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Diffstat (limited to '')
| -rw-r--r-- | src/mknod.c | 275 |
1 files changed, 275 insertions, 0 deletions
diff --git a/src/mknod.c b/src/mknod.c new file mode 100644 index 0000000..3f3f79a --- /dev/null +++ b/src/mknod.c @@ -0,0 +1,275 @@ +/* mknod -- make special files + Copyright (C) 1990-2020 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/>. */ + +/* Written by David MacKenzie <djm@ai.mit.edu> */ + +#include <config.h> +#include <stdio.h> +#include <getopt.h> +#include <sys/types.h> +#include <selinux/selinux.h> + +#include "system.h" +#include "die.h" +#include "error.h" +#include "modechange.h" +#include "quote.h" +#include "selinux.h" +#include "smack.h" +#include "xstrtol.h" + +/* The official name of this program (e.g., no 'g' prefix). */ +#define PROGRAM_NAME "mknod" + +#define AUTHORS proper_name ("David MacKenzie") + +static struct option const longopts[] = +{ + {GETOPT_SELINUX_CONTEXT_OPTION_DECL}, + {"mode", required_argument, NULL, 'm'}, + {GETOPT_HELP_OPTION_DECL}, + {GETOPT_VERSION_OPTION_DECL}, + {NULL, 0, NULL, 0} +}; + +void +usage (int status) +{ + if (status != EXIT_SUCCESS) + emit_try_help (); + else + { + printf (_("Usage: %s [OPTION]... NAME TYPE [MAJOR MINOR]\n"), + program_name); + fputs (_("\ +Create the special file NAME of the given TYPE.\n\ +"), stdout); + + emit_mandatory_arg_note (); + + fputs (_("\ + -m, --mode=MODE set file permission bits to MODE, not a=rw - umask\n\ +"), stdout); + fputs (_("\ + -Z set the SELinux security context to default type\n\ + --context[=CTX] like -Z, or if CTX is specified then set the SELinux\n\ + or SMACK security context to CTX\n\ +"), stdout); + fputs (HELP_OPTION_DESCRIPTION, stdout); + fputs (VERSION_OPTION_DESCRIPTION, stdout); + fputs (_("\ +\n\ +Both MAJOR and MINOR must be specified when TYPE is b, c, or u, and they\n\ +must be omitted when TYPE is p. If MAJOR or MINOR begins with 0x or 0X,\n\ +it is interpreted as hexadecimal; otherwise, if it begins with 0, as octal;\n\ +otherwise, as decimal. TYPE may be:\n\ +"), stdout); + fputs (_("\ +\n\ + b create a block (buffered) special file\n\ + c, u create a character (unbuffered) special file\n\ + p create a FIFO\n\ +"), stdout); + printf (USAGE_BUILTIN_WARNING, PROGRAM_NAME); + emit_ancillary_info (PROGRAM_NAME); + } + exit (status); +} + +int +main (int argc, char **argv) +{ + mode_t newmode; + char const *specified_mode = NULL; + int optc; + size_t expected_operands; + mode_t node_type; + char const *scontext = NULL; + bool set_security_context = false; + + 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, "m:Z", longopts, NULL)) != -1) + { + switch (optc) + { + case 'm': + specified_mode = optarg; + break; + case 'Z': + if (is_smack_enabled ()) + { + /* We don't yet support -Z to restore context with SMACK. */ + scontext = optarg; + } + else if (is_selinux_enabled () > 0) + { + if (optarg) + scontext = optarg; + else + set_security_context = true; + } + else if (optarg) + { + error (0, 0, + _("warning: ignoring --context; " + "it requires an SELinux/SMACK-enabled kernel")); + } + break; + case_GETOPT_HELP_CHAR; + case_GETOPT_VERSION_CHAR (PROGRAM_NAME, AUTHORS); + default: + usage (EXIT_FAILURE); + } + } + + newmode = MODE_RW_UGO; + if (specified_mode) + { + mode_t umask_value; + struct mode_change *change = mode_compile (specified_mode); + if (!change) + die (EXIT_FAILURE, 0, _("invalid mode")); + umask_value = umask (0); + umask (umask_value); + newmode = mode_adjust (newmode, false, umask_value, change, NULL); + free (change); + if (newmode & ~S_IRWXUGO) + die (EXIT_FAILURE, 0, + _("mode must specify only file permission bits")); + } + + /* If the number of arguments is 0 or 1, + or (if it's 2 or more and the second one starts with 'p'), then there + must be exactly two operands. Otherwise, there must be four. */ + expected_operands = (argc <= optind + || (optind + 1 < argc && argv[optind + 1][0] == 'p') + ? 2 : 4); + + if (argc - optind < expected_operands) + { + if (argc <= optind) + error (0, 0, _("missing operand")); + else + error (0, 0, _("missing operand after %s"), quote (argv[argc - 1])); + if (expected_operands == 4 && argc - optind == 2) + fprintf (stderr, "%s\n", + _("Special files require major and minor device numbers.")); + usage (EXIT_FAILURE); + } + + if (expected_operands < argc - optind) + { + error (0, 0, _("extra operand %s"), + quote (argv[optind + expected_operands])); + if (expected_operands == 2 && argc - optind == 4) + fprintf (stderr, "%s\n", + _("Fifos do not have major and minor device numbers.")); + usage (EXIT_FAILURE); + } + + if (scontext) + { + int ret = 0; + if (is_smack_enabled ()) + ret = smack_set_label_for_self (scontext); + else + ret = setfscreatecon (se_const (scontext)); + + if (ret < 0) + die (EXIT_FAILURE, errno, + _("failed to set default file creation context to %s"), + quote (scontext)); + } + + /* Only check the first character, to allow mnemonic usage like + 'mknod /dev/rst0 character 18 0'. */ + + switch (argv[optind + 1][0]) + { + case 'b': /* 'block' or 'buffered' */ +#ifndef S_IFBLK + die (EXIT_FAILURE, 0, _("block special files not supported")); +#else + node_type = S_IFBLK; +#endif + goto block_or_character; + + case 'c': /* 'character' */ + case 'u': /* 'unbuffered' */ +#ifndef S_IFCHR + die (EXIT_FAILURE, 0, _("character special files not supported")); +#else + node_type = S_IFCHR; +#endif + goto block_or_character; + + block_or_character: + { + char const *s_major = argv[optind + 2]; + char const *s_minor = argv[optind + 3]; + uintmax_t i_major, i_minor; + dev_t device; + + if (xstrtoumax (s_major, NULL, 0, &i_major, "") != LONGINT_OK + || i_major != (major_t) i_major) + die (EXIT_FAILURE, 0, + _("invalid major device number %s"), quote (s_major)); + + if (xstrtoumax (s_minor, NULL, 0, &i_minor, "") != LONGINT_OK + || i_minor != (minor_t) i_minor) + die (EXIT_FAILURE, 0, + _("invalid minor device number %s"), quote (s_minor)); + + device = makedev (i_major, i_minor); +#ifdef NODEV + if (device == NODEV) + die (EXIT_FAILURE, 0, _("invalid device %s %s"), + s_major, s_minor); +#endif + + if (set_security_context) + defaultcon (argv[optind], node_type); + + if (mknod (argv[optind], newmode | node_type, device) != 0) + die (EXIT_FAILURE, errno, "%s", quotef (argv[optind])); + } + break; + + case 'p': /* 'pipe' */ + if (set_security_context) + defaultcon (argv[optind], S_IFIFO); + if (mkfifo (argv[optind], newmode) != 0) + die (EXIT_FAILURE, errno, "%s", quotef (argv[optind])); + break; + + default: + error (0, 0, _("invalid device type %s"), quote (argv[optind + 1])); + usage (EXIT_FAILURE); + } + + if (specified_mode && lchmod (argv[optind], newmode) != 0) + die (EXIT_FAILURE, errno, _("cannot set permissions of %s"), + quoteaf (argv[optind])); + + return EXIT_SUCCESS; +} |