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mirror of git://sourceware.org/git/lvm2.git synced 2024-10-27 18:55:19 +03:00
lvm2/tools/lvm.c
David Teigland 1e2420bca8 commands: new method for defining commands
. Define a prototype for every lvm command.
. Match every user command with one definition.
. Generate help text and man pages from them.

The new file command-lines.in defines a prototype for every
unique lvm command.  A unique lvm command is a unique
combination of: command name + required option args +
required positional args.  Each of these prototypes also
includes the optional option args and optional positional
args that the command will accept, a description, and a
unique string ID for the definition.  Any valid command
will match one of the prototypes.

Here's an example of the lvresize command definitions from
command-lines.in, there are three unique lvresize commands:

lvresize --size SizeMB LV
OO: --alloc Alloc, --autobackup Bool, --force,
--nofsck, --nosync, --noudevsync, --reportformat String, --resizefs,
--stripes Number, --stripesize SizeKB, --poolmetadatasize SizeMB
OP: PV ...
ID: lvresize_by_size
DESC: Resize an LV by a specified size.

lvresize LV PV ...
OO: --alloc Alloc, --autobackup Bool, --force,
--nofsck, --nosync, --noudevsync,
--reportformat String, --resizefs, --stripes Number, --stripesize SizeKB
ID: lvresize_by_pv
DESC: Resize an LV by specified PV extents.
FLAGS: SECONDARY_SYNTAX

lvresize --poolmetadatasize SizeMB LV_thinpool
OO: --alloc Alloc, --autobackup Bool, --force,
--nofsck, --nosync, --noudevsync,
--reportformat String, --stripes Number, --stripesize SizeKB
OP: PV ...
ID: lvresize_pool_metadata_by_size
DESC: Resize a pool metadata SubLV by a specified size.

The three commands have separate definitions because they have
different required parameters.  Required parameters are specified
on the first line of the definition.  Optional options are
listed after OO, and optional positional args are listed after OP.

This data is used to generate corresponding command definition
structures for lvm in command-lines.h.  usage/help output is also
auto generated, so it is always in sync with the definitions.

Every user-entered command is compared against the set of
command structures, and matched with one.  An error is
reported if an entered command does not have the required
parameters for any definition.  The closest match is printed
as a suggestion, and running lvresize --help will display
the usage for each possible lvresize command.

The prototype syntax used for help/man output includes
required --option and positional args on the first line,
and optional --option and positional args enclosed in [ ]
on subsequent lines.

  command_name <required_opt_args> <required_pos_args>
          [ <optional_opt_args> ]
          [ <optional_pos_args> ]

Command definitions that are not to be advertised/suggested
have the flag SECONDARY_SYNTAX.  These commands will not be
printed in the normal help output.

Man page prototypes are also generated from the same original
command definitions, and are always in sync with the code
and help text.

Very early in command execution, a matching command definition
is found.  lvm then knows the operation being done, and that
the provided args conform to the definition.  This will allow
lots of ad hoc checking/validation to be removed throughout
the code.

Each command definition can also be routed to a specific
function to implement it.  The function is associated with
an enum value for the command definition (generated from
the ID string.)  These per-command-definition implementation
functions have not yet been created, so all commands
currently fall back to the existing per-command-name
implementation functions.

Using per-command-definition functions will allow lots of
code to be removed which tries to figure out what the
command is meant to do.  This is currently based on ad hoc
and complicated option analysis.  When using the new
functions, what the command is doing is already known
from the associated command definition.
2017-02-13 08:20:10 -06:00

348 lines
8.1 KiB
C

/*
* Copyright (C) 2001-2004 Sistina Software, Inc. All rights reserved.
* Copyright (C) 2004-2007 Red Hat, Inc. All rights reserved.
*
* This file is part of LVM2.
*
* This copyrighted material is made available to anyone wishing to use,
* modify, copy, or redistribute it subject to the terms and conditions
* of the GNU General Public License v.2.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software Foundation,
* Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "tools.h"
#include "lvm2cmdline.h"
int main(int argc, char **argv)
{
return lvm2_main(argc, argv);
}
#ifdef READLINE_SUPPORT
# include <readline/readline.h>
# include <readline/history.h>
# ifndef HAVE_RL_COMPLETION_MATCHES
# define rl_completion_matches(a, b) completion_matches((char *)a, b)
# define rl_completion_func_t CPPFunction
# endif
static struct cmdline_context *_cmdline;
/* List matching commands */
static char *_list_cmds(const char *text, int state)
{
static int i = 0;
static size_t len = 0;
/* Initialise if this is a new completion attempt */
if (!state) {
i = 0;
len = strlen(text);
}
while (i < _cmdline->num_command_names)
if (!strncmp(text, _cmdline->command_names[i++].name, len))
return strdup(_cmdline->command_names[i - 1].name);
return NULL;
}
/* List matching arguments */
static char *_list_args(const char *text, int state)
{
static int match_no = 0;
static size_t len = 0;
static struct command_name *cname;
/* Initialise if this is a new completion attempt */
if (!state) {
char *s = rl_line_buffer;
int j;
match_no = 0;
cname = NULL;
len = strlen(text);
/* Find start of first word in line buffer */
while (isspace(*s))
s++;
/* Look for word in list of command names */
for (j = 0; j < _cmdline->num_command_names; j++) {
const char *p;
char *q = s;
p = _cmdline->command_names[j].name;
while (*p == *q) {
p++;
q++;
}
if ((!*p) && *q == ' ') {
cname = _cmdline->command_names + j;
break;
}
}
}
if (!cname)
return NULL;
/* Short form arguments */
if (len < 3) {
while (match_no < cname->num_args) {
char s[3];
char c;
if (!(c = (_cmdline->arg_props +
cname->valid_args[match_no++])->short_arg))
continue;
sprintf(s, "-%c", c);
if (!strncmp(text, s, len))
return strdup(s);
}
}
/* Long form arguments */
if (match_no < cname->num_args)
match_no = cname->num_args;
while (match_no - cname->num_args < cname->num_args) {
const char *l;
l = (_cmdline->arg_props +
cname->valid_args[match_no++ - cname->num_args])->long_arg;
if (*(l + 2) && !strncmp(text, l, len))
return strdup(l);
}
return NULL;
}
/* Custom completion function */
static char **_completion(const char *text, int start_pos,
int end_pos __attribute__((unused)))
{
char **match_list = NULL;
int p = 0;
while (isspace((int) *(rl_line_buffer + p)))
p++;
/* First word should be one of our commands */
if (start_pos == p)
match_list = rl_completion_matches(text, _list_cmds);
else if (*text == '-')
match_list = rl_completion_matches(text, _list_args);
/* else other args */
/* No further completion */
rl_attempted_completion_over = 1;
return match_list;
}
static int _hist_file(char *buffer, size_t size)
{
char *e = getenv("HOME");
if (dm_snprintf(buffer, size, "%s/.lvm_history", e) < 0) {
log_error("$HOME/.lvm_history: path too long");
return 0;
}
return 1;
}
static void _read_history(struct cmd_context *cmd)
{
char hist_file[PATH_MAX];
if (!_hist_file(hist_file, sizeof(hist_file)))
return;
if (read_history(hist_file))
log_very_verbose("Couldn't read history from %s.", hist_file);
stifle_history(find_config_tree_int(cmd, shell_history_size_CFG, NULL));
}
static void _write_history(void)
{
char hist_file[PATH_MAX];
if (!_hist_file(hist_file, sizeof(hist_file)))
return;
if (write_history(hist_file))
log_very_verbose("Couldn't write history to %s.", hist_file);
}
static int _log_shell_command_status(struct cmd_context *cmd, int ret_code)
{
log_report_t log_state;
if (!cmd->cmd_report.log_rh)
return 1;
log_state = log_get_report_state();
return report_cmdlog(cmd->cmd_report.log_rh, REPORT_OBJECT_CMDLOG_NAME,
log_get_report_context_name(log_state.context),
log_get_report_object_type_name(log_state.object_type),
log_state.object_name, log_state.object_id,
log_state.object_group, log_state.object_group_id,
ret_code == ECMD_PROCESSED ? REPORT_OBJECT_CMDLOG_SUCCESS
: REPORT_OBJECT_CMDLOG_FAILURE,
stored_errno(), ret_code);
}
static void _discard_log_report_content(struct cmd_context *cmd)
{
if (cmd->cmd_report.log_rh)
dm_report_destroy_rows(cmd->cmd_report.log_rh);
}
int lvm_shell(struct cmd_context *cmd, struct cmdline_context *cmdline)
{
log_report_t saved_log_report_state = log_get_report_state();
char *orig_command_log_selection = NULL;
int is_lastlog_cmd = 0, argc, ret;
char *input = NULL, *args[MAX_ARGS], **argv;
rl_readline_name = "lvm";
rl_attempted_completion_function = (rl_completion_func_t *) _completion;
_read_history(cmd);
_cmdline = cmdline;
cmd->is_interactive = 1;
if (!report_format_init(cmd))
return_ECMD_FAILED;
orig_command_log_selection = dm_pool_strdup(cmd->libmem, find_config_tree_str(cmd, log_command_log_selection_CFG, NULL));
log_set_report_context(LOG_REPORT_CONTEXT_SHELL);
log_set_report_object_type(LOG_REPORT_OBJECT_TYPE_CMD);
while (1) {
report_reset_cmdlog_seqnum();
if (cmd->cmd_report.log_rh) {
/*
* If previous command was lastlog, reset log report selection to
* its original value as set by log/command_log_selection config setting.
*/
if (is_lastlog_cmd &&
!dm_report_set_selection(cmd->cmd_report.log_rh, orig_command_log_selection))
log_error("Failed to reset log report selection.");
}
log_set_report(cmd->cmd_report.log_rh);
log_set_report_object_name_and_id(NULL, NULL);
free(input);
input = readline("lvm> ");
/* EOF */
if (!input) {
_discard_log_report_content(cmd);
/* readline sends prompt to stdout */
printf("\n");
break;
}
/* empty line */
if (!*input) {
_discard_log_report_content(cmd);
continue;
}
add_history(input);
argv = args;
if (lvm_split(input, &argc, argv, MAX_ARGS) == MAX_ARGS) {
_discard_log_report_content(cmd);
log_error("Too many arguments, sorry.");
continue;
}
if (!argc) {
_discard_log_report_content(cmd);
continue;
}
if (!strcmp(argv[0], "lvm")) {
argv++;
argc--;
}
if (!argc) {
_discard_log_report_content(cmd);
continue;
}
log_set_report_object_name_and_id(argv[0], NULL);
is_lastlog_cmd = !strcmp(argv[0], "lastlog");
if (!is_lastlog_cmd)
_discard_log_report_content(cmd);
if (!strcmp(argv[0], "quit") || !strcmp(argv[0], "exit")) {
_discard_log_report_content(cmd);
remove_history(history_length - 1);
log_error("Exiting.");
break;
}
ret = lvm_run_command(cmd, argc, argv);
if (ret == ENO_SUCH_CMD)
log_error("No such command '%s'. Try 'help'.",
argv[0]);
if ((ret != ECMD_PROCESSED) && !error_message_produced()) {
log_debug(INTERNAL_ERROR "Failed command did not use log_error");
log_error("Command failed with status code %d.", ret);
}
_write_history();
if (!is_lastlog_cmd)
_log_shell_command_status(cmd, ret);
log_set_report(NULL);
dm_report_group_output_and_pop_all(cmd->cmd_report.report_group);
if (cmd->cmd_report.log_rh &&
!(dm_report_group_push(cmd->cmd_report.report_group,
cmd->cmd_report.log_rh,
(void *) cmd->cmd_report.log_name))) {
log_set_report(NULL);
log_error("Failed to add log report.");
break;
}
}
log_restore_report_state(saved_log_report_state);
cmd->is_interactive = 0;
free(input);
if (cmd->cmd_report.report_group) {
dm_report_group_destroy(cmd->cmd_report.report_group);
cmd->cmd_report.report_group = NULL;
}
if (cmd->cmd_report.log_rh) {
dm_report_free(cmd->cmd_report.log_rh);
cmd->cmd_report.report_group = NULL;
}
return 0;
}
#endif /* READLINE_SUPPORT */