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sortix--sortix/utils/which.cpp

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2012-12-09 13:10:59 -05:00
/*******************************************************************************
Copyright(C) Jonas 'Sortie' Termansen 2012.
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/>.
which.cpp
Locate a program in the PATH.
*******************************************************************************/
#include <sys/types.h>
#include <sys/stat.h>
#include <errno.h>
#include <error.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#if !defined(VERSIONSTR)
#define VERSIONSTR "unknown version"
#endif
bool Which(const char* cmd, const char* path, bool all)
{
if ( strchr(cmd, '/') )
{
struct stat st;
if ( stat(path, &st) )
{
printf("%s\n", cmd);
return true;
}
return false;
}
// Sortix doesn't support that the empty string means current directory.
bool found = false;
char* dirname = NULL;
while ( *path )
{
if ( dirname ) { free(dirname); dirname = NULL; }
size_t len = strcspn(path, ":");
if ( !len ) { path++; continue; }
dirname = (char*) malloc((len+1) * sizeof(char));
if ( !dirname )
error(1, errno, "malloc");
memcpy(dirname, path, len * sizeof(char));
dirname[len] = '\0';
path += len + 1;
int dirfd = open(dirname, O_RDONLY | O_DIRECTORY);
if ( dirfd < 0 )
{
if ( errno == EACCES )
error(1, errno, "%s", dirname);
// TODO: May be a security concern to continue;
if ( errno == ENOENT )
continue;
continue;
}
struct stat st;
int ret = fstatat(dirfd, cmd, &st, 0);
if ( ret != 0 )
continue;
printf("%s/%s\n", dirname, cmd);
found = true;
if ( !all )
break;
}
free(dirname);
return found;
}
void Usage(FILE* fp, const char* argv0)
{
fprintf(fp, "Usage: %s [-a] FILENAME...\n", argv0);
fprintf(fp, "Locate a program in the PATH.\n");
}
void Help(FILE* fp, const char* argv0)
{
Usage(fp, argv0);
}
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 all = false;
for ( int i = 1; i < argc; i++ )
{
const char* arg = argv[i];
if ( arg[0] != '-' )
continue;
argv[i] = NULL;
if ( !strcmp(arg, "--") )
break;
if ( arg[1] != '-' )
for ( size_t i = 1; arg[i]; i++ )
switch ( arg[i] )
{
case 'a': all = true; break;
default:
fprintf(stderr, "%s: unknown option -- '%c'\n", argv0, arg[i]);
Usage(stderr, argv0);
exit(1);
}
else if ( !strcmp(arg, "--help") ) { Help(stdout, argv0); exit(0); }
else if ( !strcmp(arg, "--usage") ) { Usage(stdout, argv0); exit(0); }
else if ( !strcmp(arg, "--version") ) { Version(stdout, argv0); exit(0); }
else
{
fprintf(stderr, "%s: unknown option: %s\n", argv0, arg);
Usage(stderr, argv0);
exit(1);
}
}
int num_args = 0;
for ( int i = 1; i < argc; i++ )
if ( argv[i] )
num_args++;
if ( !num_args )
{
fprintf(stderr, "%s: missing operand\n", argv0);
exit(1);
}
const char* path = getenv("PATH");
if ( !path )
{
fprintf(stderr, "%s: PATH variable is not set\n", argv0);
exit(1);
}
bool success = true;
for ( int i = 1; i < argc; i++ )
{
const char* arg = argv[i];
if ( !arg )
continue;
if ( !Which(arg, path, all) )
success = false;
}
return success ? 0 : 1;
}