NetBSD/bin/test/test.c
kre df8e475ae0 Allow SMALL (and TINY) builds of test (for SMALL/TINY builds of sh)
which support only the defined modes of operation of test, to allow
the version of sh on small install media be kept as small as possible.
2018-09-13 22:00:58 +00:00

905 lines
21 KiB
C

/* $NetBSD: test.c,v 1.43 2018/09/13 22:00:58 kre Exp $ */
/*
* 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.
*
* This program is in the Public Domain.
*/
#include <sys/cdefs.h>
#ifndef lint
__RCSID("$NetBSD: test.c,v 1.43 2018/09/13 22:00:58 kre Exp $");
#endif
#include <sys/stat.h>
#include <sys/types.h>
#include <ctype.h>
#include <err.h>
#include <errno.h>
#include <limits.h>
#include <locale.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <stdarg.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
#ifndef SMALL
,
BUNOP,
BBINOP,
PAREN
#endif
};
struct t_op {
const char *op_text;
short op_num, op_type;
};
static const struct t_op cop[] = {
#ifndef SMALL
{"!", UNOT, BUNOP},
{"(", LPAREN, PAREN},
{")", RPAREN, PAREN},
#endif
{"<", STRLT, BINOP},
{"=", STREQ, BINOP},
{">", STRGT, BINOP},
};
static const struct t_op cop2[] = {
{"!=", STRNE, BINOP},
};
static const struct t_op mop3[] = {
{"ef", FILEQ, BINOP},
{"eq", INTEQ, BINOP},
{"ge", INTGE, BINOP},
{"gt", INTGT, BINOP},
{"le", INTLE, BINOP},
{"lt", INTLT, BINOP},
{"ne", INTNE, BINOP},
{"nt", FILNT, BINOP},
{"ot", FILOT, BINOP},
};
static const struct t_op mop2[] = {
{"G", FILGID, UNOP},
{"L", FILSYM, UNOP},
{"O", FILUID, UNOP},
{"S", FILSOCK,UNOP},
#ifndef SMALL
{"a", BAND, BBINOP},
#endif
{"b", FILBDEV,UNOP},
{"c", FILCDEV,UNOP},
{"d", FILDIR, UNOP},
{"e", FILEXIST,UNOP},
{"f", FILREG, UNOP},
{"g", FILSGID,UNOP},
{"h", FILSYM, UNOP}, /* for backwards compat */
{"k", FILSTCK,UNOP},
{"n", STRNZ, UNOP},
#ifndef SMALL
{"o", BOR, BBINOP},
#endif
{"p", FILFIFO,UNOP},
{"r", FILRD, UNOP},
{"s", FILGZ, UNOP},
{"t", FILTT, UNOP},
{"u", FILSUID,UNOP},
{"w", FILWR, UNOP},
{"x", FILEX, UNOP},
{"z", STREZ, UNOP},
};
#ifndef SMALL
static char **t_wp;
static struct t_op const *t_wp_op;
#endif
#ifndef SMALL
__dead static void syntax(const char *, const char *);
static int oexpr(enum token);
static int aexpr(enum token);
static int nexpr(enum token);
static int primary(enum token);
static int binop(void);
static enum token t_lex(char *);
static int isoperand(void);
#endif
static struct t_op const *findop(const char *);
static int perform_unop(enum token, const char *);
static int perform_binop(enum token, const char *, const char *);
static int test_access(struct stat *, mode_t);
static int filstat(const char *, enum token);
static long long getn(const char *);
static int newerf(const char *, const char *);
static int olderf(const char *, const char *);
static int equalf(const char *, const char *);
static int one_arg(const char *);
static int two_arg(const char *, const char *);
static int three_arg(const char *, const char *, const char *);
static int four_arg(const char *, const char *, const char *, const char *);
#if defined(SHELL)
extern void error(const char *, ...) __dead __printflike(1, 2);
extern void *ckmalloc(size_t);
#else
static void error(const char *, ...) __dead __printflike(1, 2);
static void
error(const char *msg, ...)
{
va_list ap;
va_start(ap, msg);
verrx(2, msg, ap);
/*NOTREACHED*/
va_end(ap);
}
static void *ckmalloc(size_t);
static void *
ckmalloc(size_t nbytes)
{
void *p = malloc(nbytes);
if (!p)
error("Not enough memory!");
return p;
}
#endif
#ifdef SHELL
int testcmd(int, char **);
int
testcmd(int argc, char **argv)
#else
int
main(int argc, char *argv[])
#endif
{
int res;
const char *argv0;
#ifdef SHELL
argv0 = argv[0];
#else
setprogname(argv[0]);
(void)setlocale(LC_ALL, "");
argv0 = getprogname();
#endif
if (strcmp(argv0, "[") == 0) {
if (strcmp(argv[--argc], "]"))
error("missing ]");
argv[argc] = NULL;
}
/*
* POSIX defines operations of test for up to 4 args
* (depending upon what the args are in some cases)
*
* arg count does not include the command name, (but argc does)
* nor the closing ']' when the command was '[' (removed above)
*
* None of the following allow -a or -o as an operator (those
* only apply in the evaluation of unspeicified expressions)
*
* Note that the xxx_arg() functions return "shell" true/false
* (0 == true, 1 == false) or -1 for "unspecified case"
*
* Other functions return C true/false (1 == true, 0 == false)
*
* Hence we simply return the result from xxx_arg(), but
* invert the result of oexpr() below before returning it.
*/
switch (argc - 1) {
case -1: /* impossible, but never mind */
case 0: /* test $a where a='' false */
return 1;
case 1: /* test "$a" */
return one_arg(argv[1]); /* always works */
case 2: /* test op "$a" */
res = two_arg(argv[1], argv[2]);
if (res >= 0)
return res;
break;
case 3: /* test "$a" op "$b" or test ! op "$a" */
res = three_arg(argv[1], argv[2], argv[3]);
if (res >= 0)
return res;
break;
case 4: /* test ! "$a" op "$b" or test ( op "$a" ) */
res = four_arg(argv[1], argv[2], argv[3], argv[4]);
if (res >= 0)
return res;
break;
default:
break;
}
/*
* All other cases produce unspecified results
* (including cases above with small arg counts where the
* args are not what was expected to be seen)
*
* We fall back to the old method, of attempting to parse
* the expr (highly ambiguous as there is no distinction between
* operators and operands that happen to look like operators)
*/
#ifdef SMALL
error("SMALL test, no fallback usage");
#else
t_wp = &argv[1];
res = !oexpr(t_lex(*t_wp));
if (*t_wp != NULL && *++t_wp != NULL)
syntax(*t_wp, "unexpected operator");
return res;
#endif
}
#ifndef SMALL
static void
syntax(const char *op, const char *msg)
{
if (op && *op)
error("%s: %s", op, msg);
else
error("%s", msg);
}
#endif
static int
one_arg(const char *arg)
{
/*
* True (exit 0, so false...) if arg is not a null string
* False (so exit 1, so true) if it is.
*/
return *arg == '\0';
}
static int
two_arg(const char *a1, const char *a2)
{
static struct t_op const *op;
if (a1[0] == '!' && a1[1] == 0)
return !one_arg(a2);
op = findop(a1);
if (op != NULL && op->op_type == UNOP)
return !perform_unop(op->op_num, a2);
#ifndef TINY
/*
* an extension, but as we've entered the realm of the unspecified
* we're allowed... test ( $a ) where a=''
*/
if (a1[0] == '(' && a2[0] == ')' && (a1[1] | a2[1]) == 0)
return 1;
#endif
return -1;
}
static int
three_arg(const char *a1, const char *a2, const char *a3)
{
static struct t_op const *op;
int res;
op = findop(a2);
if (op != NULL && op->op_type == BINOP)
return !perform_binop(op->op_num, a1, a3);
if (a1[1] != '\0')
return -1;
if (a1[0] == '!') {
res = two_arg(a2, a3);
if (res >= 0)
res = !res;
return res;
}
#ifndef TINY
if (a1[0] == '(' && a3[0] == ')' && a3[1] == '\0')
return one_arg(a2);
#endif
return -1;
}
static int
four_arg(const char *a1, const char *a2, const char *a3, const char *a4)
{
int res;
if (a1[1] != '\0')
return -1;
if (a1[0] == '!') {
res = three_arg(a2, a3, a4);
if (res >= 0)
res = !res;
return res;
}
#ifndef TINY
if (a1[0] == '(' && a4[0] == ')' && a4[1] == '\0')
return two_arg(a2, a3);
#endif
return -1;
}
#ifndef SMALL
static int
oexpr(enum token n)
{
int res;
res = aexpr(n);
if (*t_wp == NULL)
return res;
if (t_lex(*++t_wp) == BOR)
return oexpr(t_lex(*++t_wp)) || res;
t_wp--;
return res;
}
static int
aexpr(enum token n)
{
int res;
res = nexpr(n);
if (*t_wp == NULL)
return res;
if (t_lex(*++t_wp) == BAND)
return aexpr(t_lex(*++t_wp)) && res;
t_wp--;
return res;
}
static int
nexpr(enum token n)
{
if (n == UNOT)
return !nexpr(t_lex(*++t_wp));
return primary(n);
}
static int
primary(enum token n)
{
enum token nn;
int res;
if (n == EOI)
return 0; /* missing expression */
if (n == LPAREN) {
if ((nn = t_lex(*++t_wp)) == RPAREN)
return 0; /* missing expression */
res = oexpr(nn);
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");
return perform_unop(n, *t_wp);
}
if (t_lex(t_wp[1]), t_wp_op && t_wp_op->op_type == BINOP) {
return binop();
}
return strlen(*t_wp) > 0;
}
#endif /* !SMALL */
static int
perform_unop(enum token n, const char *opnd)
{
switch (n) {
case STREZ:
return strlen(opnd) == 0;
case STRNZ:
return strlen(opnd) != 0;
case FILTT:
return isatty((int)getn(opnd));
default:
return filstat(opnd, n);
}
}
#ifndef SMALL
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) == NULL)
syntax(op->op_text, "argument expected");
return perform_binop(op->op_num, opnd1, opnd2);
}
#endif
static int
perform_binop(enum token op_num, const char *opnd1, const char *opnd2)
{
switch (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);
default:
abort();
/* NOTREACHED */
}
}
/*
* The manual, and IEEE POSIX 1003.2, suggests this should check the mode bits,
* not use access():
*
* True shall indicate only that the write flag is on. The file is not
* writable on a read-only file system even if this test indicates true.
*
* Unfortunately IEEE POSIX 1003.1-2001, as quoted in SuSv3, says only:
*
* True shall indicate that permission to read from file will be granted,
* as defined in "File Read, Write, and Creation".
*
* and that section says:
*
* When a file is to be read or written, the file shall be opened with an
* access mode corresponding to the operation to be performed. If file
* access permissions deny access, the requested operation shall fail.
*
* and of course access permissions are described as one might expect:
*
* * If a process has the appropriate privilege:
*
* * If read, write, or directory search permission is requested,
* access shall be granted.
*
* * If execute permission is requested, access shall be granted if
* execute permission is granted to at least one user by the file
* permission bits or by an alternate access control mechanism;
* otherwise, access shall be denied.
*
* * Otherwise:
*
* * The file permission bits of a file contain read, write, and
* execute/search permissions for the file owner class, file group
* class, and file other class.
*
* * Access shall be granted if an alternate access control mechanism
* is not enabled and the requested access permission bit is set for
* the class (file owner class, file group class, or file other class)
* to which the process belongs, or if an alternate access control
* mechanism is enabled and it allows the requested access; otherwise,
* access shall be denied.
*
* and when I first read this I thought: surely we can't go about using
* open(O_WRONLY) to try this test! However the POSIX 1003.1-2001 Rationale
* section for test does in fact say:
*
* On historical BSD systems, test -w directory always returned false
* because test tried to open the directory for writing, which always
* fails.
*
* and indeed this is in fact true for Seventh Edition UNIX, UNIX 32V, and UNIX
* System III, and thus presumably also for BSD up to and including 4.3.
*
* Secondly I remembered why using open() and/or access() are bogus. They
* don't work right for detecting read and write permissions bits when called
* by root.
*
* Interestingly the 'test' in 4.4BSD was closer to correct (as per
* 1003.2-1992) and it was implemented efficiently with stat() instead of
* open().
*
* This was apparently broken in NetBSD around about 1994/06/30 when the old
* 4.4BSD implementation was replaced with a (arguably much better coded)
* implementation derived from pdksh.
*
* Note that modern pdksh is yet different again, but still not correct, at
* least not w.r.t. 1003.2-1992.
*
* As I think more about it and read more of the related IEEE docs I don't like
* that wording about 'test -r' and 'test -w' in 1003.1-2001 at all. I very
* much prefer the original wording in 1003.2-1992. It is much more useful,
* and so that's what I've implemented.
*
* (Note that a strictly conforming implementation of 1003.1-2001 is in fact
* totally useless for the case in question since its 'test -w' and 'test -r'
* can never fail for root for any existing files, i.e. files for which 'test
* -e' succeeds.)
*
* The rationale for 1003.1-2001 suggests that the wording was "clarified" in
* 1003.1-2001 to align with the 1003.2b draft. 1003.2b Draft 12 (July 1999),
* which is the latest copy I have, does carry the same suggested wording as is
* in 1003.1-2001, with its rationale saying:
*
* This change is a clarification and is the result of interpretation
* request PASC 1003.2-92 #23 submitted for IEEE Std 1003.2-1992.
*
* That interpretation can be found here:
*
* http://www.pasc.org/interps/unofficial/db/p1003.2/pasc-1003.2-23.html
*
* Not terribly helpful, unfortunately. I wonder who that fence sitter was.
*
* Worse, IMVNSHO, I think the authors of 1003.2b-D12 have mis-interpreted the
* PASC interpretation and appear to be gone against at least one widely used
* implementation (namely 4.4BSD). The problem is that for file access by root
* this means that if test '-r' and '-w' are to behave as if open() were called
* then there's no way for a shell script running as root to check if a file
* has certain access bits set other than by the grotty means of interpreting
* the output of 'ls -l'. This was widely considered to be a bug in V7's
* "test" and is, I believe, one of the reasons why direct use of access() was
* avoided in some more recent implementations!
*
* I have always interpreted '-r' to match '-w' and '-x' as per the original
* wording in 1003.2-1992, not the other way around. I think 1003.2b goes much
* too far the wrong way without any valid rationale and that it's best if we
* stick with 1003.2-1992 and test the flags, and not mimic the behaviour of
* open() since we already know very well how it will work -- existance of the
* file is all that matters to open() for root.
*
* Unfortunately the SVID is no help at all (which is, I guess, partly why
* we're in this mess in the first place :-).
*
* The SysV implementation (at least in the 'test' builtin in /bin/sh) does use
* access(name, 2) even though it also goes to much greater lengths for '-x'
* matching the 1003.2-1992 definition (which is no doubt where that definition
* came from).
*
* The ksh93 implementation uses access() for '-r' and '-w' if
* (euid==uid&&egid==gid), but uses st_mode for '-x' iff running as root.
* i.e. it does strictly conform to 1003.1-2001 (and presumably 1003.2b).
*/
static int
test_access(struct stat *sp, mode_t stmode)
{
gid_t *groups;
register int n;
uid_t euid;
int maxgroups;
/*
* I suppose we could use access() if not running as root and if we are
* running with ((euid == uid) && (egid == gid)), but we've already
* done the stat() so we might as well just test the permissions
* directly instead of asking the kernel to do it....
*/
euid = geteuid();
if (euid == 0) /* any bit is good enough */
stmode = (stmode << 6) | (stmode << 3) | stmode;
else if (sp->st_uid == euid)
stmode <<= 6;
else if (sp->st_gid == getegid())
stmode <<= 3;
else {
/* XXX stolen almost verbatim from ksh93.... */
/* on some systems you can be in several groups */
if ((maxgroups = getgroups(0, NULL)) <= 0)
maxgroups = NGROUPS_MAX; /* pre-POSIX system? */
groups = ckmalloc((maxgroups + 1) * sizeof(gid_t));
n = getgroups(maxgroups, groups);
while (--n >= 0) {
if (groups[n] == sp->st_gid) {
stmode <<= 3;
break;
}
}
free(groups);
}
return sp->st_mode & stmode;
}
static int
filstat(const char *nm, enum token mode)
{
struct stat s;
if (mode == FILSYM ? lstat(nm, &s) : stat(nm, &s))
return 0;
switch (mode) {
case FILRD:
return test_access(&s, S_IROTH);
case FILWR:
return test_access(&s, S_IWOTH);
case FILEX:
return test_access(&s, S_IXOTH);
case FILEXIST:
return 1; /* the successful lstat()/stat() is good enough */
case FILREG:
return S_ISREG(s.st_mode);
case FILDIR:
return S_ISDIR(s.st_mode);
case FILCDEV:
return S_ISCHR(s.st_mode);
case FILBDEV:
return S_ISBLK(s.st_mode);
case FILFIFO:
return S_ISFIFO(s.st_mode);
case FILSOCK:
return S_ISSOCK(s.st_mode);
case FILSYM:
return S_ISLNK(s.st_mode);
case FILSUID:
return (s.st_mode & S_ISUID) != 0;
case FILSGID:
return (s.st_mode & S_ISGID) != 0;
case FILSTCK:
return (s.st_mode & S_ISVTX) != 0;
case FILGZ:
return s.st_size > (off_t)0;
case FILUID:
return s.st_uid == geteuid();
case FILGID:
return s.st_gid == getegid();
default:
return 1;
}
}
#define VTOC(x) (const unsigned char *)((const struct t_op *)x)->op_text
static int
compare1(const void *va, const void *vb)
{
const unsigned char *a = va;
const unsigned char *b = VTOC(vb);
return a[0] - b[0];
}
static int
compare2(const void *va, const void *vb)
{
const unsigned char *a = va;
const unsigned char *b = VTOC(vb);
int z = a[0] - b[0];
return z ? z : (a[1] - b[1]);
}
static struct t_op const *
findop(const char *s)
{
if (s[0] == '-') {
if (s[1] == '\0')
return NULL;
if (s[2] == '\0')
return bsearch(s + 1, mop2, __arraycount(mop2),
sizeof(*mop2), compare1);
else if (s[3] != '\0')
return NULL;
else
return bsearch(s + 1, mop3, __arraycount(mop3),
sizeof(*mop3), compare2);
} else {
if (s[1] == '\0')
return bsearch(s, cop, __arraycount(cop), sizeof(*cop),
compare1);
else if (strcmp(s, cop2[0].op_text) == 0)
return cop2;
else
return NULL;
}
}
#ifndef SMALL
static enum token
t_lex(char *s)
{
struct t_op const *op;
if (s == NULL) {
t_wp_op = NULL;
return EOI;
}
if ((op = findop(s)) != NULL) {
if (!((op->op_type == UNOP && isoperand()) ||
(op->op_num == LPAREN && *(t_wp+1) == 0))) {
t_wp_op = op;
return op->op_num;
}
}
t_wp_op = NULL;
return OPERAND;
}
static int
isoperand(void)
{
struct t_op const *op;
char *s, *t;
if ((s = *(t_wp+1)) == 0)
return 1;
if ((t = *(t_wp+2)) == 0)
return 0;
if ((op = findop(s)) != NULL)
return op->op_type == BINOP && (t[0] != ')' || t[1] != '\0');
return 0;
}
#endif
/* atoi with error detection */
static long long
getn(const char *s)
{
char *p;
long long r;
errno = 0;
r = strtoll(s, &p, 10);
if (errno != 0)
if (errno == ERANGE && (r == LLONG_MAX || r == LLONG_MIN))
error("%s: out of range", s);
if (p != s)
while (isspace((unsigned char)*p))
p++;
if (*p || p == s)
error("'%s': bad number", s);
return r;
}
static int
newerf(const char *f1, const char *f2)
{
struct stat b1, b2;
return (stat(f1, &b1) == 0 &&
stat(f2, &b2) == 0 &&
timespeccmp(&b1.st_mtim, &b2.st_mtim, >));
}
static int
olderf(const char *f1, const char *f2)
{
struct stat b1, b2;
return (stat(f1, &b1) == 0 &&
stat(f2, &b2) == 0 &&
timespeccmp(&b1.st_mtim, &b2.st_mtim, <));
}
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);
}