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[PATCH] gdb output pipelining to shell
- From: Abhijit Halder <abhijit dot k dot halder at gmail dot com>
- To: gdb-patches at sourceware dot org
- Date: Sat, 16 Jul 2011 14:12:35 +0530
- Subject: [PATCH] gdb output pipelining to shell
At present, there is no way to pass the output of a gdb command
directly to the shell for further processing. For example, something
similar is not permitted:
(gdb) thread apply all bt | less
This kind of feature is quite helpful in a scenario where a program
under debugger has hundreds of threads running and one wants to
examine the stack-trace of all the threads at once. The current
behaviour of gdb makes it somewhat difficult since the entire output
of gdb command (sometimes more than a number of pages) is dumped onto
the screen. One can always redirect the output of gdb using logging
mechanism, but that requires offline analysis of the log-file which
may not be acceptable in certain situations. Another option is to get
a shell using gdb's shell command, but that forces one every time to
source the shell profile. Furthermore, the log-file contains entire
debug information, parsing that huge file is resource and time
consuming.
I have implemented a feature which will allow one to pass the output
of any gdb command to the shell for further processing.
2011-07-09 Abhijit Halder <abhijit.k.halder@symantec.com>
* top.c (execute_command_to_pipe): New function.
(parse_for_shell_command): New function
(execute_command): Update.
* ui-file.c (gdb_modify_io): New function.
* ui-file.h (gdb_modify_io): Prototype.
top.c | 74 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
ui-file.c | 15 ++++++++++++
ui-file.h | 3 ++
3 files changed, 91 insertions(+), 1 deletion(-)
Regards,
Abhijit Halder
diff -rup src//gdb/top.c dst//gdb/top.c
--- src//gdb/top.c 2011-06-28 00:51:50.000000000 +0530
+++ dst//gdb/top.c 2011-07-15 13:48:19.943911979 +0530
@@ -48,6 +48,7 @@
#include "event-loop.h"
#include "gdbthread.h"
#include "python/python.h"
+#include "ui-file.h"
/* readline include files. */
#include "readline/readline.h"
@@ -358,6 +359,68 @@ prepare_execute_command (void)
return cleanup;
}
+char *
+parse_for_shell_command (char *p)
+{
+ char *sh_cmd, *cpos, *spos, *epos;
+ int quote_cnt = 0;
+
+ if ((sh_cmd = strchr (p, '|')) != NULL)
+ {
+ spos = p;
+ epos = p + strlen (p) - 1;
+
+ for (;;)
+ {
+ for (cpos = spos; (cpos = memchr (cpos, '"', (sh_cmd-cpos))) != NULL; cpos++)
+ quote_cnt++;
+ spos = (sh_cmd + 1);
+ if ((quote_cnt % 2) == 0 || (sh_cmd = strchr (spos, '|')) == NULL)
+ break;
+ }
+
+ if (sh_cmd == NULL)
+ return NULL;
+
+ cpos = spos;
+ while (isspace(*cpos))
+ cpos++;
+
+ if (*cpos != '{')
+ return NULL;
+
+ *cpos = ' ';
+
+ cpos = epos;
+ while (isspace(*cpos))
+ cpos--;
+
+ if (*cpos != '}')
+ return NULL;
+
+ *cpos = ' ';
+ }
+
+ if (sh_cmd)
+ *sh_cmd++ = '\0';
+
+ return sh_cmd;
+}
+
+/* Run execute_command for P and FROM_TTY. Write output in pipe,
+ do not display it to the screen. */
+
+void
+execute_command_to_pipe (char *p, int from_tty, FILE *pipe)
+{
+ FILE *file;
+
+ file = gdb_modify_io (gdb_stdout, pipe);
+ execute_command (p, from_tty);
+ pipe = gdb_modify_io (gdb_stdout, file);
+ pclose (pipe);
+}
+
/* Execute the line P as a command, in the current user context.
Pass FROM_TTY as second argument to the defining function. */
@@ -368,7 +431,16 @@ execute_command (char *p, int from_tty)
struct cmd_list_element *c;
enum language flang;
static int warned = 0;
- char *line;
+ char *line, *sh_cmd;
+
+ if ((sh_cmd = parse_for_shell_command (p)) != NULL)
+ {
+ FILE *pipe;
+
+ pipe = popen (sh_cmd, "w");
+ execute_command_to_pipe (p, from_tty, pipe);
+ return;
+ }
cleanup = prepare_execute_command ();
diff -rup src//gdb/ui-file.c dst//gdb/ui-file.c
--- src//gdb/ui-file.c 2011-05-14 11:14:36.000000000 +0530
+++ dst//gdb/ui-file.c 2011-07-15 13:49:34.999910332 +0530
@@ -617,6 +617,21 @@ struct ui_file *
stdio_fileopen (FILE *file)
{
return stdio_file_new (file, 0);
+
+}
+
+FILE *
+gdb_modify_io (struct ui_file *file, FILE *iostream_new)
+{
+ FILE *iostream_old;
+ struct stdio_file *stdio = ui_file_data (file);
+
+ if (stdio->magic != &stdio_file_magic)
+ internal_error (__FILE__, __LINE__,
+ _("gdb_modify_io: bad magic number"));
+ iostream_old = stdio->file;
+ stdio->file = iostream_new;
+ return iostream_old;
}
struct ui_file *
diff -rup src//gdb/ui-file.h dst//gdb/ui-file.h
--- src//gdb/ui-file.h 2011-05-13 22:58:20.000000000 +0530
+++ dst//gdb/ui-file.h 2011-07-15 13:48:54.603912199 +0530
@@ -126,6 +126,9 @@ extern struct ui_file *stdio_fileopen (F
/* Open NAME returning an STDIO based UI_FILE. */
extern struct ui_file *gdb_fopen (char *name, char *mode);
+/* Modify the file pointer of an STDIO based UI_FILE. */
+FILE *gdb_modify_io (struct ui_file *file, FILE *iostream_new);
+
/* Create a file which writes to both ONE and TWO. CLOSE_ONE
and CLOSE_TWO indicate whether the original files should be
closed when the new file is closed. */