1 files changed, 104 insertions, 0 deletions
diff --git a/ruby-runner.c b/ruby-runner.c
new file mode 100644
index 0000000000..295ef47cc3
--- /dev/null
+++ b/ruby-runner.c
@@ -0,0 +1,104 @@
+#define _POSIX_C_SOURCE 200809L
+#include "ruby/internal/config.h"
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+
+#ifdef _WIN32
+# error This feature is unnecessary on Windows in favor of SxS.
+#endif
+
+#include "ruby-runner.h"
+
+static void
+insert_env_path(const char *envname, const char *paths, size_t size, int prepend)
+{
+    const char *env = getenv(envname);
+    char c = 0;
+    size_t n = 0;
+
+    if (env) {
+        while ((c = *env) == PATH_SEP) ++env;
+        n = strlen(env);
+        while (n > 0 && env[n-1] == PATH_SEP) --n;
+    }
+    if (c) {
+        char *e = malloc(size+n+1);
+        size_t pos = 0;
+        if (prepend) {
+            if (size == n || (size < n && env[size] == PATH_SEP)) {
+                if (strncmp(paths, env, size) == 0) {
+                    free(e);
+                    return;
+                }
+            }
+            memcpy(e, paths, pos = size-1);
+            e[pos++] = PATH_SEP;
+        }
+        memcpy(e+pos, env, n);
+        pos += n;
+        if (!prepend) {
+            if (size == n || (size < n && env[n-size-1] == PATH_SEP)) {
+                if (strncmp(paths, &env[n-size], size) == 0) {
+                    free(e);
+                    return;
+                }
+            }
+            e[pos++] = PATH_SEP;
+            memcpy(e+pos, paths, size-1);
+            pos += size-1;
+        }
+        e[pos] = '\0';
+        env = e;
+    }
+    else {
+        env = paths;
+    }
+    setenv(envname, env, 1);
+}
+
+#define insert_env_path_lit(env, path, prep) \
+    insert_env_path(env, path, sizeof(path), prep)
+
+#define EXTOUT_DIR BUILDDIR"/"EXTOUT
+int
+main(int argc, char **argv)
+{
+    static const char builddir[] = BUILDDIR;
+    static const char rubypath[] = BUILDDIR"/"STRINGIZE(RUBY_INSTALL_NAME);
+    static const char rubylib[] =
+        ABS_SRCDIR"/lib"
+        PATH_SEPARATOR
+        EXTOUT_DIR"/common"
+        PATH_SEPARATOR
+        EXTOUT_DIR"/"ARCH
+        ;
+    const size_t dirsize = sizeof(builddir);
+    const size_t namesize = sizeof(rubypath) - dirsize;
+    const char *rubyname = rubypath + dirsize;
+    char *arg0 = argv[0], *p;
+
+    insert_env_path(LIBPATHENV, builddir, dirsize, 1);
+    insert_env_path("RUBYLIB", rubylib, sizeof(rubylib), 0);
+
+    if (!getenv("GEM_PATH")) {
+        insert_env_path_lit("GEM_PATH", ABS_SRCDIR"/.bundle", 1);
+        insert_env_path_lit("GEM_PATH", BUILDDIR"/.bundle", 1);
+        setenv("GEM_HOME", BUILDDIR"/.bundle", 0);
+    }
+
+    if (!(p = strrchr(arg0, '/'))) p = arg0; else p++;
+    if (strlen(p) < namesize - 1) {
+        argv[0] = malloc(p - arg0 + namesize);
+        memcpy(argv[0], arg0, p - arg0);
+        p = argv[0] + (p - arg0);
+    }
+    memcpy(p, rubyname, namesize);
+
+    execv(rubypath, argv);
+    perror(rubypath);
+    return -1;
+}