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Allow posix_spawn more often

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Now that we no longer open files after fork, we can correctly report errors
for failed file opens. So allow posix_spawn even if there's redirections.
This commit is contained in:
ridiculousfish 2019-01-29 00:40:55 -08:00
parent 2742267b9e
commit 084ff64f4f
1 changed files with 3 additions and 25 deletions
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28
src/exec.cpp
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@ -115,18 +115,6 @@ static bool redirection_is_to_real_file(const io_data_t *io) {
return result; return result;
} }
static bool chain_contains_redirection_to_real_file(const io_chain_t &io_chain) {
bool result = false;
for (size_t idx = 0; idx < io_chain.size(); idx++) {
const io_data_t *io = io_chain.at(idx).get();
if (redirection_is_to_real_file(io)) {
result = true;
break;
}
}
return result;
}
/// Returns the interpreter for the specified script. Returns NULL if file is not a script with a /// Returns the interpreter for the specified script. Returns NULL if file is not a script with a
/// shebang. /// shebang.
char *get_interpreter(const char *command, char *interpreter, size_t buff_size) { char *get_interpreter(const char *command, char *interpreter, size_t buff_size) {
@ -330,11 +318,9 @@ void internal_exec_helper(parser_t &parser, parsed_source_ref_t parsed_source, t
job_reap(false); job_reap(false);
} }
// Returns whether we can use posix spawn for a given process in a given job. Per // Returns whether we can use posix spawn for a given process in a given job.
// https://github.com/fish-shell/fish-shell/issues/364 , error handling for file redirections is too
// difficult with posix_spawn, so in that case we use fork/exec.
// //
// Furthermore, to avoid the race between the caller calling tcsetpgrp() and the client checking the // To avoid the race between the caller calling tcsetpgrp() and the client checking the
// foreground process group, we don't use posix_spawn if we're going to foreground the process. (If // foreground process group, we don't use posix_spawn if we're going to foreground the process. (If
// we use fork(), we can call tcsetpgrp after the fork, before the exec, and avoid the race). // we use fork(), we can call tcsetpgrp after the fork, before the exec, and avoid the race).
static bool can_use_posix_spawn_for_job(const std::shared_ptr<job_t> &job, static bool can_use_posix_spawn_for_job(const std::shared_ptr<job_t> &job,
@ -348,15 +334,7 @@ static bool can_use_posix_spawn_for_job(const std::shared_ptr<job_t> &job,
return false; return false;
} }
} }
return true;
// Now see if we have a redirection involving a file. The only one we allow is /dev/null, which
// we assume will not fail.
bool result = true;
if (chain_contains_redirection_to_real_file(job->block_io_chain()) ||
chain_contains_redirection_to_real_file(process->io_chain())) {
result = false;
}
return result;
} }
void internal_exec(env_stack_t &vars, job_t *j, const io_chain_t &all_ios) { void internal_exec(env_stack_t &vars, job_t *j, const io_chain_t &all_ios) {