X-Git-Url: http://nsz.repo.hu/git/?a=blobdiff_plain;f=src%2Funistd%2Fnice.c;h=6c25c8c326a72f26ad6d8a5359f85dc669d59d1f;hb=e95538fa07d2b460b25ee6c2fef05f820888776d;hp=da56996776e26aedd31b4c5495d24797cfbce070;hpb=c2cd25bff89c3581780e7eb267262cb8c4da0d38;p=musl

diff --git a/src/unistd/nice.c b/src/unistd/nice.c
index da569967..6c25c8c3 100644
--- a/src/unistd/nice.c
+++ b/src/unistd/nice.c
@@ -1,12 +1,16 @@
 #include <unistd.h>
 #include <sys/resource.h>
+#include <limits.h>
 #include "syscall.h"
 
 int nice(int inc)
 {
-#ifdef SYS_nice
-	return syscall(SYS_nice, inc);
-#else
-	return setpriority(PRIO_PROCESS, 0, getpriority(PRIO_PROCESS, 0)+inc);
-#endif
+	int prio = inc;
+	// Only query old priority if it can affect the result.
+	// This also avoids issues with integer overflow.
+	if (inc > -2*NZERO && inc < 2*NZERO)
+		prio += getpriority(PRIO_PROCESS, 0);
+	if (prio > NZERO-1) prio = NZERO-1;
+	if (prio < -NZERO) prio = -NZERO;
+	return setpriority(PRIO_PROCESS, 0, prio) ? -1 : prio;
 }