busybox/coreutils/test.c
Rob Landley ecb29573e9 "Jordan Crouse" <jordan.crouse@amd.com> says:
The following patch makes coreutils/test.c act fail gracefully if getgroups() 
returns a -1.  This fixes a problem on the One Laptop Per Child ROM image
whereby we were getting odd Memory exhausted messages for '[' and 'test'.

Found by Mitch Bradley <wmb@firmworks.com>
(Tweaked by Rob: no need to initialize a static to NULL, or realloc something
that's only allocated when it's NULL.)
2006-08-22 23:40:28 +00:00

584 lines
11 KiB
C

/* 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.
*
* 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 "busybox.h"
#include <unistd.h>
#include <ctype.h>
#include <errno.h>
#include <string.h>
#include <setjmp.h>
/* 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
};
enum token_types {
UNOP,
BINOP,
BUNOP,
BBINOP,
PAREN
};
static const struct t_op {
const char *op_text;
short 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}, {
0, 0, 0}
};
#ifdef CONFIG_FEATURE_TEST_64
typedef int64_t arith_t;
#else
typedef int arith_t;
#endif
static char **t_wp;
static struct t_op const *t_wp_op;
static gid_t *group_array;
static int ngroups;
static enum token t_lex(char *s);
static arith_t oexpr(enum token n);
static arith_t aexpr(enum token n);
static arith_t nexpr(enum token n);
static int binop(void);
static arith_t primary(enum token n);
static int filstat(char *nm, enum token mode);
static arith_t getn(const char *s);
static int newerf(const char *f1, const char *f2);
static int olderf(const char *f1, const char *f2);
static int equalf(const char *f1, const char *f2);
static int test_eaccess(char *path, int mode);
static int is_a_group_member(gid_t gid);
static void initialize_group_array(void);
static jmp_buf leaving;
int bb_test(int argc, char **argv)
{
int res;
if (strcmp(argv[0], "[") == 0) {
if (strcmp(argv[--argc], "]")) {
bb_error_msg("missing ]");
return 2;
}
argv[argc] = NULL;
} else if (strcmp(argv[0], "[[") == 0) {
if (strcmp(argv[--argc], "]]")) {
bb_error_msg("missing ]]");
return 2;
}
argv[argc] = NULL;
}
res = setjmp(leaving);
if (res)
return res;
/* 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;
/* Implement special cases from POSIX.2, section 4.62.4 */
switch (argc) {
case 1:
return 1;
case 2:
return *argv[1] == '\0';
case 3:
if (argv[1][0] == '!' && argv[1][1] == '\0') {
return *argv[2] != '\0';
}
break;
case 4:
if (argv[1][0] != '!' || argv[1][1] != '\0') {
if (t_lex(argv[2]), t_wp_op && t_wp_op->op_type == BINOP) {
t_wp = &argv[1];
return binop() == 0;
}
}
break;
case 5:
if (argv[1][0] == '!' && argv[1][1] == '\0') {
if (t_lex(argv[3]), t_wp_op && t_wp_op->op_type == BINOP) {
t_wp = &argv[2];
return binop() != 0;
}
}
break;
}
t_wp = &argv[1];
res = !oexpr(t_lex(*t_wp));
if (*t_wp != NULL && *++t_wp != NULL) {
bb_error_msg("%s: unknown operand", *t_wp);
return 2;
}
return res;
}
static void syntax(const char *op, const char *msg)
{
if (op && *op) {
bb_error_msg("%s: %s", op, msg);
} else {
bb_error_msg("%s", msg);
}
longjmp(leaving, 2);
}
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 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 nexpr(enum token n)
{
if (n == UNOT)
return !nexpr(t_lex(*++t_wp));
return primary(n);
}
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");
switch (n) {
case STREZ:
return strlen(*t_wp) == 0;
case STRNZ:
return strlen(*t_wp) != 0;
case FILTT:
return isatty(getn(*t_wp));
default:
return filstat(*t_wp, n);
}
}
if (t_lex(t_wp[1]), t_wp_op && t_wp_op->op_type == BINOP) {
return binop();
}
return strlen(*t_wp) > 0;
}
static int binop(void)
{
const char *opnd1, *opnd2;
struct t_op const *op;
opnd1 = *t_wp;
(void) t_lex(*++t_wp);
op = t_wp_op;
if ((opnd2 = *++t_wp) == (char *) 0)
syntax(op->op_text, "argument expected");
switch (op->op_num) {
case STREQ:
return strcmp(opnd1, opnd2) == 0;
case STRNE:
return strcmp(opnd1, opnd2) != 0;
case STRLT:
return strcmp(opnd1, opnd2) < 0;
case STRGT:
return strcmp(opnd1, opnd2) > 0;
case INTEQ:
return getn(opnd1) == getn(opnd2);
case INTNE:
return getn(opnd1) != getn(opnd2);
case INTGE:
return getn(opnd1) >= getn(opnd2);
case INTGT:
return getn(opnd1) > getn(opnd2);
case INTLE:
return getn(opnd1) <= getn(opnd2);
case INTLT:
return getn(opnd1) < getn(opnd2);
case FILNT:
return newerf(opnd1, opnd2);
case FILOT:
return olderf(opnd1, opnd2);
case FILEQ:
return equalf(opnd1, opnd2);
}
/* NOTREACHED */
return 1;
}
static int filstat(char *nm, enum token mode)
{
struct stat s;
unsigned int i;
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;
switch (mode) {
case FILRD:
return test_eaccess(nm, R_OK) == 0;
case FILWR:
return test_eaccess(nm, W_OK) == 0;
case FILEX:
return test_eaccess(nm, X_OK) == 0;
case FILEXIST:
return 1;
case FILREG:
i = S_IFREG;
goto filetype;
case FILDIR:
i = S_IFDIR;
goto filetype;
case FILCDEV:
i = S_IFCHR;
goto filetype;
case FILBDEV:
i = S_IFBLK;
goto filetype;
case FILFIFO:
#ifdef S_IFIFO
i = S_IFIFO;
goto filetype;
#else
return 0;
#endif
case FILSOCK:
#ifdef S_IFSOCK
i = S_IFSOCK;
goto filetype;
#else
return 0;
#endif
case FILSUID:
i = S_ISUID;
goto filebit;
case FILSGID:
i = S_ISGID;
goto filebit;
case FILSTCK:
i = S_ISVTX;
goto filebit;
case FILGZ:
return s.st_size > 0L;
case FILUID:
return s.st_uid == geteuid();
case FILGID:
return s.st_gid == getegid();
default:
return 1;
}
filetype:
return ((s.st_mode & S_IFMT) == i);
filebit:
return ((s.st_mode & i) != 0);
}
static enum token t_lex(char *s)
{
struct t_op const *op = ops;
if (s == 0) {
t_wp_op = (struct t_op *) 0;
return EOI;
}
while (op->op_text) {
if (strcmp(s, op->op_text) == 0) {
t_wp_op = op;
return op->op_num;
}
op++;
}
t_wp_op = (struct t_op *) 0;
return OPERAND;
}
/* atoi with error detection */
static arith_t getn(const char *s)
{
char *p;
#ifdef CONFIG_FEATURE_TEST_64
long long r;
#else
long r;
#endif
errno = 0;
#ifdef CONFIG_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;
}
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);
}
/* 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 void initialize_group_array(void)
{
ngroups = getgroups(0, NULL);
if (ngroups > 0) {
group_array = xmalloc(ngroups * sizeof(gid_t));
getgroups(ngroups, group_array);
}
}
/* Return non-zero if GID is one that we have in our groups list. */
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);
}
/* applet entry point */
int test_main(int argc, char **argv)
{
exit(bb_test(argc, argv));
}