Add build system scaffolding and libc headers

1 files changed, 52 insertions, 0 deletions

diff --git a/lib/libc/signal/str2sig.c b/lib/libc/signal/str2sig.c
new file mode 100644
index 00000000..288948d7
--- /dev/null
+++ b/lib/libc/signal/str2sig.c
@@ -0,0 +1,52 @@
+#include <__signal.h>
+#include <errno.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdbool.h>
+#include <asm-generic/signal.h>
+
+int str2sig(const char *restrict str, int *restrict pnum)
+{
+	for (size_t i = SIGHUP; i <= SIGSYS; ++i) {
+		if (!strcmp(str, __sys_signame[i])) {
+			*pnum = i;
+			return 0;
+		}
+	}
+
+	if (strcmp(str, "RTMIN") == 0) {
+		*pnum = SIGRTMIN;
+		return 0;
+	}
+
+	if (strcmp(str, "RTMAX") == 0) {
+		*pnum = SIGRTMAX;
+		return 0;
+	}
+
+	int base = 0;
+	if (strncmp(str, "RTMIN+", 6) == 0) {
+		base = SIGRTMIN;
+		str += 5;
+	} else if (strncmp(str, "RTMAX-", 6) == 0) {
+		base = SIGRTMAX;
+		str += 5;
+	}
+
+	char *end = NULL;
+	errno = 0;
+	int offset = strtol(str, &end, 10);
+	if (errno || *end) {
+		return -1;
+	}
+
+	int result = base + offset;
+	bool regular = (base == 0 && result >= SIGHUP && result <= SIGSYS);
+	bool realtime = (result >= SIGRTMIN && result <= SIGRTMAX);
+	if (!regular && !realtime) {
+		return -1;
+	}
+
+	*pnum = result;
+	return 0;
+}