From 6319ac5225aec738f134f338f68109822581bff1 Mon Sep 17 00:00:00 2001
From: Laurent Bercot <ska-skaware@skarnet.org>
Date: Sat, 6 Dec 2014 17:51:14 +0000
Subject: Rewrite unixmessage_receiver without buffer, only cbuffer

---
 src/libunixonacid/unixmessage_receive.c | 106 ++++++++++++++++++++++++++------
 1 file changed, 87 insertions(+), 19 deletions(-)

(limited to 'src/libunixonacid/unixmessage_receive.c')

diff --git a/src/libunixonacid/unixmessage_receive.c b/src/libunixonacid/unixmessage_receive.c
index dc75263..fed1b03 100644
--- a/src/libunixonacid/unixmessage_receive.c
+++ b/src/libunixonacid/unixmessage_receive.c
@@ -1,44 +1,112 @@
 /* ISC license. */
 
+#define _XPG4_2
+#include <skalibs/sysdeps.h>
+#include <skalibs/nonposix.h>
 #include <errno.h>
-#include <skalibs/allreadwrite.h>
-#include <skalibs/buffer.h>
+#include <sys/socket.h>
+#include <sys/uio.h>
+#include <skalibs/uint.h>
+#include <skalibs/diuint.h>
 #include <skalibs/cbuffer.h>
+#include <skalibs/djbunix.h>
 #include <skalibs/error.h>
+#include <skalibs/allreadwrite.h>
 #include <skalibs/stralloc.h>
-#include <skalibs/uint.h>
+#include <skalibs/siovec.h>
 #include <skalibs/unixmessage.h>
 
+static int unixmessage_receiver_fill (unixmessage_receiver_t *b, diuint *d)
+{
+  char ancilbuf[CMSG_SPACE(b->auxb.a - 1)] ;
+  struct iovec iov[2] ;
+  struct msghdr msghdr =
+  {
+    .msg_name = 0,
+    .msg_namelen = 0,
+    .msg_iov = iov,
+    .msg_iovlen = 2,
+    .msg_flags = 0,
+    .msg_control = ancilbuf,
+    .msg_controllen = sizeof(ancilbuf)
+  } ;
+  unsigned int auxlen ;
+  int r ;
+  if (cbuffer_isfull(&b->mainb) || cbuffer_isfull(&b->auxb))
+    return (errno = ENOBUFS, -1) ;
+  {
+    siovec_t v[2] ;
+    cbuffer_wpeek(&b->mainb, v) ;
+    iovec_from_siovec(iov, v, 2) ;
+  }
+#ifdef SKALIBS_HASCMSGCLOEXEC
+  r = recvmsg(b->fd, &msghdr, MSG_WAITALL | MSG_CMSG_CLOEXEC) ;
+#else
+  r = recvmsg(b->fd, &msghdr, MSG_WAITALL) ;
+#endif
+  if (r <= 0) return r ;
+  {
+    struct cmsghdr *c = CMSG_FIRSTHDR(&msghdr) ;
+    if (c)
+    {
+      if (c->cmsg_level != SOL_SOCKET
+       || c->cmsg_type != SCM_RIGHTS) return (errno = EPROTO, -1) ;
+      auxlen = (unsigned int)(c->cmsg_len - (CMSG_DATA(c) - (unsigned char *)c)) ;
+#ifndef SKALIBS_HASCMSGCLOEXEC
+      {
+        register unsigned int i = 0 ;
+        for (; i < auxlen/sizeof(int) ; i++)
+          if (coe(((int *)CMSG_DATA(c))[i]) < 0) return -1 ;
+      }
+#endif
+      if (msghdr.msg_flags & MSG_CTRUNC) return (errno = EPROTO, -1) ;
+      if (cbuffer_put(&b->auxb, (char *)CMSG_DATA(c), auxlen) < auxlen)
+        return (errno = ENOBUFS, -1) ;
+      d->right = auxlen / sizeof(int) ;
+      r -= c->cmsg_len ;
+    }
+  }
+  d->left = cbuffer_WSEEK(&b->mainb, r) ;
+  return 1 ;
+}
+
 int unixmessage_receive (unixmessage_receiver_t *b, unixmessage_t *m)
 {
-  if (b->data.len == b->mainlen)
+  if (b->maindata.len == b->mainlen && b->auxdata.len == b->auxlen)
   {
     char pack[sizeof(unsigned int) << 1] ;
-    if (buffer_len(&b->mainb) < sizeof(unsigned int) << 1)
+    if (cbuffer_len(&b->mainb) < sizeof(unsigned int) << 1)
     {
-      register int r = sanitize_read(buffer_fill(&b->mainb)) ;
+      diuint d ;
+      register int r = sanitize_read(unixmessage_receiver_fill(b, &d)) ;
       if (r <= 0) return r ;
-      if (r < sizeof(unsigned int) << 1) return (errno = EWOULDBLOCK, 0) ;
+      if (cbuffer_len(&b->mainb) < sizeof(unsigned int) << 1)
+        return (errno = EWOULDBLOCK, 0) ;
     }
-    buffer_getnofill(&b->mainb, pack, sizeof(unsigned int) << 1) ;
+    cbuffer_get(&b->mainb, pack, sizeof(unsigned int) << 1) ;
     uint_unpack_big(pack, &b->mainlen) ;
     uint_unpack_big(pack + sizeof(unsigned int), &b->auxlen) ;
-    if (b->auxlen > UNIXMESSAGE_MAXFDS) return (errno = EPROTO, -1) ;
     b->auxlen *= sizeof(int) ;
-    if (!stralloc_ready(&b->data, b->mainlen)) return -1 ;
-    b->data.len = 0 ;
-    b->auxw = cbuffer_get(&b->auxb, (char *)b->fds, b->auxlen) ;
+    if (!stralloc_ready(&b->maindata, b->mainlen)) return -1 ;
+    b->maindata.len = 0 ;
+    if (!stralloc_ready(&b->auxdata, b->auxlen)) return -1 ;
+    b->auxdata.len = 0 ;
   }
+
+  for (;;)
   {
-    register int r = buffer_getall(&b->mainb, b->data.s, b->mainlen, &b->data.len) ;
+    diuint d ;
+    register int r ;
+    b->maindata.len += cbuffer_get(&b->mainb, b->maindata.s + b->maindata.len, cbuffer_len(&b->mainb)) ;
+    b->auxdata.len += cbuffer_get(&b->auxb, b->auxdata.s + b->auxdata.len, cbuffer_len(&b->auxb)) ;
+    if (b->maindata.len == b->mainlen && b->auxdata.len == b->auxlen) break ;
+    r = sanitize_read(unixmessage_receiver_fill(b, &d)) ;
     if (r <= 0) return r ;
   }
-  if (b->auxw < b->auxlen)
-    b->auxw += cbuffer_get(&b->auxb, (char *)b->fds, b->auxlen - b->auxw) ;
-  if (b->auxw < b->auxlen) return (errno = EPROTO, -1) ;
-  m->s = b->data.s ;
-  m->len = b->data.len ;
-  m->fds = b->fds ;
+
+  m->s = b->maindata.s ;
+  m->len = b->maindata.len ;
+  m->fds = (int *)b->auxdata.s ;
   m->nfds = b->auxlen / sizeof(int) ;
   return 1 ;
 }
-- 
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