sysctl: print dotted keys again

When the globbing update was put into sysctl, you could no longer
simply use the keys because one key could potentially be
multiple paths once the glob expansion occured.  Using the path
instead gave a unique output.

Except certain programs, such as salt, expected the output to use
the dotted path "kernel.hostname" and not "kernel/hostname".

We can no longer use the original key, so now for each path:
  Copy the path
  strip off /proc/
  convert all / to .

The sysctl testsuite was also updated to check for a few different
types of conversion failures.

References:
 commit 6389deca5b
 https://www.freelists.org/post/procps/some-procpsn4400-fixes,4
 https://repo.saltproject.io/

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

NEWS

@@ -3,6 +3,7 @@ procps-ng-NEXT
     Re-add elogind support                                 merge #151
   * ps: threads again display when -L is used with -q      issue #234
   * ps: proper aix format string behavior was restored
+  * sysctl: print dotted keys again
 
 procps-ng-4.0.0
 ---------------

sysctl.c

@@ -169,7 +169,7 @@ static SysctlSetting *setting_new(
         strcat(path + proc_len, key+1);
     else
         strcat(path + proc_len, key);
-    /* change . to / */
+    /* change . to / for path */
     slashdot(path + proc_len, '.', '/');
 
     s = xmalloc(sizeof(SysctlSetting));
@@ -535,6 +535,7 @@ static int WriteSetting(
     int rc = EXIT_SUCCESS;
     FILE *fp;
     struct stat ts;
+    char *dotted_key;
 
     if (!key || !path)
         return rc;
@@ -551,13 +552,22 @@ static int WriteSetting(
         return EXIT_FAILURE;
     }
 
+    /* Convert the globbed path into a dotted key */
+    if ( (dotted_key = strdup(path + strlen(PROC_PATH))) == NULL) {
+	xerrx(EXIT_FAILURE, _("strdup key"));
+	return EXIT_FAILURE;
+    }
+    slashdot(dotted_key, '/', '.');
+
     if ((ts.st_mode & S_IWUSR) == 0) {
-        xwarn(_("setting key \"%s\""), key);
+        xwarn(_("setting key \"%s\""), dotted_key);
+	free(dotted_key);
         return rc;
     }
 
     if (S_ISDIR(ts.st_mode)) {
-        xwarn(_("setting key \"%s\""), key);
+        xwarn(_("setting key \"%s\""), dotted_key);
+	free(dotted_key);
         return rc;
     }
 
@@ -567,7 +577,7 @@ static int WriteSetting(
             case ENOENT:
                 if (!IgnoreError) {
                     xwarnx(_("\"%s\" is an unknown key%s"),
-                           key, (ignore_failure?_(", ignoring"):""));
+                           dotted_key, (ignore_failure?_(", ignoring"):""));
                     if (!ignore_failure)
                         rc = EXIT_FAILURE;
                 }
@@ -576,11 +586,11 @@ static int WriteSetting(
             case EROFS:
             case EACCES:
                 xwarnx(_("permission denied on key \"%s\"%s"),
-                       key, (ignore_failure?_(", ignoring"):""));
+                       dotted_key, (ignore_failure?_(", ignoring"):""));
                 break;
             default:
                 xwarn(_("setting key \"%s\"%s"),
-                      key, (ignore_failure?_(", ignoring"):""));
+                      dotted_key, (ignore_failure?_(", ignoring"):""));
                 break;
             }
             if (!ignore_failure && errno != ENOENT)
@@ -589,7 +599,8 @@ static int WriteSetting(
             if (0 < fprintf(fp, "%s\n", value))
                 rc = EXIT_SUCCESS;
             if (close_stream(fp) != 0) {
-                xwarn(_("setting key \"%s\""), path);
+                xwarn(_("setting key \"%s\""), dotted_key);
+		free(dotted_key);
                 return EXIT_FAILURE;
             }
         }
@@ -599,7 +610,7 @@ static int WriteSetting(
             printf("%s\n", value);
         } else {
             if (PrintName) {
-                printf("%s = %s\n", path, value);
+                printf("%s = %s\n", dotted_key, value);
             } else {
                 if (PrintNewline)
                     printf("%s\n", value);
@@ -608,6 +619,7 @@ static int WriteSetting(
             }
         }
     }
+    free(dotted_key);
     return rc;
 }
 

testsuite/sysctl.test/sysctl_write.exp

@@ -3,11 +3,19 @@ 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"
+expect_pass "$test" "kernel.hostname = procps-test"
+
+set test "sysctl write from command line using slash"
+spawn $sysctl --dry-run kernel/hostname=procps-test
+expect_pass "$test" "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"
+expect_pass "$test" "fs.protected_fifos = 2\\s+fs.protected_symlinks = 2\\s+fs.protected_hardlinks = 1"
+
+set test "sysctl write from file with slashes"
+spawn $sysctl --dry-run -f ${topdir}testsuite/sysctl_slash_test.conf
+expect_pass "$test" "kernel.hostname = procps-test"
 
 set hostname_file "/proc/sys/kernel/hostname"
 if {[file exists ${hostname_file}]} {
@@ -25,7 +33,7 @@ if {[file exists ${hostname_file}]} {
     expect_spawn_retval "$test" 0
   }
 } else {
-  unsupported "sysctl write: hostname file doe not exist"
+  unsupported "sysctl write: hostname file does not exist"
 }
 
 set test "sysctl write above /proc"

testsuite/sysctl_slash_test.conf

@@ -0,0 +1 @@
+kernel/hostname = procps-test