xref: /aosp_15_r20/system/core/fs_mgr/libfstab/include/fstab/fstab.h (revision 00c7fec1bb09f3284aad6a6f96d2f63dfc3650ad)
1 /*
2  * Copyright (C) 2012 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 #pragma once
18 
19 #include <stdint.h>
20 #include <sys/types.h>
21 
22 #include <functional>
23 #include <set>
24 #include <string>
25 #include <vector>
26 
27 std::string fs_mgr_get_slot_suffix();
28 std::string fs_mgr_get_other_slot_suffix();
29 
30 namespace android {
31 namespace fs_mgr {
32 
33 struct FstabEntry {
34     std::string blk_device;
35     std::vector<std::string> user_devices;
36     std::vector<int> device_aliased;
37     std::string logical_partition_name;
38     std::string mount_point;
39     std::string fs_type;
40     unsigned long flags = 0;
41     std::string fs_options;
42     std::string fs_checkpoint_opts;
43     std::string metadata_key_dir;
44     std::string metadata_encryption_options;
45     off64_t length = 0;
46     std::string label;
47     int partnum = -1;
48     int swap_prio = -1;
49     int max_comp_streams = 0;
50     off64_t zram_size = 0;
51     off64_t reserved_size = 0;
52     off64_t readahead_size_kb = -1;
53     std::string encryption_options;
54     off64_t erase_blk_size = 0;
55     off64_t logical_blk_size = 0;
56     std::string sysfs_path;
57     std::string vbmeta_partition;
58     uint64_t zram_backingdev_size = 0;
59     std::string avb_keys;
60     std::string lowerdir;
61     std::string avb_hashtree_digest;
62 
63     struct FsMgrFlags {
64         bool wait : 1;
65         bool check : 1;
66         bool crypt : 1;  // Now only used to identify adoptable storage volumes
67         bool nonremovable : 1;
68         bool vold_managed : 1;
69         bool recovery_only : 1;
70         bool no_emulated_sd : 1;  // No emulated sdcard daemon; sd card is the only external
71                                   // storage.
72         bool no_trim : 1;
73         bool file_encryption : 1;
74         bool formattable : 1;
75         bool slot_select : 1;
76         bool late_mount : 1;
77         bool no_fail : 1;
78         bool quota : 1;
79         bool avb : 1;
80         bool logical : 1;
81         bool checkpoint_blk : 1;
82         bool checkpoint_fs : 1;
83         bool first_stage_mount : 1;
84         bool slot_select_other : 1;
85         bool fs_verity : 1;
86         bool ext_meta_csum : 1;
87         bool fs_compress : 1;
88         bool overlayfs_remove_missing_lowerdir : 1;
89         bool is_zoned : 1;
90     } fs_mgr_flags = {};
91 
is_encryptableFstabEntry92     bool is_encryptable() const { return fs_mgr_flags.crypt; }
93 };
94 
95 // An Fstab is a collection of FstabEntry structs.
96 // The entries must be kept in the same order as they were seen in the fstab.
97 // Unless explicitly requested, a lookup on mount point should always return the 1st one.
98 using Fstab = std::vector<FstabEntry>;
99 
100 bool ReadFstabFromFile(const std::string& path, Fstab* fstab);
101 bool ReadFstabFromProcMounts(Fstab* fstab);
102 bool ReadFstabFromDt(Fstab* fstab, bool verbose = true);
103 bool ReadDefaultFstab(Fstab* fstab);
104 bool SkipMountingPartitions(Fstab* fstab, bool verbose = false);
105 
106 // The Fstab can contain multiple entries for the same mount point with different configurations.
107 std::vector<FstabEntry*> GetEntriesForMountPoint(Fstab* fstab, const std::string& path);
108 
109 // Like GetEntriesForMountPoint() but return only the first entry or nullptr if no entry is found.
110 FstabEntry* GetEntryForMountPoint(Fstab* fstab, const std::string& path);
111 const FstabEntry* GetEntryForMountPoint(const Fstab* fstab, const std::string& path);
112 
113 FstabEntry* GetEntryForMountPoint(Fstab* fstab, const std::string_view path,
114                                   const std::string_view fstype);
115 
116 // This method builds DSU fstab entries and transfer the fstab.
117 //
118 // fstab points to the unmodified fstab.
119 //
120 // dsu_partitions contains partition names, e.g.
121 //     dsu_partitions[0] = "system_gsi"
122 //     dsu_partitions[1] = "userdata_gsi"
123 //     dsu_partitions[2] = ...
124 void TransformFstabForDsu(Fstab* fstab, const std::string& dsu_slot,
125                           const std::vector<std::string>& dsu_partitions);
126 
127 std::set<std::string> GetBootDevices();
128 
129 // Get the Partition UUID the kernel loaded from if the bootloader passed it.
130 //
131 // If the kernel's Partition UUID is provided then we can use this to help
132 // identify which block device contains the filesystems we care about.
133 //
134 // NOTE: Nothing secures a UUID other than the convention that two disks
135 // aren't supposed to both have the same UUID. We still need other mechanisms
136 // to ensure we've got the right disk.
137 std::string GetBootPartUuid();
138 
139 // Return the name of the dm-verity device for the given fstab entry. This does
140 // not check whether the device is valid or exists; it merely returns the
141 // expected name.
142 std::string GetVerityDeviceName(const FstabEntry& entry);
143 
144 // Returns the Android Device Tree directory as specified in the kernel bootconfig or cmdline.
145 // If the platform does not configure a custom DT path, returns the standard one (based in procfs).
146 const std::string& GetAndroidDtDir();
147 
148 // Import the kernel bootconfig by calling the callback |fn| with each key-value pair.
149 void ImportBootconfig(const std::function<void(std::string, std::string)>& fn);
150 
151 // Get the kernel bootconfig value for |key|.
152 // Returns true if |key| is found in bootconfig.
153 // Otherwise returns false and |*out| is not modified.
154 bool GetBootconfig(const std::string& key, std::string* out);
155 
156 // Import the kernel cmdline by calling the callback |fn| with each key-value pair.
157 void ImportKernelCmdline(const std::function<void(std::string, std::string)>& fn);
158 
159 // Get the kernel cmdline value for |key|.
160 // Returns true if |key| is found in the kernel cmdline.
161 // Otherwise returns false and |*out| is not modified.
162 bool GetKernelCmdline(const std::string& key, std::string* out);
163 
164 // Return the "other" slot for the given slot suffix.
165 std::string OtherSlotSuffix(const std::string& suffix);
166 
167 bool GetBootconfigFromString(const std::string& bootconfig, const std::string& key,
168                              std::string* out);
169 
170 }  // namespace fs_mgr
171 }  // namespace android
172