sanchayanmaity
/
minix
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity
minix/bin/test/test.c

720 lines
17 KiB
C
Raw Blame History

/* $NetBSD: test.c,v 1.40 2013/05/04 06:26:44 uebayasi 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 1.40 2013/05/04 06:26:44 uebayasi 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,
BUNOP,
BBINOP,
PAREN
};
struct t_op {
const char *op_text;
short op_num, op_type;
};
static const struct t_op cop[] = {
{"!", UNOT, BUNOP},
{"(", LPAREN, PAREN},
{")", RPAREN, PAREN},
{"<", 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},
{"a", BAND, BBINOP},
{"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},
{"o", BOR, BBINOP},
{"p", FILFIFO,UNOP},
{"r", FILRD, UNOP},
{"s", FILGZ, UNOP},
{"t", FILTT, UNOP},
{"u", FILSUID,UNOP},
{"w", FILWR, UNOP},
{"x", FILEX, UNOP},
{"z", STREZ, UNOP},
};
static char **t_wp;
static struct t_op const *t_wp_op;
__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 int test_access(struct stat *, mode_t);
static int filstat(char *, enum token);
static enum token t_lex(char *);
static int isoperand(void);
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 *);
#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, char *[]);
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;
}
if (argc < 2)
return 1;
t_wp = &argv[1];
res = !oexpr(t_lex(*t_wp));
if (*t_wp != NULL && *++t_wp != NULL)
syntax(*t_wp, "unexpected operator");
return res;
}
static void
syntax(const char *op, const char *msg)
{
if (op && *op)
error("%s: %s", op, msg);
else
error("%s", msg);
}
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");
switch (n) {
case STREZ:
return strlen(*t_wp) == 0;
case STRNZ:
return strlen(*t_wp) != 0;
case FILTT:
return isatty((int)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) == NULL)
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);
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(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;
}
}
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;
}
/* 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);
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);
}
Reference in New Issue View Git Blame Copy Permalink