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
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
|
#include "common.h"
/* expand a path relative to some `.' */
extern String *
abspath(char *path, char *dot, String *to)
{
if (*path == '/') {
to = s_append(to, path);
} else {
to = s_append(to, dot);
to = s_append(to, "/");
to = s_append(to, path);
}
return to;
}
/* return a pointer to the base component of a pathname */
extern char *
basename(char *path)
{
char *cp;
cp = strrchr(path, '/');
return cp==0 ? path : cp+1;
}
/* append a sub-expression match onto a String */
extern void
append_match(Resub *subexp, String *sp, int se)
{
char *cp, *ep;
cp = subexp[se].s.sp;
ep = subexp[se].e.ep;
for (; cp < ep; cp++)
s_putc(sp, *cp);
s_terminate(sp);
}
/*
* check for shell characters in a String
*/
static char *illegalchars = "\r\n";
extern int
shellchars(char *cp)
{
char *sp;
for(sp=illegalchars; *sp; sp++)
if(strchr(cp, *sp))
return 1;
return 0;
}
static char *specialchars = " ()<>{};=\\'`^&|";
static char *escape = "%%";
int
hexchar(int x)
{
x &= 0xf;
if(x < 10)
return '0' + x;
else
return 'A' + x - 10;
}
/*
* rewrite a string to escape shell characters
*/
extern String*
escapespecial(String *s)
{
String *ns;
char *sp;
for(sp = specialchars; *sp; sp++)
if(strchr(s_to_c(s), *sp))
break;
if(*sp == 0)
return s;
ns = s_new();
for(sp = s_to_c(s); *sp; sp++){
if(strchr(specialchars, *sp)){
s_append(ns, escape);
s_putc(ns, hexchar(*sp>>4));
s_putc(ns, hexchar(*sp));
} else
s_putc(ns, *sp);
}
s_terminate(ns);
s_free(s);
return ns;
}
uint
hex2uint(char x)
{
if(x >= '0' && x <= '9')
return x - '0';
if(x >= 'A' && x <= 'F')
return (x - 'A') + 10;
if(x >= 'a' && x <= 'f')
return (x - 'a') + 10;
return -512;
}
/*
* rewrite a string to remove shell characters escapes
*/
extern String*
unescapespecial(String *s)
{
String *ns;
char *sp;
uint c, n;
if(strstr(s_to_c(s), escape) == 0)
return s;
n = strlen(escape);
ns = s_new();
for(sp = s_to_c(s); *sp; sp++){
if(strncmp(sp, escape, n) == 0){
c = (hex2uint(sp[n])<<4) + hex2uint(sp[n+1]);
if(c < 0)
s_putc(ns, *sp);
else {
s_putc(ns, c);
sp += n+2-1;
}
} else
s_putc(ns, *sp);
}
s_terminate(ns);
s_free(s);
return ns;
}
int
returnable(char *path)
{
return strcmp(path, "/dev/null") != 0;
}
|