From 2e838897cc574a9147bcf0b1681aeeaa44001fce Mon Sep 17 00:00:00 2001
From: Nathan Wagner <nw@hydaspes.if.org>
Date: Sun, 26 Apr 2015 00:13:36 +0000
Subject: [PATCH] implemented pwd

---
 utils/pwd/pwd.c | 94 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 94 insertions(+)
 create mode 100644 utils/pwd/pwd.c

diff --git a/utils/pwd/pwd.c b/utils/pwd/pwd.c
new file mode 100644
index 0000000..41e2ff4
--- /dev/null
+++ b/utils/pwd/pwd.c
@@ -0,0 +1,94 @@
+#include <stdlib.h>
+#include <stdio.h>
+#include <errno.h>
+#include <unistd.h>
+#include <limits.h>
+#include <string.h>
+
+static int has_dot_or_dotdot(char *path) {
+	if (!path) return 0;
+
+	while (*path) {
+		if (*path == '/') {
+			path++;
+			continue;
+		}
+		if (*path == '.') {
+			path++;
+			if (*path == '.') path++;
+			switch (path[0]) {
+				case '/':
+				case 0:
+					return 1;
+				default:
+					break;
+			}
+		}
+		while (*path && *path != '/') {
+			path++;
+		}
+	}
+	return 0;
+}
+
+static void fillcwd(char *s, size_t n) {
+	if (!getcwd(s, n)) {
+		switch (errno) {
+			case ERANGE:
+				fprintf(stderr, "pwd: path too long\n");
+				exit(1);
+			default:
+				perror("pwd");
+				exit(1);
+		}
+	}
+}
+
+int main(int ac, char *av[]) {
+	int cleansym = 0;
+	char cwd[PATH_MAX];
+	char *pwd;
+	char *envpwd;
+	int arg;
+
+	for (arg=1; arg < ac; arg++) {
+		if (av[arg][0] == '-') {
+		       if (av[arg][1] == 'P' && av[arg][2] == 0) {
+			       cleansym = 1;
+		       } else if (av[arg][1] == 'L' && av[arg][2] == 0) {
+			       cleansym = 0;
+		       }
+		} else {
+			fprintf(stderr, "usage: pwd [-L|-P]\n");
+			exit(1);
+		}
+	}
+
+	if (!getcwd(cwd, sizeof cwd)) {
+		switch (errno) {
+			case ERANGE:
+				fprintf(stderr, "pwd: path too long\n");
+				exit(1);
+			default:
+				perror("pwd");
+				exit(1);
+		}
+	}
+	pwd = cwd;
+
+	if (!cleansym) {
+		envpwd = getenv("PWD");
+		if (envpwd && !has_dot_or_dotdot(envpwd)) {
+			if (chdir(envpwd) != -1) {
+				fillcwd(cwd, sizeof cwd);
+				if (strcmp(cwd, envpwd)) {
+					pwd = envpwd;
+				}
+			}
+		}
+	}
+
+	printf("%s\n", pwd);
+	return 0;
+}
+
-- 
2.40.0