commit 81cc119eff846ccb55af53f80b2ac55a50a0f039
author Konstantin Vyshetsky <vkon@google.com> Thu Nov 04 10:27:06 2021 -0700
committer Konstantin Vyshetsky <vkon@google.com> Thu Nov 04 12:05:48 2021 -0700
tree 2852a0971bb0ff7aa50178630033f862fc7a1ce5
parent 52a213518035d1c826395a6d01f3385088504e11

fastbootd: allow passage of flags to open partition

Allow caller to pass additional flags when opening a partition. Obsolete
usage of boolean read, and make previous callers use O_RDONLY instead.
Explicitly OR (O_EXCL | O_CLOEXEC | O_BINARY) to keep existing design
working as is.

Test: flash locally and reach home screen
Bug: 205151372
Signed-off-by: Konstantin Vyshetsky <vkon@google.com>
Change-Id: I48fbca459a17fcf0b0926ab339585e3bd8e31e35

fastboot/device/commands.cpp

diff --git a/fastboot/device/commands.cpp b/fastboot/device/commands.cpp
index 0a72812..4042531 100644
--- a/fastboot/device/commands.cpp
+++ b/fastboot/device/commands.cpp
@@ -725,7 +725,7 @@
             return false;
         }
 
-        if (!OpenPartition(device_, partition_name_, &handle_, true /* read */)) {
+        if (!OpenPartition(device_, partition_name_, &handle_, O_RDONLY)) {
             ret_ = device_->WriteFail(
                     android::base::StringPrintf("Cannot open %s", partition_name_.c_str()));
             return false;

fastboot/device/utility.cpp

diff --git a/fastboot/device/utility.cpp b/fastboot/device/utility.cpp
index 07ad902..97b5ad4 100644
--- a/fastboot/device/utility.cpp
+++ b/fastboot/device/utility.cpp
@@ -78,7 +78,7 @@
 }  // namespace
 
 bool OpenPartition(FastbootDevice* device, const std::string& name, PartitionHandle* handle,
-                   bool read) {
+                   int flags) {
     // We prioritize logical partitions over physical ones, and do this
     // consistently for other partition operations (like getvar:partition-size).
     if (LogicalPartitionExists(device, name)) {
@@ -90,7 +90,6 @@
         return false;
     }
 
-    int flags = (read ? O_RDONLY : O_WRONLY);
     flags |= (O_EXCL | O_CLOEXEC | O_BINARY);
     unique_fd fd(TEMP_FAILURE_RETRY(open(handle->path().c_str(), flags)));
     if (fd < 0) {

fastboot/device/utility.h

diff --git a/fastboot/device/utility.h b/fastboot/device/utility.h
index c2646d7..1d81b7a 100644
--- a/fastboot/device/utility.h
+++ b/fastboot/device/utility.h
@@ -76,9 +76,11 @@
 bool LogicalPartitionExists(FastbootDevice* device, const std::string& name,
                             bool* is_zero_length = nullptr);
 
-// If read, partition is readonly. Else it is write only.
+// Partition is O_WRONLY by default, caller should pass O_RDONLY for reading.
+// Caller may pass additional flags if needed. (O_EXCL | O_CLOEXEC | O_BINARY)
+// will be logically ORed internally.
 bool OpenPartition(FastbootDevice* device, const std::string& name, PartitionHandle* handle,
-                   bool read = false);
+                   int flags = O_WRONLY);
 
 bool GetSlotNumber(const std::string& slot, android::hardware::boot::V1_0::Slot* number);
 std::vector<std::string> ListPartitions(FastbootDevice* device);