Merge "Keep reading until end-of-file in reading procfs" into main
diff --git a/core/jni/android_util_Process.cpp b/core/jni/android_util_Process.cpp
index 982189e..1a1d83c 100644
--- a/core/jni/android_util_Process.cpp
+++ b/core/jni/android_util_Process.cpp
@@ -1063,8 +1063,8 @@
}
env->ReleaseStringUTFChars(file, file8);
- // Most proc files we read are small, so we only go through the
- // loop once and use the stack buffer. We allocate a buffer big
+ // Most proc files we read are small, so we go through the loop
+ // with the stack buffer firstly. We allocate a buffer big
// enough for the whole file.
char readBufferStack[kProcReadStackBufferSize];
@@ -1072,37 +1072,47 @@
char* readBuffer = &readBufferStack[0];
ssize_t readBufferSize = kProcReadStackBufferSize;
ssize_t numberBytesRead;
+ off_t offset = 0;
for (;;) {
+ ssize_t requestedBufferSize = readBufferSize - offset;
// By using pread, we can avoid an lseek to rewind the FD
// before retry, saving a system call.
- numberBytesRead = pread(fd, readBuffer, readBufferSize, 0);
- if (numberBytesRead < 0 && errno == EINTR) {
- continue;
- }
+ numberBytesRead =
+ TEMP_FAILURE_RETRY(pread(fd, readBuffer + offset, requestedBufferSize, offset));
if (numberBytesRead < 0) {
if (kDebugProc) {
- ALOGW("Unable to open process file: %s fd=%d\n", file8, fd.get());
+ ALOGW("Unable to read process file err: %s file: %s fd=%d\n",
+ strerror_r(errno, &readBufferStack[0], sizeof(readBufferStack)), file8,
+ fd.get());
}
return JNI_FALSE;
}
- if (numberBytesRead < readBufferSize) {
+ if (numberBytesRead == 0) {
+ // End of file.
+ numberBytesRead = offset;
break;
}
- if (readBufferSize > std::numeric_limits<ssize_t>::max() / 2) {
- if (kDebugProc) {
- ALOGW("Proc file too big: %s fd=%d\n", file8, fd.get());
+ if (numberBytesRead < requestedBufferSize) {
+ // Read less bytes than requested, it's not an error per pread(2).
+ offset += numberBytesRead;
+ } else {
+ // Buffer is fully used, try to grow it.
+ if (readBufferSize > std::numeric_limits<ssize_t>::max() / 2) {
+ if (kDebugProc) {
+ ALOGW("Proc file too big: %s fd=%d\n", file8, fd.get());
+ }
+ return JNI_FALSE;
}
- return JNI_FALSE;
+ readBufferSize = std::max(readBufferSize * 2, kProcReadMinHeapBufferSize);
+ readBufferHeap.reset(); // Free address space before getting more.
+ readBufferHeap = std::make_unique<char[]>(readBufferSize);
+ if (!readBufferHeap) {
+ jniThrowException(env, "java/lang/OutOfMemoryError", NULL);
+ return JNI_FALSE;
+ }
+ readBuffer = readBufferHeap.get();
+ offset = 0;
}
- readBufferSize = std::max(readBufferSize * 2,
- kProcReadMinHeapBufferSize);
- readBufferHeap.reset(); // Free address space before getting more.
- readBufferHeap = std::make_unique<char[]>(readBufferSize);
- if (!readBufferHeap) {
- jniThrowException(env, "java/lang/OutOfMemoryError", NULL);
- return JNI_FALSE;
- }
- readBuffer = readBufferHeap.get();
}
// parseProcLineArray below modifies the buffer while parsing!