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/* 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))
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