X-Git-Url: https://git.distorted.org.uk/~mdw/fwd/blobdiff_plain/e82f7154f65062d9ac8b9677862774498b331058..bdbbfcd4eb2f6e15270f558342630d964cb9f418:/chan.c

diff --git a/chan.c b/chan.c
index 55e6a75..2e483cd 100644
--- a/chan.c
+++ b/chan.c
@@ -1,10 +1,10 @@
 /* -*-c-*-
  *
- * $Id: chan.c,v 1.1 1999/07/01 08:56:23 mdw Exp $
+ * $Id: chan.c,v 1.6 2003/10/31 13:56:14 mdw Exp $
  *
  * Channel management
  *
- * (c) 1999 Mark Wooding
+ * (c) 1999 Straylight/Edgeware
  */
 
 /*----- Licensing notice --------------------------------------------------* 
@@ -29,8 +29,25 @@
 /*----- Revision history --------------------------------------------------* 
  *
  * $Log: chan.c,v $
- * Revision 1.1  1999/07/01 08:56:23  mdw
- * Initial revision
+ * Revision 1.6  2003/10/31 13:56:14  mdw
+ * Fix data corruption in channel\!
+ *
+ * Revision 1.5  2000/07/19 17:55:43  mdw
+ * (writechan): Pointless tweak: when the buffer is empty, reset the start
+ * pointer to the beginning.  This saves doing slightly trickier
+ * @writev(2)@ calls when loading is light.
+ *
+ * Revision 1.4  1999/08/31 17:42:49  mdw
+ * Use `sel_force' to avoid a `select' call between reads and writes.
+ *
+ * Revision 1.3  1999/07/27 18:30:53  mdw
+ * Various minor portability fixes.
+ *
+ * Revision 1.2  1999/07/26 23:27:52  mdw
+ * Minor modifications for new design.
+ *
+ * Revision 1.1.1.1  1999/07/01 08:56:23  mdw
+ * Initial revision.
  *
  */
 
@@ -48,10 +65,6 @@
 #include <unistd.h>
 #include <sys/uio.h>
 
-#include <sys/socket.h>
-#include <netinet/in.h>
-#include <arpa/inet.h>
-
 #include <mLib/alloc.h>
 #include <mLib/conn.h>
 #include <mLib/sel.h>
@@ -59,6 +72,12 @@
 #include "chan.h"
 #include "fw.h"
 
+#ifdef CHAN_DEBUG
+#  define D(x) x
+#else
+#  define D(x)
+#endif
+
 /*----- Main code ---------------------------------------------------------*/
 
 /* --- @writechan@ --- *
@@ -85,16 +104,22 @@ static void writechan(int fd, unsigned mode, void *vp)
 
     /* --- Do the write --- */
 
-    if (base + len <= CHAN_BUFSZ)
+    D( printf("writechan %d: base = %u, len = %u; ", fd, base, len); )
+    if (base + len <= CHAN_BUFSZ) {
+      D( printf("%u:%u", base, len); )
       w = write(fd, c->buf + base, len);
-    else {
+    } else {
       struct iovec iov[2];
       iov[0].iov_base = c->buf + base;
       iov[0].iov_len = CHAN_BUFSZ - base;
       iov[1].iov_base = c->buf;
       iov[1].iov_len = len - iov[0].iov_len;
+      D( printf("%u:%u, %u:%u",
+		base, CHAN_BUFSZ - base,
+		0, len + base - CHAN_BUFSZ); )
       w = writev(fd, iov, 2);
     }
+    D( printf("; returned %d\n", w); )
 
     /* --- Sift through the results --- */
 
@@ -108,15 +133,17 @@ static void writechan(int fd, unsigned mode, void *vp)
     else if (c->len == CHAN_BUFSZ && !(c->f & CHANF_CLOSE))
       sel_addfile(&c->r);
     c->len -= w;
+    c->base += w;
   }
   if (c->len == 0)
     sel_rmfile(&c->w);
 
   /* --- Close the output end if necessary --- */
 
-  if (c->len == 0 && (c->f & CHANF_CLOSE)) {
-    shutdown(fd, 1);
-    c->func(c->p);
+  if (c->len == 0) {
+    c->base = 0;
+    if (c->f & CHANF_CLOSE)
+      c->func(c->p);
   }
   return;
 
@@ -142,21 +169,30 @@ static void readchan(int fd, unsigned mode, void *vp)
 {
   chan *c = vp;
   int r;
-  unsigned base = (c->base + c->len) & (CHAN_BUFSZ - 1);
-  unsigned len = CHAN_BUFSZ - c->len;
+  unsigned base = c->base;
+  unsigned len = c->len;
 
   /* --- Do the read --- */
 
-  if (base + len <= CHAN_BUFSZ)
-    r = read(fd, c->buf + base, len);
-  else {
+  D( printf("readchan %d: base = %u, len = %u; ", fd, base, len); )
+  if (base == 0) {
+    D( printf("%u:%u", len, CHAN_BUFSZ - len); )
+    r = read(fd, c->buf + len, CHAN_BUFSZ - len);
+  } else if (base + len >= CHAN_BUFSZ) {
+    D( printf("%u:%u", base + len - CHAN_BUFSZ, CHAN_BUFSZ - len); )
+    r = read(fd, c->buf + base + len - CHAN_BUFSZ, CHAN_BUFSZ - len);
+  } else {
     struct iovec iov[2];
-    iov[0].iov_base = c->buf + base;
-    iov[0].iov_len = CHAN_BUFSZ - base;
+    iov[0].iov_base = c->buf + base + len;
+    iov[0].iov_len = CHAN_BUFSZ - base - len;
     iov[1].iov_base = c->buf;
-    iov[1].iov_len = len - iov[0].iov_len;
+    iov[1].iov_len = base;
+    D( printf("%u:%u, %u:%u",
+	      base + len, CHAN_BUFSZ - base - len,
+	      0, base); )
     r = readv(fd, iov, 2);
   }
+  D( printf("; returned %d\n", r); )
 
   /* --- Sift through the results --- */
 
@@ -167,8 +203,10 @@ static void readchan(int fd, unsigned mode, void *vp)
   }
   else if (r == 0)
     goto close;
-  else if (c->len == 0 && !(c->f & CHANF_READY))
+  else if (c->len == 0 && (c->f & CHANF_READY)) {
     sel_addfile(&c->w);
+    sel_force(&c->w);
+  }
   c->len += r;
   if (c->len == CHAN_BUFSZ)
     sel_rmfile(&c->r);
@@ -178,8 +216,10 @@ static void readchan(int fd, unsigned mode, void *vp)
 
 close:
   c->f |= CHANF_CLOSE;
-  if (!c->len)
+  if (!c->len && (c->f & CHANF_READY)) {
     sel_addfile(&c->w);
+    sel_force(&c->w);
+  }
   sel_rmfile(&c->r);
 }
 
@@ -216,8 +256,11 @@ void chan_dest(chan *c, int fd)
   if (c->f & CHANF_READY)
     return;
   sel_initfile(sel, &c->w, fd, SEL_WRITE, writechan, c);
-  if (c->len)
+  if (c->len || (c->f & CHANF_CLOSE)) {
     sel_addfile(&c->w);
+    sel_force(&c->w);
+  }
+  c->f |= CHANF_READY;
 }
 
 /* --- @chan_open@ --- *