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-rw-r--r--examples/loadables/pathchk.c358
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diff --git a/examples/loadables/pathchk.c b/examples/loadables/pathchk.c
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+/* pathchk - check pathnames for validity and portability */
+
+/* Usage: pathchk [-p] path ...
+
+ For each PATH, print a message if any of these conditions are false:
+ * all existing leading directories in PATH have search (execute) permission
+ * strlen (PATH) <= PATH_MAX
+ * strlen (each_directory_in_PATH) <= NAME_MAX
+
+ Exit status:
+ 0 All PATH names passed all of the tests.
+ 1 An error occurred.
+
+ Options:
+ -p Instead of performing length checks on the
+ underlying filesystem, test the length of the
+ pathname and its components against the POSIX.1
+ minimum limits for portability, _POSIX_NAME_MAX
+ and _POSIX_PATH_MAX in 2.9.2. Also check that
+ the pathname contains no character not in the
+ portable filename character set. */
+
+/* See Makefile for compilation details. */
+
+#include <config.h>
+
+#include <sys/types.h>
+#include "posixstat.h"
+
+#if defined (HAVE_UNISTD_H)
+# include <unistd.h>
+#endif
+
+#if defined (HAVE_LIMITS_H)
+# include <limits.h>
+#endif
+
+#include "bashansi.h"
+
+#include <stdio.h>
+#include <errno.h>
+
+#include "builtins.h"
+#include "shell.h"
+#include "stdc.h"
+#include "bashgetopt.h"
+#include "maxpath.h"
+
+#if !defined (errno)
+extern int errno;
+#endif
+
+#if !defined (_POSIX_PATH_MAX)
+# define _POSIX_PATH_MAX 255
+#endif
+#if !defined (_POSIX_NAME_MAX)
+# define _POSIX_NAME_MAX 14
+#endif
+
+/* How do we get PATH_MAX? */
+#if defined (_POSIX_VERSION) && !defined (PATH_MAX)
+# define PATH_MAX_FOR(p) pathconf ((p), _PC_PATH_MAX)
+#endif
+
+/* How do we get NAME_MAX? */
+#if defined (_POSIX_VERSION) && !defined (NAME_MAX)
+# define NAME_MAX_FOR(p) pathconf ((p), _PC_NAME_MAX)
+#endif
+
+#if !defined (PATH_MAX_FOR)
+# define PATH_MAX_FOR(p) PATH_MAX
+#endif
+
+#if !defined (NAME_MAX_FOR)
+# define NAME_MAX_FOR(p) NAME_MAX
+#endif
+
+extern char *strerror ();
+
+static int validate_path ();
+
+pathchk_builtin (list)
+ WORD_LIST *list;
+{
+ int retval, pflag, opt;
+
+ reset_internal_getopt ();
+ while ((opt = internal_getopt (list, "p")) != -1)
+ {
+ switch (opt)
+ {
+ case 'p':
+ pflag = 1;
+ break;
+ default:
+ builtin_usage ();
+ return (EX_USAGE);
+ }
+ }
+ list = loptend;
+
+ if (list == 0)
+ {
+ builtin_usage ();
+ return (EX_USAGE);
+ }
+
+ for (retval = 0; list; list = list->next)
+ retval |= validate_path (list->word->word, pflag);
+
+ return (retval ? EXECUTION_FAILURE : EXECUTION_SUCCESS);
+}
+
+char *pathchk_doc[] = {
+ "Check each pathname argument for validity (i.e., it may be used to",
+ "create or access a file without casuing syntax errors) and portability",
+ "(i.e., no filename truncation will result). If the `-p' option is",
+ "supplied, more extensive portability checks are performed.",
+ (char *)NULL
+};
+
+/* The standard structure describing a builtin command. bash keeps an array
+ of these structures. */
+struct builtin pathchk_struct = {
+ "pathchk", /* builtin name */
+ pathchk_builtin, /* function implementing the builtin */
+ BUILTIN_ENABLED, /* initial flags for builtin */
+ pathchk_doc, /* array of long documentation strings. */
+ "pathchk [-p] pathname ...", /* usage synopsis */
+ 0 /* reserved for internal use */
+};
+
+/* The remainder of this file is stolen shamelessly from `pathchk.c' in
+ the sh-utils-1.12 distribution, by
+
+ David MacKenzie <djm@gnu.ai.mit.edu>
+ and Jim Meyering <meyering@cs.utexas.edu> */
+
+/* Each element is nonzero if the corresponding ASCII character is
+ in the POSIX portable character set, and zero if it is not.
+ In addition, the entry for `/' is nonzero to simplify checking. */
+static char const portable_chars[256] =
+{
+ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* 0-15 */
+ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* 16-31 */
+ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, /* 32-47 */
+ 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, /* 48-63 */
+ 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, /* 64-79 */
+ 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 1, /* 80-95 */
+ 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, /* 96-111 */
+ 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, /* 112-127 */
+ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
+};
+
+/* If PATH contains only portable characters, return 1, else 0. */
+
+static int
+portable_chars_only (path)
+ const char *path;
+{
+ const char *p;
+
+ for (p = path; *p; ++p)
+ if (portable_chars[(const unsigned char) *p] == 0)
+ {
+ builtin_error ("path `%s' contains nonportable character `%c'", path, *p);
+ return 0;
+ }
+ return 1;
+}
+
+/* On some systems, stat can return EINTR. */
+
+#ifndef EINTR
+# define SAFE_STAT(name, buf) stat (name, buf)
+#else
+# define SAFE_STAT(name, buf) safe_stat (name, buf)
+static inline int
+safe_stat (name, buf)
+ const char *name;
+ struct stat *buf;
+{
+ int ret;
+
+ do
+ ret = stat (name, buf);
+ while (ret < 0 && errno == EINTR);
+
+ return ret;
+}
+#endif
+
+/* Return 1 if PATH is a usable leading directory, 0 if not,
+ 2 if it doesn't exist. */
+
+static int
+dir_ok (path)
+ const char *path;
+{
+ struct stat stats;
+
+ if (SAFE_STAT (path, &stats))
+ return 2;
+
+ if (!S_ISDIR (stats.st_mode))
+ {
+ builtin_error ("`%s' is not a directory", path);
+ return 0;
+ }
+
+ /* Use access to test for search permission because
+ testing permission bits of st_mode can lose with new
+ access control mechanisms. Of course, access loses if you're
+ running setuid. */
+ if (access (path, X_OK) != 0)
+ {
+ if (errno == EACCES)
+ builtin_error ("directory `%s' is not searchable", path);
+ else
+ builtin_error ("%s: %s", path, strerror (errno));
+ return 0;
+ }
+
+ return 1;
+}
+
+static char *
+xstrdup (s)
+ char *s;
+{
+ return (savestring (s));
+}
+
+/* Make sure that
+ strlen (PATH) <= PATH_MAX
+ && strlen (each-existing-directory-in-PATH) <= NAME_MAX
+
+ If PORTABILITY is nonzero, compare against _POSIX_PATH_MAX and
+ _POSIX_NAME_MAX instead, and make sure that PATH contains no
+ characters not in the POSIX portable filename character set, which
+ consists of A-Z, a-z, 0-9, ., _, -.
+
+ Make sure that all leading directories along PATH that exist have
+ `x' permission.
+
+ Return 0 if all of these tests are successful, 1 if any fail. */
+
+static int
+validate_path (path, portability)
+ char *path;
+ int portability;
+{
+ int path_max;
+ int last_elem; /* Nonzero if checking last element of path. */
+ int exists; /* 2 if the path element exists. */
+ char *slash;
+ char *parent; /* Last existing leading directory so far. */
+
+ if (portability && !portable_chars_only (path))
+ return 1;
+
+ if (*path == '\0')
+ return 0;
+
+#ifdef lint
+ /* Suppress `used before initialized' warning. */
+ exists = 0;
+#endif
+
+ /* Figure out the parent of the first element in PATH. */
+ parent = xstrdup (*path == '/' ? "/" : ".");
+
+ slash = path;
+ last_elem = 0;
+ while (1)
+ {
+ int name_max;
+ int length; /* Length of partial path being checked. */
+ char *start; /* Start of path element being checked. */
+
+ /* Find the end of this element of the path.
+ Then chop off the rest of the path after this element. */
+ while (*slash == '/')
+ slash++;
+ start = slash;
+ slash = strchr (slash, '/');
+ if (slash != NULL)
+ *slash = '\0';
+ else
+ {
+ last_elem = 1;
+ slash = strchr (start, '\0');
+ }
+
+ if (!last_elem)
+ {
+ exists = dir_ok (path);
+ if (dir_ok == 0)
+ {
+ free (parent);
+ return 1;
+ }
+ }
+
+ length = slash - start;
+ /* Since we know that `parent' is a directory, it's ok to call
+ pathconf with it as the argument. (If `parent' isn't a directory
+ or doesn't exist, the behavior of pathconf is undefined.)
+ But if `parent' is a directory and is on a remote file system,
+ it's likely that pathconf can't give us a reasonable value
+ and will return -1. (NFS and tempfs are not POSIX . . .)
+ In that case, we have no choice but to assume the pessimal
+ POSIX minimums. */
+ name_max = portability ? _POSIX_NAME_MAX : NAME_MAX_FOR (parent);
+ if (name_max < 0)
+ name_max = _POSIX_NAME_MAX;
+ if (length > name_max)
+ {
+ builtin_error ("name `%s' has length %d; exceeds limit of %d",
+ start, length, name_max);
+ free (parent);
+ return 1;
+ }
+
+ if (last_elem)
+ break;
+
+ if (exists == 1)
+ {
+ free (parent);
+ parent = xstrdup (path);
+ }
+
+ *slash++ = '/';
+ }
+
+ /* `parent' is now the last existing leading directory in the whole path,
+ so it's ok to call pathconf with it as the argument. */
+ path_max = portability ? _POSIX_PATH_MAX : PATH_MAX_FOR (parent);
+ if (path_max < 0)
+ path_max = _POSIX_PATH_MAX;
+ free (parent);
+ if (strlen (path) > path_max)
+ {
+ builtin_error ("path `%s' has length %d; exceeds limit of %d",
+ path, strlen (path), path_max);
+ return 1;
+ }
+
+ return 0;
+}
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