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cleanup(pkg/driver): use unix where available. #353

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cleanup(pkg/driver): use unix where available. #353

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66 changes: 32 additions & 34 deletions pkg/driver/type/kmod.go
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Original file line number Diff line number Diff line change
Expand Up @@ -27,6 +27,7 @@

"github.com/falcosecurity/driverkit/pkg/kernelrelease"
"golang.org/x/net/context"
"golang.org/x/sys/unix"

"github.com/falcosecurity/falcoctl/pkg/output"
)
Expand All @@ -38,14 +39,6 @@
rmmodWaitTime = 5 * time.Second
)

type errMissingDep struct {
program string
}

func (e *errMissingDep) Error() string {
return fmt.Sprintf("This program requires %s.", e.program)
}

func init() {
driverTypes[TypeKmod] = &kmod{}
}
Expand All @@ -61,40 +54,45 @@
// Then, using dkms, it tries to fetch all
// dkms-installed versions of the module to clean them up.
func (k *kmod) Cleanup(printer *output.Printer, driverName string) error {
_, err := exec.Command("bash", "-c", "hash lsmod").Output()
if err != nil {
return &errMissingDep{program: "lsmod"}
}
_, err = exec.Command("bash", "-c", "hash rmmod").Output()
if err != nil {
return &errMissingDep{program: "rmmod"}
}

kmodName := strings.ReplaceAll(driverName, "-", "_")
printer.Logger.Info("Check if kernel module is still loaded.")
lsmodCmdArgs := fmt.Sprintf(`lsmod | cut -d' ' -f1 | grep -qx %q`, kmodName)
_, err = exec.Command("bash", "-c", lsmodCmdArgs).Output() //nolint:gosec // false positive
f, err := os.Open("/proc/modules")
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Instead of using lsmod, manually scan /proc/modules.

if err == nil {
unloaded := false
// Module is still loaded, try to remove it
for i := 0; i < maxRmmodWait; i++ {
printer.Logger.Info("Kernel module is still loaded.")
printer.Logger.Info("Trying to unload it with 'rmmod'.")
if _, err = exec.Command("rmmod", kmodName).Output(); err == nil { //nolint:gosec // false positive
printer.Logger.Info("OK! Unloading module succeeded.")
unloaded = true
defer f.Close()
scanner := bufio.NewScanner(f)
found := false
// optionally, resize scanner's capacity for lines over 64K, see next example
for scanner.Scan() {
line := scanner.Text()
fields := strings.Fields(line)
if len(fields) > 0 && fields[0] == kmodName {
found = true
unloaded := false
// Module is still loaded, try to remove it
for i := 0; i < maxRmmodWait; i++ {
printer.Logger.Info("Kernel module is still loaded.")
printer.Logger.Info("Trying to unload it with 'rmmod'.")
if err = unix.DeleteModule(kmodName, 0); err == nil {

Check failure on line 75 in pkg/driver/type/kmod.go

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GitHub Actions / build (darwin, arm64) 

undefined: unix.DeleteModule

Check failure on line 75 in pkg/driver/type/kmod.go

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GitHub Actions / build (darwin, amd64) 

undefined: unix.DeleteModule
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Instead of calling rmmod directly, just use unit.DeleteModule.

printer.Logger.Info("OK! Unloading module succeeded.")
unloaded = true
break
}
printer.Logger.Info("Nothing to do...'falcoctl' will wait until you remove the kernel module to have a clean termination.")
printer.Logger.Info("Check that no process is using the kernel module with 'lsmod'.")
printer.Logger.Info("Sleep 5 seconds...")
time.Sleep(rmmodWaitTime)
}
if !unloaded {
printer.Logger.Warn("Kernel module is still loaded, you could have incompatibility issues.")
}
break
}
printer.Logger.Info("Nothing to do...'falcoctl' will wait until you remove the kernel module to have a clean termination.")
printer.Logger.Info("Check that no process is using the kernel module with 'lsmod'.")
printer.Logger.Info("Sleep 5 seconds...")
time.Sleep(rmmodWaitTime)
}
if !unloaded {
printer.Logger.Warn("Kernel module is still loaded, you could have incompatibility issues.")
if !found {
printer.Logger.Info("OK! There is no module loaded.")
}
} else {
printer.Logger.Info("OK! There is no module loaded.")
printer.Logger.Warn("Failed to parse /proc/modules.", printer.Logger.Args("err", err))
}

_, err = exec.Command("bash", "-c", "hash dkms").Output()
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