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.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Reviewed-by: Jiri Olsa <jolsa@redhat.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung.kim@lge.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/87fvopalbb.fsf@sejong.aot.lge.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

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;
 }