wip, some dynamic stuff works

[ginge.git] / loader / dl.c

diff --git a/loader/dl.c b/loader/dl.c
new file mode 100644 (file)
index 0000000..154e012
--- /dev/null
+++ b/loader/dl.c
@@ -0,0 +1,67 @@
+// vim:shiftwidth=2:expandtab
+#define _GNU_SOURCE
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/mman.h>
+#include <dlfcn.h>
+#include "header.h"
+
+#define DL
+#include "override.c"
+
+__attribute__((constructor))
+static void ginge_init(void)
+{
+  unsigned int lowest_segment = (unsigned int)-1;
+  unsigned int start, end;
+  int i, ret;
+  FILE *f;
+
+  for (i = 0; i < ARRAY_SIZE(real_funcs_np); i++) {
+    *real_funcs_np[i].func_ptr = dlsym(RTLD_NEXT, real_funcs_np[i].name);
+    if (*real_funcs_np[i].func_ptr == NULL) {
+      fprintf(stderr, "dlsym %s: %s\n", real_funcs_np[i].name, dlerror());
+      exit(1);
+    }
+    // dbg("%p %s\n", *real_funcs_np[i].func_ptr, real_funcs_np[i].name);
+  }
+
+  f = fopen("/proc/self/maps", "r");
+  if (f == NULL) {
+    perror("open /proc/self/maps");
+    exit(1);
+  }
+
+  ret = fscanf(f, "%x-%x %*s %*s %*s %*s %*s\n", &start, &end);
+  if (ret != 2) {
+    perror("parse maps");
+    exit(1);
+  }
+  lowest_segment = start;
+
+  // assume first entry lists program's text section.
+  // unprotect it in case we need some patching.
+  ret = mprotect((void *)start, end - start, PROT_READ|PROT_WRITE|PROT_EXEC);
+  if (ret != 0)
+    perror("warning: mprotect");
+
+  while (1) {
+    ret = fscanf(f, "%x-%*s %*s %*s %*s %*s %*s\n", &start);
+    if (ret <= 0)
+      break;
+
+    if (start < lowest_segment)
+      lowest_segment = start;
+  }
+
+#if 0
+  rewind(f);
+  char buff[256];
+  while (fgets(buff, sizeof(buff), f))
+    fputs(buff, stdout);
+#endif
+  fclose(f);
+
+  emu_init((void *)lowest_segment);
+}
+