* [PATCH RFC] common: env: handle var="" not as var=NULL
@ 2016-06-13 10:51 Alexander Aring
2016-06-14 6:25 ` Sascha Hauer
0 siblings, 1 reply; 2+ messages in thread
From: Alexander Aring @ 2016-06-13 10:51 UTC (permalink / raw)
To: barebox; +Cc: Alexander Aring
This patch changes the behaviour which I think is used everywhere in
barebox code. Currently var="" and var=NULL will end in the same
behaviour.
New behaviour is:
setenv(name, "") -> sets name to ""
\-> getenv(name) -> ""
setenv(name, NULL) -> deletes env
\-> getenv(name) -> NULL
It seems that barebox code already wants such behaviour, by run
$ grep -r "\"\"" | grep setenv
it finds most all related code sections which use "".
I detected the issue while commenting #ip="foo" in my env. The code
part:
net/ifup.c: setenv("ip", "");
Sets at first "ip" to "" but will end in the old behaviour as "delete".
The getenv("ip") in ifup.c will not check on the NULL value and has a
general handling for unknown ip env.
Note:
Also check commit e7ed69d5 ("setenv: be robust against setenv(<var>,
NULL") which says that hush will handle "" and NULL as the same.
Another check would be:
$ grep -r "NULL" | grep setenv
which should show the behaviour in case of deleting env.
Signed-off-by: Alexander Aring <aar@pengutronix.de>
---
I test the ip env stuff only that barebox will not crash anymore but I
think it will break some other setenv/getenv behaviour.
The question is "Shall we keep that "" and NULL ends in same behaviour"
and fix the code which use it wrong, e.g. setenv("ip", ""); getenv("ip").
common/env.c | 4 ----
1 file changed, 4 deletions(-)
diff --git a/common/env.c b/common/env.c
index 6f736d5..4d8d446 100644
--- a/common/env.c
+++ b/common/env.c
@@ -210,10 +210,6 @@ int setenv(const char *_name, const char *value)
int ret = 0;
struct list_head *list;
- if (value && !*value)
- value = NULL;
-
-
if ((par = strchr(name, '.'))) {
struct device_d *dev;
--
2.8.3
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^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [PATCH RFC] common: env: handle var="" not as var=NULL
2016-06-13 10:51 [PATCH RFC] common: env: handle var="" not as var=NULL Alexander Aring
@ 2016-06-14 6:25 ` Sascha Hauer
0 siblings, 0 replies; 2+ messages in thread
From: Sascha Hauer @ 2016-06-14 6:25 UTC (permalink / raw)
To: Alexander Aring; +Cc: barebox
On Mon, Jun 13, 2016 at 12:51:52PM +0200, Alexander Aring wrote:
> This patch changes the behaviour which I think is used everywhere in
> barebox code. Currently var="" and var=NULL will end in the same
> behaviour.
>
> New behaviour is:
>
> setenv(name, "") -> sets name to ""
> \-> getenv(name) -> ""
>
> setenv(name, NULL) -> deletes env
> \-> getenv(name) -> NULL
>
> It seems that barebox code already wants such behaviour, by run
>
> $ grep -r "\"\"" | grep setenv
>
> it finds most all related code sections which use "".
>
> I detected the issue while commenting #ip="foo" in my env. The code
> part:
>
> net/ifup.c: setenv("ip", "");
>
> Sets at first "ip" to "" but will end in the old behaviour as "delete".
> The getenv("ip") in ifup.c will not check on the NULL value and has a
> general handling for unknown ip env.
>
> Note:
> Also check commit e7ed69d5 ("setenv: be robust against setenv(<var>,
> NULL") which says that hush will handle "" and NULL as the same.
>
> Another check would be:
>
> $ grep -r "NULL" | grep setenv
>
> which should show the behaviour in case of deleting env.
>
> Signed-off-by: Alexander Aring <aar@pengutronix.de>
> ---
> I test the ip env stuff only that barebox will not crash anymore but I
> think it will break some other setenv/getenv behaviour.
>
> The question is "Shall we keep that "" and NULL ends in same behaviour"
> and fix the code which use it wrong, e.g. setenv("ip", ""); getenv("ip").
I'm not sure at the moment if a var="" should delete a variable or just
set it to an empty string. In any case we should fix net/ifup.c.
getenv() can return NULL and the code should be prepared for that.
Sascha
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