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#include <u.h>
2 
#include <libc.h>
3 
#include <fcall.h>
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#include <thread.h>
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#include <9p.h>
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#include <mp.h>
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#include <libsec.h>
8 
 
9 
static void
10 
usage(void)
11 
{
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	fprint(2, "mntgen [-s srvname] [mtpt]\n");
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	exits("usage");
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}
15 
 
16 
ulong time0;
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18 
typedef struct Tab Tab;
19 
struct Tab
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{
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	char *name;
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	vlong qid;
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	ulong time;
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	int ref;
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};
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27 
Tab *tab;
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int ntab;
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int mtab;
30 
 
31 
static Tab*
32 
findtab(vlong path)
33 
{
34 
	int i;
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36 
	for(i=0; i<ntab; i++)
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		if(tab[i].qid == path)
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			return &tab[i];
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	return nil;
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}
41 
 
42 
static vlong
43 
hash(char *name)
44 
{
45 
	vlong digest[MD5dlen / sizeof(vlong) + 1];
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	md5((uchar *)name, strlen(name), (uchar *)digest, nil);
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	return digest[0] & ((1ULL<<48)-1);
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}
49 
 
50 
static void
51 
fsopen(Req *r)
52 
{
53 
	if(r->ifcall.mode != OREAD)
54 
		respond(r, "permission denied");
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	else
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		respond(r, nil);
57 
}
58 
 
59 
static int
60 
dirgen(int i, Dir *d, void*)
61 
{
62 
	if(i >= ntab)
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		return -1;
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	memset(d, 0, sizeof *d);
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	d->qid.type = QTDIR;
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	d->uid = estrdup9p("sys");
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	d->gid = estrdup9p("sys");
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	d->mode = DMDIR|0555;
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	d->length = 0;
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	if(i == -1){
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		d->name = estrdup9p("/");
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		d->atime = d->mtime = time0;
73 
	}else{
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		d->qid.path = tab[i].qid;
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		d->name = estrdup9p(tab[i].name);
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		d->atime = d->mtime = tab[i].time;
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	}
78 
	return 0;
79 
}
80 
 
81 
static void
82 
fsread(Req *r)
83 
{
84 
	if(r->fid->qid.path == 0)
85 
		dirread9p(r, dirgen, nil);
86 
	else
87 
		r->ofcall.count = 0;
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	respond(r, nil);
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}
90 
 
91 
static void
92 
fsstat(Req *r)
93 
{
94 
	Tab *t;
95 
	vlong qid;
96 
 
97 
	qid = r->fid->qid.path;
98 
	if(qid == 0)
99 
		dirgen(-1, &r->d, nil);
100 
	else{
101 
		if((t = findtab(qid)) == nil){
102 
			respond(r, "path not found (???)");
103 
			return;
104 
		}
105 
		dirgen(t-tab, &r->d, nil);
106 
	}
107 
	respond(r, nil);
108 
}
109 
 
110 
static char*
111 
fswalk1(Fid *fid, char *name, void*)
112 
{
113 
	int i;
114 
	Tab *t;
115 
	vlong h;
116 
 
117 
	if(fid->qid.path != 0){
118 
		/* nothing in child directory */
119 
		if(strcmp(name, "..") == 0){
120 
			if((t = findtab(fid->qid.path)) != nil)
121 
				t->ref--;
122 
			fid->qid.path = 0;
123 
			return nil;
124 
		}
125 
		return "path not found";
126 
	}
127 
	/* root */
128 
	if(strcmp(name, "..") == 0)
129 
		return nil;
130 
	for(i=0; i<ntab; i++)
131 
		if(strcmp(tab[i].name, name) == 0){
132 
			tab[i].ref++;
133 
			fid->qid.path = tab[i].qid;
134 
			return nil;
135 
		}
136 
	h = hash(name);
137 
	if(findtab(h) != nil)
138 
		return "hash collision";
139 
 
140 
	/* create it */
141 
	if(ntab == mtab){
142 
		if(mtab == 0)
143 
			mtab = 16;
144 
		else
145 
			mtab *= 2;
146 
		tab = erealloc9p(tab, sizeof(tab[0])*mtab);
147 
	}
148 
	tab[ntab].qid = h;
149 
	fid->qid.path = tab[ntab].qid;
150 
	tab[ntab].name = estrdup9p(name);
151 
	tab[ntab].time = time(0);
152 
	tab[ntab].ref = 1;
153 
	ntab++;
154 
 
155 
	return nil;
156 
}
157 
 
158 
static char*
159 
fsclone(Fid *fid, Fid*, void*)
160 
{
161 
	Tab *t;
162 
 
163 
	if((t = findtab(fid->qid.path)) != nil)
164 
		t->ref++;
165 
	return nil;
166 
}
167 
 
168 
static void
169 
fswalk(Req *r)
170 
{
171 
	walkandclone(r, fswalk1, fsclone, nil);
172 
}
173 
 
174 
static void
175 
fsclunk(Fid *fid)
176 
{
177 
	Tab *t;
178 
	vlong qid;
179 
 
180 
	qid = fid->qid.path;
181 
	if(qid == 0)
182 
		return;
183 
	if((t = findtab(qid)) == nil){
184 
		fprint(2, "warning: cannot find %llux\n", qid);
185 
		return;
186 
	}
187 
	if(--t->ref == 0){
188 
		free(t->name);
189 
		tab[t-tab] = tab[--ntab];
190 
	}else if(t->ref < 0)
191 
		fprint(2, "warning: negative ref count for %s\n", t->name);
192 
}
193 
 
194 
static void
195 
fsattach(Req *r)
196 
{
197 
	char *spec;
198 
 
199 
	spec = r->ifcall.aname;
200 
	if(spec && spec[0]){
201 
		respond(r, "invalid attach specifier");
202 
		return;
203 
	}
204 
 
205 
	r->ofcall.qid = (Qid){0, 0, QTDIR};
206 
	r->fid->qid = r->ofcall.qid;
207 
	respond(r, nil);
208 
}
209 
 
210 
Srv fs=
211 
{
212 
.attach=	fsattach,
213 
.open=	fsopen,
214 
.read=	fsread,
215 
.stat=	fsstat,
216 
.walk=	fswalk,
217 
.destroyfid=	fsclunk
218 
};
219 
 
220 
void
221 
main(int argc, char **argv)
222 
{
223 
	char *service;
224 
 
225 
	time0 = time(0);
226 
	service = nil;
227 
	ARGBEGIN{
228 
	case 'D':
229 
		chatty9p++;
230 
		break;
231 
	case 's':
232 
		service = EARGF(usage());
233 
		break;
234 
	default:
235 
		usage();
236 
	}ARGEND
237 
 
238 
	if(argc > 1)
239 
		usage();
240 
	postmountsrv(&fs, service, argc ? argv[0] : "/n", MAFTER);
241 
	exits(nil);
242 
}