101 lines
1.7 KiB
C
Executable File
101 lines
1.7 KiB
C
Executable File
#pragma ident "@(#)execvp.c 1.2 92/07/20 SMI" /* from S5R2 1.2 */
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/*LINTLIBRARY*/
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/*
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* execlp(name, arg,...,0) (like execl, but does path search)
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* execvp(name, argv) (like execv, but does path search)
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*/
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#include <sys/errno.h>
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#include <sys/param.h>
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#include <varargs.h>
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#define NULL 0
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static char *execat();
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static char *shell = "/bin/sh";
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extern char *getenv(), *strchr();
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extern unsigned sleep();
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extern int errno, execv();
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/*VARARGS1*/
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int
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execlp(name, va_alist)
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char *name;
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va_dcl
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{
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va_list args;
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va_start(args);
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return(execvp(name, (char **)args));
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}
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int
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execvp(name, argv)
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char *name, **argv;
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{
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char *pathstr;
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char fname[MAXPATHLEN];
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char *newargs[256];
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int i;
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register char *cp;
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register unsigned etxtbsy=1;
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register int eacces=0;
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if((pathstr = getenv("PATH")) == NULL)
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pathstr = ":/usr/ucb:/bin:/usr/bin";
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cp = strchr(name, '/')? "": pathstr;
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do {
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cp = execat(cp, name, fname);
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retry:
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(void) execv(fname, argv);
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switch(errno) {
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case ENOEXEC:
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newargs[0] = "sh";
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newargs[1] = fname;
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for(i=1; newargs[i+1]=argv[i]; ++i) {
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if(i >= 254) {
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errno = E2BIG;
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return(-1);
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}
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}
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(void) execv(shell, newargs);
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return(-1);
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case ETXTBSY:
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if(++etxtbsy > 5)
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return(-1);
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(void) sleep(etxtbsy);
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goto retry;
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case EACCES:
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++eacces;
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break;
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case ENOMEM:
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case E2BIG:
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case EFAULT:
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return(-1);
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}
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} while(cp);
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if(eacces)
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errno = EACCES;
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return(-1);
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}
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static char *
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execat(s1, s2, si)
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register char *s1, *s2;
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char *si;
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{
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register char *s;
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char *end;
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s = si;
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end = s + MAXPATHLEN;
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while(*s1 && *s1 != ':' && s < end)
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*s++ = *s1++;
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if(si != s && s < end)
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*s++ = '/';
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while(*s2 && s < end)
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*s++ = *s2++;
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*s = '\0';
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return(*s1? ++s1: 0);
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}
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