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// SPDX-License-Identifier: LGPL-2.1
/*
* Copyright (C) 2009 Red Hat Inc, Steven Rostedt <srostedt@redhat.com>
*
*/
#include "trace-seq.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdarg.h>
#include <asm/bug.h>
#include "event-parse.h"
#include "event-utils.h"
/*
* The TRACE_SEQ_POISON is to catch the use of using
* a trace_seq structure after it was destroyed.
*/
#define TRACE_SEQ_POISON ((void *)0xdeadbeef)
#define TRACE_SEQ_CHECK(s) \
do { \
if (WARN_ONCE((s)->buffer == TRACE_SEQ_POISON, \
"Usage of trace_seq after it was destroyed")) \
(s)->state = TRACE_SEQ__BUFFER_POISONED; \
} while (0)
#define TRACE_SEQ_CHECK_RET_N(s, n) \
do { \
TRACE_SEQ_CHECK(s); \
if ((s)->state != TRACE_SEQ__GOOD) \
return n; \
} while (0)
#define TRACE_SEQ_CHECK_RET(s) TRACE_SEQ_CHECK_RET_N(s, )
#define TRACE_SEQ_CHECK_RET0(s) TRACE_SEQ_CHECK_RET_N(s, 0)
/**
* trace_seq_init - initialize the trace_seq structure
* @s: a pointer to the trace_seq structure to initialize
*/
void trace_seq_init(struct trace_seq *s)
{
s->len = 0;
s->readpos = 0;
s->buffer_size = TRACE_SEQ_BUF_SIZE;
s->buffer = malloc(s->buffer_size);
if (s->buffer != NULL)
s->state = TRACE_SEQ__GOOD;
else
s->state = TRACE_SEQ__MEM_ALLOC_FAILED;
}
/**
* trace_seq_reset - re-initialize the trace_seq structure
* @s: a pointer to the trace_seq structure to reset
*/
void trace_seq_reset(struct trace_seq *s)
{
if (!s)
return;
TRACE_SEQ_CHECK(s);
s->len = 0;
s->readpos = 0;
}
/**
* trace_seq_destroy - free up memory of a trace_seq
* @s: a pointer to the trace_seq to free the buffer
*
* Only frees the buffer, not the trace_seq struct itself.
*/
void trace_seq_destroy(struct trace_seq *s)
{
if (!s)
return;
TRACE_SEQ_CHECK_RET(s);
free(s->buffer);
s->buffer = TRACE_SEQ_POISON;
}
static void expand_buffer(struct trace_seq *s)
{
char *buf;
buf = realloc(s->buffer, s->buffer_size + TRACE_SEQ_BUF_SIZE);
if (WARN_ONCE(!buf, "Can't allocate trace_seq buffer memory")) {
s->state = TRACE_SEQ__MEM_ALLOC_FAILED;
return;
}
s->buffer = buf;
s->buffer_size += TRACE_SEQ_BUF_SIZE;
}
/**
* trace_seq_printf - sequence printing of trace information
* @s: trace sequence descriptor
* @fmt: printf format string
*
* It returns 0 if the trace oversizes the buffer's free
* space, 1 otherwise.
*
* The tracer may use either sequence operations or its own
* copy to user routines. To simplify formating of a trace
* trace_seq_printf is used to store strings into a special
* buffer (@s). Then the output may be either used by
* the sequencer or pulled into another buffer.
*/
int
trace_seq_printf(struct trace_seq *s, const char *fmt, ...)
{
va_list ap;
int len;
int ret;
try_again:
TRACE_SEQ_CHECK_RET0(s);
len = (s->buffer_size - 1) - s->len;
va_start(ap, fmt);
ret = vsnprintf(s->buffer + s->len, len, fmt, ap);
va_end(ap);
if (ret >= len) {
expand_buffer(s);
goto try_again;
}
s->len += ret;
return 1;
}
/**
* trace_seq_vprintf - sequence printing of trace information
* @s: trace sequence descriptor
* @fmt: printf format string
*
* The tracer may use either sequence operations or its own
* copy to user routines. To simplify formating of a trace
* trace_seq_printf is used to store strings into a special
* buffer (@s). Then the output may be either used by
* the sequencer or pulled into another buffer.
*/
int
trace_seq_vprintf(struct trace_seq *s, const char *fmt, va_list args)
{
int len;
int ret;
try_again:
TRACE_SEQ_CHECK_RET0(s);
len = (s->buffer_size - 1) - s->len;
ret = vsnprintf(s->buffer + s->len, len, fmt, args);
if (ret >= len) {
expand_buffer(s);
goto try_again;
}
s->len += ret;
return len;
}
/**
* trace_seq_puts - trace sequence printing of simple string
* @s: trace sequence descriptor
* @str: simple string to record
*
* The tracer may use either the sequence operations or its own
* copy to user routines. This function records a simple string
* into a special buffer (@s) for later retrieval by a sequencer
* or other mechanism.
*/
int trace_seq_puts(struct trace_seq *s, const char *str)
{
int len;
TRACE_SEQ_CHECK_RET0(s);
len = strlen(str);
while (len > ((s->buffer_size - 1) - s->len))
expand_buffer(s);
TRACE_SEQ_CHECK_RET0(s);
memcpy(s->buffer + s->len, str, len);
s->len += len;
return len;
}
int trace_seq_putc(struct trace_seq *s, unsigned char c)
{
TRACE_SEQ_CHECK_RET0(s);
while (s->len >= (s->buffer_size - 1))
expand_buffer(s);
TRACE_SEQ_CHECK_RET0(s);
s->buffer[s->len++] = c;
return 1;
}
void trace_seq_terminate(struct trace_seq *s)
{
TRACE_SEQ_CHECK_RET(s);
/* There's always one character left on the buffer */
s->buffer[s->len] = 0;
}
int trace_seq_do_fprintf(struct trace_seq *s, FILE *fp)
{
TRACE_SEQ_CHECK(s);
switch (s->state) {
case TRACE_SEQ__GOOD:
return fprintf(fp, "%.*s", s->len, s->buffer);
case TRACE_SEQ__BUFFER_POISONED:
fprintf(fp, "%s\n", "Usage of trace_seq after it was destroyed");
break;
case TRACE_SEQ__MEM_ALLOC_FAILED:
fprintf(fp, "%s\n", "Can't allocate trace_seq buffer memory");
break;
}
return -1;
}
int trace_seq_do_printf(struct trace_seq *s)
{
return trace_seq_do_fprintf(s, stdout);
}
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