Index: vendor/libbase/file.cpp
--- vendor/libbase/file.cpp.orig
+++ vendor/libbase/file.cpp
@@ -26,6 +26,9 @@
 #include <sys/param.h>
 #include <sys/stat.h>
 #include <sys/types.h>
+#ifdef __OpenBSD__
+#include <sys/sysctl.h>
+#endif
 #include <unistd.h>
 
 #include <memory>
@@ -508,6 +511,48 @@ std::string GetExecutablePath() {
   return path;
 #elif defined(__EMSCRIPTEN__)
   abort();
+#elif defined(__OpenBSD__)
+  // Try /proc/curproc/file if procfs is mounted.
+  {
+    std::string path;
+    if (android::base::Readlink("/proc/curproc/file", &path) && !path.empty()) {
+      return path;
+    }
+  }
+  // Fall back to sysctl(KERN_PROC_ARGV) to recover argv[0] and resolve it.
+  {
+    int mib[4] = {CTL_KERN, KERN_PROC_ARGS, getpid(), KERN_PROC_ARGV};
+    size_t len = 0;
+    if (sysctl(mib, 4, nullptr, &len, nullptr, 0) != -1 && len > 0) {
+      std::vector<char> buf(len);
+      if (sysctl(mib, 4, buf.data(), &len, nullptr, 0) != -1) {
+        char* argv0 = reinterpret_cast<char**>(buf.data())[0];
+        if (argv0 != nullptr) {
+          if (argv0[0] == '/') {
+            return argv0;  // Already absolute.
+          }
+          // Search PATH directories for argv0.
+          if (const char* path_env = getenv("PATH")) {
+            const char* p = path_env;
+            while (*p) {
+              const char* q = strchr(p, ':');
+              size_t dirlen = q ? (size_t)(q - p) : strlen(p);
+              std::string full(p, dirlen);
+              full += '/';
+              full += argv0;
+              char resolved[PATH_MAX];
+              if (realpath(full.c_str(), resolved) != nullptr) {
+                return resolved;
+              }
+              p += dirlen;
+              if (*p == ':') ++p;
+            }
+          }
+        }
+      }
+    }
+  }
+  return "";
 #else
 #error unknown OS
 #endif