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Diffstat (limited to 'tools/lib/traceevent/trace-seq.c')
| -rw-r--r-- | tools/lib/traceevent/trace-seq.c | 249 |
1 files changed, 249 insertions, 0 deletions
diff --git a/tools/lib/traceevent/trace-seq.c b/tools/lib/traceevent/trace-seq.c new file mode 100644 index 000000000..8d5ecd2bf --- /dev/null +++ b/tools/lib/traceevent/trace-seq.c @@ -0,0 +1,249 @@ +// 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, the number of characters printed, or a negative + * value in case of an error. + * + * 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; + } + + if (ret > 0) + s->len += ret; + + return ret; +} + +/** + * trace_seq_vprintf - 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, the number of characters printed, or a negative + * value in case of an error. + * * + * 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; + } + + if (ret > 0) + s->len += ret; + + return ret; +} + +/** + * 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); +} |