115 lines
2.7 KiB
C
115 lines
2.7 KiB
C
/*
|
|
* Copyright (c) 2012, 2013 Jonas 'Sortie' Termansen.
|
|
*
|
|
* Permission to use, copy, modify, and distribute this software for any
|
|
* purpose with or without fee is hereby granted, provided that the above
|
|
* copyright notice and this permission notice appear in all copies.
|
|
*
|
|
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
|
|
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
|
|
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
|
|
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
|
|
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
|
|
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
|
|
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
|
|
*
|
|
* help.c
|
|
* 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(void)
|
|
{
|
|
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", (const char*) NULL);
|
|
execlp("cat", "cat", (const char*) 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;
|
|
struct dirent* entry;
|
|
while ( (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;
|
|
}
|