postfix-2.10-20120715

diff --git a/postfix/HISTORY b/postfix/HISTORY
index 3058d8fb6af7883e853273f7e5b2e6c387f907fa..afd04e7e71728917c827915b5b9117ee5cb269fc 100644 (file)
--- a/postfix/HISTORY
+++ b/postfix/HISTORY
@@ -17894,3 +17894,10 @@ Apologies for any names omitted.
        Bugfix (introduced: 20120527-8): infrastructure to specify
        a smaller-than-default VSTREAM buffer, without the complex
        run-time checks. File: util/vstream.c, vstream_tweak.c.
+
+20120714
+
+       Cleanup: semantics of requests to query or modify the VSTREAM
+       buffer size that will be used with the next read(2) or
+       write(2) operation. Files: util/vstream.c, util/vstream.h,
+       util/vstream_tweak.c.

diff --git a/postfix/src/global/mail_version.h b/postfix/src/global/mail_version.h
index 965b8a07f84d92acf50f7afa292327f9fff074c5..07549b29f1759cbbbc065046c330ba756f73344a 100644 (file)
--- a/postfix/src/global/mail_version.h
+++ b/postfix/src/global/mail_version.h
@@ -20,7 +20,7 @@
   * Patches change both the patchlevel and the release date. Snapshots have no
   * patchlevel; they change the release date only.
   */
-#define MAIL_RELEASE_DATE      "20120713"
+#define MAIL_RELEASE_DATE      "20120715"
 #define MAIL_VERSION_NUMBER    "2.10"
 
 #ifdef SNAPSHOT

diff --git a/postfix/src/util/vstream.c b/postfix/src/util/vstream.c
index 7a7b7dbcb36fc75028c5de1b717b1093f44e0500..2918a4d1664fb7efa14d6f7f8dd13bcf3a076e35 100644 (file)
--- a/postfix/src/util/vstream.c
+++ b/postfix/src/util/vstream.c
@@ -24,7 +24,7 @@
 /*     VSTREAM *vstream_printf(format, ...)
 /*     const char *format;
 /*
-/*     VSTREAM *vstream_fprintf(stream, format, ...)
+/*     VSTREAM *vstream_fprintf(stream, format, ...)
 /*     VSTREAM *stream;
 /*     const char *format;
 /*
@@ -40,7 +40,7 @@
 /*     int     ch;
 /*
 /*     int     vstream_ungetc(stream, ch)
-/*     VSTREAM *stream;
+/*     VSTREAM *stream;
 /*     int     ch;
 /*
 /*     int     vstream_fputs(str, stream)
@@ -60,7 +60,7 @@
 /*
 /*     int     vstream_fpurge(stream, direction)
 /*     VSTREAM *stream;
-/*     int     direction;
+/*     int     direction;
 /*
 /*     ssize_t vstream_fread(stream, buf, len)
 /*     VSTREAM *stream;
@@ -80,10 +80,10 @@
 /*     VSTREAM *stream;
 /*
 /*     const ssize_t vstream_req_bufsize(stream)
-/*     VSTREAM *stream;
+/*     VSTREAM *stream;
 /*
 /*     void    *vstream_context(stream)
-/*     VSTREAM *stream;
+/*     VSTREAM *stream;
 /*
 /*     int     vstream_ferror(stream)
 /*     VSTREAM *stream;
@@ -324,18 +324,15 @@
 /*     This involves allocation of additional memory that normally isn't
 /*     used.
 /* .IP "VSTREAM_CTL_BUFSIZE (ssize_t)"
-/*     Specify a non-default write buffer size, or zero to implement
-/*     a no-op. Requests to shrink an existing buffer size are
-/*     silently ignored. To get a buffer size smaller than
-/*     VSTREAM_BUFSIZE, make the VSTREAM_CTL_BUFSIZE before the
-/*     stream has been used. Requests to change a fixed-size buffer
-/*     (e.g., stderr) are not allowed.
-/*
-/*     NOTE: the VSTREAM_CTL_BUFSIZE request specifies intent, not
-/*     reality.  Actual buffer sizes are not updated immediately.
-/*     Instead, an existing write buffer will be resized when it
-/*     is full, and an existing read buffer will be resized when
-/*     the buffer is filled.
+/*     Specify a non-default buffer size for the next read(2) or
+/*     write(2) operation, or zero to implement a no-op. Requests
+/*     to reduce the buffer size are silently ignored (i.e. any
+/*     positive value <= vstream_req_bufsize()). To get a buffer
+/*     size smaller than VSTREAM_BUFSIZE, make the VSTREAM_CTL_BUFSIZE
+/*     request before the first stream read or write operation
+/*     (i.e., vstream_req_bufsize() returns zero).  Requests to
+/*     change a fixed-size buffer (i.e., VSTREAM_ERR) are not
+/*     allowed.
 /*
 /*     NOTE: the vstream_*printf() routines may silently expand a
 /*     buffer, so that the result of some %letter specifiers can
@@ -358,13 +355,10 @@
 /*     a buffered stream. With streams that have separate read/write
 /*     file descriptors, the result is the current descriptor.
 /*
-/*     vstream_req_bufsize() returns the requested buffer size for
-/*     the named stream (default: VSTREAM_BUFSIZE). The result
-/*     value reflects intent, not reality: actual buffer sizes are
-/*     not updated immediately when the requested buffer size is
-/*     specified with vstream_control().  Instead, an existing
-/*     write buffer will be resized when it is full, and an existing
-/*     read buffer will be resized when the buffer is filled.
+/*     vstream_req_bufsize() returns the buffer size that will be
+/*     used for the next read(2) or write(2) operation on the named
+/*     stream. A zero result means that the next read(2) or write(2)
+/*     operation will use the default buffer size (VSTREAM_BUFSIZE).
 /*
 /*     vstream_context() returns the application context that is passed on to
 /*     the application-specified read/write routines.
@@ -848,7 +842,7 @@ static int vstream_buf_get_ready(VBUF *bp)
      * allocation gives the application a chance to override the default
      * buffering policy.
      * 
-     * XXX Tricky code to set the preferred buffer size as late as possible.
+     * XXX Subtle code to set the preferred buffer size as late as possible.
      */
     if (stream->req_bufsize == 0)
        stream->req_bufsize = VSTREAM_BUFSIZE;
@@ -960,7 +954,7 @@ static int vstream_buf_put_ready(VBUF *bp)
      * new buffer; obviously there is no data to be flushed yet. Otherwise,
      * flush the buffer.
      * 
-     * XXX Tricky code to set the preferred buffer size as late as possible.
+     * XXX Subtle code to set the preferred buffer size as late as possible.
      */
     if (stream->req_bufsize == 0)
        stream->req_bufsize = VSTREAM_BUFSIZE;
@@ -1015,7 +1009,7 @@ static int vstream_buf_space(VBUF *bp, ssize_t want)
      * VSTREAM_BUFSIZE. We flush multiples of VSTREAM_BUFSIZE in an attempt
      * to keep file updates block-aligned for better performance.
      * 
-     * XXX Tricky code to set the preferred buffer size as late as possible.
+     * XXX Subtle code to set the preferred buffer size as late as possible.
      */
 #define VSTREAM_TRUNCATE(count, base)  (((count) / (base)) * (base))
 #define VSTREAM_ROUNDUP(count, base)   VSTREAM_TRUNCATE(count + base - 1, base)
@@ -1486,9 +1480,15 @@ void    vstream_control(VSTREAM *stream, int name,...)
            if (req_bufsize < 0 || req_bufsize > INT_MAX)
                msg_panic("unreasonable VSTREAM_CTL_BUFSIZE request: %ld",
                          (long) req_bufsize);
-           if (stream != VSTREAM_ERR
-               && req_bufsize > stream->req_bufsize)
+           if ((stream->buf.flags & VSTREAM_FLAG_FIXED) == 0
+               && req_bufsize > stream->req_bufsize) {
+               if (msg_verbose)
+                   msg_info("fd=%d: stream buffer size old=%ld new=%ld",
+                            vstream_fileno(stream),
+                            (long) stream->req_bufsize,
+                            (long) req_bufsize);
                stream->req_bufsize = req_bufsize;
+           }
            break;
 
            /*

diff --git a/postfix/src/util/vstream_tweak.c b/postfix/src/util/vstream_tweak.c
index 5c528376a6df859a01e15e354eb05df391168e20..78c8bd53c0b22349c1affe789d9519352471e083 100644 (file)
--- a/postfix/src/util/vstream_tweak.c
+++ b/postfix/src/util/vstream_tweak.c
@@ -116,12 +116,20 @@ int     vstream_tweak_tcp(VSTREAM *fp)
 
     /*
      * Fix for recent Postfix versions: increase the VSTREAM buffer size if
-     * the default VSTREAM buffer size is smaller than the MSS. Note: the MSS
-     * may change when the route changes and IP path MTU discovery is turned
-     * on, so we choose a somewhat larger buffer.
+     * it is smaller than the MSS. Note: the MSS may change when the route
+     * changes and IP path MTU discovery is turned on, so we choose a
+     * somewhat larger buffer.
+     * 
+     * Note: as of 20120527, the VSTREAM_CTL_BUFSIZE request can reduce the
+     * stream buffer size to less than VSTREAM_BUFSIZE, when the request is
+     * made before the first stream read or write operation. We don't want to
+     * reduce the buffer size.
      */
+#define EFF_BUFFER_SIZE(fp) (vstream_req_bufsize(fp) ? \
+               vstream_req_bufsize(fp) : VSTREAM_BUFSIZE)
+
 #ifdef VSTREAM_CTL_BUFSIZE
-    if (mss > VSTREAM_BUFSIZE) {
+    if (mss > EFF_BUFFER_SIZE(fp) / 2) {
        if (mss < INT_MAX / 2)
            mss *= 2;
        vstream_control(fp,