btrfs-progs/help.c

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/*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public
* License v2 as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* 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., 59 Temple Place - Suite 330,
* Boston, MA 021110-1307, USA.
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <limits.h>
#include <getopt.h>
#include "commands.h"
#include "utils.h"
#include "help.h"
#define USAGE_SHORT 1U
#define USAGE_LONG 2U
#define USAGE_OPTIONS 4U
#define USAGE_LISTING 8U
static char argv0_buf[ARGV0_BUF_SIZE] = "btrfs";
void fixup_argv0(char **argv, const char *token)
{
int len = strlen(argv0_buf);
snprintf(argv0_buf + len, sizeof(argv0_buf) - len, " %s", token);
argv[0] = argv0_buf;
}
void set_argv0(char **argv)
{
strncpy(argv0_buf, argv[0], sizeof(argv0_buf));
argv0_buf[sizeof(argv0_buf) - 1] = 0;
}
int check_argc_exact(int nargs, int expected)
{
if (nargs != expected)
fprintf(stderr, "%s: exactly %d argument%s expected, %d given\n",
argv0_buf, expected,
expected > 1 ? "s" : "", nargs);
return nargs != expected;
}
int check_argc_min(int nargs, int expected)
{
if (nargs < expected) {
fprintf(stderr,
"%s: not enough arguments: %d but at least %d expected\n",
argv0_buf, nargs, expected);
return 1;
}
return 0;
}
int check_argc_max(int nargs, int expected)
{
if (nargs > expected) {
fprintf(stderr,
"%s: too many arguments: %d but at most %d expected\n",
argv0_buf, nargs, expected);
return 1;
}
return 0;
}
/*
* Preprocess @argv with getopt_long to reorder options and consume the "--"
* option separator.
* Unknown short and long options are reported, optionally the @usage is printed
* before exit.
*/
void clean_args_no_options(int argc, char *argv[], const char * const *usagestr)
{
static const struct option long_options[] = {
{NULL, 0, NULL, 0}
};
while (1) {
int c = getopt_long(argc, argv, "", long_options, NULL);
if (c < 0)
break;
switch (c) {
default:
if (usagestr)
usage(usagestr);
}
}
}
/*
* Same as clean_args_no_options but pass through arguments that could look
* like short options. Eg. resize which takes a negative resize argument like
* '-123M' .
*
* This accepts only two forms:
* - "-- option1 option2 ..."
* - "option1 option2 ..."
*/
void clean_args_no_options_relaxed(int argc, char *argv[])
{
if (argc <= 1)
return;
if (strcmp(argv[1], "--") == 0)
optind = 2;
}
static int do_usage_one_command(const char * const *usagestr,
unsigned int flags, FILE *outf)
{
int pad = 4;
const char *prefix = "usage: ";
const char *pad_listing = " ";
if (!usagestr || !*usagestr)
return -1;
if (flags & USAGE_LISTING)
prefix = pad_listing;
fputs(prefix, outf);
if (strchr(*usagestr, '\n') == NULL) {
fputs(*usagestr, outf);
} else {
const char *c = *usagestr;
const char *nprefix = " ";
if (flags & USAGE_LISTING)
nprefix = pad_listing;
for (c = *usagestr; *c; c++) {
fputc(*c, outf);
if (*c == '\n')
fputs(nprefix, outf);
}
}
usagestr++;
/* a short one-line description (mandatory) */
if ((flags & USAGE_SHORT) == 0)
return 0;
else if (!*usagestr)
return -2;
fputc('\n', outf);
if (flags & USAGE_LISTING)
pad = 8;
else
fputc('\n', outf);
fprintf(outf, "%*s%s\n", pad, "", *usagestr++);
/* a long (possibly multi-line) description (optional) */
if (!*usagestr || ((flags & USAGE_LONG) == 0))
return 0;
if (**usagestr)
fputc('\n', outf);
while (*usagestr && **usagestr)
fprintf(outf, "%*s%s\n", pad, "", *usagestr++);
/* options (optional) */
if (!*usagestr || ((flags & USAGE_OPTIONS) == 0))
return 0;
/*
* options (if present) should always (even if there is no long
* description) be prepended with an empty line, skip it
*/
usagestr++;
fputc('\n', outf);
while (*usagestr)
fprintf(outf, "%*s%s\n", pad, "", *usagestr++);
return 0;
}
static int usage_command_internal(const char * const *usagestr,
const char *token, int full, int lst,
int alias, FILE *outf)
{
unsigned int flags = 0;
int ret;
if (!alias)
flags |= USAGE_SHORT;
if (full)
flags |= USAGE_LONG | USAGE_OPTIONS;
if (lst)
flags |= USAGE_LISTING;
ret = do_usage_one_command(usagestr, flags, outf);
switch (ret) {
case -1:
fprintf(outf, "No usage for '%s'\n", token);
break;
case -2:
fprintf(outf, "No short description for '%s'\n", token);
break;
}
return ret;
}
static void usage_command_usagestr(const char * const *usagestr,
const char *token, int full, int err)
{
FILE *outf = err ? stderr : stdout;
int ret;
ret = usage_command_internal(usagestr, token, full, 0, 0, outf);
if (!ret)
fputc('\n', outf);
}
void usage_command(const struct cmd_struct *cmd, int full, int err)
{
usage_command_usagestr(cmd->usagestr, cmd->token, full, err);
}
__attribute__((noreturn))
void usage_unknown_option(const char * const *usagestr, char **argv)
{
int i;
int c;
int prev = 0;
/*
* Guess the command prefix, until the first option or argument
* specifier
*/
i = 0;
do {
c = usagestr[0][i];
if (c == '<' || c == '[' || (prev == ' ' && c == '-')) {
i--;
break;
}
prev = c;
i++;
} while (c);
/*
* Example:
*
* $ btrfs device add --unknown device path
* btrfs device add: unrecognized option '--unknown'
* Try 'btrfs device add --help' for more information
*/
fprintf(stderr, "%.*s: ", i, usagestr[0]);
if (!optopt) {
/*
* There's no better way to get the exact unrecognized token
* from getopt
*/
fprintf(stderr, "unrecognized option '%s'\n", argv[optind - 1]);
} else {
fprintf(stderr, "invalid option '%c'\n", optopt);
}
fprintf(stderr, "Try '%.*s --help' for more information\n", i, usagestr[0]);
exit(1);
}
__attribute__((noreturn))
void usage(const char * const *usagestr)
{
usage_command_usagestr(usagestr, NULL, 1, 1);
exit(1);
}
static void usage_command_group_internal(const struct cmd_group *grp, int full,
FILE *outf)
{
const struct cmd_struct *cmd = grp->commands;
int do_sep = 0;
for (; cmd->token; cmd++) {
if (cmd->flags & CMD_HIDDEN)
continue;
if (full && cmd != grp->commands)
fputc('\n', outf);
if (!cmd->next) {
if (do_sep) {
fputc('\n', outf);
do_sep = 0;
}
usage_command_internal(cmd->usagestr, cmd->token, full,
1, cmd->flags & CMD_ALIAS, outf);
if (cmd->flags & CMD_ALIAS)
putchar('\n');
continue;
}
/* this is an entry point to a nested command group */
if (!full && cmd != grp->commands)
fputc('\n', outf);
usage_command_group_internal(cmd->next, full, outf);
if (!full)
do_sep = 1;
}
}
void usage_command_group_short(const struct cmd_group *grp)
{
const char * const *usagestr = grp->usagestr;
FILE *outf = stdout;
const struct cmd_struct *cmd;
if (usagestr && *usagestr) {
fprintf(outf, "usage: %s\n", *usagestr++);
while (*usagestr)
fprintf(outf, " or: %s\n", *usagestr++);
}
fputc('\n', outf);
fprintf(outf, "Command groups:\n");
for (cmd = grp->commands; cmd->token; cmd++) {
if (cmd->flags & CMD_HIDDEN)
continue;
if (!cmd->next)
continue;
fprintf(outf, " %-16s %s\n", cmd->token, cmd->next->infostr);
}
fprintf(outf, "\nCommands:\n");
for (cmd = grp->commands; cmd->token; cmd++) {
if (cmd->flags & CMD_HIDDEN)
continue;
if (cmd->next)
continue;
fprintf(outf, " %-16s %s\n", cmd->token, cmd->usagestr[1]);
}
fputc('\n', outf);
fprintf(stderr, "For an overview of a given command use 'btrfs command --help'\n");
fprintf(stderr, "or 'btrfs [command...] --help --full' to print all available options.\n");
fprintf(stderr, "Any command name can be shortened as far as it stays unambiguous,\n");
fprintf(stderr, "however it is recommended to use full command names in scripts.\n");
fprintf(stderr, "All command groups have their manual page named 'btrfs-<group>'.\n");
}
void usage_command_group(const struct cmd_group *grp, int full, int err)
{
const char * const *usagestr = grp->usagestr;
FILE *outf = err ? stderr : stdout;
if (usagestr && *usagestr) {
fprintf(outf, "usage: %s\n", *usagestr++);
while (*usagestr)
fprintf(outf, " or: %s\n", *usagestr++);
}
fputc('\n', outf);
usage_command_group_internal(grp, full, outf);
fputc('\n', outf);
if (grp->infostr)
fprintf(outf, "%s\n", grp->infostr);
}
__attribute__((noreturn))
void help_unknown_token(const char *arg, const struct cmd_group *grp)
{
fprintf(stderr, "%s: unknown token '%s'\n", argv0_buf, arg);
usage_command_group(grp, 0, 1);
exit(1);
}
__attribute__((noreturn))
void help_ambiguous_token(const char *arg, const struct cmd_group *grp)
{
const struct cmd_struct *cmd = grp->commands;
fprintf(stderr, "%s: ambiguous token '%s'\n", argv0_buf, arg);
fprintf(stderr, "\nDid you mean one of these ?\n");
for (; cmd->token; cmd++) {
if (!prefixcmp(cmd->token, arg))
fprintf(stderr, "\t%s\n", cmd->token);
}
exit(1);
}
void help_command_group(const struct cmd_group *grp, int argc, char **argv)
{
int full = 0;
if (argc > 1) {
if (!strcmp(argv[1], "--full"))
full = 1;
}
usage_command_group(grp, full, 0);
}