devproc: fix syscalltrace error handling, conistent use of nil for pointers

diff --git a/sys/src/9/port/devproc.c b/sys/src/9/port/devproc.c
index b5097b1abb46fb113ae08e943190dfa630606b38..483461868fde32bb93400fb861acd080f99c5c3e 100644 (file)
--- a/sys/src/9/port/devproc.c
+++ b/sys/src/9/port/devproc.c
@@ -171,7 +171,7 @@ profclock(Ureg *ur, Timer *)
 {
        Tos *tos;
 
-       if(up == 0 || up->state != Running)
+       if(up == nil || up->state != Running)
                return;
 
        /* user profiling clock */
@@ -688,7 +688,7 @@ prochaswaitq(void *x)
 
        c = (Chan *)x;
        p = proctab(SLOT(c->qid));
-       return p->pid != PID(c->qid) || p->waitq != 0;
+       return p->pid != PID(c->qid) || p->waitq != nil;
 }
 
 /*
@@ -764,11 +764,18 @@ procread(Chan *c, void *va, long n, vlong off)
                return n;
        case Qsyscall:
                eqlock(&p->debug);
-               if(p->syscalltrace)
+               if(waserror()){
+                       qunlock(&p->debug);
+                       nexterror();
+               }
+               if(p->pid != PID(c->qid))
+                       error(Eprocdied);
+               if(p->syscalltrace != nil)
                        n = readstr(offset, a, n, p->syscalltrace);
                else
                        n = 0;
                qunlock(&p->debug);
+               poperror();
                return n;
 
        case Qmem:
@@ -803,8 +810,8 @@ procread(Chan *c, void *va, long n, vlong off)
                if(s == nil || s->profile == nil)
                        error("profile is off");
                i = (s->top-s->base)>>LRESPROF;
-               i *= sizeof(*s->profile);
-               if(offset >= i)
+               i *= sizeof(s->profile[0]);
+               if(i < 0 || offset >= i)
                        return 0;
                if(offset+n > i)
                        n = i - offset;
@@ -863,7 +870,7 @@ procread(Chan *c, void *va, long n, vlong off)
                rptr = (uchar*)&p->fpsave;
                rsize = sizeof(FPsave);
        regread:
-               if(rptr == 0)
+               if(rptr == nil)
                        error(Enoreg);
                if(offset >= rsize)
                        return 0;
@@ -879,7 +886,7 @@ procread(Chan *c, void *va, long n, vlong off)
                        n = STATSIZE - offset;
 
                sps = p->psstate;
-               if(sps == 0)
+               if(sps == nil)
                        sps = statename[p->state];
 
                memset(statbuf, ' ', sizeof statbuf);
@@ -906,7 +913,7 @@ procread(Chan *c, void *va, long n, vlong off)
                j = 0;
                for(i = 0; i < NSEG; i++) {
                        sg = p->seg[i];
-                       if(sg == 0)
+                       if(sg == nil)
                                continue;
                        j += sprint(statbuf+j, "%-6s %c%c %8p %8p %4ld\n",
                                sname[sg->type&SG_TYPE],
@@ -933,7 +940,7 @@ procread(Chan *c, void *va, long n, vlong off)
                }
 
                lock(&p->exl);
-               while(p->waitq == 0 && p->pid == PID(c->qid)) {
+               while(p->waitq == nil && p->pid == PID(c->qid)) {
                        if(up == p && p->nchild == 0) {
                                unlock(&p->exl);
                                error(Enochild);
@@ -975,7 +982,7 @@ procread(Chan *c, void *va, long n, vlong off)
                        return 0;
                }
                mntscan(mw, p);
-               if(mw->mh == 0){
+               if(mw->mh == nil){
                        mw->cddone = 1;
                        i = snprint(a, n, "cd %s\n", p->dot->path->s);
                        qunlock(&p->debug);
@@ -1023,13 +1030,13 @@ mntscan(Mntwalk *mw, Proc *p)
        bestmid = ~0;
 
        last = 0;
-       if(mw->mh)
+       if(mw->mh != nil)
                last = mw->cm->mountid;
 
        for(i = 0; i < MNTHASH; i++) {
-               for(f = pg->mnthash[i]; f; f = f->hash) {
-                       for(t = f->mount; t; t = t->next) {
-                               if(mw->mh == 0 ||
+               for(f = pg->mnthash[i]; f != nil; f = f->hash) {
+                       for(t = f->mount; t != nil; t = t->next) {
+                               if(mw->mh == nil ||
                                  (t->mountid > last && t->mountid < bestmid)) {
                                        mw->cm = t;
                                        mw->mh = f;
@@ -1040,7 +1047,7 @@ mntscan(Mntwalk *mw, Proc *p)
                }
        }
        if(nxt == 0)
-               mw->mh = 0;
+               mw->mh = nil;
 
        runlock(&pg->ns);
 }
@@ -1106,7 +1113,7 @@ procwrite(Chan *c, void *va, long n, vlong off)
                        n = 0;
                else if(offset+n > sizeof(Ureg))
                        n = sizeof(Ureg) - offset;
-               if(p->dbgreg == 0)
+               if(p->dbgreg == nil)
                        error(Enoreg);
                setregisters(p->dbgreg, (char*)(p->dbgreg)+offset, va, n);
                break;
@@ -1218,7 +1225,7 @@ proctext(Chan *c, Proc *p)
        if(tc == nil)
                error(Eprocdied);
 
-       if(incref(tc) == 1 || (tc->flag&COPEN) == 0 || tc->mode!=OREAD) {
+       if(incref(tc) == 1 || (tc->flag&COPEN) == 0 || tc->mode != OREAD) {
                cclose(tc);
                error(Eprocdied);
        }
@@ -1239,7 +1246,7 @@ procstopwait(Proc *p, int ctl)
 {
        int pid;
 
-       if(p->pdbg)
+       if(p->pdbg != nil)
                error(Einuse);
        if(procstopped(p) || p->state == Broken)
                return;
@@ -1252,7 +1259,7 @@ procstopwait(Proc *p, int ctl)
        qunlock(&p->debug);
        up->psstate = "Stopwait";
        if(waserror()) {
-               p->pdbg = 0;
+               p->pdbg = nil;
                qlock(&p->debug);
                nexterror();
        }
@@ -1398,7 +1405,7 @@ procctlreq(Proc *p, char *va, int n)
                break;
        case CMprofile:
                s = p->seg[TSEG];
-               if(s == 0 || (s->type&SG_TYPE) != SG_TEXT)
+               if(s == nil || (s->type&SG_TYPE) != SG_TEXT)
                        error(Ebadctl);
                if(s->profile != nil)
                        free(s->profile);
@@ -1492,7 +1499,7 @@ procctlreq(Proc *p, char *va, int n)
                p->edf->flags |= Sendnotes;
                break;
        case CMadmit:
-               if(p->edf == 0)
+               if(p->edf == nil)
                        error("edf params");
                if(e = edfadmit(p))
                        error(e);
@@ -1503,12 +1510,12 @@ procctlreq(Proc *p, char *va, int n)
                p->edf->flags |= Extratime;
                break;
        case CMexpel:
-               if(p->edf)
+               if(p->edf != nil)
                        edfstop(p);
                break;
        case CMevent:
                pt = proctrace;
-               if(up->trace && pt)
+               if(up->trace && pt != nil)
                        pt(up, SUser, 0);
                break;
        }
@@ -1520,8 +1527,7 @@ procctlreq(Proc *p, char *va, int n)
 int
 procstopped(void *a)
 {
-       Proc *p = a;
-       return p->state == Stopped;
+       return ((Proc*)a)->state == Stopped;
 }
 
 ulong