Initial Spring 2016 commit.

userland/lib/libc/stdlib/system.c

@@ -0,0 +1,91 @@
+/*
+ * Copyright (c) 2000, 2001, 2002, 2003, 2004, 2005, 2008, 2009
+ *	The President and Fellows of Harvard College.
+ *
+ * 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 UNIVERSITY 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 UNIVERSITY 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 <errno.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+
+/*
+ * system(): ANSI C
+ *
+ * Run a command.
+ */
+
+#define MAXCMDSIZE 2048
+#define MAXARGS    128
+
+int
+system(const char *cmd)
+{
+	/*
+	 * Ordinarily, you call the shell to process the command.
+	 * But we don't know that the shell can do that. So, do it
+	 * ourselves.
+	 */
+
+	char tmp[MAXCMDSIZE];
+	char *argv[MAXARGS+1];
+	int nargs=0;
+	char *s;
+	int pid, status;
+
+	if (strlen(cmd) >= sizeof(tmp)) {
+		errno = E2BIG;
+		return -1;
+	}
+	strcpy(tmp, cmd);
+
+	for (s = strtok(tmp, " \t"); s; s = strtok(NULL, " \t")) {
+		if (nargs < MAXARGS) {
+			argv[nargs++] = s;
+		}
+		else {
+			errno = E2BIG;
+			return 1;
+		}
+	}
+
+	argv[nargs] = NULL;
+
+	pid = fork();
+	switch (pid) {
+	    case -1:
+		return -1;
+	    case 0:
+		/* child */
+		execv(argv[0], argv);
+		/* exec only returns if it fails */
+		_exit(255);
+	    default:
+		/* parent */
+		waitpid(pid, &status, 0);
+		return status;
+	}
+}