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

3 files changed, 81 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]);
diff --git a/init/init_parser.c b/init/init_parser.c
index a2cd06ab..79bdbb87 100644
--- a/init/init_parser.c
+++ b/init/init_parser.c
@@ -51,6 +51,8 @@ static void parse_line_service(struct parse_state *state, int nargs, char **args
 static void *parse_action(struct parse_state *state, int nargs, char **args);
 static void parse_line_action(struct parse_state *state, int nargs, char **args);
 
+void add_environment(const char *name, const char *value);
+
 #define SECTION 0x01
 #define COMMAND 0x02
 #define OPTION  0x04
@@ -100,6 +102,7 @@ int lookup_keyword(const char *s)
     case 'e':
         if (!strcmp(s, "xec")) return K_exec;
         if (!strcmp(s, "xport")) return K_export;
+        if (!strcmp(s, "xport_rc")) return K_export_rc;
         break;
     case 'g':
         if (!strcmp(s, "roup")) return K_group;
@@ -409,6 +412,63 @@ int init_parse_config_file(const char *fn)
     return 0;
 }
 
+typedef enum {
+    ENV_NOTREADY,
+    ENV_NAME,
+    ENV_VALUE,
+    ENV_WAITFORNEXTLINE,
+} export_rc_state_t;
+
+int init_export_rc_file(const char *fn)
+{
+    char *data;
+    struct parse_state state;
+    char *env = NULL;
+    export_rc_state_t env_state = ENV_NOTREADY;
+
+    data = read_file(fn, 0);
+    if (!data) return -1;
+
+    state.filename = fn;
+    state.line = 0;
+    state.ptr = data;
+    state.nexttoken = 0;
+    state.parse_line = parse_line_no_op;
+    for (;;) {
+        switch (next_token(&state)) {
+        case T_EOF:
+            free(data);
+            return 0;
+        case T_NEWLINE:
+            env_state = ENV_NOTREADY;
+            break;
+        case T_TEXT:
+            switch (env_state) {
+            case ENV_NOTREADY:
+                if (strcmp(state.text, "export") == 0) {
+                    env_state = ENV_NAME;
+                } else {
+                    env_state = ENV_WAITFORNEXTLINE;
+                }
+                break;
+            case ENV_NAME:
+                env = state.text;
+                env_state = ENV_VALUE;
+                break;
+            case ENV_VALUE:
+                add_environment(env, state.text);
+                env_state = ENV_WAITFORNEXTLINE;
+                break;
+            default:
+                break;
+            }
+            break;
+        }
+    }
+
+    return 0;
+}
+
 static int valid_name(const char *name)
 {
     if (strlen(name) > 16) {
diff --git a/init/keywords.h b/init/keywords.h
index b3f6ebc4..66a165ff 100644
--- a/init/keywords.h
+++ b/init/keywords.h
@@ -8,6 +8,7 @@ int do_class_reset(int nargs, char **args);
 int do_domainname(int nargs, char **args);
 int do_exec(int nargs, char **args);
 int do_export(int nargs, char **args);
+int do_export_rc(int nargs, char **args);
 int do_hostname(int nargs, char **args);
 int do_ifup(int nargs, char **args);
 int do_insmod(int nargs, char **args);
@@ -55,6 +56,7 @@ enum {
     KEYWORD(domainname,  COMMAND, 1, do_domainname)
     KEYWORD(exec,        COMMAND, 1, do_exec)
     KEYWORD(export,      COMMAND, 2, do_export)
+    KEYWORD(export_rc,   COMMAND, 1, do_export_rc)
     KEYWORD(group,       OPTION,  0, 0)
     KEYWORD(hostname,    COMMAND, 1, do_hostname)
     KEYWORD(ifup,        COMMAND, 1, do_ifup)