Repository: trafficserver
Updated Branches:
  refs/heads/master 2ba2baaa6 -> 374355c01


[TS-2822] Crash in LogBufferIterator::next


Project: http://git-wip-us.apache.org/repos/asf/trafficserver/repo
Commit: http://git-wip-us.apache.org/repos/asf/trafficserver/commit/7c314c5c
Tree: http://git-wip-us.apache.org/repos/asf/trafficserver/tree/7c314c5c
Diff: http://git-wip-us.apache.org/repos/asf/trafficserver/diff/7c314c5c

Branch: refs/heads/master
Commit: 7c314c5c9bfa347fd583500698c2c586f668f7ea
Parents: 2ba2baa
Author: Brian Geffon <[email protected]>
Authored: Wed May 21 09:49:13 2014 -0700
Committer: Brian Geffon <[email protected]>
Committed: Wed May 21 09:49:13 2014 -0700

----------------------------------------------------------------------
 proxy/logstats.cc | 37 +++++++++++++++++++++++++++++++------
 1 file changed, 31 insertions(+), 6 deletions(-)
----------------------------------------------------------------------


http://git-wip-us.apache.org/repos/asf/trafficserver/blob/7c314c5c/proxy/logstats.cc
----------------------------------------------------------------------
diff --git a/proxy/logstats.cc b/proxy/logstats.cc
index 15aeaa2..c6386a6 100644
--- a/proxy/logstats.cc
+++ b/proxy/logstats.cc
@@ -1672,6 +1672,7 @@ parse_log_buff(LogBufferHeader * buf_header, bool summary 
= false)
 int
 process_file(int in_fd, off_t offset, unsigned max_age)
 {
+  ink_release_assert(in_fd < FD_SETSIZE); // If you're exceeding this then use 
CLOSEONEXEC with your opens before FORK/EXEC
   char buffer[MAX_LOGBUFFER_SIZE];
   int nread, buffer_bytes;
 
@@ -1730,7 +1731,7 @@ process_file(int in_fd, off_t offset, unsigned max_age)
     unsigned second_read_size = sizeof(LogBufferHeader) - first_read_size;
     nread = read(in_fd, &buffer[first_read_size], second_read_size);
     if (!nread || EOF == nread) {
-      Debug("logstats", "Second read of header failed (attemped %d bytes at 
offset %d, got nothing).", second_read_size, first_read_size);
+      Debug("logstats", "Second read of header failed (attemped %d bytes at 
offset %d, got nothing), errno=%d.", second_read_size, first_read_size, errno);
       return 1;
     }
 
@@ -1746,11 +1747,35 @@ process_file(int in_fd, off_t offset, unsigned max_age)
       return 1;
     }
 
-    nread = read(in_fd, &buffer[sizeof(LogBufferHeader)], buffer_bytes);
-    if (!nread || EOF == nread) {
-      Debug("logstats", "Failed to read buffer payload [%d bytes]", 
buffer_bytes);
-      return 1;
-    }
+    const int MAX_READ_TRIES = 5;
+    int total_read = 0;
+    int read_tries_remaining = MAX_READ_TRIES; // since the data will be old 
anyway, let's only try a few times.
+    nread = 0;
+    do {
+      nread = read(in_fd, &buffer[sizeof(LogBufferHeader) + total_read], 
buffer_bytes - total_read);
+      if (EOF == nread || !nread) { // just bail on error
+        Debug("logstats", "Read failed while reading log buffer, wanted %d 
bytes, nread=%d, total_read=%d, errno=%d, tries_remaining=%d", buffer_bytes - 
total_read, nread, total_read,
+            errno, read_tries_remaining);
+        return 1;
+      } else {
+        total_read += nread;
+      }
+
+      if (total_read < buffer_bytes) {
+        if (--read_tries_remaining <= 0) {
+          Debug("logstats_failed_retries", "Unable to read after %d tries, 
total_read=%d, buffer_bytes=%d", MAX_READ_TRIES, total_read, buffer_bytes);
+          return 1;
+        }
+        // let's wait until we get more data on this file descriptor
+        Debug("logstats_partial_read", "Failed to read buffer payload [%d 
bytes], total_read=%d, buffer_bytes=%d, tries_remaining=%d",
+            buffer_bytes - total_read, total_read, buffer_bytes, 
read_tries_remaining);
+        fd_set fds;
+        struct timeval tv = {0, 50*1000}; // wait only up to 50ms
+        FD_ZERO(&fds);
+        FD_SET(in_fd, &fds);
+        select(in_fd + 1, &fds, NULL, NULL, &tv);  // we only need to select 
up to in_fd + 1.
+      }
+    } while (total_read < buffer_bytes);
 
     // Possibly skip too old entries (the entire buffer is skipped)
     if (header->high_timestamp >= max_age) {

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