update_engine: added partition name manipulation library methods
Added utility methods to split and merge partition device names
to help "semi-intelligently" break down full partition device
name into disk name and partition name and merge them back.
With special handling for MMC devices and similar.
Also removed inconsistent naming for the disk and partition
device names (such as "boot device", "root device", etc).
Now device names such as "/dev/sda" are referred to as
"disk name" and "/dev/sda1" as "partition name").
BUG=None
TEST=Updated and ran unit tests
Change-Id: Ica41b8c99f0120799be326af0b41324639c5cf6a
Reviewed-on: https://chromium-review.googlesource.com/187453
Commit-Queue: Alex Vakulenko <avakulenko@chromium.org>
Tested-by: Alex Vakulenko <avakulenko@chromium.org>
Reviewed-by: Don Garrett <dgarrett@chromium.org>
diff --git a/utils.cc b/utils.cc
index 8a73cd7..7558f35 100644
--- a/utils.cc
+++ b/utils.cc
@@ -368,31 +368,78 @@
return true;
}
-string RootDevice(const string& partition_device) {
- FilePath device_path(partition_device);
- if (device_path.DirName().value() != "/dev") {
- return "";
- }
- string::const_iterator it = --partition_device.end();
- for (; it >= partition_device.begin(); --it) {
- if (!isdigit(*it))
- break;
- }
- // Some devices contain a p before the partitions. For example:
- // /dev/mmc0p4 should be shortened to /dev/mmc0.
- if (*it == 'p')
- --it;
- return string(partition_device.begin(), it + 1);
+std::string GetDiskName(const string& partition_name) {
+ std::string disk_name;
+ return SplitPartitionName(partition_name, &disk_name, nullptr) ?
+ disk_name : std::string();
}
-string PartitionNumber(const string& partition_device) {
- CHECK(!partition_device.empty());
- string::const_iterator it = --partition_device.end();
- for (; it >= partition_device.begin(); --it) {
- if (!isdigit(*it))
- break;
+int GetPartitionNumber(const std::string& partition_name) {
+ int partition_num = 0;
+ return SplitPartitionName(partition_name, nullptr, &partition_num) ?
+ partition_num : 0;
+}
+
+bool SplitPartitionName(const std::string& partition_name,
+ std::string* out_disk_name,
+ int* out_partition_num) {
+ if (!StringHasPrefix(partition_name, "/dev/")) {
+ LOG(ERROR) << "Invalid partition device name: " << partition_name;
+ return false;
}
- return string(it + 1, partition_device.end());
+
+ if (StringHasPrefix(partition_name, "/dev/ubiblock")) {
+ // NAND block devices have weird naming which could be something
+ // like "/dev/ubiblock2_0". Since update engine doesn't have proper
+ // support for NAND devices yet, don't bother parsing their names for now.
+ LOG(ERROR) << "UBI block devices are not supported: " << partition_name;
+ return false;
+ }
+
+ size_t pos = partition_name.find_last_not_of("0123456789");
+ if (pos == string::npos || (pos + 1) == partition_name.size()) {
+ LOG(ERROR) << "Unable to parse partition device name: "
+ << partition_name;
+ return false;
+ }
+
+ if (out_disk_name) {
+ // Special case for MMC devices which have the following naming scheme:
+ // mmcblk0p2
+ bool valid_mmc_device = StringHasPrefix(partition_name, "/dev/mmcblk") &&
+ partition_name[pos] == 'p';
+ *out_disk_name =
+ partition_name.substr(0, valid_mmc_device ? pos : (pos + 1));
+ }
+
+ if (out_partition_num) {
+ std::string partition_str = partition_name.substr(pos + 1);
+ *out_partition_num = atoi(partition_str.c_str());
+ }
+ return true;
+}
+
+std::string MakePartitionName(const std::string& disk_name,
+ int partition_num) {
+ if (!StringHasPrefix(disk_name, "/dev/")) {
+ LOG(ERROR) << "Invalid disk name: " << disk_name;
+ return std::string();
+ }
+
+ if (partition_num < 1) {
+ LOG(ERROR) << "Invalid partition number: " << partition_num;
+ return std::string();
+ }
+
+ std::string partition_name = disk_name;
+ if (!StringHasPrefix(disk_name, "/dev/mmcblk")) {
+ // Special case for MMC devices. Add "p" to separate the disk name
+ // from partition number
+ partition_name += 'p';
+ }
+
+ base::StringAppendF(&partition_name, "%d", partition_num);
+ return partition_name;
}
string SysfsBlockDevice(const string& device) {