source: MondoRescue/branches/3.3/mindi-busybox/libbb/parse_mode.c@ 3621

Last change on this file since 3621 was 3621, checked in by Bruno Cornec, 7 years ago

New 3?3 banch for incorporation of latest busybox 1.25. Changing minor version to handle potential incompatibilities.
File size: 3.3 KB
Line 
1/* vi: set sw=4 ts=4: */
2/*
3 * parse_mode implementation for busybox
4 *
5 * Copyright (C) 2003 Manuel Novoa III <mjn3@codepoet.org>
6 *
7 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
8 */
9
10/* http://www.opengroup.org/onlinepubs/007904975/utilities/chmod.html */
11
12#include "libbb.h"
13
14/* This function is used from NOFORK applets. It must not allocate anything */
15
16#define FILEMODEBITS (S_ISUID | S_ISGID | S_ISVTX | S_IRWXU | S_IRWXG | S_IRWXO)
17
18int FAST_FUNC bb_parse_mode(const char *s, unsigned current_mode)
19{
20 static const mode_t who_mask[] = {
21 S_ISUID | S_ISGID | S_ISVTX | S_IRWXU | S_IRWXG | S_IRWXO, /* a */
22 S_ISUID | S_IRWXU, /* u */
23 S_ISGID | S_IRWXG, /* g */
24 S_IRWXO /* o */
25 };
26 static const mode_t perm_mask[] = {
27 S_IRUSR | S_IRGRP | S_IROTH, /* r */
28 S_IWUSR | S_IWGRP | S_IWOTH, /* w */
29 S_IXUSR | S_IXGRP | S_IXOTH, /* x */
30 S_IXUSR | S_IXGRP | S_IXOTH, /* X -- special -- see below */
31 S_ISUID | S_ISGID, /* s */
32 S_ISVTX /* t */
33 };
34 static const char who_chars[] ALIGN1 = "augo";
35 static const char perm_chars[] ALIGN1 = "rwxXst";
36
37 const char *p;
38 mode_t wholist;
39 mode_t permlist;
40 mode_t new_mode;
41 char op;
42
43 if ((unsigned char)(*s - '0') < 8) {
44 unsigned long tmp;
45 char *e;
46
47 tmp = strtoul(s, &e, 8);
48 if (*e || (tmp > 07777U)) { /* Check range and trailing chars. */
49 return -1;
50 }
51 return tmp;
52 }
53
54 new_mode = current_mode;
55
56 /* Note: we allow empty clauses, and hence empty modes.
57 * We treat an empty mode as no change to perms. */
58
59 while (*s) { /* Process clauses. */
60 if (*s == ',') { /* We allow empty clauses. */
61 ++s;
62 continue;
63 }
64
65 /* Get a wholist. */
66 wholist = 0;
67 WHO_LIST:
68 p = who_chars;
69 do {
70 if (*p == *s) {
71 wholist |= who_mask[(int)(p-who_chars)];
72 if (!*++s) {
73 return -1;
74 }
75 goto WHO_LIST;
76 }
77 } while (*++p);
78
79 do { /* Process action list. */
80 if ((*s != '+') && (*s != '-')) {
81 if (*s != '=') {
82 return -1;
83 }
84 /* Since op is '=', clear all bits corresponding to the
85 * wholist, or all file bits if wholist is empty. */
86 permlist = ~FILEMODEBITS;
87 if (wholist) {
88 permlist = ~wholist;
89 }
90 new_mode &= permlist;
91 }
92 op = *s++;
93
94 /* Check for permcopy. */
95 p = who_chars + 1; /* Skip 'a' entry. */
96 do {
97 if (*p == *s) {
98 int i = 0;
99 permlist = who_mask[(int)(p-who_chars)]
100 & (S_IRWXU | S_IRWXG | S_IRWXO)
101 & new_mode;
102 do {
103 if (permlist & perm_mask[i]) {
104 permlist |= perm_mask[i];
105 }
106 } while (++i < 3);
107 ++s;
108 goto GOT_ACTION;
109 }
110 } while (*++p);
111
112 /* It was not a permcopy, so get a permlist. */
113 permlist = 0;
114 PERM_LIST:
115 p = perm_chars;
116 do {
117 if (*p == *s) {
118 if ((*p != 'X')
119 || (new_mode & (S_IFDIR | S_IXUSR | S_IXGRP | S_IXOTH))
120 ) {
121 permlist |= perm_mask[(int)(p-perm_chars)];
122 }
123 if (!*++s) {
124 break;
125 }
126 goto PERM_LIST;
127 }
128 } while (*++p);
129 GOT_ACTION:
130 if (permlist) { /* The permlist was nonempty. */
131 mode_t tmp = wholist;
132 if (!wholist) {
133 mode_t u_mask = umask(0);
134 umask(u_mask);
135 tmp = ~u_mask;
136 }
137 permlist &= tmp;
138 if (op == '-') {
139 new_mode &= ~permlist;
140 } else {
141 new_mode |= permlist;
142 }
143 }
144 } while (*s && (*s != ','));
145 }
146
147 return new_mode;
148}
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