github.com/meulengracht/snapd@v0.0.0-20210719210640-8bde69bcc84e/systemd/sysctl.go (about)

     1  // -*- Mode: Go; indent-tabs-mode: t -*-
     2  
     3  /*
     4   * Copyright (C) 2020 Canonical Ltd
     5   *
     6   * This program is free software: you can redistribute it and/or modify
     7   * it under the terms of the GNU General Public License version 3 as
     8   * published by the Free Software Foundation.
     9   *
    10   * This program is distributed in the hope that it will be useful,
    11   * but WITHOUT ANY WARRANTY; without even the implied warranty of
    12   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    13   * GNU General Public License for more details.
    14   *
    15   * You should have received a copy of the GNU General Public License
    16   * along with this program.  If not, see <http://www.gnu.org/licenses/>.
    17   *
    18   */
    19  
    20  package systemd
    21  
    22  import (
    23  	"fmt"
    24  	"os/exec"
    25  
    26  	"github.com/snapcore/snapd/osutil"
    27  )
    28  
    29  var (
    30  	systemdSysctlPath = "/lib/systemd/systemd-sysctl"
    31  )
    32  
    33  var systemdSysctlCmd = func(args ...string) error {
    34  	bs, err := exec.Command(systemdSysctlPath, args...).CombinedOutput()
    35  	if err != nil {
    36  		exitCode, _ := osutil.ExitCode(err)
    37  		return fmt.Errorf("%s invoked with %v failed with exit status %d: %s", systemdSysctlPath, args, exitCode, bs)
    38  	}
    39  	return nil
    40  }
    41  
    42  // Sysctl invokes systemd-sysctl to configure sysctl(8) kernel parameters
    43  // from disk configuration. A set of prefixes can be passed to limit
    44  // which settings are (re)configured.
    45  func Sysctl(prefixes []string) error {
    46  	args := []string{}
    47  	for _, p := range prefixes {
    48  		args = append(args, "--prefix", p)
    49  	}
    50  	return systemdSysctlCmd(args...)
    51  }
    52  
    53  // MockSystemdSysctl lets mock and intercept calls to systemd-sysctl
    54  // from the package.
    55  func MockSystemdSysctl(f func(args ...string) error) func() {
    56  	oldsystemdSysctlCmd := systemdSysctlCmd
    57  	systemdSysctlCmd = f
    58  	return func() {
    59  		systemdSysctlCmd = oldsystemdSysctlCmd
    60  	}
    61  }