diff options
Diffstat (limited to 'busybox/libbb/parse_mode.c')
| -rw-r--r-- | busybox/libbb/parse_mode.c | 177 |
1 files changed, 177 insertions, 0 deletions
diff --git a/busybox/libbb/parse_mode.c b/busybox/libbb/parse_mode.c new file mode 100644 index 0000000..185957b --- /dev/null +++ b/busybox/libbb/parse_mode.c @@ -0,0 +1,177 @@ +/* vi: set sw=4 ts=4: */ +/* + * parse_mode implementation for busybox + * + * Copyright (C) 2003 Manuel Novoa III <mjn3@codepoet.org> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + * + */ + +/* http://www.opengroup.org/onlinepubs/007904975/utilities/chmod.html */ + +#include <stdlib.h> +#include <assert.h> +#include <sys/stat.h> +#include "libbb.h" + +#define FILEMODEBITS (S_ISUID | S_ISGID | S_ISVTX | S_IRWXU | S_IRWXG | S_IRWXO) + +extern int 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[] = "augo"; + static const char perm_chars[] = "rwxXst"; + + const char *p; + + mode_t wholist; + mode_t permlist; + mode_t mask; + mode_t new_mode; + char op; + + assert(s); + + if (((unsigned int)(*s - '0')) < 8) { + unsigned long tmp; + char *e; + + tmp = strtol(s, &e, 8); + if (*e || (tmp > 07777U)) { /* Check range and trailing chars. */ + return 0; + } + *current_mode = tmp; + return 1; + } + + mask = umask(0); + umask(mask); + + 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, of 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 = ~mask; + if (wholist) { + tmp = wholist; + } + permlist &= tmp; + + if (op == '-') { + new_mode &= ~permlist; + } else { + new_mode |= permlist; + } + } + } while (*s && (*s != ',')); + } + + *current_mode = new_mode; + + return 1; +} |