kit

commit 3ad7ea9ac8a11b814c0288fb0ec7f35cc4b20032
parent 9242af272b569d2335834ab5c18eb2130e870e46
Author: Ryan Sepassi <rsepassi@gmail.com>
Date:   Tue,  9 Jun 2026 08:59:39 -0700

driver/runtime: resolve rt support dir from the real image path

The rt support-dir search derived <bindir>/../rt and <bindir>/support/rt by
splitting argv[0]. That fails when argv[0] is not a usable path -- a bare
program name when kit is on PATH, a relative invocation, or a tool symlink
whose directory holds no rt -- leaving only the cwd-relative ./rt. Fall back to
the actual image path (driver_self_exe_path: GetModuleFileNameW on Windows,
/proc/self/exe on Linux, ...) and retry the binary-relative roots against it.
argv[0] is still tried first, so POSIX behavior is unchanged; the fallback is
what makes <bindir>/support/rt resolve when kit.exe is invoked by bare name on
Windows (verified on the VM). tool_path (stat'd for rt-archive cache
invalidation) now holds an owned dup of whichever path located rt, freed in
driver_runtime_support_fini.

Diffstat:
M
driver/lib/runtime.c
 | 
36
++++++++++++++++++++++++++++++++----
M
driver/lib/runtime.h
 | 
5
+++++

2 files changed, 37 insertions(+), 4 deletions(-)
diff --git a/driver/lib/runtime.c b/driver/lib/runtime.c
@@ -362,20 +362,43 @@ int driver_runtime_resolve(DriverEnv* env, const char* explicit_support_dir,
   DriverRuntimeSupport zero = {0};
   *out = zero;
 
+  char* self = NULL;
+  size_t self_size = 0;
+  const char* tool = argv0;
+
   if (explicit_support_dir) {
     rc = rt_try_support_root(env, explicit_support_dir, out);
   } else if (rt_try_support_root(env, ".", out) == 0) {
     rc = 0;
   } else if (rt_try_argv0_checkout_root(env, argv0, out) == 0) {
     rc = 0;
-  } else {
-    rc = rt_try_argv0_support(env, argv0, out);
+  } else if (rt_try_argv0_support(env, argv0, out) == 0) {
     /* rt found as a <bindir>/support/rt sibling: this is a distribution
      * install, not a build tree.  Mark it so the on-demand rt archive lands
      * in the user cache dir rather than polluting the install. */
-    if (rc == 0) out->install_layout = 1;
+    rc = 0;
+    out->install_layout = 1;
+  } else if (driver_self_exe_path(env, &self, &self_size) == 0 && self) {
+    /* argv[0] wasn't a usable path for binary-relative discovery — a bare
+     * program name when kit is on PATH, a relative invocation, or a tool
+     * symlink whose directory holds no rt. Retry against the real image path
+     * (GetModuleFileNameW on Windows, /proc/self/exe on Linux, ...). */
+    tool = self;
+    if (rt_try_argv0_checkout_root(env, self, out) == 0) {
+      rc = 0;
+    } else if (rt_try_argv0_support(env, self, out) == 0) {
+      rc = 0;
+      out->install_layout = 1;
+    } else {
+      rc = 1;
+    }
+  } else {
+    rc = 1;
   }
-  if (rc == 0) out->tool_path = argv0;
+  /* Own the located image path: it outlives `self`'s free below and the
+   * caller's argv, and is stat'd later for rt-archive cache invalidation. */
+  if (rc == 0) out->tool_path = rt_dup(env, tool, &out->tool_path_size);
+  if (self) driver_free(env, self, self_size);
   return rc;
 }
 
@@ -383,6 +406,11 @@ void driver_runtime_support_fini(DriverEnv* env, DriverRuntimeSupport* s) {
   rt_free_str(env, &s->include_dir, &s->include_dir_size);
   rt_free_str(env, &s->rt_root, &s->rt_root_size);
   rt_free_str(env, &s->support_root, &s->support_root_size);
+  if (s->tool_path && s->tool_path_size) {
+    driver_free(env, (void*)s->tool_path, s->tool_path_size);
+    s->tool_path = NULL;
+    s->tool_path_size = 0;
+  }
 }
 
 int driver_runtime_add_freestanding_headers(const DriverRuntimeSupport* s,
diff --git a/driver/lib/runtime.h b/driver/lib/runtime.h
@@ -13,7 +13,12 @@ typedef struct DriverRuntimeSupport {
   size_t rt_root_size;
   char* include_dir;
   size_t include_dir_size;
+  /* Owned dup of the kit image path that located the rt tree — argv[0] when it
+   * was a usable path, else the real self-exe path (GetModuleFileNameW /
+   * /proc/self/exe). Stat'd for rt-archive cache invalidation; freed by
+   * driver_runtime_support_fini. */
   const char* tool_path;
+  size_t tool_path_size;
   /* Set when rt was resolved as a <bindir>/support/rt sibling, i.e. a
    * distribution install rather than a source checkout.  Steers the on-demand
    * rt archive build toward the user cache dir instead of writing into the