aux/acpi: do not expose empty files

diff --git a/sys/src/cmd/aux/acpi.c b/sys/src/cmd/aux/acpi.c
index 9bd5e38fcf8168ca9b551d6f44eaef5e68844828..cca662ef3b50dd76363e5b0ce1c99c41b878c402 100644 (file)
--- a/sys/src/cmd/aux/acpi.c
+++ b/sys/src/cmd/aux/acpi.c
@@ -62,6 +62,8 @@ enum {
        Qbattery,
        Qcputemp,
        Qctl,
+
+       Qdisable = (uvlong)-1,
 };
 
 static void rootread(Req*);
@@ -354,7 +356,7 @@ fswalk1(Fid *fid, char *name, Qid *qid)
        }
 
        for(i = 1; i < nelem(dfile); i++){      /* i=1: 0 is root dir */
-               if(strcmp(dfile[i].name, name) == 0){
+               if(dfile[i].qid.path != Qdisable && strcmp(dfile[i].name, name) == 0){
                        *qid = dfile[i].qid;
                        fid->qid = *qid;
                        return nil;
@@ -424,12 +426,14 @@ rootread(Req *r)
 
        if(offset == 0) /* skip root */
                offset = 1;
-       for(; p+2 < ep; p += n){
+       for(; p+2 < ep && offset < nelem(dfile); p += n){
                if(fillstat(offset, &d, 0) < 0)
-                       break;
-               n = convD2M(&d, (uchar*)p, ep-p);
-               if(n <= BIT16SZ)
-                       break;
+                       n = 0;
+               else{
+                       n = convD2M(&d, (uchar*)p, ep-p);
+                       if(n <= BIT16SZ)
+                               break;
+               }
                offset++;
        }
        r->fid->aux = (void*)offset;
@@ -540,6 +544,11 @@ threadmain(int argc, char **argv)
        amlenum(amlroot, "_BIF", enumbat, nil);
        amlenum(amlroot, "_PSL", enumtmp, nil);
 
+       if(nbats < 1)
+               dfile[Qbattery].qid.path = Qdisable;
+       if(ntherms < 1)
+               dfile[Qcputemp].qid.path = Qdisable;
+
        threadpostmountsrv(&fs, srv, mtpt, MREPL);
        threadexits(nil);