13ad90627
Denys Vlasenko
2009-11-11
Subject
ash: fix bad interaction of "stty -echo" + ASK_TERMINAL
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Commit Diff GitHub →
libbb/lineedit.c+52 -47
| @@ -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) { | |