libnvme: commit pre-generated accessor files and simplify build

The accessor functions (getters/setters for nvme_path, nvme_ns,
nvme_ctrl, nvme_subsystem, nvme_host, nvme_fabric_options) were
previously generated at build time by a custom_target in Meson.
They are now committed to the source tree and treated as
maintainer-generated source files, similar to how the Linux kernel
and systemd handle infrequently-changing generated code.

Changes:
 - Commit accessors.h, accessors.c, accessors.ld to the source tree
 - Remove the custom_target that ran the generator on every build;
   generate-accessors is no longer compiled during a normal build
 - Add accessors.c to the sources list and accessors.h to
   install_headers() alongside their sibling files in
   libnvme/src/meson.build
 - Remove accessors_dep (was only needed to forward the custom_target
   outputs; plain files don't require this indirection)
 - Enhance generate-accessors.c to emit mechanical Doxygen stubs in
   accessors.h, covering all three member kinds: value types, dynamic
   char * (with NULL/copy semantics), and fixed char arrays
 - Add update-accessors.sh: atomically regenerates accessors.h and
   accessors.c when content changes, and reports symbol additions and
   removals against accessors.ld without overwriting it
 - Add a Meson run_target and Makefile target 'update-accessors' for
   on-demand regeneration: make update-accessors
 - Keep accessors.ld manually maintained; its version section labels
   (e.g. LIBNVME_ACCESSORS_3_0) must be assigned by the maintainer to
   preserve ABI compatibility
 - Add .github/workflows/check-accessors.yml to fail CI when the
   committed accessor files drift from the generator output
 - Update README.md with a developer guide covering regeneration,
   accessors.ld maintenance, and the ABI versioning convention
 - Fix three stale test reference files that were missing dhchap_ctrl_key
   from their expected JSON output following an earlier json.c update

Signed-off-by: Martin Belanger <[email protected]>

Author: Martin Belanger

.github/workflows/check-accessors.yml

@@ -0,0 +1,48 @@
+---
+# SPDX-License-Identifier: GPL-2.0-or-later
+#
+# This file is part of nvme.
+# Copyright (c) 2025 Dell Technologies Inc. or its subsidiaries.
+#
+# Authors: Martin Belanger <[email protected]>
+#
+# Verify that the committed accessor files (accessors.h, accessors.c) are
+# up to date with the generate-accessors tool and the structs in private.h.
+#
+# If this check fails, run the following command and commit the result:
+#
+#   meson compile -C <build-dir> update-accessors
+
+name: Check accessors
+
+on:
+  push:
+    branches: [master]
+  pull_request:
+    branches: [master]
+
+  workflow_dispatch:
+
+jobs:
+  check-accessors:
+    name: check generated accessor files are up to date
+    runs-on: ubuntu-latest
+    container:
+      image: ghcr.io/linux-nvme/debian:latest
+    steps:
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
+      - name: Mark repo as safe for git
+        run: git config --global --add safe.directory "$GITHUB_WORKSPACE"
+      - name: Configure
+        run: meson setup .build-ci
+      - name: Regenerate accessor files
+        run: meson compile -C .build-ci update-accessors
+      - name: Check for uncommitted differences
+        run: |
+          if ! git diff --exit-code libnvme/src/nvme/accessors.h \
+                                    libnvme/src/nvme/accessors.c; then
+            echo ""
+            echo "ERROR: accessor files are out of date."
+            echo "Run 'meson compile -C <build-dir> update-accessors' and commit the result."
+            exit 1
+          fi

Makefile

@@ -45,6 +45,10 @@ install: ${NAME}
 uninstall:
 	cd ${BUILD-DIR} && meson --internal uninstall
 
+.PHONY: update-accessors
+update-accessors: ${BUILD-DIR}
+	meson compile -C ${BUILD-DIR} update-accessors
+
 .PHONY: dist
 dist: ${NAME}
 	meson dist -C ${BUILD-DIR} --formats gztar

README.md

@@ -61,7 +61,7 @@ Note for nvme-cli the 'default' is set to nofallback.
 #### Installing
 
 	# meson install -C .build
-	
+
 ### Build with build.sh wrapper
 
 The `scripts/build.sh` is used for the CI build but can also be used for
@@ -237,6 +237,93 @@ After that, you just need to implement the functions you defined in each
 ENTRY, then append the object file name to the meson.build "sources".
 
 
+### Updating the libnvme accessor functions
+
+libnvme exposes a set of getter and setter functions (accessors) for its core
+internal structs (`nvme_path`, `nvme_ns`, `nvme_ctrl`, `nvme_subsystem`,
+`nvme_host`, `nvme_fabric_options`). These are generated from the struct
+definitions in `libnvme/src/nvme/private.h` by the tool
+`libnvme/src/nvme/generate-accessors.c`.
+
+The generated files are committed to the source tree and are **not**
+regenerated during a normal build:
+
+```
+libnvme/src/nvme/accessors.h   # public API declarations (with Doxygen stubs)
+libnvme/src/nvme/accessors.c   # implementations
+libnvme/src/nvme/accessors.ld  # linker version script (manually maintained)
+```
+
+#### When to regenerate
+
+Regeneration is needed when a struct member is added, removed, or renamed in
+`private.h`, or when a struct is added to or removed from
+`generate-accessors-include.list` or excluded in `generate-accessors-exclude.list`.
+
+#### How to regenerate
+
+```shell
+$ make update-accessors
+```
+
+or equivalently:
+
+```shell
+$ meson compile -C .build update-accessors
+```
+
+The script compiles the generator, runs it, and atomically updates
+`accessors.h` and `accessors.c` only when their content changes.
+Commit the updated files afterward:
+
+```shell
+$ git add libnvme/src/nvme/accessors.h libnvme/src/nvme/accessors.c
+$ git commit -m "libnvme: regenerate accessors following <struct> changes"
+```
+
+#### Maintaining accessors.ld
+
+`accessors.ld` is a GNU linker version script that controls which accessor
+symbols are exported from `libnvme.so` and under which ABI version label they
+were introduced (e.g. `LIBNVME_ACCESSORS_3_0`).
+
+This file is **not** updated automatically, because each symbol must be placed
+in the correct version section by the maintainer. Adding a symbol to an
+already-published version section would break binary compatibility for
+existing users of the library.
+
+When `make update-accessors` detects that the symbol list has drifted from
+`accessors.ld`, it prints a report like the following:
+
+```
+WARNING: accessors.ld needs manual attention.
+
+  Symbols to ADD (place in a new version section, e.g. LIBNVME_ACCESSORS_X_Y):
+    nvme_ctrl_get_new_field
+    nvme_ctrl_set_new_field
+```
+
+New symbols must be added to a **new** version section that chains the
+previous one. For example, if the current latest section is
+`LIBNVME_ACCESSORS_3_0`, add a new section for the next release:
+
+```
+LIBNVME_ACCESSORS_3_1 {
+    global:
+        nvme_ctrl_get_new_field;
+        nvme_ctrl_set_new_field;
+} LIBNVME_ACCESSORS_3_0;
+```
+
+Then commit `accessors.ld` together with the regenerated source files.
+
+#### CI enforcement
+
+A GitHub Actions workflow (`.github/workflows/check-accessors.yml`) runs on
+every push and pull request. It regenerates the accessor files and fails if
+the result differs from what is committed, ensuring the source tree never
+drifts silently.
+
 ## Dependency
 
 libnvme depends on the /sys/class/nvme-subsystem interface which was

libnvme/src/libnvme.h

@@ -25,6 +25,7 @@ extern "C" {
 #include <nvme/tree.h>
 #include <nvme/types.h>
 #include <nvme/util.h>
+#include <nvme/accessors.h>
 
 #ifdef __cplusplus
 }

libnvme/src/meson.build

@@ -6,6 +6,7 @@
 # Authors: Martin Belanger <[email protected]>
 #
 sources = [
+    'nvme/accessors.c',
     'nvme/base64.c',
     'nvme/cmds.c',
     'nvme/crc32.c',
@@ -29,8 +30,7 @@ else
     sources += 'nvme/no-json.c'
 endif
 
-# Generate accessors (setter/getter functions)
-subdir('nvme')  # declares: accessors_dep, accessors_ld_full_path
+subdir('nvme')  # declares: accessors_ld_full_path
 
 deps = [
     config_dep,
@@ -40,7 +40,6 @@ deps = [
     libdbus_dep,
     liburing_dep,
     openssl_dep,
-    accessors_dep,
 ]
 
 ldfile = 'libnvme.ld'
@@ -98,6 +97,7 @@ install_headers(
 )
 install_headers(
     [
+        'nvme/accessors.h',
         'nvme/cmds.h',
         'nvme/fabrics.h',
         'nvme/filters.h',