[PATCH 4/4] tools lib traceevent: Get rid of die() finally!!

[Namhyung Kim]

From: Namhyung Kim <namhyu...@lge.com>

Now all of its users were gone. :)

Signed-off-by: Namhyung Kim <namh...@kernel.org>
---
tools/lib/traceevent/event-utils.h | 4 ----
tools/lib/traceevent/parse-utils.c | 44 --------------------------------------
2 files changed, 48 deletions(-)

diff --git a/tools/lib/traceevent/event-utils.h b/tools/lib/traceevent/event-utils.h
index e76c9acb92cd..d1dc2170e402 100644
--- a/tools/lib/traceevent/event-utils.h
+++ b/tools/lib/traceevent/event-utils.h
@@ -23,18 +23,14 @@
#include <ctype.h>

/* Can be overridden */
-void die(const char *fmt, ...);
-void *malloc_or_die(unsigned int size);
void warning(const char *fmt, ...);
void pr_stat(const char *fmt, ...);
void vpr_stat(const char *fmt, va_list ap);

/* Always available */
-void __die(const char *fmt, ...);
void __warning(const char *fmt, ...);
void __pr_stat(const char *fmt, ...);

-void __vdie(const char *fmt, ...);
void __vwarning(const char *fmt, ...);
void __vpr_stat(const char *fmt, ...);

diff --git a/tools/lib/traceevent/parse-utils.c b/tools/lib/traceevent/parse-utils.c
index bba701cf10e6..eda07fa31dca 100644
--- a/tools/lib/traceevent/parse-utils.c
+++ b/tools/lib/traceevent/parse-utils.c
@@ -25,40 +25,6 @@

#define __weak __attribute__((weak))

-void __vdie(const char *fmt, va_list ap)
-{
- int ret = errno;
-
- if (errno)
- perror("trace-cmd");
- else
- ret = -1;
-
- fprintf(stderr, " ");
- vfprintf(stderr, fmt, ap);
-
- fprintf(stderr, "\n");
- exit(ret);
-}
-
-void __die(const char *fmt, ...)
-{
- va_list ap;
-
- va_start(ap, fmt);
- __vdie(fmt, ap);
- va_end(ap);
-}
-
-void __weak die(const char *fmt, ...)
-{
- va_list ap;
-
- va_start(ap, fmt);
- __vdie(fmt, ap);
- va_end(ap);
-}
-
void __vwarning(const char *fmt, va_list ap)
{
if (errno)
@@ -117,13 +83,3 @@ void __weak pr_stat(const char *fmt, ...)
__vpr_stat(fmt, ap);
va_end(ap);
}
-
-void __weak *malloc_or_die(unsigned int size)
-{
- void *data;
-
- data = malloc(size);
- if (!data)
- die("malloc");
- return data;
-}
--
1.7.11.7

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[Namhyung Kim]

From: Namhyung Kim <namhyu...@lge.com>

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 <namh...@kernel.org>
---

tools/lib/traceevent/event-parse.h | 7 +++++++
tools/lib/traceevent/trace-seq.c | 41 ++++++++++++++++++++++++++++++++++----
2 files changed, 44 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..976ad2a146b3 100644
--- a/tools/lib/traceevent/trace-seq.c
+++ b/tools/lib/traceevent/trace-seq.c
@@ -32,8 +32,8 @@
#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 ((s)->buffer == TRACE_SEQ_POISON) \
+ (s)->state = TRACE_SEQ__BUFFER_POISONED; \
} while (0)

/**
@@ -46,6 +46,7 @@ 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 +82,7 @@ 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 +109,9 @@ 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 +148,9 @@ 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 +181,17 @@ 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 +202,15 @@ 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 +220,9 @@ 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 +230,16 @@ 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;

[Namhyung Kim]

From: Namhyung Kim <namhyu...@lge.com>

If realloc() fails, it'll leak the buffer. Also increate buffer size
only if the allocation succeeded.

Signed-off-by: Namhyung Kim <namh...@kernel.org>
---

tools/lib/traceevent/trace-seq.c | 12 +++++++++---
1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/tools/lib/traceevent/trace-seq.c b/tools/lib/traceevent/trace-seq.c
index 976ad2a146b3..57405652f26d 100644
--- a/tools/lib/traceevent/trace-seq.c
+++ b/tools/lib/traceevent/trace-seq.c
@@ -79,10 +79,16 @@ void trace_seq_destroy(struct trace_seq *s)

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)
+ char *buf;
+
+ buf = realloc(s->buffer, s->buffer_size + TRACE_SEQ_BUF_SIZE);
+ if (!buf) {
s->state = TRACE_SEQ__MEM_ALLOC_FAILED;
+ return;
+ }
+
+ s->buffer = buf;
+ s->buffer_size += TRACE_SEQ_BUF_SIZE;
}

/**

[Namhyung Kim]

From: Namhyung Kim <namhyu...@lge.com>

Use plain malloc() and check its return value.

Signed-off-by: Namhyung Kim <namh...@kernel.org>
---

tools/lib/traceevent/trace-seq.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/tools/lib/traceevent/trace-seq.c b/tools/lib/traceevent/trace-seq.c
index 57405652f26d..d24a33190bb8 100644
--- a/tools/lib/traceevent/trace-seq.c
+++ b/tools/lib/traceevent/trace-seq.c
@@ -45,8 +45,11 @@ void trace_seq_init(struct trace_seq *s)
s->len = 0;

s->readpos = 0;
s->buffer_size = TRACE_SEQ_BUF_SIZE;

- s->buffer = malloc_or_die(s->buffer_size);
- s->state = TRACE_SEQ__GOOD;
+ s->buffer = malloc(s->buffer_size);
+ if (s->buffer != NULL)

+ s->state = TRACE_SEQ__GOOD;

+ else

+ s->state = TRACE_SEQ__MEM_ALLOC_FAILED;
}

/**

[Namhyung Kim]

Ping!

[Jiri Olsa]

So unless we use trace_seq_do_printf we dont have any
notification that this went wrong..?

How about use some sort of WARN_ONCE any time the state
is set != GOOD ?

thanks,
jirka

[Namhyung Kim]

Hi Jiri,

Right.

>
> How about use some sort of WARN_ONCE any time the state
> is set != GOOD ?

I'm not sure what's the right thing to do for that case. Printing a
warning message might disturb user's output since it can be in a middle
of some (other) processing and she doesn't want to print anything during
the processing for some reason.

I just thought that it's not so important to print message so keeps the
error internally until it gets printed. But I can be wrong as usual...

Thanks,
Namhyung

[Jiri Olsa]

On Mon, Jan 06, 2014 at 04:44:18PM +0900, Namhyung Kim wrote:

SNIP

> >> + (s)->state = TRACE_SEQ__BUFFER_POISONED; \
> >
> > So unless we use trace_seq_do_printf we dont have any
> > notification that this went wrong..?
>
> Right.
>
> >
> > How about use some sort of WARN_ONCE any time the state
> > is set != GOOD ?
>
> I'm not sure what's the right thing to do for that case. Printing a
> warning message might disturb user's output since it can be in a middle
> of some (other) processing and she doesn't want to print anything during
> the processing for some reason.
>
> I just thought that it's not so important to print message so keeps the
> error internally until it gets printed. But I can be wrong as usual...

I think that if she manages to get one of those errors
the perf would fail soon anyway.. so it feels better
to print it out immediately.

jirka

[Steven Rostedt]

On Mon, 6 Jan 2014 15:38:28 +0100
Jiri Olsa <jo...@redhat.com> wrote:


> > I just thought that it's not so important to print message so keeps the
> > error internally until it gets printed. But I can be wrong as usual...
>
> I think that if she manages to get one of those errors
> the perf would fail soon anyway.. so it feels better
> to print it out immediately.

Yeah, using a trace_seq after it has been destroyed is a critical
failure, and a major bug. A print to the user console should not be a
problem here. And actually, crashing is not that bad either, as glibc
does the same with using free() of a freed pointer.

But as this error is major, an unwanted print is minor.

-- Steve

[Namhyung Kim]

Hi Steve and Jiri,

2014-01-06 PM 11:45, Steven Rostedt wrote:
> On Mon, 6 Jan 2014 15:38:28 +0100
> Jiri Olsa <jo...@redhat.com> wrote:
>
>
>>> I just thought that it's not so important to print message so keeps the
>>> error internally until it gets printed. But I can be wrong as usual...
>>
>> I think that if she manages to get one of those errors
>> the perf would fail soon anyway.. so it feels better
>> to print it out immediately.
>
> Yeah, using a trace_seq after it has been destroyed is a critical
> failure, and a major bug. A print to the user console should not be a
> problem here. And actually, crashing is not that bad either, as glibc
> does the same with using free() of a freed pointer.
>
> But as this error is major, an unwanted print is minor.

OK, I'll add the WARN_ONCE in the TRACE_SEQ_CHECK then.

Thanks,
Namhyung