From: Denys Vlasenko Date: Fri, 7 Oct 2016 13:56:47 +0000 (+0200) Subject: tcpsvd: don't keep shared fd open if fd limit is reached. closes 9331 X-Git-Tag: 1_26_0~160 X-Git-Url: https://git.librecmc.org/?a=commitdiff_plain;h=ec1ea16337623824e3e71bb5dc0e011259664d7e;p=oweals%2Fbusybox.git tcpsvd: don't keep shared fd open if fd limit is reached. closes 9331 Also, much improved help text. function old new delta packed_usage 30652 30851 +199 tcpudpsvd_main 1782 1784 +2 Signed-off-by: Denys Vlasenko --- diff --git a/networking/tcpudp.c b/networking/tcpudp.c index fbd1f1c45..b27cf3ea9 100644 --- a/networking/tcpudp.c +++ b/networking/tcpudp.c @@ -34,37 +34,56 @@ /* with not-implemented options: */ /* //usage: "[-hpEvv] [-c N] [-C N[:MSG]] [-b N] [-u USER] [-l NAME] [-i DIR|-x CDB] [-t SEC] IP PORT PROG" */ //usage:#define tcpsvd_full_usage "\n\n" -//usage: "Create TCP socket, bind to IP:PORT and listen\n" -//usage: "for incoming connection. Run PROG for each connection.\n" -//usage: "\n IP IP to listen on, 0 = all" -//usage: "\n PORT Port to listen on" +//usage: "Create TCP socket, bind to IP:PORT and listen for incoming connections.\n" +//usage: "Run PROG for each connection.\n" +//usage: "\n IP PORT IP:PORT to listen on" //usage: "\n PROG ARGS Program to run" -//usage: "\n -l NAME Local hostname (else looks up local hostname in DNS)" //usage: "\n -u USER[:GRP] Change to user/group after bind" -//usage: "\n -c N Handle up to N connections simultaneously" -//usage: "\n -b N Allow a backlog of approximately N TCP SYNs" -//usage: "\n -C N[:MSG] Allow only up to N connections from the same IP" -//usage: "\n New connections from this IP address are closed" -//usage: "\n immediately. MSG is written to the peer before close" +//usage: "\n -c N Up to N connections simultaneously (default 30)" +//usage: "\n -b N Allow backlog of approximately N TCP SYNs (default 20)" +//usage: "\n -C N[:MSG] Allow only up to N connections from the same IP:" +//usage: "\n new connections from this IP address are closed" +//usage: "\n immediately, MSG is written to the peer before close" +//usage: "\n -E Don't set up environment" //usage: "\n -h Look up peer's hostname" -//usage: "\n -E Don't set up environment variables" +//usage: "\n -l NAME Local hostname (else look up local hostname in DNS)" //usage: "\n -v Verbose" +//usage: "\n" +//usage: "\nEnvironment if no -E:" +//usage: "\nPROTO='TCP'" +//usage: "\nTCPREMOTEADDR='ip:port'" IF_FEATURE_IPV6(" ('[ip]:port' for IPv6)") +//usage: "\nTCPLOCALADDR='ip:port'" +//usage: "\nTCPORIGDSTADDR='ip:port' of destination before firewall" +//usage: "\n Useful for REDIRECTed-to-local connections:" +//usage: "\n iptables -t nat -A PREROUTING -p tcp --dport 80 -j REDIRECT --to 8080" +//usage: "\nTCPCONCURRENCY=num_of_connects_from_this_ip" +//usage: "\nIf -h:" +//usage: "\nTCPLOCALHOST='hostname' (-l NAME is used if specified)" +//usage: "\nTCPREMOTEHOST='hostname'" + //usage: //usage:#define udpsvd_trivial_usage //usage: "[-hEv] [-c N] [-u USER] [-l NAME] IP PORT PROG" //usage:#define udpsvd_full_usage "\n\n" -//usage: "Create UDP socket, bind to IP:PORT and wait\n" -//usage: "for incoming packets. Run PROG for each packet,\n" -//usage: "redirecting all further packets with same peer ip:port to it.\n" -//usage: "\n IP IP to listen on, 0 = all" -//usage: "\n PORT Port to listen on" +//usage: "Create UDP socket, bind to IP:PORT and wait for incoming packets.\n" +//usage: "Run PROG for each packet, redirecting all further packets with same\n" +//usage: "peer ip:port to it.\n" +//usage: "\n IP PORT IP:PORT to listen on" //usage: "\n PROG ARGS Program to run" -//usage: "\n -l NAME Local hostname (else looks up local hostname in DNS)" //usage: "\n -u USER[:GRP] Change to user/group after bind" -//usage: "\n -c N Handle up to N connections simultaneously" +//usage: "\n -c N Up to N connections simultaneously (default 30)" +//usage: "\n -E Don't set up environment" //usage: "\n -h Look up peer's hostname" -//usage: "\n -E Don't set up environment variables" +//usage: "\n -l NAME Local hostname (else look up local hostname in DNS)" //usage: "\n -v Verbose" +//usage: "\n" +//usage: "\nEnvironment if no -E:" +//usage: "\nPROTO='UDP'" +//usage: "\nUDPREMOTEADDR='ip:port'" IF_FEATURE_IPV6(" ('[ip]:port' for IPv6)") +//usage: "\nUDPLOCALADDR='ip:port'" +//usage: "\nIf -h:" +//usage: "\nUDPLOCALHOST='hostname' (-l NAME is used if specified)" +//usage: "\nUDPREMOTEHOST='hostname'" #include "libbb.h" #include "common_bufsiz.h" @@ -240,7 +259,7 @@ int tcpudpsvd_main(int argc UNUSED_PARAM, char **argv) ); #else /* "+": stop on first non-option */ - opts = getopt32(argv, "+c:C:i:x:u:l:Eb:hpt:v", + opts = getopt32(argv, "+c:+C:i:x:u:l:Eb:hpt:v", &cmax, &str_C, &instructs, &instructs, &user, &preset_local_hostname, &backlog, &str_t, &verbose ); @@ -349,16 +368,20 @@ int tcpudpsvd_main(int argc UNUSED_PARAM, char **argv) again: hccp = NULL; + again1: + close(0); + /* It's important to close(0) _before_ wait loop: + * fd#0 can be a shared connection fd. + * If kept open by us, peer can't detect PROG closing it. + */ while (cnum >= cmax) wait_for_any_sig(); /* expecting SIGCHLD */ - /* Accept a connection to fd #0 */ - again1: - close(0); again2: sig_unblock(SIGCHLD); local.len = remote.len = sa_len; if (tcp) { + /* Accept a connection to fd #0 */ conn = accept(sock, &remote.u.sa, &remote.len); } else { /* In case recv_from_to won't be able to recover local addr.