loadkmap: explain what happens with K_ALLOCATED key value

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 19 insertions, 8 deletions

diff --git a/console-tools/loadkmap.c b/console-tools/loadkmap.c
index bcffe16b1..66ec3b043 100644
--- a/console-tools/loadkmap.c
+++ b/console-tools/loadkmap.c
@@ -48,6 +48,7 @@ int loadkmap_main(int argc UNUSED_PARAM, char **argv)
         if (argv[1])
                 bb_show_usage();
 /* bb_warn_ignoring_args(argv[1]); */
+
         fd = get_console_fd_or_die();
 /* or maybe:
         opt = getopt32(argv, "C:", &tty_name);
@@ -61,14 +62,24 @@ int loadkmap_main(int argc UNUSED_PARAM, char **argv)
         xread(STDIN_FILENO, flags, MAX_NR_KEYMAPS);
 
         for (i = 0; i < MAX_NR_KEYMAPS; i++) {
-                if (flags[i] == 1) {
-                        xread(STDIN_FILENO, ibuff, NR_KEYS * sizeof(uint16_t));
-                        for (j = 0; j < NR_KEYS; j++) {
-                                ke.kb_index = j;
-                                ke.kb_table = i;
-                                ke.kb_value = ibuff[j];
-                                ioctl(fd, KDSKBENT, &ke);
-                        }
+                if (flags[i] != 1)
+                        continue;
+                xread(STDIN_FILENO, ibuff, NR_KEYS * sizeof(uint16_t));
+                for (j = 0; j < NR_KEYS; j++) {
+                        ke.kb_index = j;
+                        ke.kb_table = i;
+                        ke.kb_value = ibuff[j];
+                        /*
+                         * Note: table[idx:0] can contain special value
+                         * K_ALLOCATED (marks allocated tables in kernel).
+                         * dumpkmap saves the value as-is; but attempts
+                         * to load it here fail, since it isn't a valid
+                         * key value: it is K(KT_SPEC,126) == 2<<8 + 126,
+                         * whereas last valid KT_SPEC is
+                         * K_BARENUMLOCK == K(KT_SPEC,19).
+                         * So far we just ignore these errors:
+                         */
+                        ioctl(fd, KDSKBENT, &ke);
                 }
         }