Initial work towards various IO cleanups with an eye to fixing https://github.com/fish-shell/fish-shell/issues/110

exec.cpp

@@ -49,7 +49,6 @@
 #include "expand.h"
 #include "signal.h"
 
-
 #include "parse_util.h"
 
 /**
@@ -490,7 +489,7 @@ static bool io_transmogrify(const io_chain_t &in_chain, io_chain_t &out_chain, s
 static void internal_exec_helper(parser_t &parser,
                                  const wchar_t *def,
                                  enum block_type_t block_type,
-                                 io_chain_t &ios)
+                                 const io_chain_t &ios)
 {
     io_chain_t morphed_chain;
     std::vector<int> opened_fds;
@@ -540,9 +539,10 @@ static bool can_use_posix_spawn_for_job(const job_t *job, const process_t *proce
     
     /* 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;
-    for (size_t idx = 0; idx < job->io.size(); idx++)
+    const io_chain_t &ios = job->io_chain();
+    for (size_t idx = 0; idx < ios.size(); idx++)
     {
-        const shared_ptr<const io_data_t> &io = job->io.at(idx);
+        const shared_ptr<const io_data_t> &io = ios.at(idx);
         if (redirection_is_to_real_file(io.get()))
         {
                 result = false;
@@ -621,9 +621,10 @@ void exec(parser_t &parser, job_t *j)
     }
 
     const io_buffer_t *input_redirect = NULL;
-    for (size_t idx = 0; idx < j->io.size(); idx++)
+    const io_chain_t &ios = j->io_chain();
+    for (size_t idx = 0; idx < ios.size(); idx++)
     {
-        const shared_ptr<io_data_t> &io = j->io.at(idx);
+        const shared_ptr<io_data_t> &io = ios.at(idx);
 
         if ((io->io_mode == IO_BUFFER))
         {
@@ -770,13 +771,14 @@ void exec(parser_t &parser, job_t *j)
             pipe_read.reset(new io_pipe_t(p->pipe_read_fd, true));
             /* Record the current read in pipe_read */
             pipe_read->pipe_fd[0] = pipe_current_read;
-            j->io.push_back(pipe_read);
+            j->append_io(pipe_read);
         }
 
         if (p->next)
         {
             pipe_write.reset(new io_pipe_t(p->pipe_write_fd, false));
-            j->io.push_back(pipe_write);
+            j->append_io(pipe_write);
+
         }
 
         /*
@@ -821,6 +823,10 @@ void exec(parser_t &parser, job_t *j)
             pipe_next_read = local_pipe[0];
         }
 
+        //fprintf(stderr, "before IO: ");
+        //io_print(j->io);
+
+
         switch (p->type)
         {
             case INTERNAL_FUNCTION:
@@ -873,13 +879,13 @@ void exec(parser_t &parser, job_t *j)
                     }
                     else
                     {
-                        j->io.push_back(io_buffer);
+                        j->append_io(io_buffer);
                     }
                 }
 
                 if (! exec_error)
                 {
-                    internal_exec_helper(parser, def.c_str(), TOP, j->io);
+                    internal_exec_helper(parser, def.c_str(), TOP, j->io_chain());
                 }
 
                 parser.allow_function();
@@ -915,7 +921,7 @@ void exec(parser_t &parser, job_t *j)
             case INTERNAL_BUILTIN:
             {
                 int builtin_stdin=0;
-                int close_stdin=0;
+                bool close_stdin = false;
 
                 /*
                   If this is the first process, check the io
@@ -959,7 +965,7 @@ void exec(parser_t &parser, job_t *j)
                                 }
                                 else
                                 {
-                                    close_stdin = 1;
+                                    close_stdin = true;
                                 }
 
                                 break;

io.cpp

@@ -202,6 +202,12 @@ void io_chain_t::push_back(const shared_ptr<io_data_t> &element)
     std::vector<shared_ptr<io_data_t> >::push_back(element);
 }
 
+void io_chain_t::push_front(const shared_ptr<io_data_t> &element)
+{
+    assert(element.get() != NULL);
+    this->insert(this->begin(), element);
+}
+
 void io_remove(io_chain_t &list, const shared_ptr<const io_data_t> &element)
 {
     list.remove(element);

io.h

@@ -188,6 +188,7 @@ public:
 
     void remove(const shared_ptr<const io_data_t> &element);
     void push_back(const shared_ptr<io_data_t> &element);
+    void push_front(const shared_ptr<io_data_t> &element);
 
     shared_ptr<const io_data_t> get_io_for_fd(int fd) const;
     shared_ptr<io_data_t> get_io_for_fd(int fd);

parser.cpp

@@ -1559,7 +1559,7 @@ void parser_t::parse_job_argument_list(process_t *p,
 
                 if (new_io.get() != NULL)
                 {
-                    j->io.push_back(new_io);
+                    j->append_io(new_io);
                 }
 
             }
@@ -2318,7 +2318,6 @@ static bool job_should_skip_elseif(const job_t *job, const block_t *current_bloc
 void parser_t::eval_job(tokenizer_t *tok)
 {
     ASSERT_IS_MAIN_THREAD();
-    job_t *j;
 
     int start_pos = job_start_pos = tok_get_pos(tok);
     long long t1=0, t2=0, t3=0;
@@ -2341,7 +2340,7 @@ void parser_t::eval_job(tokenizer_t *tok)
     {
         case TOK_STRING:
         {
-            j = this->job_create();
+            job_t *j = this->job_create();
             job_set_flag(j, JOB_FOREGROUND, 1);
             job_set_flag(j, JOB_TERMINAL, job_get_flag(j, JOB_CONTROL));
             job_set_flag(j, JOB_TERMINAL, job_get_flag(j, JOB_CONTROL) \

postfork.cpp

@@ -37,6 +37,8 @@
 /** pipe error */
 #define LOCAL_PIPE_ERROR "An error occurred while setting up pipe"
 
+static bool log_redirections = false;
+
 /* Cover for debug_safe that can take an int. The format string should expect a %s */
 static void debug_safe_int(int level, const char *format, int val)
 {
@@ -164,11 +166,11 @@ static void free_redirected_fds_from_pipes(io_chain_t &io_chain)
 
    \return 0 on sucess, -1 on failiure
 */
-static int handle_child_io(io_chain_t &io_chain)
+static int handle_child_io(const io_chain_t &io_chain)
 {
-
+    //fprintf(stderr, "child IO for %d\n", getpid());
     close_unused_internal_pipes(io_chain);
-    free_redirected_fds_from_pipes(io_chain);
+    //free_redirected_fds_from_pipes(io_chain);
     for (size_t idx = 0; idx < io_chain.size(); idx++)
     {
         io_data_t *io = io_chain.at(idx).get();
@@ -183,6 +185,7 @@ static int handle_child_io(io_chain_t &io_chain)
         {
             case IO_CLOSE:
             {
+                if (log_redirections) fprintf(stderr, "%d: close %d\n", getpid(), io->fd);
                 if (close(io->fd))
                 {
                     debug_safe_int(0, "Failed to close file descriptor %s", io->fd);
@@ -232,13 +235,17 @@ static int handle_child_io(io_chain_t &io_chain)
 
             case IO_FD:
             {
+                int old_fd = static_cast<const io_fd_t *>(io)->old_fd;
+                if (log_redirections) fprintf(stderr, "%d: fd dup %d to %d\n", getpid(), old_fd, io->fd);
+
                 /*
                   This call will sometimes fail, but that is ok,
                   this is just a precausion.
                 */
                 close(io->fd);
 
-                if (dup2(static_cast<const io_fd_t *>(io)->old_fd, io->fd) == -1)
+
+                if (dup2(old_fd, io->fd) == -1)
                 {
                     debug_safe_int(1, FD_ERROR, io->fd);
                     safe_perror("dup2");
@@ -262,6 +269,7 @@ static int handle_child_io(io_chain_t &io_chain)
                              io->pipe_fd[0],
                              io->pipe_fd[1]);
                 */
+                if (log_redirections) fprintf(stderr, "%d: %s dup %d to %d\n", getpid(), io->io_mode == IO_BUFFER ? "buffer" : "pipe", io_pipe->pipe_fd[write_pipe_idx], io->fd);
                 if (dup2(io_pipe->pipe_fd[write_pipe_idx], io->fd) != io->fd)
                 {
                     debug_safe(1, LOCAL_PIPE_ERROR);
@@ -295,7 +303,7 @@ int setup_child_process(job_t *j, process_t *p)
 
     if (ok)
     {
-        ok = (0 == handle_child_io(j->io));
+        ok = (0 == handle_child_io(j->io_chain()));
         if (p != 0 && ! ok)
         {
             exit_without_destructors(1);
@@ -436,19 +444,19 @@ bool fork_actions_make_spawn_properties(posix_spawnattr_t *attr, posix_spawn_fil
         err = posix_spawnattr_setsigmask(attr, &sigmask);
 
     /* Make sure that our pipes don't use an fd that the redirection itself wants to use */
-    free_redirected_fds_from_pipes(j->io);
+    //free_redirected_fds_from_pipes(j->io);
 
     /* Close unused internal pipes */
     std::vector<int> files_to_close;
-    get_unused_internal_pipes(files_to_close, j->io);
+    get_unused_internal_pipes(files_to_close, j->io_chain());
     for (size_t i = 0; ! err && i < files_to_close.size(); i++)
     {
         err = posix_spawn_file_actions_addclose(actions, files_to_close.at(i));
     }
 
-    for (size_t idx = 0; idx < j->io.size(); idx++)
+    for (size_t idx = 0; idx < j->io_chain().size(); idx++)
     {
-        shared_ptr<const io_data_t> io = j->io.at(idx);
+        shared_ptr<const io_data_t> io = j->io_chain().at(idx);
 
         if (io->io_mode == IO_FD)
         {

proc.cpp

@@ -542,11 +542,11 @@ process_t::~process_t()
 job_t::job_t(job_id_t jobid) :
     command_str(),
     command_narrow(),
+    io(),
     first_process(NULL),
     pgid(0),
     tmodes(),
     job_id(jobid),
-    io(),
     flags(0)
 {
 }
@@ -876,9 +876,9 @@ static int select_try(job_t *j)
 
     FD_ZERO(&fds);
 
-    for (size_t idx = 0; idx < j->io.size(); idx++)
+    for (size_t idx = 0; idx < j->io_chain().size(); idx++)
     {
-        const io_data_t *io = j->io.at(idx).get();
+        const io_data_t *io = j->io_chain().at(idx).get();
         if (io->io_mode == IO_BUFFER)
         {
             CAST_INIT(const io_pipe_t *, io_pipe, io);
@@ -917,9 +917,9 @@ static void read_try(job_t *j)
     /*
       Find the last buffer, which is the one we want to read from
     */
-    for (size_t idx = 0; idx < j->io.size(); idx++)
+    for (size_t idx = 0; idx < j->io_chain().size(); idx++)
     {
-        io_data_t *d = j->io.at(idx).get();
+        io_data_t *d = j->io_chain().at(idx).get();
         if (d->io_mode == IO_BUFFER)
         {
             buff = static_cast<io_buffer_t *>(d);

proc.h

@@ -272,6 +272,7 @@ void release_job_id(job_id_t jobid);
     A struct represeting a job. A job is basically a pipeline of one
     or more processes and a couple of flags.
  */
+class parser_t;
 class job_t
 {
     /**
@@ -284,6 +285,10 @@ class job_t
     /* narrow copy so we don't have to convert after fork */
     narrow_string_rep_t command_narrow;
 
+    /** List of all IO redirections for this job. */
+    io_chain_t io;
+    friend void exec(parser_t &parser, job_t *j);
+
     /* No copying */
     job_t(const job_t &rhs);
     void operator=(const job_t &);
@@ -350,13 +355,14 @@ public:
     */
     const job_id_t job_id;
 
-    /** List of all IO redirections for this job. */
-    io_chain_t io;
-
     /**
        Bitset containing information about the job. A combination of the JOB_* constants.
     */
     unsigned int flags;
+
+    const io_chain_t &io_chain() const { return this->io; }
+
+    void append_io(const shared_ptr<io_data_t> & new_io) { this->io.push_back(new_io); }
 };
 
 /**

share/functions/eval.fish

@@ -19,6 +19,19 @@ function eval -S -d "Evaluate parameters as a command"
 		status --job-control full
 	end
 
+        # rfish: To eval 'foo', we construct a block "begin ; foo; end <&3 3<&-"
+        # The 'eval2_inner' is a param to 'begin' itself; I believe it does nothing.
+        # Note the redirections are also within the quotes.
+        #
+        # We then pipe this to 'source 3<&0' which dup2's 3 to stdin.
+        #
+        # You might expect that the dup2(3, stdin) should overwrite stdin,
+        # and therefore prevent 'source' from reading the piped-in block. This doesn't happen
+        # because when you pipe to a builtin, we don't overwrite stdin with the read end
+        # of the block; instead we set a separate fd in a variable 'builtin_stdin', which is
+        # what it reads from. So builtins are magic in that, in pipes, their stdin
+        # is not fd 0.
+
 	echo "begin; $argv "\n" ;end eval2_inner <&3 3<&-" | source 3<&0
 	set -l res $status
 

tests/test1.in

@@ -94,6 +94,11 @@ else
 end
 echo Test 5 $sta
 
+# Verify that we can turn stderr into stdout and then pipe it.
+# Note that the order here seems unspecified - 'errput' appears before 'output', why?
+echo Test redirections
+begin ; echo output ; echo errput 1>&2  ; end 2>&1 | tee /tmp/tee_test.txt ; cat /tmp/tee_test.txt
+
 # echo tests
 
 echo 'abc\ndef'

tests/test1.out

@@ -18,6 +18,11 @@ Test  pass
 Test 3 pass
 Test 4 pass
 Test 5 pass
+Test redirections
+errput
+output
+errput
+output
 abc\ndef
 abc
 def