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-rw-r--r--src/unistd/nice.c14
1 files changed, 9 insertions, 5 deletions
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;
}