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sortix--sortix/utils/help.cpp
2013-12-17 14:30:33 +01:00

116 lines
2.8 KiB
C++

/*******************************************************************************
Copyright(C) Jonas 'Sortie' Termansen 2012, 2013.
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/>.
help.cpp
Prints a friendly message and print the names of everything in PATH.
*******************************************************************************/
#include <sys/stat.h>
#include <sys/wait.h>
#include <dirent.h>
#include <errno.h>
#include <error.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
int main(int /*argc*/, char* /*argv*/[])
{
printf("Please enter the name of one of the following programs:\n");
const char* path = getenv("PATH");
if ( !path )
return 0;
pid_t child_pid = -1;
if ( isatty(1) )
{
int pipe_fds[2];
if ( pipe(pipe_fds) )
error(1, errno, "pipe");
if ( (child_pid = fork()) < 0 )
error(1, errno, "fork");
if ( !child_pid )
{
dup2(pipe_fds[0], 0);
close(pipe_fds[0]);
close(pipe_fds[1]);
execlp("column", "column", NULL);
execlp("cat", "cat", NULL);
int ic;
while ( (ic = fgetc(stdin)) != EOF )
fputc(ic, stdout);
exit(0);
}
dup2(pipe_fds[1], 1);
close(pipe_fds[0]);
close(pipe_fds[1]);
}
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;
DIR* dir = opendir(dirname);
if ( !dir )
continue;
while ( struct dirent* entry = readdir(dir) )
{
if ( entry->d_name[0] == '.' )
continue;
struct stat st;
if ( fstatat(dirfd(dir), entry->d_name, &st, 0) )
continue;
if ( !S_ISREG(st.st_mode) )
continue;
if ( !(st.st_mode & 0111) )
continue;
printf("%s\n", entry->d_name);
}
closedir(dir);
}
free(dirname);
if ( 0 <= child_pid )
{
fflush(stdout);
close(1);
int exit_status;
waitpid(child_pid, &exit_status, 0);
if ( WIFSIGNALED(exit_status) )
exit(128 + WTERMSIG(exit_status));
if ( WIFEXITED(exit_status) && WEXITSTATUS(exit_status) )
exit(WEXITSTATUS(exit_status));
}
return 0;
}