chat: hopefully fix infinite spinning on input EOF

function                                             old     new   delta
chat_main                                           1295    1303      +8

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 34 insertions, 30 deletions

diff --git a/miscutils/chat.c b/miscutils/chat.c
index f9e12a4ac..83aac37de 100644
--- a/miscutils/chat.c
+++ b/miscutils/chat.c
@@ -201,6 +201,9 @@ int chat_main(int argc UNUSED_PARAM, char **argv)
                 DIR_RECORD,
         };
 
+#define inbuf bb_common_bufsiz1
+        setup_common_bufsiz();
+
         // make x* functions fail with correct exitcode
         xfunc_error_retval = ERR_IO;
 
@@ -361,35 +364,36 @@ int chat_main(int argc UNUSED_PARAM, char **argv)
                         // get reply
                         pfd.fd = STDIN_FILENO;
                         pfd.events = POLLIN;
-                        while (!exitcode
+                        while (exitcode == ERR_OK
                             && poll(&pfd, 1, timeout) > 0
-                            && (pfd.revents & POLLIN)
+                            /* && (pfd.revents & POLLIN) - may be untrue (e.g. only POLLERR set) */
                         ) {
                                 llist_t *l;
                                 ssize_t delta;
-#define buf bb_common_bufsiz1
-                                setup_common_bufsiz();
 
                                 // read next char from device
-                                if (safe_read(STDIN_FILENO, buf+buf_len, 1) > 0) {
-                                        // dump device input if RECORD fname
-                                        if (record_fd > 0) {
-                                                full_write(record_fd, buf+buf_len, 1);
-                                        }
-                                        // dump device input if ECHO ON
-                                        if (echo) {
-//                                              if (buf[buf_len] < ' ') {
-//                                                      full_write2_str("^");
-//                                                      buf[buf_len] += '@';
-//                                              }
-                                                full_write(STDERR_FILENO, buf+buf_len, 1);
-                                        }
-                                        buf_len++;
-                                        // move input frame if we've reached higher bound
-                                        if (buf_len > COMMON_BUFSIZE) {
-                                                memmove(buf, buf+buf_len-max_len, max_len);
-                                                buf_len = max_len;
-                                        }
+                                if (safe_read(STDIN_FILENO, inbuf + buf_len, 1) <= 0) {
+                                        exitcode = ERR_IO;
+                                        goto expect_done;
+                                }
+
+                                // dump device input if RECORD fname
+                                if (record_fd > 0) {
+                                        full_write(record_fd, inbuf + buf_len, 1);
+                                }
+                                // dump device input if ECHO ON
+                                if (echo) {
+//                                      if (inbuf[buf_len] < ' ') {
+//                                              full_write2_str("^");
+//                                              inbuf[buf_len] += '@';
+//                                      }
+                                        full_write(STDERR_FILENO, inbuf + buf_len, 1);
+                                }
+                                buf_len++;
+                                // move input frame if we've reached higher bound
+                                if (buf_len > COMMON_BUFSIZE) {
+                                        memmove(inbuf, inbuf + buf_len - max_len, max_len);
+                                        buf_len = max_len;
                                 }
                                 // N.B. rule of thumb: values being looked for can
                                 // be found only at the end of input buffer
@@ -399,20 +403,20 @@ int chat_main(int argc UNUSED_PARAM, char **argv)
                                 // abort condition is met? -> bail out
                                 for (l = aborts, exitcode = ERR_ABORT; l; l = l->link, ++exitcode) {
                                         size_t len = strlen(l->data);
-                                        delta = buf_len-len;
-                                        if (delta >= 0 && !memcmp(buf+delta, l->data, len))
+                                        delta = buf_len - len;
+                                        if (delta >= 0 && !memcmp(inbuf + delta, l->data, len))
                                                 goto expect_done;
                                 }
                                 exitcode = ERR_OK;
 
                                 // expected reply received? -> goto next command
                                 delta = buf_len - expect_len;
-                                if (delta >= 0 && !memcmp(buf+delta, expect, expect_len))
+                                if (delta >= 0 && memcmp(inbuf + delta, expect, expect_len) == 0)
                                         goto expect_done;
-#undef buf
                         } /* while (have data) */
 
-                        // device timed out or unexpected reply received
+                        // device timed out, or unexpected reply received,
+                        // or we got a signal (poll() returned -1 with EINTR).
                         exitcode = ERR_TIMEOUT;
  expect_done:
 #if ENABLE_FEATURE_CHAT_NOFAIL
@@ -434,7 +438,7 @@ int chat_main(int argc UNUSED_PARAM, char **argv)
                         }
 #endif
                         // bail out unless we expected successfully
-                        if (exitcode)
+                        if (exitcode != ERR_OK)
                                 break;
 
                         //-----------------------
@@ -478,7 +482,7 @@ int chat_main(int argc UNUSED_PARAM, char **argv)
                                                         continue;
                                                 }
                                                 if ('p' == c) {
-                                                        usleep(10000);
+                                                        msleep(10);
                                                         len--;
                                                         continue;
                                                 }