daemon: New command_out and sh_out APIs

These APIs allow you to capture output from guest commands that
generate more output than the protocol limit allows.

Thanks: Nijin Ashok
Fixes: https://issues.redhat.com/browse/RHEL-80159

generator/actions_core.ml

@@ -2380,6 +2380,19 @@ result into a list of lines.
 
 See also: C<guestfs_sh_lines>" };
 
+  { defaults with
+    name = "command_out"; added = (1, 55, 6);
+    style = RErr, [StringList (PlainString, "arguments"); String (FileOut, "output")], [];
+    progress = true; cancellable = true;
+    test_excuse = "there is a separate test in the tests directory";
+    shortdesc = "run a command from the guest filesystem";
+    longdesc = "\
+This is the same as C<guestfs_command>, but streams the output
+back, handling the case where the output from the command is
+larger than the protocol limit.
+
+See also: C<guestfs_sh_out>" };
+
   { defaults with
     name = "statvfs"; added = (1, 9, 2);
     style = RStruct ("statbuf", "statvfs"), [String (Pathname, "path")], [];
@@ -3489,6 +3502,18 @@ into a list of lines.
 
 See also: C<guestfs_command_lines>" };
 
+  { defaults with
+    name = "sh_out"; added = (1, 55, 6);
+    style = RErr, [String (PlainString, "command"); String (FileOut, "output")], [];
+    test_excuse = "there is a separate test in the tests directory";
+    shortdesc = "run a command via the shell";
+    longdesc = "\
+This is the same as C<guestfs_sh>, but streams the output
+back, handling the case where the output from the command is
+larger than the protocol limit.
+
+See also: C<guestfs_command_out>" };
+
   { defaults with
     name = "glob_expand"; added = (1, 0, 50);
     (* Use Pathname here, and hence ABS_PATH (pattern,...) in

generator/proc_nr.ml

@@ -518,6 +518,8 @@ let proc_nr = [
 513, "inspect_get_build_id";
 514, "findfs_partuuid";
 515, "findfs_partlabel";
+516, "command_out";
+517, "sh_out";
 ]
 
 (* End of list.  If adding a new entry, add it at the end of the list