[libbluray-devel] Get the correct java home on macOS

[Marvin Scholz]

libbluray | branch: master | Marvin Scholz <epirat07 at gmail.com> | Thu Dec  8 03:47:00 2016 +0100| [34bce23f06e854162c75f15b25df91a73c5bd4af] | committer: hpi1

Get the correct java home on macOS

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.

> http://git.videolan.org/gitweb.cgi/libbluray.git/?a=commit;h=34bce23f06e854162c75f15b25df91a73c5bd4af
---

 src/libbluray/bdj/bdj.c | 85 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 85 insertions(+)

diff --git a/src/libbluray/bdj/bdj.c b/src/libbluray/bdj/bdj.c
index 3a75076..2a2e2e6 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>
@@ -177,6 +184,71 @@ 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) {
+                _exit(-1);
+            }
+
+            close(fd[1]);
+            close(fd[0]);
+
+            execl(MACOS_JAVA_HOME, MACOS_JAVA_HOME);
+
+            _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) {
@@ -234,6 +306,10 @@ 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",
@@ -244,6 +320,7 @@ 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
@@ -265,6 +342,14 @@ 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 */