Add ability to read /etc/passwd and /etc/group
Add the capability to read /etc/passwd and /etc/group for getpw* and
getgr* functions.
Bug: 27999086
Test: pwd, grp, grp_pwd_file unit tests
Test: Read in custom users/groups from /etc/{passwd,group}
Change-Id: Idc1f054af8a7ca34743a90493495f0ccc775a0d8
diff --git a/libc/bionic/grp_pwd_file.h b/libc/bionic/grp_pwd_file.h
new file mode 100644
index 0000000..ae8cd98
--- /dev/null
+++ b/libc/bionic/grp_pwd_file.h
@@ -0,0 +1,97 @@
+/*
+ * Copyright (C) 2018 The Android Open Source Project
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * * 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.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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
+ * COPYRIGHT OWNER 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.
+ */
+
+#ifndef GRP_PWD_FILE_H
+#define GRP_PWD_FILE_H
+
+#include <grp.h>
+#include <pwd.h>
+
+#include "private/bionic_lock.h"
+#include "private/bionic_macros.h"
+#include "private/grp_pwd.h"
+
+class MmapFile {
+ public:
+ MmapFile(const char* filename);
+ ~MmapFile();
+
+ template <typename Line>
+ bool FindById(uid_t uid, Line* line);
+ template <typename Line>
+ bool FindByName(const char* name, Line* line);
+
+ DISALLOW_COPY_AND_ASSIGN(MmapFile);
+
+ private:
+ enum class FileStatus {
+ Uninitialized,
+ Initialized,
+ Error,
+ };
+
+ bool GetFile(const char** start, const char** end);
+ bool DoMmap();
+
+ template <typename Line, typename Predicate>
+ bool Find(Line* line, Predicate predicate);
+
+ FileStatus status_ = FileStatus::Uninitialized;
+ Lock lock_;
+ const char* filename_ = nullptr;
+ const char* start_ = nullptr;
+ const char* end_ = nullptr;
+};
+
+class PasswdFile {
+ public:
+ PasswdFile(const char* filename);
+
+ bool FindById(uid_t id, passwd_state_t* passwd_state);
+ bool FindByName(const char* name, passwd_state_t* passwd_state);
+
+ DISALLOW_COPY_AND_ASSIGN(PasswdFile);
+
+ private:
+ MmapFile mmap_file_;
+};
+
+class GroupFile {
+ public:
+ GroupFile(const char* filename);
+
+ bool FindById(gid_t id, group_state_t* group_state);
+ bool FindByName(const char* name, group_state_t* group_state);
+
+ DISALLOW_COPY_AND_ASSIGN(GroupFile);
+
+ private:
+ MmapFile mmap_file_;
+};
+
+#endif