BSD 4_2 release

[unix-history] / usr / src / ucb / pascal / utilities / px_header.c

/*
* pxheader - program to sit in front of interpreter code to make shell mods
*            unnecessary to make Pascal obj's look like real programs.
*
* This program lives in /usr/lib/px_header
* Bill Joy UCB February 6, 1978
*/

static char sccsid[] = "@(#)px_header.c 1.5 4/8/83";

#include <stdio.h>
#include <sys/types.h>
#include <a.out.h>
#include "config.h"
#include "whoami.h"
#include "objfmt.h"

#define ETXTBSY 26
#define ADDR_LC \
       (START + HEADER_BYTES - sizeof (struct exec) - sizeof (struct pxhdr))
#define MAXARGS 512

extern  errno;

main(argc, argv)
       register int argc;
       register char *argv[];
{
       register int i;
       int codesiz, symtabsiz;
       register char *cp;
       char *largv[MAXARGS];
       int fd, pv[2], pid;

       cp = (char *)(ADDR_LC);
       codesiz = ((struct pxhdr *)(cp))->objsize + sizeof(struct pxhdr);
       symtabsiz = ((struct pxhdr *)(cp))->symtabsize;
       if (argc > MAXARGS - 3)
               error(2, "Too many arguments.\n");
       if (symtabsiz != 0) {
               largv[0] = "pxhdr";
               largv[1] = "/tmp/px00000";
               cp = &largv[1][11];
               for (i = getpid(); i > 0; i /= 10)
                       *cp-- = '0' + i % 10;
               fd = creat(largv[1], 0444);
               if (fd < 0)
                       error(3, "Cannot create /tmp file\n");
               for (i = 0; i < argc; i++)
                       largv[i + 2] = argv[i];
               largv[argc + 2] = 0;
               writeobj(fd, codesiz, symtabsiz);
               run(px_debug, largv);
               /* no return */
       }
       largv[0] = "pipe";
       for (i = 0; i < argc; i++)
               largv[i + 1] = argv[i];
       largv[argc + 1] = 0;
       pipe(pv);
       pid = fork();
       if (pid != 0) {
               if (pv[0] != 3) {
                       close(3);
                       dup(pv[0]);
                       close(pv[0]);
               }
               close(pv[1]);
               run(px_intrp, largv);
               /* no return */
       }
       writeobj(pv[1], codesiz, symtabsiz);
       exit(0);
}

writeobj(fd, codesiz, symtabsiz)
       int fd;
       int codesiz, symtabsiz;
{
       int i;
       register char *cp;

       cp = (char *)(ADDR_LC);
       while (codesiz != 0) {
               i = (codesiz < BUFSIZ) ? codesiz : BUFSIZ;
               write(fd, cp, i);
               cp += i;
               codesiz -= i;
       }
       while (symtabsiz != 0) {
               i = (symtabsiz < BUFSIZ) ? symtabsiz : BUFSIZ;
               write(fd, cp, i);
               cp += i;
               symtabsiz -= i;
       }
       close(fd);
}

run(prog, args)
       char *prog;
       char **args;
{
       for (;;) {
               execv(prog, args);
               if (errno != ETXTBSY)
                       break;
               sleep(2);
       }
       error(0, prog);
       error(1, " not found.\n");
}

error(errcode, cp)
       int errcode;
       register char *cp;
{
       register int i;
       register char *dp;

       dp = cp;
       i = 0;
       while (*dp++)
               i++;
       write(2, cp, i);
       if (errcode)
               exit(errcode);
}

exit(i)
{
       _exit(i);
}