freebsd-dev/bin/rm/rm.c
Baptiste Daroussin 8e5c71e2d6 Protecting against rm -rf / is now POSIXLY_CORRECT per posix 1003.1
edition 2013. No need anymore to disable the protection if one set
the POXILY_CORRECT environment variable.

Reviewed by:	imp
MFC after:	3 days
Differential Revision:	https://reviews.freebsd.org/D4092
2015-11-07 02:18:19 +00:00

645 lines
14 KiB
C

/*-
* Copyright (c) 1990, 1993, 1994
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#if 0
#ifndef lint
static const char copyright[] =
"@(#) Copyright (c) 1990, 1993, 1994\n\
The Regents of the University of California. All rights reserved.\n";
#endif /* not lint */
#ifndef lint
static char sccsid[] = "@(#)rm.c 8.5 (Berkeley) 4/18/94";
#endif /* not lint */
#endif
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/stat.h>
#include <sys/param.h>
#include <sys/mount.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <fts.h>
#include <grp.h>
#include <locale.h>
#include <pwd.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sysexits.h>
#include <unistd.h>
static int dflag, eval, fflag, iflag, Pflag, vflag, Wflag, stdin_ok;
static int rflag, Iflag, xflag;
static uid_t uid;
static volatile sig_atomic_t info;
static int check(const char *, const char *, struct stat *);
static int check2(char **);
static void checkdot(char **);
static void checkslash(char **);
static void rm_file(char **);
static int rm_overwrite(const char *, struct stat *);
static void rm_tree(char **);
static void siginfo(int __unused);
static void usage(void);
/*
* rm --
* This rm is different from historic rm's, but is expected to match
* POSIX 1003.2 behavior. The most visible difference is that -f
* has two specific effects now, ignore non-existent files and force
* file removal.
*/
int
main(int argc, char *argv[])
{
int ch;
char *p;
(void)setlocale(LC_ALL, "");
/*
* Test for the special case where the utility is called as
* "unlink", for which the functionality provided is greatly
* simplified.
*/
if ((p = strrchr(argv[0], '/')) == NULL)
p = argv[0];
else
++p;
if (strcmp(p, "unlink") == 0) {
while (getopt(argc, argv, "") != -1)
usage();
argc -= optind;
argv += optind;
if (argc != 1)
usage();
rm_file(&argv[0]);
exit(eval);
}
Pflag = rflag = xflag = 0;
while ((ch = getopt(argc, argv, "dfiIPRrvWx")) != -1)
switch(ch) {
case 'd':
dflag = 1;
break;
case 'f':
fflag = 1;
iflag = 0;
break;
case 'i':
fflag = 0;
iflag = 1;
break;
case 'I':
Iflag = 1;
break;
case 'P':
Pflag = 1;
break;
case 'R':
case 'r': /* Compatibility. */
rflag = 1;
break;
case 'v':
vflag = 1;
break;
case 'W':
Wflag = 1;
break;
case 'x':
xflag = 1;
break;
default:
usage();
}
argc -= optind;
argv += optind;
if (argc < 1) {
if (fflag)
return (0);
usage();
}
checkdot(argv);
checkslash(argv);
uid = geteuid();
(void)signal(SIGINFO, siginfo);
if (*argv) {
stdin_ok = isatty(STDIN_FILENO);
if (Iflag) {
if (check2(argv) == 0)
exit (1);
}
if (rflag)
rm_tree(argv);
else
rm_file(argv);
}
exit (eval);
}
static void
rm_tree(char **argv)
{
FTS *fts;
FTSENT *p;
int needstat;
int flags;
int rval;
/*
* Remove a file hierarchy. If forcing removal (-f), or interactive
* (-i) or can't ask anyway (stdin_ok), don't stat the file.
*/
needstat = !uid || (!fflag && !iflag && stdin_ok);
/*
* If the -i option is specified, the user can skip on the pre-order
* visit. The fts_number field flags skipped directories.
*/
#define SKIPPED 1
flags = FTS_PHYSICAL;
if (!needstat)
flags |= FTS_NOSTAT;
if (Wflag)
flags |= FTS_WHITEOUT;
if (xflag)
flags |= FTS_XDEV;
if (!(fts = fts_open(argv, flags, NULL))) {
if (fflag && errno == ENOENT)
return;
err(1, "fts_open");
}
while ((p = fts_read(fts)) != NULL) {
switch (p->fts_info) {
case FTS_DNR:
if (!fflag || p->fts_errno != ENOENT) {
warnx("%s: %s",
p->fts_path, strerror(p->fts_errno));
eval = 1;
}
continue;
case FTS_ERR:
errx(1, "%s: %s", p->fts_path, strerror(p->fts_errno));
case FTS_NS:
/*
* Assume that since fts_read() couldn't stat the
* file, it can't be unlinked.
*/
if (!needstat)
break;
if (!fflag || p->fts_errno != ENOENT) {
warnx("%s: %s",
p->fts_path, strerror(p->fts_errno));
eval = 1;
}
continue;
case FTS_D:
/* Pre-order: give user chance to skip. */
if (!fflag && !check(p->fts_path, p->fts_accpath,
p->fts_statp)) {
(void)fts_set(fts, p, FTS_SKIP);
p->fts_number = SKIPPED;
}
else if (!uid &&
(p->fts_statp->st_flags & (UF_APPEND|UF_IMMUTABLE)) &&
!(p->fts_statp->st_flags & (SF_APPEND|SF_IMMUTABLE)) &&
lchflags(p->fts_accpath,
p->fts_statp->st_flags &= ~(UF_APPEND|UF_IMMUTABLE)) < 0)
goto err;
continue;
case FTS_DP:
/* Post-order: see if user skipped. */
if (p->fts_number == SKIPPED)
continue;
break;
default:
if (!fflag &&
!check(p->fts_path, p->fts_accpath, p->fts_statp))
continue;
}
rval = 0;
if (!uid &&
(p->fts_statp->st_flags & (UF_APPEND|UF_IMMUTABLE)) &&
!(p->fts_statp->st_flags & (SF_APPEND|SF_IMMUTABLE)))
rval = lchflags(p->fts_accpath,
p->fts_statp->st_flags &= ~(UF_APPEND|UF_IMMUTABLE));
if (rval == 0) {
/*
* If we can't read or search the directory, may still be
* able to remove it. Don't print out the un{read,search}able
* message unless the remove fails.
*/
switch (p->fts_info) {
case FTS_DP:
case FTS_DNR:
rval = rmdir(p->fts_accpath);
if (rval == 0 || (fflag && errno == ENOENT)) {
if (rval == 0 && vflag)
(void)printf("%s\n",
p->fts_path);
if (rval == 0 && info) {
info = 0;
(void)printf("%s\n",
p->fts_path);
}
continue;
}
break;
case FTS_W:
rval = undelete(p->fts_accpath);
if (rval == 0 && (fflag && errno == ENOENT)) {
if (vflag)
(void)printf("%s\n",
p->fts_path);
if (info) {
info = 0;
(void)printf("%s\n",
p->fts_path);
}
continue;
}
break;
case FTS_NS:
/*
* Assume that since fts_read() couldn't stat
* the file, it can't be unlinked.
*/
if (fflag)
continue;
/* FALLTHROUGH */
case FTS_F:
case FTS_NSOK:
if (Pflag)
if (!rm_overwrite(p->fts_accpath, p->fts_info ==
FTS_NSOK ? NULL : p->fts_statp))
continue;
/* FALLTHROUGH */
default:
rval = unlink(p->fts_accpath);
if (rval == 0 || (fflag && errno == ENOENT)) {
if (rval == 0 && vflag)
(void)printf("%s\n",
p->fts_path);
if (rval == 0 && info) {
info = 0;
(void)printf("%s\n",
p->fts_path);
}
continue;
}
}
}
err:
warn("%s", p->fts_path);
eval = 1;
}
if (!fflag && errno)
err(1, "fts_read");
fts_close(fts);
}
static void
rm_file(char **argv)
{
struct stat sb;
int rval;
char *f;
/*
* Remove a file. POSIX 1003.2 states that, by default, attempting
* to remove a directory is an error, so must always stat the file.
*/
while ((f = *argv++) != NULL) {
/* Assume if can't stat the file, can't unlink it. */
if (lstat(f, &sb)) {
if (Wflag) {
sb.st_mode = S_IFWHT|S_IWUSR|S_IRUSR;
} else {
if (!fflag || errno != ENOENT) {
warn("%s", f);
eval = 1;
}
continue;
}
} else if (Wflag) {
warnx("%s: %s", f, strerror(EEXIST));
eval = 1;
continue;
}
if (S_ISDIR(sb.st_mode) && !dflag) {
warnx("%s: is a directory", f);
eval = 1;
continue;
}
if (!fflag && !S_ISWHT(sb.st_mode) && !check(f, f, &sb))
continue;
rval = 0;
if (!uid && !S_ISWHT(sb.st_mode) &&
(sb.st_flags & (UF_APPEND|UF_IMMUTABLE)) &&
!(sb.st_flags & (SF_APPEND|SF_IMMUTABLE)))
rval = lchflags(f, sb.st_flags & ~(UF_APPEND|UF_IMMUTABLE));
if (rval == 0) {
if (S_ISWHT(sb.st_mode))
rval = undelete(f);
else if (S_ISDIR(sb.st_mode))
rval = rmdir(f);
else {
if (Pflag)
if (!rm_overwrite(f, &sb))
continue;
rval = unlink(f);
}
}
if (rval && (!fflag || errno != ENOENT)) {
warn("%s", f);
eval = 1;
}
if (vflag && rval == 0)
(void)printf("%s\n", f);
if (info && rval == 0) {
info = 0;
(void)printf("%s\n", f);
}
}
}
/*
* rm_overwrite --
* Overwrite the file 3 times with varying bit patterns.
*
* XXX
* This is a cheap way to *really* delete files. Note that only regular
* files are deleted, directories (and therefore names) will remain.
* Also, this assumes a fixed-block file system (like FFS, or a V7 or a
* System V file system). In a logging or COW file system, you'll have to
* have kernel support.
*/
static int
rm_overwrite(const char *file, struct stat *sbp)
{
struct stat sb, sb2;
struct statfs fsb;
off_t len;
int bsize, fd, wlen;
char *buf = NULL;
fd = -1;
if (sbp == NULL) {
if (lstat(file, &sb))
goto err;
sbp = &sb;
}
if (!S_ISREG(sbp->st_mode))
return (1);
if (sbp->st_nlink > 1 && !fflag) {
warnx("%s (inode %ju): not overwritten due to multiple links",
file, (uintmax_t)sbp->st_ino);
return (0);
}
if ((fd = open(file, O_WRONLY|O_NONBLOCK|O_NOFOLLOW, 0)) == -1)
goto err;
if (fstat(fd, &sb2))
goto err;
if (sb2.st_dev != sbp->st_dev || sb2.st_ino != sbp->st_ino ||
!S_ISREG(sb2.st_mode)) {
errno = EPERM;
goto err;
}
if (fstatfs(fd, &fsb) == -1)
goto err;
bsize = MAX(fsb.f_iosize, 1024);
if ((buf = malloc(bsize)) == NULL)
err(1, "%s: malloc", file);
#define PASS(byte) { \
memset(buf, byte, bsize); \
for (len = sbp->st_size; len > 0; len -= wlen) { \
wlen = len < bsize ? len : bsize; \
if (write(fd, buf, wlen) != wlen) \
goto err; \
} \
}
PASS(0xff);
if (fsync(fd) || lseek(fd, (off_t)0, SEEK_SET))
goto err;
PASS(0x00);
if (fsync(fd) || lseek(fd, (off_t)0, SEEK_SET))
goto err;
PASS(0xff);
if (!fsync(fd) && !close(fd)) {
free(buf);
return (1);
}
err: eval = 1;
if (buf)
free(buf);
if (fd != -1)
close(fd);
warn("%s", file);
return (0);
}
static int
check(const char *path, const char *name, struct stat *sp)
{
int ch, first;
char modep[15], *flagsp;
/* Check -i first. */
if (iflag)
(void)fprintf(stderr, "remove %s? ", path);
else {
/*
* If it's not a symbolic link and it's unwritable and we're
* talking to a terminal, ask. Symbolic links are excluded
* because their permissions are meaningless. Check stdin_ok
* first because we may not have stat'ed the file.
*/
if (!stdin_ok || S_ISLNK(sp->st_mode) ||
(!access(name, W_OK) &&
!(sp->st_flags & (SF_APPEND|SF_IMMUTABLE)) &&
(!(sp->st_flags & (UF_APPEND|UF_IMMUTABLE)) || !uid)))
return (1);
strmode(sp->st_mode, modep);
if ((flagsp = fflagstostr(sp->st_flags)) == NULL)
err(1, "fflagstostr");
if (Pflag)
errx(1,
"%s: -P was specified, but file is not writable",
path);
(void)fprintf(stderr, "override %s%s%s/%s %s%sfor %s? ",
modep + 1, modep[9] == ' ' ? "" : " ",
user_from_uid(sp->st_uid, 0),
group_from_gid(sp->st_gid, 0),
*flagsp ? flagsp : "", *flagsp ? " " : "",
path);
free(flagsp);
}
(void)fflush(stderr);
first = ch = getchar();
while (ch != '\n' && ch != EOF)
ch = getchar();
return (first == 'y' || first == 'Y');
}
#define ISSLASH(a) ((a)[0] == '/' && (a)[1] == '\0')
static void
checkslash(char **argv)
{
char **t, **u;
int complained;
complained = 0;
for (t = argv; *t;) {
if (ISSLASH(*t)) {
if (!complained++)
warnx("\"/\" may not be removed");
eval = 1;
for (u = t; u[0] != NULL; ++u)
u[0] = u[1];
} else {
++t;
}
}
}
static int
check2(char **argv)
{
struct stat st;
int first;
int ch;
int fcount = 0;
int dcount = 0;
int i;
const char *dname = NULL;
for (i = 0; argv[i]; ++i) {
if (lstat(argv[i], &st) == 0) {
if (S_ISDIR(st.st_mode)) {
++dcount;
dname = argv[i]; /* only used if 1 dir */
} else {
++fcount;
}
}
}
first = 0;
while (first != 'n' && first != 'N' && first != 'y' && first != 'Y') {
if (dcount && rflag) {
fprintf(stderr, "recursively remove");
if (dcount == 1)
fprintf(stderr, " %s", dname);
else
fprintf(stderr, " %d dirs", dcount);
if (fcount == 1)
fprintf(stderr, " and 1 file");
else if (fcount > 1)
fprintf(stderr, " and %d files", fcount);
} else if (dcount + fcount > 3) {
fprintf(stderr, "remove %d files", dcount + fcount);
} else {
return(1);
}
fprintf(stderr, "? ");
fflush(stderr);
first = ch = getchar();
while (ch != '\n' && ch != EOF)
ch = getchar();
if (ch == EOF)
break;
}
return (first == 'y' || first == 'Y');
}
#define ISDOT(a) ((a)[0] == '.' && (!(a)[1] || ((a)[1] == '.' && !(a)[2])))
static void
checkdot(char **argv)
{
char *p, **save, **t;
int complained;
complained = 0;
for (t = argv; *t;) {
if ((p = strrchr(*t, '/')) != NULL)
++p;
else
p = *t;
if (ISDOT(p)) {
if (!complained++)
warnx("\".\" and \"..\" may not be removed");
eval = 1;
for (save = t; (t[0] = t[1]) != NULL; ++t)
continue;
t = save;
} else
++t;
}
}
static void
usage(void)
{
(void)fprintf(stderr, "%s\n%s\n",
"usage: rm [-f | -i] [-dIPRrvWx] file ...",
" unlink file");
exit(EX_USAGE);
}
static void
siginfo(int sig __unused)
{
info = 1;
}