blob: e8a8ed866435b1cece83473e19a7a3bfd20dade9 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
|
/*
* In place, rewrite name to compress multiple /, eliminate ., and process ..
*/
#define SEP(x) ((x)=='/' || (x) == 0)
char *
cleanname(char *name)
{
char *p, *q, *dotdot;
int rooted;
rooted = name[0] == '/';
/*
* invariants:
* p points at beginning of path element we're considering.
* q points just past the last path element we wrote (no slash).
* dotdot points just past the point where .. cannot backtrack
* any further (no slash).
*/
p = q = dotdot = name + rooted;
while (*p)
{
if (p[0] == '/') /* null element */
p++;
else if (p[0] == '.' && SEP(p[1]))
p += 1; /* don't count the separator in case it is nul */
else if (p[0] == '.' && p[1] == '.' && SEP(p[2]))
{
p += 2;
if (q > dotdot) { /* can backtrack */
while (--q > dotdot && *q != '/')
;
} else if (!rooted) { /* /.. is / but ./../ is .. */
if (q != name)
*q++ = '/';
*q++ = '.';
*q++ = '.';
dotdot = q;
}
}
else { /* real path element */
if (q != name + rooted)
*q++ = '/';
while ((*q = *p) != '/' && *q != 0)
p++, q++;
}
}
if (q == name) /* empty string is really ``.'' */
*q++ = '.';
*q = '\0';
return name;
}
|
