* [PATCH v2] trace-cmd: Remove all die()s from trace-cmd library
@ 2021-03-24 13:51 Tzvetomir Stoyanov (VMware)
2021-03-24 21:53 ` Steven Rostedt
0 siblings, 1 reply; 3+ messages in thread
From: Tzvetomir Stoyanov (VMware) @ 2021-03-24 13:51 UTC (permalink / raw)
To: rostedt; +Cc: linux-trace-devel
The die() call is used for a fatal error. It terminates the current
program with exit(). The program should not be terminated from a library
routine, the die() call should not be used in the trace-cmd library
context.
But as all these logs indicate a fatal error in the library, it is
useful to have them. The die() call is replaced with _lib_fatal()
library internal function, which prints the error message without
terminating the application. If the library is compiled with
LIB_DIE
defined, the _lib_fatal() call behaves like die() - calls exit() to
terminate the application.
Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com>
---
v2 changes:
- Replaced die() with _lib_fatal().
lib/trace-cmd/include/trace-cmd-local.h | 2 ++
lib/trace-cmd/trace-input.c | 29 +++++++++++++-------
lib/trace-cmd/trace-util.c | 36 ++++++++++++-------------
3 files changed, 38 insertions(+), 29 deletions(-)
diff --git a/lib/trace-cmd/include/trace-cmd-local.h b/lib/trace-cmd/include/trace-cmd-local.h
index d265e4c8..da9d8d58 100644
--- a/lib/trace-cmd/include/trace-cmd-local.h
+++ b/lib/trace-cmd/include/trace-cmd-local.h
@@ -12,6 +12,8 @@
/* Can be overridden */
void warning(const char *fmt, ...);
+void _lib_fatal(const char *fmt, ...);
+
#define __packed __attribute__((packed))
/* trace.dat file format version */
diff --git a/lib/trace-cmd/trace-input.c b/lib/trace-cmd/trace-input.c
index 2093a3dc..3687de09 100644
--- a/lib/trace-cmd/trace-input.c
+++ b/lib/trace-cmd/trace-input.c
@@ -16,6 +16,7 @@
#include <linux/time64.h>
#include "trace-write-local.h"
+#include "trace-cmd-local.h"
#include "trace-local.h"
#include "kbuffer.h"
#include "list.h"
@@ -1087,8 +1088,10 @@ static void __free_page(struct tracecmd_input *handle, struct page *page)
struct page **pages;
int index;
- if (!page->ref_count)
- die("Page ref count is zero!\n");
+ if (!page->ref_count) {
+ _lib_fatal("Page ref count is zero!\n");
+ return;
+ }
page->ref_count--;
if (page->ref_count)
@@ -1146,16 +1149,20 @@ void tracecmd_free_record(struct tep_record *record)
if (!record)
return;
- if (!record->ref_count)
- die("record ref count is zero!");
+ if (!record->ref_count) {
+ _lib_fatal("record ref count is zero!");
+ return;
+ }
record->ref_count--;
if (record->ref_count)
return;
- if (record->locked)
- die("freeing record when it is locked!");
+ if (record->locked) {
+ _lib_fatal("freeing record when it is locked!");
+ return;
+ }
record->data = NULL;
@@ -1318,7 +1325,7 @@ static int get_page(struct tracecmd_input *handle, int cpu,
if (offset & (handle->page_size - 1)) {
errno = -EINVAL;
- die("bad page offset %llx", offset);
+ _lib_fatal("bad page offset %llx", offset);
return -1;
}
@@ -1326,7 +1333,7 @@ static int get_page(struct tracecmd_input *handle, int cpu,
offset > handle->cpu_data[cpu].file_offset +
handle->cpu_data[cpu].file_size) {
errno = -EINVAL;
- die("bad page offset %llx", offset);
+ _lib_fatal("bad page offset %llx", offset);
return -1;
}
@@ -1891,8 +1898,10 @@ tracecmd_peek_data(struct tracecmd_input *handle, int cpu)
if (handle->cpu_data[cpu].next) {
record = handle->cpu_data[cpu].next;
- if (!record->data)
- die("Something freed the record");
+ if (!record->data) {
+ _lib_fatal("Something freed the record");
+ return NULL;
+ }
if (handle->cpu_data[cpu].timestamp == record->ts)
return record;
diff --git a/lib/trace-cmd/trace-util.c b/lib/trace-cmd/trace-util.c
index 538adbc2..e8ed22fa 100644
--- a/lib/trace-cmd/trace-util.c
+++ b/lib/trace-cmd/trace-util.c
@@ -353,12 +353,12 @@ trace_load_plugins(struct tep_handle *tep, int flags)
return list;
}
-void __noreturn __vdie(const char *fmt, va_list ap)
+int __vlib_fatal(const char *fmt, va_list ap)
{
int ret = errno;
if (errno)
- perror("trace-cmd");
+ perror("libtracecmd");
else
ret = -1;
@@ -366,36 +366,32 @@ void __noreturn __vdie(const char *fmt, va_list ap)
vfprintf(stderr, fmt, ap);
fprintf(stderr, "\n");
- exit(ret);
+ return ret;
}
-void __noreturn __die(const char *fmt, ...)
+#ifdef LIB_DIE
+
+void __noreturn _lib_fatal(const char *fmt, ...)
{
va_list ap;
+ int ret;
va_start(ap, fmt);
- __vdie(fmt, ap);
+ ret = __vlib_fatal(fmt, ap);
va_end(ap);
+ exit(ret);
}
-void __weak __noreturn die(const char *fmt, ...)
+#else
+void _lib_fatal(const char *fmt, ...)
{
va_list ap;
va_start(ap, fmt);
- __vdie(fmt, ap);
+ __vlib_fatal(fmt, ap);
va_end(ap);
}
-
-void __weak *malloc_or_die(unsigned int size)
-{
- void *data;
-
- data = malloc(size);
- if (!data)
- die("malloc");
- return data;
-}
+#endif
#define LOG_BUF_SIZE 1024
static void __plog(const char *prefix, const char *fmt, va_list ap, FILE *fp)
@@ -546,8 +542,10 @@ int tracecmd_count_cpus(void)
pbuf = buf;
fp = fopen("/proc/cpuinfo", "r");
- if (!fp)
- die("Can not read cpuinfo");
+ if (!fp) {
+ _lib_fatal("Can not read cpuinfo");
+ return 0;
+ }
while ((r = getline(&pbuf, pn, fp)) >= 0) {
char *p;
--
2.30.2
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH v2] trace-cmd: Remove all die()s from trace-cmd library
2021-03-24 13:51 [PATCH v2] trace-cmd: Remove all die()s from trace-cmd library Tzvetomir Stoyanov (VMware)
@ 2021-03-24 21:53 ` Steven Rostedt
2021-03-25 7:50 ` Tzvetomir Stoyanov
0 siblings, 1 reply; 3+ messages in thread
From: Steven Rostedt @ 2021-03-24 21:53 UTC (permalink / raw)
To: Tzvetomir Stoyanov (VMware); +Cc: linux-trace-devel
On Wed, 24 Mar 2021 15:51:43 +0200
"Tzvetomir Stoyanov (VMware)" <tz.stoyanov@gmail.com> wrote:
> @@ -366,36 +366,32 @@ void __noreturn __vdie(const char *fmt, va_list ap)
> vfprintf(stderr, fmt, ap);
>
> fprintf(stderr, "\n");
> - exit(ret);
> + return ret;
> }
>
> -void __noreturn __die(const char *fmt, ...)
> +#ifdef LIB_DIE
I wonder if it would be more useful not to have it as a compile time
define, but instead a global variable:
static bool lib_die;
void tracecmd_die_on_error(void)
{
lib_die = true;
}
Make the "die()" functions into static variables here.
void __hidden _lib_fatal(const char *fmt, ...)
{
va_list ap;
va_start(ap, fmt);
if (lib_die)
__vdie(fmt, ap);
else
__vwarning(fmt, ap);
va_end(ap);
}
That way if we run trace-cmd with the --debug option, it could then call
the tracecmd_die_on_error() function, and it will crash on any "fatal"
places.
-- Steve
> +
> +void __noreturn _lib_fatal(const char *fmt, ...)
> {
> va_list ap;
> + int ret;
>
> va_start(ap, fmt);
> - __vdie(fmt, ap);
> + ret = __vlib_fatal(fmt, ap);
> va_end(ap);
> + exit(ret);
> }
>
> -void __weak __noreturn die(const char *fmt, ...)
> +#else
> +void _lib_fatal(const char *fmt, ...)
> {
> va_list ap;
>
> va_start(ap, fmt);
> - __vdie(fmt, ap);
> + __vlib_fatal(fmt, ap);
> va_end(ap);
> }
> -
> -void __weak *malloc_or_die(unsigned int size)
> -{
> - void *data;
> -
> - data = malloc(size);
> - if (!data)
> - die("malloc");
> - return data;
> -}
> +#endif
>
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH v2] trace-cmd: Remove all die()s from trace-cmd library
2021-03-24 21:53 ` Steven Rostedt
@ 2021-03-25 7:50 ` Tzvetomir Stoyanov
0 siblings, 0 replies; 3+ messages in thread
From: Tzvetomir Stoyanov @ 2021-03-25 7:50 UTC (permalink / raw)
To: Steven Rostedt; +Cc: Linux Trace Devel
On Wed, Mar 24, 2021 at 11:53 PM Steven Rostedt <rostedt@goodmis.org> wrote:
>
> On Wed, 24 Mar 2021 15:51:43 +0200
> "Tzvetomir Stoyanov (VMware)" <tz.stoyanov@gmail.com> wrote:
>
> > @@ -366,36 +366,32 @@ void __noreturn __vdie(const char *fmt, va_list ap)
> > vfprintf(stderr, fmt, ap);
> >
> > fprintf(stderr, "\n");
> > - exit(ret);
> > + return ret;
> > }
> >
> > -void __noreturn __die(const char *fmt, ...)
> > +#ifdef LIB_DIE
>
> I wonder if it would be more useful not to have it as a compile time
> define, but instead a global variable:
>
> static bool lib_die;
>
> void tracecmd_die_on_error(void)
> {
> lib_die = true;
> }
>
There is tracecmd_set_debug() API already, It can be used to trigger
that die() logic. It makes sense for the library to do a real die()
when running in debug mode, if a fatal error is encountered.
> Make the "die()" functions into static variables here.
>
> void __hidden _lib_fatal(const char *fmt, ...)
> {
> va_list ap;
>
> va_start(ap, fmt);
> if (lib_die)
> __vdie(fmt, ap);
> else
> __vwarning(fmt, ap);
> va_end(ap);
> }
>
> That way if we run trace-cmd with the --debug option, it could then call
> the tracecmd_die_on_error() function, and it will crash on any "fatal"
> places.
>
> -- Steve
>
>
> > +
> > +void __noreturn _lib_fatal(const char *fmt, ...)
> > {
> > va_list ap;
> > + int ret;
> >
> > va_start(ap, fmt);
> > - __vdie(fmt, ap);
> > + ret = __vlib_fatal(fmt, ap);
> > va_end(ap);
> > + exit(ret);
> > }
> >
> > -void __weak __noreturn die(const char *fmt, ...)
> > +#else
> > +void _lib_fatal(const char *fmt, ...)
> > {
> > va_list ap;
> >
> > va_start(ap, fmt);
> > - __vdie(fmt, ap);
> > + __vlib_fatal(fmt, ap);
> > va_end(ap);
> > }
> > -
> > -void __weak *malloc_or_die(unsigned int size)
> > -{
> > - void *data;
> > -
> > - data = malloc(size);
> > - if (!data)
> > - die("malloc");
> > - return data;
> > -}
> > +#endif
> >
--
Tzvetomir (Ceco) Stoyanov
VMware Open Source Technology Center
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2021-03-24 13:51 [PATCH v2] trace-cmd: Remove all die()s from trace-cmd library Tzvetomir Stoyanov (VMware)
2021-03-24 21:53 ` Steven Rostedt
2021-03-25 7:50 ` Tzvetomir Stoyanov
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