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Refactor child_set_group

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This commit is contained in:
ridiculousfish 2020-01-30 11:24:02 -08:00
parent a243e65939
commit 70195164d4
1 changed files with 54 additions and 57 deletions

111
src/postfork.cpp

@ -40,68 +40,65 @@
static char *get_interpreter(const char *command, char *buffer, size_t buff_size);
/// Report the error code \p err for a failed setpgid call.
static void report_setpgid_error(int err, const job_t *j, const process_t *p) {
char pid_buff[128];
char job_id_buff[128];
char getpgid_buff[128];
char job_pgid_buff[128];
char argv0[64];
char command[64];
format_long_safe(pid_buff, p->pid);
format_long_safe(job_id_buff, j->job_id());
format_long_safe(getpgid_buff, getpgid(p->pid));
format_long_safe(job_pgid_buff, j->pgid);
narrow_string_safe(argv0, p->argv0());
narrow_string_safe(command, j->command_wcstr());
debug_safe(1, "Could not send own process %s, '%s' in job %s, '%s' from group %s to group %s",
pid_buff, argv0, job_id_buff, command, getpgid_buff, job_pgid_buff);
if (is_windows_subsystem_for_linux() && errno == EPERM) {
debug_safe(1,
"Please update to Windows 10 1809/17763 or higher to address known issues "
"with process groups and zombie processes.");
}
errno = err;
safe_perror("setpgid");
}
/// Called only by the child to set its own process group (possibly creating a new group in the
/// process if it is the first in a JOB_CONTROL job.
/// Returns true on success, false on failure.
bool child_set_group(job_t *j, process_t *p) {
if (j->wants_job_control()) {
if (j->pgid == INVALID_PID) {
j->pgid = p->pid;
}
for (int i = 0; setpgid(p->pid, j->pgid) != 0; ++i) {
// Put a cap on how many times we retry so we are never stuck here
if (i < 100) {
if (errno == EPERM) {
// The setpgid(2) man page says that EPERM is returned only if attempts are made
// to move processes into groups across session boundaries (which can never be
// the case in fish, anywhere) or to change the process group ID of a session
// leader (again, can never be the case). I'm pretty sure this is a WSL bug, as
// we see the same with tcsetpgrp(2) in other places and it disappears on retry.
debug_safe(2, "setpgid(2) returned EPERM. Retrying");
continue;
} else if (errno == EINTR) {
// I don't think signals are blocked here. The parent (fish) redirected the
// signal handlers and `child_setup_process()` calls `signal_reset_handlers()`
// after we're done here (and not `signal_unblock()`). We're already in a loop,
// so let's just handle EINTR just in case.
continue;
}
}
char pid_buff[128];
char job_id_buff[128];
char getpgid_buff[128];
char job_pgid_buff[128];
char argv0[64];
char command[64];
format_long_safe(pid_buff, p->pid);
format_long_safe(job_id_buff, j->job_id());
format_long_safe(getpgid_buff, getpgid(p->pid));
format_long_safe(job_pgid_buff, j->pgid);
narrow_string_safe(argv0, p->argv0());
narrow_string_safe(command, j->command_wcstr());
debug_safe(
1, "Could not send own process %s, '%s' in job %s, '%s' from group %s to group %s",
pid_buff, argv0, job_id_buff, command, getpgid_buff, job_pgid_buff);
if (is_windows_subsystem_for_linux() && errno == EPERM) {
debug_safe(
1,
"Please update to Windows 10 1809/17763 or higher to address known issues "
"with process groups and zombie processes.");
}
safe_perror("setpgid");
return false;
}
} else {
j->pgid = getpgrp();
if (j->pgid == INVALID_PID) {
assert(j->pgroup_provenance == pgroup_provenance_t::first_external_proc &&
"pgroup should only be unset if we need to become the leader");
j->pgid = p->pid;
}
return true;
// Put a cap on how many times we retry so we are never stuck here.
for (int i = 0; i < 100; i++) {
if (setpgid(p->pid, j->pgid) == 0) {
return true;
} else if (errno == EPERM) {
// The setpgid(2) man page says that EPERM is returned only if attempts are made
// to move processes into groups across session boundaries (which can never be
// the case in fish, anywhere) or to change the process group ID of a session
// leader (again, can never be the case). I'm pretty sure this is a WSL bug, as
// we see the same with tcsetpgrp(2) in other places and it disappears on retry.
debug_safe(2, "setpgid(2) returned EPERM. Retrying");
continue;
} else if (errno == EINTR) {
// Retry on EINTR.
continue;
} else {
break;
}
}
report_setpgid_error(errno, j, p);
return false;
}
/// Called only by the parent only after a child forks and successfully calls child_set_group,