Resolve the executable path on Mac OS when sym-linked

runtime/bin/platform_macos.cc

Index: runtime/bin/platform_macos.cc
diff --git a/runtime/bin/platform_macos.cc b/runtime/bin/platform_macos.cc
index 702bf017806e811b78243ca729276b7c8cdc8872..d036304d47e2fcd2016c707b7b22e1abfa53b981 100644
--- a/runtime/bin/platform_macos.cc
+++ b/runtime/bin/platform_macos.cc
@@ -7,6 +7,7 @@
 
 #include <mach-o/dyld.h>
 
+#include "bin/file.h"
 #include "bin/platform.h"
 
 #include <crt_externs.h>  // NOLINT
@@ -91,6 +92,34 @@ char* Platform::ResolveExecutablePath() {
     free(path);
     return NULL;
   }
+  // If the path is a symbolic link resolve that link.
+  File::Type type = File::GetType(path, false);
+  if (type == File::kIsLink) {
+    char* target_path = File::LinkTarget(path);
+    free(path);
+    return target_path;
+  }
+  // If the directory of the executable is a symbolic link resolve that link.
+  char* last_slash = strrchr(path, '/');
+  if (last_slash != NULL && last_slash != path) {
+    // Split off the last slash and the executable.
+    *last_slash = '\0';
+    File::Type type = File::GetType(path, false);
+    if (type == File::kIsLink) {
+      // Resolve the directory and append the executable.
+      char* target_path = File::LinkTarget(path);
+      *last_slash = '/';
+      size_t new_path_len = strlen(target_path) + strlen(last_slash) + 1;
+      char* new_path = reinterpret_cast<char*>(malloc(new_path_len));
+      snprintf(new_path, new_path_len, "%s%s", target_path, last_slash);
+      free(path);
+      free(target_path);
+      return new_path;
+    } else {
+      // Directory was not a symbolic link re-construct the path.
+      *last_slash = '/';
+    }

[kustermann, 2015/06/08 08:22:25]

So this only handles symlinks to the binary itself or it's directory (which is
bin), but not to the sdk directory?

Furthermore it doesn't seem to handle symlinks to symlinks to actual binaries if
I see this correctly.

Can't you just use the File::GetCanonicalPath() function defined in this file?
The manpage indicates that it will resolve all '.' '..' and symlinks.

[Søren Gjesse, 2015/06/09 10:46:48]

Thanks Martin. This was a really crappy attempt to partly implement realpath.

+  }
   return path;
 }