/* 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 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 new_mode; char op; if (((unsigned int)(*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; }