1 /* 2 * Copyright (C) 2009 Red Hat Inc, Steven Rostedt <srostedt (at) 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) \ 34 do { \ 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 */ 43 void 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_reset - re-initialize the trace_seq structure 53 * @s: a pointer to the trace_seq structure to reset 54 */ 55 void trace_seq_reset(struct trace_seq *s) 56 { 57 if (!s) 58 return; 59 TRACE_SEQ_CHECK(s); 60 s->len = 0; 61 s->readpos = 0; 62 } 63 64 /** 65 * trace_seq_destroy - free up memory of a trace_seq 66 * @s: a pointer to the trace_seq to free the buffer 67 * 68 * Only frees the buffer, not the trace_seq struct itself. 69 */ 70 void trace_seq_destroy(struct trace_seq *s) 71 { 72 if (!s) 73 return; 74 TRACE_SEQ_CHECK(s); 75 free(s->buffer); 76 s->buffer = TRACE_SEQ_POISON; 77 } 78 79 static void expand_buffer(struct trace_seq *s) 80 { 81 s->buffer_size += TRACE_SEQ_BUF_SIZE; 82 s->buffer = realloc(s->buffer, s->buffer_size); 83 if (!s->buffer) 84 die("Can't allocate trace_seq buffer memory"); 85 } 86 87 /** 88 * trace_seq_printf - sequence printing of trace information 89 * @s: trace sequence descriptor 90 * @fmt: printf format string 91 * 92 * It returns 0 if the trace oversizes the buffer's free 93 * space, 1 otherwise. 94 * 95 * The tracer may use either sequence operations or its own 96 * copy to user routines. To simplify formating of a trace 97 * trace_seq_printf is used to store strings into a special 98 * buffer (@s). Then the output may be either used by 99 * the sequencer or pulled into another buffer. 100 */ 101 int 102 trace_seq_printf(struct trace_seq *s, const char *fmt, ...) 103 { 104 va_list ap; 105 int len; 106 int ret; 107 108 TRACE_SEQ_CHECK(s); 109 110 try_again: 111 len = (s->buffer_size - 1) - s->len; 112 113 va_start(ap, fmt); 114 ret = vsnprintf(s->buffer + s->len, len, fmt, ap); 115 va_end(ap); 116 117 if (ret >= len) { 118 expand_buffer(s); 119 goto try_again; 120 } 121 122 s->len += ret; 123 124 return 1; 125 } 126 127 /** 128 * trace_seq_vprintf - sequence printing of trace information 129 * @s: trace sequence descriptor 130 * @fmt: printf format string 131 * 132 * The tracer may use either sequence operations or its own 133 * copy to user routines. To simplify formating of a trace 134 * trace_seq_printf is used to store strings into a special 135 * buffer (@s). Then the output may be either used by 136 * the sequencer or pulled into another buffer. 137 */ 138 int 139 trace_seq_vprintf(struct trace_seq *s, const char *fmt, va_list args) 140 { 141 int len; 142 int ret; 143 144 TRACE_SEQ_CHECK(s); 145 146 try_again: 147 len = (s->buffer_size - 1) - s->len; 148 149 ret = vsnprintf(s->buffer + s->len, len, fmt, args); 150 151 if (ret >= len) { 152 expand_buffer(s); 153 goto try_again; 154 } 155 156 s->len += ret; 157 158 return len; 159 } 160 161 /** 162 * trace_seq_puts - trace sequence printing of simple string 163 * @s: trace sequence descriptor 164 * @str: simple string to record 165 * 166 * The tracer may use either the sequence operations or its own 167 * copy to user routines. This function records a simple string 168 * into a special buffer (@s) for later retrieval by a sequencer 169 * or other mechanism. 170 */ 171 int trace_seq_puts(struct trace_seq *s, const char *str) 172 { 173 int len; 174 175 TRACE_SEQ_CHECK(s); 176 177 len = strlen(str); 178 179 while (len > ((s->buffer_size - 1) - s->len)) 180 expand_buffer(s); 181 182 memcpy(s->buffer + s->len, str, len); 183 s->len += len; 184 185 return len; 186 } 187 188 int trace_seq_putc(struct trace_seq *s, unsigned char c) 189 { 190 TRACE_SEQ_CHECK(s); 191 192 while (s->len >= (s->buffer_size - 1)) 193 expand_buffer(s); 194 195 s->buffer[s->len++] = c; 196 197 return 1; 198 } 199 200 void trace_seq_terminate(struct trace_seq *s) 201 { 202 TRACE_SEQ_CHECK(s); 203 204 /* There's always one character left on the buffer */ 205 s->buffer[s->len] = 0; 206 } 207 208 int trace_seq_do_printf(struct trace_seq *s) 209 { 210 TRACE_SEQ_CHECK(s); 211 return printf("%.*s", s->len, s->buffer); 212 } 213
