inferno-os/liblogfs/create.c

#include "logfsos.h"
#include "logfs.h"
#include "local.h"

char *
logfsservercreate(LogfsServer *server, u32int fid, char *name, u32int perm, uchar mode, Qid *qid)
{
	Fid *f;
	char *uid;
	ulong newpath;
	char *errmsg;
	Entry *e, *xe, *pe;
	Path *pp;
	LogMessage s;

	if(server->trace > 1)
		print("logfsservercreate(%ud, %s, 0%uo, %.2ux)\n", fid, name, perm, mode);
	f = logfsfidmapfindentry(server->fidmap, fid);
	if(f == nil)
		return logfsebadfid;
	if(f->openmode >= 0)
		return logfsefidopen;
	pe = f->entry;
	if((pe->qid.type & QTDIR) == 0)
		return Enotdir;
	if((perm & DMDIR) != 0 && ((mode & OTRUNC) != 0 || (mode &  3) != OREAD))
		return Eperm;
	if(!logfsuserpermcheck(server, pe, f, DMWRITE))
		return Eperm;
	/*
	 * illegal names
	 */
	if(strcmp(name, ".") == 0 || strcmp(name, "..") == 0)
		return Eperm;
	for(xe = pe->u.dir.list; xe; xe = xe->next)
		if(strcmp(xe->name, name) == 0)
			return Eexist;
	newpath = ++server->path;
	while(logfspathmapfindentry(server->pathmap, newpath))
		newpath++;	/* shouldn't happen */
	uid = logfsisfindidfromname(server->is, f->uname);
	errmsg = logfsentrynew(server, 1, newpath,
		pe, name, uid, f->entry->gid, logfsnow(), uid, perm, 0, 0, &e);
	if(errmsg)
		return errmsg;
	errmsg = logfspathmapnewentry(server->pathmap, newpath, e, &pp);
	/* pp is guaranteed to be non-null */
	if(errmsg) {
		logfsfreemem(e);
		return errmsg;
	}
	s.type = LogfsLogTcreate;
	s.path = e->parent->qid.path;	
	s.u.create.perm = e->perm;
	s.u.create.newpath = e->qid.path;
	s.u.create.mtime = e->mtime;
	/* TODO - check with forsyth whether cvers is needed in dirs */
	s.u.create.cvers = (e->qid.type & QTDIR) ? 0 : e->u.file.cvers;
	s.u.create.name = e->name;
	s.u.create.uid = e->uid;
	s.u.create.gid = e->gid;
	errmsg = logfslog(server, 1, &s);
	if(errmsg) {
		logfsfreemem(e);
		logfspathmapdeleteentry(server->pathmap, newpath);
		return errmsg;
	}
	server->path = newpath;
	e->inuse++;
	e->qid.vers++;
	e->next = pe->u.dir.list;
	pe->u.dir.list = e;
	f->openmode = mode;
	/*
	 * TODO why does forsyth increment inuse for dir? - we're moving the fid onto the new file
	 * so a decrement seems better
	 */
	logfsentryclunk(pe);
	f->entry = e;
	*qid = e->qid;
	return nil;
}