static int pipelineExecProc(struct pipeline* pl, struct plProc *proc,
int prevStdoutFd, int stdinFd, int stdoutFd, int stderrFd,
void *otherEndBuf, size_t otherEndBufSize)
/* start a process in the pipeline, return the stdout fd of the process */
{
/* determine stdin/stdout to use */
int procStdinFd, procStdoutFd;
if (proc == pl->procs)
procStdinFd = stdinFd; /* first process in pipeline */
else
procStdinFd = prevStdoutFd;
if (proc->next == NULL)
procStdoutFd = stdoutFd; /* last process in pipeline */
else
prevStdoutFd = pipeCreate(&procStdoutFd);
/* start process */
if ((proc->pid = fork()) < 0)
errnoAbort("can't fork");
if (proc->pid == 0)
{
if (otherEndBuf != NULL)
plProcMemWrite(proc, procStdoutFd, stderrFd, otherEndBuf, otherEndBufSize);
else
plProcExecChild(proc, procStdinFd, procStdoutFd, stderrFd);
}
/* don't leave intermediate pipes open in parent */
if (proc != pl->procs)
safeClose(&procStdinFd);
if (proc->next != NULL)
safeClose(&procStdoutFd);
return prevStdoutFd;
}
static void execProcChild(struct pipeline* pl, struct plProc *proc,
int procStdinFd, int procStdoutFd, int stderrFd,
void *otherEndBuf, size_t otherEndBufSize)
/* handle child process setup after fork. This does not return */
{
if (otherEndBuf != NULL)
plProcMemWrite(proc, procStdoutFd, stderrFd, otherEndBuf, otherEndBufSize);
else
plProcExecChild(proc, procStdinFd, procStdoutFd, stderrFd);
}