From 02d288d89683e99fd18fe9f54d4e731a6c474a4f Mon Sep 17 00:00:00 2001
From: Rich Felker <dalias@aerifal.cx>
Date: Thu, 12 Apr 2012 01:38:35 -0400
Subject: initial check-in

---
 src/pwd.c | 90 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 90 insertions(+)
 create mode 100644 src/pwd.c

(limited to 'src/pwd.c')

diff --git a/src/pwd.c b/src/pwd.c
new file mode 100644
index 0000000..8ccd28b
--- /dev/null
+++ b/src/pwd.c
@@ -0,0 +1,90 @@
+/*
+ * pwd.c
+ * Implementation of SUSv3 XCU pwd utility
+ * Copyright © 2007 Rich Felker
+ * Licensed under the terms of the GNU General Public License, v2 or later
+ */
+
+/* NOTE: This implementation assumes PATH_MAX is defined and correct. */
+
+#include <limits.h>
+#include <unistd.h>
+#include <sys/stat.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+
+static int my_write(int fd, const char *s, size_t l)
+{
+	if (!l) l = strlen(s);
+	while (l) {
+		ssize_t n = write(fd, s, l);
+		if (n<0) return -1;
+		s += n; l -= n;
+	}
+	return 0;
+}
+
+static void my_perror(char *prog, char *msg)
+{
+	char *err = strerror(errno);
+	write(2, prog, strlen(prog));
+	write(2, ": ", 2);
+	write(2, msg, strlen(msg));
+	write(2, ": ", 2);
+	write(2, err, strlen(err));
+	write(2, "\n", 1);
+}
+
+static int is_rel(const char *s)
+{
+	unsigned dots=0, slash=1;
+	if (*s++ != '/') return 1;
+	for (; *s; s++) {
+		if (*s == '/') {
+			if (dots-1<2) return 1;
+			dots=0;
+		}
+		else slash=1;
+		if (slash && *s == '.') dots++;
+		else dots=slash=0;
+	}
+	return dots-1<2;
+}
+
+int main(int argc, char *argv[])
+{
+	int i, j;
+	int p=0;
+	char buf[PATH_MAX+2];
+	struct stat st1, st2;
+	char *pwd;
+	
+	for (i=1; i<argc && argv[i][0]=='-'; i++)
+		for (j=1; argv[i][j]; j++) {
+			switch (argv[i][j]) {
+			case 'L': p=0; continue;
+			case 'P': p=1;
+			case 0: continue;
+			}
+invalid:
+			errno = EINVAL;
+			my_perror(argv[0], argv[i]);
+			return 1;
+		}
+	if (i<argc) goto invalid;
+	if (p || !(pwd=getenv("PWD")) || is_rel(pwd)
+	 || stat(pwd, &st1) || stat(".", &st2)
+	 || st1.st_dev != st2.st_dev
+	 || st1.st_ino != st2.st_ino) {
+		if (!getcwd(buf, sizeof buf)) {
+			my_perror(argv[0], "getcwd");
+			return 1;
+		}
+	} else {
+		/* safe because stat succeeded */
+		strcpy(buf, pwd);
+	}
+	strcat(buf, "\n");
+	return my_write(1, buf, 0) != 0;
+}
-- 
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