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    Contents of /trunk/mkinitrd-magellan/busybox/libbb/parse_mode.c

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    Revision 532 - (show annotations) (download)
    Sat Sep 1 22:45:15 2007 UTC (16 years, 9 months ago) by niro
    File MIME type: text/plain
    File size: 3350 byte(s) 
    -import if magellan mkinitrd; it is a fork of redhats mkinitrd-5.0.8 with all magellan patches and features; deprecates magellan-src/mkinitrd
    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 tarball for details.
    8 */
    9
    10 /* http://www.opengroup.org/onlinepubs/007904975/utilities/chmod.html */
    11
    12 #include <stdlib.h>
    13 #include <assert.h>
    14 #include <sys/stat.h>
    15 #include "libbb.h"
    16
    17 #define FILEMODEBITS (S_ISUID | S_ISGID | S_ISVTX | S_IRWXU | S_IRWXG | S_IRWXO)
    18
    19 int bb_parse_mode(const char *s, mode_t *current_mode)
    20 {
    21 static const mode_t who_mask[] = {
    22 S_ISUID | S_ISGID | S_ISVTX | S_IRWXU | S_IRWXG | S_IRWXO, /* a */
    23 S_ISUID | S_IRWXU, /* u */
    24 S_ISGID | S_IRWXG, /* g */
    25 S_IRWXO /* o */
    26 };
    27
    28 static const mode_t perm_mask[] = {
    29 S_IRUSR | S_IRGRP | S_IROTH, /* r */
    30 S_IWUSR | S_IWGRP | S_IWOTH, /* w */
    31 S_IXUSR | S_IXGRP | S_IXOTH, /* x */
    32 S_IXUSR | S_IXGRP | S_IXOTH, /* X -- special -- see below */
    33 S_ISUID | S_ISGID, /* s */
    34 S_ISVTX /* t */
    35 };
    36
    37 static const char who_chars[] = "augo";
    38 static const char perm_chars[] = "rwxXst";
    39
    40 const char *p;
    41
    42 mode_t wholist;
    43 mode_t permlist;
    44 mode_t mask;
    45 mode_t new_mode;
    46 char op;
    47
    48 assert(s);
    49
    50 if (((unsigned int)(*s - '0')) < 8) {
    51 unsigned long tmp;
    52 char *e;
    53
    54 tmp = strtol(s, &e, 8);
    55 if (*e || (tmp > 07777U)) { /* Check range and trailing chars. */
    56 return 0;
    57 }
    58 *current_mode = tmp;
    59 return 1;
    60 }
    61
    62 mask = umask(0);
    63 umask(mask);
    64
    65 new_mode = *current_mode;
    66
    67 /* Note: We allow empty clauses, and hence empty modes.
    68 * We treat an empty mode as no change to perms. */
    69
    70 while (*s) { /* Process clauses. */
    71
    72 if (*s == ',') { /* We allow empty clauses. */
    73 ++s;
    74 continue;
    75 }
    76
    77 /* Get a wholist. */
    78 wholist = 0;
    79
    80 WHO_LIST:
    81 p = who_chars;
    82 do {
    83 if (*p == *s) {
    84 wholist |= who_mask[(int)(p-who_chars)];
    85 if (!*++s) {
    86 return 0;
    87 }
    88 goto WHO_LIST;
    89 }
    90 } while (*++p);
    91
    92 do { /* Process action list. */
    93 if ((*s != '+') && (*s != '-')) {
    94 if (*s != '=') {
    95 return 0;
    96 }
    97 /* Since op is '=', clear all bits corresponding to the
    98 * wholist, of all file bits if wholist is empty. */
    99 permlist = ~FILEMODEBITS;
    100 if (wholist) {
    101 permlist = ~wholist;
    102 }
    103 new_mode &= permlist;
    104 }
    105 op = *s++;
    106
    107 /* Check for permcopy. */
    108 p = who_chars + 1; /* Skip 'a' entry. */
    109 do {
    110 if (*p == *s) {
    111 int i = 0;
    112 permlist = who_mask[(int)(p-who_chars)]
    113 & (S_IRWXU | S_IRWXG | S_IRWXO)
    114 & new_mode;
    115 do {
    116 if (permlist & perm_mask[i]) {
    117 permlist |= perm_mask[i];
    118 }
    119 } while (++i < 3);
    120 ++s;
    121 goto GOT_ACTION;
    122 }
    123 } while (*++p);
    124
    125 /* It was not a permcopy, so get a permlist. */
    126 permlist = 0;
    127
    128 PERM_LIST:
    129 p = perm_chars;
    130 do {
    131 if (*p == *s) {
    132 if ((*p != 'X')
    133 || (new_mode & (S_IFDIR | S_IXUSR | S_IXGRP | S_IXOTH))
    134 ) {
    135 permlist |= perm_mask[(int)(p-perm_chars)];
    136 }
    137 if (!*++s) {
    138 break;
    139 }
    140 goto PERM_LIST;
    141 }
    142 } while (*++p);
    143
    144 GOT_ACTION:
    145 if (permlist) { /* The permlist was nonempty. */
    146 mode_t tmp = ~mask;
    147 if (wholist) {
    148 tmp = wholist;
    149 }
    150 permlist &= tmp;
    151
    152 if (op == '-') {
    153 new_mode &= ~permlist;
    154 } else {
    155 new_mode |= permlist;
    156 }
    157 }
    158 } while (*s && (*s != ','));
    159 }
    160
    161 *current_mode = new_mode;
    162
    163 return 1;
    164 }