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Diffstat (limited to 'src/readlink.c')
| -rw-r--r-- | src/readlink.c | 178 |
1 files changed, 178 insertions, 0 deletions
diff --git a/src/readlink.c b/src/readlink.c new file mode 100644 index 0000000..ac5e29b --- /dev/null +++ b/src/readlink.c @@ -0,0 +1,178 @@ +/* readlink -- display value of a symbolic link. + Copyright (C) 2002-2020 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 Dmitry V. Levin */ + +#include <config.h> +#include <stdio.h> +#include <getopt.h> +#include <sys/types.h> + +#include "system.h" +#include "canonicalize.h" +#include "error.h" +#include "areadlink.h" + +/* The official name of this program (e.g., no 'g' prefix). */ +#define PROGRAM_NAME "readlink" + +#define AUTHORS proper_name ("Dmitry V. Levin") + +/* If true, do not output the trailing newline. */ +static bool no_newline; + +/* If true, report error messages. */ +static bool verbose; + +static struct option const longopts[] = +{ + {"canonicalize", no_argument, NULL, 'f'}, + {"canonicalize-existing", no_argument, NULL, 'e'}, + {"canonicalize-missing", no_argument, NULL, 'm'}, + {"no-newline", no_argument, NULL, 'n'}, + {"quiet", no_argument, NULL, 'q'}, + {"silent", no_argument, NULL, 's'}, + {"verbose", no_argument, NULL, 'v'}, + {"zero", no_argument, NULL, 'z'}, + {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]... FILE...\n"), program_name); + fputs (_("Print value of a symbolic link or canonical file name\n\n"), + stdout); + fputs (_("\ + -f, --canonicalize canonicalize by following every symlink in\n\ + every component of the given name recursively;\ +\n\ + all but the last component must exist\n\ + -e, --canonicalize-existing canonicalize by following every symlink in\n\ + every component of the given name recursively,\ +\n\ + all components must exist\n\ +"), stdout); + fputs (_("\ + -m, --canonicalize-missing canonicalize by following every symlink in\n\ + every component of the given name recursively,\ +\n\ + without requirements on components existence\n\ + -n, --no-newline do not output the trailing delimiter\n\ + -q, --quiet\n\ + -s, --silent suppress most error messages (on by default)\n\ + -v, --verbose report error messages\n\ + -z, --zero end each output line with NUL, not newline\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) +{ + /* If not -1, use this method to canonicalize. */ + int can_mode = -1; + int status = EXIT_SUCCESS; + int optc; + bool use_nuls = 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, "efmnqsvz", longopts, NULL)) != -1) + { + switch (optc) + { + case 'e': + can_mode = CAN_EXISTING; + break; + case 'f': + can_mode = CAN_ALL_BUT_LAST; + break; + case 'm': + can_mode = CAN_MISSING; + break; + case 'n': + no_newline = true; + break; + case 'q': + case 's': + verbose = false; + break; + case 'v': + verbose = true; + break; + case 'z': + use_nuls = 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); + } + + if (argc - optind > 1) + { + if (no_newline) + error (0, 0, _("ignoring --no-newline with multiple arguments")); + no_newline = false; + } + + for (; optind < argc; ++optind) + { + const char *fname = argv[optind]; + char *value = (can_mode != -1 + ? canonicalize_filename_mode (fname, can_mode) + : areadlink_with_size (fname, 63)); + if (value) + { + fputs (value, stdout); + if (! no_newline) + putchar (use_nuls ? '\0' : '\n'); + free (value); + } + else + { + status = EXIT_FAILURE; + if (verbose) + error (0, errno, "%s", quotef (fname)); + } + } + + return status; +} |