void do_pipe(char *cmds[MAXCMDS][MAXARGS], int nbcmd, int bg) {
int **fds;
int i, j;
int pgid, job;
char cmdsNames[MAXLINE] = "";
if(verbose)
printf("do_pipe: entering\n");
if((fds = malloc((nbcmd-1) * sizeof(int*))) == NULL){
if(verbose)
printf("do_pipe: malloc of rows failed\n");
return;
}
for(i=0 ; i<nbcmd-1 ; i++){
if ((fds[i] = malloc(2 * sizeof(int))) == NULL){
if(verbose)
printf("do_pipe: malloc of columns failed\n");
return;
}
}
for(i=0 ; i<nbcmd-1 ; i++)
pipe(fds[i]);
if(verbose)
printf("do_pipe: first case\n");
switch(pgid = fork()){
case -1:
if(verbose)
printf("do_pipe: fork failed\n");
return;
case 0:
setpgid(0, 0);
if(dup2(fds[0][1], STDOUT_FILENO) == -1 && verbose)
printf("do_pipe: dup2 failed\n");
for(i=0 ; i<nbcmd-1 ; i++){
close(fds[i][0]);
close(fds[i][1]);
}
if(execvp(cmds[0][0], cmds[0]) != 0){
perror("execvp");
exit(EXIT_FAILURE);
}
}
for(j=1 ; j<nbcmd-1 ; j++){
if(verbose){
printf("do_pipe: central case\n");
printf("do_pipe: pipe fds[%d]\n", j);
}
switch(fork()){
case -1:
if(verbose)
printf("do_pipe: fork failed\n");
return;
case 0:
setpgid(0, pgid);
dup2(fds[j-1][0], STDIN_FILENO);
dup2(fds[j][1], STDOUT_FILENO);
for(i=0 ; i<nbcmd-1 ; i++){
close(fds[i][0]);
close(fds[i][1]);
}
if(execvp(cmds[j][0], cmds[j]) != 0){
perror("execvp");
exit(EXIT_FAILURE);
}
}
}
if(verbose)
printf("do_pipe: last case\n");
switch(fork()){
case -1:
if(verbose)
printf("do_pipe: fork failed\n");
return;
case 0:
setpgid(0, pgid);
if(dup2(fds[nbcmd-2][0], STDIN_FILENO) == -1 && verbose)
printf("do_pipe: dup2 failed\n");
for(i=0 ; i<nbcmd-1 ; i++){
close(fds[i][0]);
close(fds[i][1]);
}
if(execvp(cmds[nbcmd-1][0], cmds[nbcmd-1]) != 0){
perror("execvp");
exit(EXIT_FAILURE);
}
}
for(i=0 ; i<nbcmd-1 ; i++){
close(fds[i][0]);
close(fds[i][1]);
}
for(i=0 ; i<nbcmd ; i++){
if(i!=0)
strcat(cmdsNames, " | ");
strcat(cmdsNames, cmds[i][0]);
}
if(bg)
job = jobs_addjob(pgid, BG, cmdsNames);
else
job = jobs_addjob(pgid, FG, cmdsNames);
if(!bg)
waitfg(pgid);
else
printf("[%d] (%d) %s\n",job , pgid, cmdsNames);
free(fds);
if(verbose)
printf("do_pipe: exiting\n");
return;
}
void eval(char *cmdline) {
char *token[MAXCMDS][MAXARGS]; /* token[i] is a command typed in the command line */
int nbcmd; /* number of commands typed in the command line */
int bg; /* should the job run in bg or fg? */
pid_t pid; /* process id */
sigset_t mask; /* signal mask */
char **argv;
/* Parse command line */
bg = parseline(cmdline, token, &nbcmd);
if (nbcmd > 1) /* a command pipeline has been typed in */
do_pipe(token, nbcmd, bg);
else { /* no pipeline, only one command */
argv = token[0];
if (!builtin_cmd(argv)) {
/*
* This is a little tricky. Block SIGCHLD, SIGINT, and SIGTSTP
* signals until we can add the job to the job list. This
* eliminates some nasty races between adding a job to the job
* list and the arrival of SIGCHLD, SIGINT, and SIGTSTP signals.
*/
if (sigemptyset(&mask) < 0)
unix_error("sigemptyset error");
if (sigaddset(&mask, SIGCHLD))
unix_error("sigaddset error");
if (sigaddset(&mask, SIGINT))
unix_error("sigaddset error");
if (sigaddset(&mask, SIGTSTP))
unix_error("sigaddset error");
if (sigprocmask(SIG_BLOCK, &mask, NULL) < 0)
unix_error("sigprocmask error");
/* Create a child process */
if ((pid = fork()) < 0)
unix_error("fork error");
/*
* Child process
*/
if (pid == 0) {
/* Child unblocks signals */
sigprocmask(SIG_UNBLOCK, &mask, NULL);
/* Each new job must get a new process group ID
so that the kernel doesn't send ctrl-c and ctrl-z
signals to all of the shell's jobs */
if (setpgid(0, 0) < 0)
unix_error("setpgid error");
/* Now load and run the program in the new job */
if (execvp(argv[0], argv) < 0) {
printf("%s: Command not found\n", argv[0]);
exit(EXIT_FAILURE);
}
}
/*
* Parent process
*/
/* Parent adds the job, and then unblocks signals so that
the signals handlers can run again */
jobs_addjob(pid, (bg == 1 ? BG : FG), cmdline);
sigprocmask(SIG_UNBLOCK, &mask, NULL);
if (!bg)
waitfg(pid);
else
printf("[%d] (%d) %s\n", jobs_pid2jid(pid), (int) pid, cmdline);
}
}
return;
}
void do_pipe(char *cmds[MAXCMDS][MAXARGS], int nbcmd, int bg) {
int fd[2][2], i;
pid_t pid;
if (verbose) printf("Entering pipe\n");
if (verbose) printf("Pipe creation\n");
if (pipe(fd[0]) == -1) {
if (verbose) printf("Error in pipe creation\n");
}
for (i = 0; i < nbcmd; i++) {
if (i == 0) {
switch(pid = fork()) {
case -1 :
if (verbose) unix_error("fork cmd 1 error");
case 0 :
if (verbose) printf("First son process\n");
setpgid(0, 0);
dup2(fd[0][1],STDOUT_FILENO);
close(fd[0][0]);
close(fd[0][1]);
execvp(cmds[0][0],cmds[0]);
printf("execvp error\n");
exit(EXIT_FAILURE);
default :
if (verbose) printf("Father process\n");
}
}
else if (i > 0 && i < nbcmd -1) {
switch(pid = fork()) {
case -1 :
unix_error("fork cmd 2 error");
case 0 :
if (verbose) printf("the %dth process\n",i);
assert(pipe(fd[i%2]) != -1);
setpgid(0, pid);
dup2(fd[(i+1)%2][0], STDIN_FILENO);
dup2(fd[i%2][1], STDOUT_FILENO);
close(fd[0][0]);
close(fd[0][1]);
close(fd[1][1]);
close(fd[1][0]);
execvp(cmds[i][0],cmds[i]);
printf("execvp 2 error\n");
exit(EXIT_FAILURE);
default :
close(fd[(i+1)%2][0]);
close(fd[(i+1)%2][1]);
}
}
else {
switch(pid = fork()) {
case -1 :
unix_error("fork cmd 2 error");
case 0 :
if (verbose) {
printf("Last process\n");
}
dup2(fd[(i+1)%2][0], STDIN_FILENO);
close(fd[(i+1)%2][0]);
close(fd[(i+1)%2][1]);
execvp(cmds[i][0],cmds[i]);
printf("execvp 2 error\n");
exit(EXIT_FAILURE);
default:
close(fd[(i+1)%2][0]);
close(fd[(i+1)%2][1]);
}
}
}
jobs_addjob(pid, (bg == 1 ? BG : FG), cmds[0][0]);
if (!bg) {
if (verbose) printf("pipe waiting fg \n");
waitfg(pid);
}
return;
}
