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sortix--sortix/utils/pwd.cpp
2014-12-04 18:12:50 +01:00

139 lines
3.8 KiB
C++

/*******************************************************************************
Copyright(C) Jonas 'Sortie' Termansen 2013, 2014.
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 <http://www.gnu.org/licenses/>.
pwd.cpp
Prints the current working directory.
*******************************************************************************/
#include <errno.h>
#include <error.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#if !defined(VERSIONSTR)
#define VERSIONSTR "unknown version"
#endif
static bool nul_or_slash(char c)
{
return !c || c == '/';
}
static bool next_elem_is_dot_or_dot_dot(const char* path)
{
return (path[0] == '.' && nul_or_slash(path[1])) ||
(path[0] == '.' && path[1] == '.' && nul_or_slash(path[2]));
}
static bool is_path_absolute(const char* path)
{
size_t index = 0;
if ( path[index++] != '/' )
return false;
while ( path[index] )
{
if ( next_elem_is_dot_or_dot_dot(path) )
return false;
while ( !nul_or_slash(path[index]) )
index++;
if ( path[index] == '/' )
index++;
}
return true;
}
static void help(FILE* fp, const char* argv0)
{
fprintf(fp, "Usage: %s [OPTION]...\n", argv0);
fprintf(fp, "Print the full filename of the current working directory.\n");
fprintf(fp, "\n");
fprintf(fp, " -L, --logical use PWD from environment, even if it contains symlinks\n");
fprintf(fp, " -P, --physical avoid all symlinks\n");
fprintf(fp, " --help display this help and exit\n");
fprintf(fp, " --version output version information and exit\n");
}
static void version(FILE* fp, const char* argv0)
{
fprintf(fp, "%s (Sortix) %s\n", argv0, VERSIONSTR);
fprintf(fp, "License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>.\n");
fprintf(fp, "This is free software: you are free to change and redistribute it.\n");
fprintf(fp, "There is NO WARRANTY, to the extent permitted by law.\n");
}
int main(int argc, char* argv[])
{
const char* argv0 = argv[0];
bool physical = false;
for ( int i = 1; i < argc; i++ )
{
const char* arg = argv[i];
if ( arg[0] != '-' || !arg[1] )
continue;
argv[i] = NULL;
if ( !strcmp(arg, "--") )
break;
if ( arg[1] != '-' )
{
while ( char c = *++arg ) switch ( c )
{
case 'L': physical = false; break;
case 'P': physical = true; break;
default:
fprintf(stderr, "%s: unknown option -- '%c'\n", argv0, c);
help(stderr, argv0);
exit(1);
}
}
else if ( !strcmp(arg, "--help") )
help(stdout, argv0), exit(0);
else if ( !strcmp(arg, "--version") )
version(stdout, argv0), exit(0);
else if ( !strcmp(arg, "--logical") )
physical = false;
else if ( !strcmp(arg, "--physical") )
physical = true;
else
{
fprintf(stderr, "%s: unknown option: %s\n", argv0, arg);
help(stderr, argv0);
exit(1);
}
}
// The get_current_dir_name function will use the PWD variable if it is
// accurate, so we'll need to unset it if it is inappropriate to use it.
if ( const char* pwd = getenv("PWD") )
{
if ( physical || !is_path_absolute(pwd) )
unsetenv("PWD");
}
char* pwd = get_current_dir_name();
if ( !pwd )
error(1, errno, "get_current_dir_name");
printf("%s\n", pwd);
if ( ferror(stdout) || fflush(stdout) == EOF )
error(1, errno, "stdout");
return 0;
}