Re: [PATCH 01/17] tools lib traceevent: Add state member to structtrace_seq
From: Arnaldo Carvalho de Melo
Date: Wed Jan 15 2014 - 09:21:10 EST
Em Wed, Jan 15, 2014 at 02:03:20PM +0900, Namhyung Kim escreveu:
> On Tue, 14 Jan 2014 21:56:55 -0500, Steven Rostedt wrote:
> > On Wed, 15 Jan 2014 11:49:28 +0900
> > Namhyung Kim <namhyung@xxxxxxxxxx> wrote:
> >> Oh, it looks better. But I'd like to TRACE_SEQ_CHECK() as is for some
> >> cases. How about this?
> >
> > Looks good to me.
> >
> > Acked-by: Steven Rostedt <rostedt@xxxxxxxxxxx>
> >
> > I'll try to look at the rest of the patches tomorrow.
Hi Steven, can I keep your ackd-by?
> Thanks, and I found that trace_seq_destroy() should use
> TRACE_SEQ_TRACE_RET instead. Here's an updated patch.
>
> Thanks,
> Namhyung
>
>
> From 539a5dd1cb3ba4cb03c283115a9a84f8e345514e Mon Sep 17 00:00:00 2001
> From: Namhyung Kim <namhyung@xxxxxxxxxx>
> Date: Thu, 19 Dec 2013 18:17:44 +0900
> Subject: [PATCH] tools lib traceevent: Add state member to struct trace_seq
>
> The trace_seq->state is for tracking errors during the use of
> trace_seq APIs and getting rid of die() in it.
>
> Acked-by: Steven Rostedt <rostedt@xxxxxxxxxxx>
> Signed-off-by: Namhyung Kim <namhyung@xxxxxxxxxx>
> ---
> tools/lib/traceevent/Makefile | 2 +-
> tools/lib/traceevent/event-parse.h | 7 +++++
> tools/lib/traceevent/trace-seq.c | 55 +++++++++++++++++++++++++++++---------
> 3 files changed, 50 insertions(+), 14 deletions(-)
>
> diff --git a/tools/lib/traceevent/Makefile b/tools/lib/traceevent/Makefile
> index f778d48ac609..56d52a33a3df 100644
> --- a/tools/lib/traceevent/Makefile
> +++ b/tools/lib/traceevent/Makefile
> @@ -136,7 +136,7 @@ export Q VERBOSE
>
> EVENT_PARSE_VERSION = $(EP_VERSION).$(EP_PATCHLEVEL).$(EP_EXTRAVERSION)
>
> -INCLUDES = -I. $(CONFIG_INCLUDES)
> +INCLUDES = -I. -I $(srctree)/../../include $(CONFIG_INCLUDES)
>
> # Set compile option CFLAGS if not set elsewhere
> CFLAGS ?= -g -Wall
> diff --git a/tools/lib/traceevent/event-parse.h b/tools/lib/traceevent/event-parse.h
> index cf5db9013f2c..3c890cb28db7 100644
> --- a/tools/lib/traceevent/event-parse.h
> +++ b/tools/lib/traceevent/event-parse.h
> @@ -58,6 +58,12 @@ struct pevent_record {
> #endif
> };
>
> +enum trace_seq_fail {
> + TRACE_SEQ__GOOD,
> + TRACE_SEQ__BUFFER_POISONED,
> + TRACE_SEQ__MEM_ALLOC_FAILED,
> +};
> +
> /*
> * Trace sequences are used to allow a function to call several other functions
> * to create a string of data to use (up to a max of PAGE_SIZE).
> @@ -68,6 +74,7 @@ struct trace_seq {
> unsigned int buffer_size;
> unsigned int len;
> unsigned int readpos;
> + enum trace_seq_fail state;
> };
>
> void trace_seq_init(struct trace_seq *s);
> diff --git a/tools/lib/traceevent/trace-seq.c b/tools/lib/traceevent/trace-seq.c
> index d7f2e68bc5b9..f7112138e6af 100644
> --- a/tools/lib/traceevent/trace-seq.c
> +++ b/tools/lib/traceevent/trace-seq.c
> @@ -22,6 +22,7 @@
> #include <string.h>
> #include <stdarg.h>
>
> +#include <asm/bug.h>
> #include "event-parse.h"
> #include "event-utils.h"
>
> @@ -32,10 +33,21 @@
> #define TRACE_SEQ_POISON ((void *)0xdeadbeef)
> #define TRACE_SEQ_CHECK(s) \
> do { \
> - if ((s)->buffer == TRACE_SEQ_POISON) \
> - die("Usage of trace_seq after it was destroyed"); \
> + 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
> @@ -46,6 +58,7 @@ void trace_seq_init(struct trace_seq *s)
> s->readpos = 0;
> s->buffer_size = TRACE_SEQ_BUF_SIZE;
> s->buffer = malloc_or_die(s->buffer_size);
> + s->state = TRACE_SEQ__GOOD;
> }
>
> /**
> @@ -71,7 +84,7 @@ void trace_seq_destroy(struct trace_seq *s)
> {
> if (!s)
> return;
> - TRACE_SEQ_CHECK(s);
> + TRACE_SEQ_CHECK_RET(s);
> free(s->buffer);
> s->buffer = TRACE_SEQ_POISON;
> }
> @@ -80,8 +93,9 @@ static void expand_buffer(struct trace_seq *s)
> {
> s->buffer_size += TRACE_SEQ_BUF_SIZE;
> s->buffer = realloc(s->buffer, s->buffer_size);
> - if (!s->buffer)
> - die("Can't allocate trace_seq buffer memory");
> + if (WARN_ONCE(!s->buffer,
> + "Can't allocate trace_seq buffer memory"))
> + s->state = TRACE_SEQ__MEM_ALLOC_FAILED;
> }
>
> /**
> @@ -105,9 +119,9 @@ trace_seq_printf(struct trace_seq *s, const char *fmt, ...)
> int len;
> int ret;
>
> - TRACE_SEQ_CHECK(s);
> -
> try_again:
> + TRACE_SEQ_CHECK_RET0(s);
> +
> len = (s->buffer_size - 1) - s->len;
>
> va_start(ap, fmt);
> @@ -141,9 +155,9 @@ trace_seq_vprintf(struct trace_seq *s, const char *fmt, va_list args)
> int len;
> int ret;
>
> - TRACE_SEQ_CHECK(s);
> -
> try_again:
> + TRACE_SEQ_CHECK_RET0(s);
> +
> len = (s->buffer_size - 1) - s->len;
>
> ret = vsnprintf(s->buffer + s->len, len, fmt, args);
> @@ -172,13 +186,15 @@ int trace_seq_puts(struct trace_seq *s, const char *str)
> {
> int len;
>
> - TRACE_SEQ_CHECK(s);
> + 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;
>
> @@ -187,11 +203,13 @@ int trace_seq_puts(struct trace_seq *s, const char *str)
>
> int trace_seq_putc(struct trace_seq *s, unsigned char c)
> {
> - TRACE_SEQ_CHECK(s);
> + 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;
> @@ -199,7 +217,7 @@ int trace_seq_putc(struct trace_seq *s, unsigned char c)
>
> void trace_seq_terminate(struct trace_seq *s)
> {
> - TRACE_SEQ_CHECK(s);
> + TRACE_SEQ_CHECK_RET(s);
>
> /* There's always one character left on the buffer */
> s->buffer[s->len] = 0;
> @@ -208,5 +226,16 @@ void trace_seq_terminate(struct trace_seq *s)
> int trace_seq_do_printf(struct trace_seq *s)
> {
> TRACE_SEQ_CHECK(s);
> - return printf("%.*s", s->len, s->buffer);
> +
> + switch (s->state) {
> + case TRACE_SEQ__GOOD:
> + return printf("%.*s", s->len, s->buffer);
> + case TRACE_SEQ__BUFFER_POISONED:
> + puts("Usage of trace_seq after it was destroyed");
> + break;
> + case TRACE_SEQ__MEM_ALLOC_FAILED:
> + puts("Can't allocate trace_seq buffer memory");
> + break;
> + }
> + return -1;
> }
> --
> 1.7.11.7
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