Applied, thanks!
On Wed, Sep 12, 2018 at 5:39 PM Rasmus Villemoes
<[email protected]> wrote:
>
> When an application documents that it responds such and such to
> SIGRTMIN+n, that almost always means with respect to the libc-provided
> SIGRTMIN. Hence I disagree with the "more correct" in commit
> 7b276fc17594. In any case, this is rather unfortunate:
>
> # kill -l RTMIN+2
> 36
> # busybox kill -l RTMIN+2
> 34
>
> (the first shell is bash). We probably can't change default behaviour
> after 7 years, but at least we can provide a config option.
>
> We avoid a little code generation (repeated calls to
> __libc_current_sigrtmin) by stashing SIGRTMIN/SIGRTMAX in local
> variables, but it does cost ~50 bytes. The next patch serves as penance
> for that.
>
> Signed-off-by: Rasmus Villemoes <[email protected]>
> ---
> libbb/u_signal_names.c | 49 ++++++++++++++++++++++++++++++++++++-------------
> 1 file changed, 36 insertions(+), 13 deletions(-)
>
> diff --git a/libbb/u_signal_names.c b/libbb/u_signal_names.c
> index b3038e32d..5ef5c3f28 100644
> --- a/libbb/u_signal_names.c
> +++ b/libbb/u_signal_names.c
> @@ -12,6 +12,15 @@
> //config: help
> //config: Support RTMIN[+n] and RTMAX[-n] signal names
> //config: in kill, killall etc. This costs ~250 bytes.
> +//config:config FEATURE_RTMINMAX_USE_LIBC_DEFINITIONS
> +//config: bool "Use the definitions of SIGRTMIN/SIGRTMAX provided by
> libc"
> +//config: depends on FEATURE_RTMINMAX
> +//config: help
> +//config: Some C libraries reserve a few real-time signals for internal
> +//config: use, and adjust the values of SIGRTMIN/SIGRTMAX seen by
> +//config: applications accordingly. Saying yes here means that a signal
> +//config: name RTMIN+n will be interpreted according to the libc
> definition
> +//config: of SIGRTMIN, and not the raw definition provided by the
> kernel.
>
> #include "libbb.h"
>
> @@ -123,7 +132,7 @@ static const char signals[][7] ALIGN1 = {
> #ifdef SIGSYS
> [SIGSYS ] = "SYS",
> #endif
> -#if ENABLE_FEATURE_RTMINMAX
> +#if ENABLE_FEATURE_RTMINMAX && !ENABLE_FEATURE_RTMINMAX_USE_LIBC_DEFINITIONS
> # ifdef __SIGRTMIN
> [__SIGRTMIN] = "RTMIN",
> # endif
> @@ -140,6 +149,7 @@ static const char signals[][7] ALIGN1 = {
> int FAST_FUNC get_signum(const char *name)
> {
> unsigned i;
> + unsigned sigrtmin, sigrtmax;
>
> i = bb_strtou(name, NULL, 10);
> if (!errno && i < NSIG) /* for shells, we allow 0 too */
> @@ -168,10 +178,13 @@ int FAST_FUNC get_signum(const char *name)
> # endif
> #endif
>
> -#if ENABLE_FEATURE_RTMINMAX
> -# if defined(SIGRTMIN) && defined(SIGRTMAX)
> -/* libc may use some rt sigs for pthreads and therefore "remap" SIGRTMIN/MAX,
> - * but we want to use "raw" SIGRTMIN/MAX. Underscored names, if exist,
> provide
> +#if ENABLE_FEATURE_RTMINMAX && defined(SIGRTMIN) && defined(SIGRTMAX)
> +# if ENABLE_FEATURE_RTMINMAX_USE_LIBC_DEFINITIONS
> +/* Use the libc provided values. */
> + sigrtmin = SIGRTMIN;
> + sigrtmax = SIGRTMAX;
> +# else
> +/* Use the "raw SIGRTMIN/MAX. Underscored names, if exist, provide
> * them. If they don't exist, fall back to non-underscored ones: */
> # if !defined(__SIGRTMIN)
> # define __SIGRTMIN SIGRTMIN
> @@ -179,25 +192,27 @@ int FAST_FUNC get_signum(const char *name)
> # if !defined(__SIGRTMAX)
> # define __SIGRTMAX SIGRTMAX
> # endif
> + sigrtmin = __SIGRTMIN;
> + sigrtmax = __SIGRTMAX;
> +# endif
> if (strncasecmp(name, "RTMIN", 5) == 0) {
> if (!name[5])
> - return __SIGRTMIN;
> + return sigrtmin;
> if (name[5] == '+') {
> i = bb_strtou(name + 6, NULL, 10);
> - if (!errno && i <= __SIGRTMAX - __SIGRTMIN)
> - return __SIGRTMIN + i;
> + if (!errno && i <= sigrtmax - sigrtmin)
> + return sigrtmin + i;
> }
> }
> else if (strncasecmp(name, "RTMAX", 5) == 0) {
> if (!name[5])
> - return __SIGRTMAX;
> + return sigrtmax;
> if (name[5] == '-') {
> i = bb_strtou(name + 6, NULL, 10);
> - if (!errno && i <= __SIGRTMAX - __SIGRTMIN)
> - return __SIGRTMAX - i;
> + if (!errno && i <= sigrtmax - sigrtmin)
> + return sigrtmax - i;
> }
> }
> -# endif
> #endif
>
> return -1;
> @@ -228,8 +243,16 @@ void FAST_FUNC print_signames(void)
> printf("%2u) %s\n", signo, name);
> }
> #if ENABLE_FEATURE_RTMINMAX
> -# ifdef __SIGRTMAX
> +# if ENABLE_FEATURE_RTMINMAX_USE_LIBC_DEFINITIONS
> +# if defined(SIGRTMIN) && defined(SIGRTMAX)
> + printf("%2u) %s\n", SIGRTMIN, "RTMIN");
> + printf("%2u) %s\n", SIGRTMAX, "RTMAX");
> +# endif
> +# else
> +// __SIGRTMIN is included in signals[] array.
> +# ifdef __SIGRTMAX
> printf("%2u) %s\n", __SIGRTMAX, "RTMAX");
> +# endif
> # endif
> #endif
> }
> --
> 2.16.4
>
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