gtags-cscope/exec.c

gtags-cscope/exec.c
/* */
This source file includes following definitions.
execute
myexecvp
myfork
join
   1 /*===========================================================================
   2  Copyright (c) 1998-2000, The Santa Cruz Operation 
   3  All rights reserved.
   4  
   5  Redistribution and use in source and binary forms, with or without
   6  modification, are permitted provided that the following conditions are met:
   7 
   8  *Redistributions of source code must retain the above copyright notice,
   9  this list of conditions and the following disclaimer.
  10 
  11  *Redistributions in binary form must reproduce the above copyright notice,
  12  this list of conditions and the following disclaimer in the documentation
  13  and/or other materials provided with the distribution.
  14 
  15  *Neither name of The Santa Cruz Operation nor the names of its contributors
  16  may be used to endorse or promote products derived from this software
  17  without specific prior written permission. 
  18 
  19  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ``AS
  20  IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
  21  THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  22  PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE
  23  LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  24  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  25  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  26  INTERRUPTION)
  27  HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  28  LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  29  OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
  30  DAMAGE. 
  31  =========================================================================*/
  32 
  33 /** @file
  34  *      process execution functions
  35  *
  36  *      cscope - interactive C symbol cross-reference
  37  */
  38 
  39 #include <unistd.h>
  40 #include "global-cscope.h"
  41 #include <stdarg.h>
  42 #include <sys/types.h>      /* pid_t */
  43 #ifdef __DJGPP__
  44 #include <process.h>
  45 #endif
  46 #if defined(USE_NCURSES) && !defined(RENAMED_NCURSES)
  47 #include <ncurses.h>
  48 #else
  49 #include <curses.h>
  50 #endif
  51 
  52 #if defined(__MSDOS__) || (defined(_WIN32) && !defined(__CYGWIN__))
  53 #define HAVE_FORK 0
  54 #else
  55 #include <sys/wait.h>
  56 #define HAVE_FORK 1
  57 #endif
  58 
  59 static char const rcsid[] = "$Id: exec.c,v 1.3 2012/10/13 07:02:04 shigio Exp $";
  60 
  61 static  sighandler_t oldsigquit; /**< old value of quit signal */
  62 static  sighandler_t oldsighup; /**< old value of hangup signal */
  63 static  sighandler_t oldsigtstp; /**< old value of @VAR{SIGTSTP} */
  64 
  65 #if HAVE_FORK /* none of these is needed, there */
  66 static  int     join(pid_t p);
  67 static  int     myexecvp(char *a, char **args);
  68 static  pid_t   myfork(void);
  69 #endif
  70 
  71 /** execute forks and executes a program or shell script, waits for it to
  72  * finish, and returns its exit code.
  73  */
  74 
  75 /*VARARGS1*/
  76 int
  77 execute(char *a, ...)   /* note: "exec" is already defined on u370 */
  78 {
  79         va_list ap;
  80         int     exitcode = -1;  /* initialize, to avoid warning */
  81         char    *argv[BUFSIZ];
  82         pid_t   p;
  83 
  84         /* fork and exec the program or shell script */
  85         endwin();       /* restore the terminal modes */
  86         mousecleanup();
  87         fflush(stdout);
  88         va_start(ap, a);
  89         for (p = 0; (argv[p] = va_arg(ap, char *)) != 0; p++)
  90                 ;
  91 #if !HAVE_FORK
  92         /* HBB 20010313: in MSDOG, everything is completely different.
  93          * No fork()/exec()/wait(), but rather a single libc call: */
  94         exitcode = spawnvp(P_WAIT, a, argv);
  95 #else
  96         if ((p = myfork()) == 0) {
  97                 myexecvp(a, argv);      /* child */
  98         }
  99         else {
 100                 exitcode = join(p);     /* parent */
 101         }
 102 #endif /* MSDOS */
 103         
 104         /* the menu and scrollbar may be changed by the command executed */
 105 #if UNIXPC || !TERMINFO
 106 # ifndef __DJGPP__ /* leave CRLF handling as is */      
 107         nonl();
 108 # endif
 109         raw();  /* endwin() turns off cbreak mode so restore it */
 110         noecho();
 111 #endif
 112         mousemenu();
 113         drawscrollbar(topline, nextline);
 114         va_end(ap);
 115         return(exitcode);
 116 }
 117 
 118 #if HAVE_FORK /* None of the following functions is used there */
 119 
 120 /** myexecvp is an interface to the @NAME{execvp} system call to
 121  * modify @CODE{argv[0]} to reference the last component of its path-name.
 122  */
 123 static int
 124 myexecvp(char *a, char **args)
 125 {
 126     char    msg[MSGLEN + 1];
 127         
 128     /* modify argv[0] to reference the last component of its path name */
 129     args[0] = mybasename(args[0]);
 130 
 131     /* execute the program or shell script */
 132     execvp(a, args);    /* returns only on failure */
 133     snprintf(msg, sizeof(msg), "\nCannot exec %s", a);
 134     perror(msg);                /* display the reason */
 135     askforreturn();             /* wait until the user sees the message */
 136     myexit(1);          /* exit the child */
 137     /* NOTREACHED */
 138 }
 139 
 140 /** myfork acts like fork but also handles signals */
 141 
 142 static pid_t
 143 myfork(void)
 144 {
 145         pid_t   p;              /* process number */
 146 
 147         p = fork();
 148         
 149         /* the parent ignores the interrupt, quit, and hangup signals */
 150         if (p > 0) {
 151                 oldsigquit = signal(SIGQUIT, SIG_IGN);
 152                 oldsighup = signal(SIGHUP, SIG_IGN);
 153 #ifdef SIGTSTP          
 154                 oldsigtstp = signal(SIGTSTP, SIG_DFL);
 155 #endif          
 156         }
 157         /* so they can be used to stop the child */
 158         else if (p == 0) {
 159                 signal(SIGINT, SIG_DFL);
 160                 signal(SIGQUIT, SIG_DFL);
 161                 signal(SIGHUP, SIG_DFL);
 162 #ifdef SIGTSTP
 163                 signal(SIGTSTP, SIG_DFL);
 164 #endif                  
 165         }
 166         /* check for fork failure */
 167         if (p == -1) {
 168                 myperror("Cannot fork");
 169         }
 170         return p;
 171 }
 172 
 173 /** join is the compliment of fork */
 174 
 175 static int
 176 join(pid_t p) 
 177 {
 178         int     status;  
 179         pid_t   w;
 180 
 181         /* wait for the correct child to exit */
 182         do {
 183                 w = wait(&status);
 184         } while (p != -1 && w != p);
 185 
 186         /* restore signal handling */
 187         signal(SIGQUIT, oldsigquit);
 188         signal(SIGHUP, oldsighup);
 189 #ifdef SIGTSTP
 190         signal(SIGTSTP, oldsigtstp);
 191 #endif  
 192 
 193         /* return the child's exit code */
 194         return(status >> 8);
 195 }
 196 
 197 #endif /* !MSDOS */
/* */
root/gtags-cscope/exec.c

DEFINITIONS
