1 files changed, 146 insertions, 0 deletions
diff --git a/shell_cmds/which/which.c b/shell_cmds/which/which.c
new file mode 100644
index 0000000..7e9d662
--- /dev/null
+++ b/shell_cmds/which/which.c
@@ -0,0 +1,146 @@
+/**
+ * Copyright (c) 2000 Dan Papasian.  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. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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/cdefs.h>
+
+__FBSDID("$FreeBSD: head/usr.bin/which/which.c 227245 2011-11-06 18:50:26Z ed $");
+
+#include <sys/stat.h>
+#include <sys/param.h>
+
+#include <err.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+static void	 usage(void);
+static int	 print_matches(char *, char *);
+	
+static int 	 silent;
+static int 	 allpaths;
+
+int
+main(int argc, char **argv)
+{
+	char *p, *path;
+	ssize_t pathlen;
+	int opt, status;
+
+	status = EXIT_SUCCESS;
+
+	while ((opt = getopt(argc, argv, "as")) != -1) {
+		switch (opt) {
+		case 'a':
+			allpaths = 1;
+			break;
+		case 's':
+			silent = 1;
+			break;
+		default:
+			usage();
+			break;
+		}
+	}
+
+	argv += optind;
+	argc -= optind;
+
+	if (argc == 0)
+		usage();
+
+	if ((p = getenv("PATH")) == NULL)
+		exit(EXIT_FAILURE);
+	pathlen = strlen(p) + 1;
+	path = malloc(pathlen);
+	if (path == NULL)
+		err(EXIT_FAILURE, NULL);
+
+	while (argc > 0) {
+		memcpy(path, p, pathlen);
+	
+		if (strlen(*argv) >= FILENAME_MAX ||
+		    print_matches(path, *argv) == -1)
+			status = EXIT_FAILURE;
+
+		argv++;
+		argc--;
+	}
+
+	exit(status);
+}
+
+static void
+usage(void)
+{
+
+	(void)fprintf(stderr, "usage: which [-as] program ...\n");
+	exit(EXIT_FAILURE);
+}
+
+static int
+is_there(char *candidate)
+{
+	struct stat fin;
+
+	/* XXX work around access(2) false positives for superuser */
+	if (access(candidate, X_OK) == 0 &&
+	    stat(candidate, &fin) == 0 &&
+	    S_ISREG(fin.st_mode) &&
+	    (getuid() != 0 ||
+	    (fin.st_mode & (S_IXUSR | S_IXGRP | S_IXOTH)) != 0)) {
+		if (!silent)
+			printf("%s\n", candidate);
+		return (1);
+	}
+	return (0);
+}
+
+static int
+print_matches(char *path, char *filename)
+{
+	char candidate[PATH_MAX];
+	const char *d;
+	int found;
+
+	if (strchr(filename, '/') != NULL)
+		return (is_there(filename) ? 0 : -1);
+	found = 0;
+	while ((d = strsep(&path, ":")) != NULL) {
+		if (*d == '\0')
+			d = ".";
+		if (snprintf(candidate, sizeof(candidate), "%s/%s", d,
+		    filename) >= (int)sizeof(candidate))
+			continue;
+		if (is_there(candidate)) {
+			found = 1;
+			if (!allpaths)
+				break;
+		}
+	}
+	return (found ? 0 : -1);
+}
+