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

["M. Warner Losh" <imp@bsdimp.com>]

In message: <48359204.80200@web.de>
            Jan Kiszka <jan.kiszka@web.de> writes:
: Fabrice Bellard wrote:
: > Please avoid strncpy. Use pstrcpy intead.
: 
: Ah, non-POSIX host platforms. Wouldn't it be easier to provide POSIX
: wrappers for those few OSes?

strncpy is plain, vanilla C.  However, its use is dangerous and very
often used wrong.

Warner

: However, fixed-up version follows:
: 
: -----------
: 
: 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) {
: +            pstrcpy(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" },
: 
: 
: