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Diffstat (limited to 'src/conn-tools/s6-tcpserver6.c')
-rw-r--r--src/conn-tools/s6-tcpserver6.c412
1 files changed, 412 insertions, 0 deletions
diff --git a/src/conn-tools/s6-tcpserver6.c b/src/conn-tools/s6-tcpserver6.c
new file mode 100644
index 0000000..9b27f42
--- /dev/null
+++ b/src/conn-tools/s6-tcpserver6.c
@@ -0,0 +1,412 @@
+/* ISC license. */
+
+#ifndef _BSD_SOURCE
+#define _BSD_SOURCE
+#endif
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/wait.h>
+#include <errno.h>
+#include <unistd.h>
+#include <limits.h>
+#include <grp.h>
+#include <signal.h>
+#include <skalibs/gccattributes.h>
+#include <skalibs/allreadwrite.h>
+#include <skalibs/uint16.h>
+#include <skalibs/uint.h>
+#include <skalibs/gidstuff.h>
+#include <skalibs/setgroups.h>
+#include <skalibs/bytestr.h>
+#include <skalibs/sgetopt.h>
+#include <skalibs/fmtscan.h>
+#include <skalibs/strerr2.h>
+#include <skalibs/env.h>
+#include <skalibs/djbunix.h>
+#include <skalibs/sig.h>
+#include <skalibs/selfpipe.h>
+#include <skalibs/iopause.h>
+#include <skalibs/socket.h>
+
+#define ABSOLUTE_MAXCONN 1000
+
+#define USAGE "s6-tcpserver6 [ -v verbosity ] [ -1 ] [ -c maxconn ] [ -C localmaxconn ] [ -b backlog ] [ -G gid,gid,... ] [ -g gid ] [ -u uid ] [ -U ] ip6 port prog..."
+
+typedef struct ipnum_s ipnum_t, *ipnum_t_ref ;
+struct ipnum_s
+{
+ char ip[16] ;
+ unsigned int num ;
+} ;
+#define IPNUM_ZERO { "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0", 0 }
+
+static unsigned int maxconn = 40 ;
+static unsigned int localmaxconn = 40 ;
+static unsigned int verbosity = 1 ;
+static int cont = 1 ;
+static ipnum_t_ref pidip = 0 ;
+static unsigned int numconn = 0 ;
+static ipnum_t_ref ipnum = 0 ;
+static unsigned int iplen = 0 ;
+
+static char fmtmaxconn[UINT_FMT+1] = "/" ;
+static char fmtlocalmaxconn[UINT_FMT+1] = "/" ;
+
+
+ /* Utility functions */
+
+static inline void dieusage ()
+{
+ strerr_dieusage(100, USAGE) ;
+}
+
+static inline void X (void)
+{
+ strerr_dief1x(101, "internal inconsistency. Please submit a bug-report.") ;
+}
+
+
+ /* Lookup primitives */
+
+static unsigned int lookup_pid (unsigned int pid)
+{
+ register unsigned int i = 0 ;
+ for (; i < numconn ; i++) if (pid == pidip[i].num) break ;
+ return i ;
+}
+
+static unsigned int lookup_ip (char const *ip)
+{
+ register unsigned int i = 0 ;
+ for (; i < iplen ; i++) if (!byte_diff(ip, 16, ipnum[i].ip)) break ;
+ return i ;
+}
+
+
+ /* Logging */
+
+static void log_start (char const *ip, uint16 port)
+{
+ char fmtip[IP6_FMT] ;
+ char fmtport[UINT16_FMT] ;
+ fmtip[ip6_fmt(fmtip, ip)] = 0 ;
+ fmtport[uint16_fmt(fmtport, port)] = 0 ;
+ strerr_warni4x("starting - listening on ", fmtip, " port ", fmtport) ;
+}
+
+static inline void log_exit (void)
+{
+ strerr_warni1x("exiting") ;
+}
+
+static void log_status (void)
+{
+ char fmt[UINT_FMT] ;
+ fmt[uint_fmt(fmt, numconn)] = 0 ;
+ strerr_warni3x("status: ", fmt, fmtmaxconn) ;
+}
+
+static void log_deny (char const *ip, uint16 port, unsigned int num)
+{
+ char fmtip[IP6_FMT] ;
+ char fmtport[UINT16_FMT] ;
+ char fmtnum[UINT_FMT] ;
+ fmtip[ip6_fmt(fmtip, ip)] = 0 ;
+ fmtport[uint16_fmt(fmtport, port)] = 0 ;
+ fmtnum[uint_fmt(fmtnum, num)] = 0 ;
+ strerr_warni7sys("deny ", fmtip, " port ", fmtport, " count ", fmtnum, fmtlocalmaxconn) ;
+}
+
+static void log_accept (unsigned int pid, char const *ip, uint16 port, unsigned int num)
+{
+ char fmtipport[IP6_FMT + UINT16_FMT + 6] ;
+ char fmtpid[UINT_FMT] ;
+ char fmtnum[UINT_FMT] ;
+ register unsigned int n ;
+ n = ip6_fmt(fmtipport, ip) ;
+ byte_copy(fmtipport + n, 6, " port ") ; n += 6 ;
+ n += uint16_fmt(fmtipport + n, port) ;
+ fmtipport[n] = 0 ;
+ fmtnum[uint_fmt(fmtnum, num)] = 0 ;
+ fmtpid[uint_fmt(fmtpid, pid)] = 0 ;
+ strerr_warni7x("allow ", fmtipport, " pid ", fmtpid, " count ", fmtnum, fmtlocalmaxconn) ;
+}
+
+static void log_close (unsigned int pid, char const *ip, int w)
+{
+ char fmtpid[UINT_FMT] ;
+ char fmtip[IP6_FMT] = "?" ;
+ char fmtw[UINT_FMT] ;
+ fmtpid[uint_fmt(fmtpid, pid)] = 0 ;
+ fmtip[ip6_fmt(fmtip, ip)] = 0 ;
+ fmtw[uint_fmt(fmtw, WIFSIGNALED(w) ? WTERMSIG(w) : WEXITSTATUS(w))] = 0 ;
+ strerr_warni6x("end pid ", fmtpid, " ip ", fmtip, WIFSIGNALED(w) ? " signal " : " exitcode ", fmtw) ;
+}
+
+
+ /* Signal handling */
+
+static void killthem (int sig)
+{
+ register unsigned int i = 0 ;
+ for (; i < numconn ; i++) kill(pidip[i].num, sig) ;
+}
+
+static void wait_children (void)
+{
+ for (;;)
+ {
+ unsigned int i ;
+ int w ;
+ register int pid = wait_nohang(&w) ;
+ if (pid < 0)
+ if (errno != ECHILD) strerr_diefu1sys(111, "wait_nohang") ;
+ else break ;
+ else if (!pid) break ;
+ i = lookup_pid(pid) ;
+ if (i < numconn) /* it's one of ours ! */
+ {
+ register unsigned int j = lookup_ip(pidip[i].ip) ;
+ if (j >= iplen) X() ;
+ if (!--ipnum[j].num) ipnum[j] = ipnum[--iplen] ;
+ --numconn ;
+ if (verbosity >= 2)
+ {
+ log_close(pid, pidip[i].ip, w) ;
+ log_status() ;
+ }
+ pidip[i] = pidip[numconn] ;
+ }
+ }
+}
+
+static void handle_signals (void)
+{
+ for (;;) switch (selfpipe_read())
+ {
+ case -1 : strerr_diefu1sys(111, "read selfpipe") ;
+ case 0 : return ;
+ case SIGCHLD : wait_children() ; break ;
+ case SIGTERM :
+ {
+ if (verbosity >= 2)
+ strerr_warni3x("received ", "SIGTERM,", " quitting") ;
+ cont = 0 ;
+ break ;
+ }
+ case SIGHUP :
+ {
+ if (verbosity >= 2)
+ strerr_warni5x("received ", "SIGHUP,", " sending ", "SIGTERM+SIGCONT", " to all connections") ;
+ killthem(SIGTERM) ;
+ killthem(SIGCONT) ;
+ break ;
+ }
+ case SIGQUIT :
+ {
+ if (verbosity >= 2)
+ strerr_warni6x("received ", "SIGQUIT,", " sending ", "SIGTERM+SIGCONT", " to all connections", " and quitting") ;
+ cont = 0 ;
+ killthem(SIGTERM) ;
+ killthem(SIGCONT) ;
+ break ;
+ }
+ case SIGABRT :
+ {
+ if (verbosity >= 2)
+ strerr_warni6x("received ", "SIGABRT,", " sending ", "SIGKILL", " to all connections", " and quitting") ;
+ cont = 0 ;
+ killthem(SIGKILL) ;
+ break ;
+ }
+ default : X() ;
+ }
+}
+
+
+ /* New connection handling */
+
+static void run_child (int, char const *, uint16, unsigned int, char const *const *, char const *const *) gccattr_noreturn ;
+static void run_child (int s, char const *ip, uint16 port, unsigned int num, char const *const *argv, char const *const *envp)
+{
+ char fmt[98] ;
+ unsigned int n = 0 ;
+ PROG = "s6-tcpserver6 (child)" ;
+ if ((fd_move(0, s) < 0) || (fd_copy(1, 0) < 0))
+ strerr_diefu1sys(111, "move fds") ;
+ byte_copy(fmt+n, 24, "PROTO=TCP\0TCPREMOTEIP=") ; n += 22 ;
+ n += ip6_fmt(fmt+n, ip) ; fmt[n++] = 0 ;
+ byte_copy(fmt+n, 14, "TCPREMOTEPORT=") ; n += 14 ;
+ n += uint16_fmt(fmt+n, port) ; fmt[n++] = 0 ;
+ byte_copy(fmt+n, 11, "TCPCONNNUM=") ; n += 11 ;
+ n += uint_fmt(fmt+n, num) ; fmt[n++] = 0 ;
+ pathexec_r(argv, envp, env_len(envp), fmt, n) ;
+ strerr_dieexec(111, argv[0]) ;
+}
+
+static void new_connection (int s, char const *ip, uint16 port, char const *const *argv, char const *const *envp)
+{
+ unsigned int i = lookup_ip(ip) ;
+ unsigned int num = (i < iplen) ? ipnum[i].num : 0 ;
+ register int pid ;
+ if (num >= localmaxconn)
+ {
+ log_deny(ip, port, num) ;
+ return ;
+ }
+ pid = fork() ;
+ if (pid < 0)
+ {
+ if (verbosity) strerr_warnwu1sys("fork") ;
+ return ;
+ }
+ else if (!pid)
+ {
+ selfpipe_finish() ;
+ run_child(s, ip, port, num+1, argv, envp) ;
+ }
+
+ if (i < iplen) ipnum[i].num = num + 1 ;
+ else
+ {
+ byte_copy(ipnum[iplen].ip, 16, ip) ;
+ ipnum[iplen++].num = 1 ;
+ }
+ pidip[numconn].num = pid ;
+ byte_copy(pidip[numconn++].ip, 16, ip) ;
+ if (verbosity >= 2)
+ {
+ log_accept(pid, ip, port, ipnum[i].num) ;
+ log_status() ;
+ }
+}
+
+
+int main (int argc, char const *const *argv, char const *const *envp)
+{
+ iopause_fd x[2] = { { -1, IOPAUSE_READ, 0 }, { -1, IOPAUSE_READ | IOPAUSE_EXCEPT, 0 } } ;
+ PROG = "s6-tcpserver6" ;
+ {
+ subgetopt_t l = SUBGETOPT_ZERO ;
+ unsigned int uid = 0, gid = 0 ;
+ gid_t gids[NGROUPS_MAX] ;
+ unsigned int gidn = 0 ;
+ unsigned int backlog = 20 ;
+ char ip[16] ;
+ int flag1 = 0 ;
+ uint16 port ;
+ for (;;)
+ {
+ register int opt = subgetopt_r(argc, argv, "1Uc:C:b:u:g:G:v:", &l) ;
+ if (opt == -1) break ;
+ switch (opt)
+ {
+ case '1' : flag1 = 1 ; break ;
+ case 'c' : if (!uint0_scan(l.arg, &maxconn)) dieusage() ; break ;
+ case 'C' : if (!uint0_scan(l.arg, &localmaxconn)) dieusage() ; break ;
+ case 'b' : if (!uint0_scan(l.arg, &backlog)) dieusage() ; break ;
+ case 'u' : if (!uint0_scan(l.arg, &uid)) dieusage() ; break ;
+ case 'g' : if (!uint0_scan(l.arg, &gid)) dieusage() ; break ;
+ case 'G' : if (!gid_scanlist(gids, NGROUPS_MAX, l.arg, &gidn)) dieusage() ; break ;
+ case 'v' : if (!uint0_scan(l.arg, &verbosity)) dieusage() ; break ;
+ case 'U' :
+ {
+ char const *x = env_get2(envp, "UID") ;
+ if (!x) strerr_dienotset(100, "UID") ;
+ if (!uint0_scan(x, &uid)) strerr_dieinvalid(100, "UID") ;
+ x = env_get2(envp, "GID") ;
+ if (!x) strerr_dienotset(100, "GID") ;
+ if (!uint0_scan(x, &gid)) strerr_dieinvalid(100, "GID") ;
+ x = env_get2(envp, "GIDLIST") ;
+ if (!x) strerr_dienotset(100, "GIDLIST") ;
+ if (!gid_scanlist(gids, NGROUPS_MAX, x, &gidn) && *x)
+ strerr_dieinvalid(100, "GIDLIST") ;
+ break ;
+ }
+ default : dieusage() ;
+ }
+ }
+ argc -= l.ind ; argv += l.ind ;
+ if (argc < 3) dieusage() ;
+ if (!ip6_scan(argv[0], ip) || !uint160_scan(argv[1], &port)) dieusage() ;
+ fd_close(0) ;
+ if (!flag1) fd_close(1) ;
+ if (!maxconn) maxconn = 1 ;
+ if (maxconn > ABSOLUTE_MAXCONN) maxconn = ABSOLUTE_MAXCONN ;
+ if (localmaxconn > maxconn) localmaxconn = maxconn ;
+ x[1].fd = socket_tcp6() ;
+ if ((x[1].fd == -1) || (coe(x[1].fd) == -1))
+ strerr_diefu1sys(111, "create socket") ;
+ if (socket_bind6_reuse(x[1].fd, ip, port) < 0)
+ strerr_diefu2sys(111, "bind to ", argv[0]) ;
+ if (socket_listen(x[1].fd, backlog) == -1)
+ strerr_diefu1sys(111, "listen") ;
+ if (gidn && (setgroups(gidn, gids) < 0)) strerr_diefu1sys(111, "setgroups") ;
+ if (gid && (setgid(gid) < 0)) strerr_diefu1sys(111, "drop gid") ;
+ if (uid && (setuid(uid) < 0)) strerr_diefu1sys(111, "drop uid") ;
+
+ x[0].fd = selfpipe_init() ;
+ if (x[0].fd == -1) strerr_diefu1sys(111, "create selfpipe") ;
+ if (sig_ignore(SIGPIPE) < 0) strerr_diefu1sys(111, "ignore SIGPIPE") ;
+ {
+ sigset_t set ;
+ sigemptyset(&set) ;
+ sigaddset(&set, SIGCHLD) ;
+ sigaddset(&set, SIGTERM) ;
+ sigaddset(&set, SIGHUP) ;
+ sigaddset(&set, SIGQUIT) ;
+ sigaddset(&set, SIGABRT) ;
+ if (selfpipe_trapset(&set) < 0) strerr_diefu1sys(111, "trap signals") ;
+ }
+ if (flag1)
+ {
+ char fmt[UINT16_FMT] ;
+ unsigned int n = uint16_fmt(fmt, port) ;
+ fmt[n++] = '\n' ;
+ if (allwrite(1, fmt, n) < n) strerr_diefu1sys(111, "write to stdout") ;
+ fd_close(1) ;
+ }
+ fmtlocalmaxconn[1+uint_fmt(fmtlocalmaxconn+1, localmaxconn)] = 0 ;
+ if (verbosity >= 2)
+ {
+ fmtmaxconn[1+uint_fmt(fmtmaxconn+1, maxconn)] = 0 ;
+ log_start(ip, port) ;
+ log_status() ;
+ }
+ }
+
+ {
+ ipnum_t inyostack[maxconn<<1] ;
+ pidip = inyostack ; ipnum = inyostack + maxconn ;
+ while (cont)
+ {
+ if (iopause(x, 1 + (numconn < maxconn), 0, 0) == -1)
+ strerr_diefu1sys(111, "iopause") ;
+
+ if (x[0].revents & IOPAUSE_EXCEPT) strerr_dief1x(111, "trouble with selfpipe") ;
+ if (x[0].revents & IOPAUSE_READ) handle_signals() ;
+ if (numconn < maxconn)
+ {
+ if (x[1].revents & IOPAUSE_EXCEPT) strerr_dief1x(111, "trouble with socket") ;
+ if (x[1].revents & IOPAUSE_READ)
+ {
+ char ip[16] ;
+ uint16 port ;
+ register int fd = socket_accept6(x[1].fd, ip, &port) ;
+ if (fd < 0)
+ {
+ if (verbosity) strerr_warnwu1sys("accept") ;
+ }
+ else
+ {
+ new_connection(fd, ip, port, argv+2, envp) ;
+ fd_close(fd) ;
+ }
+ }
+ }
+ }
+ }
+ if (verbosity >= 2) log_exit() ;
+ return 0 ;
+}