--- /dev/null
+/*
+ * Copyright (C) 2009 Red Hat Inc, Steven Rostedt <srostedt@redhat.com>
+ *
+ * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation;
+ * version 2.1 of the License (not later!)
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this program; if not, see <http://www.gnu.org/licenses>
+ *
+ * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ */
+#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);
+}
Code Review / kvmfornfv.git / blobdiff