[musl] [PATCH v2 3/3] signal: add str2sig(3) from POSIX.1-2024

[contact@hacktivis.me]

From: "Haelwenn (lanodan) Monnier" <contact@hacktivis.me>

---
 include/signal.h     |  1 +
 src/signal/str2sig.c | 45 ++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 46 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..b6a4fc23
--- /dev/null
+++ b/src/signal/str2sig.c
@@ -0,0 +1,45 @@
+#include <signal.h>
+#include <string.h>
+#include <errno.h>
+#include <stdlib.h>
+
+int str2sig(const char *restrict str, int *restrict pnum)
+{
+	if (str[0] == '\0') return -1;
+
+	errno = 0;
+	long signum = strtol(str, NULL, 10);
+	if (errno == 0 && signum < _NSIG) return (*pnum = signum, 0);
+
+	if (strnlen(str, sizeof *__sys_signame) <= sizeof *__sys_signame)
+		for (int i = 0; i < sizeof __sys_signame/sizeof *__sys_signame; i++)
+			if (strncmp(str, __sys_signame[i], sizeof *__sys_signame) == 0)
+				return (*pnum = i, 0);
+
+	// signal aliases
+	if (strcmp(str, "IOT") == 0)
+		return (*pnum = SIGIOT, 0);
+	if (strcmp(str, "UNUSED") == 0)
+		return (*pnum = SIGUNUSED, 0);
+#if SIGPOLL != SIGIO
+	if (strcmp(str, "POLL") == 0)
+		return (*pnum = SIGPOLL, 0);
+#endif
+
+	if (strcmp(str, "RTMIN") == 0)
+		return (*pnum = SIGRTMIN, 0);
+	if (strcmp(str, "RTMAX") == 0)
+		return (*pnum = SIGRTMAX, 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;
+	}
+
+	return -1;
+}
-- 
2.44.2