libdm: Add dm-crypt and dm-default-key support to libdm.

Also, add an Emplace() method to DmTable to make target construction
easier. For example,

    table.AddTarget(std::make_unique<DmTargetLinear>(...));

Becomes:

    table.Emplace<DmTargetLinear>(...);

Bug: 132206403
Test: libdm_test gtest
Change-Id: Iac62c74546ebaa660cb32d6894a019bdac24a305

fs_mgr/libdm/dm_target.cpp

@@ -16,6 +16,9 @@
 
 #include "libdm/dm_target.h"
 
+#include <stdio.h>
+#include <sys/types.h>
+
 #include <android-base/logging.h>
 #include <android-base/macros.h>
 #include <android-base/parseint.h>
@@ -193,5 +196,30 @@ bool DmTargetSnapshot::ParseStatusText(const std::string& text, Status* status)
     return true;
 }
 
+std::string DmTargetCrypt::GetParameterString() const {
+    std::vector<std::string> argv = {
+            cipher_,
+            key_,
+            std::to_string(iv_sector_offset_),
+            device_,
+            std::to_string(device_sector_),
+    };
+
+    std::vector<std::string> extra_argv;
+    if (allow_discards_) extra_argv.emplace_back("allow_discards");
+    if (allow_encrypt_override_) extra_argv.emplace_back("allow_encrypt_override");
+    if (iv_large_sectors_) extra_argv.emplace_back("iv_large_sectors");
+    if (sector_size_) extra_argv.emplace_back("sector_size:" + std::to_string(sector_size_));
+
+    if (!extra_argv.empty()) argv.emplace_back(std::to_string(extra_argv.size()));
+
+    argv.insert(argv.end(), extra_argv.begin(), extra_argv.end());
+    return android::base::Join(argv, " ");
+}
+
+std::string DmTargetDefaultKey::GetParameterString() const {
+    return cipher_ + " " + key_ + " " + blockdev_ + " " + std::to_string(start_sector_);
+}
+
 }  // namespace dm
 }  // namespace android

fs_mgr/libdm/dm_test.cpp

@@ -438,3 +438,26 @@ TEST(libdm, DmSnapshotOverflow) {
         ASSERT_EQ(status.error, "Invalid");
     }
 }
+
+TEST(libdm, CryptArgs) {
+    DmTargetCrypt target1(0, 512, "sha1", "abcdefgh", 50, "/dev/loop0", 100);
+    ASSERT_EQ(target1.name(), "crypt");
+    ASSERT_TRUE(target1.Valid());
+    ASSERT_EQ(target1.GetParameterString(), "sha1 abcdefgh 50 /dev/loop0 100");
+
+    DmTargetCrypt target2(0, 512, "sha1", "abcdefgh", 50, "/dev/loop0", 100);
+    target2.SetSectorSize(64);
+    target2.AllowDiscards();
+    target2.SetIvLargeSectors();
+    target2.AllowEncryptOverride();
+    ASSERT_EQ(target2.GetParameterString(),
+              "sha1 abcdefgh 50 /dev/loop0 100 4 allow_discards allow_encrypt_override "
+              "iv_large_sectors sector_size:64");
+}
+
+TEST(libdm, DefaultKeyArgs) {
+    DmTargetDefaultKey target(0, 4096, "AES-256-XTS", "abcdef0123456789", "/dev/loop0", 0);
+    ASSERT_EQ(target.name(), "default-key");
+    ASSERT_TRUE(target.Valid());
+    ASSERT_EQ(target.GetParameterString(), "AES-256-XTS abcdef0123456789 /dev/loop0 0");
+}

fs_mgr/libdm/include/libdm/dm_table.h

@@ -43,12 +43,20 @@ class DmTable {
     // successfully removed.
     bool RemoveTarget(std::unique_ptr<DmTarget>&& target);
 
+    // Adds a target, constructing it in-place for convenience. For example,
+    //
+    //   table.Emplace<DmTargetZero>(0, num_sectors);
+    template <typename T, typename... Args>
+    bool Emplace(Args&&... args) {
+        return AddTarget(std::make_unique<T>(std::forward<Args>(args)...));
+    }
+
     // Checks the table to make sure it is valid. i.e. Checks for range overlaps, range gaps
     // and returns 'true' if the table is ready to be loaded into kernel. Returns 'false' if the
     // table is malformed.
     bool valid() const;
 
-    // Returns the toatl number of targets.
+    // Returns the total number of targets.
     size_t num_targets() const { return targets_.size(); }
 
     // Returns the total size represented by the table in terms of number of 512-byte sectors.

fs_mgr/libdm/include/libdm/dm_target.h

@@ -241,6 +241,60 @@ class DmTargetSnapshotOrigin final : public DmTarget {
     std::string device_;
 };
 
+class DmTargetCrypt final : public DmTarget {
+  public:
+    DmTargetCrypt(uint64_t start, uint64_t length, const std::string& cipher,
+                  const std::string& key, uint64_t iv_sector_offset, const std::string& device,
+                  uint64_t device_sector)
+        : DmTarget(start, length),
+          cipher_(cipher),
+          key_(key),
+          iv_sector_offset_(iv_sector_offset),
+          device_(device),
+          device_sector_(device_sector) {}
+
+    void AllowDiscards() { allow_discards_ = true; }
+    void AllowEncryptOverride() { allow_encrypt_override_ = true; }
+    void SetIvLargeSectors() { iv_large_sectors_ = true; }
+    void SetSectorSize(uint32_t sector_size) { sector_size_ = sector_size; }
+
+    std::string name() const override { return "crypt"; }
+    bool Valid() const override { return true; }
+    std::string GetParameterString() const override;
+
+  private:
+    std::string cipher_;
+    std::string key_;
+    uint64_t iv_sector_offset_;
+    std::string device_;
+    uint64_t device_sector_;
+    bool allow_discards_ = false;
+    bool allow_encrypt_override_ = false;
+    bool iv_large_sectors_ = false;
+    uint32_t sector_size_ = 0;
+};
+
+class DmTargetDefaultKey final : public DmTarget {
+  public:
+    DmTargetDefaultKey(uint64_t start, uint64_t length, const std::string& cipher,
+                       const std::string& key, const std::string& blockdev, uint64_t start_sector)
+        : DmTarget(start, length),
+          cipher_(cipher),
+          key_(key),
+          blockdev_(blockdev),
+          start_sector_(start_sector) {}
+
+    std::string name() const override { return "default-key"; }
+    bool Valid() const override { return true; }
+    std::string GetParameterString() const override;
+
+  private:
+    std::string cipher_;
+    std::string key_;
+    std::string blockdev_;
+    uint64_t start_sector_;
+};
+
 }  // namespace dm
 }  // namespace android