Initial Contribution
diff --git a/libc/unistd/exec.c b/libc/unistd/exec.c
new file mode 100644
index 0000000..cbb98b3
--- /dev/null
+++ b/libc/unistd/exec.c
@@ -0,0 +1,244 @@
+/* $OpenBSD: exec.c,v 1.18 2005/08/08 08:05:34 espie Exp $ */
+/*-
+ * Copyright (c) 1991, 1993
+ * The Regents of the University of California. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ * may be used to endorse or promote products derived from this software
+ * without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <sys/param.h>
+#include <sys/types.h>
+#include <sys/uio.h>
+#include <errno.h>
+#include <unistd.h>
+#include <limits.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+#include <paths.h>
+#include <stdarg.h>
+#include <alloca.h>
+
+extern char **environ;
+
+int
+execl(const char *name, const char *arg, ...)
+{
+ va_list ap;
+ char **argv;
+ int n;
+
+ va_start(ap, arg);
+ n = 1;
+ while (va_arg(ap, char *) != NULL)
+ n++;
+ va_end(ap);
+ argv = alloca((n + 1) * sizeof(*argv));
+ if (argv == NULL) {
+ errno = ENOMEM;
+ return (-1);
+ }
+ va_start(ap, arg);
+ n = 1;
+ argv[0] = (char *)arg;
+ while ((argv[n] = va_arg(ap, char *)) != NULL)
+ n++;
+ va_end(ap);
+ return (execve(name, argv, environ));
+}
+
+int
+execle(const char *name, const char *arg, ...)
+{
+ va_list ap;
+ char **argv, **envp;
+ int n;
+
+ va_start(ap, arg);
+ n = 1;
+ while (va_arg(ap, char *) != NULL)
+ n++;
+ va_end(ap);
+ argv = alloca((n + 1) * sizeof(*argv));
+ if (argv == NULL) {
+ errno = ENOMEM;
+ return (-1);
+ }
+ va_start(ap, arg);
+ n = 1;
+ argv[0] = (char *)arg;
+ while ((argv[n] = va_arg(ap, char *)) != NULL)
+ n++;
+ envp = va_arg(ap, char **);
+ va_end(ap);
+ return (execve(name, argv, envp));
+}
+
+int
+execlp(const char *name, const char *arg, ...)
+{
+ va_list ap;
+ char **argv;
+ int n;
+
+ va_start(ap, arg);
+ n = 1;
+ while (va_arg(ap, char *) != NULL)
+ n++;
+ va_end(ap);
+ argv = alloca((n + 1) * sizeof(*argv));
+ if (argv == NULL) {
+ errno = ENOMEM;
+ return (-1);
+ }
+ va_start(ap, arg);
+ n = 1;
+ argv[0] = (char *)arg;
+ while ((argv[n] = va_arg(ap, char *)) != NULL)
+ n++;
+ va_end(ap);
+ return (execvp(name, argv));
+}
+
+int
+execv(const char *name, char * const *argv)
+{
+ (void)execve(name, argv, environ);
+ return (-1);
+}
+
+int
+execvp(const char *name, char * const *argv)
+{
+ char **memp;
+ int cnt, lp, ln, len;
+ char *p;
+ int eacces = 0;
+ char *bp, *cur, *path, buf[MAXPATHLEN];
+
+ /*
+ * Do not allow null name
+ */
+ if (name == NULL || *name == '\0') {
+ errno = ENOENT;
+ return (-1);
+ }
+
+ /* If it's an absolute or relative path name, it's easy. */
+ if (strchr(name, '/')) {
+ bp = (char *)name;
+ cur = path = NULL;
+ goto retry;
+ }
+ bp = buf;
+
+ /* Get the path we're searching. */
+ if (!(path = getenv("PATH")))
+ path = _PATH_DEFPATH;
+ len = strlen(path) + 1;
+ cur = alloca(len);
+ if (cur == NULL) {
+ errno = ENOMEM;
+ return (-1);
+ }
+ strlcpy(cur, path, len);
+ path = cur;
+ while ((p = strsep(&cur, ":"))) {
+ /*
+ * It's a SHELL path -- double, leading and trailing colons
+ * mean the current directory.
+ */
+ if (!*p) {
+ p = ".";
+ lp = 1;
+ } else
+ lp = strlen(p);
+ ln = strlen(name);
+
+ /*
+ * If the path is too long complain. This is a possible
+ * security issue; given a way to make the path too long
+ * the user may execute the wrong program.
+ */
+ if (lp + ln + 2 > (int)sizeof(buf)) {
+ struct iovec iov[3];
+
+ iov[0].iov_base = "execvp: ";
+ iov[0].iov_len = 8;
+ iov[1].iov_base = p;
+ iov[1].iov_len = lp;
+ iov[2].iov_base = ": path too long\n";
+ iov[2].iov_len = 16;
+ (void)writev(STDERR_FILENO, iov, 3);
+ continue;
+ }
+ bcopy(p, buf, lp);
+ buf[lp] = '/';
+ bcopy(name, buf + lp + 1, ln);
+ buf[lp + ln + 1] = '\0';
+
+retry: (void)execve(bp, argv, environ);
+ switch(errno) {
+ case E2BIG:
+ goto done;
+ case EISDIR:
+ case ELOOP:
+ case ENAMETOOLONG:
+ case ENOENT:
+ break;
+ case ENOEXEC:
+ for (cnt = 0; argv[cnt]; ++cnt)
+ ;
+ memp = alloca((cnt + 2) * sizeof(char *));
+ if (memp == NULL)
+ goto done;
+ memp[0] = "sh";
+ memp[1] = bp;
+ bcopy(argv + 1, memp + 2, cnt * sizeof(char *));
+ (void)execve(_PATH_BSHELL, memp, environ);
+ goto done;
+ case ENOMEM:
+ goto done;
+ case ENOTDIR:
+ break;
+ case ETXTBSY:
+ /*
+ * We used to retry here, but sh(1) doesn't.
+ */
+ goto done;
+ case EACCES:
+ eacces = 1;
+ break;
+ default:
+ goto done;
+ }
+ }
+ if (eacces)
+ errno = EACCES;
+ else if (!errno)
+ errno = ENOENT;
+done:
+ return (-1);
+}