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ash: fix bad interaction of "stty -echo" + ASK_TERMINAL

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function                                             old     new   delta
read_line_input                                     4820    4886     +66
put_prompt                                           108      47     -61
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 1/1 up/down: 66/-61)              Total: 5 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko 2009-11-11 03:19:30 +01:00
parent b6d221ac9c
commit 13ad90627c
1 changed files with 52 additions and 47 deletions
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99
libbb/lineedit.c
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@ -372,55 +372,14 @@ static void input_backward(unsigned num)
static void put_prompt(void)
{
unsigned w;
out1str(cmdedit_prompt);
fflush_all();
#if ENABLE_FEATURE_EDITING_ASK_TERMINAL
{
/* Ask terminal where is the cursor now.
* lineedit_read_key handles response and corrects
* our idea of current cursor position.
* Testcase: run "echo -n long_line_long_line_long_line",
* then type in a long, wrapping command and try to
* delete it using backspace key.
* Note: we print it _after_ prompt, because
* prompt may contain CR. Example: PS1='\[\r\n\]\w '
*/
/* Problem: if there is buffered input on stdin,
* the response will be delivered later,
* possibly to an unsuspecting application.
* Testcase: "sleep 1; busybox ash" + press and hold [Enter].
* Result:
* ~/srcdevel/bbox/fix/busybox.t4 #
* ~/srcdevel/bbox/fix/busybox.t4 #
* ^[[59;34~/srcdevel/bbox/fix/busybox.t4 # <-- garbage
* ~/srcdevel/bbox/fix/busybox.t4 #
*
* Checking for input with poll only makes the race narrower,
* I still can trigger it. Strace:
*
* write(1, "~/srcdevel/bbox/fix/busybox.t4 # ", 33) = 33
* poll([{fd=0, events=POLLIN}], 1, 0) = 0 (Timeout) <-- no input exists
* write(1, "\33[6n", 4) = 4 <-- send the ESC sequence, quick!
* poll([{fd=0, events=POLLIN}], 1, 4294967295) = 1 ([{fd=0, revents=POLLIN}])
* read(0, "\n", 1) = 1 <-- oh crap, user's input got in first
*/
struct pollfd pfd;
pfd.fd = STDIN_FILENO;
pfd.events = POLLIN;
if (safe_poll(&pfd, 1, 0) == 0) {
S.sent_ESC_br6n = 1;
out1str("\033" "[6n");
fflush_all(); /* make terminal see it ASAP! */
}
}
#endif
cursor = 0;
{
unsigned w = cmdedit_termw; /* volatile var */
cmdedit_y = cmdedit_prmt_len / w; /* new quasireal y */
cmdedit_x = cmdedit_prmt_len % w;
}
w = cmdedit_termw; /* read volatile var once */
cmdedit_y = cmdedit_prmt_len / w; /* new quasireal y */
cmdedit_x = cmdedit_prmt_len % w;
}
/* draw prompt, editor line, and clear tail */
@ -1503,6 +1462,51 @@ static void ctrl_right(void)
* read_line_input and its helpers
*/
#if ENABLE_FEATURE_EDITING_ASK_TERMINAL
static void ask_terminal(void)
{
/* Ask terminal where is the cursor now.
* lineedit_read_key handles response and corrects
* our idea of current cursor position.
* Testcase: run "echo -n long_line_long_line_long_line",
* then type in a long, wrapping command and try to
* delete it using backspace key.
* Note: we print it _after_ prompt, because
* prompt may contain CR. Example: PS1='\[\r\n\]\w '
*/
/* Problem: if there is buffered input on stdin,
* the response will be delivered later,
* possibly to an unsuspecting application.
* Testcase: "sleep 1; busybox ash" + press and hold [Enter].
* Result:
* ~/srcdevel/bbox/fix/busybox.t4 #
* ~/srcdevel/bbox/fix/busybox.t4 #
* ^[[59;34~/srcdevel/bbox/fix/busybox.t4 # <-- garbage
* ~/srcdevel/bbox/fix/busybox.t4 #
*
* Checking for input with poll only makes the race narrower,
* I still can trigger it. Strace:
*
* write(1, "~/srcdevel/bbox/fix/busybox.t4 # ", 33) = 33
* poll([{fd=0, events=POLLIN}], 1, 0) = 0 (Timeout) <-- no input exists
* write(1, "\33[6n", 4) = 4 <-- send the ESC sequence, quick!
* poll([{fd=0, events=POLLIN}], 1, 4294967295) = 1 ([{fd=0, revents=POLLIN}])
* read(0, "\n", 1) = 1 <-- oh crap, user's input got in first
*/
struct pollfd pfd;
pfd.fd = STDIN_FILENO;
pfd.events = POLLIN;
if (safe_poll(&pfd, 1, 0) == 0) {
S.sent_ESC_br6n = 1;
out1str("\033" "[6n");
fflush_all(); /* make terminal see it ASAP! */
}
}
#else
#define ask_terminal() ((void)0)
#endif
#if !ENABLE_FEATURE_EDITING_FANCY_PROMPT
static void parse_and_put_prompt(const char *prmt_ptr)
{
@ -1822,8 +1826,9 @@ int FAST_FUNC read_line_input(const char *prompt, char *command, int maxsize, li
bb_error_msg("cur_history:%d cnt_history:%d", state->cur_history, state->cnt_history);
#endif
/* Print out the command prompt */
/* Print out the command prompt, optionally ask where cursor is */
parse_and_put_prompt(prompt);
ask_terminal();
read_key_buffer[0] = 0;
while (1) {