94 lines
2.4 KiB
C
94 lines
2.4 KiB
C
/* teepipe -- tee output to both stdout and a program
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* Copyright (C) 2000 Bruce Guenter <bruceg@em.ca>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#include <signal.h>
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#include <stdlib.h>
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#include <string.h>
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#include <sys/types.h>
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#include <sys/wait.h>
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#include <unistd.h>
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#include "fork.h"
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void err(const char* msg)
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{
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write(2, "teepipe: Error: ", 16);
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write(2, msg, strlen(msg));
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write(2, "\n", 1);
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exit(1);
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}
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void err2(const char* msg1, const char* msg2)
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{
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write(2, "teepipe: Error: ", 16);
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write(2, msg1, strlen(msg1));
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write(2, msg2, strlen(msg2));
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write(2, "\n", 1);
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exit(1);
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}
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#define BUFSIZE 4096
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void main_loop(int fd)
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{
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for(;;) {
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char buf[BUFSIZE];
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ssize_t rd = read(0, buf, BUFSIZE);
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if(rd == 0 || rd == -1)
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break;
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if(write(fd, buf, rd) != rd)
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err("Error writing to program");
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if(write(1, buf, rd) != rd)
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err("Error writing to standard output");
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}
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}
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void exec_child(char** argv, int fd[2])
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{
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if(close(fd[1]) || close(0) ||
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dup2(fd[0], 0) || close(fd[0]))
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err("Error setting up pipe as standard input");
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if(close(1) || dup2(2, 1) != 1)
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err("Error setting up standard output");
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execvp(argv[0], argv);
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err2("Error executing", argv[0]);
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}
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int main(int argc, char** argv)
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{
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int fd[2];
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int status;
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pid_t pid;
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if(argc < 2)
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err("usage: teepipe program [args ...]");
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if(pipe(fd) == -1)
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err("Could not create pipe");
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pid = fork();
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if(pid == -1)
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err("Could not fork");
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if(!pid)
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exec_child(argv+1, fd);
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signal(SIGPIPE, SIG_IGN);
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signal(SIGCHLD, SIG_IGN);
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close(fd[0]);
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main_loop(fd[1]);
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if(close(fd[1]))
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err("Error closing output pipe");
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if(waitpid(pid, &status, 0) != pid)
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err("Error waiting for program to exit");
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return WIFEXITED(status) ? WEXITSTATUS(status) : 255;
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}
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