Re: [musl] [PATCH 2/2] signal: add str2sig(3) from POSIX.1-2024

[Pedro Falcato <pedro.falcato@gmail.com>]

On Sun, Aug 4, 2024 at 1:42 PM <contact@hacktivis.me> wrote:
>
> From: "Haelwenn (lanodan) Monnier" <contact@hacktivis.me>
>
> ---
>  include/signal.h     |  1 +
>  src/signal/str2sig.c | 72 ++++++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 73 insertions(+)
>  create mode 100644 src/signal/str2sig.c
>
> diff --git a/include/signal.h b/include/signal.h
> index 217cfa08..fd486cd0 100644
> --- a/include/signal.h
> +++ b/include/signal.h
> @@ -235,6 +235,7 @@ void psignal(int, const char *);
>
>  #define SIG2STR_MAX sizeof("RTMIN+32")
>  int sig2str(int signum, char *str);
> +int str2sig(const char *restrict str, int *restrict pnum);
>
>  #endif
>
> diff --git a/src/signal/str2sig.c b/src/signal/str2sig.c
> new file mode 100644
> index 00000000..6da2d4f4
> --- /dev/null
> +++ b/src/signal/str2sig.c
> @@ -0,0 +1,72 @@
> +#include <signal.h>
> +#include <string.h>
> +#include <errno.h>
> +#include <stdlib.h>
> +
> +int str2sig(const char *restrict str, int *restrict pnum)
> +{
> +       errno = 0;
> +       long signum = strtol(str, NULL, 10);
> +       if(errno == 0 && signum < _NSIG)
> +       {
> +               *pnum = signum;
> +               return 0;
> +       }
> +
> +       if (
> +               strncmp(str, "RTMIN+", 6) == 0
> +               || strncmp(str, "RTMAX-", 6) == 0
> +       )
> +       {
> +               errno = 0;
> +               long sigrt = strtol(str+6, NULL, 10);
> +               if(errno != 0 || sigrt < 1 || sigrt > SIGRTMAX - SIGRTMIN) return -1;
> +
> +               *pnum = str[5] == '+' ? SIGRTMIN + sigrt : SIGRTMAX - sigrt;
> +               return 0;
> +       }
> +
> +       int ret = -1;
> +       if(strcmp(str, "HUP") == 0) ret = SIGHUP;
> +       if(strcmp(str, "INT") == 0) ret = SIGINT;
> +       if(strcmp(str, "QUIT") == 0) ret = SIGQUIT;
> +       if(strcmp(str, "ILL") == 0) ret = SIGILL;
> +       if(strcmp(str, "TRAP") == 0) ret = SIGTRAP;
> +       if(strcmp(str, "ABRT") == 0) ret = SIGABRT;
> +       if(strcmp(str, "IOT") == 0) ret = SIGIOT;
> +       if(strcmp(str, "BUS") == 0) ret = SIGBUS;
> +       if(strcmp(str, "FPE") == 0) ret = SIGFPE;
> +       if(strcmp(str, "KILL") == 0) ret = SIGKILL;
> +       if(strcmp(str, "USR1") == 0) ret = SIGUSR1;
> +       if(strcmp(str, "SEGV") == 0) ret = SIGSEGV;
> +       if(strcmp(str, "USR2") == 0) ret = SIGUSR2;
> +       if(strcmp(str, "PIPE") == 0) ret = SIGPIPE;
> +       if(strcmp(str, "ALRM") == 0) ret = SIGALRM;
> +       if(strcmp(str, "TERM") == 0) ret = SIGTERM;
> +       if(strcmp(str, "STKFLT") == 0) ret = SIGSTKFLT;
> +       if(strcmp(str, "CHLD") == 0) ret = SIGCHLD;
> +       if(strcmp(str, "CONT") == 0) ret = SIGCONT;
> +       if(strcmp(str, "STOP") == 0) ret = SIGSTOP;
> +       if(strcmp(str, "TSTP") == 0) ret = SIGTSTP;
> +       if(strcmp(str, "TTIN") == 0) ret = SIGTTIN;
> +       if(strcmp(str, "TTOU") == 0) ret = SIGTTOU;
> +       if(strcmp(str, "URG") == 0) ret = SIGURG;
> +       if(strcmp(str, "XCPU") == 0) ret = SIGXCPU;
> +       if(strcmp(str, "XFSZ") == 0) ret = SIGXFSZ;
> +       if(strcmp(str, "VTALRM") == 0) ret = SIGVTALRM;
> +       if(strcmp(str, "PROF") == 0) ret = SIGPROF;
> +       if(strcmp(str, "WINCH") == 0) ret = SIGWINCH;
> +       if(strcmp(str, "IO") == 0) ret = SIGIO;
> +       if(strcmp(str, "POLL") == 0) ret = SIGPOLL;
> +       if(strcmp(str, "PWR") == 0) ret = SIGPWR;
> +       if(strcmp(str, "SYS") == 0) ret = SIGSYS;
> +       if(strcmp(str, "UNUSED") == 0) ret = SIGUNUSED;
> +
> +       if(strcmp(str, "RTMIN") == 0) ret = SIGRTMIN;
> +       if(strcmp(str, "RTMAX") == 0) ret = SIGRTMAX;

To me it looks like the best way to implement these two functions is
to create a table of some sorts (indexed by signal, so array[SIGINT] =
"INT") and then use it.
str2sig would just iterate the whole array with strcmps, which is a
_little_ slow but this is probably not performance critical anyway.

Special casing would be required for RT signals, but that's no biggie.
What do you think?

--
Pedro