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-rw-r--r--erts/doc/src/erl_driver.xml7
-rw-r--r--erts/doc/src/erl_nif.xml26
-rw-r--r--erts/emulator/beam/erl_bif_ddll.c6
-rw-r--r--erts/emulator/beam/erl_driver.h16
-rw-r--r--erts/emulator/beam/erl_nif.c6
-rw-r--r--erts/emulator/beam/erl_nif.h12
-rw-r--r--erts/emulator/test/driver_SUITE_data/smaller_major_vsn_drv.c4
7 files changed, 69 insertions, 8 deletions
diff --git a/erts/doc/src/erl_driver.xml b/erts/doc/src/erl_driver.xml
index 8da1836da7..ad37813ac0 100644
--- a/erts/doc/src/erl_driver.xml
+++ b/erts/doc/src/erl_driver.xml
@@ -315,10 +315,13 @@
<c>ERL_DRV_EXTENDED_MINOR_VERSION</c> will be incremented when
new features are added. The runtime system uses the minor version
of the driver to determine what features to use.
- The runtime system will refuse to load a driver if the major
+ The runtime system will normally refuse to load a driver if the major
versions differ, or if the major versions are equal and the
minor version used by the driver is greater than the one used
- by the runtime system.</p>
+ by the runtime system. Old drivers with lower major versions
+ will however be allowed after a bump of the major version during
+ a transition period of two major releases. Such old drivers might
+ however fail if deprecated features are used.</p>
<p>The emulator will refuse to load a driver that does not use
the extended driver interface,
to allow for 64-bit capable drivers,
diff --git a/erts/doc/src/erl_nif.xml b/erts/doc/src/erl_nif.xml
index 8b19725c02..6b1f4cccf8 100644
--- a/erts/doc/src/erl_nif.xml
+++ b/erts/doc/src/erl_nif.xml
@@ -316,6 +316,32 @@ ok
<p>The library initialization callbacks <c>load</c>, <c>reload</c> and
<c>upgrade</c> are all thread-safe even for shared state data.</p>
</item>
+
+ <tag><marker id="version_management"/>Version Management</tag>
+ <item><p>
+ When a NIF library is built, information about NIF API version
+ is compiled into the library. When a NIF library is loaded the
+ runtime system verifies that the library is of a compatible version.
+ <c>erl_nif.h</c> defines <c>ERL_NIF_MAJOR_VERSION</c>, and
+ <c>ERL_NIF_MINOR_VERSION</c>. <c>ERL_NIF_MAJOR_VERSION</c> will be
+ incremented when NIF library incompatible changes are made to the
+ Erlang runtime system. Normally it will suffice to recompile the NIF
+ library when the <c>ERL_NIF_MAJOR_VERSION</c> has changed, but it
+ could, under rare circumstances, mean that NIF libraries have to
+ be slightly modified. If so, this will of course be documented.
+ <c>ERL_NIF_MINOR_VERSION</c> will be incremented when
+ new features are added. The runtime system uses the minor version
+ to determine what features to use.
+ </p><p>
+ The runtime system will normally refuse to load a NIF library if
+ the major versions differ, or if the major versions are equal and
+ the minor version used by the NIF library is greater than the one
+ used by the runtime system. Old NIF libraries with lower major
+ versions will however be allowed after a bump of the major version
+ during a transition period of two major releases. Such old NIF
+ libraries might however fail if deprecated features are used.
+ </p></item>
+
<tag>Dirty NIFs</tag>
<item><p><marker id="dirty_nifs"/><em>Note that the dirty NIF functionality
is experimental</em> and that you have to enable support for dirty
diff --git a/erts/emulator/beam/erl_bif_ddll.c b/erts/emulator/beam/erl_bif_ddll.c
index 1728b200f7..56cd2ba04f 100644
--- a/erts/emulator/beam/erl_bif_ddll.c
+++ b/erts/emulator/beam/erl_bif_ddll.c
@@ -1548,8 +1548,10 @@ static int do_load_driver_entry(DE_Handle *dh, char *path, char *name)
switch (dp->extended_marker) {
case ERL_DRV_EXTENDED_MARKER:
- if (ERL_DRV_EXTENDED_MAJOR_VERSION != dp->major_version
- || ERL_DRV_EXTENDED_MINOR_VERSION < dp->minor_version) {
+ if (dp->major_version < ERL_DRV_MIN_REQUIRED_MAJOR_VERSION_ON_LOAD
+ || (ERL_DRV_EXTENDED_MAJOR_VERSION < dp->major_version
+ || (ERL_DRV_EXTENDED_MAJOR_VERSION == dp->major_version
+ && ERL_DRV_EXTENDED_MINOR_VERSION < dp->minor_version))) {
/* Incompatible driver version */
res = ERL_DE_LOAD_ERROR_INCORRECT_VERSION;
goto error;
diff --git a/erts/emulator/beam/erl_driver.h b/erts/emulator/beam/erl_driver.h
index 5517c26ba4..3ecb379326 100644
--- a/erts/emulator/beam/erl_driver.h
+++ b/erts/emulator/beam/erl_driver.h
@@ -136,6 +136,22 @@ typedef struct {
#define ERL_DRV_EXTENDED_MINOR_VERSION 0
/*
+ * The emulator will refuse to load a driver with a major version
+ * lower than ERL_DRV_MIN_REQUIRED_MAJOR_VERSION_ON_LOAD. The load
+ * may however fail if user have not removed use of deprecated
+ * symbols.
+ *
+ * The ERL_DRV_MIN_REQUIRED_MAJOR_VERSION_ON_LOAD have to allow
+ * loading of drivers built at least two major OTP releases
+ * ago.
+ *
+ * Bump of major version to 3 happened in OTP 17. That is, in
+ * OTP 19 we can increase ERL_DRV_MIN_REQUIRED_MAJOR_VERSION_ON_LOAD
+ * to 3.
+ */
+#define ERL_DRV_MIN_REQUIRED_MAJOR_VERSION_ON_LOAD 2
+
+/*
* The emulator will refuse to load a driver with different major
* version than the one used by the emulator.
*/
diff --git a/erts/emulator/beam/erl_nif.c b/erts/emulator/beam/erl_nif.c
index 40860e141c..063dba056e 100644
--- a/erts/emulator/beam/erl_nif.c
+++ b/erts/emulator/beam/erl_nif.c
@@ -2049,8 +2049,10 @@ BIF_RETTYPE load_nif_2(BIF_ALIST_2)
(entry = erts_sys_ddll_call_nif_init(init_func)) == NULL)) {
ret = load_nif_error(BIF_P, bad_lib, "Library init-call unsuccessful");
}
- else if (entry->major != ERL_NIF_MAJOR_VERSION
- || entry->minor > ERL_NIF_MINOR_VERSION
+ else if (entry->major < ERL_NIF_MIN_REQUIRED_MAJOR_VERSION_ON_LOAD
+ || (ERL_NIF_MAJOR_VERSION < entry->major
+ || (ERL_NIF_MAJOR_VERSION == entry->major
+ && ERL_NIF_MINOR_VERSION < entry->minor))
|| (entry->major==2 && entry->minor == 5)) { /* experimental maps */
ret = load_nif_error(BIF_P, bad_lib, "Library version (%d.%d) not compatible (with %d.%d).",
diff --git a/erts/emulator/beam/erl_nif.h b/erts/emulator/beam/erl_nif.h
index c12ba4d554..5b93c2398e 100644
--- a/erts/emulator/beam/erl_nif.h
+++ b/erts/emulator/beam/erl_nif.h
@@ -46,6 +46,18 @@
#define ERL_NIF_MAJOR_VERSION 2
#define ERL_NIF_MINOR_VERSION 6
+/*
+ * The emulator will refuse to load a nif-lib with a major version
+ * lower than ERL_NIF_MIN_REQUIRED_MAJOR_VERSION_ON_LOAD. The load
+ * may however fail if user have not removed use of deprecated
+ * symbols.
+ *
+ * The ERL_NIF_MIN_REQUIRED_MAJOR_VERSION_ON_LOAD have to allow
+ * loading of nif-libs built at least two major OTP releases
+ * ago.
+ */
+#define ERL_NIF_MIN_REQUIRED_MAJOR_VERSION_ON_LOAD 2
+
#include <stdlib.h>
#ifdef SIZEOF_CHAR
diff --git a/erts/emulator/test/driver_SUITE_data/smaller_major_vsn_drv.c b/erts/emulator/test/driver_SUITE_data/smaller_major_vsn_drv.c
index a1299fe807..6b9d4745ba 100644
--- a/erts/emulator/test/driver_SUITE_data/smaller_major_vsn_drv.c
+++ b/erts/emulator/test/driver_SUITE_data/smaller_major_vsn_drv.c
@@ -20,12 +20,12 @@
* Author: Rickard Green
*
* Description: Implementation of a driver with a smaller major
- * driver version than the current system.
+ * driver version than allowed on load.
*/
#define VSN_MISMATCH_DRV_NAME_STR "smaller_major_vsn_drv"
#define VSN_MISMATCH_DRV_NAME smaller_major_vsn_drv
-#define VSN_MISMATCH_DRV_MAJOR_VSN_DIFF (-1)
+#define VSN_MISMATCH_DRV_MAJOR_VSN_DIFF (ERL_DRV_MIN_REQUIRED_MAJOR_VERSION_ON_LOAD - ERL_DRV_EXTENDED_MAJOR_VERSION - 1)
#define VSN_MISMATCH_DRV_MINOR_VSN_DIFF 0
#include "vsn_mismatch_drv_impl.c"