cpu_perc: Check for division by zero

diff --git a/components/cpu.c b/components/cpu.c
index d9bd0188249a4e19be22a8c0753f9deef3591b39..9e280031d6c9d7f58914eb4e9d7a7d0bdbcd1fda 100644 (file)
--- a/components/cpu.c
+++ b/components/cpu.c
@@ -24,7 +24,7 @@
        cpu_perc(void)
        {
                static long double a[7];
-               long double b[7];
+               long double b[7], sum;
 
                memcpy(b, a, sizeof(b));
                /* cpu user nice system idle iowait irq softirq */
@@ -37,13 +37,16 @@
                        return NULL;
                }
 
+               sum = (b[0] + b[1] + b[2] + b[3] + b[4] + b[5] + b[6]) -
+                     (a[0] + a[1] + a[2] + a[3] + a[4] + a[5] + a[6]);
+
+               if (sum == 0) {
+                       return NULL;
+               }
+
                return bprintf("%d", (int)(100 *
                               ((b[0] + b[1] + b[2] + b[5] + b[6]) -
-                               (a[0] + a[1] + a[2] + a[5] + a[6])) /
-                              ((b[0] + b[1] + b[2] + b[3] + b[4] + b[5] +
-                                b[6]) -
-                               (a[0] + a[1] + a[2] + a[3] + a[4] + a[5] +
-                                a[6]))));
+                               (a[0] + a[1] + a[2] + a[5] + a[6])) / sum));
        }
 #elif defined(__OpenBSD__)
        #include <sys/param.h>
@@ -75,7 +78,7 @@
        {
                int mib[2];
                static uintmax_t a[CPUSTATES];
-               uintmax_t b[CPUSTATES];
+               uintmax_t b[CPUSTATES], sum;
                size_t size;
 
                mib[0] = CTL_KERN;
@@ -92,15 +95,18 @@
                        return NULL;
                }
 
+               sum = (a[CP_USER] + a[CP_NICE] + a[CP_SYS] + a[CP_INTR] + a[CP_IDLE]) -
+                     (b[CP_USER] + b[CP_NICE] + b[CP_SYS] + b[CP_INTR] + b[CP_IDLE]);
+
+               if (sum == 0) {
+                       return NULL;
+               }
+
                return bprintf("%d", 100 *
                               ((a[CP_USER] + a[CP_NICE] + a[CP_SYS] +
                                 a[CP_INTR]) -
                                (b[CP_USER] + b[CP_NICE] + b[CP_SYS] +
-                                b[CP_INTR])) /
-                              ((a[CP_USER] + a[CP_NICE] + a[CP_SYS] +
-                                a[CP_INTR] + a[CP_IDLE]) -
-                               (b[CP_USER] + b[CP_NICE] + b[CP_SYS] +
-                                b[CP_INTR] + b[CP_IDLE])));
+                                b[CP_INTR])) / sum);
        }
 #elif defined(__FreeBSD__)
        #include <sys/param.h>
@@ -129,7 +135,7 @@
        {
                size_t size;
                static long a[CPUSTATES];
-               long b[CPUSTATES];
+               long b[CPUSTATES], sum;
 
                size = sizeof(a);
                memcpy(b, a, sizeof(b));
@@ -142,14 +148,17 @@
                        return NULL;
                }
 
+               sum = (a[CP_USER] + a[CP_NICE] + a[CP_SYS] + a[CP_INTR] + a[CP_IDLE]) -
+                     (b[CP_USER] + b[CP_NICE] + b[CP_SYS] + b[CP_INTR] + b[CP_IDLE]);
+
+               if (sum == 0) {
+                       return NULL;
+               }
+
                return bprintf("%d", 100 *
                               ((a[CP_USER] + a[CP_NICE] + a[CP_SYS] +
                                 a[CP_INTR]) -
                                (b[CP_USER] + b[CP_NICE] + b[CP_SYS] +
-                                b[CP_INTR])) /
-                              ((a[CP_USER] + a[CP_NICE] + a[CP_SYS] +
-                                a[CP_INTR] + a[CP_IDLE]) -
-                               (b[CP_USER] + b[CP_NICE] + b[CP_SYS] +
-                                b[CP_INTR] + b[CP_IDLE])));
+                                b[CP_INTR])) / sum);
        }
 #endif