void do_fork_exec(char *cmdline, int *pid, int *stdin_fd, int *stdout_fd,
int *stderr_fd)
{
int inpipe[2], outpipe[2], errpipe[2];
if (pipe(inpipe) || pipe(outpipe) || (stderr_fd && pipe(errpipe))) {
perror("pipe");
exit(1);
}
switch (*pid = fork()) {
case -1:
perror("fork");
exit(-1);
case 0:
if (stderr_fd) {
fix_fds(inpipe[0], outpipe[1], errpipe[1]);
} else
fix_fds(inpipe[0], outpipe[1], 2);
do_exec(cmdline);
exit(-1);
default:;
}
close(inpipe[0]);
close(outpipe[1]);
*stdin_fd = inpipe[1];
*stdout_fd = outpipe[0];
if (stderr_fd) {
close(errpipe[1]);
*stderr_fd = errpipe[0];
}
}
void do_fork_exec(const char *cmdline, int *pid, int *stdin_fd, int *stdout_fd,
int *stderr_fd)
{
int inpipe[2], outpipe[2], errpipe[2];
if (socketpair(AF_UNIX, SOCK_STREAM, 0, inpipe) ||
socketpair(AF_UNIX, SOCK_STREAM, 0, outpipe) ||
(stderr_fd && socketpair(AF_UNIX, SOCK_STREAM, 0, errpipe))) {
perror("socketpair");
exit(1);
}
switch (*pid = fork()) {
case -1:
perror("fork");
exit(-1);
case 0:
if (stderr_fd) {
fix_fds(inpipe[0], outpipe[1], errpipe[1]);
} else
fix_fds(inpipe[0], outpipe[1], 2);
if (exec_func != NULL)
exec_func(cmdline);
exit(-1);
default:;
}
close(inpipe[0]);
close(outpipe[1]);
*stdin_fd = inpipe[1];
*stdout_fd = outpipe[0];
if (stderr_fd) {
close(errpipe[1]);
*stderr_fd = errpipe[0];
}
}
bool
daemonize(void)
{
pid_t pid, sid;
/* Fork off the parent process */
pid = fork();
if (pid < 0) {
return false;
}
/* If we got a good PID, then we are the parent and can exit */
if (pid > 0) {
exit(EXIT_SUCCESS);
}
/* now in forked child */
/* Fork again, to become a real daemon */
pid = fork();
if (pid < 0) {
exit(1);
} else if (pid > 0) {
exit(EXIT_SUCCESS);
}
/* Change the file mode mask */
umask(0);
/* Create a new SID for the child process */
sid = setsid();
if (sid < 0) {
/* we should log something here... */
return false;
}
/* Change the current working directory */
(void)chdir("/"); /* ignore errors */
/* Close out the standard file descriptors */
close(STDIN_FILENO);
close(STDOUT_FILENO),
close(STDERR_FILENO);
/* Replace standard file descriptors with /dev/null */
fix_fds();
return true;
}
int execute(const char *file, char * const*args) {
if(strcmp(file, "exit") == 0) {
kill(getpid(), SIGINT);
exit(0);
}
pid_t childProc = fork();
int saved_stdout = dup(STDOUT_FILENO);
int saved_stdin = dup(STDIN_FILENO);
if(childProc >= 0) {
if(childProc == 0) {
if(!fix_fds()) {
exit(0);
}
execvp(file, args);
fprintf(stderr, "Error: %s\n", strerror(errno));
exit(0);
}
else {
if(!background) {
children[nchildren++] = childProc;
}
int status;
if(!background) {
waitpid(childProc, &status, 0);
nchildren--;
}
else {
int pid;
while((pid=waitpid(-1, &status, WNOHANG)) > 0) {
printf("PID %d exited.\n", pid);
}
}
restore_fds(saved_stdin, saved_stdout);
return status;
}
}
else {
fprintf(stderr, "Error: %s\n", strerror(errno));
}
return -1;
}
void run_cmd(char * const *args, int *cmds, int numcmds) {
int s_stdin = dup(STDIN_FILENO);
int s_stdout = dup(STDOUT_FILENO);
if(numcmds <= 0) {
return;
}
int fds[2*(numcmds-1)];
for(int i=0; i<numcmds-1; i++) {
if(pipe(fds + i*2) < 0) {
fprintf(stderr, "Pipe error on line %d", __LINE__);
perror("");
restore_fds(s_stdin, s_stdout);
return;
}
}
int childpid;
for(int i=0; i<numcmds; i++) {
int index = cmds[i];
childpid = fork();
if(childpid == 0) {
if(!fix_fds()) {
return;
}
// child proc
//fprintf(stderr, "%d\n", i);
if(i < numcmds-1) {
//fprintf(stderr, "Duping stdout for cmd %s\n", *(args + index));
if(dup2(fds[i*2 + 1], 1) < 0) {
fprintf(stderr, "Dup2 error on line %d", __LINE__);
perror("");
// restore_fds(s_stdin, s_stdout);
exit(0);
}
}
if(i > 0) {
//fprintf(stderr, "Duping stdin for cmd %s\n", *(args + index));
if(dup2(fds[i*2-2], 0) < 0) {
fprintf(stderr, "Dup2 error on line %d\n", __LINE__);
fprintf(stderr, "File descriptor: %d", fds[i*2-2]);
perror("");
// restore_fds(s_stdin, s_stdout);
// exit(0);
kill(getppid(), SIGINT);
exit(0);
}
}
for(int j=0; j<numcmds*2-2; j++) {
close(fds[j]);
}
//fprintf(stderr, "Exec cmd %s\n", *(args + index));
execvp(*(args + index), args + index);
exit(0);
}
else if(childpid < 0) {
fprintf(stderr, "Fork Error on line %d", __LINE__);
perror("");
// restore_fds(s_stdin, s_stdout);
exit(0);
}
else if(!background) {
children[nchildren++] = childpid;
}
}
for(int i=0; i<2*(numcmds-1); i++) {
close(fds[i]);
}
int status;
if(!background) {
for(int i=0; i<numcmds; i++) {
wait(&status);
nchildren--;
}
}
else {
int pid;
while((pid=waitpid(-1, &status, WNOHANG)) > 0) {
fprintf(stderr, "PID %d exited.\n", pid);
}
}
restore_fds(s_stdin, s_stdout);
}
