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Shell: Allow control structures to appear in pipe sequences

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This makes commands like the following to be possible:
```sh
$ ls && for $(seq 10) { echo $it }
$ ls | for $(seq 1) { cat > foobar }
```
This commit is contained in:
AnotherTest 2020-09-07 20:49:53 +04:30 • committed by Andreas Kling
parent 7b5ead64a5
commit aa2df9277d
5 changed files with 73 additions and 41 deletions
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50
Shell/Shell.cpp
View file

@ -439,7 +439,7 @@ RefPtr<Job> Shell::run_command(const AST::Command& command)
}
// If the command is empty, store the redirections and apply them to all later commands.
if (command.argv.is_empty()) {
if (command.argv.is_empty() && !command.should_immediately_execute_next) {
m_global_redirections.append(command.redirections);
return nullptr;
}
@ -481,6 +481,25 @@ RefPtr<Job> Shell::run_command(const AST::Command& command)
return IterationDecision::Continue;
};
auto apply_rewirings = [&] {
for (auto& rewiring : rewirings) {
#ifdef SH_DEBUG
dbgprintf("in %s<%d>, dup2(%d, %d)\n", command.argv.is_empty() ? "(<Empty>)" : command.argv[0].characters(), getpid(), rewiring.dest_fd, rewiring.source_fd);
#endif
int rc = dup2(rewiring.dest_fd, rewiring.source_fd);
if (rc < 0) {
perror("dup2(run)");
return IterationDecision::Break;
}
// dest_fd is closed via the `fds` collector, but rewiring.other_pipe_end->dest_fd
// isn't yet in that collector when the first child spawns.
if (rewiring.other_pipe_end && close(rewiring.other_pipe_end->dest_fd) < 0)
perror("close other pipe end");
}
return IterationDecision::Continue;
};
for (auto& redirection : m_global_redirections) {
if (resolve_redirection(redirection) == IterationDecision::Break)
return nullptr;
@ -491,6 +510,19 @@ RefPtr<Job> Shell::run_command(const AST::Command& command)
return nullptr;
}
if (command.should_immediately_execute_next) {
ASSERT(command.argv.is_empty());
SavedFileDescriptors fds { rewirings };
if (apply_rewirings() == IterationDecision::Break)
return nullptr;
for (auto& next_in_chain : command.next_chain)
run_tail(next_in_chain, 0);
return nullptr;
}
int retval = 0;
if (run_builtin(command, rewirings, retval)) {
for (auto& next_in_chain : command.next_chain)
@ -524,20 +556,8 @@ RefPtr<Job> Shell::run_command(const AST::Command& command)
tcsetattr(0, TCSANOW, &default_termios);
for (auto& rewiring : rewirings) {
#ifdef SH_DEBUG
dbgprintf("in %s<%d>, dup2(%d, %d)\n", argv[0], getpid(), rewiring.dest_fd, rewiring.source_fd);
#endif
int rc = dup2(rewiring.dest_fd, rewiring.source_fd);
if (rc < 0) {
perror("dup2(run)");
return nullptr;
}
// dest_fd is closed via the `fds` collector, but rewiring.other_pipe_end->dest_fd
// isn't yet in that collector when the first child spawns.
if (rewiring.other_pipe_end && close(rewiring.other_pipe_end->dest_fd) < 0)
perror("close other pipe end");
}
if (apply_rewirings() == IterationDecision::Break)
return nullptr;
fds.collect();