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