Various dlopen/linking cleanups from #42100 (#42166)

- **bpf-util: rename from bpf-dlopen, unify version-specific symbol
handling**
- **cryptsetup: dlopen libcryptsetup in tokens**
- **tree-wide: dlopen libpam in pam plugins**
- **test-bus-marshal: dlopen() glib and libdbus instead of linking
directly**
- **lock-util: Simplify timeout for lock_generic_with_timeout()**
- **color-util: simplify hsv_to_rgb, fix rgb_to_hsv negative-hue wrap**
- **tree-wide: Use our own macros instead of fabs()/fmax()/fmin()**
- **locale-util: dlopen() libintl instead of linking against it**
- **home: Use log2u64() over log2()**
- **meson: drop libdl, threads, and librt dependencies**
- **libc: Use dlsym() from a constructor instead of weak symbols**
- **libc: Make sure C23 versions of strtol(), sscanf() are not used**

src/basic/locale-util.c

@@ -7,7 +7,12 @@
 #include <sys/stat.h>
 #include <unistd.h>
 
+#ifndef __GLIBC__
+#include "sd-dlopen.h"
+#endif
+
 #include "dirent-util.h"
+#include "dlfcn-util.h"
 #include "env-util.h"
 #include "fd-util.h"
 #include "fileio.h"
@@ -22,6 +27,32 @@
 #include "strv.h"
 #include "utf8.h"
 
+#ifdef __GLIBC__
+DLSYM_PROTOTYPE(dgettext) = dgettext;
+#else
+DLSYM_PROTOTYPE(dgettext) = NULL;
+#endif
+
+int dlopen_libintl(int log_level) {
+#ifdef __GLIBC__
+        return 1;
+#else
+        static void *libintl_dl = NULL;
+
+        SD_ELF_NOTE_DLOPEN(
+                        "intl",
+                        "Support for message translation via gettext",
+                        SD_ELF_NOTE_DLOPEN_PRIORITY_SUGGESTED,
+                        "libintl.so.8");
+
+        return dlopen_many_sym_or_warn(
+                        &libintl_dl,
+                        "libintl.so.8",
+                        log_level,
+                        DLSYM_ARG(dgettext));
+#endif
+}
+
 static char* normalize_locale(const char *name) {
         const char *e;
 

src/basic/locale-util.h

@@ -1,9 +1,18 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
+#include <libintl.h>    /* IWYU pragma: export */
 #include <locale.h>     /* IWYU pragma: export */
 
 #include "basic-forward.h"
+#include "dlfcn-util.h"
+
+/* format_arg(2) propagates the format-string nature of the second argument to the return value, so that
+ * printf(_("Hello %s"), name) still gets checked. It survives both DLSYM_PROTOTYPE's typeof() and the
+ * ternary in _() below — verified on gcc and clang. */
+extern DLSYM_PROTOTYPE(dgettext) __attribute__((format_arg(2)));
+
+int dlopen_libintl(int log_level);
 
 typedef enum LocaleVariable {
         /* We don't list LC_ALL here on purpose. People should be
@@ -31,7 +40,9 @@ int get_locales(char ***ret);
 bool locale_is_valid(const char *name);
 int locale_is_installed(const char *name);
 
-#define _(String) dgettext(GETTEXT_PACKAGE, String)
+/* Falls back to the untranslated string if dlopen_libintl() hasn't run or has failed, so callers don't have
+ * to gate every translatable message on a runtime check. */
+#define _(String) (sym_dgettext ? sym_dgettext(GETTEXT_PACKAGE, (String)) : (String))
 #define N_(String) String
 
 bool is_locale_utf8(void);

src/basic/lock-util.c

@@ -1,7 +1,6 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
 #include <fcntl.h>
-#include <signal.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -227,25 +226,6 @@ int lock_generic_with_timeout(int fd, LockType type, int operation, usec_t timeo
         if (r < 0)
                 return log_error_errno(r, "Failed to flock block device in child process: %m");
         if (r == 0) {
-                struct sigevent sev = {
-                        .sigev_notify = SIGEV_SIGNAL,
-                        .sigev_signo = SIGALRM,
-                };
-                timer_t id;
-
-                if (timer_create(CLOCK_MONOTONIC, &sev, &id) < 0) {
-                        log_error_errno(errno, "Failed to allocate CLOCK_MONOTONIC timer: %m");
-                        _exit(EXIT_FAILURE);
-                }
-
-                struct itimerspec its = {};
-                timespec_store(&its.it_value, timeout);
-
-                if (timer_settime(id, /* flags= */ 0, &its, NULL) < 0) {
-                        log_error_errno(errno, "Failed to start CLOCK_MONOTONIC timer: %m");
-                        _exit(EXIT_FAILURE);
-                }
-
                 if (lock_generic(fd, type, operation) < 0) {
                         log_error_errno(errno, "Unable to get an exclusive lock on the device: %m");
                         _exit(EXIT_FAILURE);
@@ -255,7 +235,7 @@ int lock_generic_with_timeout(int fd, LockType type, int operation, usec_t timeo
         }
 
         siginfo_t status;
-        r = pidref_wait_for_terminate(&pidref, &status);
+        r = pidref_wait_for_terminate_full(&pidref, timeout, &status);
         if (r < 0)
                 return r;
 
@@ -270,11 +250,6 @@ int lock_generic_with_timeout(int fd, LockType type, int operation, usec_t timeo
                 return 0;
 
         case CLD_KILLED:
-                if (status.si_status == SIGALRM)
-                        return -ETIMEDOUT;
-
-                _fallthrough_;
-
         case CLD_DUMPED:
                 return -EPROTO;
 

src/basic/meson.build

@@ -212,15 +212,12 @@ libbasic_static = static_library(
         include_directories : basic_includes,
         implicit_include_directories : false,
         dependencies : [libbzip2_cflags,
-                        libdl,
                         libgcrypt_cflags,
                         liblz4_cflags,
                         libm,
-                        librt,
                         libxz_cflags,
                         libz_cflags,
                         libzstd_cflags,
-                        threads,
                         userspace],
         c_args : ['-fvisibility=default'],
         build_by_default : false)