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/* alias.c */
/* Author:
* Peter Reinig
* Universitaet Kaiserslautern
* Postfach 3049
* 7650 Kaiserslautern
* W. Germany
* reinig@physik.uni-kl.de
*
* adapted for IBM's OS/2 compiler by herbert
* tweaked for DOS/Win32/OS2 portability by Steve Kirkendall
*/
/* This tiny program executes elvis with the flags that are appropriate
* for a given command name. This program is used only on systems that
* don't allow UNIX-style file links.
*
* The benefit of this program is: instead of having 5 copies of elvis
* on your disk, you only need one copy of elvis and 4 copies of this
* little program.
*/
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <process.h>
#include <io.h>
#include "osdef.h"
/* This is the name of the real elvis program, with the directory name or
* the ".exe" extension.
*/
#define ELVIS "elvis"
/* These are alternative names. You can use these with -DARGV0=... */
#define VI "vi"
#define EX "ex"
#define VIEW "view"
#define INPUT "input"
/* if the shell doesn't set argv[0] to the program name, then argv[0] will
* be set to this value. Usually this value is set by compiling elvis with
* -DARGV0=EX or something like that, so this is just the default.
*/
#ifndef ARGV0
# define ARGV0 VI
#endif
/* Win32 seems to have developed an inability to exec() correctly. The shell
* thinks the program has exited when in fact it has merely exec'ed some
* other function. This messes up the ex/vi/view aliases for elvis. To work
* around it, we SPAWN elvis and wait for it to return before the alias exits.
* This wastes a little memory, but at least it works.
*/
#if _MSC_VER >= 900 /* 32-bit compiler for Windows */
# define execvp(p,a) (i = _spawnvp(_P_WAIT, p,a)); if (i >= 0) exit(i);
#endif
main(argc, argv)
int argc;
char *argv[];
{
int i, j;
int letter;
char **argblk;
char fullelvis[256];
char *scan;
/* if argv[0] isn't set, then set it now */
if (!argv[0])
argv[0] = ARGV0;
/* allocate enough space for a copy of the argument list, plus a
* terminating NULL, plus maybe an added flag.
*/
argblk = (char **) malloc((argc + 2) * sizeof(char *));
if (!argblk)
{
perror(argv[0]);
exit(2);
}
/* find the last letter in the invocation name of this program */
/* we almost certainly must bypass ".EXE" or ".TTP" from argv[0] */
i = strlen(argv[0]);
if (i > 4 && argv[0][i - 4] == '.')
i -= 4;
letter = argv[0][i - 1];
/* find the name of elvis. First try looking for ELVIS.EXE in the
* same directory as the VI.EXE file. If that doesn't work, then
* just call it ELVIS and hope that it can be found somewhere in the
* execution path.
*/
strcpy(fullelvis, argv[0]);
scan = strrchr(fullelvis, '\\');
if (scan)
{
for (scan++, j = 0; ELVIS[j]; )
*scan++ = ELVIS[j++];
while (i >= 0 && argv[0][i])
*scan++ = argv[0][i++];
*scan = '\0';
if (access(fullelvis, 0) != 0)
strcpy(fullelvis, ELVIS);
}
else /* no path information in argv[0], try to load via PATH */
strcpy(fullelvis, ELVIS);
/* copy argv to argblk, possibly inserting a flag such as "-R" */
argblk[0] = fullelvis;
i = j = 1;
switch (letter)
{
case 'w': /* "view" */
case 'W':
argblk[i++] = "-R";
break;
case 'x': /* "ex" */
case 'X':
argblk[i++] = "-e";
break;
case 't': /* "input" */
case 'T':
argblk[i++] = "-i";
break;
}
while (j < argc)
{
argblk[i++] = argv[j++];
}
argblk[i] = (char *)0;
/* execute the real ELVIS program */
(void)execvp(argblk[0], argblk);
perror(ELVIS);
}
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