BSD platforms: Reject negative and zero KERN_FSCALE factors

The "fscale" value, retrieved by sysctl() in BSD platforms, is used for computing CPU percentages of the processes. To prevent a division by zero, we should reject a zero "fscale" value. (A negative "fscale" value will not make sense either.) For DragonFlyBSD and FreeBSD, this would fall back to the hard-coded default scale. For NetBSD and OpenBSD, there is no hard-coded default value, so the zero or negative "fscale" is now a fatal error. Signed-off-by: Kang-Che Sung <[email protected]>
htop-dev · Aug 3, 2023 · 03c517d · 03c517d
1 parent 69b9ce1
commit 03c517d
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Showing 4 changed files with 4 additions and 4 deletions.
diff --git a/dragonflybsd/DragonFlyBSDMachine.c b/dragonflybsd/DragonFlyBSDMachine.c
@@ -105,7 +105,7 @@ Machine* Machine_new(UsersTable* usersTable, uid_t userId) {
    }
 
    len = sizeof(this->kernelFScale);
-   if (sysctlbyname("kern.fscale", &this->kernelFScale, &len, NULL, 0) == -1) {
+   if (sysctlbyname("kern.fscale", &this->kernelFScale, &len, NULL, 0) == -1 || this->kernelFScale <= 0) {
       //sane default for kernel provided CPU percentage scaling, at least on x86 machines, in case this sysctl call failed
       this->kernelFScale = 2048;
    }

diff --git a/freebsd/FreeBSDMachine.c b/freebsd/FreeBSDMachine.c
@@ -136,7 +136,7 @@ Machine* Machine_new(UsersTable* usersTable, uid_t userId) {
    }
 
    len = sizeof(this->kernelFScale);
-   if (sysctlbyname("kern.fscale", &this->kernelFScale, &len, NULL, 0) == -1) {
+   if (sysctlbyname("kern.fscale", &this->kernelFScale, &len, NULL, 0) == -1 || this->kernelFScale <= 0) {
       //sane default for kernel provided CPU percentage scaling, at least on x86 machines, in case this sysctl call failed
       this->kernelFScale = 2048;
    }

diff --git a/netbsd/NetBSDMachine.c b/netbsd/NetBSDMachine.c
@@ -112,7 +112,7 @@ Machine* Machine_new(UsersTable* usersTable, uid_t userId) {
    NetBSDMachine_updateCPUcount(this);
 
    size = sizeof(this->fscale);
-   if (sysctl(fmib, 2, &this->fscale, &size, NULL, 0) < 0) {
+   if (sysctl(fmib, 2, &this->fscale, &size, NULL, 0) < 0 || this->fscale <= 0) {
       CRT_fatalError("fscale sysctl call failed");
    }
 

diff --git a/openbsd/OpenBSDMachine.c b/openbsd/OpenBSDMachine.c
@@ -99,7 +99,7 @@ Machine* Machine_new(UsersTable* usersTable, uid_t userId) {
    OpenBSDProcessList_updateCPUcount(this);
 
    size = sizeof(this->fscale);
-   if (sysctl(fmib, 2, &this->fscale, &size, NULL, 0) < 0) {
+   if (sysctl(fmib, 2, &this->fscale, &size, NULL, 0) < 0 || this->fscale <= 0) {
       CRT_fatalError("fscale sysctl call failed");
    }