Fix handling of real-time signals.

lib/util/sig2str.c

@@ -62,9 +62,22 @@ int
 sudo_sig2str(int signo, char *signame)
 {
 #if defined(SIGRTMIN) && defined(SIGRTMAX)
-    /* Realtime signal support as per Solaris. */
+    /* Realtime signal support. */
     if (signo >= SIGRTMIN && signo <= SIGRTMAX) {
-	(void)snprintf(signame, SIG2STR_MAX, "RTMIN+%d", (signo - SIGRTMIN));
+	const long rtmax = sysconf(_SC_RTSIG_MAX);
+	if (rtmax > 0) {
+	    if (signo == SIGRTMIN) {
+		strlcpy(signame, "RTMIN", SIG2STR_MAX);
+	    } else if (signo == SIGRTMAX) {
+		strlcpy(signame, "RTMAX", SIG2STR_MAX);
+	    } else if (signo <= SIGRTMIN + (rtmax / 2) - 1) {
+		(void)snprintf(signame, SIG2STR_MAX, "RTMIN+%d",
+		    (signo - SIGRTMIN));
+	    } else {
+		(void)snprintf(signame, SIG2STR_MAX, "RTMAX-%d",
+		    (SIGRTMAX - signo));
+	    }
+	}
 	return 0;
     }
 #endif

lib/util/str2sig.c

@@ -36,8 +36,9 @@
 #ifdef HAVE_STRINGS_H
 # include <strings.h>
 #endif /* HAVE_STRINGS_H */
-#include <signal.h>
 #include <ctype.h>
+#include <signal.h>
+#include <unistd.h>
 
 #include "sudo_compat.h"
 
@@ -117,12 +118,17 @@ sudo_str2sig(const char *signame, int *result)
 		return 0;
 	    }
 	    if (signame[5] == '+') {
-		if (signame[6] == '1' || signame[6] == '2' || signame[6] == '3') {
-		    *result = SIGRTMIN + (signame[6] - '0');
+		if (isdigit((unsigned char)signame[6])) {
+		    const long rtmax = sysconf(_SC_RTSIG_MAX);
+		    const int off = signame[6] - '0';
+
+		    if (rtmax > 0 && off < rtmax / 2) {
+			*result = SIGRTMIN + off;
 			return 0;
 		    }
 		}
 	    }
+	}
 #endif
 #if defined(SIGRTMAX)
 	if (strncmp(signame, "RTMAX", 5) == 0) {
@@ -131,22 +137,29 @@ sudo_str2sig(const char *signame, int *result)
 		return 0;
 	    }
 	    if (signame[5] == '-') {
-		if (signame[6] == '1' || signame[6] == '2' || signame[6] == '3') {
-		    *result = SIGRTMAX - (signame[6] - '0');
+		if (isdigit((unsigned char)signame[6])) {
+		    const long rtmax = sysconf(_SC_RTSIG_MAX);
+		    const int off = signame[6] - '0';
+
+		    if (rtmax > 0 && off < rtmax / 2) {
+			*result = SIGRTMAX - off;
 			return 0;
 		    }
 		}
 	    }
+	}
 #endif
 	break;
     }
 
-    for (signo = 0; signo < NSIG; signo++) {
+    for (signo = 1; signo < NSIG; signo++) {
+	if (sudo_sys_signame[signo] != NULL) {
 	    if (strcmp(signame, sudo_sys_signame[signo]) == 0) {
 		*result = signo;
 		return 0;
 	    }
 	}
+    }
 
     errno = EINVAL;
     return -1;