source: MondoRescue/branches/3.0/mindi-busybox/libbb/parse_mode.c@ 3085

Last change on this file since 3085 was 2725, checked in by Bruno Cornec, 13 years ago
  • Update mindi-busybox to 1.18.3 to avoid problems with the tar command which is now failing on recent versions with busybox 1.7.3
File size: 3.4 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, mode_t *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 0;
50 }
51 *current_mode = tmp;
52 return 1;
53 }
54
55 new_mode = *current_mode;
56
57 /* Note: we allow empty clauses, and hence empty modes.
58 * We treat an empty mode as no change to perms. */
59
60 while (*s) { /* Process clauses. */
61 if (*s == ',') { /* We allow empty clauses. */
62 ++s;
63 continue;
64 }
65
66 /* Get a wholist. */
67 wholist = 0;
68 WHO_LIST:
69 p = who_chars;
70 do {
71 if (*p == *s) {
72 wholist |= who_mask[(int)(p-who_chars)];
73 if (!*++s) {
74 return 0;
75 }
76 goto WHO_LIST;
77 }
78 } while (*++p);
79
80 do { /* Process action list. */
81 if ((*s != '+') && (*s != '-')) {
82 if (*s != '=') {
83 return 0;
84 }
85 /* Since op is '=', clear all bits corresponding to the
86 * wholist, or all file bits if wholist is empty. */
87 permlist = ~FILEMODEBITS;
88 if (wholist) {
89 permlist = ~wholist;
90 }
91 new_mode &= permlist;
92 }
93 op = *s++;
94
95 /* Check for permcopy. */
96 p = who_chars + 1; /* Skip 'a' entry. */
97 do {
98 if (*p == *s) {
99 int i = 0;
100 permlist = who_mask[(int)(p-who_chars)]
101 & (S_IRWXU | S_IRWXG | S_IRWXO)
102 & new_mode;
103 do {
104 if (permlist & perm_mask[i]) {
105 permlist |= perm_mask[i];
106 }
107 } while (++i < 3);
108 ++s;
109 goto GOT_ACTION;
110 }
111 } while (*++p);
112
113 /* It was not a permcopy, so get a permlist. */
114 permlist = 0;
115 PERM_LIST:
116 p = perm_chars;
117 do {
118 if (*p == *s) {
119 if ((*p != 'X')
120 || (new_mode & (S_IFDIR | S_IXUSR | S_IXGRP | S_IXOTH))
121 ) {
122 permlist |= perm_mask[(int)(p-perm_chars)];
123 }
124 if (!*++s) {
125 break;
126 }
127 goto PERM_LIST;
128 }
129 } while (*++p);
130 GOT_ACTION:
131 if (permlist) { /* The permlist was nonempty. */
132 mode_t tmp = wholist;
133 if (!wholist) {
134 mode_t u_mask = umask(0);
135 umask(u_mask);
136 tmp = ~u_mask;
137 }
138 permlist &= tmp;
139 if (op == '-') {
140 new_mode &= ~permlist;
141 } else {
142 new_mode |= permlist;
143 }
144 }
145 } while (*s && (*s != ','));
146 }
147
148 *current_mode = new_mode;
149 return 1;
150}
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