446 lines
8.6 KiB
C
446 lines
8.6 KiB
C
/*
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in.rshd.c
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*/
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/*
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main channel:
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back channel\0
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remuser\0
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locuser\0
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command\0
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data
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back channel:
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signal\0
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*/
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#include <sys/types.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <limits.h>
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#include <pwd.h>
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#include <grp.h>
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#include <signal.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include <sys/ioctl.h>
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#include <net/gen/in.h>
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#include <net/gen/inet.h>
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#include <netdb.h>
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#include <net/gen/socket.h>
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#include <net/gen/tcp.h>
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#include <net/gen/tcp_io.h>
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#include <net/hton.h>
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#include <net/netlib.h>
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#define DEBUG 0
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#if DEBUG
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#define where() fprintf(stderr, "%s, %d: ", __FILE__, __LINE__)
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#endif
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char cmdbuf[_POSIX_ARG_MAX+1], locuser[16], remuser[16];
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extern char **environ;
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char username[20]="USER=";
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char homedir[64]="HOME=";
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char shell[64]="SHELL=";
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char tz[1024]="TZ=";
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char *envinit[]= {homedir, shell, username, tz, "PATH=:/bin:/usr/bin", 0};
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char *prog_name;
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char buffer[PIPE_BUF];
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#if __STDC__
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#define PROTO(func, args) func args
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#else
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#define PROTO(func, args) func ()
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#endif
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PROTO (int main, (int argc, char *argv[]));
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PROTO (void getstr, (char*buf, int cnt, char *err));
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PROTO (void close_on_exec, (int fd));
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int main(argc, argv)
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int argc;
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char *argv[];
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{
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int result, result1;
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nwio_tcpconf_t tcpconf, err_tcpconf;
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nwio_tcpcl_t tcpconnopt;
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nwio_tcpatt_t tcpattachopt;
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tcpport_t tcpport;
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tcpport_t err_port;
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int err_fd, pds[2];
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pid_t pid, pid1, new_pg;
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#if USEATTACH
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int err2_fd;
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#endif
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struct passwd *pwent;
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char *cp, *buff_ptr, *TZ;
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char sig;
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prog_name= argv[0];
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if (argc != 1)
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{
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fprintf(stderr, "%s: wrong number of arguments (%d)\n",
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prog_name, argc);
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exit(1);
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}
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signal(SIGINT, SIG_DFL);
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signal(SIGQUIT, SIG_DFL);
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signal(SIGTERM, SIG_DFL);
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#if DEBUG
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{ where(); fprintf(stderr, "\n"); }
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#endif
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result= ioctl (0, NWIOGTCPCONF, &tcpconf);
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if (result<0)
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{
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fprintf(stderr, "%s: ioctl(NWIOGTCPCONF)= %d : %s\n",
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prog_name, errno, strerror(errno));
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exit(1);
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}
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#if DEBUG
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{ where(); fprintf(stderr, "\n"); }
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#endif
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tcpport= ntohs(tcpconf.nwtc_remport);
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if (tcpport >= TCPPORT_RESERVED || tcpport < TCPPORT_RESERVED/2)
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{
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printf("\1%s: unprotected port (%d)\n", prog_name, tcpport);
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exit(1);
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}
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alarm(60);
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err_port= 0;
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for (;;)
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{
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char c;
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result= read(0, &c, 1);
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if (result <0)
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{
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fprintf(stderr, "%s: read= %d : %s\n", prog_name,
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errno, strerror(errno));
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}
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if (result<1)
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exit(1);
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if (c == 0)
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break;
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err_port= err_port*10 + c - '0';
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}
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alarm(0);
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if (err_port != 0)
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{
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int n, pid, lport;
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pid= getpid();
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lport= 1;
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do {
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lport= (lport << 1) | (pid & 1);
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pid >>= 1;
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} while (lport < TCPPORT_RESERVED/2);
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n= TCPPORT_RESERVED/2;
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do
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{
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if (--lport < TCPPORT_RESERVED/2)
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lport= TCPPORT_RESERVED-1;
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err_fd= open ("/dev/tcp", O_RDWR);
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if (err_fd<0)
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{
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fprintf(stderr, "%s: open= %d : %s\n",
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prog_name, errno, strerror(errno));
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exit(1);
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}
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close_on_exec(err_fd);
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err_tcpconf.nwtc_flags= NWTC_LP_SET | NWTC_SET_RA |
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NWTC_SET_RP | NWTC_EXCL;
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err_tcpconf.nwtc_locport= htons(lport);
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err_tcpconf.nwtc_remport= htons(err_port);
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err_tcpconf.nwtc_remaddr= tcpconf.nwtc_remaddr;
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#if DEBUG
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{ where(); fprintf(stderr, "\n"); }
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#endif
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result= ioctl (err_fd, NWIOSTCPCONF, &err_tcpconf);
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if (result == 0) break;
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if (errno != EADDRINUSE)
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{
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fprintf(stderr,
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"%s: ioctl(NWIOSTCPCONF)= %d : %s\n",
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prog_name, errno, strerror(errno));
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exit(1);
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}
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close(err_fd);
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} while (--n > 0);
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if (n == 0)
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{
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printf("\1can't get stderr port\n");
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exit(1);
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}
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err_tcpconf.nwtc_flags= NWTC_SHARED;
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#if DEBUG
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{ where(); fprintf(stderr, "\n"); }
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#endif
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result= ioctl (err_fd, NWIOSTCPCONF, &err_tcpconf);
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if (result<0)
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{
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fprintf(stderr,
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"%s: ioctl(NWIOSTCPCONF)= %d : %s\n",
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prog_name, errno, strerror(errno));
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exit(1);
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}
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#if DEBUG
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{ where(); fprintf(stderr, "\n"); }
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#endif
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tcpconnopt.nwtcl_flags= 0;
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n= 20;
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for (;;)
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{
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#if DEBUG
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{ where(); fprintf(stderr, "\n"); }
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#endif
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result= ioctl (err_fd, NWIOTCPCONN, &tcpconnopt);
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if (result == 0) break;
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if (errno != EAGAIN && errno != ECONNREFUSED)
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{
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fprintf(stderr,
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"%s: ioctl(NWIOTCPCONN)= %d : %s\n",
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prog_name, errno, strerror(errno));
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exit(1);
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}
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if (--n == 0) break;
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sleep(1);
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#if DEBUG
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{ where(); fprintf(stderr, "\n"); }
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#endif
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}
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#if USEATTACH
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err2_fd= open ("/dev/tcp", O_RDWR);
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close_on_exec(err2_fd);
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if (err2_fd<0)
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{
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fprintf(stderr, "%s: open= %d : %s\n", errno,
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prog_name, strerror(errno));
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exit(1);
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}
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#if DEBUG
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{ where(); fprintf(stderr, "\n"); }
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#endif
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result= ioctl (err2_fd, NWIOSTCPCONF, &err_tcpconf);
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if (result<0)
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{
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fprintf(stderr, "%s: ioctl(NWIOSTCPCONF)= %d : %s\n",
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prog_name, errno, strerror(errno));
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exit(1);
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}
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#if DEBUG
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{ where(); fprintf(stderr, "\n"); }
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#endif
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tcpattachopt.nwta_flags= 0;
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#if DEBUG
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{ where(); fprintf(stderr, "\n"); }
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#endif
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result= ioctl (err2_fd, NWIOTCPATTACH, &tcpattachopt);
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if (result<0)
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{
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fprintf(stderr, "%s: ioctl(NWIOTCPATTACH)= %d : %s\n",
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prog_name, errno, strerror(errno));
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exit(1);
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}
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#if DEBUG
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{ where(); fprintf(stderr, "\n"); }
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#endif
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#endif
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}
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getstr(remuser, sizeof(remuser), "remuser");
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getstr(locuser, sizeof(locuser), "locuser");
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getstr(cmdbuf, sizeof(cmdbuf), "cmdbuf");
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setpwent();
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pwent= getpwnam(locuser);
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if (!pwent)
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{
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printf("\1Login incorrect.\n");
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exit(1);
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}
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endpwent();
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if (chdir(pwent->pw_dir) < 0)
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{
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chdir("/");
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}
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#if DEBUG
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{ where(); fprintf(stderr, "calling iruserok(%s, %d, %s, %s)\n",
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inet_ntoa(tcpconf.nwtc_remaddr), 0, remuser, locuser); }
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#endif
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if (iruserok(tcpconf.nwtc_remaddr, 0, remuser, locuser) < 0)
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{
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printf("\1Permission denied.\n");
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exit(1);
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}
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if (err_port)
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{
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/* Let's go to a different process group. */
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new_pg= setsid();
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pid= fork();
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if (pid<0)
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{
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if (errno != EAGAIN)
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{
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fprintf(stderr, "%s: fork()= %d : %s\n",
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prog_name, errno, strerror(errno));
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}
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printf("\1Try again.\n");
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exit(1);
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}
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if (pid)
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{
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close(0); /* stdin */
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close(1); /* stdout */
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#if USEATTACH
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close(err_fd); /* stderr for shell */
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#endif
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dup2(2,0);
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dup2(2,1);
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for (;;)
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{
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#if !USEATTACH
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if (read(err_fd, &sig, 1) <= 0)
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#else
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if (read(err2_fd, &sig, 1) <= 0)
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#endif
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{
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#if 0
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printf("read failed: %d\n", errno);
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#endif
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exit(0);
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}
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pid= 0;
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#if 0
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printf("killing %d with %d\n", -new_pg, sig);
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#endif
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kill(-new_pg, sig);
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}
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}
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#if USEATTACH
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close(err2_fd); /* signal channel for parent */
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#endif
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result= pipe(pds);
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if (result<0)
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{
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printf("\1Can't make pipe\n");
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kill(getppid(), SIGTERM);
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exit(1);
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}
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pid1= fork();
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if (pid1<0)
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{
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if (errno != EAGAIN)
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{
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fprintf(stderr, "%s: fork()= %d : %s\n",
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prog_name, errno, strerror(errno));
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}
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printf("\1Try again.\n");
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kill(-new_pg, SIGTERM);
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exit(1);
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}
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if (pid1)
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{
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close(pds[1]); /* write side of pipe */
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for (;;)
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{
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result= read(pds[0], buffer, sizeof(buffer));
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if (result<=0)
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{
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kill(pid, SIGTERM);
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exit(0);
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}
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buff_ptr= buffer;
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while (result>0)
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{
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result1= write (err_fd, buff_ptr,
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result);
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if (result1 <= 0)
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{
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fprintf(stderr,
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"%s: write()= %d : %s\n",
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prog_name, errno,
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strerror(errno));
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kill(-new_pg, SIGTERM);
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exit(1);
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}
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result -= result1;
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}
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}
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}
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close(err_fd); /* file descriptor for error channel */
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close (pds[0]); /* read side of pipe */
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dup2(pds[1], 2);
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close (pds[1]); /* write side of pipe */
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}
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if (*pwent->pw_shell == '\0')
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pwent->pw_shell= "/bin/sh";
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#if __minix_vmd
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initgroups(pwent->pw_name, pwent->pw_gid);
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#endif
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setgid(pwent->pw_gid);
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setuid(pwent->pw_uid);
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TZ=getenv("TZ");
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environ= envinit;
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strncat(homedir, pwent->pw_dir, sizeof(homedir)-6);
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strncat(shell, pwent->pw_shell, sizeof(shell)-7);
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strncat(username, pwent->pw_name, sizeof(username)-6);
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if (TZ)
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strncat(tz, TZ, sizeof(tz)-4);
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else
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envinit[3]= NULL;
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cp= strrchr(pwent->pw_shell, '/');
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if (cp)
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cp++;
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else
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cp= pwent->pw_shell;
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if (!err_port)
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dup2(1, 2);
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write(1, "\0", 1);
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execl(pwent->pw_shell, cp, "-c", cmdbuf, 0);
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close(2);
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open("/dev/tty", O_RDWR);
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fprintf(stderr, "%s: execl(%s, %s, .., %s)= %d : %s\n", prog_name,
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pwent->pw_shell, cp, cmdbuf, errno, strerror(errno));
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kill(getppid(), SIGTERM);
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exit(1);
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}
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void getstr(buf, cnt, err)
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char *buf;
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int cnt;
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char *err;
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{
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char c;
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do
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{
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if (read(0, &c, 1) != 1)
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exit(1);
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*buf++ = c;
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if (--cnt == 0)
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{
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printf("\1%s too long", err);
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exit(1);
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}
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} while (c != 0);
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}
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void close_on_exec(fd)
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int fd;
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{
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(void) fcntl(fd, F_SETFD, fcntl(fd, F_GETFD) | FD_CLOEXEC);
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}
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