X-Git-Url: http://nsz.repo.hu/git/?a=blobdiff_plain;f=src%2Funistd%2Fnice.c;h=6c25c8c326a72f26ad6d8a5359f85dc669d59d1f;hb=5ef60206ff9e697d3011bcf48afca50c9fe85e1b;hp=34f7c7f9c8f3e5af47f5281aa2a088efd2d6394f;hpb=aa398f56fa398f2202b04e82c67f822f3233786f;p=musl

diff --git a/src/unistd/nice.c b/src/unistd/nice.c
index 34f7c7f9..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 __NR_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;
 }