Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
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, write to the Free Software
17 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
20 */
21#include <stdio.h>
22#include <stdlib.h>
23#include <string.h>
24#include <stdarg.h>
25
26#include "event-parse.h"
27#include "event-utils.h"
28
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 { \
36 if ((s)->buffer == TRACE_SEQ_POISON) \
37 die("Usage of trace_seq after it was destroyed"); \
38} while (0)
39
40/**
41 * trace_seq_init - initialize the trace_seq structure
42 * @s: a pointer to the trace_seq structure to initialize
43 */
44void trace_seq_init(struct trace_seq *s)
45{
46 s->len = 0;
47 s->readpos = 0;
48 s->buffer_size = TRACE_SEQ_BUF_SIZE;
49 s->buffer = malloc_or_die(s->buffer_size);
50}
51
52/**
53 * trace_seq_destroy - free up memory of a trace_seq
54 * @s: a pointer to the trace_seq to free the buffer
55 *
56 * Only frees the buffer, not the trace_seq struct itself.
57 */
58void trace_seq_destroy(struct trace_seq *s)
59{
60 if (!s)
61 return;
62 TRACE_SEQ_CHECK(s);
63 free(s->buffer);
64 s->buffer = TRACE_SEQ_POISON;
65}
66
67static void expand_buffer(struct trace_seq *s)
68{
69 s->buffer_size += TRACE_SEQ_BUF_SIZE;
70 s->buffer = realloc(s->buffer, s->buffer_size);
71 if (!s->buffer)
72 die("Can't allocate trace_seq buffer memory");
73}
74
75/**
76 * trace_seq_printf - sequence printing of trace information
77 * @s: trace sequence descriptor
78 * @fmt: printf format string
79 *
80 * It returns 0 if the trace oversizes the buffer's free
81 * space, 1 otherwise.
82 *
83 * The tracer may use either sequence operations or its own
84 * copy to user routines. To simplify formating of a trace
85 * trace_seq_printf is used to store strings into a special
86 * buffer (@s). Then the output may be either used by
87 * the sequencer or pulled into another buffer.
88 */
89int
90trace_seq_printf(struct trace_seq *s, const char *fmt, ...)
91{
92 va_list ap;
93 int len;
94 int ret;
95
96 TRACE_SEQ_CHECK(s);
97
98 try_again:
99 len = (s->buffer_size - 1) - s->len;
100
101 va_start(ap, fmt);
102 ret = vsnprintf(s->buffer + s->len, len, fmt, ap);
103 va_end(ap);
104
105 if (ret >= len) {
106 expand_buffer(s);
107 goto try_again;
108 }
109
110 s->len += ret;
111
112 return 1;
113}
114
115/**
116 * trace_seq_vprintf - sequence printing of trace information
117 * @s: trace sequence descriptor
118 * @fmt: printf format string
119 *
120 * The tracer may use either sequence operations or its own
121 * copy to user routines. To simplify formating of a trace
122 * trace_seq_printf is used to store strings into a special
123 * buffer (@s). Then the output may be either used by
124 * the sequencer or pulled into another buffer.
125 */
126int
127trace_seq_vprintf(struct trace_seq *s, const char *fmt, va_list args)
128{
129 int len;
130 int ret;
131
132 TRACE_SEQ_CHECK(s);
133
134 try_again:
135 len = (s->buffer_size - 1) - s->len;
136
137 ret = vsnprintf(s->buffer + s->len, len, fmt, args);
138
139 if (ret >= len) {
140 expand_buffer(s);
141 goto try_again;
142 }
143
144 s->len += ret;
145
146 return len;
147}
148
149/**
150 * trace_seq_puts - trace sequence printing of simple string
151 * @s: trace sequence descriptor
152 * @str: simple string to record
153 *
154 * The tracer may use either the sequence operations or its own
155 * copy to user routines. This function records a simple string
156 * into a special buffer (@s) for later retrieval by a sequencer
157 * or other mechanism.
158 */
159int trace_seq_puts(struct trace_seq *s, const char *str)
160{
161 int len;
162
163 TRACE_SEQ_CHECK(s);
164
165 len = strlen(str);
166
167 while (len > ((s->buffer_size - 1) - s->len))
168 expand_buffer(s);
169
170 memcpy(s->buffer + s->len, str, len);
171 s->len += len;
172
173 return len;
174}
175
176int trace_seq_putc(struct trace_seq *s, unsigned char c)
177{
178 TRACE_SEQ_CHECK(s);
179
180 while (s->len >= (s->buffer_size - 1))
181 expand_buffer(s);
182
183 s->buffer[s->len++] = c;
184
185 return 1;
186}
187
188void trace_seq_terminate(struct trace_seq *s)
189{
190 TRACE_SEQ_CHECK(s);
191
192 /* There's always one character left on the buffer */
193 s->buffer[s->len] = 0;
194}
195
196int trace_seq_do_printf(struct trace_seq *s)
197{
198 TRACE_SEQ_CHECK(s);
199 return printf("%.*s", s->len, s->buffer);
200}