_again;
168 }
169
170 s->len += ret;
171
172 return len;
173}
174
175/**
176 * trace_seq_puts - trace sequence printing of simple string
177 * @s: trace sequence descriptor
178 * @str: simple string to record
179 *
180 * The tracer may use either the sequence operations or its own
181 * copy to user routines. This function records a simple string
182 * into a special buffer (@s) for later retrieval by a sequencer
183 * or other mechanism.
184 */
185int trace_seq_puts(struct trace_seq *s, const char *str)
186{
187 int len;
188
Namhyung Kim3c6d8d82013-12-19 18:17:44 +0900189 TRACE_SEQ_CHECK_RET0(s);
Steven Rostedtf7d82352012-04-06 00:47:53 +0200190
191 len = strlen(str);
192
193 while (len > ((s->buffer_size - 1) - s->len))
194 expand_buffer(s);
195
Namhyung Kim3c6d8d82013-12-19 18:17:44 +0900196 TRACE_SEQ_CHECK_RET0(s);
197
Steven Rostedtf7d82352012-04-06 00:47:53 +0200198 memcpy(s->buffer + s->len, str, len);
199 s->len += len;
200
201 return len;
202}
203
204int trace_seq_putc(struct trace_seq *s, unsigned char c)
205{
Namhyung Kim3c6d8d82013-12-19 18:17:44 +0900206 TRACE_SEQ_CHECK_RET0(s);
Steven Rostedtf7d82352012-04-06 00:47:53 +0200207
208 while (s->len >= (s->buffer_size - 1))
209 expand_buffer(s);
210
Namhyung Kim3c6d8d82013-12-19 18:17:44 +0900211 TRACE_SEQ_CHECK_RET0(s);
212
Steven Rostedtf7d82352012-04-06 00:47:53 +0200213 s->buffer[s->len++] = c;
214
215 return 1;
216}
217
218void trace_seq_terminate(struct trace_seq *s)
219{
Namhyung Kim3c6d8d82013-12-19 18:17:44 +0900220 TRACE_SEQ_CHECK_RET(s);
Steven Rostedtf7d82352012-04-06 00:47:53 +0200221
222 /* There's always one character left on the buffer */
223 s->buffer[s->len] = 0;
224}
225
226int trace_seq_do_printf(struct trace_seq *s)
227{
228 TRACE_SEQ_CHECK(s);
Namhyung Kim3c6d8d82013-12-19 18:17:44 +0900229
230 switch (s->state) {
231 case TRACE_SEQ__GOOD:
232 return printf("%.*s", s->len, s->buffer);
233 case TRACE_SEQ__BUFFER_POISONED:
234 puts("Usage of trace_seq after it was destroyed");
235 break;
236 case TRACE_SEQ__MEM_ALLOC_FAILED:
237 puts("Can't allocate trace_seq buffer memory");
238 break;
239 }
240 return -1;
Steven Rostedtf7d82352012-04-06 00:47:53 +0200241}