auto merge of #11750 : bnoordhuis/rust/follow-rustc-symlink, r=thestinger

Before this commit, rustc looked in `dirname $0`/../lib for libraries
but that doesn't work when rustc is invoked through a symlink.

This commit makes rustc look in `dirname $(readlink $0)`/../lib, i.e.
it first canonicalizes the symlink before walking up the directory tree.

Fixes #3632.

src/etc/check-summary.py

@@ -1,6 +1,7 @@
 #!/usr/bin/env python
 # xfail-license
 
+import glob
 import sys
 
 if __name__ == '__main__':
@@ -24,7 +25,8 @@ if __name__ == '__main__':
     def count(t):
         return sum(map(lambda (f, s): len(s.get(t, [])), summaries))
     logfiles = sys.argv[1:]
-    map(summarise, logfiles)
+    for files in map(glob.glob, logfiles):
+        map(summarise, files)
     ok = count('ok')
     failed = count('failed')
     ignored = count('ignored')

src/librustc/metadata/filesearch.rs

@@ -160,8 +160,24 @@ fn make_rustpkg_target_lib_path(dir: &Path,
 }
 
 pub fn get_or_default_sysroot() -> Path {
-    match os::self_exe_path() {
-      option::Some(p) => { let mut p = p; p.pop(); p }
+    // Follow symlinks.  If the resolved path is relative, make it absolute.
+    fn canonicalize(path: Option<Path>) -> Option<Path> {
+        path.and_then(|mut path|
+            match io::io_error::cond.trap(|_| ()).inside(|| fs::readlink(&path)) {
+                Some(canon) => {
+                    if canon.is_absolute() {
+                        Some(canon)
+                    } else {
+                        path.pop();
+                        Some(path.join(canon))
+                    }
+                },
+                None => Some(path),
+            })
+    }
+
+    match canonicalize(os::self_exe_name()) {
+      option::Some(p) => { let mut p = p; p.pop(); p.pop(); p }
       option::None => fail!("can't determine value for sysroot")
     }
 }

src/libstd/os.rs

@@ -337,9 +337,9 @@ pub fn dll_filename(base: &str) -> ~str {
     format!("{}{}{}", consts::DLL_PREFIX, base, consts::DLL_SUFFIX)
 }
 
-/// Optionally returns the filesystem path to the current executable which is
+/// Optionally returns the filesystem path of the current executable which is
 /// running. If any failure occurs, None is returned.
-pub fn self_exe_path() -> Option<Path> {
+pub fn self_exe_name() -> Option<Path> {
 
     #[cfg(target_os = "freebsd")]
     fn load_self() -> Option<~[u8]> {
@@ -402,7 +402,14 @@ pub fn self_exe_path() -> Option<Path> {
         }
     }
 
-    load_self().and_then(|path| Path::new_opt(path).map(|mut p| { p.pop(); p }))
+    load_self().and_then(Path::new_opt)
+}
+
+/// Optionally returns the filesystem path to the current executable which is
+/// running. Like self_exe_name() but without the binary's name.
+/// If any failure occurs, None is returned.
+pub fn self_exe_path() -> Option<Path> {
+    self_exe_name().map(|mut p| { p.pop(); p })
 }
 
 /**
@@ -1310,6 +1317,17 @@ mod tests {
         assert_eq!(getenv(n), option::Some(s));
     }
 
+    #[test]
+    fn test_self_exe_name() {
+        let path = os::self_exe_name();
+        assert!(path.is_some());
+        let path = path.unwrap();
+        debug!("{:?}", path.clone());
+
+        // Hard to test this function
+        assert!(path.is_absolute());
+    }
+
     #[test]
     fn test_self_exe_path() {
         let path = os::self_exe_path();