init: cleanup environment handling

Init keep its own copy of the environment that it uses for execve when
starting services.  This is unnecessary however as libc already has
functions that mutate the environment and the environment that init
uses is clean for starting services.  This change removes init's copy
of the environment and uses the libc functions instead.

This also makes small clean-up to the way the Service class stores
service specific environment variables.

Test: boot bullhead
Change-Id: I7c98a0b7aac9fa8f195ae33bd6a7515bb56faf78

1 files changed, 2 insertions, 36 deletions

diff --git a/init/init.cpp b/init/init.cpp
index d0afac11d..e1bd3a2cb 100644
--- a/init/init.cpp
+++ b/init/init.cpp
@@ -71,8 +71,6 @@ static char qemu[32];
 
 std::string default_console = "/dev/console";
 
-const char *ENV[32];
-
 static int epoll_fd = -1;
 
 static std::unique_ptr<Timer> waiting_for_prop(nullptr);
@@ -126,38 +124,6 @@ void register_epoll_handler(int fd, void (*fn)()) {
     }
 }
 
-/* add_environment - add "key=value" to the current environment */
-int add_environment(const char *key, const char *val)
-{
-    size_t n;
-    size_t key_len = strlen(key);
-
-    /* The last environment entry is reserved to terminate the list */
-    for (n = 0; n < (arraysize(ENV) - 1); n++) {
-
-        /* Delete any existing entry for this key */
-        if (ENV[n] != NULL) {
-            size_t entry_key_len = strcspn(ENV[n], "=");
-            if ((entry_key_len == key_len) && (strncmp(ENV[n], key, entry_key_len) == 0)) {
-                free((char*)ENV[n]);
-                ENV[n] = NULL;
-            }
-        }
-
-        /* Add entry if a free slot is available */
-        if (ENV[n] == NULL) {
-            char* entry;
-            asprintf(&entry, "%s=%s", key, val);
-            ENV[n] = entry;
-            return 0;
-        }
-    }
-
-    LOG(ERROR) << "No env. room to store: '" << key << "':'" << val << "'";
-
-    return -1;
-}
-
 bool start_waiting_for_property(const char *name, const char *value)
 {
     if (waiting_for_prop) {
@@ -429,8 +395,6 @@ int main(int argc, char** argv) {
         install_reboot_signal_handlers();
     }
 
-    add_environment("PATH", _PATH_DEFPATH);
-
     bool is_first_stage = (getenv("INIT_SECOND_STAGE") == nullptr);
 
     if (is_first_stage) {
@@ -439,6 +403,8 @@ int main(int argc, char** argv) {
         // Clear the umask.
         umask(0);
 
+        clearenv();
+        setenv("PATH", _PATH_DEFPATH, 1);
         // Get the basic filesystem setup we need put together in the initramdisk
         // on / and then we'll let the rc file figure out the rest.
         mount("tmpfs", "/dev", "tmpfs", MS_NOSUID, "mode=0755");