[PATCH 3/7] Xext: Enable MIT-SHM FD-passing request definitions only when possible

[Keith Packard]

Check to see if xtrans FD passing is available and use that to
advertise the appropriate version of the SHM extension

Signed-off-by: Keith Packard <keithp at keithp.com>
---
 Xext/shm.c                  | 14 +++++++++++++-
 Xext/shmint.h               | 17 ++++++++++++++++-
 include/protocol-versions.h |  4 ++++
 3 files changed, 33 insertions(+), 2 deletions(-)

diff --git a/Xext/shm.c b/Xext/shm.c
index 1a70260..109a381 100644
--- a/Xext/shm.c
+++ b/Xext/shm.c
@@ -384,7 +384,7 @@ ProcShmAttach(ClientPtr client)
         return BadValue;
     }
     for (shmdesc = Shmsegs; shmdesc; shmdesc = shmdesc->next) {
-        if (!shmdesc->is_fd && shmdesc->shmid == stuff->shmid)
+        if (!SHMDESC_IS_FD(shmdesc) && shmdesc->shmid == stuff->shmid)
             break;
     }
     if (shmdesc) {
@@ -396,7 +396,9 @@ ProcShmAttach(ClientPtr client)
         shmdesc = malloc(sizeof(ShmDescRec));
         if (!shmdesc)
             return BadAlloc;
+#ifdef SHM_FD_PASSING
         shmdesc->is_fd = FALSE;
+#endif
         shmdesc->addr = shmat(stuff->shmid, 0,
                               stuff->readOnly ? SHM_RDONLY : 0);
         if ((shmdesc->addr == ((char *) -1)) || SHMSTAT(stuff->shmid, &buf)) {
@@ -435,9 +437,11 @@ ShmDetachSegment(pointer value, /* must conform to DeleteType */
 
     if (--shmdesc->refcnt)
         return TRUE;
+#if SHM_FD_PASSING
     if (shmdesc->is_fd)
         munmap(shmdesc->addr, shmdesc->size);
     else
+#endif
         shmdt(shmdesc->addr);
     for (prev = &Shmsegs; *prev != shmdesc; prev = &(*prev)->next);
     *prev = shmdesc->next;
@@ -1094,6 +1098,7 @@ ProcShmCreatePixmap(ClientPtr client)
     return BadAlloc;
 }
 
+#ifdef SHM_FD_PASSING
 static int
 ProcShmAttachFd(ClientPtr client)
 {
@@ -1209,6 +1214,7 @@ ProcShmCreateSegment(ClientPtr client)
     WriteToClient(client, sizeof (xShmCreateSegmentReply), &rep);
     return Success;
 }
+#endif /* SHM_FD_PASSING */
 
 static int
 ProcShmDispatch(ClientPtr client)
@@ -1239,10 +1245,12 @@ ProcShmDispatch(ClientPtr client)
             return ProcPanoramiXShmCreatePixmap(client);
 #endif
         return ProcShmCreatePixmap(client);
+#ifdef SHM_FD_PASSING
     case X_ShmAttachFd:
         return ProcShmAttachFd(client);
     case X_ShmCreateSegment:
         return ProcShmCreateSegment(client);
+#endif
     default:
         return BadRequest;
     }
@@ -1343,6 +1351,7 @@ SProcShmCreatePixmap(ClientPtr client)
     return ProcShmCreatePixmap(client);
 }
 
+#ifdef SHM_FD_PASSING
 static int
 SProcShmAttachFd(ClientPtr client)
 {
@@ -1364,6 +1373,7 @@ SProcShmCreateSegment(ClientPtr client)
     swapl(&stuff->size);
     return ProcShmCreateSegment(client);
 }
+#endif  /* SHM_FD_PASSING */
 
 static int
 SProcShmDispatch(ClientPtr client)
@@ -1382,10 +1392,12 @@ SProcShmDispatch(ClientPtr client)
         return SProcShmGetImage(client);
     case X_ShmCreatePixmap:
         return SProcShmCreatePixmap(client);
+#ifdef SHM_FD_PASSING
     case X_ShmAttachFd:
         return SProcShmAttachFd(client);
     case X_ShmCreateSegment:
         return SProcShmCreateSegment(client);
+#endif
     default:
         return BadRequest;
     }
diff --git a/Xext/shmint.h b/Xext/shmint.h
index db35fbb..7b3ea9b 100644
--- a/Xext/shmint.h
+++ b/Xext/shmint.h
@@ -56,16 +56,31 @@ typedef struct _ShmFuncs {
     void (*PutImage) (XSHM_PUT_IMAGE_ARGS);
 } ShmFuncs, *ShmFuncsPtr;
 
+#include <protocol-versions.h>
+
+#if SERVER_SHM_MAJOR_VERSION == 1 && SERVER_SHM_MINOR_VERSION >= 2
+#define SHM_FD_PASSING  1
+#endif
+
 typedef struct _ShmDesc {
     struct _ShmDesc *next;
     int shmid;
     int refcnt;
     char *addr;
-    Bool is_fd;
     Bool writable;
     unsigned long size;
+#ifdef SHM_FD_PASSING
+    Bool is_fd;
+    XID resource;
+#endif
 } ShmDescRec, *ShmDescPtr;
 
+#ifdef SHM_FD_PASSING
+#define SHMDESC_IS_FD(shmdesc)  ((shmdesc)->is_fd)
+#else
+#define SHMDESC_IS_FD(shmdesc)  (0)
+#endif
+
 extern _X_EXPORT void
  ShmRegisterFuncs(ScreenPtr pScreen, ShmFuncsPtr funcs);
 
diff --git a/include/protocol-versions.h b/include/protocol-versions.h
index 5ceaeb0..95df8ce 100644
--- a/include/protocol-versions.h
+++ b/include/protocol-versions.h
@@ -93,7 +93,11 @@
 
 /* SHM */
 #define SERVER_SHM_MAJOR_VERSION		1
+#if XTRANS_SEND_FDS
+#define SERVER_SHM_MINOR_VERSION		2
+#else
 #define SERVER_SHM_MINOR_VERSION		1
+#endif
 
 /* Sync */
 #define SERVER_SYNC_MAJOR_VERSION		3
-- 
1.8.4.2