[PATCH] awk: fix printf %%

[Denys Vlasenko]

Applied, thank you.

On Thu, Sep 2, 2021 at 1:43 PM Daniel Thau <danthau at bedrocklinux.org> wrote:
>
> A refactor of the awk printf code in
> e2e3802987266c98df0efdf40ad5da4b07df0113
> appears to have broken the printf interpretation of two percent signs,
> which normally outputs only one percent sign.
>
> The patch below brings busybox awk printf behavior back into alignment
> with the pre-e2e380 behavior, the busybox printf util, and other common
> (awk and non-awk) printf implementations.
>
> Please let me know if there's anything else I can or should do ensure
> the awk printf %% handling is remedied.
>
> Thanks!
>
> Signed-off-by: Daniel "paradigm" Thau <danthau at bedrocklinux.org>
> ---
>  editors/awk.c          | 9 ++++++++-
>  testsuite/awk.tests    | 6 ++++++
>  testsuite/printf.tests | 5 +++++
>  3 files changed, 19 insertions(+), 1 deletion(-)
>
> diff --git a/editors/awk.c b/editors/awk.c
> index 3adbca7aa..162000697 100644
> --- a/editors/awk.c
> +++ b/editors/awk.c
> @@ -2346,8 +2346,15 @@ static char *awk_printf(node *n, size_t *len)
>                 size_t slen;
>
>                 s = f;
> -               while (*f && (*f != '%' || *++f == '%'))
> +               while (*f && *f != '%')
>                         f++;
> +               if (*++f == '%') { /* double % */
> +                       *f = '\0';
> +                       s = xstrdup(s);
> +                       slen = strlen(s);
> +                       *f++ = c = '%';
> +                       goto tail;
> +               }
>                 while (*f && !isalpha(*f)) {
>                         if (*f == '*')
>                                 syntax_error("%*x formats are not supported");
> diff --git a/testsuite/awk.tests b/testsuite/awk.tests
> index dc2ae2e11..bcaafe8fd 100755
> --- a/testsuite/awk.tests
> +++ b/testsuite/awk.tests
> @@ -463,4 +463,10 @@ testing "awk \"cmd\" | getline" \
>         "HELLO\n" \
>         '' ''
>
> +# printf %% should print one % (had a bug where it didn't)
> +testing 'awk printf %% prints one %' \
> +       "awk 'BEGIN { printf \"%%\n\" }'" \
> +       "%\n" \
> +       '' ''
> +
>  exit $FAILCOUNT
> diff --git a/testsuite/printf.tests b/testsuite/printf.tests
> index 34a65926e..050edef71 100755
> --- a/testsuite/printf.tests
> +++ b/testsuite/printf.tests
> @@ -79,6 +79,11 @@ testing "printf understands %Ld" \
>         "-5\n""0\n" \
>         "" ""
>
> +testing "printf understands %%" \
> +       "${bb}printf '%%\n' 2>&1; echo \$?" \
> +       "%\n""0\n" \
> +       "" ""
> +
>  testing "printf handles positive numbers for %d" \
>         "${bb}printf '%d\n' 3 +3 '   3' '   +3' 2>&1; echo \$?" \
>         "3\n"\
> --
> 2.20.1
>
>
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