Revert "posix: add stubs for signal.h functions that need process support"

This reverts commit b2243af.

PR zephyrproject-rtos#73978 introduced a regression.
Unfortunately this PR cannot be reverted without reverting also
Let's revert both PRs to stabilize main again towards the 3.7 release.

For more details on the issue see
zephyrproject-rtos#75205

(cherry picked from commit 772ba46)

Original-Signed-off-by: Alberto Escolar Piedras <[email protected]>
GitOrigin-RevId: 772ba46
Change-Id: I138b76bf5d9ce465010830a966cdd7636f61ad26
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/zephyr/+/5678571
Tested-by: ChromeOS Prod (Robot) <[email protected]>
Commit-Queue: Fabio Baltieri <[email protected]>
Reviewed-by: Fabio Baltieri <[email protected]>

Author: aescolar

include/zephyr/posix/signal.h

@@ -77,16 +77,6 @@ typedef struct {
 #define SIG_UNBLOCK 2
 #endif
 
-#define SIG_DFL ((void *)0)
-#define SIG_IGN ((void *)1)
-#define SIG_ERR ((void *)-1)
-
-#define SI_USER 1
-#define SI_QUEUE 2
-#define SI_TIMER 3
-#define SI_ASYNCIO 4
-#define SI_MESGQ 5
-
 typedef int	sig_atomic_t;		/* Atomic entity type (ANSI) */
 
 union sigval {
@@ -102,34 +92,12 @@ struct sigevent {
 	int sigev_signo;
 };
 
-typedef struct {
-	int si_signo;
-	int si_code;
-	union sigval si_value;
-} siginfo_t;
-
-struct sigaction {
-	void (*sa_handler)(int signno);
-	sigset_t sa_mask;
-	int sa_flags;
-	void (*sa_sigaction)(int signo, siginfo_t *info, void *context);
-};
-
-unsigned int alarm(unsigned int seconds);
-int kill(pid_t pid, int sig);
-int pause(void);
-int raise(int signo);
-int sigaction(int sig, const struct sigaction *ZRESTRICT act, struct sigaction *ZRESTRICT oact);
-int sigpending(sigset_t *set);
-int sigsuspend(const sigset_t *sigmask);
-int sigwait(const sigset_t *ZRESTRICT set, int *ZRESTRICT signo);
 char *strsignal(int signum);
 int sigemptyset(sigset_t *set);
 int sigfillset(sigset_t *set);
 int sigaddset(sigset_t *set, int signo);
 int sigdelset(sigset_t *set, int signo);
 int sigismember(const sigset_t *set, int signo);
-void (*signal(int signo, void (*)(int signo)))(int signo);
 int sigprocmask(int how, const sigset_t *ZRESTRICT set, sigset_t *ZRESTRICT oset);
 
 int pthread_sigmask(int how, const sigset_t *ZRESTRICT set, sigset_t *ZRESTRICT oset);

lib/libc/Kconfig

@@ -105,7 +105,6 @@ config NEWLIB_LIBC
 	imply POSIX_FD_MGMT_ALIAS_LSEEK
 	imply POSIX_FILE_SYSTEM_ALIAS_FSTAT
 	imply POSIX_MULTI_PROCESS_ALIAS_GETPID
-	imply POSIX_SIGNALS_ALIAS_KILL
 	help
 	  Build with newlib library. The newlib library is expected to be
 	  part of the SDK in this case.

lib/posix/options/Kconfig.signal

@@ -24,7 +24,6 @@ endif # POSIX_REALTIME_SIGNALS
 config POSIX_SIGNALS
 	bool "POSIX signals [EXPERIMENTAL]"
 	select EXPERIMENTAL
-	select POSIX_MULTI_PROCESS
 	help
 	  Enable support for POSIX signals.
 
@@ -37,12 +36,6 @@ config POSIX_SIGNAL_STRING_DESC
 	  Use full description for the strsignal API.
 	  Will use 256 bytes of ROM.
 
-# These options are intended to be used for compatibility with external POSIX
-# implementations such as those in Newlib or Picolibc.
-
-config POSIX_SIGNALS_ALIAS_KILL
-	bool
-
 endif
 
 endmenu # "Signal support"

lib/posix/options/signal.c

@@ -118,62 +118,3 @@ int sigprocmask(int how, const sigset_t *ZRESTRICT set, sigset_t *ZRESTRICT oset
 	errno = ENOSYS;
 	return -1;
 }
-
-/*
- * The functions below are provided so that conformant POSIX applications and libraries can still
- * link.
- */
-
-unsigned int alarm(unsigned int seconds)
-{
-	ARG_UNUSED(seconds);
-	return 0;
-}
-
-int kill(pid_t pid, int sig)
-{
-	ARG_UNUSED(pid);
-	ARG_UNUSED(sig);
-	errno = ENOSYS;
-	return -1;
-}
-#ifdef CONFIG_POSIX_SIGNALS_ALIAS_KILL
-FUNC_ALIAS(kill, _kill, int);
-#endif /* CONFIG_POSIX_SIGNALS_ALIAS_KILL */
-
-int pause(void)
-{
-	errno = ENOSYS;
-	return -1;
-}
-
-int sigaction(int sig, const struct sigaction *ZRESTRICT act, struct sigaction *ZRESTRICT oact)
-{
-	ARG_UNUSED(sig);
-	ARG_UNUSED(act);
-	ARG_UNUSED(oact);
-	errno = ENOSYS;
-	return -1;
-}
-
-int sigpending(sigset_t *set)
-{
-	ARG_UNUSED(set);
-	errno = ENOSYS;
-	return -1;
-}
-
-int sigsuspend(const sigset_t *sigmask)
-{
-	ARG_UNUSED(sigmask);
-	errno = ENOSYS;
-	return -1;
-}
-
-int sigwait(const sigset_t *ZRESTRICT set, int *ZRESTRICT sig)
-{
-	ARG_UNUSED(set);
-	ARG_UNUSED(sig);
-	errno = ENOSYS;
-	return -1;
-}