From: Amos Jeffries <squid3@treenet.co.nz>
Date: Tue, 11 Nov 2014 13:37:41 +0000 (-0800)
Subject: Allow limiting of read(2) operations in SBuf I/O API
X-Git-Tag: merge-candidate-3-v1~240^2~19
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=983de17ba395ac4366eac1fe2dbce8eb7694aba5;p=thirdparty%2Fsquid.git

Allow limiting of read(2) operations in SBuf I/O API

If params.size is non-zero limit size of the read to either the buffer
free space or params.size, whichever is smallest.
---

diff --git a/src/comm/Read.cc b/src/comm/Read.cc
index b881adc5ad..58d2c8d864 100644
--- a/src/comm/Read.cc
+++ b/src/comm/Read.cc
@@ -82,7 +82,9 @@ Comm::ReadNow(CommIoCbParams &params, SBuf &buf)
 {
     /* Attempt a read */
     ++ statCounter.syscalls.sock.reads;
-    const SBuf::size_type sz = buf.spaceSize();
+    SBuf::size_type sz = buf.spaceSize();
+    if (params.size > 0 && params.size < sz)
+        sz = params.size;
     char *inbuf = buf.rawSpace(sz);
     errno = 0;
     const int retval = FD_READ_METHOD(params.conn->fd, inbuf, sz);
diff --git a/src/comm/Read.h b/src/comm/Read.h
index 90cb7560fd..dfc7823735 100644
--- a/src/comm/Read.h
+++ b/src/comm/Read.h
@@ -32,6 +32,9 @@ bool MonitorsRead(int fd);
 /**
  * Perform a read(2) on a connection immediately.
  *
+ * If params.size is non-zero will limit size of the read to either
+ * the buffer free space or params.size, whichever is smallest.
+ *
  * The returned flag is also placed in params.flag.
  *
  * \retval Comm::OK          data has been read and placed in buf, amount in params.size