00001 /*
00002     Display session- and process-group-related information
00003     AUP2, Sec. 4.03.5
00004 
00005     Copyright 2003 by Marc J. Rochkind. All rights reserved.
00006     May be copied only for purposes and under conditions described
00007     on the Web page www.basepath.com/aup/copyright.htm.
00008 
00009     The Example Files are provided "as is," without any warranty;
00010     without even the implied warranty of merchantability or fitness
00011     for a particular purpose. The author and his publisher are not
00012     responsible for any damages, direct or incidental, resulting
00013     from the use or non-use of these Example Files.
00014 
00015     The Example Files may contain defects, and some contain deliberate
00016     coding mistakes that were included for educational reasons.
00017     You are responsible for determining if and how the Example Files
00018     are to be used.
00019 
00020 */
00021 #include "defs.h"
00022 
00023 /*[showpginfo]*/
00024 #include <termios.h>
00025 
00026 static void showpginfo(const char *msg)
00027 {
00028     int fd;
00029 
00030     printf("%s\n", msg);
00031     printf("\tprocess ID = %ld; parent = %ld\n",
00032       (long)getpid(), (long)getppid());
00033     printf("\tsession ID = %ld; process-group ID = %ld\n",
00034       (long)getsid(0), (long)getpgid(0));
00035     ec_neg1( fd = open("/dev/tty", O_RDWR) )
00036     printf("\tcontrolling terminal's foreground process-group ID = %ld\n",
00037       (long)tcgetpgrp(fd));
00038 #if _XOPEN_VERSION >= 4
00039     printf("\tcontrolling-terminal's session ID = %ld\n",
00040       (long)tcgetsid(fd));
00041 #else
00042     printf("\tcontrolling-terminal's session ID = %ld\n",
00043       (long)getsid(tcgetpgrp(fd)));
00044 #endif
00045     ec_neg1( close(fd) )
00046     return;
00047 
00048 EC_CLEANUP_BGN
00049     EC_FLUSH("showpginfo")
00050 EC_CLEANUP_END
00051 }
00052 /*[catchsig]*/
00053 static void catchsig(int signo)
00054 {
00055     if (signo == SIGCONT)
00056         showpginfo("got SIGCONT");
00057 }
00058 /*[main]*/
00059 int main(void)
00060 {
00061     struct sigaction act;
00062 
00063     memset(&act, 0, sizeof(act));
00064     act.sa_handler = catchsig;
00065     ec_neg1( sigaction(SIGCONT, &act, NULL) )
00066     showpginfo("initial call");
00067     while (true)
00068         sleep(10000);
00069 EC_CLEANUP_BGN
00070     exit(EXIT_FAILURE);
00071 EC_CLEANUP_END
00072 }
00073 /*[]*/
c4/pginfo.c
