Merging upstream version 256.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 82 insertions, 0 deletions

diff --git a/src/basic/dlfcn-util.h b/src/basic/dlfcn-util.h
new file mode 100644
index 0000000..83ab320
--- /dev/null
+++ b/src/basic/dlfcn-util.h
@@ -0,0 +1,82 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+#pragma once
+
+#include <dlfcn.h>
+
+#include "macro.h"
+
+static inline void* safe_dlclose(void *dl) {
+        if (!dl)
+                return NULL;
+
+        assert_se(dlclose(dl) == 0);
+        return NULL;
+}
+
+static inline void dlclosep(void **dlp) {
+        safe_dlclose(*dlp);
+}
+
+int dlsym_many_or_warn_sentinel(void *dl, int log_level, ...) _sentinel_;
+int dlopen_many_sym_or_warn_sentinel(void **dlp, const char *filename, int log_level, ...) _sentinel_;
+
+#define dlsym_many_or_warn(dl, log_level, ...) \
+        dlsym_many_or_warn_sentinel(dl, log_level, __VA_ARGS__, NULL)
+#define dlopen_many_sym_or_warn(dlp, filename, log_level, ...) \
+        dlopen_many_sym_or_warn_sentinel(dlp, filename, log_level, __VA_ARGS__, NULL)
+
+#define DLSYM_PROTOTYPE(symbol)                 \
+        extern typeof(symbol)* sym_##symbol
+#define DLSYM_FUNCTION(symbol)                  \
+        typeof(symbol)* sym_##symbol = NULL
+
+/* Macro useful for putting together variable/symbol name pairs when calling dlsym_many_or_warn(). Assumes
+ * that each library symbol to resolve will be placed in a variable with the "sym_" prefix, i.e. a symbol
+ * "foobar" is loaded into a variable "sym_foobar". */
+#define DLSYM_ARG(arg) \
+        ({ assert_cc(__builtin_types_compatible_p(typeof(sym_##arg), typeof(&arg))); &sym_##arg; }), STRINGIFY(arg)
+
+/* libbpf is a bit confused about type-safety and API compatibility. Provide a macro that can tape over that mess. Sad. */
+#define DLSYM_ARG_FORCE(arg) \
+        &sym_##arg, STRINGIFY(arg)
+
+#define ELF_NOTE_DLOPEN_VENDOR "FDO"
+#define ELF_NOTE_DLOPEN_TYPE UINT32_C(0x407c0c0a)
+#define ELF_NOTE_DLOPEN_PRIORITY_REQUIRED "required"
+#define ELF_NOTE_DLOPEN_PRIORITY_RECOMMENDED "recommended"
+#define ELF_NOTE_DLOPEN_PRIORITY_SUGGESTED "suggested"
+
+/* Add an ".note.dlopen" ELF note to our binary that declares our weak dlopen() dependency. This
+ * information can be read from an ELF file via "readelf -p .note.dlopen" or an equivalent command. */
+#define _ELF_NOTE_DLOPEN(json, variable_name)                              \
+        __attribute__((used, section(".note.dlopen"))) _Alignas(sizeof(uint32_t)) static const struct { \
+                struct {                                                   \
+                        uint32_t n_namesz, n_descsz, n_type;               \
+                } nhdr;                                                    \
+                char name[sizeof(ELF_NOTE_DLOPEN_VENDOR)];                 \
+                _Alignas(sizeof(uint32_t)) char dlopen_json[sizeof(json)]; \
+        } variable_name = {                                                \
+                .nhdr = {                                                  \
+                        .n_namesz = sizeof(ELF_NOTE_DLOPEN_VENDOR),        \
+                        .n_descsz = sizeof(json),                          \
+                        .n_type   = ELF_NOTE_DLOPEN_TYPE,                  \
+                },                                                         \
+                .name = ELF_NOTE_DLOPEN_VENDOR,                            \
+                .dlopen_json = json,                                       \
+        }
+
+#define _SONAME_ARRAY1(a) "[\""a"\"]"
+#define _SONAME_ARRAY2(a, b) "[\""a"\",\""b"\"]"
+#define _SONAME_ARRAY3(a, b, c) "[\""a"\",\""b"\",\""c"\"]"
+#define _SONAME_ARRAY4(a, b, c, d) "[\""a"\",\""b"\",\""c"\"",\""d"\"]"
+#define _SONAME_ARRAY5(a, b, c, d, e) "[\""a"\",\""b"\",\""c"\"",\""d"\",\""e"\"]"
+#define _SONAME_ARRAY_GET(_1,_2,_3,_4,_5,NAME,...) NAME
+#define _SONAME_ARRAY(...) _SONAME_ARRAY_GET(__VA_ARGS__, _SONAME_ARRAY5, _SONAME_ARRAY4, _SONAME_ARRAY3, _SONAME_ARRAY2, _SONAME_ARRAY1)(__VA_ARGS__)
+
+/* The 'priority' must be one of 'required', 'recommended' or 'suggested' as per specification, use the
+ * macro defined above to specify it.
+ * Multiple sonames can be passed and they will be automatically constructed into a json array (but note that
+ * due to preprocessor language limitations if more than the limit defined above is used, a new
+ * _SONAME_ARRAY<X+1> will need to be added). */
+#define ELF_NOTE_DLOPEN(feature, description, priority, ...) \
+        _ELF_NOTE_DLOPEN("[{\"feature\":\"" feature "\",\"description\":\"" description "\",\"priority\":\"" priority "\",\"soname\":" _SONAME_ARRAY(__VA_ARGS__) "}]", UNIQ_T(s, UNIQ))