[LTP] [PATCH v2 1/3] hotplug/memory_hotplug: Handle NULL returned by strtok_r when parsing inputs

[LTP] [PATCH v2 1/3] hotplug/memory_hotplug: Handle NULL returned by strtok_r when parsing inputs

[Yuan Gao]

In the original version of memtoy, it uses strtok_r(args, " ", &nextarg)
to split string. When strtok_r finds the last substring to be split,
it will set nextarg to NULL rather than let it point to '\0'.
In this case, if it wants to do something else to nextarg like calling
strspn(nextarg, " "), it will throw an error.
Add NULL check for nextarg to fix this error.

Change from v1
1. Replace strlen() with strnlen()

Signed-off-by: Yuan Gao <aiden.gaoyuan@gmail.com>
---
 .../kernel/hotplug/memory_hotplug/commands.c  | 31 +++++++++++--------
 1 file changed, 18 insertions(+), 13 deletions(-)

diff --git a/testcases/kernel/hotplug/memory_hotplug/commands.c b/testcases/kernel/hotplug/memory_hotplug/commands.c
index e31743bd3..e3438e132 100644
--- a/testcases/kernel/hotplug/memory_hotplug/commands.c
+++ b/testcases/kernel/hotplug/memory_hotplug/commands.c
@@ -50,6 +50,7 @@
 
 #define CMD_SUCCESS 0
 #define CMD_ERROR   1
+#define CMDBUFSZ 256
 
 #ifndef __NR_migrate_pages
 #define __NR_migrate_pages 0
@@ -61,6 +62,11 @@
 
 static char *whitespace = " \t";
 
+inline char *get_next_arg(char *args, char *nextarg)
+{
+	return nextarg ? nextarg + strspn(nextarg, whitespace) : args + strnlen(args, CMDBUFSZ);
+}
+
 /*
  * =========================================================================
  */
@@ -146,7 +152,7 @@ static int get_range(char *args, range_t * range, char **nextarg)
 		range->offset = get_scaled_value(args, "offset");
 		if (range->offset == BOGUS_SIZE)
 			return CMD_ERROR;
-		args = nextarg + strspn(nextarg, whitespace);
+		args = get_next_arg(args, nextarg);
 
 		/*
 		 * <length> ... only if offset specified
@@ -160,7 +166,7 @@ static int get_range(char *args, range_t * range, char **nextarg)
 					return CMD_ERROR;
 			} else
 				range->length = 0;	/* map to end of file */
-			args = nextarg + strspn(nextarg, whitespace);
+			args = get_next_arg(args, nextarg);
 		}
 	}
 
@@ -669,7 +675,7 @@ static int anon_seg(char *args)
 	range.length = get_scaled_value(args, "size");
 	if (range.length == BOGUS_SIZE)
 		return CMD_ERROR;
-	args = nextarg + strspn(nextarg, whitespace);
+	args = get_next_arg(args, nextarg);
 
 	if (*args != '\0') {
 		segflag = get_shared(args);
@@ -699,7 +705,7 @@ static int file_seg(char *args)
 	if (!required_arg(args, "<path-name>"))
 		return CMD_ERROR;
 	pathname = strtok_r(args, whitespace, &nextarg);
-	args = nextarg + strspn(nextarg, whitespace);
+	args = get_next_arg(args, nextarg);
 
 	/*
 	 * offset, length are optional
@@ -757,7 +763,7 @@ static int touch_seg(char *args)
 	if (!required_arg(args, "<seg-name>"))
 		return CMD_ERROR;
 	segname = strtok_r(args, whitespace, &nextarg);
-	args = nextarg + strspn(nextarg, whitespace);
+	args = get_next_arg(args, nextarg);
 
 	/*
 	 * offset, length are optional
@@ -788,7 +794,7 @@ static int unmap_seg(char *args)
 	if (!required_arg(args, "<seg-name>"))
 		return CMD_ERROR;
 	segname = strtok_r(args, whitespace, &nextarg);
-	args = nextarg + strspn(nextarg, whitespace);
+	args = get_next_arg(args, nextarg);
 
 	if (!segment_unmap(segname))
 		return CMD_ERROR;
@@ -812,7 +818,7 @@ static int map_seg(char *args)
 	if (!required_arg(args, "<seg-name>"))
 		return CMD_ERROR;
 	segname = strtok_r(args, whitespace, &nextarg);
-	args = nextarg + strspn(nextarg, whitespace);
+	args = get_next_arg(args, nextarg);
 
 	/*
 	 * offset, length are optional
@@ -856,7 +862,7 @@ static int mbind_seg(char *args)
 	if (!required_arg(args, "<seg-name>"))
 		return CMD_ERROR;
 	segname = strtok_r(args, whitespace, &nextarg);
-	args = nextarg + strspn(nextarg, whitespace);
+	args = get_next_arg(args, nextarg);
 
 	/*
 	 * offset, length are optional
@@ -871,7 +877,7 @@ static int mbind_seg(char *args)
 	if (policy < 0)
 		return CMD_ERROR;
 
-	args = nextarg + strspn(nextarg, whitespace);
+	args = get_next_arg(args, nextarg);
 	if (*args == '+') {
 		flags = get_mbind_flags(++args, &nextarg);
 		if (flags == -1)
@@ -914,7 +920,7 @@ static int shmem_seg(char *args)
 	if (!required_arg(args, "<seg-name>"))
 		return CMD_ERROR;
 	segname = strtok_r(args, whitespace, &nextarg);
-	args = nextarg + strspn(nextarg, whitespace);
+	args = get_next_arg(args, nextarg);
 
 	if (!required_arg(args, "<size>"))
 		return CMD_ERROR;
@@ -922,7 +928,7 @@ static int shmem_seg(char *args)
 	range.length = get_scaled_value(args, "size");
 	if (range.length == BOGUS_SIZE)
 		return CMD_ERROR;
-	args = nextarg + strspn(nextarg, whitespace);
+	args = get_next_arg(args, nextarg);
 
 	if (!segment_register(SEGT_SHM, segname, &range, MAP_SHARED))
 		return CMD_ERROR;
@@ -954,7 +960,7 @@ static int where_seg(char *args)
 	if (!required_arg(args, "<seg-name>"))
 		return CMD_ERROR;
 	segname = strtok_r(args, whitespace, &nextarg);
-	args = nextarg + strspn(nextarg, whitespace);
+	args = get_next_arg(args, nextarg);
 
 	/*
 	 * offset, length are optional
@@ -1107,7 +1113,6 @@ static int help_me(char *args)
 /*
  * =========================================================================
  */
-#define CMDBUFSZ 256
 
 static bool unique_abbrev(char *cmd, size_t clen, struct command *cmdp)
 {
-- 
2.28.0.236.gb10cc79966-goog

[LTP] [PATCH v2 1/3] hotplug/memory_hotplug: Handle NULL returned by strtok_r when parsing inputs

[Li Wang]

Hi Yuan,

Thanks for contributing to the memory-hotplug test. I have no objection to
these patches, but it seems quite a long time(since it imported to LTP from
Linux foundation at the year 2008) nobody actually touches this
memtoy except some code cleanup work.

I'm wondering whether you guys play with the memtoy regularly? and how do
you use it?

I take a rough look at the README file but got nothing useful to get
a start.

-- 
Regards,
Li Wang
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[LTP] [PATCH v2 1/3] hotplug/memory_hotplug: Handle NULL returned by strtok_r when parsing inputs

[Suren Baghdasaryan]

Hi Li,

On Thu, Aug 20, 2020 at 2:16 AM Li Wang <liwang@redhat.com> wrote:
>
> Hi Yuan,
>
> Thanks for contributing to the memory-hotplug test. I have no objection to these patches, but it seems quite a long time(since it imported to LTP from Linux foundation at the year 2008) nobody actually touches this memtoy except some code cleanup work.
>
> I'm wondering whether you guys play with the memtoy regularly? and how do you use it?

We did use memtoy to run memory experiments on Android (required some
minor tweaks to be able to build on Android). After Yuan's fixes we
were able to use it quite successfully.

>
> I take a rough look at the README file but got nothing useful to get a start.

You can see one of the scripts Yuan developed to ramp up memory
allocations of a given type (anon/file-backed/ion) using memtoy here:
https://android-review.googlesource.com/c/platform/external/ltp/+/1344879/44/testcases/kernel/hotplug/memory_hotplug/Scripts/ramp.sh
The usage is currently for experimentation only but we find it pretty
handy and we would like to keep using it in the future.
Thanks,
Suren.

>
> --
> Regards,
> Li Wang
>
> --
> To unsubscribe from this group and stop receiving emails from it, send an email to kernel-team+unsubscribe@android.com.

[LTP] [PATCH v2 1/3] hotplug/memory_hotplug: Handle NULL returned by strtok_r when parsing inputs

[Li Wang]

Hi Suren,

On Fri, Aug 21, 2020 at 7:41 AM Suren Baghdasaryan <surenb@google.com>
wrote:

> Hi Li,
>
> On Thu, Aug 20, 2020 at 2:16 AM Li Wang <liwang@redhat.com> wrote:
> >
> > Hi Yuan,
> >
> > Thanks for contributing to the memory-hotplug test. I have no objection
> to these patches, but it seems quite a long time(since it imported to LTP
> from Linux foundation at the year 2008) nobody actually touches this memtoy
> except some code cleanup work.
> >
> > I'm wondering whether you guys play with the memtoy regularly? and how
> do you use it?
>
> We did use memtoy to run memory experiments on Android (required some
> minor tweaks to be able to build on Android). After Yuan's fixes we
> were able to use it quite successfully.
>

Ok, I helped merge the patchset after testing. Thanks.


>
> >
> > I take a rough look at the README file but got nothing useful to get a
> start.
>
> You can see one of the scripts Yuan developed to ramp up memory
> allocations of a given type (anon/file-backed/ion) using memtoy here:
>
> https://android-review.googlesource.com/c/platform/external/ltp/+/1344879/44/testcases/kernel/hotplug/memory_hotplug/Scripts/ramp.sh
> The usage is currently for experimentation only but we find it pretty
> handy and we would like to keep using it in the future.
>

Yes, it also looks good to me. Maybe you can consider to upstreaming the
ramp.sh too.

-- 
Regards,
Li Wang
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[LTP] [PATCH v2 1/3] hotplug/memory_hotplug: Handle NULL returned by strtok_r when parsing inputs

[Suren Baghdasaryan]

On Sun, Aug 30, 2020 at 11:41 PM Li Wang <liwang@redhat.com> wrote:
>
> Hi Suren,
>
> On Fri, Aug 21, 2020 at 7:41 AM Suren Baghdasaryan <surenb@google.com> wrote:
>>
>> Hi Li,
>>
>> On Thu, Aug 20, 2020 at 2:16 AM Li Wang <liwang@redhat.com> wrote:
>> >
>> > Hi Yuan,
>> >
>> > Thanks for contributing to the memory-hotplug test. I have no objection to these patches, but it seems quite a long time(since it imported to LTP from Linux foundation at the year 2008) nobody actually touches this memtoy except some code cleanup work.
>> >
>> > I'm wondering whether you guys play with the memtoy regularly? and how do you use it?
>>
>> We did use memtoy to run memory experiments on Android (required some
>> minor tweaks to be able to build on Android). After Yuan's fixes we
>> were able to use it quite successfully.
>
>
> Ok, I helped merge the patchset after testing. Thanks.

Thanks a lot!

>
>>
>>
>> >
>> > I take a rough look at the README file but got nothing useful to get a start.
>>
>> You can see one of the scripts Yuan developed to ramp up memory
>> allocations of a given type (anon/file-backed/ion) using memtoy here:
>> https://android-review.googlesource.com/c/platform/external/ltp/+/1344879/44/testcases/kernel/hotplug/memory_hotplug/Scripts/ramp.sh
>> The usage is currently for experimentation only but we find it pretty
>> handy and we would like to keep using it in the future.
>
>
> Yes, it also looks good to me. Maybe you can consider to upstreaming the ramp.sh too.

Sounds good. We will definitely consider that.
Thanks,
Suren.

>
> --
> Regards,
> Li Wang