From: Karel Zak <kzak@redhat.com>
Date: Wed, 18 May 2011 13:55:15 +0000 (+0200)
Subject: lib: [at.c] add readlink_at(), fix semantic for absolute paths
X-Git-Tag: v2.20-rc1~240
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=cdc9c4194aac3897feb2156ad2d3d5cb663b4365;p=thirdparty%2Futil-linux.git

lib: [at.c] add readlink_at(), fix semantic for absolute paths

Signed-off-by: Karel Zak <kzak@redhat.com>
---

diff --git a/include/at.h b/include/at.h
index 8e0a78db61..63a80f0c0c 100644
--- a/include/at.h
+++ b/include/at.h
@@ -25,4 +25,8 @@ extern int open_at(int dir, const char *dirname,
 extern FILE *fopen_at(int dir, const char *dirname, const char *filename,
 			int flags, const char *mode);
 
+extern ssize_t readlink_at(int dir, const char *dirname, const char *pathname,
+                    char *buf, size_t bufsiz);
+
+
 #endif /* UTIL_LINUX_AT_H */
diff --git a/lib/at.c b/lib/at.c
index e4838ec3cb..6d1cd13f73 100644
--- a/lib/at.c
+++ b/lib/at.c
@@ -11,6 +11,8 @@
 #include "at.h"
 #include "c.h"
 
+#undef HAVE_FSTATAT
+
 int fstat_at(int dir, const char *dirname, const char *filename,
 				struct stat *st, int nofollow)
 {
@@ -18,14 +20,18 @@ int fstat_at(int dir, const char *dirname, const char *filename,
 	return fstatat(dir, filename, st,
 			nofollow ? AT_SYMLINK_NOFOLLOW : 0);
 #else
-	char path[PATH_MAX];
-	int len;
+	if (*filename != '/') {
+		char path[PATH_MAX];
+		int len;
+
+		len = snprintf(path, sizeof(path), "%s/%s", dirname, filename);
+		if (len < 0 || len + 1 > sizeof(path))
+			return -1;
 
-	len = snprintf(path, sizeof(path), "%s/%s", dirname, filename);
-	if (len < 0 || len + 1 > sizeof(path))
-		return -1;
+		return nofollow ? lstat(path, st) : stat(path, st);
+	}
 
-	return nofollow ? lstat(path, st) : stat(path, st);
+	return nofollow ? lstat(filename, st) : stat(filename, st);
 #endif
 }
 
@@ -34,14 +40,17 @@ int open_at(int dir, const char *dirname, const char *filename, int flags)
 #ifdef HAVE_FSTATAT
 	return openat(dir, filename, flags);
 #else
-	char path[PATH_MAX];
-	int len;
+	if (*filename != '/') {
+		char path[PATH_MAX];
+		int len;
 
-	len = snprintf(path, sizeof(path), "%s/%s", dirname, filename);
-	if (len < 0 || len + 1 > sizeof(path))
-		return -1;
+		len = snprintf(path, sizeof(path), "%s/%s", dirname, filename);
+		if (len < 0 || len + 1 > sizeof(path))
+			return -1;
 
-	return open(path, flags);
+		return open(path, flags);
+	}
+	return open(filename, flags);
 #endif
 }
 
@@ -56,6 +65,26 @@ FILE *fopen_at(int dir, const char *dirname, const char *filename, int flags,
 	return fdopen(fd, mode);
 }
 
+ssize_t readlink_at(int dir, const char *dirname, const char *pathname,
+		    char *buf, size_t bufsiz)
+{
+#ifdef HAVE_FSTATAT
+	return readlinkat(dir, pathname, buf, bufsiz);
+#else
+	if (*pathname != '/') {
+		char path[PATH_MAX];
+		int len;
+
+		len = snprintf(path, sizeof(path), "%s/%s", dirname, pathname);
+		if (len < 0 || len + 1 > sizeof(path))
+			return -1;
+
+		return readlink(path, buf, bufsiz);
+	}
+	return readlink(pathname, buf, bufsiz);
+#endif
+}
+
 #ifdef TEST_PROGRAM__DISABLED_FOR_NOW
 #include <errno.h>
 #include <sys/types.h>