| /* vi: set sw=4 ts=4: */ |
| /* |
| * parse_mode implementation for busybox |
| * |
| * Copyright (C) 2003 Manuel Novoa III <mjn3@codepoet.org> |
| * |
| * Licensed under GPLv2 or later, see file LICENSE in this tarball for details. |
| */ |
| |
| /* http://www.opengroup.org/onlinepubs/007904975/utilities/chmod.html */ |
| |
| #include "libbb.h" |
| |
| /* This function is used from NOFORK applets. It must not allocate anything */ |
| |
| #define FILEMODEBITS (S_ISUID | S_ISGID | S_ISVTX | S_IRWXU | S_IRWXG | S_IRWXO) |
| |
| int FAST_FUNC bb_parse_mode(const char *s, mode_t *current_mode) |
| { |
| static const mode_t who_mask[] = { |
| S_ISUID | S_ISGID | S_ISVTX | S_IRWXU | S_IRWXG | S_IRWXO, /* a */ |
| S_ISUID | S_IRWXU, /* u */ |
| S_ISGID | S_IRWXG, /* g */ |
| S_IRWXO /* o */ |
| }; |
| static const mode_t perm_mask[] = { |
| S_IRUSR | S_IRGRP | S_IROTH, /* r */ |
| S_IWUSR | S_IWGRP | S_IWOTH, /* w */ |
| S_IXUSR | S_IXGRP | S_IXOTH, /* x */ |
| S_IXUSR | S_IXGRP | S_IXOTH, /* X -- special -- see below */ |
| S_ISUID | S_ISGID, /* s */ |
| S_ISVTX /* t */ |
| }; |
| static const char who_chars[] ALIGN1 = "augo"; |
| static const char perm_chars[] ALIGN1 = "rwxXst"; |
| |
| const char *p; |
| mode_t wholist; |
| mode_t permlist; |
| mode_t new_mode; |
| char op; |
| |
| if ((unsigned char)(*s - '0') < 8) { |
| unsigned long tmp; |
| char *e; |
| |
| tmp = strtoul(s, &e, 8); |
| if (*e || (tmp > 07777U)) { /* Check range and trailing chars. */ |
| return 0; |
| } |
| *current_mode = tmp; |
| return 1; |
| } |
| |
| new_mode = *current_mode; |
| |
| /* Note: we allow empty clauses, and hence empty modes. |
| * We treat an empty mode as no change to perms. */ |
| |
| while (*s) { /* Process clauses. */ |
| if (*s == ',') { /* We allow empty clauses. */ |
| ++s; |
| continue; |
| } |
| |
| /* Get a wholist. */ |
| wholist = 0; |
| WHO_LIST: |
| p = who_chars; |
| do { |
| if (*p == *s) { |
| wholist |= who_mask[(int)(p-who_chars)]; |
| if (!*++s) { |
| return 0; |
| } |
| goto WHO_LIST; |
| } |
| } while (*++p); |
| |
| do { /* Process action list. */ |
| if ((*s != '+') && (*s != '-')) { |
| if (*s != '=') { |
| return 0; |
| } |
| /* Since op is '=', clear all bits corresponding to the |
| * wholist, or all file bits if wholist is empty. */ |
| permlist = ~FILEMODEBITS; |
| if (wholist) { |
| permlist = ~wholist; |
| } |
| new_mode &= permlist; |
| } |
| op = *s++; |
| |
| /* Check for permcopy. */ |
| p = who_chars + 1; /* Skip 'a' entry. */ |
| do { |
| if (*p == *s) { |
| int i = 0; |
| permlist = who_mask[(int)(p-who_chars)] |
| & (S_IRWXU | S_IRWXG | S_IRWXO) |
| & new_mode; |
| do { |
| if (permlist & perm_mask[i]) { |
| permlist |= perm_mask[i]; |
| } |
| } while (++i < 3); |
| ++s; |
| goto GOT_ACTION; |
| } |
| } while (*++p); |
| |
| /* It was not a permcopy, so get a permlist. */ |
| permlist = 0; |
| PERM_LIST: |
| p = perm_chars; |
| do { |
| if (*p == *s) { |
| if ((*p != 'X') |
| || (new_mode & (S_IFDIR | S_IXUSR | S_IXGRP | S_IXOTH)) |
| ) { |
| permlist |= perm_mask[(int)(p-perm_chars)]; |
| } |
| if (!*++s) { |
| break; |
| } |
| goto PERM_LIST; |
| } |
| } while (*++p); |
| GOT_ACTION: |
| if (permlist) { /* The permlist was nonempty. */ |
| mode_t tmp = wholist; |
| if (!wholist) { |
| mode_t u_mask = umask(0); |
| umask(u_mask); |
| tmp = ~u_mask; |
| } |
| permlist &= tmp; |
| if (op == '-') { |
| new_mode &= ~permlist; |
| } else { |
| new_mode |= permlist; |
| } |
| } |
| } while (*s && (*s != ',')); |
| } |
| |
| *current_mode = new_mode; |
| return 1; |
| } |