ivshmem-server: Don't overload POSIX shmem and file name

Option -m NAME is interpreted as directory name if we can statfs() it
and its on hugetlbfs.  Else it's interpreted as POSIX shared memory
object name.  This is nuts.

Always interpret -m as directory.  Create new -M for POSIX shared
memory.  Last of -m or -M wins.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <1458066895-20632-4-git-send-email-armbru@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>

1 files changed, 10 insertions, 46 deletions

diff --git a/contrib/ivshmem-server/ivshmem-server.c b/contrib/ivshmem-server/ivshmem-server.c
index bfd0fad..172db78 100644
--- a/contrib/ivshmem-server/ivshmem-server.c
+++ b/contrib/ivshmem-server/ivshmem-server.c
@@ -12,9 +12,6 @@
 #include <sys/mman.h>
 #include <sys/socket.h>
 #include <sys/un.h>
-#ifdef CONFIG_LINUX
-#include <sys/vfs.h>
-#endif
 
 #include "ivshmem-server.h"
 
@@ -257,7 +254,8 @@ ivshmem_server_ftruncate(int fd, unsigned shmsize)
 /* Init a new ivshmem server */
 int
 ivshmem_server_init(IvshmemServer *server, const char *unix_sock_path,
-                    const char *shm_path, size_t shm_size, unsigned n_vectors,
+                    const char *shm_path, bool use_shm_open,
+                    size_t shm_size, unsigned n_vectors,
                     bool verbose)
 {
     int ret;
@@ -278,6 +276,7 @@ ivshmem_server_init(IvshmemServer *server, const char *unix_sock_path,
         return -1;
     }
 
+    server->use_shm_open = use_shm_open;
     server->shm_size = shm_size;
     server->n_vectors = n_vectors;
 
@@ -286,31 +285,6 @@ ivshmem_server_init(IvshmemServer *server, const char *unix_sock_path,
     return 0;
 }
 
-#ifdef CONFIG_LINUX
-
-#define HUGETLBFS_MAGIC       0x958458f6
-
-static long gethugepagesize(const char *path)
-{
-    struct statfs fs;
-    int ret;
-
-    do {
-        ret = statfs(path, &fs);
-    } while (ret != 0 && errno == EINTR);
-
-    if (ret != 0) {
-        return -1;
-    }
-
-    if (fs.f_type != HUGETLBFS_MAGIC) {
-        return -1;
-    }
-
-    return fs.f_bsize;
-}
-#endif
-
 /* open shm, create and bind to the unix socket */
 int
 ivshmem_server_start(IvshmemServer *server)
@@ -319,27 +293,17 @@ ivshmem_server_start(IvshmemServer *server)
     int shm_fd, sock_fd, ret;
 
     /* open shm file */
-#ifdef CONFIG_LINUX
-    long hpagesize;
-
-    hpagesize = gethugepagesize(server->shm_path);
-    if (hpagesize < 0 && errno != ENOENT) {
-        IVSHMEM_SERVER_DEBUG(server, "cannot stat shm file %s: %s\n",
-                             server->shm_path, strerror(errno));
-    }
-
-    if (hpagesize > 0) {
+    if (server->use_shm_open) {
+        IVSHMEM_SERVER_DEBUG(server, "Using POSIX shared memory: %s\n",
+                             server->shm_path);
+        shm_fd = shm_open(server->shm_path, O_CREAT | O_RDWR, S_IRWXU);
+    } else {
         gchar *filename = g_strdup_printf("%s/ivshmem.XXXXXX", server->shm_path);
-        IVSHMEM_SERVER_DEBUG(server, "Using hugepages: %s\n", server->shm_path);
+        IVSHMEM_SERVER_DEBUG(server, "Using file-backed shared memory: %s\n",
+                             server->shm_path);
         shm_fd = mkstemp(filename);
         unlink(filename);
         g_free(filename);
-    } else
-#endif
-    {
-        IVSHMEM_SERVER_DEBUG(server, "Using POSIX shared memory: %s\n",
-                             server->shm_path);
-        shm_fd = shm_open(server->shm_path, O_CREAT|O_RDWR, S_IRWXU);
     }
 
     if (shm_fd < 0) {