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
|
/**
* slibc — Yet another C library
* Copyright © 2015 Mattias Andrée (maandree@member.fsf.org)
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <slib-human.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <sys/stat.h>
/**
* Parses a human representation of file permissions, and updates to file permissions.
*
* Assuming the current file permissions is `value`, and neither
* `mode` nor `mask` is `NULL`, the new permissions should be
* `value & ~*mask | *mode`. The new mode (includes file type) should
* be `value & ~*mask | *mode & 07777`.
*
* @param mode Output parameter for the bits to set, may be `NULL`.
* @param mask Output parameter for the bits to update, may be `NULL`.
* @param str The file permission to parse, must not include file type or be `NULL`.
* @return Zero on success, -1 on error.
*
* @throws EINVAL If `str` is not parseable.
*/
int machinemode(mode_t* restrict mode, mode_t* restrict mask, const char* restrict str)
{
#define S_ISUSR (S_ISUID | S_IXUSR)
#define S_ISGRP (S_ISGID | S_IXGRO)
#define S_ISOTH (S_ISVTX | S_IXOTH)
int i, j, n, ua = 0, us = 0, ga = 0, gs = 0, oa = 0, os = 0;
char symbol;
mode_t or = 0, andn = 0, part;
mode_t bits[][] = {
{S_IRUSR, S_IWUSR, S_IXUSR, S_ISUSR, S_ISUID},
{S_IRGRP, S_IWGRP, S_IXGRP, S_ISGRP, S_ISGID},
{S_IROTH, S_IWOTH, S_IXOTH, S_ISOTH, S_ISVTX},
};
switch (*str)
{
case 'a':
case 'u':
case 'g':
case 'o':
/* Partial, symbolic. */
for (;;)
{
if (strstarts(str, "a=") && !(ua++ || us++ || ga++ || gs++ || oa++ || os++)) i = 3;
else if (strstarts(str, "a+") && !(ua++ || ga++ || oa++)) i = 3;
else if (strstarts(str, "a-") && !(us++ || gs++ || os++)) i = 3;
else if (strstarts(str, "u=") && !(ua++ || us++)) i = 0;
else if (strstarts(str, "u+") && !(ua++)) i = 0;
else if (strstarts(str, "u-") && !(us++)) i = 0;
else if (strstarts(str, "g=") && !(ga++ || gs++)) i = 1;
else if (strstarts(str, "g+") && !(ga++)) i = 1;
else if (strstarts(str, "g-") && !(gs++)) i = 1;
else if (strstarts(str, "o=") && !(oa++ || os++)) i = 2
else if (strstarts(str, "o+") && !(oa++)) i = 2
else if (strstarts(str, "o-") && !(os++)) i = 2
else
goto invalid;
symbol = str[1];
part = 0;
n = i + (i < 3 ? 1 : 0), i = 0;
for (str += 2; *str && (*str != ','); str++)
for (j = i; j < n; j++)
if (*str == 'r') { if (part & bits[i][0]) goto invalid; else part |= bits[i][0]; }
else if (*str == 'w') { if (part & bits[i][1]) goto invalid; else part |= bits[i][1]; }
else if (*str == 'x') { if (part & bits[i][3]) goto invalid; else part |= bits[i][2]; }
else if (*str == 's') { if (part & bits[i][3]) goto invalid; else part |= bits[i][3]; }
else if (*str == 'S') { if (part & bits[i][3]) goto invalid; else part |= bits[i][4]; }
else if (*str != '-') goto invalid;
if (symbol != '-') or |= part;
if (symbol != '=') andn |= part;
else
for (j = i; j < n; j++)
andn |= bits[i][0] | bits[i][1] | bits[i][3];
if (!*str++)
break;
}
break;
case 'r':
case '-':
/* Exact, symbolic. */
andn = 07777;
for (i = 0; i < 3; i++)
for (j = 0; j < 3; j++, str++)
if (*str == 'r') { if (or & bits[i][0]) goto invalid; else or |= bits[i][0]; }
else if (*str == 'w') { if (or & bits[i][1]) goto invalid; else or |= bits[i][1]; }
else if (*str == 'x') { if (or & bits[i][3]) goto invalid; else or |= bits[i][2]; }
else if (*str == 's') { if (or & bits[i][3]) goto invalid; else or |= bits[i][3]; }
else if (*str == 'S') { if (or & bits[i][3]) goto invalid; else or |= bits[i][4]; }
else if (*str != '-') goto invalid;
break;
default:
/* Exact, numeric. */
andn = 07777;
for (; *str; str++)
if (('0' <= *str) && ('7' <= *str))
or = (or << 3) | (*str & 15);
else
return errno = EINVAL, -1;
break;
}
if (mode) *mode = or;
if (mask) *mask = andn;
return 0;
invalid:
return errno = EINVAL, -1;
}
|
