mirror of https://github.com/sheumann/hush.git
463 lines
10 KiB
C
463 lines
10 KiB
C
#include "internal.h"
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#include <stdio.h>
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#include <stdlib.h>
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#include <stdarg.h>
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#include <unistd.h>
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#include <errno.h>
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#include <signal.h>
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#include <termios.h>
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#include <sys/types.h>
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#include <sys/fcntl.h>
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#include <sys/wait.h>
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#include <string.h>
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#include <sys/mount.h>
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#include <sys/reboot.h>
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#include <sys/kdaemon.h>
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#include <sys/sysmacros.h>
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#include <linux/serial.h> /* for serial_struct */
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#include <sys/vt.h> /* for vt_stat */
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#include <sys/ioctl.h>
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static const char init_usage[] = "Used internally by the system.";
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static char console[16] = "";
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static const char* default_console = "/dev/tty2";
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static char* first_terminal = NULL;
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static const char* second_terminal = "/dev/tty2";
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static const char* log = "/dev/tty3";
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static char* term_ptr = NULL;
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static void
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message(const char* terminal, const char * pattern, ...)
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{
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int fd;
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FILE * con = 0;
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va_list arguments;
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/*
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* Open the console device each time a message is printed. If the user
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* has switched consoles, the open will get the new console. If we kept
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* the console open, we'd always print to the same one.
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*/
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if ( !terminal
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|| ((fd = open(terminal, O_WRONLY|O_NOCTTY)) < 0)
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|| ((con = fdopen(fd, "w")) == NULL) )
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return;
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va_start(arguments, pattern);
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vfprintf(con, pattern, arguments);
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va_end(arguments);
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fclose(con);
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}
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static int
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waitfor(int pid)
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{
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int status;
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int wpid;
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message(log, "Waiting for process %d.\n", pid);
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while ( (wpid = wait(&status)) != pid ) {
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if ( wpid > 0 ) {
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message(
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log
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,"pid %d exited, status=%x.\n"
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,wpid
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,status);
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}
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}
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return wpid;
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}
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static int
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run(const char* program, const char* const* arguments,
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const char* terminal, int get_enter)
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{
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static const char control_characters[] = {
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'\003',
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'\034',
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'\177',
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'\025',
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'\004',
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'\0',
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'\1',
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'\0',
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'\021',
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'\023',
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'\032',
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'\0',
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'\022',
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'\017',
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'\027',
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'\026',
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'\0'
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};
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static char * environment[] = {
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"HOME=/",
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"PATH=/bin:/sbin:/usr/bin:/usr/sbin",
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"SHELL=/bin/sh",
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0,
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"USER=root",
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0
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};
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static const char press_enter[] =
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"\nPlease press Enter to activate this console. ";
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int pid;
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environment[3]=term_ptr;
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pid = fork();
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if ( pid == 0 ) {
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struct termios t;
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const char * const * arg;
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close(0);
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close(1);
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close(2);
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setsid();
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open(terminal, O_RDWR);
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dup(0);
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dup(0);
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tcsetpgrp(0, getpgrp());
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tcgetattr(0, &t);
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memcpy(t.c_cc, control_characters, sizeof(control_characters));
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t.c_line = 0;
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t.c_iflag = ICRNL|IXON|IXOFF;
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t.c_oflag = OPOST|ONLCR;
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t.c_lflag = ISIG|ICANON|ECHO|ECHOE|ECHOK|ECHOCTL|ECHOKE|IEXTEN;
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tcsetattr(0, TCSANOW, &t);
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if ( get_enter ) {
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/*
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* Save memory by not exec-ing anything large (like a shell)
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* before the user wants it. This is critical if swap is not
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* enabled and the system has low memory. Generally this will
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* be run on the second virtual console, and the first will
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* be allowed to start a shell or whatever an init script
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* specifies.
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*/
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char c;
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write(1, press_enter, sizeof(press_enter) - 1);
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read(0, &c, 1);
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}
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message(log, "Executing ");
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arg = arguments;
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while ( *arg != 0 )
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message(log, "%s ", *arg++);
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message(log, "\n");
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execve(program, (char * *)arguments, (char * *)environment);
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message(log, "%s: could not execute: %s.\r\n", program, strerror(errno));
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exit(-1);
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}
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return pid;
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}
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static int
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mem_total()
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{
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char s[80];
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char *p;
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FILE *f;
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const char pattern[]="MemTotal:";
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f=fopen("/proc/meminfo","r");
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while (NULL != fgets(s,79,f)) {
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p=strstr(s, pattern);
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if (NULL != p) {
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fclose(f);
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return(atoi(p+strlen(pattern)));
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}
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}
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return -1;
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}
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static void
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set_free_pages()
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{
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char s[80];
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FILE *f;
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f=fopen("/proc/sys/vm/freepages","r");
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fgets(s,79,f);
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if (atoi(s) < 32) {
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fclose(f);
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f=fopen("/proc/sys/vm/freepages","w");
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fprintf(f,"30\t40\t50\n");
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printf("\nIncreased /proc/sys/vm/freepages values to 30/40/50\n");
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}
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fclose(f);
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}
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static int
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get_kernel_revision()
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{
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FILE *f;
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int major=0, minor=0, patch=0;
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f = fopen("/proc/sys/kernel/osrelease","r");
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fscanf(f,"%d.%d.%d",&major,&minor,&patch);
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fclose(f);
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return major*65536 + minor*256 + patch;
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}
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static void
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shutdown_system(void)
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{
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static const char * const umount_args[] = {"/bin/umount", "-a", "-n", 0};
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static const char * const swapoff_args[] = {"/bin/swapoff", "-a", 0};
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message(console, "The system is going down NOW !!");
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sync();
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/* Allow Ctrl-Alt-Del to reboot system. */
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reboot(RB_ENABLE_CAD);
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/* Send signals to every process _except_ pid 1 */
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message(console, "Sending SIGHUP to all processes.\r\n");
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kill(-1, SIGHUP);
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sleep(2);
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sync();
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message(console, "Sending SIGKILL to all processes.\r\n");
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kill(-1, SIGKILL);
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sleep(1);
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waitfor(run("/bin/swapoff", swapoff_args, console, 0));
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waitfor(run("/bin/umount", umount_args, console, 0));
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sync();
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if (get_kernel_revision() <= 2*65536+2*256+11) {
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/* Removed bdflush call, kupdate in kernels >2.2.11 */
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bdflush(1, 0);
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sync();
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}
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}
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static void
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halt_signal(int sig)
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{
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shutdown_system();
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message(console, "The system is halted. Press CTRL-ALT-DEL or turn off power\r\n");
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reboot( RB_HALT_SYSTEM);
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exit(0);
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}
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static void
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reboot_signal(int sig)
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{
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shutdown_system();
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message(console, "Please stand by while rebooting the system.\r\n");
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reboot( RB_AUTOBOOT);
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exit(0);
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}
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static void
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configure_terminals( int serial_cons, int single_user_mode )
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{
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char *tty;
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struct serial_struct sr;
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struct vt_stat vt;
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switch (serial_cons) {
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case -1:
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/* 2.2 kernels:
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* identify the real console backend and try to make use of it */
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if (ioctl(0,TIOCGSERIAL,&sr) == 0) {
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sprintf( console, "/dev/ttyS%d", sr.line );
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serial_cons = sr.line+1;
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}
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else if (ioctl(0, VT_GETSTATE, &vt) == 0) {
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sprintf( console, "/dev/tty%d", vt.v_active );
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serial_cons = 0;
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}
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else {
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/* unknown backend: fallback to /dev/console */
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strcpy( console, "/dev/console" );
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serial_cons = 0;
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}
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break;
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case 1:
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strcpy( console, "/dev/cua0" );
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break;
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case 2:
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strcpy( console, "/dev/cua1" );
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break;
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default:
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tty = ttyname(0);
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if (tty) {
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strcpy( console, tty );
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if (!strncmp( tty, "/dev/cua", 8 ))
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serial_cons=1;
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}
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else
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/* falls back to /dev/tty1 if an error occurs */
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strcpy( console, default_console );
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}
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if (!first_terminal)
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first_terminal = console;
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#if defined (__sparc__)
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if (serial_cons > 0 && !strncmp(term_ptr,"TERM=linux",10))
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term_ptr = "TERM=vt100";
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#endif
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if (serial_cons) {
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/* disable other but the first terminal:
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* VT is not initialized anymore on 2.2 kernel when booting from
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* serial console, therefore modprobe is flooding the display with
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* "can't locate module char-major-4" messages. */
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log = 0;
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second_terminal = 0;
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}
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}
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extern int
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init_main(int argc, char * * argv)
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{
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const char * rc_arguments[100];
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const char * arguments[100];
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int run_rc = TRUE;
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int j;
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int pid1 = 0;
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int pid2 = 0;
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struct stat statbuf;
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const char * tty_commands[3] = { "etc/init.d/rcS", "bin/sh"};
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int serial_console = 0;
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int retval;
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/*
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* If I am started as /linuxrc instead of /sbin/init, I don't have the
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* environment that init expects. I can't fix the signal behavior. Try
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* to divorce from the controlling terminal with setsid(). This won't work
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* if I am the process group leader.
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*/
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setsid();
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signal(SIGUSR1, halt_signal);
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signal(SIGUSR2, reboot_signal);
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signal(SIGINT, reboot_signal);
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signal(SIGTERM, reboot_signal);
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reboot(RB_DISABLE_CAD);
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message(log, "%s: started. ", argv[0]);
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for ( j = 1; j < argc; j++ ) {
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if ( strcmp(argv[j], "single") == 0 ) {
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run_rc = FALSE;
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tty_commands[0] = "bin/sh";
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tty_commands[1] = 0;
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}
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}
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for ( j = 0; __environ[j] != 0; j++ ) {
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if ( strncmp(__environ[j], "tty", 3) == 0
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&& __environ[j][3] >= '1'
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&& __environ[j][3] <= '2'
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&& __environ[j][4] == '=' ) {
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const char * s = &__environ[j][5];
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if ( *s == 0 || strcmp(s, "off") == 0 )
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s = 0;
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tty_commands[__environ[j][3] - '1'] = s;
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}
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/* Should catch the syntax of Sparc kernel console setting. */
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/* The kernel does not recognize a serial console when getting*/
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/* console=/dev/ttySX !! */
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else if ( strcmp(__environ[j], "console=ttya") == 0 ) {
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serial_console=1;
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}
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else if ( strcmp(__environ[j], "console=ttyb") == 0 ) {
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serial_console=2;
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}
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/* standard console settings */
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else if ( strncmp(__environ[j], "console=", 8) == 0 ) {
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first_terminal=&(__environ[j][8]);
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}
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else if ( strncmp(__environ[j], "TERM=", 5) == 0) {
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term_ptr=__environ[j];
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}
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}
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printf("mounting /proc ...\n");
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if (mount("/proc","/proc","proc",0,0)) {
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perror("mounting /proc failed\n");
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}
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printf("\tdone.\n");
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if (get_kernel_revision() >= 2*65536+1*256+71) {
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/* if >= 2.1.71 kernel, /dev/console is not a symlink anymore:
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* use it as primary console */
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serial_console=-1;
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}
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/* Make sure /etc/init.d/rc exists */
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retval= stat(tty_commands[0],&statbuf);
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if (retval)
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run_rc = FALSE;
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configure_terminals( serial_console, run_rc);
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set_free_pages();
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/* not enough memory to do anything useful*/
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if (mem_total() < 2000) {
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retval= stat("/etc/fstab",&statbuf);
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if (retval) {
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printf("You do not have enough RAM, sorry.\n");
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while (1) { sleep(1);}
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} else {
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/* Try to turn on swap */
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static const char * const swapon_args[] = {"/bin/swapon", "-a", 0};
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waitfor(run("/bin/swapon", swapon_args, console, 0));
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if (mem_total() < 2000) {
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printf("You do not have enough RAM, sorry.\n");
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while (1) { sleep(1);}
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}
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}
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}
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/*
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* Don't modify **argv directly, it would show up in the "ps" display.
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* I don't want "init" to look like "rc".
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*/
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rc_arguments[0] = tty_commands[0];
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for ( j = 1; j < argc; j++ ) {
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rc_arguments[j] = argv[j];
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}
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rc_arguments[j] = 0;
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arguments[0] = "-sh";
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arguments[1] = 0;
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/* Ok, now launch the rc script /etc/init.d/rcS and prepare to start up
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* some VTs on tty1 and tty2 if somebody hits enter
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*/
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for ( ; ; ) {
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int wpid;
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int status;
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if ( pid1 == 0 && tty_commands[0] ) {
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if ( run_rc == TRUE ) {
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pid1 = run(tty_commands[0], rc_arguments, first_terminal, 0);
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} else {
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pid2 = run(tty_commands[1], arguments, first_terminal, 1);
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}
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}
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if ( pid2 == 0 && second_terminal && tty_commands[1] ) {
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pid2 = run(tty_commands[1], arguments, second_terminal, 1);
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}
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wpid = wait(&status);
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if ( wpid > 0 && wpid != pid1) {
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message(log, "pid %d exited, status=%x.\n", wpid, status);
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}
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if ( wpid == pid2 ) {
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pid2 = 0;
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}
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}
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}
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