devdraw: fix topnwindows() panic when images are not windows (thanks aiju)

[plan9front.git] / sys / src / 9 / port / devsrv.c

diff --git a/sys/src/9/port/devsrv.c b/sys/src/9/port/devsrv.c
index 2c021289e97c571a59434928633abe8f46bb2132..193fa6c8bd274ebd57a31d3cf636d88ad78cbd35 100644 (file)
--- a/sys/src/9/port/devsrv.c
+++ b/sys/src/9/port/devsrv.c
@@ -21,8 +21,20 @@ static QLock srvlk;
 static Srv     *srv;
 static int     qidpath;
 
+static Srv*
+srvlookup(char *name, ulong qidpath)
+{
+       Srv *sp;
+
+       for(sp = srv; sp != nil; sp = sp->link) {
+               if(sp->path == qidpath || (name != nil && strcmp(sp->name, name) == 0))
+                       return sp;
+       }
+       return nil;
+}
+
 static int
-srvgen(Chan *c, char*, Dirtab*, int, int s, Dir *dp)
+srvgen(Chan *c, char *name, Dirtab*, int, int s, Dir *dp)
 {
        Srv *sp;
        Qid q;
@@ -33,14 +45,16 @@ srvgen(Chan *c, char*, Dirtab*, int, int s, Dir *dp)
        }
 
        qlock(&srvlk);
-       for(sp = srv; sp && s; sp = sp->link)
-               s--;
-
-       if(sp == 0) {
+       if(name != nil)
+               sp = srvlookup(name, -1);
+       else {
+               for(sp = srv; sp != nil && s > 0; sp = sp->link)
+                       s--;
+       }
+       if(sp == nil || (name != nil && (strlen(sp->name) >= sizeof(up->genbuf)))) {
                qunlock(&srvlk);
                return -1;
        }
-
        mkqid(&q, sp->path, 0, QTFILE);
        /* make sure name string continues to exist after we release lock */
        kstrcpy(up->genbuf, sp->name, sizeof up->genbuf);
@@ -67,16 +81,6 @@ srvwalk(Chan *c, Chan *nc, char **name, int nname)
        return devwalk(c, nc, name, nname, 0, 0, srvgen);
 }
 
-static Srv*
-srvlookup(char *name, ulong qidpath)
-{
-       Srv *sp;
-       for(sp = srv; sp; sp = sp->link)
-               if(sp->path == qidpath || (name && strcmp(sp->name, name) == 0))
-                       return sp;
-       return nil;
-}
-
 static int
 srvstat(Chan *c, uchar *db, int n)
 {
@@ -89,19 +93,25 @@ srvname(Chan *c)
        Srv *sp;
        char *s;
 
-       for(sp = srv; sp; sp = sp->link)
+       s = nil;
+       qlock(&srvlk);
+       for(sp = srv; sp != nil; sp = sp->link) {
                if(sp->chan == c){
-                       s = smalloc(3+strlen(sp->name)+1);
-                       sprint(s, "#s/%s", sp->name);
-                       return s;
+                       s = malloc(3+strlen(sp->name)+1);
+                       if(s != nil)
+                               sprint(s, "#s/%s", sp->name);
+                       break;
                }
-       return nil;
+       }
+       qunlock(&srvlk);
+       return s;
 }
 
 static Chan*
 srvopen(Chan *c, int omode)
 {
        Srv *sp;
+       Chan *nc;
 
        if(c->qid.type == QTDIR){
                if(omode & ORCLOSE)
@@ -120,64 +130,67 @@ srvopen(Chan *c, int omode)
        }
 
        sp = srvlookup(nil, c->qid.path);
-       if(sp == 0 || sp->chan == 0)
+       if(sp == nil || sp->chan == nil)
                error(Eshutdown);
 
        if(omode&OTRUNC)
-               error("srv file already exists");
+               error(Eexist);
        if(openmode(omode)!=sp->chan->mode && sp->chan->mode!=ORDWR)
                error(Eperm);
        devpermcheck(sp->owner, sp->perm, omode);
 
-       cclose(c);
-       incref(sp->chan);
+       nc = sp->chan;
+       incref(nc);
+
        qunlock(&srvlk);
        poperror();
-       return sp->chan;
+
+       cclose(c);
+       return nc;
 }
 
-static void
+static Chan*
 srvcreate(Chan *c, char *name, int omode, ulong perm)
 {
-       char *sname;
        Srv *sp;
 
        if(openmode(omode) != OWRITE)
                error(Eperm);
 
-       if(omode & OCEXEC)      /* can't happen */
-               panic("someone broke namec");
+       if(strlen(name) >= sizeof(up->genbuf))
+               error(Etoolong);
 
        sp = smalloc(sizeof *sp);
-       sname = smalloc(strlen(name)+1);
+       kstrdup(&sp->name, name);
+       kstrdup(&sp->owner, up->user);
 
        qlock(&srvlk);
        if(waserror()){
-               free(sp);
-               free(sname);
                qunlock(&srvlk);
+               free(sp->owner);
+               free(sp->name);
+               free(sp);
                nexterror();
        }
-       if(sp == nil || sname == nil)
-               error(Enomem);
-       if(srvlookup(name, -1))
+       if(srvlookup(name, -1) != nil)
                error(Eexist);
 
+       sp->perm = perm&0777;
        sp->path = qidpath++;
-       sp->link = srv;
-       strcpy(sname, name);
-       sp->name = sname;
-       c->qid.type = QTFILE;
+
        c->qid.path = sp->path;
+       c->qid.type = QTFILE;
+
+       sp->link = srv;
        srv = sp;
+
        qunlock(&srvlk);
        poperror();
 
-       kstrdup(&sp->owner, up->user);
-       sp->perm = perm&0777;
-
        c->flag |= COPEN;
        c->mode = OWRITE;
+
+       return c;
 }
 
 static void
@@ -194,13 +207,12 @@ srvremove(Chan *c)
                nexterror();
        }
        l = &srv;
-       for(sp = *l; sp; sp = sp->link) {
+       for(sp = *l; sp != nil; sp = *l) {
                if(sp->path == c->qid.path)
                        break;
-
                l = &sp->link;
        }
-       if(sp == 0)
+       if(sp == nil)
                error(Enonexist);
 
        /*
@@ -216,10 +228,12 @@ srvremove(Chan *c)
                error(Eperm);
 
        *l = sp->link;
+       sp->link = nil;
+
        qunlock(&srvlk);
        poperror();
 
-       if(sp->chan)
+       if(sp->chan != nil)
                cclose(sp->chan);
        free(sp->owner);
        free(sp->name);
@@ -230,43 +244,52 @@ static int
 srvwstat(Chan *c, uchar *dp, int n)
 {
        char *strs;
-       Dir d;
        Srv *sp;
+       Dir d;
 
        if(c->qid.type & QTDIR)
                error(Eperm);
 
-       strs = nil;
+       strs = smalloc(n);
+       if(waserror()){
+               free(strs);
+               nexterror();
+       }
+       n = convM2D(dp, n, &d, strs);
+       if(n == 0)
+               error(Eshortstat);
+
        qlock(&srvlk);
        if(waserror()){
                qunlock(&srvlk);
-               free(strs);
                nexterror();
        }
 
        sp = srvlookup(nil, c->qid.path);
-       if(sp == 0)
+       if(sp == nil)
                error(Enonexist);
 
        if(strcmp(sp->owner, up->user) != 0 && !iseve())
                error(Eperm);
 
-       strs = smalloc(n);
-       n = convM2D(dp, n, &d, strs);
-       if(n == 0)
-               error(Eshortstat);
-       if(d.mode != ~0UL)
-               sp->perm = d.mode & 0777;
-       if(d.uid && *d.uid)
-               kstrdup(&sp->owner, d.uid);
-       if(d.name && *d.name && strcmp(sp->name, d.name) != 0) {
+       if(d.name != nil && *d.name && strcmp(sp->name, d.name) != 0) {
                if(strchr(d.name, '/') != nil)
                        error(Ebadchar);
+               if(strlen(d.name) >= sizeof(up->genbuf))
+                       error(Etoolong);
                kstrdup(&sp->name, d.name);
        }
+       if(d.uid != nil && *d.uid)
+               kstrdup(&sp->owner, d.uid);
+       if(d.mode != ~0UL)
+               sp->perm = d.mode & 0777;
+
        qunlock(&srvlk);
+       poperror();
+
        free(strs);
        poperror();
+
        return n;
 }
 
@@ -302,7 +325,7 @@ srvwrite(Chan *c, void *va, long n, vlong)
        char buf[32];
 
        if(n >= sizeof buf)
-               error(Egreg);
+               error(Etoobig);
        memmove(buf, va, n);    /* so we can NUL-terminate */
        buf[n] = 0;
        fd = strtoul(buf, 0, 0);
@@ -320,13 +343,14 @@ srvwrite(Chan *c, void *va, long n, vlong)
        if(c1->qid.type & QTAUTH)
                error("cannot post auth file in srv");
        sp = srvlookup(nil, c->qid.path);
-       if(sp == 0)
+       if(sp == nil)
                error(Enonexist);
 
-       if(sp->chan)
+       if(sp->chan != nil)
                error(Ebadusefd);
 
        sp->chan = c1;
+
        qunlock(&srvlk);
        poperror();
        return n;
@@ -359,8 +383,9 @@ srvrenameuser(char *old, char *new)
        Srv *sp;
 
        qlock(&srvlk);
-       for(sp = srv; sp; sp = sp->link)
-               if(sp->owner!=nil && strcmp(old, sp->owner)==0)
+       for(sp = srv; sp != nil; sp = sp->link) {
+               if(sp->owner != nil && strcmp(old, sp->owner) == 0)
                        kstrdup(&sp->owner, new);
+       }
        qunlock(&srvlk);
 }