Add timeout for dump_file.

It turns out dump_file is used on a number of /proc and system files.
In one case, the read of a file stalled and caused a bugreport to
hang forever. It's still possible if there is a kernel bug that this
could stall forever, but less likely.

Also, change the return type of nanotime to uint64_t.

Testing:
- Created a named fifo and verified that dump_file fails with a timeout.
- Created a large /data/anr/traces.txt to verify that large files still
  dump properly and that the additional NONBLOCK parameter doesn't cause
  a problem.
- Created a dummy /data/tombstones/tombstone_00 to verify that the
  dump of these files still works.
- Compared a dump using the old dumpstate to the new dumpstate to verify
  nothing obviously different.

Bug: 19117030
Change-Id: I0d3dd27583c853cdaccd2fd278748cb5f9ccd4fb
diff --git a/cmds/dumpstate/dumpstate.c b/cmds/dumpstate/dumpstate.c
index 1d33d71..3ed54c3 100644
--- a/cmds/dumpstate/dumpstate.c
+++ b/cmds/dumpstate/dumpstate.c
@@ -63,7 +63,8 @@
     time_t thirty_minutes_ago = time(NULL) - 60*30;
     for (size_t i = 0; i < NUM_TOMBSTONES; i++) {
         snprintf(data[i].name, sizeof(data[i].name), "%s%02zu", TOMBSTONE_FILE_PREFIX, i);
-        int fd = open(data[i].name, O_RDONLY | O_CLOEXEC | O_NOFOLLOW);
+        int fd = TEMP_FAILURE_RETRY(open(data[i].name,
+                                         O_RDONLY | O_CLOEXEC | O_NOFOLLOW | O_NONBLOCK));
         struct stat st;
         if (fstat(fd, &st) == 0 && S_ISREG(st.st_mode) &&
                 (time_t) st.st_mtime >= thirty_minutes_ago) {
@@ -159,7 +160,8 @@
     if (!anr_traces_path[0]) {
         printf("*** NO VM TRACES FILE DEFINED (dalvik.vm.stack-trace-file)\n\n");
     } else {
-      int fd = open(anr_traces_path, O_RDONLY | O_CLOEXEC | O_NOFOLLOW);
+      int fd = TEMP_FAILURE_RETRY(open(anr_traces_path,
+                                       O_RDONLY | O_CLOEXEC | O_NOFOLLOW | O_NONBLOCK));
       if (fd < 0) {
           printf("*** NO ANR VM TRACES FILE (%s): %s\n\n", anr_traces_path, strerror(errno));
       } else {