lmkd: Support process types when registering a process

Add an optional process type field into lmkd registration protocol so that
applications can be distinguished from services.

Bug: 129011369
Test: boot and verify native service registration
Change-Id: Ie610b5d07cbe247a55ab31bc079ee5c5923bea11
Signed-off-by: Suren Baghdasaryan <[email protected]>

Author: surenbaghdasaryan

lmkd/include/lmkd.h

@@ -87,21 +87,33 @@ static inline size_t lmkd_pack_set_target(LMKD_CTRL_PACKET packet, struct lmk_ta
     return idx * sizeof(int);
 }
 
+/* Process types for lmk_procprio.ptype */
+enum proc_type {
+    PROC_TYPE_FIRST,
+    PROC_TYPE_APP = PROC_TYPE_FIRST,
+    PROC_TYPE_SERVICE,
+    PROC_TYPE_COUNT,
+};
+
 /* LMK_PROCPRIO packet payload */
 struct lmk_procprio {
     pid_t pid;
     uid_t uid;
     int oomadj;
+    enum proc_type ptype;
 };
 
 /*
  * For LMK_PROCPRIO packet get its payload.
  * Warning: no checks performed, caller should ensure valid parameters.
  */
-static inline void lmkd_pack_get_procprio(LMKD_CTRL_PACKET packet, struct lmk_procprio* params) {
+static inline void lmkd_pack_get_procprio(LMKD_CTRL_PACKET packet, int field_count,
+                                          struct lmk_procprio* params) {
     params->pid = (pid_t)ntohl(packet[1]);
     params->uid = (uid_t)ntohl(packet[2]);
     params->oomadj = ntohl(packet[3]);
+    /* if field is missing assume PROC_TYPE_APP for backward compatibility */
+    params->ptype = field_count > 3 ? (enum proc_type)ntohl(packet[4]) : PROC_TYPE_APP;
 }
 
 /*
@@ -113,7 +125,8 @@ static inline size_t lmkd_pack_set_procprio(LMKD_CTRL_PACKET packet, struct lmk_
     packet[1] = htonl(params->pid);
     packet[2] = htonl(params->uid);
     packet[3] = htonl(params->oomadj);
-    return 4 * sizeof(int);
+    packet[4] = htonl((int)params->ptype);
+    return 5 * sizeof(int);
 }
 
 /* LMK_PROCREMOVE packet payload */

lmkd/lmkd.c

@@ -876,7 +876,7 @@ static void remove_claims(pid_t pid) {
     }
 }
 
-static void cmd_procprio(LMKD_CTRL_PACKET packet, struct ucred *cred) {
+static void cmd_procprio(LMKD_CTRL_PACKET packet, int field_count, struct ucred *cred) {
     struct proc *procp;
     char path[LINE_MAX];
     char val[20];
@@ -886,14 +886,19 @@ static void cmd_procprio(LMKD_CTRL_PACKET packet, struct ucred *cred) {
     struct passwd *pwdrec;
     int tgid;
 
-    lmkd_pack_get_procprio(packet, &params);
+    lmkd_pack_get_procprio(packet, field_count, &params);
 
     if (params.oomadj < OOM_SCORE_ADJ_MIN ||
         params.oomadj > OOM_SCORE_ADJ_MAX) {
         ALOGE("Invalid PROCPRIO oomadj argument %d", params.oomadj);
         return;
     }
 
+    if (params.ptype < PROC_TYPE_FIRST || params.ptype >= PROC_TYPE_COUNT) {
+        ALOGE("Invalid PROCPRIO process type argument %d", params.ptype);
+        return;
+    }
+
     /* Check if registered process is a thread group leader */
     tgid = proc_get_tgid(params.pid);
     if (tgid >= 0 && tgid != params.pid) {
@@ -920,7 +925,8 @@ static void cmd_procprio(LMKD_CTRL_PACKET packet, struct ucred *cred) {
         return;
     }
 
-    if (per_app_memcg) {
+    /* lmkd should not change soft limits for services */
+    if (params.ptype == PROC_TYPE_APP && per_app_memcg) {
         if (params.oomadj >= 900) {
             soft_limit_mult = 0;
         } else if (params.oomadj >= 800) {
@@ -1298,9 +1304,10 @@ static void ctrl_command_handler(int dsock_idx) {
         cmd_target(targets, packet);
         break;
     case LMK_PROCPRIO:
-        if (nargs != 3)
+        /* process type field is optional for backward compatibility */
+        if (nargs < 3 || nargs > 4)
             goto wronglen;
-        cmd_procprio(packet, &cred);
+        cmd_procprio(packet, nargs, &cred);
         break;
     case LMK_PROCREMOVE:
         if (nargs != 1)