2.9BSD - /usr/src/lib/c/gen/execvp.c

   1: /*	@(#)execvp.c	2.1	SCCS id keyword	*/
   2: /*
   3:  *	execlp(name, arg,...,0)	(like execl, but does path search)
   4:  *	execvp(name, argv)	(like execv, but does path search)
   5:  */
   6: #include <errno.h>
   7: #define NULL    0
   8: 
   9: static  char shell[] =  "/bin/sh";
  10: char    *execat(), *getenv();
  11: extern  errno;
  12: 
  13: execlp(name, argv)
  14: char *name, *argv;
  15: {
  16:     return(execvp(name, &argv));
  17: }
  18: 
  19: execvp(name, argv)
  20: char *name, **argv;
  21: {
  22:     char *pathstr;
  23:     register char *cp;
  24:     char fname[128];
  25:     char *newargs[256];
  26:     int i;
  27:     register unsigned etxtbsy = 1;
  28:     register eacces = 0;
  29: 
  30:     if ((pathstr = getenv("PATH")) == NULL)
  31:         pathstr = ":/bin:/usr/bin";
  32:     cp = index(name, '/')? "": pathstr;
  33: 
  34:     do {
  35:         cp = execat(cp, name, fname);
  36:     retry:
  37:         execv(fname, argv);
  38:         switch(errno) {
  39:         case ENOEXEC:
  40:             newargs[0] = "sh";
  41:             newargs[1] = fname;
  42:             for (i=1; newargs[i+1]=argv[i]; i++) {
  43:                 if (i>=254) {
  44:                     errno = E2BIG;
  45:                     return(-1);
  46:                 }
  47:             }
  48:             execv(shell, newargs);
  49:             return(-1);
  50:         case ETXTBSY:
  51:             if (++etxtbsy > 5)
  52:                 return(-1);
  53:             sleep(etxtbsy);
  54:             goto retry;
  55:         case EACCES:
  56:             eacces++;
  57:             break;
  58:         case ENOMEM:
  59:         case E2BIG:
  60:             return(-1);
  61:         }
  62:     } while (cp);
  63:     if (eacces)
  64:         errno = EACCES;
  65:     return(-1);
  66: }
  67: 
  68: static char *
  69: execat(s1, s2, si)
  70: register char *s1, *s2;
  71: char *si;
  72: {
  73:     register char *s;
  74: 
  75:     s = si;
  76:     while (*s1 && *s1 != ':' && *s1 != '-')
  77:         *s++ = *s1++;
  78:     if (si != s)
  79:         *s++ = '/';
  80:     while (*s2)
  81:         *s++ = *s2++;
  82:     *s = '\0';
  83:     return(*s1? ++s1: 0);
  84: }

Defined functions

Defined variables

Defined macros