Changeset e8e9052

Timestamp:

05/18/18 14:54:59 (3 years ago)

Author:

Shane Alcock <salcock@…>

Branches:

cachetimestamps, develop, master, rc-4.0.4, ringdecrementfix, ringperformance

Children:

5577521

Parents:

a7e4f40

Message:

Fix build error on older kernels that don't have memfd_create

We now fall back to shm_open() if memfd_create isn't available.

Files:

• configure.in (modified) (1 diff)
• lib/data-struct/simple_circular_buffer.c (modified) (3 diffs)

configure.in

@@ -554 +554 @@
 
 
+have_memfd_create=no
+AC_RUN_IFELSE([AC_LANG_PROGRAM([
+#include <sys/syscall.h>
+],[
+#ifndef __NR_memfd_create
+exit(1)
+#endif
+])], [have_memfd_create=yes])
+
+if test "$have_memfd_create" = "yes"; then
+        AC_DEFINE(HAVE_MEMFD_CREATE, 1, [Set to 1 if kernel supports memfd_create syscall])
+fi
+
 # Stupid AC_SEARCH_LIB appends stuff to LIBS even when I don't want it to, so
 # just set libs to null here to avoid linking against them by default

lib/data-struct/simple_circular_buffer.c

@@ -7 +7 @@
 #include <stdio.h>
 #include <sys/syscall.h>
+#include <sys/stat.h>
+#include <fcntl.h>
 #include <sys/socket.h>
 
@@ -21 +23 @@
 
         snprintf(anonname, 32, "lt_scb_%u", id);
+#ifdef HAVE_MEMFD_CREATE
         buf->fd = syscall(__NR_memfd_create, anonname, 0);
+#else
+        buf->fd = shm_open(anonname, O_RDWR | O_CREAT, 0600);
+#endif
         ftruncate(buf->fd, size);
 
@@ -36 +42 @@
 
 DLLEXPORT void libtrace_scb_destroy(libtrace_scb_t *buf) {
+        /* TODO shm_unlink the file name if we used shm_open? */
+
         munmap(buf->address, buf->count_bytes * 2);
+        close(buf->fd);
 }