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hush/coreutils/test.c

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/* vi: set sw=4 ts=4: */
/*
* test implementation for busybox
*
* Copyright (c) by a whole pile of folks:
*
* test(1); version 7-like -- author Erik Baalbergen
* modified by Eric Gisin to be used as built-in.
* modified by Arnold Robbins to add SVR3 compatibility
* (-x -c -b -p -u -g -k) plus Korn's -L -nt -ot -ef and new -S (socket).
* modified by J.T. Conklin for NetBSD.
* modified by Herbert Xu to be used as built-in in ash.
* modified by Erik Andersen <andersen@codepoet.org> to be used
* in busybox.
* modified by Bernhard Fischer to be useable (i.e. a bit less bloaty).
*
* Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
*
* Original copyright notice states:
* "This program is in the Public Domain."
*/
#include "libbb.h"
#include <setjmp.h>
/* This is a NOFORK applet. Be very careful! */
/* test_main() is called from shells, and we need to be extra careful here.
* This is true regardless of PREFER_APPLETS and STANDALONE_SHELL
* state. */
/* test(1) accepts the following grammar:
oexpr ::= aexpr | aexpr "-o" oexpr ;
aexpr ::= nexpr | nexpr "-a" aexpr ;
nexpr ::= primary | "!" primary
primary ::= unary-operator operand
| operand binary-operator operand
| operand
| "(" oexpr ")"
;
unary-operator ::= "-r"|"-w"|"-x"|"-f"|"-d"|"-c"|"-b"|"-p"|
"-u"|"-g"|"-k"|"-s"|"-t"|"-z"|"-n"|"-o"|"-O"|"-G"|"-L"|"-S";
binary-operator ::= "="|"=="|"!="|"-eq"|"-ne"|"-ge"|"-gt"|"-le"|"-lt"|
"-nt"|"-ot"|"-ef";
operand ::= <any legal UNIX file name>
*/
enum token {
EOI,
FILRD,
FILWR,
FILEX,
FILEXIST,
FILREG,
FILDIR,
FILCDEV,
FILBDEV,
FILFIFO,
FILSOCK,
FILSYM,
FILGZ,
FILTT,
FILSUID,
FILSGID,
FILSTCK,
FILNT,
FILOT,
FILEQ,
FILUID,
FILGID,
STREZ,
STRNZ,
STREQ,
STRNE,
STRLT,
STRGT,
INTEQ,
INTNE,
INTGE,
INTGT,
INTLE,
INTLT,
UNOT,
BAND,
BOR,
LPAREN,
RPAREN,
OPERAND
};
#define is_int_op(a) (((unsigned char)((a) - INTEQ)) <= 5)
#define is_str_op(a) (((unsigned char)((a) - STREZ)) <= 5)
#define is_file_op(a) (((unsigned char)((a) - FILNT)) <= 2)
#define is_file_access(a) (((unsigned char)((a) - FILRD)) <= 2)
#define is_file_type(a) (((unsigned char)((a) - FILREG)) <= 5)
#define is_file_bit(a) (((unsigned char)((a) - FILSUID)) <= 2)
enum token_types {
UNOP,
BINOP,
BUNOP,
BBINOP,
PAREN
};
static const struct t_op {
char op_text[4];
unsigned char op_num, op_type;
} ops[] = {
{ "-r", FILRD , UNOP },
{ "-w", FILWR , UNOP },
{ "-x", FILEX , UNOP },
{ "-e", FILEXIST, UNOP },
{ "-f", FILREG , UNOP },
{ "-d", FILDIR , UNOP },
{ "-c", FILCDEV , UNOP },
{ "-b", FILBDEV , UNOP },
{ "-p", FILFIFO , UNOP },
{ "-u", FILSUID , UNOP },
{ "-g", FILSGID , UNOP },
{ "-k", FILSTCK , UNOP },
{ "-s", FILGZ , UNOP },
{ "-t", FILTT , UNOP },
{ "-z", STREZ , UNOP },
{ "-n", STRNZ , UNOP },
{ "-h", FILSYM , UNOP }, /* for backwards compat */
{ "-O" , FILUID , UNOP },
{ "-G" , FILGID , UNOP },
{ "-L" , FILSYM , UNOP },
{ "-S" , FILSOCK, UNOP },
{ "=" , STREQ , BINOP },
{ "==" , STREQ , BINOP },
{ "!=" , STRNE , BINOP },
{ "<" , STRLT , BINOP },
{ ">" , STRGT , BINOP },
{ "-eq", INTEQ , BINOP },
{ "-ne", INTNE , BINOP },
{ "-ge", INTGE , BINOP },
{ "-gt", INTGT , BINOP },
{ "-le", INTLE , BINOP },
{ "-lt", INTLT , BINOP },
{ "-nt", FILNT , BINOP },
{ "-ot", FILOT , BINOP },
{ "-ef", FILEQ , BINOP },
{ "!" , UNOT , BUNOP },
{ "-a" , BAND , BBINOP },
{ "-o" , BOR , BBINOP },
{ "(" , LPAREN , PAREN },
{ ")" , RPAREN , PAREN },
};
#if ENABLE_FEATURE_TEST_64
typedef int64_t arith_t;
#else
typedef int arith_t;
#endif
/* We try to minimize both static and stack usage. */
struct statics {
char **t_wp;
const struct t_op *t_wp_op;
gid_t *group_array;
int ngroups;
jmp_buf leaving;
};
/* Make it reside in writable memory, yet make compiler understand
* that it is not going to change. */
static struct statics *const ptr_to_statics __attribute__ ((section (".data")));
#define S (*ptr_to_statics)
#define t_wp (S.t_wp )
#define t_wp_op (S.t_wp_op )
#define group_array (S.group_array )
#define ngroups (S.ngroups )
#define leaving (S.leaving )
#define INIT_S() do { \
(*(struct statics**)&ptr_to_statics) = xzalloc(sizeof(S)); \
barrier(); \
} while (0)
#define DEINIT_S() do { \
free(ptr_to_statics); \
} while (0)
static arith_t primary(enum token n);
static void syntax(const char *op, const char *msg) ATTRIBUTE_NORETURN;
static void syntax(const char *op, const char *msg)
{
if (op && *op) {
bb_error_msg("%s: %s", op, msg);
} else {
bb_error_msg("%s: %s"+4, msg);
}
longjmp(leaving, 2);
}
/* atoi with error detection */
//XXX: FIXME: duplicate of existing libbb function?
static arith_t getn(const char *s)
{
char *p;
#if ENABLE_FEATURE_TEST_64
long long r;
#else
long r;
#endif
errno = 0;
#if ENABLE_FEATURE_TEST_64
r = strtoll(s, &p, 10);
#else
r = strtol(s, &p, 10);
#endif
if (errno != 0)
syntax(s, "out of range");
if (*(skip_whitespace(p)))
syntax(s, "bad number");
return r;
}
/* UNUSED
static int newerf(const char *f1, const char *f2)
{
struct stat b1, b2;
return (stat(f1, &b1) == 0 &&
stat(f2, &b2) == 0 && b1.st_mtime > b2.st_mtime);
}
static int olderf(const char *f1, const char *f2)
{
struct stat b1, b2;
return (stat(f1, &b1) == 0 &&
stat(f2, &b2) == 0 && b1.st_mtime < b2.st_mtime);
}
static int equalf(const char *f1, const char *f2)
{
struct stat b1, b2;
return (stat(f1, &b1) == 0 &&
stat(f2, &b2) == 0 &&
b1.st_dev == b2.st_dev && b1.st_ino == b2.st_ino);
}
*/
static enum token t_lex(char *s)
{
const struct t_op *op;
t_wp_op = NULL;
if (s == NULL) {
return EOI;
}
op = ops;
do {
if (strcmp(s, op->op_text) == 0) {
t_wp_op = op;
return op->op_num;
}
op++;
} while (op < ops + ARRAY_SIZE(ops));
return OPERAND;
}
static int binop(void)
{
const char *opnd1, *opnd2;
struct t_op const *op;
arith_t val1, val2;
opnd1 = *t_wp;
(void) t_lex(*++t_wp);
op = t_wp_op;
opnd2 = *++t_wp;
if (opnd2 == NULL)
syntax(op->op_text, "argument expected");
if (is_int_op(op->op_num)) {
val1 = getn(opnd1);
val2 = getn(opnd2);
if (op->op_num == INTEQ)
return val1 == val2;
if (op->op_num == INTNE)
return val1 != val2;
if (op->op_num == INTGE)
return val1 >= val2;
if (op->op_num == INTGT)
return val1 > val2;
if (op->op_num == INTLE)
return val1 <= val2;
if (op->op_num == INTLT)
return val1 < val2;
}
if (is_str_op(op->op_num)) {
val1 = strcmp(opnd1, opnd2);
if (op->op_num == STREQ)
return val1 == 0;
if (op->op_num == STRNE)
return val1 != 0;
if (op->op_num == STRLT)
return val1 < 0;
if (op->op_num == STRGT)
return val1 > 0;
}
/* We are sure that these three are by now the only binops we didn't check
* yet, so we do not check if the class is correct:
*/
/* if (is_file_op(op->op_num)) */
{
struct stat b1, b2;
if (stat(opnd1, &b1) || stat(opnd2, &b2))
return 0; /* false, since at least one stat failed */
if (op->op_num == FILNT)
return b1.st_mtime > b2.st_mtime;
if (op->op_num == FILOT)
return b1.st_mtime < b2.st_mtime;
if (op->op_num == FILEQ)
return b1.st_dev == b2.st_dev && b1.st_ino == b2.st_ino;
}
return 1; /* NOTREACHED */
}
static void initialize_group_array(void)
{
ngroups = getgroups(0, NULL);
if (ngroups > 0) {
/* FIXME: ash tries so hard to not die on OOM,
* and we spoil it with just one xrealloc here */
/* We realloc, because test_main can be entered repeatedly by shell.
* Testcase (ash): 'while true; do test -x some_file; done'
* and watch top. (some_file must have owner != you) */
group_array = xrealloc(group_array, ngroups * sizeof(gid_t));
getgroups(ngroups, group_array);
}
}
/* Return non-zero if GID is one that we have in our groups list. */
//XXX: FIXME: duplicate of existing libbb function?
// see toplevel TODO file:
// possible code duplication ingroup() and is_a_group_member()
static int is_a_group_member(gid_t gid)
{
int i;
/* Short-circuit if possible, maybe saving a call to getgroups(). */
if (gid == getgid() || gid == getegid())
return 1;
if (ngroups == 0)
initialize_group_array();
/* Search through the list looking for GID. */
for (i = 0; i < ngroups; i++)
if (gid == group_array[i])
return 1;
return 0;
}
/* Do the same thing access(2) does, but use the effective uid and gid,
and don't make the mistake of telling root that any file is
executable. */
static int test_eaccess(char *path, int mode)
{
struct stat st;
unsigned int euid = geteuid();
if (stat(path, &st) < 0)
return -1;
if (euid == 0) {
/* Root can read or write any file. */
if (mode != X_OK)
return 0;
/* Root can execute any file that has any one of the execute
bits set. */
if (st.st_mode & (S_IXUSR | S_IXGRP | S_IXOTH))
return 0;
}
if (st.st_uid == euid) /* owner */
mode <<= 6;
else if (is_a_group_member(st.st_gid))
mode <<= 3;
if (st.st_mode & mode)
return 0;
return -1;
}
static int filstat(char *nm, enum token mode)
{
struct stat s;
int i = i; /* gcc 3.x thinks it can be used uninitialized */
if (mode == FILSYM) {
#ifdef S_IFLNK
if (lstat(nm, &s) == 0) {
i = S_IFLNK;
goto filetype;
}
#endif
return 0;
}
if (stat(nm, &s) != 0)
return 0;
if (mode == FILEXIST)
return 1;
if (is_file_access(mode)) {
if (mode == FILRD)
i = R_OK;
if (mode == FILWR)
i = W_OK;
if (mode == FILEX)
i = X_OK;
return test_eaccess(nm, i) == 0;
}
if (is_file_type(mode)) {
if (mode == FILREG)
i = S_IFREG;
if (mode == FILDIR)
i = S_IFDIR;
if (mode == FILCDEV)
i = S_IFCHR;
if (mode == FILBDEV)
i = S_IFBLK;
if (mode == FILFIFO) {
#ifdef S_IFIFO
i = S_IFIFO;
#else
return 0;
#endif
}
if (mode == FILSOCK) {
#ifdef S_IFSOCK
i = S_IFSOCK;
#else
return 0;
#endif
}
filetype:
return ((s.st_mode & S_IFMT) == i);
}
if (is_file_bit(mode)) {
if (mode == FILSUID)
i = S_ISUID;
if (mode == FILSGID)
i = S_ISGID;
if (mode == FILSTCK)
i = S_ISVTX;
return ((s.st_mode & i) != 0);
}
if (mode == FILGZ)
return s.st_size > 0L;
if (mode == FILUID)
return s.st_uid == geteuid();
if (mode == FILGID)
return s.st_gid == getegid();
return 1; /* NOTREACHED */
}
static arith_t nexpr(enum token n)
{
if (n == UNOT)
return !nexpr(t_lex(*++t_wp));
return primary(n);
}
static arith_t aexpr(enum token n)
{
arith_t res;
res = nexpr(n);
if (t_lex(*++t_wp) == BAND)
return aexpr(t_lex(*++t_wp)) && res;
t_wp--;
return res;
}
static arith_t oexpr(enum token n)
{
arith_t res;
res = aexpr(n);
if (t_lex(*++t_wp) == BOR) {
return oexpr(t_lex(*++t_wp)) || res;
}
t_wp--;
return res;
}
static arith_t primary(enum token n)
{
arith_t res;
if (n == EOI) {
syntax(NULL, "argument expected");
}
if (n == LPAREN) {
res = oexpr(t_lex(*++t_wp));
if (t_lex(*++t_wp) != RPAREN)
syntax(NULL, "closing paren expected");
return res;
}
if (t_wp_op && t_wp_op->op_type == UNOP) {
/* unary expression */
if (*++t_wp == NULL)
syntax(t_wp_op->op_text, "argument expected");
if (n == STREZ)
return t_wp[0][0] == '\0';
if (n == STRNZ)
return t_wp[0][0] != '\0';
if (n == FILTT)
return isatty(getn(*t_wp));
return filstat(*t_wp, n);
}
t_lex(t_wp[1]);
if (t_wp_op && t_wp_op->op_type == BINOP) {
return binop();
}
return t_wp[0][0] != '\0';
}
int test_main(int argc, char **argv)
{
int res;
const char *arg0;
bool negate = 0;
arg0 = bb_basename(argv[0]);
if (arg0[0] == '[') {
--argc;
if (!arg0[1]) { /* "[" ? */
if (NOT_LONE_CHAR(argv[argc], ']')) {
bb_error_msg("missing ]");
return 2;
}
} else { /* assuming "[[" */
if (strcmp(argv[argc], "]]") != 0) {
bb_error_msg("missing ]]");
return 2;
}
}
argv[argc] = NULL;
}
/* We must do DEINIT_S() prior to returning */
INIT_S();
res = setjmp(leaving);
if (res)
goto ret;
/* resetting ngroups is probably unnecessary. it will
* force a new call to getgroups(), which prevents using
* group data fetched during a previous call. but the
* only way the group data could be stale is if there's
* been an intervening call to setgroups(), and this
* isn't likely in the case of a shell. paranoia
* prevails...
*/
ngroups = 0;
//argc--;
argv++;
/* Implement special cases from POSIX.2, section 4.62.4 */
if (!argv[0]) { /* "test" */
res = 1;
goto ret;
}
if (LONE_CHAR(argv[0], '!') && argv[1]) {
negate = 1;
//argc--;
argv++;
}
if (!argv[1]) { /* "test [!] arg" */
res = (*argv[0] == '\0');
goto ret;
}
if (argv[2] && !argv[3]) {
t_lex(argv[1]);
if (t_wp_op && t_wp_op->op_type == BINOP) {
/* "test [!] arg1 <binary_op> arg2" */
t_wp = &argv[0];
res = (binop() == 0);
goto ret;
}
}
/* Some complex expression. Undo '!' removal */
if (negate) {
negate = 0;
//argc++;
argv--;
}
t_wp = &argv[0];
res = !oexpr(t_lex(*t_wp));
if (*t_wp != NULL && *++t_wp != NULL) {
bb_error_msg("%s: unknown operand", *t_wp);
res = 2;
}
ret:
DEINIT_S();
return negate ? !res : res;
}
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