From 96c0084bca9ef179e6e19fc77d8d67ebc1b8088b Mon Sep 17 00:00:00 2001 From: Rob Landley Date: Sat, 31 Mar 2018 19:39:46 -0500 Subject: Use XVFORK() macro, add option ranges, make lookup_port() check /etc/services, remove redundant CLOEXEC (xsocket does it) and CFG_NETCAT_LISTEN test (we're not doing FORCE_FLAGS so FLAG_L and FLAG_l become zero), remove comments about vfork triggering compiler/libc bugs (XVFORK handles it). --- toys/net/netcat.c | 55 ++++++++++++++++++++++++++----------------------------- 1 file changed, 26 insertions(+), 29 deletions(-) diff --git a/toys/net/netcat.c b/toys/net/netcat.c index 795f7b3c..cabc7e80 100644 --- a/toys/net/netcat.c +++ b/toys/net/netcat.c @@ -3,9 +3,11 @@ * Copyright 2007 Rob Landley * * TODO: udp, ipv6, genericize for telnet/microcom/tail-f + * fix -t, xconnect + * netcat -L zombies USE_NETCAT(OLDTOY(nc, netcat, TOYFLAG_USR|TOYFLAG_BIN)) -USE_NETCAT(NEWTOY(netcat, USE_NETCAT_LISTEN("^tlL")"w#W#p#s:q#f:"USE_NETCAT_LISTEN("[!tlL][!Lw]"), TOYFLAG_BIN)) +USE_NETCAT(NEWTOY(netcat, USE_NETCAT_LISTEN("^tlL")"w#<1W#<1p#<1>65535s:q#<1f:"USE_NETCAT_LISTEN("[!tlL][!Lw]"), TOYFLAG_BIN)) config NETCAT bool "netcat" @@ -79,9 +81,18 @@ static void lookup_name(char *name, uint32_t *result) } // Worry about a fancy lookup later. -static void lookup_port(char *str, uint16_t *port) +static unsigned short lookup_port(char *str) { - *port = SWAP_BE16(atoi(str)); + struct servent *se; + int i = atoi(str); + + if (i>0 && i<65536) return SWAP_BE16(i); + + se = getservbyname(str, "tcp"); + i = se ? se->s_port : 0; + endservent(); + + return i; } void netcat_main(void) @@ -106,8 +117,8 @@ void netcat_main(void) else { // Setup socket sockfd = xsocket(AF_INET, SOCK_STREAM, 0); - fcntl(sockfd, F_SETFD, FD_CLOEXEC); setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR, &out1, sizeof(out1)); + address->sin_family = AF_INET; if (TT.source_address || TT.port) { address->sin_port = SWAP_BE16(TT.port); @@ -119,10 +130,10 @@ void netcat_main(void) // Dial out - if (!CFG_NETCAT_LISTEN || !(toys.optflags&(FLAG_L|FLAG_l))) { + if (!(toys.optflags&(FLAG_L|FLAG_l))) { // Figure out where to dial out to. lookup_name(*toys.optargs, (uint32_t *)&(address->sin_addr)); - lookup_port(toys.optargs[1], &(address->sin_port)); + address->sin_port = lookup_port(toys.optargs[1]); // TODO xconnect if (connect(sockfd, (struct sockaddr *)address, sizeof(*address))<0) perror_exit("connect"); @@ -149,17 +160,9 @@ void netcat_main(void) do { child = 0; - len = sizeof(*address); // gcc's insane optimizer can overwrite this in1 = out2 = accept(sockfd, (struct sockaddr *)address, &len); - if (in1<0) perror_exit("accept"); - // We can't exit this loop or the optimizer's "liveness analysis" - // combines badly with vfork() to corrupt or local variables - // (the child's call stack gets trimmed and the next function call - // stops the variables the parent tries to re-use next loop) - // So there's a bit of redundancy here - // We have a connection. Disarm timeout. set_alarm(0); @@ -173,22 +176,16 @@ void netcat_main(void) // Do we need to fork and/or redirect for exec? - if (toys.optflags&FLAG_L) { - toys.stacktop = 0; - child = vfork(); - } - if (child<0) error_msg("vfork failed\n"); - else { - if (child) { - close(in1); - continue; - } - dup2(in1, 0); - dup2(in1, 1); - if (toys.optflags&FLAG_L) dup2(in1, 2); - if (in1>2) close(in1); - xexec(toys.optargs); + if (toys.optflags&FLAG_L) NOEXIT(child = XVFORK()); + if (child) { + close(in1); + continue; } + dup2(in1, 0); + dup2(in1, 1); + if (toys.optflags&FLAG_L) dup2(in1, 2); + if (in1>2) close(in1); + xexec(toys.optargs); } pollinate(in1, in2, out1, out2, TT.idle, TT.quit_delay); -- cgit v1.2.3