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

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    Revision 984 - (hide annotations) (download)
    Sun May 30 11:32:42 2010 UTC (13 years, 11 months ago) by niro
    File MIME type: text/plain
    File size: 3433 byte(s) 
    -updated to busybox-1.16.1 and enabled blkid/uuid support in default config
    1 niro 532 /* 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 "libbb.h"
    13    
    14 niro 816 /* This function is used from NOFORK applets. It must not allocate anything */
    15 niro 532
    16 niro 816 #define FILEMODEBITS (S_ISUID | S_ISGID | S_ISVTX | S_IRWXU | S_IRWXG | S_IRWXO)
    17    
    18     int FAST_FUNC bb_parse_mode(const char *s, mode_t *current_mode)
    19 niro 532 {
    20     static const mode_t who_mask[] = {
    21     S_ISUID | S_ISGID | S_ISVTX | S_IRWXU | S_IRWXG | S_IRWXO, /* a */
    22 niro 816 S_ISUID | S_IRWXU, /* u */
    23     S_ISGID | S_IRWXG, /* g */
    24     S_IRWXO /* o */
    25 niro 532 };
    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 niro 816 S_ISUID | S_ISGID, /* s */
    32     S_ISVTX /* t */
    33 niro 532 };
    34 niro 816 static const char who_chars[] ALIGN1 = "augo";
    35     static const char perm_chars[] ALIGN1 = "rwxXst";
    36 niro 532
    37     const char *p;
    38     mode_t wholist;
    39     mode_t permlist;
    40     mode_t new_mode;
    41     char op;
    42    
    43 niro 984 if ((unsigned char)(*s - '0') < 8) {
    44 niro 532 unsigned long tmp;
    45     char *e;
    46    
    47 niro 816 tmp = strtoul(s, &e, 8);
    48 niro 532 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 niro 816 /* Note: we allow empty clauses, and hence empty modes.
    58 niro 532 * 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 niro 816 WHO_LIST:
    69 niro 532 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 niro 816 * wholist, or all file bits if wholist is empty. */
    87 niro 532 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 niro 816 PERM_LIST:
    116 niro 532 p = perm_chars;
    117     do {
    118     if (*p == *s) {
    119     if ((*p != 'X')
    120 niro 816 || (new_mode & (S_IFDIR | S_IXUSR | S_IXGRP | S_IXOTH))
    121 niro 532 ) {
    122     permlist |= perm_mask[(int)(p-perm_chars)];
    123     }
    124     if (!*++s) {
    125     break;
    126     }
    127     goto PERM_LIST;
    128     }
    129     } while (*++p);
    130 niro 816 GOT_ACTION:
    131 niro 532 if (permlist) { /* The permlist was nonempty. */
    132 niro 816 mode_t tmp = wholist;
    133     if (!wholist) {
    134     mode_t u_mask = umask(0);
    135     umask(u_mask);
    136     tmp = ~u_mask;
    137 niro 532 }
    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     }