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Revert "Split child_set_group from setup_child_process"

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This reverts commit f7b051905e.
It was meant for the major branch.
This commit is contained in:
Kurtis Rader 2017-08-13 15:26:52 -07:00
parent 7b443ac1d3
commit 4b1bc53f91
2 changed files with 16 additions and 23 deletions
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29
src/exec.cpp
View file

@ -517,8 +517,7 @@ void exec_job(parser_t &parser, job_t *j) {
//set to true if we end up forking for this process
bool child_forked = false;
bool child_spawned = false;
// bool block_child = !needs_keepalive;
bool block_child = true;
// bool child_blocked = false;
// The pipes the current process write to and read from. Unfortunately these can't be just
// allocated on the stack, since j->io wants shared_ptr.
@ -884,15 +883,13 @@ void exec_job(parser_t &parser, job_t *j) {
if (pid == 0) {
// This is the child process. Write out the contents of the pipeline.
p->pid = getpid();
blocked_pid = -1;
child_set_group(j, p);
setup_child_process(j, p, process_net_io_chain);
// Make child processes pause after executing setup_child_process() to give down-chain
// commands in the job a chance to join their process group and read their pipes.
// The process will be resumed when the next command in the chain is started.
if (block_child) {
if (pipes_to_next_command) {
kill(p->pid, SIGSTOP);
}
setup_child_process(j, p, process_net_io_chain);
exec_write_and_exit(block_output_io_buffer->fd, buffer, count, status);
} else {
@ -901,7 +898,7 @@ void exec_job(parser_t &parser, job_t *j) {
debug(2, L"Fork #%d, pid %d: internal block or function for '%ls'",
g_fork_count, pid, p->argv0());
child_forked = true;
if (block_child) {
if (pipes_to_next_command) {
debug(2, L"Blocking process %d waiting for next command in chain.\n", pid);
}
p->pid = pid;
@ -1017,15 +1014,13 @@ void exec_job(parser_t &parser, job_t *j) {
// This is the child process. Setup redirections, print correct output to
// stdout and stderr, and then exit.
p->pid = getpid();
blocked_pid = -1;
child_set_group(j, p);
setup_child_process(j, p, process_net_io_chain);
// Make child processes pause after executing setup_child_process() to give down-chain
// commands in the job a chance to join their process group and read their pipes.
// The process will be resumed when the next command in the chain is started.
if (block_child) {
if (pipes_to_next_command) {
kill(p->pid, SIGSTOP);
}
setup_child_process(j, p, process_net_io_chain);
do_builtin_io(outbuff, outbuff_len, errbuff, errbuff_len);
exit_without_destructors(p->status);
@ -1035,7 +1030,7 @@ void exec_job(parser_t &parser, job_t *j) {
debug(2, L"Fork #%d, pid %d: internal builtin for '%ls'", g_fork_count, pid,
p->argv0());
child_forked = true;
if (block_child) {
if (pipes_to_next_command) {
debug(2, L"Blocking process %d waiting for next command in chain.\n", pid);
}
p->pid = pid;
@ -1114,15 +1109,13 @@ void exec_job(parser_t &parser, job_t *j) {
if (pid == 0) {
// This is the child process.
p->pid = getpid();
blocked_pid = -1;
child_set_group(j, p);
setup_child_process(j, p, process_net_io_chain);
// Make child processes pause after executing setup_child_process() to give down-chain
// commands in the job a chance to join their process group and read their pipes.
// The process will be resumed when the next command in the chain is started.
if (block_child) {
if (pipes_to_next_command) {
kill(p->pid, SIGSTOP);
}
setup_child_process(j, p, process_net_io_chain);
safe_launch_process(p, actual_cmd, argv, envv);
// safe_launch_process _never_ returns...
@ -1135,7 +1128,7 @@ void exec_job(parser_t &parser, job_t *j) {
exec_error = true;
}
child_forked = true;
if (block_child) {
if (pipes_to_next_command) {
debug(2, L"Blocking process %d waiting for next command in chain.\n", pid);
}
}
@ -1154,7 +1147,7 @@ void exec_job(parser_t &parser, job_t *j) {
}
}
bool child_blocked = block_child && child_forked;
bool child_blocked = child_forked && pipes_to_next_command; //to make things clearer below
if (child_blocked) {
//we have to wait to ensure the child has set their progress group and is in SIGSTOP state
//otherwise, we can later call SIGCONT before they call SIGSTOP and they'll be blocked indefinitely.

10
src/postfork.cpp
View file

@ -125,9 +125,6 @@ bool child_set_group(job_t *j, process_t *p) {
/// and we can give the new process group control of the terminal if it's to run in the foreground. Note that
/// we can guarantee the child won't try to read from the terminal before we've had a chance to run this code,
/// because we haven't woken them up with a SIGCONT yet.
/// This musn't be called as a part of setup_child_process because that can hang indefinitely until data is
/// available to read/write in the case of IO_FILE, which means we'll never reach our SIGSTOP and everything
/// hangs.
bool set_child_group(job_t *j, pid_t child_pid) {
bool retval = true;
@ -262,11 +259,14 @@ static int handle_child_io(const io_chain_t &io_chain) {
int setup_child_process(job_t *j, process_t *p, const io_chain_t &io_chain) {
bool ok = true;
//p is zero when EXEC_INTERNAL
if (p) {
ok = child_set_group(j, p);
}
if (ok) {
//In the case of IO_FILE, this can hang until data is available to read/write!
ok = (0 == handle_child_io(io_chain));
if (p != 0 && !ok) {
debug_safe(0, "p!=0 && !ok");
exit_without_destructors(1);
}
}