updater: Add "write_value()" function.
write_value(value, filename) writes 'value' to 'filename'. It can be
used to tune device settings when applying an OTA package. For example,
write_value("960000", "/sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq").
Bug: 32463933
Test: recovery_component_test passes.
Test: Apply an OTA package that contains a call to write_value(), and
check the result.
Change-Id: Ib009ecb8a45a94353f10c59e2383fe1f49796e35
diff --git a/tests/component/updater_test.cpp b/tests/component/updater_test.cpp
index a029cf4..d34c0e5 100644
--- a/tests/component/updater_test.cpp
+++ b/tests/component/updater_test.cpp
@@ -322,3 +322,36 @@
CloseArchive(handle);
}
+
+TEST_F(UpdaterTest, write_value) {
+ // write_value() expects two arguments.
+ expect(nullptr, "write_value()", kArgsParsingFailure);
+ expect(nullptr, "write_value(\"arg1\")", kArgsParsingFailure);
+ expect(nullptr, "write_value(\"arg1\", \"arg2\", \"arg3\")", kArgsParsingFailure);
+
+ // filename cannot be empty.
+ expect(nullptr, "write_value(\"value\", \"\")", kArgsParsingFailure);
+
+ // Write some value to file.
+ TemporaryFile temp_file;
+ std::string value = "magicvalue";
+ std::string script("write_value(\"" + value + "\", \"" + std::string(temp_file.path) + "\")");
+ expect("t", script.c_str(), kNoCause);
+
+ // Verify the content.
+ std::string content;
+ ASSERT_TRUE(android::base::ReadFileToString(temp_file.path, &content));
+ ASSERT_EQ(value, content);
+
+ // Allow writing empty string.
+ script = "write_value(\"\", \"" + std::string(temp_file.path) + "\")";
+ expect("t", script.c_str(), kNoCause);
+
+ // Verify the content.
+ ASSERT_TRUE(android::base::ReadFileToString(temp_file.path, &content));
+ ASSERT_EQ("", content);
+
+ // It should fail gracefully when write fails.
+ script = "write_value(\"value\", \"/proc/0/file1\")";
+ expect("", script.c_str(), kNoCause);
+}
diff --git a/updater/install.cpp b/updater/install.cpp
index b885f86..da68420 100644
--- a/updater/install.cpp
+++ b/updater/install.cpp
@@ -39,11 +39,12 @@
#include <string>
#include <vector>
-#include <android-base/parseint.h>
+#include <android-base/file.h>
#include <android-base/parsedouble.h>
+#include <android-base/parseint.h>
#include <android-base/properties.h>
-#include <android-base/strings.h>
#include <android-base/stringprintf.h>
+#include <android-base/strings.h>
#include <cutils/android_reboot.h>
#include <ext4_utils/make_ext4fs.h>
#include <ext4_utils/wipe.h>
@@ -861,7 +862,6 @@
return StringValue(value);
}
-
// file_getprop(file, key)
//
// interprets 'file' as a getprop-style file (key=value pairs, one
@@ -1155,6 +1155,33 @@
return v;
}
+// write_value(value, filename)
+// Writes 'value' to 'filename'.
+// Example: write_value("960000", "/sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq")
+Value* WriteValueFn(const char* name, State* state, int argc, Expr* argv[]) {
+ if (argc != 2) {
+ return ErrorAbort(state, kArgsParsingFailure, "%s() expects 2 args, got %d", name, argc);
+ }
+
+ std::vector<std::string> args;
+ if (!ReadArgs(state, 2, argv, &args)) {
+ return ErrorAbort(state, kArgsParsingFailure, "%s(): Failed to parse the argument(s)", name);
+ }
+
+ const std::string& filename = args[1];
+ if (filename.empty()) {
+ return ErrorAbort(state, kArgsParsingFailure, "%s(): Filename cannot be empty", name);
+ }
+
+ const std::string& value = args[0];
+ if (!android::base::WriteStringToFile(value, filename)) {
+ printf("%s: Failed to write to \"%s\": %s\n", name, filename.c_str(), strerror(errno));
+ return StringValue("");
+ } else {
+ return StringValue("t");
+ }
+}
+
// Immediately reboot the device. Recovery is not finished normally,
// so if you reboot into recovery it will re-start applying the
// current package (because nothing has cleared the copy of the
@@ -1363,6 +1390,7 @@
RegisterFunction("read_file", ReadFileFn);
RegisterFunction("sha1_check", Sha1CheckFn);
RegisterFunction("rename", RenameFn);
+ RegisterFunction("write_value", WriteValueFn);
RegisterFunction("wipe_cache", WipeCacheFn);