sysctl: Support systemd glob patterns

systemd-sysctl handles glob patterns along with overrides and
exceptions. Now the procps sysctl does it too.

The return value for sysctl is consistently either 0 or 1.

Added tests to check sysctl functions.

References:
 procps-ng/procps#191

Signed-off-by: Craig Small <csmall@dropbear.xyz>

testsuite/config/unix.exp

@@ -136,6 +136,15 @@ proc expect_table_dsc { test match_header match_item } {
     #}
 }
 
+proc expect_spawn_retval { test retval } {
+    foreach {pid spawnid os_error_flag value} [wait] break
+
+    if {$value == $retval} {
+      return
+    }
+    fail "$test (exit value)"
+}
+
 proc make_pipeproc { } {
     global pipeproc_pid pipeproc_spawnid topdir
 

testsuite/sysctl.test/sysctl_write.exp

@@ -0,0 +1,29 @@
+
+set sysctl ${topdir}sysctl
+
+set test "sysctl write from command line"
+spawn $sysctl --dry-run kernel.hostname=procps-test
+expect_pass "$test" "/proc/sys/kernel/hostname = procps-test"
+
+set test "sysctl write from configuration file"
+spawn $sysctl --dry-run -f ${topdir}testsuite/sysctl_glob_test.conf
+expect_pass "$test" "/proc/sys/fs/protected_fifos = 2\\s+/proc/sys/fs/protected_symlinks = 2\\s+/proc/sys/fs/protected_hardlinks = 1"
+
+set hostname_file "/proc/sys/kernel/hostname"
+if {[file exists ${hostname_file}]} {
+  if {[file writable ${hostname_file}]} {
+    unsupported "sysctl write: hostname file is writable"
+  } else {
+    set test "sysctl write unwritable file"
+    spawn $sysctl -q kernel.hostname=procpstest
+    expect_pass "$test" "sysctl: permission denied on key \"kernel.hostname\"\\s*$"
+    expect_spawn_retval "$test" 1
+
+    set test "sysctl write unwritable file ignored"
+    spawn $sysctl -q -- -kernel.hostname=procpstest
+    expect_pass "$test" "sysctl: permission denied on key \"kernel.hostname\", ignoring\\s*$"
+    expect_spawn_retval "$test" 0
+  }
+} else {
+  unsupported "sysctl write: hostname file doe not exist"
+}

testsuite/sysctl_glob_test.conf

@@ -0,0 +1,6 @@
+#
+# Test configuration for for glob in sysctl
+#
+fs.protected_* = 2
+fs.protected_hardlinks = 1
+-fs.protected_regular