1 /* @(#)exec.c 4.1 (Berkeley) 12/21/80 */ 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 } 85