Exit on error when asking for value and reading stdin returns an error
(mainly if it has reached EOF or is closed).
This infinite loop happens in particular for hex/int configs without an
explicit default value.
Previously, this case would loop:
* oldconfig prompts for the value but stdin has reached EOF
* It gets the global default value : an empty string
* This is not a valid hex/int value so it prompts again, hence the
infinite loop.
This case happens with a configuration like this (a hex config without a
valid default value):
config TEST_KCONFIG
hex "Test KConfig"
# default 0x0
And using:
make oldconfig < /dev/null
This was discovered when working on Yocto bug[0] on a downstream
kconfig user (U-boot)
[0]: https://bugzilla.yoctoproject.org/show_bug.cgi?id=14136
Signed-off-by: Yoann Congal <[email protected]>
---
v2->v3:
* Simplify the patch by fusing comments of :
* Masahiro Yamada : Exit as soon as reading stdin hits an error
* Randy Dunlap : Display the name of the currently read symbol
v1->v2:
* Improve coding style
* Put more info in the commit message
scripts/kconfig/conf.c | 19 +++++++++++++++----
1 file changed, 15 insertions(+), 4 deletions(-)
diff --git a/scripts/kconfig/conf.c b/scripts/kconfig/conf.c
index 33d19e419908b..68f0c649a805e 100644
--- a/scripts/kconfig/conf.c
+++ b/scripts/kconfig/conf.c
@@ -74,13 +74,17 @@ static void strip(char *str)
}
/* Helper function to facilitate fgets() by Jean Sacren. */
-static void xfgets(char *str, int size, FILE *in)
+static int xfgets(char *str, int size, FILE *in)
{
+ int ret = 0;
+
if (!fgets(str, size, in))
- fprintf(stderr, "\nError in reading or end of file.\n");
+ ret = -1;
if (!tty_stdio)
printf("%s", str);
+
+ return ret;
}
static void set_randconfig_seed(void)
@@ -339,7 +343,10 @@ static int conf_askvalue(struct symbol *sym, const char *def)
/* fall through */
default:
fflush(stdout);
- xfgets(line, sizeof(line), stdin);
+ if (xfgets(line, sizeof(line), stdin) != 0) {
+ fprintf(stderr, "Error while reading value of symbol \"%s\"\n", sym->name);
+ exit(1);
+ }
break;
}
@@ -521,7 +528,11 @@ static int conf_choice(struct menu *menu)
/* fall through */
case oldaskconfig:
fflush(stdout);
- xfgets(line, sizeof(line), stdin);
+ if (xfgets(line, sizeof(line), stdin) != 0) {
+ fprintf(stderr, "Error while reading value of symbol \"%s\"\n",
+ sym->name);
+ exit(1);
+ }
strip(line);
if (line[0] == '?') {
print_help(menu);
--
2.30.2
Hi Yoann,
We encountered the same issue in U-Boot under Buildroot. I verified that
this patch fixes the issue, causing Kconfig to exit out instead of
infinitely looping. Thanks for the fix.
Tested-by: Brandon Maier <[email protected]>
On Tue, Sep 12, 2023 at 05:48:11PM +0200, Yoann Congal wrote:
> Exit on error when asking for value and reading stdin returns an error
> (mainly if it has reached EOF or is closed).
>
> This infinite loop happens in particular for hex/int configs without an
> explicit default value.
>
> Previously, this case would loop:
> * oldconfig prompts for the value but stdin has reached EOF
> * It gets the global default value : an empty string
> * This is not a valid hex/int value so it prompts again, hence the
> infinite loop.
>
> This case happens with a configuration like this (a hex config without a
> valid default value):
> config TEST_KCONFIG
> hex "Test KConfig"
> # default 0x0
>
> And using:
> make oldconfig < /dev/null
>
> This was discovered when working on Yocto bug[0] on a downstream
> kconfig user (U-boot)
>
> [0]: https://bugzilla.yoctoproject.org/show_bug.cgi?id=14136
>
> Signed-off-by: Yoann Congal <[email protected]>
> ---
> v2->v3:
> * Simplify the patch by fusing comments of :
> * Masahiro Yamada : Exit as soon as reading stdin hits an error
> * Randy Dunlap : Display the name of the currently read symbol
>
> v1->v2:
> * Improve coding style
> * Put more info in the commit message
>
> scripts/kconfig/conf.c | 19 +++++++++++++++----
> 1 file changed, 15 insertions(+), 4 deletions(-)
>
> diff --git a/scripts/kconfig/conf.c b/scripts/kconfig/conf.c
> index 33d19e419908b..68f0c649a805e 100644
> --- a/scripts/kconfig/conf.c
> +++ b/scripts/kconfig/conf.c
> @@ -74,13 +74,17 @@ static void strip(char *str)
> }
>
> /* Helper function to facilitate fgets() by Jean Sacren. */
> -static void xfgets(char *str, int size, FILE *in)
> +static int xfgets(char *str, int size, FILE *in)
> {
> + int ret = 0;
> +
> if (!fgets(str, size, in))
> - fprintf(stderr, "\nError in reading or end of file.\n");
> + ret = -1;
>
> if (!tty_stdio)
> printf("%s", str);
> +
> + return ret;
> }
>
> static void set_randconfig_seed(void)
> @@ -339,7 +343,10 @@ static int conf_askvalue(struct symbol *sym, const char *def)
> /* fall through */
> default:
> fflush(stdout);
> - xfgets(line, sizeof(line), stdin);
> + if (xfgets(line, sizeof(line), stdin) != 0) {
> + fprintf(stderr, "Error while reading value of symbol \"%s\"\n", sym->name);
> + exit(1);
> + }
> break;
> }
>
> @@ -521,7 +528,11 @@ static int conf_choice(struct menu *menu)
> /* fall through */
> case oldaskconfig:
> fflush(stdout);
> - xfgets(line, sizeof(line), stdin);
> + if (xfgets(line, sizeof(line), stdin) != 0) {
> + fprintf(stderr, "Error while reading value of symbol \"%s\"\n",
> + sym->name);
> + exit(1);
> + }
> strip(line);
> if (line[0] == '?') {
> print_help(menu);
> --
> 2.30.2
>
On 10/4/23 23:52, Brandon Maier wrote:
> Hi Yoann,
Hi,
> We encountered the same issue in U-Boot under Buildroot. I verified that
> this patch fixes the issue, causing Kconfig to exit out instead of
> infinitely looping. Thanks for the fix.
Awesome! I've also found this on U-boot (but under Yocto).
I planned to get this merged here in kbuild then U-boot downstream and then Yocto.
Please CC me if you try to do something with this patch in Buildroot :)
> Tested-by: Brandon Maier <[email protected]>
Thanks!
> On Tue, Sep 12, 2023 at 05:48:11PM +0200, Yoann Congal wrote:
>> Exit on error when asking for value and reading stdin returns an error
>> (mainly if it has reached EOF or is closed).
>>
>> This infinite loop happens in particular for hex/int configs without an
>> explicit default value.
>>
>> Previously, this case would loop:
>> * oldconfig prompts for the value but stdin has reached EOF
>> * It gets the global default value : an empty string
>> * This is not a valid hex/int value so it prompts again, hence the
>> infinite loop.
>>
>> This case happens with a configuration like this (a hex config without a
>> valid default value):
>> config TEST_KCONFIG
>> hex "Test KConfig"
>> # default 0x0
>>
>> And using:
>> make oldconfig < /dev/null
>>
>> This was discovered when working on Yocto bug[0] on a downstream
>> kconfig user (U-boot)
>>
>> [0]: https://bugzilla.yoctoproject.org/show_bug.cgi?id=14136
>>
>> Signed-off-by: Yoann Congal <[email protected]>
>> ---
>> v2->v3:
>> * Simplify the patch by fusing comments of :
>> * Masahiro Yamada : Exit as soon as reading stdin hits an error
>> * Randy Dunlap : Display the name of the currently read symbol
>>
>> v1->v2:
>> * Improve coding style
>> * Put more info in the commit message
>>
>> scripts/kconfig/conf.c | 19 +++++++++++++++----
>> 1 file changed, 15 insertions(+), 4 deletions(-)
>>
>> diff --git a/scripts/kconfig/conf.c b/scripts/kconfig/conf.c
>> index 33d19e419908b..68f0c649a805e 100644
>> --- a/scripts/kconfig/conf.c
>> +++ b/scripts/kconfig/conf.c
>> @@ -74,13 +74,17 @@ static void strip(char *str)
>> }
>>
>> /* Helper function to facilitate fgets() by Jean Sacren. */
>> -static void xfgets(char *str, int size, FILE *in)
>> +static int xfgets(char *str, int size, FILE *in)
>> {
>> + int ret = 0;
>> +
>> if (!fgets(str, size, in))
>> - fprintf(stderr, "\nError in reading or end of file.\n");
>> + ret = -1;
>>
>> if (!tty_stdio)
>> printf("%s", str);
>> +
>> + return ret;
>> }
>>
>> static void set_randconfig_seed(void)
>> @@ -339,7 +343,10 @@ static int conf_askvalue(struct symbol *sym, const char *def)
>> /* fall through */
>> default:
>> fflush(stdout);
>> - xfgets(line, sizeof(line), stdin);
>> + if (xfgets(line, sizeof(line), stdin) != 0) {
>> + fprintf(stderr, "Error while reading value of symbol \"%s\"\n", sym->name);
>> + exit(1);
>> + }
>> break;
>> }
>>
>> @@ -521,7 +528,11 @@ static int conf_choice(struct menu *menu)
>> /* fall through */
>> case oldaskconfig:
>> fflush(stdout);
>> - xfgets(line, sizeof(line), stdin);
>> + if (xfgets(line, sizeof(line), stdin) != 0) {
>> + fprintf(stderr, "Error while reading value of symbol \"%s\"\n",
>> + sym->name);
>> + exit(1);
>> + }
>> strip(line);
>> if (line[0] == '?') {
>> print_help(menu);
>> --
>> 2.30.2
>>
--
Yoann Congal
Smile ECS - Tech Expert