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Shell: Rename {source,dest}_fd to {old,new}_fd

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This makes `Rewiring' much more understandable, and un-confuses the uses
of `dup2()'.
Also fixes `dup2()' bugs.
This commit is contained in:
AnotherTest 2020-10-27 21:38:37 +03:30 • committed by Andreas Kling
parent 0bc758d34a
commit f4b7a688b1
4 changed files with 74 additions and 54 deletions
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59
Shell/Shell.cpp
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@ -582,17 +582,17 @@ RefPtr<Job> Shell::run_command(const AST::Command& command)
}
auto& rewiring = rewiring_result.value();
if (rewiring->fd_action != AST::Rewiring::Close::ImmediatelyCloseDestination)
if (rewiring->fd_action != AST::Rewiring::Close::ImmediatelyCloseNew)
rewirings.append(*rewiring);
if (rewiring->fd_action == AST::Rewiring::Close::Source) {
fds.add(rewiring->source_fd);
} else if (rewiring->fd_action == AST::Rewiring::Close::Destination) {
if (rewiring->dest_fd != -1)
fds.add(rewiring->dest_fd);
} else if (rewiring->fd_action == AST::Rewiring::Close::ImmediatelyCloseDestination) {
fds.add(rewiring->dest_fd);
} else if (rewiring->fd_action == AST::Rewiring::Close::RefreshDestination) {
if (rewiring->fd_action == AST::Rewiring::Close::Old) {
fds.add(rewiring->old_fd);
} else if (rewiring->fd_action == AST::Rewiring::Close::New) {
if (rewiring->new_fd != -1)
fds.add(rewiring->new_fd);
} else if (rewiring->fd_action == AST::Rewiring::Close::ImmediatelyCloseNew) {
fds.add(rewiring->new_fd);
} else if (rewiring->fd_action == AST::Rewiring::Close::RefreshNew) {
ASSERT(rewiring->other_pipe_end);
int pipe_fd[2];
@ -601,8 +601,20 @@ RefPtr<Job> Shell::run_command(const AST::Command& command)
perror("pipe(RedirRefresh)");
return IterationDecision::Break;
}
rewiring->dest_fd = pipe_fd[1];
rewiring->other_pipe_end->dest_fd = pipe_fd[0]; // This fd will be added to the collection on one of the next iterations.
rewiring->new_fd = pipe_fd[1];
rewiring->other_pipe_end->new_fd = pipe_fd[0]; // This fd will be added to the collection on one of the next iterations.
fds.add(pipe_fd[1]);
} else if (rewiring->fd_action == AST::Rewiring::Close::RefreshOld) {
ASSERT(rewiring->other_pipe_end);
int pipe_fd[2];
int rc = pipe(pipe_fd);
if (rc < 0) {
perror("pipe(RedirRefresh)");
return IterationDecision::Break;
}
rewiring->old_fd = pipe_fd[1];
rewiring->other_pipe_end->old_fd = pipe_fd[0]; // This fd will be added to the collection on one of the next iterations.
fds.add(pipe_fd[1]);
}
return IterationDecision::Continue;
@ -611,17 +623,24 @@ RefPtr<Job> Shell::run_command(const AST::Command& command)
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);
dbgprintf("in %s<%d>, dup2(%d, %d)\n", command.argv.is_empty() ? "(<Empty>)" : command.argv[0].characters(), getpid(), rewiring.old_fd, rewiring.new_fd);
#endif
int rc = dup2(rewiring.dest_fd, rewiring.source_fd);
int rc = dup2(rewiring.old_fd, rewiring.new_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
// {new,old}_fd is closed via the `fds` collector, but rewiring.other_pipe_end->{new,old}_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 (rewiring.other_pipe_end) {
if (rewiring.fd_action == AST::Rewiring::Close::RefreshNew) {
if (rewiring.other_pipe_end && close(rewiring.other_pipe_end->new_fd) < 0)
perror("close other pipe end");
} else if (rewiring.fd_action == AST::Rewiring::Close::RefreshOld) {
if (rewiring.other_pipe_end && close(rewiring.other_pipe_end->old_fd) < 0)
perror("close other pipe end");
}
}
}
return IterationDecision::Continue;
@ -648,7 +667,7 @@ RefPtr<Job> Shell::run_command(const AST::Command& command)
SavedFileDescriptors fds { rewirings };
for (auto& rewiring : rewirings) {
int rc = dup2(rewiring.dest_fd, rewiring.source_fd);
int rc = dup2(rewiring.old_fd, rewiring.new_fd);
if (rc < 0) {
perror("dup2(run)");
return nullptr;
@ -878,7 +897,7 @@ NonnullRefPtrVector<Job> Shell::run_commands(Vector<AST::Command>& commands)
dbg() << "redir path " << (int)path_redir->direction << " " << path_redir->path << " <-> " << path_redir->fd;
} else if (redir.is_fd_redirection()) {
auto* fdredir = (const AST::FdRedirection*)&redir;
dbg() << "redir fd " << fdredir->source_fd << " -> " << fdredir->dest_fd;
dbg() << "redir fd " << fdredir->old_fd << " -> " << fdredir->new_fd;
} else if (redir.is_close_redirection()) {
auto close_redir = (const AST::CloseRedirection*)&redir;
dbg() << "close fd " << close_redir->fd;
@ -1662,7 +1681,7 @@ void FileDescriptionCollector::add(int fd)
SavedFileDescriptors::SavedFileDescriptors(const NonnullRefPtrVector<AST::Rewiring>& intended_rewirings)
{
for (auto& rewiring : intended_rewirings) {
int new_fd = dup(rewiring.source_fd);
int new_fd = dup(rewiring.new_fd);
if (new_fd < 0) {
if (errno != EBADF)
perror("dup");
@ -1676,7 +1695,7 @@ SavedFileDescriptors::SavedFileDescriptors(const NonnullRefPtrVector<AST::Rewiri
auto rc = fcntl(new_fd, F_SETFL, flags | FD_CLOEXEC);
ASSERT(rc == 0);
m_saves.append({ rewiring.source_fd, new_fd });
m_saves.append({ rewiring.new_fd, new_fd });
m_collector.add(new_fd);
}
}