[PATCH v2 5/7] Add early startup command file

[Andrew Burgess]

* Tom Tromey <tom@tromey.com> [2020-06-23 07:20:04 -0600]:

> This adds support for a gdb command file to be read early in startup.
> Code that wants to save an early setting can register a callback to be
> called to write to this file.  This code is not yet used, but will be
> in subsequent patches.
> 
> 2020-06-22  Tom Tromey  <tom@tromey.com>
> 
> 	* main.c (captured_main_1): Call read_startup_file.
> 	* cli/cli-setshow.h (write_startup_functions, add_startup_writer)
> 	(read_startup_file): Declare.
> 	(write_startup_setting_ftype): New typedef.
> 	* cli/cli-setshow.c (STARTUP_FILE): New define.
> 	(write_startup_functions, startup_file_read): New globals.
> 	(write_startup_file, add_startup_writer, read_startup_file): New
> 	functions.

I think that this patch needs some documentation in, at least, the
'@node Startup' section of the manual.

Also I think that if this config file is going to be generated as
~/.config/gdb/... then we should allow the gdbinit file to be moved
into that directory too, though obviously this would be a follow up
patch.

Thanks,
Andrew



> ---
>  gdb/ChangeLog         | 11 +++++++
>  gdb/cli/cli-setshow.c | 76 +++++++++++++++++++++++++++++++++++++++++++
>  gdb/cli/cli-setshow.h | 21 ++++++++++++
>  gdb/main.c            |  5 +++
>  4 files changed, 113 insertions(+)
> 
> diff --git a/gdb/cli/cli-setshow.c b/gdb/cli/cli-setshow.c
> index 19a5565bfe0..32e867160cb 100644
> --- a/gdb/cli/cli-setshow.c
> +++ b/gdb/cli/cli-setshow.c
> @@ -21,6 +21,8 @@
>  #include <ctype.h>
>  #include "arch-utils.h"
>  #include "observable.h"
> +#include "gdbsupport/pathstuff.h"
> +#include <vector>
>  
>  #include "ui-out.h"
>  
> @@ -29,6 +31,80 @@
>  #include "cli/cli-setshow.h"
>  #include "cli/cli-utils.h"
>  
> +/* File name for startup style.  */
> +
> +#define STARTUP_FILE "startup-commands"
> +
> +/* Callbacks that will be called to write out startup settings.  */
> +static std::vector<write_startup_setting_ftype *> write_startup_functions;
> +
> +/* True after gdb has read the startup file.  */
> +static bool startup_file_read;
> +
> +/* See cli-setshow.h.  */
> +
> +void
> +write_startup_file ()
> +{
> +  std::string config_dir = get_standard_config_dir ();
> +
> +  if (config_dir.empty ())
> +    {
> +      warning (_("Couldn't determine a path for the startup settings."));
> +      return;
> +    }
> +
> +  if (!mkdir_recursive (config_dir.c_str ()))
> +    {
> +      warning (_("Could not make config directory: %s"),
> +	       safe_strerror (errno));
> +      return;
> +    }
> +
> +  std::string fullname = config_dir + "/" + STARTUP_FILE;
> +  stdio_file outfile;
> +
> +  if (!outfile.open (fullname.c_str (), FOPEN_WT))
> +    perror_with_name (fullname.c_str ());
> +
> +  for (auto &callback : write_startup_functions)
> +    callback (&outfile);
> +}
> +
> +/* See cli-setshow.h.  */
> +
> +void
> +add_startup_writer (write_startup_setting_ftype *callback)
> +{
> +  write_startup_functions.push_back (callback);
> +}
> +
> +/* See cli-setshow.h.  */
> +
> +void
> +read_startup_file ()
> +{
> +  std::string config_dir = get_standard_config_dir ();
> +
> +  if (!config_dir.empty ())
> +    {
> +      std::string filename = config_dir + "/" + STARTUP_FILE;
> +      try
> +	{
> +	  source_script (filename.c_str (), 1);
> +	  /* If reading fails, we don't want to write the file -- it
> +	     might overwrite something.  So, we set this flag after
> +	     reading.  */
> +	  startup_file_read = true;
> +	}
> +      catch (const gdb_exception &)
> +	{
> +	  /* Ignore errors.  */
> +	}
> +    }
> +}
> +
> +
>  /* Return true if the change of command parameter should be notified.  */
>  
>  static int
> diff --git a/gdb/cli/cli-setshow.h b/gdb/cli/cli-setshow.h
> index 83e4984ed6c..35e229022ff 100644
> --- a/gdb/cli/cli-setshow.h
> +++ b/gdb/cli/cli-setshow.h
> @@ -62,4 +62,25 @@ extern std::string get_setshow_command_value_string (const cmd_list_element *c);
>  
>  extern void cmd_show_list (struct cmd_list_element *list, int from_tty);
>  
> +/* Write the file of gdb "set" commands that is read early in the
> +   startup sequence.  */
> +
> +extern void write_startup_file ();
> +
> +/* The type of a callback function that is used when writing the
> +   startup file.  */
> +
> +class ui_file;
> +typedef void write_startup_setting_ftype (ui_file *);
> +
> +/* Add a callback function that will be called when writing the
> +   startup sequence.  */
> +
> +extern void add_startup_writer (write_startup_setting_ftype *callback);
> +
> +/* Read the startup file.  This should only be called by the gdb
> +   startup sequence.  */
> +
> +extern void read_startup_file ();
> +
>  #endif /* CLI_CLI_SETSHOW_H */
> diff --git a/gdb/main.c b/gdb/main.c
> index 3649e4a2201..bd1f6d6b2c5 100644
> --- a/gdb/main.c
> +++ b/gdb/main.c
> @@ -35,6 +35,7 @@
>  #include "main.h"
>  #include "source.h"
>  #include "cli/cli-cmds.h"
> +#include "cli/cli-setshow.h"
>  #include "objfiles.h"
>  #include "auto-load.h"
>  #include "maint.h"
> @@ -933,6 +934,10 @@ captured_main_1 (struct captured_main_args *context)
>    /* Initialize all files.  */
>    gdb_init (gdb_program_name);
>  
> +  /* Set the startup style.  */
> +  if (!inhibit_gdbinit && !inhibit_home_gdbinit)
> +    read_startup_file ();
> +
>    /* Now that gdb_init has created the initial inferior, we're in
>       position to set args for that inferior.  */
>    if (set_args)
> -- 
> 2.17.2
>