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[RFA 2/4] Implement | (pipe) command.
- From: Philippe Waroquiers <philippe dot waroquiers at skynet dot be>
- To: gdb-patches at sourceware dot org
- Cc: Philippe Waroquiers <philippe dot waroquiers at skynet dot be>
- Date: Sat, 20 Apr 2019 23:21:51 +0200
- Subject: [RFA 2/4] Implement | (pipe) command.
- References: <20190420212153.30934-1-philippe.waroquiers@skynet.be>
The pipe command allows to run a GDB command, and pipe its output
to a shell command.
(gdb) help pipe
Send the output of a gdb command to a shell command.
Usage: pipe [COMMAND] | SHELL_COMMAND
Usage: | [COMMAND] | SHELL_COMMAND
Executes COMMAND and sends its output to SHELL_COMMAND.
With no COMMAND, repeat the last executed command
and send its output to SHELL_COMMAND.
(gdb)
For example:
(gdb) pipe print some_data_structure | grep -B3 -A3 something
The pipe character is defined as an alias for pipe command, so that
the above can be typed as:
(gdb) | print some_data_structure | grep -B3 -A3 something
If no GDB COMMAND is given, then the previous command is relaunched,
and its output is sent to the given SHELL_COMMAND.
gdb/ChangeLog
2019-04-20 Philippe Waroquiers <philippe.waroquiers@skynet.be>
* cli/cli-cmds.c (pipe_command): New function.
(_initialize_cli_cmds): Call add_com for pipe_command.
Define | as an alias for pipe.
cli/cli-decode.c (find_command_name_length): Recognize | as
a single character command.
---
gdb/cli/cli-cmds.c | 91 ++++++++++++++++++++++++++++++++++++++++++++
gdb/cli/cli-decode.c | 4 +-
2 files changed, 93 insertions(+), 2 deletions(-)
diff --git a/gdb/cli/cli-cmds.c b/gdb/cli/cli-cmds.c
index 5f3b973f06..6964f9e1ab 100644
--- a/gdb/cli/cli-cmds.c
+++ b/gdb/cli/cli-cmds.c
@@ -24,6 +24,8 @@
#include "completer.h"
#include "target.h" /* For baud_rate, remote_debug and remote_timeout. */
#include "common/gdb_wait.h" /* For shell escape implementation. */
+#include "gdbcmd.h"
+#include "gdbthread.h"
#include "gdb_regex.h" /* Used by apropos_command. */
#include "gdb_vfork.h"
#include "linespec.h"
@@ -854,6 +856,86 @@ edit_command (const char *arg, int from_tty)
xfree (p);
}
+/* Implementation of the "pipe" command. */
+
+static void
+pipe_command (const char *arg, int from_tty)
+{
+ FILE *to;
+ const char *shell_command = arg;
+
+ if (arg == NULL)
+ error (_("Missing \"[COMMAND] | SHELL_COMMAND\""));
+
+ while (*shell_command && *shell_command != '|')
+ shell_command++;
+
+ if (*shell_command != '|')
+ error (_("Missing | SHELL_COMMAND in \"| [COMMAND] | SHELL_COMMAND\""));
+
+ arg = skip_spaces (arg);
+ std::string gdb_cmd (arg, shell_command - arg);
+
+ if (gdb_cmd.length () == 0)
+ {
+ repeat_previous ();
+ gdb_cmd = skip_spaces (saved_command_line);
+ if (gdb_cmd.length () == 0)
+ error (_("No previous command to relaunch"));
+ }
+
+ shell_command++; /* skip the |. */
+ shell_command = skip_spaces (shell_command);
+ if (*shell_command == 0)
+ error (_("Missing SHELL_COMMAND in \"| [COMMAND] | SHELL_COMMAND\""));
+
+ to = popen (shell_command, "w");
+ if (to == NULL)
+ error (_("Error launching \"%s\""), shell_command);
+
+ try
+ {
+ std::string gdb_cmd_result;
+ {
+ /* In case GDB_CMD switches of inferior/thread/frame, the below
+ restores the inferior/thread/frame. */
+ scoped_restore_current_thread restore;
+
+ gdb_cmd_result = execute_command_to_string (gdb_cmd.c_str (),
+ from_tty);
+
+ if (fwrite (gdb_cmd_result.c_str (), 1, gdb_cmd_result.length (), to)
+ != gdb_cmd_result.length ())
+ {
+ error (_("error writing \"%s\" result to \"%s\", errno %s"),
+ gdb_cmd.c_str (), shell_command, safe_strerror (errno));
+ }
+ }
+ }
+ catch (const gdb_exception_error &ex)
+ {
+ pclose (to);
+ throw;
+ }
+
+ int shell_command_status = pclose (to);
+ if (shell_command_status < 0)
+ error (_("shell command \"%s\" errno %s"), shell_command,
+ safe_strerror (errno));
+ if (shell_command_status > 0)
+ {
+ if (WIFEXITED (shell_command_status))
+ warning (_("shell command \"%s\" exit status %d"), shell_command,
+ WEXITSTATUS (shell_command_status));
+ else if (WIFSIGNALED (shell_command_status))
+ warning (_("shell command \"%s\" exit with signal %d"), shell_command,
+ WTERMSIG (shell_command_status));
+ else
+ warning (_("shell command \"%s\" status %d"), shell_command,
+ shell_command_status);
+ }
+}
+
static void
list_command (const char *arg, int from_tty)
{
@@ -1845,6 +1927,15 @@ Uses EDITOR environment variable contents as editor (or ex as default)."));
c->completer = location_completer;
+ c = add_com ("pipe", class_support, pipe_command, _("\
+Send the output of a gdb command to a shell command.\n\
+Usage: pipe [COMMAND] | SHELL_COMMAND\n\
+Usage: | [COMMAND] | SHELL_COMMAND\n\
+Executes COMMAND and sends its output to SHELL_COMMAND.\n\
+With no COMMAND, repeat the last executed command\n\
+and send its output to SHELL_COMMAND."));
+ add_com_alias ("|", "pipe", class_support, 0);
+
add_com ("list", class_files, list_command, _("\
List specified function or line.\n\
With no argument, lists ten more lines after or around previous listing.\n\
diff --git a/gdb/cli/cli-decode.c b/gdb/cli/cli-decode.c
index 50430953c7..46051090cd 100644
--- a/gdb/cli/cli-decode.c
+++ b/gdb/cli/cli-decode.c
@@ -1311,9 +1311,9 @@ find_command_name_length (const char *text)
Note that this is larger than the character set allowed when
creating user-defined commands. */
- /* Recognize '!' as a single character command so that, e.g., "!ls"
+ /* Recognize the single character commands so that, e.g., "!ls"
works as expected. */
- if (*p == '!')
+ if (*p == '!' || *p == '|')
return 1;
while (isalnum (*p) || *p == '-' || *p == '_'
--
2.20.1