grub/commands/test.c
cjwatson 07197f2322 2009-09-14 Colin Watson <cjwatson@ubuntu.com>
* commands/test.c (get_fileinfo): Return immediately if
	grub_fs_probe fails.
2009-09-14 19:57:45 +00:00

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/* test.c -- The test command.. */
/*
* GRUB -- GRand Unified Bootloader
* Copyright (C) 2005,2007 Free Software Foundation, Inc.
*
* GRUB is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* GRUB 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 GRUB. If not, see <http://www.gnu.org/licenses/>.
*/
#include <grub/dl.h>
#include <grub/misc.h>
#include <grub/mm.h>
#include <grub/env.h>
#include <grub/fs.h>
#include <grub/device.h>
#include <grub/file.h>
#include <grub/command.h>
/* A simple implementation for signed numbers. */
static int
grub_strtosl (char *arg, char **end, int base)
{
if (arg[0] == '-')
return -grub_strtoul (arg + 1, end, base);
return grub_strtoul (arg, end, base);
}
/* Parse a test expression starting from *argn. */
static int
test_parse (char **args, int *argn, int argc)
{
int ret = 0, discard = 0, invert = 0;
int file_exists;
struct grub_dirhook_info file_info;
auto void update_val (int val);
auto void get_fileinfo (char *pathname);
/* Take care of discarding and inverting. */
void update_val (int val)
{
if (! discard)
ret = invert ? ! val : val;
invert = discard = 0;
}
/* Check if file exists and fetch its information. */
void get_fileinfo (char *path)
{
char *filename, *pathname;
char *device_name;
grub_fs_t fs;
grub_device_t dev;
/* A hook for iterating directories. */
auto int find_file (const char *cur_filename,
const struct grub_dirhook_info *info);
int find_file (const char *cur_filename,
const struct grub_dirhook_info *info)
{
if ((info->case_insensitive ? grub_strcasecmp (cur_filename, filename)
: grub_strcmp (cur_filename, filename)) == 0)
{
file_info = *info;
file_exists = 1;
return 1;
}
return 0;
}
file_exists = 0;
device_name = grub_file_get_device_name (path);
dev = grub_device_open (device_name);
if (! dev)
{
grub_free (device_name);
return;
}
fs = grub_fs_probe (dev);
if (! fs)
{
grub_free (device_name);
grub_device_close (dev);
return;
}
pathname = grub_strchr (path, ')');
if (! pathname)
pathname = path;
else
pathname++;
/* Remove trailing '/'. */
while (*pathname && pathname[grub_strlen (pathname) - 1] == '/')
pathname[grub_strlen (pathname) - 1] = 0;
/* Split into path and filename. */
filename = grub_strrchr (pathname, '/');
if (! filename)
{
path = grub_strdup ("/");
filename = pathname;
}
else
{
filename++;
path = grub_strdup (pathname);
path[filename - pathname] = 0;
}
/* It's the whole device. */
if (! *pathname)
{
file_exists = 1;
grub_memset (&file_info, 0, sizeof (file_info));
/* Root is always a directory. */
file_info.dir = 1;
/* Fetch writing time. */
file_info.mtimeset = 0;
if (fs->mtime)
{
if (! fs->mtime (dev, &file_info.mtime))
file_info.mtimeset = 1;
grub_errno = GRUB_ERR_NONE;
}
}
else
(fs->dir) (dev, path, find_file);
grub_device_close (dev);
grub_free (path);
grub_free (device_name);
}
/* Here we have the real parsing. */
while (*argn < argc)
{
/* First try 3 argument tests. */
if (*argn + 2 < argc)
{
/* String tests. */
if (grub_strcmp (args[*argn + 1], "=") == 0
|| grub_strcmp (args[*argn + 1], "==") == 0)
{
update_val (grub_strcmp (args[*argn], args[*argn + 2]) == 0);
(*argn) += 3;
continue;
}
if (grub_strcmp (args[*argn + 1], "!=") == 0)
{
update_val (grub_strcmp (args[*argn], args[*argn + 2]) != 0);
(*argn) += 3;
continue;
}
/* GRUB extension: lexicographical sorting. */
if (grub_strcmp (args[*argn + 1], "<") == 0)
{
update_val (grub_strcmp (args[*argn], args[*argn + 2]) < 0);
(*argn) += 3;
continue;
}
if (grub_strcmp (args[*argn + 1], "<=") == 0)
{
update_val (grub_strcmp (args[*argn], args[*argn + 2]) <= 0);
(*argn) += 3;
continue;
}
if (grub_strcmp (args[*argn + 1], ">") == 0)
{
update_val (grub_strcmp (args[*argn], args[*argn + 2]) > 0);
(*argn) += 3;
continue;
}
if (grub_strcmp (args[*argn + 1], ">=") == 0)
{
update_val (grub_strcmp (args[*argn], args[*argn + 2]) >= 0);
(*argn) += 3;
continue;
}
/* Number tests. */
if (grub_strcmp (args[*argn + 1], "-eq") == 0)
{
update_val (grub_strtosl (args[*argn], 0, 0)
== grub_strtosl (args[*argn + 2], 0, 0));
(*argn) += 3;
continue;
}
if (grub_strcmp (args[*argn + 1], "-ge") == 0)
{
update_val (grub_strtosl (args[*argn], 0, 0)
>= grub_strtosl (args[*argn + 2], 0, 0));
(*argn) += 3;
continue;
}
if (grub_strcmp (args[*argn + 1], "-gt") == 0)
{
update_val (grub_strtosl (args[*argn], 0, 0)
> grub_strtosl (args[*argn + 2], 0, 0));
(*argn) += 3;
continue;
}
if (grub_strcmp (args[*argn + 1], "-le") == 0)
{
update_val (grub_strtosl (args[*argn], 0, 0)
<= grub_strtosl (args[*argn + 2], 0, 0));
(*argn) += 3;
continue;
}
if (grub_strcmp (args[*argn + 1], "-lt") == 0)
{
update_val (grub_strtosl (args[*argn], 0, 0)
< grub_strtosl (args[*argn + 2], 0, 0));
(*argn) += 3;
continue;
}
if (grub_strcmp (args[*argn + 1], "-ne") == 0)
{
update_val (grub_strtosl (args[*argn], 0, 0)
!= grub_strtosl (args[*argn + 2], 0, 0));
(*argn) += 3;
continue;
}
/* GRUB extension: compare numbers skipping prefixes.
Useful for comparing versions. E.g. vmlinuz-2 -plt vmlinuz-11. */
if (grub_strcmp (args[*argn + 1], "-pgt") == 0
|| grub_strcmp (args[*argn + 1], "-plt") == 0)
{
int i;
/* Skip common prefix. */
for (i = 0; args[*argn][i] == args[*argn + 2][i]
&& args[*argn][i]; i++);
/* Go the digits back. */
i--;
while (grub_isdigit (args[*argn][i]) && i > 0)
i--;
i++;
if (grub_strcmp (args[*argn + 1], "-pgt") == 0)
update_val (grub_strtoul (args[*argn] + i, 0, 0)
> grub_strtoul (args[*argn + 2] + i, 0, 0));
else
update_val (grub_strtoul (args[*argn] + i, 0, 0)
< grub_strtoul (args[*argn + 2] + i, 0, 0));
(*argn) += 3;
continue;
}
/* -nt and -ot tests. GRUB extension: when doing -?t<bias> bias
will be added to the first mtime. */
if (grub_memcmp (args[*argn + 1], "-nt", 3) == 0
|| grub_memcmp (args[*argn + 1], "-ot", 3) == 0)
{
struct grub_dirhook_info file1;
int file1exists;
int bias = 0;
/* Fetch fileinfo. */
get_fileinfo (args[*argn]);
file1 = file_info;
file1exists = file_exists;
get_fileinfo (args[*argn + 2]);
if (args[*argn + 1][3])
bias = grub_strtosl (args[*argn + 1] + 3, 0, 0);
if (grub_memcmp (args[*argn + 1], "-nt", 3) == 0)
update_val ((file1exists && ! file_exists)
|| (file1.mtimeset && file_info.mtimeset
&& file1.mtime + bias > file_info.mtime));
else
update_val ((! file1exists && file_exists)
|| (file1.mtimeset && file_info.mtimeset
&& file1.mtime + bias < file_info.mtime));
(*argn) += 3;
continue;
}
}
/* Two-argument tests. */
if (*argn + 1 < argc)
{
/* File tests. */
if (grub_strcmp (args[*argn], "-d") == 0)
{
get_fileinfo (args[*argn + 1]);
update_val (file_exists && file_info.dir);
(*argn) += 2;
return ret;
}
if (grub_strcmp (args[*argn], "-e") == 0)
{
get_fileinfo (args[*argn + 1]);
update_val (file_exists);
(*argn) += 2;
return ret;
}
if (grub_strcmp (args[*argn], "-f") == 0)
{
get_fileinfo (args[*argn + 1]);
/* FIXME: check for other types. */
update_val (file_exists && ! file_info.dir);
(*argn) += 2;
return ret;
}
if (grub_strcmp (args[*argn], "-s") == 0)
{
grub_file_t file;
file = grub_file_open (args[*argn + 1]);
update_val (file && (grub_file_size (file) != 0));
if (file)
grub_file_close (file);
grub_errno = GRUB_ERR_NONE;
(*argn) += 2;
return ret;
}
/* String tests. */
if (grub_strcmp (args[*argn], "-n") == 0)
{
update_val (args[*argn + 1][0]);
(*argn) += 2;
continue;
}
if (grub_strcmp (args[*argn], "-z") == 0)
{
update_val (! args[*argn + 1][0]);
(*argn) += 2;
continue;
}
}
/* Special modifiers. */
/* End of expression. return to parent. */
if (grub_strcmp (args[*argn], ")") == 0)
{
(*argn)++;
return ret;
}
/* Recursively invoke if parenthesis. */
if (grub_strcmp (args[*argn], "(") == 0)
{
(*argn)++;
update_val (test_parse (args, argn, argc));
continue;
}
if (grub_strcmp (args[*argn], "!") == 0)
{
invert = ! invert;
(*argn)++;
continue;
}
if (grub_strcmp (args[*argn], "-a") == 0)
{
/* If current value is 0 second value is to be discarded. */
discard = ! ret;
(*argn)++;
continue;
}
if (grub_strcmp (args[*argn], "-o") == 0)
{
/* If current value is 1 second value is to be discarded. */
discard = ret;
(*argn)++;
continue;
}
/* No test found. Interpret if as just a string. */
update_val (args[*argn][0]);
(*argn)++;
}
return ret;
}
static grub_err_t
grub_cmd_test (grub_command_t cmd __attribute__ ((unused)),
int argc, char **args)
{
int argn = 0;
if (argc >= 1 && grub_strcmp (args[argc - 1], "]") == 0)
argc--;
return test_parse (args, &argn, argc) ? GRUB_ERR_NONE
: grub_error (GRUB_ERR_TEST_FAILURE, "false");
}
static grub_command_t cmd_1, cmd_2;
GRUB_MOD_INIT(test)
{
cmd_1 = grub_register_command ("[", grub_cmd_test,
"[ EXPRESSION ]", "Evaluate an expression");
cmd_2 = grub_register_command ("test", grub_cmd_test,
"test EXPRESSION", "Evaluate an expression");
}
GRUB_MOD_FINI(test)
{
grub_unregister_command (cmd_1);
grub_unregister_command (cmd_2);
}