139 lines
3.8 KiB
C
139 lines
3.8 KiB
C
/*******************************************************************************
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Copyright(C) Jonas 'Sortie' Termansen 2013, 2014.
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This program is free software: you can redistribute it and/or modify it
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under the terms of the GNU General Public License as published by the Free
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Software Foundation, either version 3 of the License, or (at your option)
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any later version.
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This program is distributed in the hope that it will be useful, but WITHOUT
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ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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more details.
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You should have received a copy of the GNU General Public License along with
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this program. If not, see <http://www.gnu.org/licenses/>.
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pwd.c
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Prints the current working directory.
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*******************************************************************************/
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#include <errno.h>
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#include <error.h>
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#include <stdbool.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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static bool nul_or_slash(char c)
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{
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return !c || c == '/';
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}
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static bool next_elem_is_dot_or_dot_dot(const char* path)
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{
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return (path[0] == '.' && nul_or_slash(path[1])) ||
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(path[0] == '.' && path[1] == '.' && nul_or_slash(path[2]));
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}
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static bool is_path_absolute(const char* path)
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{
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size_t index = 0;
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if ( path[index++] != '/' )
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return false;
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while ( path[index] )
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{
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if ( next_elem_is_dot_or_dot_dot(path) )
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return false;
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while ( !nul_or_slash(path[index]) )
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index++;
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if ( path[index] == '/' )
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index++;
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}
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return true;
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}
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static void help(FILE* fp, const char* argv0)
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{
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fprintf(fp, "Usage: %s [OPTION]...\n", argv0);
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fprintf(fp, "Print the full filename of the current working directory.\n");
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fprintf(fp, "\n");
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fprintf(fp, " -L, --logical use PWD from environment, even if it contains symlinks\n");
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fprintf(fp, " -P, --physical avoid all symlinks\n");
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fprintf(fp, " --help display this help and exit\n");
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fprintf(fp, " --version output version information and exit\n");
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}
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static void version(FILE* fp, const char* argv0)
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{
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fprintf(fp, "%s (Sortix) %s\n", argv0, VERSIONSTR);
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fprintf(fp, "License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>.\n");
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fprintf(fp, "This is free software: you are free to change and redistribute it.\n");
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fprintf(fp, "There is NO WARRANTY, to the extent permitted by law.\n");
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}
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int main(int argc, char* argv[])
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{
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const char* argv0 = argv[0];
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bool physical = false;
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for ( int i = 1; i < argc; i++ )
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{
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const char* arg = argv[i];
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if ( arg[0] != '-' || !arg[1] )
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continue;
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argv[i] = NULL;
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if ( !strcmp(arg, "--") )
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break;
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if ( arg[1] != '-' )
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{
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char c;
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while ( (c = *++arg) ) switch ( c )
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{
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case 'L': physical = false; break;
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case 'P': physical = true; break;
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default:
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fprintf(stderr, "%s: unknown option -- '%c'\n", argv0, c);
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help(stderr, argv0);
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exit(1);
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}
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}
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else if ( !strcmp(arg, "--help") )
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help(stdout, argv0), exit(0);
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else if ( !strcmp(arg, "--version") )
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version(stdout, argv0), exit(0);
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else if ( !strcmp(arg, "--logical") )
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physical = false;
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else if ( !strcmp(arg, "--physical") )
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physical = true;
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else
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{
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fprintf(stderr, "%s: unknown option: %s\n", argv0, arg);
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help(stderr, argv0);
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exit(1);
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}
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}
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// The get_current_dir_name function will use the PWD variable if it is
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// accurate, so we'll need to unset it if it is inappropriate to use it.
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const char* pwd_env;
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if ( (pwd_env = getenv("PWD")) )
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{
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if ( physical || !is_path_absolute(pwd_env) )
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unsetenv("PWD");
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}
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char* pwd = get_current_dir_name();
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if ( !pwd )
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error(1, errno, "get_current_dir_name");
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printf("%s\n", pwd);
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if ( ferror(stdout) || fflush(stdout) == EOF )
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error(1, errno, "stdout");
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return 0;
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}
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