Messages in this thread Patch in this message | | | From | Namhyung Kim <> | Subject | [PATCH 2/5] tools lib traceevent: Add state member to struct trace_seq | Date | Tue, 7 Jan 2014 12:00:09 +0900 |
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The trace_seq->state is for tracking errors during the use of trace_seq APIs and getting rid of die() in it.
Signed-off-by: Namhyung Kim <namhyung@kernel.org> --- tools/lib/traceevent/event-parse.h | 7 +++++++ tools/lib/traceevent/trace-seq.c | 42 ++++++++++++++++++++++++++++++++++---- 2 files changed, 45 insertions(+), 4 deletions(-)
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..1747aa50ecb0 100644 --- a/tools/lib/traceevent/trace-seq.c +++ b/tools/lib/traceevent/trace-seq.c @@ -32,8 +32,9 @@ #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 +47,7 @@ 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; } /** @@ -81,7 +83,7 @@ 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"); + s->state = TRACE_SEQ__MEM_ALLOC_FAILED; } /** @@ -108,6 +110,9 @@ 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 +149,9 @@ 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 +182,17 @@ 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 +203,15 @@ int trace_seq_putc(struct trace_seq *s, unsigned char c) { TRACE_SEQ_CHECK(s); + if (s->state != TRACE_SEQ__GOOD) + return 0; + 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 +221,9 @@ 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 +231,16 @@ 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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