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]>
Tested-by: Brandon Maier <[email protected]>
---
v3->v4:
* Added Brandon Maier's "Tested-by". Thanks!
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 33d19e419908..68f0c649a805 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 Tue, Oct 31, 2023 at 8:17 PM Yoann Congal <[email protected]> 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]>
> Tested-by: Brandon Maier <[email protected]>
> ---
> v3->v4:
> * Added Brandon Maier's "Tested-by". Thanks!
> 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 33d19e419908..68f0c649a805 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;
> }
This is not what I suggested.
I suggested much simpler code:
https://lore.kernel.org/linux-kbuild/CAK7LNAS8a=8n9r7kQrLTPpKwqXG1d1sd0WjJ8PQhOXHXxnSyNQ@mail.gmail.com/
It is easy to know the symbol name that is causing the issue;
it was shown in the prompt just before the failure.
Also, please note that the 'x' prefix is often used
for functions that do not require error check.
(e.g. xmalloc)
>
> 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
>
--
Best Regards
Masahiro Yamada