add LCC - a better C-Compiler for WEGA

WEGA/contrib/lcc/lib/libc/port/gen/execvp.c

@@ -0,0 +1,87 @@
+/*
+ *	execlp(name, arg,...,0)	(like execl, but does path search)
+ *	execvp(name, argv)	(like execv, but does path search)
+ */
+#include <errno.h>
+#define	NULL	0
+
+static char *execat(), shell[] = "/bin/sh";
+extern char *getenv(), *strchr();
+extern unsigned sleep();
+extern int errno, execv();
+
+/*VARARGS1*/
+int
+execlp(name, argv)
+char	*name, *argv;
+{
+	return(execvp(name, &argv));
+}
+
+int
+execvp(name, argv)
+char	*name, **argv;
+{
+	char	*pathstr;
+	char	fname[128];
+	char	*newargs[256];
+	int	i;
+	register char	*cp;
+	register unsigned etxtbsy=1;
+	register int eacces=0;
+
+	if((pathstr = getenv("PATH")) == NULL)
+		pathstr = ":/bin:/usr/bin";
+	cp = strchr(name, '/')? "": pathstr;
+
+	do {
+		cp = execat(cp, name, fname);
+	retry:
+		(void) execv(fname, argv);
+		switch(errno) {
+		case ENOEXEC:
+			newargs[0] = "sh";
+			newargs[1] = fname;
+			for(i=1; newargs[i+1]=argv[i]; ++i) {
+				if(i >= 254) {
+					errno = E2BIG;
+					return(-1);
+				}
+			}
+			(void) execv(shell, newargs);
+			return(-1);
+		case ETXTBSY:
+			if(++etxtbsy > 5)
+				return(-1);
+			(void) sleep(etxtbsy);
+			goto retry;
+		case EACCES:
+			++eacces;
+			break;
+		case ENOMEM:
+		case E2BIG:
+			return(-1);
+		}
+	} while(cp);
+	if(eacces)
+		errno = EACCES;
+	return(-1);
+}
+
+static char *
+execat(s1, s2, si)
+register char *s1, *s2;
+char	*si;
+{
+	register char	*s;
+
+	s = si;
+	while(*s1 && *s1 != ':')
+		*s++ = *s1++;
+	if(si != s)
+		*s++ = '/';
+	while(*s2)
+		*s++ = *s2++;
+	*s = '\0';
+	return(*s1? ++s1: 0);
+}