xiaoxiang781216 commented on code in PR #20492:
URL: https://github.com/apache/nuttx/pull/20492#discussion_r4250864451
##########
libs/libc/elf/elf_registry.c:
##########
@@ -46,13 +47,35 @@
* Private Data
****************************************************************************/
+/* One lock for every registry. g_mod_registry holds the kernel modules of
+ * insmod(); what dlopen() loads is on the registry of the task group.
+ */
+
static rmutex_t g_modlock = NXRMUTEX_INITIALIZER;
static FAR struct module_s *g_mod_registry;
/****************************************************************************
* Public Functions
****************************************************************************/
+/****************************************************************************
+ * Name: libelf_registry
+ ****************************************************************************/
+
+FAR struct module_s **libelf_registry(void)
+{
+ return &task_get_info()->ta_modules;
+}
+
+/****************************************************************************
+ * Name: libelf_registry_kernel
+ ****************************************************************************/
+
+FAR struct module_s **libelf_registry_kernel(void)
Review Comment:
move to module
##########
include/nuttx/lib/elf.h:
##########
@@ -175,6 +175,10 @@ struct fdpic_desc_s;
struct module_s
{
FAR struct module_s *flink; /* Supports a singly linked list */
+ FAR struct module_s **registry; /* The registry this module is on */
+ FAR struct module_s *libraries; /* exec(): its own registry, for
Review Comment:
why need add libraries/registry field? we just need a link list and hold the
head in tls
##########
libs/libc/elf/elf_bind.c:
##########
@@ -1040,7 +984,8 @@ static int libelf_relocatedyn(FAR struct module_s *modp,
return ret;
}
- handle = libelf_insertneeded((FAR const char *)loadinfo->iobuffer);
+ handle = libelf_insertneeded(modp->registry,
Review Comment:
why not insert to ta_modules
##########
libs/libc/elf/elf_registry.c:
##########
@@ -46,13 +47,35 @@
* Private Data
****************************************************************************/
+/* One lock for every registry. g_mod_registry holds the kernel modules of
+ * insmod(); what dlopen() loads is on the registry of the task group.
+ */
+
static rmutex_t g_modlock = NXRMUTEX_INITIALIZER;
static FAR struct module_s *g_mod_registry;
/****************************************************************************
* Public Functions
****************************************************************************/
+/****************************************************************************
+ * Name: libelf_registry
+ ****************************************************************************/
+
+FAR struct module_s **libelf_registry(void)
Review Comment:
move to dlfnc
##########
libs/libc/elf/elf_remove.c:
##########
@@ -289,3 +290,42 @@ int libelf_remove(FAR void *handle)
set_errno(-ret);
return ERROR;
}
+
+/****************************************************************************
+ * Name: libelf_closeall
+ *
+ * Description:
+ * Give back every reference that dlopen() took in a registry. A module
+ * that another one still depends on goes with its last dependent.
+ *
+ ****************************************************************************/
+
+void libelf_closeall(FAR struct module_s **registry)
Review Comment:
libelf_removeall
##########
Documentation/os/binfmt/kernel_modules_vs_shared_libraries.rst:
##########
@@ -139,40 +139,52 @@ FLAT build.
Opening a Library More Than Once
================================
-In the FLAT and PROTECTED builds, ``dlopen()`` of a library that is already
+In the FLAT and PROTECTED builds, each task group has its own list of
+loaded libraries. ``dlopen()`` of a library that the task group already
loaded does not load a second copy and does not fail. It returns a handle to
the library that is already loaded and takes an additional reference on it.
Each successful ``dlopen()`` must be matched by a ``dlclose()``; the library
is unloaded only when the last handle is closed. Up to 255 handles may be
outstanding on one library; beyond that ``dlopen()`` fails with ``EMFILE``.
+The libraries that a task group did not close are closed when it exits.
+In the PROTECTED build only ``exit()`` closes them, so a task group that
+ends in another way leaves them loaded.
Some consequences worth keeping in mind:
* A library is identified by the *basename* of the path passed to
``dlopen()``. Two files with the same basename in different directories
are treated as the same library, and the second ``dlopen()`` will return
the first one.
-* There is only one instance of the library's ``.data`` and ``.bss``. Global
- and static data are shared by every user of the library, and by every task
- group in the system.
-* Constructors in ``.init_array`` run once, when the library is first loaded,
- and destructors in ``.fini_array`` run once, when the last handle is
- closed. They do not run per ``dlopen()``/``dlclose()`` pair.
+* Each task group that opens a library loads its own copy. Global and static
+ data are shared by the threads of one task group, not between task groups.
+ Only an FDPIC library executed in place from xipfs shares its ``.text``
+ between task groups.
+* Constructors in ``.init_array`` run once per task group, when the library
+ is first loaded in it, and destructors in ``.fini_array`` run once, when
+ its last handle in the task group is closed. They do not run per
+ ``dlopen()``/``dlclose()`` pair.
+* The libraries that a program loaded by ``exec()`` names in ``DT_NEEDED``
+ belong to its task group in the FLAT build, so ``dlopen()`` of one of them
Review Comment:
does DT_NEEDED work in protected/kernel build now?
##########
libs/libc/elf/elf_remove.c:
##########
@@ -289,3 +290,42 @@ int libelf_remove(FAR void *handle)
set_errno(-ret);
return ERROR;
}
+
+/****************************************************************************
+ * Name: libelf_closeall
+ *
+ * Description:
+ * Give back every reference that dlopen() took in a registry. A module
+ * that another one still depends on goes with its last dependent.
+ *
+ ****************************************************************************/
+
+void libelf_closeall(FAR struct module_s **registry)
+{
+ FAR struct module_s *modp;
+
+ libelf_registry_lock();
Review Comment:
should use per task lock from tls
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