On Wed, 15 Jan 2014 10:45:24 +0900
Namhyung Kim <namhy...@kernel.org> wrote:
>
> @@ -32,8 +33,9 @@
> #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)
>
> /**
> @@ -46,6 +48,7 @@ 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;
> }
>
> /**
> @@ -80,8 +83,9 @@ 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;
> }
>
> /**
> @@ -108,6 +112,9 @@ trace_seq_printf(struct trace_seq *s, const char *fmt,
> ...)
> TRACE_SEQ_CHECK(s);
>
> try_again:
> + if (s->state != TRACE_SEQ__GOOD)
> + return 0;
> +
> len = (s->buffer_size - 1) - s->len;
>
> va_start(ap, fmt);
> @@ -144,6 +151,9 @@ trace_seq_vprintf(struct trace_seq *s, const char *fmt,
> va_list args)
> TRACE_SEQ_CHECK(s);
>
> try_again:
> + if (s->state != TRACE_SEQ__GOOD)
> + return 0;
> +
> len = (s->buffer_size - 1) - s->len;
>
> ret = vsnprintf(s->buffer + s->len, len, fmt, args);
> @@ -174,11 +184,17 @@ int trace_seq_puts(struct trace_seq *s, const char *str)
>
> TRACE_SEQ_CHECK(s);
>
> + if (s->state != TRACE_SEQ__GOOD)
> + return 0;
> +
> len = strlen(str);
>
> while (len > ((s->buffer_size - 1) - s->len))
> expand_buffer(s);
>
> + if (s->state != TRACE_SEQ__GOOD)
> + return 0;
> +
> memcpy(s->buffer + s->len, str, len);
> s->len += len;
>
> @@ -189,9 +205,15 @@ int trace_seq_putc(struct trace_seq *s, unsigned char c)
> {
> TRACE_SEQ_CHECK(s);
>
> + if (s->state != TRACE_SEQ__GOOD)
> + return 0;
> +
Instead of adding all of these, we can extend the macro
TRACE_SEQ_CHECK() which does a
if (s->state != TRACE_SEQ__GOOD)
return;
and a TRACE_SEQ_CHECK_RET() that does a return 0;
-- Steve
> while (s->len >= (s->buffer_size - 1))
> expand_buffer(s);
>
> + if (s->state != TRACE_SEQ__GOOD)
> + return 0;
> +
> s->buffer[s->len++] = c;
>
> return 1;
> @@ -201,6 +223,9 @@ void trace_seq_terminate(struct trace_seq *s)
> {
> TRACE_SEQ_CHECK(s);
>
> + if (s->state != TRACE_SEQ__GOOD)
> + return;
> +
> /* There's always one character left on the buffer */
> s->buffer[s->len] = 0;
> }
> @@ -208,5 +233,16 @@ 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;
> }
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
