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-rw-r--r--src/basic/dlfcn-util.c66
1 files changed, 66 insertions, 0 deletions
diff --git a/src/basic/dlfcn-util.c b/src/basic/dlfcn-util.c
new file mode 100644
index 0000000..8022f55
--- /dev/null
+++ b/src/basic/dlfcn-util.c
@@ -0,0 +1,66 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include "dlfcn-util.h"
+
+static int dlsym_many_or_warnv(void *dl, int log_level, va_list ap) {
+ void (**fn)(void);
+
+ /* Tries to resolve a bunch of function symbols, and logs an error about if it cannot resolve one of
+ * them. Note that this function possibly modifies the supplied function pointers if the whole
+ * operation fails. */
+
+ while ((fn = va_arg(ap, typeof(fn)))) {
+ void (*tfn)(void);
+ const char *symbol;
+
+ symbol = va_arg(ap, typeof(symbol));
+
+ tfn = (typeof(tfn)) dlsym(dl, symbol);
+ if (!tfn)
+ return log_full_errno(log_level,
+ SYNTHETIC_ERRNO(ELIBBAD),
+ "Can't find symbol %s: %s", symbol, dlerror());
+ *fn = tfn;
+ }
+
+ return 0;
+}
+
+int dlsym_many_or_warn_sentinel(void *dl, int log_level, ...) {
+ va_list ap;
+ int r;
+
+ va_start(ap, log_level);
+ r = dlsym_many_or_warnv(dl, log_level, ap);
+ va_end(ap);
+
+ return r;
+}
+
+int dlopen_many_sym_or_warn_sentinel(void **dlp, const char *filename, int log_level, ...) {
+ _cleanup_(dlclosep) void *dl = NULL;
+ int r;
+
+ if (*dlp)
+ return 0; /* Already loaded */
+
+ dl = dlopen(filename, RTLD_LAZY);
+ if (!dl)
+ return log_debug_errno(SYNTHETIC_ERRNO(EOPNOTSUPP),
+ "%s is not installed: %s", filename, dlerror());
+
+ log_debug("Loaded '%s' via dlopen()", filename);
+
+ va_list ap;
+ va_start(ap, log_level);
+ r = dlsym_many_or_warnv(dl, log_level, ap);
+ va_end(ap);
+
+ if (r < 0)
+ return r;
+
+ /* Note that we never release the reference here, because there's no real reason to. After all this
+ * was traditionally a regular shared library dependency which lives forever too. */
+ *dlp = TAKE_PTR(dl);
+ return 1;
+}