github-mirror/fish-shell
github-mirror/fish-shell
2
0
Fork 0
mirror of https://github.com/fish-shell/fish-shell.git synced 2025-02-24 05:38:56 +08:00
Code Issues Actions Packages Projects Releases Wiki Activity

Revert "Be more judicious about when SIGSTOP is performed"

Browse Source 
This reverts commit abf6874a2df910453948a91ac3dc767e64aff6d8.
It was meant for the major branch.
This commit is contained in:
Kurtis Rader 2017-08-13 15:27:48 -07:00
parent 607d9e6aef
commit 8a1af4a38d
1 changed files with 30 additions and 45 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

55
src/exec.cpp
View File

@ -495,7 +495,6 @@ void exec_job(parser_t &parser, job_t *j) {
// //
// We are careful to set these to -1 when closed, so if we exit the loop abruptly, we can still // We are careful to set these to -1 when closed, so if we exit the loop abruptly, we can still
// close them. // close them.
bool pgrp_set = false;
static pid_t blocked_pid = -1; static pid_t blocked_pid = -1;
int pipe_current_read = -1, pipe_current_write = -1, pipe_next_read = -1; int pipe_current_read = -1, pipe_current_write = -1, pipe_next_read = -1;
for (std::unique_ptr<process_t> &unique_p : j->processes) { for (std::unique_ptr<process_t> &unique_p : j->processes) {
@ -517,7 +516,6 @@ void exec_job(parser_t &parser, job_t *j) {
//set to true if we end up forking for this process //set to true if we end up forking for this process
bool child_forked = false; bool child_forked = false;
bool child_spawned = false; bool child_spawned = false;
// bool child_blocked = false;
// The pipes the current process write to and read from. Unfortunately these can't be just // 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. // allocated on the stack, since j->io wants shared_ptr.
@ -639,6 +637,10 @@ void exec_job(parser_t &parser, job_t *j) {
switch (p->type) { switch (p->type) {
case INTERNAL_FUNCTION: { case INTERNAL_FUNCTION: {
//internal function never forks
//unblock previous (if any) to prevent hang
unblock_previous();
// Calls to function_get_definition might need to source a file as a part of // Calls to function_get_definition might need to source a file as a part of
// autoloading, hence there must be no blocks. // autoloading, hence there must be no blocks.
signal_unblock(); signal_unblock();
@ -814,12 +816,11 @@ void exec_job(parser_t &parser, job_t *j) {
const int fg = j->get_flag(JOB_FOREGROUND); const int fg = j->get_flag(JOB_FOREGROUND);
j->set_flag(JOB_FOREGROUND, false); j->set_flag(JOB_FOREGROUND, false);
signal_unblock();
//main loop is performing a blocking read from previous command's output //main loop is performing a blocking read from previous command's output
//make sure read source is not blocked //make sure read source is not blocked
unblock_previous(); unblock_previous();
signal_unblock();
p->status = builtin_run(parser, p->get_argv(), *builtin_io_streams); p->status = builtin_run(parser, p->get_argv(), *builtin_io_streams);
signal_block(); signal_block();
@ -887,9 +888,7 @@ void exec_job(parser_t &parser, job_t *j) {
// Make child processes pause after executing setup_child_process() to give down-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. // 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. // The process will be resumed when the next command in the chain is started.
if (pipes_to_next_command) {
kill(p->pid, SIGSTOP); kill(p->pid, SIGSTOP);
}
exec_write_and_exit(block_output_io_buffer->fd, buffer, count, status); exec_write_and_exit(block_output_io_buffer->fd, buffer, count, status);
} else { } else {
@ -898,9 +897,7 @@ void exec_job(parser_t &parser, job_t *j) {
debug(2, L"Fork #%d, pid %d: internal block or function for '%ls'", debug(2, L"Fork #%d, pid %d: internal block or function for '%ls'",
g_fork_count, pid, p->argv0()); g_fork_count, pid, p->argv0());
child_forked = true; child_forked = true;
if (pipes_to_next_command) {
debug(2, L"Blocking process %d waiting for next command in chain.\n", pid); debug(2, L"Blocking process %d waiting for next command in chain.\n", pid);
}
p->pid = pid; p->pid = pid;
} }
@ -1019,9 +1016,7 @@ void exec_job(parser_t &parser, job_t *j) {
// Make child processes pause after executing setup_child_process() to give down-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. // 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. // The process will be resumed when the next command in the chain is started.
if (pipes_to_next_command) {
kill(p->pid, SIGSTOP); kill(p->pid, SIGSTOP);
}
do_builtin_io(outbuff, outbuff_len, errbuff, errbuff_len); do_builtin_io(outbuff, outbuff_len, errbuff, errbuff_len);
exit_without_destructors(p->status); exit_without_destructors(p->status);
@ -1031,9 +1026,7 @@ void exec_job(parser_t &parser, job_t *j) {
debug(2, L"Fork #%d, pid %d: internal builtin for '%ls'", g_fork_count, pid, debug(2, L"Fork #%d, pid %d: internal builtin for '%ls'", g_fork_count, pid,
p->argv0()); p->argv0());
child_forked = true; child_forked = true;
if (pipes_to_next_command) {
debug(2, L"Blocking process %d waiting for next command in chain.\n", pid); debug(2, L"Blocking process %d waiting for next command in chain.\n", pid);
}
p->pid = pid; p->pid = pid;
} }
} }
@ -1114,9 +1107,7 @@ void exec_job(parser_t &parser, job_t *j) {
// Make child processes pause after executing setup_child_process() to give down-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. // 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. // The process will be resumed when the next command in the chain is started.
if (pipes_to_next_command) {
kill(p->pid, SIGSTOP); kill(p->pid, SIGSTOP);
}
safe_launch_process(p, actual_cmd, argv, envv); safe_launch_process(p, actual_cmd, argv, envv);
// safe_launch_process _never_ returns... // safe_launch_process _never_ returns...
@ -1129,11 +1120,9 @@ void exec_job(parser_t &parser, job_t *j) {
exec_error = true; exec_error = true;
} }
child_forked = true; child_forked = true;
if (pipes_to_next_command) {
debug(2, L"Blocking process %d waiting for next command in chain.\n", pid); debug(2, L"Blocking process %d waiting for next command in chain.\n", pid);
} }
} }
}
// This is the parent process. Store away information on the child, and possibly // This is the parent process. Store away information on the child, and possibly
// fice it control over the terminal. // fice it control over the terminal.
@ -1148,39 +1137,35 @@ void exec_job(parser_t &parser, job_t *j) {
} }
} }
bool child_blocked = child_forked && pipes_to_next_command; //to make things clearer below if (child_spawned) {
if (child_blocked) { //posix_spawn'd processes won't SIGSTOP
set_child_group(j, p->pid);
}
else if (child_forked) {
//we have to wait to ensure the child has set their progress group and is in SIGSTOP state //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. //otherwise, we can later call SIGCONT before they call SIGSTOP and they'll be blocked indefinitely.
//The child is SIGSTOP'd and is guaranteed to have called child_set_group() at this point. pid_t pid_status{};
if (waitpid(p->pid, &pid_status, WUNTRACED) != -1) {
//the child is SIGSTOP'd and is guaranteed to have called child_set_group() at this point.
//but we only need to call set_child_group for the first process in the group. //but we only need to call set_child_group for the first process in the group.
//If needs_keepalive is set, this has already been called for the keepalive process //If needs_keepalive is set, this has already been called for the keepalive process
pid_t pid_status{}; if (p->is_first_in_job) {
if (waitpid(p->pid, &pid_status, WUNTRACED) == -1) { set_child_group(j, p->pid);
exec_error = true;
debug(1, L"waitpid(%d) call in unblock_pid failed:!\n", p->pid);
wperror(L"waitpid");
break;
} }
//we are not unblocking the child via SIGCONT just yet to give the next process a chance to open //we are not unblocking the child via SIGCONT just yet to give the next process a chance to open
//the pipes and join the process group. We only unblock the last process in the job chain because //the pipes and join the process group. We only unblock the last process in the job chain because
//no one awaits it. //no one awaits it.
} }
//regardless of whether the child blocked or not: else {
if (child_spawned || child_forked) { debug(1, L"waitpid(%d) call in unblock_pid failed:!\n", p->pid);
//this should be called after waitpid if child_forked && pipes_to_next_command wperror(L"waitpid");
//it can be called at any time if child_spawned
if (!pgrp_set) {
set_child_group(j, p->pid);
//only once per job, and only once we've executed an external command for real
pgrp_set = true;
} }
} }
//if the command we ran _before_ this one was SIGSTOP'd to let this one catch up, unblock it now. //if the command we ran _before_ this one was SIGSTOP'd to let this one catch up, unblock it now.
//this must be after the wait_pid on the process we just started, if any. //this must be after the wait_pid on the process we just started, if any.
unblock_previous(); unblock_previous();
if (child_blocked) { if (child_forked) {
//store the newly-blocked command's PID so that it can be SIGCONT'd once the next process //store the newly-blocked command's PID so that it can be SIGCONT'd once the next process
//in the chain is started. That may be in this job or in another job. //in the chain is started. That may be in this job or in another job.
blocked_pid = p->pid; blocked_pid = p->pid;