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 000000000..185957bc3
--- /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;
+}