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authorDenys Vlasenko <vda.linux@googlemail.com>2009-10-26 11:09:06 (GMT)
committer Denys Vlasenko <vda.linux@googlemail.com>2009-10-26 11:09:06 (GMT)
commit0f91b3d0dc85af558306f65666779c9deae5fe4a (patch)
tree578923e04741a505e389efd16086b2f38a486b64
parent180f585ac379d9eb2250d8cc4c11fbea38a1b844 (diff)
downloadbusybox-0f91b3d0dc85af558306f65666779c9deae5fe4a.tar.gz
busybox-0f91b3d0dc85af558306f65666779c9deae5fe4a.tar.bz2
read_key: ignore unknown keys (do not return them to caller byte-by-byte)
function old new delta read_key 568 601 +33 Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
-rw-r--r--libbb/read_key.c124
1 files changed, 74 insertions, 50 deletions
diff --git a/libbb/read_key.c b/libbb/read_key.c
index 02c381d..ec1b3a4 100644
--- a/libbb/read_key.c
+++ b/libbb/read_key.c
@@ -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;
}