Merge changes from topic "lpdumpd"

* changes:
  libbase: realpath is wrapped with TEMP_FAILURE_RETRY
  liblp: Replace open with GetControlFileOrOpen
  init: expand prop in 'file'
  libcutils: android_get_control_file uses realpath.

base/file.cpp

@@ -385,7 +385,12 @@ bool Readlink(const std::string& path, std::string* result) {
 bool Realpath(const std::string& path, std::string* result) {
   result->clear();
 
-  char* realpath_buf = realpath(path.c_str(), nullptr);
+  // realpath may exit with EINTR. Retry if so.
+  char* realpath_buf = nullptr;
+  do {
+    realpath_buf = realpath(path.c_str(), nullptr);
+  } while (realpath_buf == nullptr && errno == EINTR);
+
   if (realpath_buf == nullptr) {
     return false;
   }

fs_mgr/liblp/Android.bp

@@ -43,6 +43,11 @@ cc_library {
         windows: {
             enabled: true,
         },
+        android: {
+            shared_libs: [
+                "libcutils",
+            ],
+        },
     },
     export_include_dirs: ["include"],
 }

fs_mgr/liblp/images.cpp

@@ -68,7 +68,7 @@ std::unique_ptr<LpMetadata> ReadFromImageBlob(const void* data, size_t bytes) {
 }
 
 std::unique_ptr<LpMetadata> ReadFromImageFile(const std::string& image_file) {
-    unique_fd fd(open(image_file.c_str(), O_RDONLY | O_CLOEXEC));
+    unique_fd fd = GetControlFileOrOpen(image_file.c_str(), O_RDONLY | O_CLOEXEC);
     if (fd < 0) {
         PERROR << __PRETTY_FUNCTION__ << " open failed: " << image_file;
         return nullptr;
@@ -408,7 +408,7 @@ bool SparseBuilder::CheckExtentOrdering() {
 }
 
 int SparseBuilder::OpenImageFile(const std::string& file) {
-    android::base::unique_fd source_fd(open(file.c_str(), O_RDONLY | O_CLOEXEC));
+    android::base::unique_fd source_fd = GetControlFileOrOpen(file.c_str(), O_RDONLY | O_CLOEXEC);
     if (source_fd < 0) {
         PERROR << "open image file failed: " << file;
         return -1;

fs_mgr/liblp/partition_opener.cpp

@@ -45,7 +45,7 @@ std::string GetPartitionAbsolutePath(const std::string& path) {
 
 bool GetBlockDeviceInfo(const std::string& block_device, BlockDeviceInfo* device_info) {
 #if defined(__linux__)
-    unique_fd fd(open(block_device.c_str(), O_RDONLY));
+    unique_fd fd = GetControlFileOrOpen(block_device.c_str(), O_RDONLY);
     if (fd < 0) {
         PERROR << __PRETTY_FUNCTION__ << "open '" << block_device << "' failed";
         return false;
@@ -85,7 +85,7 @@ bool GetBlockDeviceInfo(const std::string& block_device, BlockDeviceInfo* device
 
 unique_fd PartitionOpener::Open(const std::string& partition_name, int flags) const {
     std::string path = GetPartitionAbsolutePath(partition_name);
-    return unique_fd{open(path.c_str(), flags | O_CLOEXEC)};
+    return GetControlFileOrOpen(path.c_str(), flags | O_CLOEXEC);
 }
 
 bool PartitionOpener::GetInfo(const std::string& partition_name, BlockDeviceInfo* info) const {

fs_mgr/liblp/utility.cpp

@@ -28,6 +28,10 @@
 #include <ext4_utils/ext4_utils.h>
 #include <openssl/sha.h>
 
+#ifdef __ANDROID__
+#include <cutils/android_get_control_file.h>
+#endif
+
 #include "utility.h"
 
 namespace android {
@@ -171,5 +175,19 @@ bool SetBlockReadonly(int fd, bool readonly) {
 #endif
 }
 
+base::unique_fd GetControlFileOrOpen(const char* path, int flags) {
+#if defined(__ANDROID__)
+    int fd = android_get_control_file(path);
+    if (fd >= 0) {
+        int newfd = TEMP_FAILURE_RETRY(dup(fd));
+        if (newfd >= 0) {
+            return base::unique_fd(newfd);
+        }
+        PERROR << "Cannot dup fd for already controlled file: " << path << ", reopening...";
+    }
+#endif
+    return base::unique_fd(open(path, flags));
+}
+
 }  // namespace fs_mgr
 }  // namespace android

fs_mgr/liblp/utility.h

@@ -22,6 +22,7 @@
 #include <sys/types.h>
 
 #include <android-base/logging.h>
+#include <android-base/unique_fd.h>
 
 #include "liblp/liblp.h"
 
@@ -92,6 +93,8 @@ bool UpdatePartitionGroupName(LpMetadataPartitionGroup* group, const std::string
 // Call BLKROSET ioctl on fd so that fd is readonly / read-writable.
 bool SetBlockReadonly(int fd, bool readonly);
 
+::android::base::unique_fd GetControlFileOrOpen(const char* path, int flags);
+
 }  // namespace fs_mgr
 }  // namespace android
 

init/service.cpp

@@ -756,6 +756,11 @@ Result<Success> Service::ParseFile(std::vector<std::string>&& args) {
     if (args[2] != "r" && args[2] != "w" && args[2] != "rw") {
         return Error() << "file type must be 'r', 'w' or 'rw'";
     }
+    std::string expanded;
+    if (!expand_props(args[1], &expanded)) {
+        return Error() << "Could not expand property in file path '" << args[1] << "'";
+    }
+    args[1] = std::move(expanded);
     if ((args[1][0] != '/') || (args[1].find("../") != std::string::npos)) {
         return Error() << "file name must not be relative";
     }

libcutils/android_get_control_file.cpp

@@ -39,6 +39,11 @@
 #include <sys/types.h>
 #include <unistd.h>
 
+#include <string>
+
+#include <android-base/file.h>
+#include <android-base/stringprintf.h>
+
 #include "android_get_control_env.h"
 
 int __android_get_control_from_env(const char* prefix, const char* name) {
@@ -72,26 +77,22 @@ int __android_get_control_from_env(const char* prefix, const char* name) {
 }
 
 int android_get_control_file(const char* path) {
-    int fd = __android_get_control_from_env(ANDROID_FILE_ENV_PREFIX, path);
+    std::string given_path;
+    if (!android::base::Realpath(path, &given_path)) return -1;
+
+    // Try path, then realpath(path), as keys to get the fd from env.
+    auto fd = __android_get_control_from_env(ANDROID_FILE_ENV_PREFIX, path);
+    if (fd < 0) {
+        fd = __android_get_control_from_env(ANDROID_FILE_ENV_PREFIX, given_path.c_str());
+        if (fd < 0) return fd;
+    }
 
     // Find file path from /proc and make sure it is correct
-    char *proc = NULL;
-    if (asprintf(&proc, "/proc/self/fd/%d", fd) < 0) return -1;
-    if (!proc) return -1;
+    auto proc = android::base::StringPrintf("/proc/self/fd/%d", fd);
+    std::string fd_path;
+    if (!android::base::Realpath(proc, &fd_path)) return -1;
 
-    size_t len = strlen(path);
-    // readlink() does not guarantee a nul byte, len+2 so we catch truncation.
-    char *buf = static_cast<char *>(calloc(1, len + 2));
-    if (!buf) {
-        free(proc);
-        return -1;
-    }
-    ssize_t ret = TEMP_FAILURE_RETRY(readlink(proc, buf, len + 1));
-    free(proc);
-    int cmp = (len != static_cast<size_t>(ret)) || strcmp(buf, path);
-    free(buf);
-    if (ret < 0) return -1;
-    if (cmp != 0) return -1;
+    if (given_path != fd_path) return -1;
     // It is what we think it is
 
     return fd;