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