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Diffstat (limited to 'src/pathchk.c')
| -rw-r--r-- | src/pathchk.c | 419 |
1 files changed, 419 insertions, 0 deletions
diff --git a/src/pathchk.c b/src/pathchk.c new file mode 100644 index 0000000..9614294 --- /dev/null +++ b/src/pathchk.c @@ -0,0 +1,419 @@ +/* pathchk -- check whether file names are valid or portable + Copyright (C) 1991-2023 Free Software Foundation, Inc. + + 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 3 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, see <https://www.gnu.org/licenses/>. */ + +#include <config.h> +#include <stdio.h> +#include <getopt.h> +#include <sys/types.h> +#include <wchar.h> + +#include "system.h" +#include "quote.h" + +/* The official name of this program (e.g., no 'g' prefix). */ +#define PROGRAM_NAME "pathchk" + +#define AUTHORS \ + proper_name ("Paul Eggert"), \ + proper_name ("David MacKenzie"), \ + proper_name ("Jim Meyering") + +#ifndef _POSIX_PATH_MAX +# define _POSIX_PATH_MAX 256 +#endif +#ifndef _POSIX_NAME_MAX +# define _POSIX_NAME_MAX 14 +#endif + +#ifdef _XOPEN_NAME_MAX +# define NAME_MAX_MINIMUM _XOPEN_NAME_MAX +#else +# define NAME_MAX_MINIMUM _POSIX_NAME_MAX +#endif +#ifdef _XOPEN_PATH_MAX +# define PATH_MAX_MINIMUM _XOPEN_PATH_MAX +#else +# define PATH_MAX_MINIMUM _POSIX_PATH_MAX +#endif + +#if ! (HAVE_PATHCONF && defined _PC_NAME_MAX && defined _PC_PATH_MAX) +# ifndef _PC_NAME_MAX +# define _PC_NAME_MAX 0 +# define _PC_PATH_MAX 1 +# endif +# ifndef pathconf +# define pathconf(file, flag) \ + (flag == _PC_NAME_MAX ? NAME_MAX_MINIMUM : PATH_MAX_MINIMUM) +# endif +#endif + +static bool validate_file_name (char *, bool, bool); + +/* For long options that have no equivalent short option, use a + non-character as a pseudo short option, starting with CHAR_MAX + 1. */ +enum +{ + PORTABILITY_OPTION = CHAR_MAX + 1 +}; + +static struct option const longopts[] = +{ + {"portability", no_argument, nullptr, PORTABILITY_OPTION}, + {GETOPT_HELP_OPTION_DECL}, + {GETOPT_VERSION_OPTION_DECL}, + {nullptr, 0, nullptr, 0} +}; + +void +usage (int status) +{ + if (status != EXIT_SUCCESS) + emit_try_help (); + else + { + printf (_("Usage: %s [OPTION]... NAME...\n"), program_name); + fputs (_("\ +Diagnose invalid or non-portable file names.\n\ +\n\ + -p check for most POSIX systems\n\ + -P check for empty names and leading \"-\"\n\ + --portability check for all POSIX systems (equivalent to -p -P)\n\ +"), stdout); + fputs (HELP_OPTION_DESCRIPTION, stdout); + fputs (VERSION_OPTION_DESCRIPTION, stdout); + emit_ancillary_info (PROGRAM_NAME); + } + exit (status); +} + +int +main (int argc, char **argv) +{ + bool ok = true; + bool check_basic_portability = false; + bool check_extra_portability = false; + int optc; + + initialize_main (&argc, &argv); + set_program_name (argv[0]); + setlocale (LC_ALL, ""); + bindtextdomain (PACKAGE, LOCALEDIR); + textdomain (PACKAGE); + + atexit (close_stdout); + + while ((optc = getopt_long (argc, argv, "+pP", longopts, nullptr)) != -1) + { + switch (optc) + { + case PORTABILITY_OPTION: + check_basic_portability = true; + check_extra_portability = true; + break; + + case 'p': + check_basic_portability = true; + break; + + case 'P': + check_extra_portability = true; + break; + + case_GETOPT_HELP_CHAR; + + case_GETOPT_VERSION_CHAR (PROGRAM_NAME, AUTHORS); + + default: + usage (EXIT_FAILURE); + } + } + + if (optind == argc) + { + error (0, 0, _("missing operand")); + usage (EXIT_FAILURE); + } + + for (; optind < argc; ++optind) + ok &= validate_file_name (argv[optind], + check_basic_portability, check_extra_portability); + + return ok ? EXIT_SUCCESS : EXIT_FAILURE; +} + +/* If FILE contains a component with a leading "-", report an error + and return false; otherwise, return true. */ + +static bool +no_leading_hyphen (char const *file) +{ + char const *p; + + for (p = file; (p = strchr (p, '-')); p++) + if (p == file || p[-1] == '/') + { + error (0, 0, _("leading '-' in a component of file name %s"), + quoteaf (file)); + return false; + } + + return true; +} + +/* If FILE (of length FILELEN) contains only portable characters, + return true, else report an error and return false. */ + +static bool +portable_chars_only (char const *file, size_t filelen) +{ + size_t validlen = strspn (file, + ("/" + "ABCDEFGHIJKLMNOPQRSTUVWXYZ" + "abcdefghijklmnopqrstuvwxyz" + "0123456789._-")); + char const *invalid = file + validlen; + + if (*invalid) + { + mbstate_t mbstate = { 0, }; + size_t charlen = mbrlen (invalid, filelen - validlen, &mbstate); + error (0, 0, + _("non-portable character %s in file name %s"), + quotearg_n_style_mem (1, locale_quoting_style, invalid, + (charlen <= MB_LEN_MAX ? charlen : 1)), + quoteaf_n (0, file)); + return false; + } + + return true; +} + +/* Return the address of the start of the next file name component in F. */ + +ATTRIBUTE_PURE +static char * +component_start (char *f) +{ + while (*f == '/') + f++; + return f; +} + +/* Return the size of the file name component F. F must be nonempty. */ + +ATTRIBUTE_PURE +static size_t +component_len (char const *f) +{ + size_t len; + for (len = 1; f[len] != '/' && f[len]; len++) + continue; + return len; +} + +/* Make sure that + strlen (FILE) <= PATH_MAX + && strlen (each-existing-directory-in-FILE) <= NAME_MAX + + If CHECK_BASIC_PORTABILITY is true, compare against _POSIX_PATH_MAX and + _POSIX_NAME_MAX instead, and make sure that FILE contains no + characters not in the POSIX portable filename character set, which + consists of A-Z, a-z, 0-9, ., _, - (plus / for separators). + + If CHECK_BASIC_PORTABILITY is false, make sure that all leading directories + along FILE that exist are searchable. + + If CHECK_EXTRA_PORTABILITY is true, check that file name components do not + begin with "-". + + If either CHECK_BASIC_PORTABILITY or CHECK_EXTRA_PORTABILITY is true, + check that the file name is not empty. + + Return true if all of these tests are successful, false if any fail. */ + +static bool +validate_file_name (char *file, bool check_basic_portability, + bool check_extra_portability) +{ + idx_t filelen = strlen (file); + + /* Start of file name component being checked. */ + char *start; + + /* True if component lengths need to be checked. */ + bool check_component_lengths; + + /* True if the file is known to exist. */ + bool file_exists = false; + + if (check_extra_portability && ! no_leading_hyphen (file)) + return false; + + if ((check_basic_portability || check_extra_portability) + && filelen == 0) + { + /* Fail, since empty names are not portable. As of + 2005-01-06 POSIX does not address whether "pathchk -p ''" + should (or is allowed to) fail, so this is not a + conformance violation. */ + error (0, 0, _("empty file name")); + return false; + } + + if (check_basic_portability) + { + if (! portable_chars_only (file, filelen)) + return false; + } + else + { + /* Check whether a file name component is in a directory that + is not searchable, or has some other serious problem. + POSIX does not allow "" as a file name, but some non-POSIX + hosts do (as an alias for "."), so allow "" if lstat does. */ + + struct stat st; + if (lstat (file, &st) == 0) + file_exists = true; + else if (errno != ENOENT || filelen == 0) + { + error (0, errno, "%s", quotef (file)); + return false; + } + } + + if (check_basic_portability + || (! file_exists && PATH_MAX_MINIMUM <= filelen)) + { + idx_t maxsize; + + if (check_basic_portability) + maxsize = _POSIX_PATH_MAX; + else + { + long int size; + char const *dir = (*file == '/' ? "/" : "."); + errno = 0; + size = pathconf (dir, _PC_PATH_MAX); + if (size < 0 && errno != 0) + { + error (0, errno, + _("%s: unable to determine maximum file name length"), + dir); + return false; + } + maxsize = MIN (size, MIN (SSIZE_MAX, IDX_MAX)); + } + + if (maxsize <= filelen) + { + error (0, 0, _("limit %td exceeded by length %td of file name %s"), + maxsize - 1, filelen, quoteaf (file)); + return false; + } + } + + /* Check whether pathconf (..., _PC_NAME_MAX) can be avoided, i.e., + whether all file name components are so short that they are valid + in any file system on this platform. If CHECK_BASIC_PORTABILITY, though, + it's more convenient to check component lengths below. */ + + check_component_lengths = check_basic_portability; + if (! check_component_lengths && ! file_exists) + { + for (start = file; *(start = component_start (start)); ) + { + size_t length = component_len (start); + + if (NAME_MAX_MINIMUM < length) + { + check_component_lengths = true; + break; + } + + start += length; + } + } + + if (check_component_lengths) + { + /* The limit on file name components for the current component. + This defaults to NAME_MAX_MINIMUM, for the sake of non-POSIX + systems (NFS, say?) where pathconf fails on "." or "/" with + errno == ENOENT. */ + idx_t name_max = NAME_MAX_MINIMUM; + + /* If nonzero, the known limit on file name components. */ + idx_t known_name_max = check_basic_portability ? _POSIX_NAME_MAX : 0; + + for (start = file; *(start = component_start (start)); ) + { + idx_t length; + + if (known_name_max) + name_max = known_name_max; + else + { + long int len; + char const *dir = (start == file ? "." : file); + char c = *start; + errno = 0; + *start = '\0'; + len = pathconf (dir, _PC_NAME_MAX); + *start = c; + if (0 <= len) + name_max = MIN (len, MIN (SSIZE_MAX, IDX_MAX)); + else + switch (errno) + { + case 0: + /* There is no limit. */ + name_max = IDX_MAX; + break; + + case ENOENT: + /* DIR does not exist; use its parent's maximum. */ + known_name_max = name_max; + break; + + default: + *start = '\0'; + error (0, errno, "%s", quotef (dir)); + *start = c; + return false; + } + } + + length = component_len (start); + + if (name_max < length) + { + char c = start[length]; + start[length] = '\0'; + error (0, 0, + _("limit %td exceeded by length %td " + "of file name component %s"), + name_max, length, quote (start)); + start[length] = c; + return false; + } + + start += length; + } + } + + return true; +} |