eagle: new package

Eagle is a schematic capture and PCB layout program from CadSoft. This
is proprietary software; CadSoft provide a self-extracting shell script
with embedded tarball of the prebuilt application.

Add the latest Eagle version, 6.4.0.

I've added a small LD_PRELOAD library that redirects operations on the
license file from <eagle_install_path>/bin/eagle.key to
$HOME/.eagle.key. Without this Eagle will never get past the license
dialog (because you cannot write to the nix store).

Eagle also has issues copying its example projects to other locations;
it seems that it wants to preserve the read-only permissions from the
source over to the destination. Because of this it cannot complete the
copy operation because it cannot write the project files into to the
(read-only) project directory it just created. So wrap chmod by OR'ing
in the write-by-owner bit.

2 files changed, 220 insertions, 0 deletions

diff --git a/pkgs/applications/science/electronics/eagle/default.nix b/pkgs/applications/science/electronics/eagle/default.nix
new file mode 100644
index 000000000000..04c9a9b79ec5
--- /dev/null
+++ b/pkgs/applications/science/electronics/eagle/default.nix
@@ -0,0 +1,86 @@
+{ stdenv, fetchurl, makeDesktopItem, patchelf, zlib, freetype, fontconfig
+, openssl, libXrender, libXrandr, libXcursor, libX11, libXext, libXi
+}:
+
+let
+
+  libPath = stdenv.lib.makeLibraryPath
+    [ zlib freetype fontconfig openssl libXrender libXrandr libXcursor libX11
+      libXext libXi
+    ];
+
+in
+
+stdenv.mkDerivation rec {
+  name = "eagle-${version}";
+  version = "6.4.0";
+
+  src = fetchurl {
+    url = "ftp://ftp.cadsoft.de/eagle/program/6.4/eagle-lin-${version}.run";
+    sha256 = "0jb44dsq4cl9rx5nam6rxsw9fsmm6fsksv9s544p2zrwnad2x2i8";
+  };
+
+  desktopItem = makeDesktopItem {
+    name = "Eagle";
+    exec = "eagle";
+    icon = "eagle";
+    comment = "Schematic capture and PCB layout";
+    desktopName = "Eagle";
+    genericName = "Schematic editor";
+    categories = "Application;Development;";
+  };
+
+  buildInputs =
+    [ patchelf zlib freetype fontconfig openssl libXrender libXrandr libXcursor
+      libX11 libXext libXi
+    ];
+
+  phases = [ "installPhase" ];
+
+  # NOTES:
+  # Eagle for Linux comes as a self-extracting shell script with embedded
+  # tarball. The tarball data (.tar.bz2) starts after a __DATA__ marker.
+  #
+  # Eagle apparently doesn't like binary patching. This is what happens:
+  #   $ ./result/eagle-6.4.0/bin/eagle
+  #   argv[0] (/home/bfo/nixpkgs/result/eagle-6.4.0/bin/eagle) is not the currently executed program version!
+  installPhase = ''
+    # Extract eagle tarball
+    mkdir "$out"
+    sed '1,/^__DATA__$/d' "$src" | tar -xjf - -C "$out"
+
+    # Install manpage
+    mkdir -p "$out"/share/man/man1
+    ln -s "$out"/eagle-${version}/doc/eagle.1 "$out"/share/man/man1/eagle.1
+
+    # Build LD_PRELOAD library that redirects license file access to the home
+    # directory of the user
+    mkdir -p "$out"/lib
+    gcc -shared -fPIC -DEAGLE_PATH=\"$out/eagle-${version}\" ${./eagle_fixer.c} -o "$out"/lib/eagle_fixer.so -ldl
+
+    # Make wrapper script
+    dynlinker="$(cat $NIX_GCC/nix-support/dynamic-linker)"
+    mkdir -p "$out"/bin
+    cat > "$out"/bin/eagle << EOF
+    #!${stdenv.shell}
+    export LD_LIBRARY_PATH="${stdenv.gcc.gcc}/lib:${libPath}"
+    export LD_PRELOAD="$out/lib/eagle_fixer.so"
+    exec "$dynlinker" "$out/eagle-${version}/bin/eagle" "\$@"
+    EOF
+    chmod a+x "$out"/bin/eagle
+
+    # Make desktop item
+    mkdir -p "$out"/share/applications
+    cp "$desktopItem"/share/applications/* "$out"/share/applications/
+    mkdir -p "$out"/share/icons
+    ln -s "$out/eagle-${version}/bin/eagleicon50.png" "$out"/share/icons/eagle.png
+  '';
+
+  meta = with stdenv.lib; {
+    description = "Schematic editor and PCB layout tool from CadSoft";
+    homepage = http://www.cadsoftusa.com/;
+    license = licenses.unfree;
+    platforms = platforms.linux;
+    maintainers = [ maintainers.bjornfor ];
+  };
+}
diff --git a/pkgs/applications/science/electronics/eagle/eagle_fixer.c b/pkgs/applications/science/electronics/eagle/eagle_fixer.c
new file mode 100644
index 000000000000..da9da4dcbd3a
--- /dev/null
+++ b/pkgs/applications/science/electronics/eagle/eagle_fixer.c
@@ -0,0 +1,134 @@
+/*
+ * LD_PRELOAD trick to make Eagle (schematic editor and PCB layout tool from
+ * CadSoft) work from a read-only installation directory.
+ *
+ * When Eagle starts, it looks for the license file in <eagle>/bin/eagle.key
+ * (where <eagle> is the install path). If eagle.key is not found, Eagle checks
+ * for write access to <eagle>/bin/, shows a license dialog to the user and
+ * then attempts to write a license file to <eagle>/bin/.
+ *
+ * This will of course fail when Eagle is installed in the read-only Nix store.
+ * Hence this library that redirects accesses to the those paths in the
+ * following way:
+ *
+ *   <eagle>/bin              => $HOME
+ *   <eagle>/bin/eagle.key    => $HOME/.eagle.key
+ *
+ * Also, if copying an example project to ~/eagle/ (in the Eagle GUI), Eagle
+ * chmod's the destination with read-only permission bits (presumably because
+ * the source is read-only) and fails to complete the copy operation.
+ * Therefore, the mode argument in calls to chmod() is OR'ed with the S_IWUSR
+ * bit (write by owner).
+ *
+ * Usage:
+ *   gcc -shared -fPIC -DEAGLE_PATH="$out/eagle-${version}" eagle_fixer.c -o eagle_fixer.so -ldl
+ *   LD_PRELOAD=$PWD/eagle_fixer.so ./result/bin/eagle
+ *
+ * To see the paths that are modified at runtime, set the environment variable
+ * EAGLE_FIXER_DEBUG to 1.
+ */
+
+#define _GNU_SOURCE
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <dlfcn.h>
+#include <limits.h>
+#include <sys/stat.h>
+
+#ifndef EAGLE_PATH
+#error Missing EAGLE_PATH, path to the eagle-${version} installation directory.
+#endif
+
+typedef FILE *(*fopen_func_t)(const char *path, const char *mode);
+typedef int (*access_func_t)(const char *pathname, int mode);
+typedef int (*chmod_func_t)(const char *path, mode_t mode);
+
+/*
+ * Map <eagle>/bin to $HOME and <eagle>/bin/eagle.key to $HOME/.eagle.key
+ *
+ * Path is truncated if bigger than PATH_MAX. It's not threadsafe, but that's
+ * OK.
+ */
+static const char *redirect(const char *pathname)
+{
+	static char buffer[PATH_MAX];
+	const char *homepath;
+	const char *new_path;
+	static int have_warned;
+
+	homepath = getenv("HOME");
+	if (!homepath) {
+		homepath = "/";
+		if (!have_warned && getenv("EAGLE_FIXER_DEBUG")) {
+			fprintf(stderr, "eagle_fixer: HOME is unset, using \"/\" (root) instead.\n");
+			have_warned = 1;
+		}
+	}
+
+	new_path = pathname;
+	if (strcmp(EAGLE_PATH "/bin", pathname) == 0) {
+		/* redirect to $HOME */
+		new_path = homepath;
+	} else if (strcmp(EAGLE_PATH "/bin/eagle.key", pathname) == 0) {
+		/* redirect to $HOME/.eagle.key */
+		snprintf(buffer, PATH_MAX, "%s/.eagle.key", homepath);
+		buffer[PATH_MAX-1] = '\0';
+		new_path = buffer;
+	}
+
+	return new_path;
+}
+
+FILE *fopen(const char *pathname, const char *mode)
+{
+	FILE *fp;
+	const char *path;
+	fopen_func_t orig_fopen;
+
+	orig_fopen = (fopen_func_t)dlsym(RTLD_NEXT, "fopen");
+	path = redirect(pathname);
+	fp = orig_fopen(path, mode);
+
+	if (path != pathname && getenv("EAGLE_FIXER_DEBUG")) {
+		fprintf(stderr, "eagle_fixer: fopen(\"%s\", \"%s\") => \"%s\": fp=%p\n", pathname, mode, path, fp);
+	}
+
+	return fp;
+}
+
+int access(const char *pathname, int mode)
+{
+	int ret;
+	const char *path;
+	access_func_t orig_access;
+
+	orig_access = (access_func_t)dlsym(RTLD_NEXT, "access");
+	path = redirect(pathname);
+	ret = orig_access(path, mode);
+
+	if (path != pathname && getenv("EAGLE_FIXER_DEBUG")) {
+		fprintf(stderr, "eagle_fixer: access(\"%s\", %d) => \"%s\": ret=%d\n", pathname, mode, path, ret);
+	}
+
+	return ret;
+}
+
+int chmod(const char *pathname, mode_t mode)
+{
+	int ret;
+	mode_t new_mode;
+	chmod_func_t orig_chmod;
+
+	orig_chmod = (chmod_func_t)dlsym(RTLD_NEXT, "chmod");
+	new_mode = mode | S_IWUSR;
+	ret = orig_chmod(pathname, new_mode);
+
+	if (getenv("EAGLE_FIXER_DEBUG")) {
+		fprintf(stderr, "eagle_fixer: chmod(\"%s\", %o) => %o: ret=%d\n", pathname, mode, new_mode, ret);
+	}
+
+	return ret;
+}