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authorDenys Vlasenko <vda.linux@googlemail.com>2019-01-06 19:06:01 +0100
committerDenys Vlasenko <vda.linux@googlemail.com>2019-01-06 19:06:01 +0100
commit39b18196f89a6f595d47c2a9c3a62c50d413c054 (patch)
treeef4db62c99834be553c79d7f00daff22f0620456
parent935afafcf37e38290e4cc126e328a02877d74fc0 (diff)
downloadbusybox-39b18196f89a6f595d47c2a9c3a62c50d413c054.tar.gz
telnetd: fix bad interaction with vhangup() from login
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
-rw-r--r--networking/telnetd.c18
1 files changed, 16 insertions, 2 deletions
diff --git a/networking/telnetd.c b/networking/telnetd.c
index a6bafa21d..caef15181 100644
--- a/networking/telnetd.c
+++ b/networking/telnetd.c
@@ -865,11 +865,25 @@ int telnetd_main(int argc UNUSED_PARAM, char **argv)
skip3:
if (/*ts->size2 < BUFSIZE &&*/ FD_ISSET(ts->ptyfd, &rdfdset)) {
/* Read from pty to buffer 2 */
+ int eio = 0;
+ read_pty:
count = MIN(BUFSIZE - ts->rdidx2, BUFSIZE - ts->size2);
count = safe_read(ts->ptyfd, TS_BUF2(ts) + ts->rdidx2, count);
if (count <= 0) {
- if (count < 0 && errno == EAGAIN)
- goto skip4;
+ if (count < 0) {
+ if (errno == EAGAIN)
+ goto skip4;
+ /* login process might call vhangup(),
+ * which causes intermittent EIOs on read above
+ * (observed on kernel 4.12.0). Try up to 10 ms.
+ */
+ if (errno == EIO && eio < 10) {
+ eio++;
+ //bb_error_msg("EIO pty %u", eio);
+ usleep(1000);
+ goto read_pty;
+ }
+ }
goto kill_session;
}
ts->size2 += count;