[libbluray-devel] [PATCH 1/2] Get the correct java home on macOS

[Marvin Scholz]

On macOS apparently the only way to get the correct
path to the java home for the currently active SDK as
selected by the user is to use the /usr/libexec/java_home
tool.
---
It turned out the previous patchset actually still did work fine in
all cases, so this one does not use popen/pclose at all anymore,
which hopefully works in all cases.

Additionally the check if JLI was loaded properly was done the other
way around, so it would log that it was not able to load JLI when it
actually was, which is fixed in this version of the second patch.

 src/libbluray/bdj/bdj.c | 89 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 89 insertions(+)

diff --git a/src/libbluray/bdj/bdj.c b/src/libbluray/bdj/bdj.c
index d3d4c43..1a03be6 100644
--- a/src/libbluray/bdj/bdj.c
+++ b/src/libbluray/bdj/bdj.c
@@ -39,6 +39,13 @@
 #include <stdlib.h>
 #include <string.h>
 
+#ifdef __APPLE__
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <limits.h>
+#include <unistd.h>
+#endif
+
 #ifdef _WIN32
 #include <windows.h>
 #include <winreg.h>
@@ -174,6 +181,75 @@ static inline char *_utf8_to_cp(const char *utf8)
 }
 #endif
 
+#if defined(__APPLE__) && !defined(HAVE_BDJ_J2ME)
+
+#define MACOS_JAVA_HOME "/usr/libexec/java_home"
+static char *_java_home_macos()
+{
+    static char result[PATH_MAX] = "";
+
+    if (result[0])
+        return result;
+
+    pid_t java_home_pid;
+    int fd[2], exitcode;
+
+    if (pipe(fd)) {
+        BD_DEBUG(DBG_BDJ | DBG_CRIT, "unable to set up pipes\n");
+        return NULL;
+    }
+
+    switch (java_home_pid = vfork())
+    {
+        case -1:
+            BD_DEBUG(DBG_BDJ | DBG_CRIT, "vfork failed\n");
+            return NULL;
+
+        case 0:
+            if (dup2(fd[1], STDOUT_FILENO) == -1) {
+                BD_DEBUG(DBG_BDJ | DBG_CRIT, "unable to dup2 fd[1]\n");
+                exit(-1);
+            }
+
+            close(fd[1]);
+            close(fd[0]);
+
+            execl(MACOS_JAVA_HOME, MACOS_JAVA_HOME);
+
+            BD_DEBUG(DBG_BDJ | DBG_CRIT,
+                     "unable to execute " MACOS_JAVA_HOME "\n");
+
+            exit(-1);
+
+        default:
+            close(fd[1]);
+
+            for (int len = 0; ;) {
+                int n = read(fd[0], result + len, sizeof result - len);
+                if (n <= 0)
+                    break;
+
+                len += n;
+                result[len-1] = '\0';
+            }
+
+            waitpid(java_home_pid, &exitcode, 0);
+    }
+
+    if (result[0] == '\0' || exitcode) {
+        BD_DEBUG(DBG_BDJ | DBG_CRIT,
+                 "Unable to read path from " MACOS_JAVA_HOME "\n");
+        result[0] = '\0';
+        return NULL;
+    }
+
+    BD_DEBUG(DBG_BDJ, "macos java home: '%s'\n", result );
+    return result;
+}
+#undef MACOS_JAVA_HOME
+
+#endif
+
 static void *_jvm_dlopen(const char *java_home, const char *jvm_dir, const char *jvm_lib)
 {
     if (java_home) {
@@ -210,6 +286,10 @@ static void *_load_jvm(const char **p_java_home)
     static const char  jvm_dir[]  = "jre\\bin\\server";
     static const char  jvm_lib[]  = "jvm";
 # else
+#  ifdef __APPLE__
+    static const char *jvm_path[] = {NULL, JDK_HOME};
+    static const char  jvm_dir[]  = "jre/lib/server";
+#  else
     static const char *jvm_path[] = {NULL, JDK_HOME,
                                      "/usr/lib/jvm/default-java",
                                      "/usr/lib/jvm/default",
@@ -220,6 +300,7 @@ static void *_load_jvm(const char **p_java_home)
                                      "/usr/lib/jvm/java-6-openjdk",
     };
     static const char  jvm_dir[]  = "jre/lib/" JAVA_ARCH "/server";
+#  endif
     static const char  jvm_lib[]  = "libjvm";
 # endif
 #endif
@@ -241,6 +322,14 @@ static void *_load_jvm(const char **p_java_home)
     }
 #endif
 
+#if defined(__APPLE__) && !defined(HAVE_BDJ_J2ME)
+    java_home = _java_home_macos();
+    if (java_home) {
+        *p_java_home = java_home;
+        return _jvm_dlopen(java_home, jvm_dir, jvm_lib);
+    }
+#endif
+
     BD_DEBUG(DBG_BDJ, "JAVA_HOME not set, trying default locations\n");
 
     /* try our pre-defined locations */
-- 
2.9.3 (Apple Git-75)