From f472b237a1590bd4a20cb89ac6edc5f8a19ddbf3 Mon Sep 17 00:00:00 2001 From: Denis Vlasenko Date: Tue, 16 Oct 2007 21:35:17 +0000 Subject: [PATCH] telnetd: code shrink suggested by Ralf Friedl --- networking/telnetd.c | 67 ++++++++++++++++++++++++++++------------------------ 1 file changed, 36 insertions(+), 31 deletions(-) diff --git a/networking/telnetd.c b/networking/telnetd.c index eb37011..f06bff8 100644 --- a/networking/telnetd.c +++ b/networking/telnetd.c @@ -203,7 +203,7 @@ getpty(char *line, int size) static struct tsession * make_new_session( - USE_FEATURE_TELNETD_STANDALONE(int sock_r, int sock_w) + USE_FEATURE_TELNETD_STANDALONE(int sock) SKIP_FEATURE_TELNETD_STANDALONE(void) ) { const char *login_argv[2]; @@ -221,19 +221,22 @@ make_new_session( bb_error_msg("can't create pty"); return NULL; } - if (fd > maxfd) maxfd = fd; + if (fd > maxfd) + maxfd = fd; ts->ptyfd = fd; ndelay_on(fd); #if ENABLE_FEATURE_TELNETD_STANDALONE - if (sock_w > maxfd) maxfd = sock_w; - ts->sockfd_write = sock_w; - ndelay_on(sock_w); - if (sock_r > maxfd) maxfd = sock_r; - ts->sockfd_read = sock_r; - ndelay_on(sock_r); + ts->sockfd_read = sock; + ndelay_on(sock); + if (!sock) /* We are called with fd 0 - we are in inetd mode */ + sock++; + ts->sockfd_write = sock; + ndelay_on(sock); + if (sock > maxfd) + maxfd = sock; #else - ts->sockfd_write = 1; /* ts->sockfd_read = 0; - done by xzalloc */ + ts->sockfd_write = 1; ndelay_on(0); ndelay_on(1); #endif @@ -326,27 +329,33 @@ free_session(struct tsession *ts) t->next = ts->next; } +#if 0 /* It was said that "normal" telnetd just closes ptyfd, * doesn't send SIGKILL. When we close ptyfd, * kernel sends SIGHUP to processes having slave side opened. */ - /*kill(ts->shell_pid, SIGKILL); - wait4(ts->shell_pid, NULL, 0, NULL);*/ + kill(ts->shell_pid, SIGKILL); + wait4(ts->shell_pid, NULL, 0, NULL); +#endif close(ts->ptyfd); close(ts->sockfd_read); - /* error if ts->sockfd_read == ts->sockfd_write. So what? ;) */ - close(ts->sockfd_write); + /* We do not need to close(ts->sockfd_write), it's the same + * as sockfd_read unless we are in inetd mode. But in inetd mode + * we do not free_session(), ever */ free(ts); /* Scan all sessions and find new maxfd */ - ts = sessions; maxfd = 0; + ts = sessions; while (ts) { if (maxfd < ts->ptyfd) maxfd = ts->ptyfd; if (maxfd < ts->sockfd_read) maxfd = ts->sockfd_read; +#if 0 + /* Again, sockfd_write == sockfd_read here */ if (maxfd < ts->sockfd_write) maxfd = ts->sockfd_write; +#endif ts = ts->next; } } @@ -434,7 +443,7 @@ int telnetd_main(int argc, char **argv) #if ENABLE_FEATURE_TELNETD_STANDALONE if (IS_INETD) { - sessions = make_new_session(0, 1); + sessions = make_new_session(0); if (!sessions) /* pty opening or vfork problem, exit */ return 1; /* make_new_session prints error message */ } else { @@ -519,7 +528,7 @@ int telnetd_main(int argc, char **argv) if (fd < 0) goto again; /* Create a new session and link it into our active list */ - new_ts = make_new_session(fd, fd); + new_ts = make_new_session(fd); if (new_ts) { new_ts->next = sessions; sessions = new_ts; @@ -545,9 +554,7 @@ int telnetd_main(int argc, char **argv) goto skip1; if (IS_INETD) return 0; - free_session(ts); - ts = next; - continue; + goto kill_session; } ts->size1 -= count; ts->wridx1 += count; @@ -564,9 +571,7 @@ int telnetd_main(int argc, char **argv) goto skip2; if (IS_INETD) return 0; - free_session(ts); - ts = next; - continue; + goto kill_session; } ts->size2 -= count; ts->wridx2 += count; @@ -577,7 +582,7 @@ int telnetd_main(int argc, char **argv) /* Should not be needed, but... remove_iacs is actually buggy * (it cannot process iacs which wrap around buffer's end)! * Since properly fixing it requires writing bigger code, - * we will rely instead on this code making it virtually impossible + * we rely instead on this code making it virtually impossible * to have wrapped iac (people don't type at 2k/second). * It also allows for bigger reads in common case. */ if (ts->size1 == 0) { @@ -598,14 +603,11 @@ int telnetd_main(int argc, char **argv) goto skip3; if (IS_INETD) return 0; - free_session(ts); - ts = next; - continue; + goto kill_session; } /* Ignore trailing NUL if it is there */ if (!TS_BUF1[ts->rdidx1 + count - 1]) { - if (!--count) - goto skip3; + --count; } ts->size1 += count; ts->rdidx1 += count; @@ -622,9 +624,7 @@ int telnetd_main(int argc, char **argv) goto skip4; if (IS_INETD) return 0; - free_session(ts); - ts = next; - continue; + goto kill_session; } ts->size2 += count; ts->rdidx2 += count; @@ -633,6 +633,11 @@ int telnetd_main(int argc, char **argv) } skip4: ts = next; + continue; + kill_session: + free_session(ts); + ts = next; } + goto again; } -- 2.7.4