Add new public facing API nvc_nvcaps_style()

It returns what type of nvidia-capabilities are supported. Choices are
{none, proc-based, dev-based}.

Signed-off-by: Kevin Klues <[email protected]>

Author: klueska

pkg/deb/libnvidia-container@[email protected]

@@ -10,6 +10,7 @@ libnvidia-container.so.1 libnvidia-container1 #MINVER#
  nvc_context_new@NVC_1.0 1.2.0~rc.3
  nvc_device_info_free@NVC_1.0 1.2.0~rc.3
  nvc_device_info_new@NVC_1.0 1.2.0~rc.3
+ nvc_nvcaps_style@NVC_1.0 1.2.0~rc.3
  nvc_nvcaps_device_from_proc_path@NVC_1.0 1.2.0~rc.3
  nvc_device_mount@NVC_1.0 1.2.0~rc.3
  nvc_mig_device_access_caps_mount@NVC_1.0 1.2.0~rc.3

src/libnvidia-container.lds

@@ -33,6 +33,7 @@ VERSION {
             nvc_device_info_free;
             nvc_driver_mount;
             nvc_device_mount;
+            nvc_nvcaps_style;
             nvc_nvcaps_device_from_proc_path;
             nvc_mig_device_access_caps_mount;
             nvc_mig_config_global_caps_mount;

src/nvc.h

@@ -20,6 +20,10 @@ extern "C" {
 
 #define NVC_ARG_MAX 256
 
+#define NVC_NVCAPS_STYLE_NONE 0
+#define NVC_NVCAPS_STYLE_PROC 1
+#define NVC_NVCAPS_STYLE_DEV  2
+
 struct nvc_context;
 struct nvc_container;
 
@@ -121,6 +125,8 @@ void nvc_driver_info_free(struct nvc_driver_info *);
 struct nvc_device_info *nvc_device_info_new(struct nvc_context *, const char *);
 void nvc_device_info_free(struct nvc_device_info *);
 
+int nvc_nvcaps_style(void);
+
 int nvc_nvcaps_device_from_proc_path(struct nvc_context *, const char *, struct nvc_device_node *);
 
 int nvc_driver_mount(struct nvc_context *, const struct nvc_container *, const struct nvc_driver_info *);

src/nvc_info.c

@@ -790,6 +790,16 @@ nvc_device_info_free(struct nvc_device_info *info)
         free(info);
 }
 
+int
+nvc_nvcaps_style(void)
+{
+        if (nvidia_get_chardev_major(NV_CAPS_MODULE_NAME) >= 0)
+                return NVC_NVCAPS_STYLE_DEV;
+        if (file_exists(NULL, NV_PROC_DRIVER_CAPS) >= 0)
+                return NVC_NVCAPS_STYLE_PROC;
+        return NVC_NVCAPS_STYLE_NONE;
+}
+
 int
 nvc_nvcaps_device_from_proc_path(struct nvc_context *ctx, const char *cap_path, struct nvc_device_node *node)
 {