0f91b3d0d
Denys Vlasenko
2009-10-26
Subject
read_key: ignore unknown keys (do not return them to caller byte-by-byte)
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libbb/read_key.c+74 -50
| @@ -14,7 +14,6 @@ int64_t FAST_FUNC read_key(int fd, char *buffer) | |
| struct pollfd pfd; | |
| const char *seq; | |
| int n; | |
| - | int c; |
| /* Known escape sequences for cursor and function keys */ | |
| static const char esccmds[] ALIGN1 = { | |
| @@ -91,8 +90,11 @@ int64_t FAST_FUNC read_key(int fd, char *buffer) | |
| /* ESC [ Z - Shift-Tab */ | |
| }; | |
| + | buffer++; /* saved chars counter is in buffer[-1] now */ |
| + | |
| + | start_over: |
| errno = 0; | |
| - | n = (unsigned char) *buffer++; |
| + | n = (unsigned char)buffer[-1]; |
| if (n == 0) { | |
| /* If no data, block waiting for input. | |
| * It is tempting to read more than one byte here, | |
| @@ -106,15 +108,17 @@ int64_t FAST_FUNC read_key(int fd, char *buffer) | |
| return -1; | |
| } | |
| - | /* Grab character to return from buffer */ |
| - | c = (unsigned char)buffer[0]; |
| - | n--; |
| - | if (n) |
| - | memmove(buffer, buffer + 1, n); |
| - | |
| - | /* Only ESC starts ESC sequences */ |
| - | if (c != 27) |
| - | goto ret; |
| + | { |
| + | unsigned char c = buffer[0]; |
| + | n--; |
| + | if (n) |
| + | memmove(buffer, buffer + 1, n); |
| + | /* Only ESC starts ESC sequences */ |
| + | if (c != 27) { |
| + | buffer[-1] = n; |
| + | return c; |
| + | } |
| + | } |
| /* Loop through known ESC sequences */ | |
| pfd.fd = fd; | |
| @@ -136,17 +140,21 @@ int64_t FAST_FUNC read_key(int fd, char *buffer) | |
| if (safe_poll(&pfd, 1, 50) == 0) { | |
| /* No more data! | |
| * Array is sorted from shortest to longest, | |
| - | * we can't match anything later in array, |
| - | * break out of both loops. */ |
| - | goto ret; |
| + | * we can't match anything later in array - |
| + | * anything later is longer than this seq. |
| + | * Break out of both loops. */ |
| + | goto got_all; |
| } | |
| errno = 0; | |
| if (safe_read(fd, buffer + n, 1) <= 0) { | |
| /* If EAGAIN, then fd is O_NONBLOCK and poll lied: | |
| * in fact, there is no data. */ | |
| - | if (errno != EAGAIN) |
| - | c = -1; /* otherwise it's EOF/error */ |
| - | goto ret; |
| + | if (errno != EAGAIN) { |
| + | /* otherwise: it's EOF/error */ |
| + | buffer[-1] = 0; |
| + | return -1; |
| + | } |
| + | goto got_all; |
| } | |
| n++; | |
| } | |
| @@ -162,66 +170,82 @@ int64_t FAST_FUNC read_key(int fd, char *buffer) | |
| } | |
| if (seq[i] & 0x80) { | |
| /* Entire seq matched */ | |
| - | c = (signed char)seq[i+1]; |
| n = 0; | |
| /* n -= i; memmove(...); | |
| * would be more correct, | |
| * but we never read ahead that much, | |
| * and n == i here. */ | |
| - | goto ret; |
| + | buffer[-1] = 0; |
| + | return (signed char)seq[i+1]; |
| } | |
| i++; | |
| } | |
| } | |
| - | /* We did not find matching sequence, it was a bare ESC. |
| - | * We possibly read and stored more input in buffer[] by now. */ |
| + | /* We did not find matching sequence. |
| + | * We possibly read and stored more input in buffer[] by now. |
| + | * n = bytes read. Try to read more until we time out. |
| + | */ |
| + | while (n < KEYCODE_BUFFER_SIZE-1) { /* 1 for count byte at buffer[-1] */ |
| + | if (safe_poll(&pfd, 1, 50) == 0) { |
| + | /* No more data! */ |
| + | break; |
| + | } |
| + | errno = 0; |
| + | if (safe_read(fd, buffer + n, 1) <= 0) { |
| + | /* If EAGAIN, then fd is O_NONBLOCK and poll lied: |
| + | * in fact, there is no data. */ |
| + | if (errno != EAGAIN) { |
| + | /* otherwise: it's EOF/error */ |
| + | buffer[-1] = 0; |
| + | return -1; |
| + | } |
| + | break; |
| + | } |
| + | n++; |
| + | } |
| + | got_all: |
| + | |
| + | if (n <= 1) { |
| + | /* Alt-x is usually returned as ESC x. |
| + | * Report ESC, x is remembered for the next call. |
| + | */ |
| + | buffer[-1] = n; |
| + | return 27; |
| + | } |
| /* Try to decipher "ESC [ NNN ; NNN R" sequence */ | |
| if (ENABLE_FEATURE_EDITING_ASK_TERMINAL | |
| - | && n != 0 |
| + | && n >= 5 |
| && buffer[0] == '[' | |
| + | && isdigit(buffer[1]) |
| + | && buffer[n-1] == 'R' |
| ) { | |
| char *end; | |
| unsigned long row, col; | |
| - | while (n < KEYCODE_BUFFER_SIZE-1) { /* 1 for cnt */ |
| - | if (safe_poll(&pfd, 1, 50) == 0) { |
| - | /* No more data! */ |
| - | break; |
| - | } |
| - | errno = 0; |
| - | if (safe_read(fd, buffer + n, 1) <= 0) { |
| - | /* If EAGAIN, then fd is O_NONBLOCK and poll lied: |
| - | * in fact, there is no data. */ |
| - | if (errno != EAGAIN) |
| - | c = -1; /* otherwise it's EOF/error */ |
| - | goto ret; |
| - | } |
| - | if (buffer[n++] == 'R') |
| - | goto got_R; |
| - | } |
| - | goto ret; |
| - | got_R: |
| - | if (!isdigit(buffer[1])) |
| - | goto ret; |
| row = strtoul(buffer + 1, &end, 10); | |
| if (*end != ';' || !isdigit(end[1])) | |
| - | goto ret; |
| + | goto not_R; |
| col = strtoul(end + 1, &end, 10); | |
| if (*end != 'R') | |
| - | goto ret; |
| + | goto not_R; |
| if (row < 1 || col < 1 || (row | col) > 0x7fff) | |
| - | goto ret; |
| + | goto not_R; |
| buffer[-1] = 0; | |
| /* Pack into "1 <row15bits> <col16bits>" 32-bit sequence */ | |
| - | c = (((-1 << 15) | row) << 16) | col; |
| + | col |= (((-1 << 15) | row) << 16); |
| /* Return it in high-order word */ | |
| - | return ((int64_t) c << 32) | (uint32_t)KEYCODE_CURSOR_POS; |
| + | return ((int64_t) col << 32) | (uint32_t)KEYCODE_CURSOR_POS; |
| } | |
| + | not_R: |
| - | ret: |
| - | buffer[-1] = n; |
| - | return c; |
| + | /* We were doing "buffer[-1] = n; return c;" here, but this results |
| + | * in unknown key sequences being interpreted as ESC + garbage. |
| + | * This was not useful. Pretend there was no key pressed, |
| + | * go and wait for a new keypress: |
| + | */ |
| + | buffer[-1] = 0; |
| + | goto start_over; |
| } | |