Merge "ReadDmaBufFdRefs: Log once permission denials" am: f5b9581b9a am: 9c8a5025a9 am: b59ee15e6f
Original change: https://android-review.googlesource.com/c/platform/system/memory/libmeminfo/+/1668525
Change-Id: I96a8f8d95fa86c02e472d7b17f4124d4a1108864
diff --git a/libdmabufinfo/dmabufinfo.cpp b/libdmabufinfo/dmabufinfo.cpp
index 111a5ac..a0fc9da 100644
--- a/libdmabufinfo/dmabufinfo.cpp
+++ b/libdmabufinfo/dmabufinfo.cpp
@@ -45,9 +45,9 @@
}
enum FdInfoResult {
- OK,
- NOT_FOUND,
- ERROR,
+ OK,
+ NOT_FOUND,
+ ERROR,
};
static FdInfoResult ReadDmaBufFdInfo(pid_t pid, int fd, std::string* name, std::string* exporter,
@@ -58,7 +58,7 @@
auto fp = std::unique_ptr<FILE, decltype(&fclose)>{fopen(fdinfo.c_str(), "re"), fclose};
if (fp == nullptr) {
if (errno == ENOENT) {
- return NOT_FOUND;
+ return NOT_FOUND;
}
PLOG(ERROR) << "Failed to open " << fdinfo;
return ERROR;
@@ -109,11 +109,23 @@
// Public methods
bool ReadDmaBufFdRefs(int pid, std::vector<DmaBuffer>* dmabufs,
const std::string& procfs_path) {
+ constexpr char permission_err_msg[] =
+ "Failed to read fdinfo - requires either PTRACE_MODE_READ or root depending on "
+ "the device kernel";
+ static bool logged_permission_err = false;
+
std::string fdinfo_dir_path =
::android::base::StringPrintf("%s/%d/fdinfo", procfs_path.c_str(), pid);
std::unique_ptr<DIR, decltype(&closedir)> dir(opendir(fdinfo_dir_path.c_str()), &closedir);
if (!dir) {
- PLOG(ERROR) << "Failed to open " << fdinfo_dir_path << " directory";
+ // Don't log permission errors to reduce log spam on devices where fdinfo
+ // of other processes can only be read by root.
+ if (errno != EACCES) {
+ PLOG(ERROR) << "Failed to open " << fdinfo_dir_path << " directory";
+ } else if (!logged_permission_err) {
+ LOG(ERROR) << permission_err_msg;
+ logged_permission_err = true;
+ }
return false;
}
struct dirent* dent;
@@ -136,9 +148,16 @@
&is_dmabuf_file, procfs_path);
if (fdinfo_result != OK) {
if (fdinfo_result == NOT_FOUND) {
- continue;
+ continue;
}
- LOG(ERROR) << "Failed to read fd info for pid: " << pid << ", fd: " << fd;
+ // Don't log permission errors to reduce log spam when the process doesn't
+ // have the PTRACE_MODE_READ permission.
+ if (errno != EACCES) {
+ LOG(ERROR) << "Failed to read fd info for pid: " << pid << ", fd: " << fd;
+ } else if (!logged_permission_err) {
+ LOG(ERROR) << permission_err_msg;
+ logged_permission_err = true;
+ }
return false;
}
if (!is_dmabuf_file) {
