[Qemu-devel] [PATCH 1/2] Refactor und fix do_sendkey

[Jan Kiszka <jan.kiszka@web.de>]

Looking at the sendkey implementation, planning to enhance it with a
hold time argument, I found some potential out-of-bound access and not
very readable code. Here is a fix for the former and a (subjective)
improvement of the latter.

Signed-off-by: Jan Kiszka <jan.kiszka@web.de>
---
 monitor.c |   52 +++++++++++++++++++++++++++++-----------------------
 1 file changed, 29 insertions(+), 23 deletions(-)

Index: b/monitor.c
===================================================================
--- a/monitor.c
+++ b/monitor.c
@@ -925,33 +925,39 @@ static int get_keycode(const char *key)
     return -1;
 }
 
-static void do_send_key(const char *string)
+static void do_sendkey(const char *string)
 {
-    char keybuf[16], *q;
     uint8_t keycodes[16];
-    const char *p;
-    int nb_keycodes, keycode, i;
-
-    nb_keycodes = 0;
-    p = string;
-    while (*p != '\0') {
-        q = keybuf;
-        while (*p != '\0' && *p != '-') {
-            if ((q - keybuf) < sizeof(keybuf) - 1) {
-                *q++ = *p;
+    int nb_keycodes = 0;
+    char keyname_buf[16];
+    char *separator;
+    int keyname_len, keycode, i;
+
+    while (1) {
+        separator = strchr(string, '-');
+        keyname_len = separator ? separator-string : strlen(string);
+        if (keyname_len > 0) {
+            strncpy(keyname_buf, string, sizeof(keyname_buf) - 1);
+            if (keyname_len > sizeof(keyname_buf) - 1) {
+                keyname_buf[sizeof(keyname_buf) - 1] = 0;
+                term_printf("invalid key: '%s...'\n", keyname_buf);
+                return;
             }
-            p++;
-        }
-        *q = '\0';
-        keycode = get_keycode(keybuf);
-        if (keycode < 0) {
-            term_printf("unknown key: '%s'\n", keybuf);
-            return;
+            if (nb_keycodes == sizeof(keycodes)) {
+                term_printf("too many keys\n");
+                return;
+            }
+            keyname_buf[keyname_len] = 0;
+            keycode = get_keycode(keyname_buf);
+            if (keycode < 0) {
+                term_printf("unknown key: '%s'\n", keyname_buf);
+                return;
+            }
+            keycodes[nb_keycodes++] = keycode;
         }
-        keycodes[nb_keycodes++] = keycode;
-        if (*p == '\0')
+        if (!separator)
             break;
-        p++;
+        string = separator + 1;
     }
     /* key down events */
     for(i = 0; i < nb_keycodes; i++) {
@@ -1353,7 +1359,7 @@ static term_cmd_t term_cmds[] = {
     { "i", "/ii.", do_ioport_read,
       "/fmt addr", "I/O port read" },
 
-    { "sendkey", "s", do_send_key,
+    { "sendkey", "s", do_sendkey,
       "keys", "send keys to the VM (e.g. 'sendkey ctrl-alt-f1')" },
     { "system_reset", "", do_system_reset,
       "", "reset the system" },