kdb: Eliminate strncpy() warnings by replacing with strscpy()

Currently the code to manage the kdb history buffer uses strncpy() to
copy strings to/and from the history and exhibits the classic "but
nobody ever told me that strncpy() doesn't always terminate strings"
bug. Modern gcc compilers recognise this bug and issue a warning.

In reality these calls will only abridge the copied string if kdb_read()
has *already* overflowed the command buffer. Thus the use of counted
copies here is only used to reduce the secondary effects of a bug
elsewhere in the code.

Therefore transitioning these calls into strscpy() (without checking
the return code) is appropriate.

Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>

diff --git a/kernel/debug/kdb/kdb_main.c b/kernel/debug/kdb/kdb_main.c
index ba12e9f4661ec5a8bcba4e1ec81c15df12ccef58..a4641be4123c22ebf6218ba2c62f7a862eb33665 100644 (file)
--- a/kernel/debug/kdb/kdb_main.c
+++ b/kernel/debug/kdb/kdb_main.c
@@ -1102,12 +1102,12 @@ static int handle_ctrl_cmd(char *cmd)
        case CTRL_P:
                if (cmdptr != cmd_tail)
                        cmdptr = (cmdptr-1) % KDB_CMD_HISTORY_COUNT;
-               strncpy(cmd_cur, cmd_hist[cmdptr], CMD_BUFLEN);
+               strscpy(cmd_cur, cmd_hist[cmdptr], CMD_BUFLEN);
                return 1;
        case CTRL_N:
                if (cmdptr != cmd_head)
                        cmdptr = (cmdptr+1) % KDB_CMD_HISTORY_COUNT;
-               strncpy(cmd_cur, cmd_hist[cmdptr], CMD_BUFLEN);
+               strscpy(cmd_cur, cmd_hist[cmdptr], CMD_BUFLEN);
                return 1;
        }
        return 0;
@@ -1314,7 +1314,7 @@ do_full_getstr:
                if (*cmdbuf != '\n') {
                        if (*cmdbuf < 32) {
                                if (cmdptr == cmd_head) {
-                                       strncpy(cmd_hist[cmd_head], cmd_cur,
+                                       strscpy(cmd_hist[cmd_head], cmd_cur,
                                                CMD_BUFLEN);
                                        *(cmd_hist[cmd_head] +
                                          strlen(cmd_hist[cmd_head])-1) = '\0';
@@ -1324,7 +1324,7 @@ do_full_getstr:
                                cmdbuf = cmd_cur;
                                goto do_full_getstr;
                        } else {
-                               strncpy(cmd_hist[cmd_head], cmd_cur,
+                               strscpy(cmd_hist[cmd_head], cmd_cur,
                                        CMD_BUFLEN);
                        }