init: Add "export_rc" command to export env from a specified file

New export_rc command to import environment variables from
a specified file at the time the command is executed.

Differences between "import" and "export_rc":
1) export_rc can only import environment vars
2) export_rc is performed when the command
   is executed rather than at the time the
   command is parsed (i.e. "import")

Example:
in /init.rc:
    on post-fs
        export_rc /system/etc/init.xyz.rc

in /system/etc/init.xyz.rc:
    export LD_PRELOAD /system/lib/libxyz.so

Change-Id: If616dea5b508c27e9f7a95b5e9db696ecea2fdee

1 files changed, 19 insertions, 0 deletions

diff --git a/init/builtins.c b/init/builtins.c
index 5dfa215e..0d87274f 100644
--- a/init/builtins.c
+++ b/init/builtins.c
@@ -15,6 +15,7 @@
  */
 
 #include <sys/types.h>
+#include <sys/wait.h>
 #include <sys/stat.h>
 #include <fcntl.h>
 #include <unistd.h>
@@ -54,6 +55,7 @@
 void add_environment(const char *name, const char *value);
 
 extern int init_module(void *, unsigned long, const char *);
+extern int init_export_rc_file(const char *);
 
 static int write_file(const char *path, const char *value)
 {
@@ -221,6 +223,23 @@ int do_class_reset(int nargs, char **args)
     return 0;
 }
 
+int do_export_rc(int nargs, char **args)
+{
+        /* Import environments from a specified file.
+         * The file content is of the form:
+         *     export <env name> <value>
+         * e.g.
+         *     export LD_PRELOAD /system/lib/xyz.so
+         *     export PROMPT abcde
+         * Differences between "import" and "export_rc":
+         * 1) export_rc can only import environment vars
+         * 2) export_rc is performed when the command
+         *    is executed rather than at the time the
+         *    command is parsed (i.e. "import")
+         */
+    return init_export_rc_file(args[1]);
+}
+
 int do_domainname(int nargs, char **args)
 {
     return write_file("/proc/sys/kernel/domainname", args[1]);