busybox/libbb/copy_file.c

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/* vi: set sw=4 ts=4: */
/*
* Mini copy_file implementation for busybox
*
* Copyright (C) 2001 by Matt Kraai <kraai@alumni.carnegiemellon.edu>
* SELinux support by Yuichi Nakamura <ynakam@hitachisoft.jp>
*
* Licensed under GPLv2 or later, see file LICENSE in this source tree.
*/
#include "libbb.h"
// FEATURE_NON_POSIX_CP:
//
// POSIX: if exists and -i, ask (w/o -i assume yes).
// Then open w/o EXCL (yes, not unlink!).
// If open still fails and -f, try unlink, then try open again.
// Result: a mess:
// If dest is a (sym)link, we overwrite link destination!
// (or fail, if it points to dir/nonexistent location/etc).
// This is strange, but POSIX-correct.
// coreutils cp has --remove-destination to override this...
/* Called if open of destination, link creation etc fails.
* errno must be set to relevant value ("why we cannot create dest?")
* to give reasonable error message */
static int ask_and_unlink(const char *dest, int flags)
{
int e = errno;
#if !ENABLE_FEATURE_NON_POSIX_CP
if (!(flags & (FILEUTILS_FORCE|FILEUTILS_INTERACTIVE))) {
/* Either it exists, or the *path* doesnt exist */
bb_perror_msg("can't create '%s'", dest);
return -1;
}
#endif
// else: act as if -f is always in effect.
// We don't want "can't create" msg, we want unlink to be done
// (silently unless -i). Why? POSIX cp usually succeeds with
// O_TRUNC open of existing file, and user is left ignorantly happy.
// With above block unconditionally enabled, non-POSIX cp
// will complain a lot more than POSIX one.
/* TODO: maybe we should do it only if ctty is present? */
if (flags & FILEUTILS_INTERACTIVE) {
// We would not do POSIX insanity. -i asks,
// then _unlinks_ the offender. Presto.
// (No "opening without O_EXCL", no "unlink only if -f")
// Or else we will end up having 3 open()s!
fprintf(stderr, "%s: overwrite '%s'? ", applet_name, dest);
if (!bb_ask_y_confirmation())
return 0; /* not allowed to overwrite */
}
if (unlink(dest) < 0) {
#if ENABLE_FEATURE_VERBOSE_CP_MESSAGE
if (e == errno && e == ENOENT) {
/* e == ENOTDIR is similar: path has non-dir component,
* but in this case we don't even reach copy_file() */
bb_error_msg("can't create '%s': Path does not exist", dest);
return -1; /* error */
}
#endif
errno = e; /* do not use errno from unlink */
bb_perror_msg("can't create '%s'", dest);
return -1; /* error */
}
#if ENABLE_FEATURE_CP_LONG_OPTIONS
if (flags & FILEUTILS_RMDEST)
if (flags & FILEUTILS_VERBOSE)
printf("removed '%s'\n", dest);
#endif
return 1; /* ok (to try again) */
}
/* Return:
* -1 error, copy not made
* 0 copy is made or user answered "no" in interactive mode
* (failures to preserve mode/owner/times are not reported in exit code)
*/
int FAST_FUNC copy_file(const char *source, const char *dest, int flags)
{
/* This is a recursive function, try to minimize stack usage */
/* NB: each struct stat is ~100 bytes */
struct stat source_stat;
struct stat dest_stat;
smallint retval = 0;
smallint dest_exists = 0;
smallint ovr;
/* Inverse of cp -d ("cp without -d") */
#define FLAGS_DEREF (flags & (FILEUTILS_DEREFERENCE + FILEUTILS_DEREFERENCE_L0))
if ((FLAGS_DEREF ? stat : lstat)(source, &source_stat) < 0) {
/* This may be a dangling symlink.
* Making [sym]links to dangling symlinks works, so... */
if (flags & (FILEUTILS_MAKE_SOFTLINK|FILEUTILS_MAKE_HARDLINK))
goto make_links;
bb_perror_msg("can't stat '%s'", source);
return -1;
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}
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if (lstat(dest, &dest_stat) < 0) {
if (errno != ENOENT) {
bb_perror_msg("can't stat '%s'", dest);
return -1;
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}
} else {
if (source_stat.st_dev == dest_stat.st_dev
&& source_stat.st_ino == dest_stat.st_ino
) {
bb_error_msg("'%s' and '%s' are the same file", source, dest);
return -1;
}
if (flags & FILEUTILS_NO_OVERWRITE) /* cp -n */
return 0;
dest_exists = 1;
}
#if ENABLE_SELINUX
if ((flags & FILEUTILS_PRESERVE_SECURITY_CONTEXT) && is_selinux_enabled() > 0) {
security_context_t con;
if (lgetfilecon(source, &con) >= 0) {
if (setfscreatecon(con) < 0) {
bb_perror_msg("can't set setfscreatecon %s", con);
freecon(con);
return -1;
}
} else if (errno == ENOTSUP || errno == ENODATA) {
setfscreatecon_or_die(NULL);
} else {
bb_perror_msg("can't lgetfilecon %s", source);
return -1;
}
}
#endif
if (S_ISDIR(source_stat.st_mode)) {
DIR *dp;
const char *tp;
struct dirent *d;
mode_t saved_umask = 0;
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if (!(flags & FILEUTILS_RECUR)) {
bb_error_msg("omitting directory '%s'", source);
return -1;
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}
/* Did we ever create source ourself before? */
tp = is_in_ino_dev_hashtable(&source_stat);
if (tp) {
/* We did! it's a recursion! man the lifeboats... */
bb_error_msg("recursion detected, omitting directory '%s'",
source);
return -1;
}
if (dest_exists) {
if (!S_ISDIR(dest_stat.st_mode)) {
bb_error_msg("target '%s' is not a directory", dest);
return -1;
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}
/* race here: user can substitute a symlink between
* this check and actual creation of files inside dest */
} else {
/* Create DEST */
mode_t mode;
saved_umask = umask(0);
mode = source_stat.st_mode;
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if (!(flags & FILEUTILS_PRESERVE_STATUS))
mode = source_stat.st_mode & ~saved_umask;
/* Allow owner to access new dir (at least for now) */
mode |= S_IRWXU;
if (mkdir(dest, mode) < 0) {
umask(saved_umask);
bb_perror_msg("can't create directory '%s'", dest);
return -1;
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}
umask(saved_umask);
/* need stat info for add_to_ino_dev_hashtable */
if (lstat(dest, &dest_stat) < 0) {
bb_perror_msg("can't stat '%s'", dest);
return -1;
}
}
/* remember (dev,inode) of each created dir.
* NULL: name is not remembered */
add_to_ino_dev_hashtable(&dest_stat, NULL);
/* Recursively copy files in SOURCE */
dp = opendir(source);
if (dp == NULL) {
retval = -1;
goto preserve_mode_ugid_time;
}
while ((d = readdir(dp)) != NULL) {
char *new_source, *new_dest;
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new_source = concat_subpath_file(source, d->d_name);
if (new_source == NULL)
continue;
new_dest = concat_path_file(dest, d->d_name);
if (copy_file(new_source, new_dest, flags & ~FILEUTILS_DEREFERENCE_L0) < 0)
retval = -1;
free(new_source);
free(new_dest);
}
closedir(dp);
if (!dest_exists
&& chmod(dest, source_stat.st_mode & ~saved_umask) < 0
) {
bb_perror_msg("can't preserve %s of '%s'", "permissions", dest);
/* retval = -1; - WRONG! copy *WAS* made */
}
goto preserve_mode_ugid_time;
}
if (dest_exists) {
if (flags & FILEUTILS_UPDATE) {
if (source_stat.st_mtime <= dest_stat.st_mtime) {
return 0; /* source file must be newer */
}
}
#if ENABLE_FEATURE_CP_LONG_OPTIONS
if (flags & FILEUTILS_RMDEST) {
ovr = ask_and_unlink(dest, flags);
if (ovr <= 0)
return ovr;
dest_exists = 0;
}
#endif
}
if (flags & (FILEUTILS_MAKE_SOFTLINK|FILEUTILS_MAKE_HARDLINK)) {
int (*lf)(const char *oldpath, const char *newpath);
make_links:
/* Hmm... maybe
* if (DEREF && MAKE_SOFTLINK) source = realpath(source) ?
* (but realpath returns NULL on dangling symlinks...) */
lf = (flags & FILEUTILS_MAKE_SOFTLINK) ? symlink : link;
if (lf(source, dest) < 0) {
ovr = ask_and_unlink(dest, flags);
if (ovr <= 0)
return ovr;
if (lf(source, dest) < 0) {
bb_perror_msg("can't create link '%s'", dest);
return -1;
}
}
/* _Not_ jumping to preserve_mode_ugid_time:
* (sym)links don't have those */
return 0;
}
if (/* "cp thing1 thing2" without -R: just open and read() from thing1 */
!(flags & FILEUTILS_RECUR)
/* "cp [-opts] regular_file thing2" */
|| S_ISREG(source_stat.st_mode)
/* DEREF uses stat, which never returns S_ISLNK() == true.
* So the below is never true: */
/* || (FLAGS_DEREF && S_ISLNK(source_stat.st_mode)) */
) {
int src_fd;
int dst_fd;
mode_t new_mode;
if (!FLAGS_DEREF && S_ISLNK(source_stat.st_mode)) {
/* "cp -d symlink dst": create a link */
goto dont_cat;
}
if (ENABLE_FEATURE_PRESERVE_HARDLINKS && !FLAGS_DEREF) {
const char *link_target;
link_target = is_in_ino_dev_hashtable(&source_stat);
if (link_target) {
if (link(link_target, dest) < 0) {
ovr = ask_and_unlink(dest, flags);
if (ovr <= 0)
return ovr;
if (link(link_target, dest) < 0) {
bb_perror_msg("can't create link '%s'", dest);
return -1;
}
}
return 0;
}
add_to_ino_dev_hashtable(&source_stat, dest);
}
src_fd = open_or_warn(source, O_RDONLY);
if (src_fd < 0)
return -1;
/* Do not try to open with weird mode fields */
new_mode = source_stat.st_mode;
if (!S_ISREG(source_stat.st_mode))
new_mode = 0666;
if (ENABLE_FEATURE_NON_POSIX_CP || (flags & FILEUTILS_INTERACTIVE)) {
/*
* O_CREAT|O_EXCL: require that file did not exist before creation
*/
dst_fd = open(dest, O_WRONLY|O_CREAT|O_EXCL, new_mode);
} else { /* POSIX, and not "cp -i" */
/*
* O_CREAT|O_TRUNC: create, or truncate (security problem versus (sym)link attacks)
*/
dst_fd = open(dest, O_WRONLY|O_CREAT|O_TRUNC, new_mode);
}
if (dst_fd == -1) {
ovr = ask_and_unlink(dest, flags);
if (ovr <= 0) {
close(src_fd);
return ovr;
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}
/* It shouldn't exist. If it exists, do not open (symlink attack?) */
dst_fd = open3_or_warn(dest, O_WRONLY|O_CREAT|O_EXCL, new_mode);
if (dst_fd < 0) {
close(src_fd);
return -1;
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}
}
#if ENABLE_SELINUX
if ((flags & (FILEUTILS_PRESERVE_SECURITY_CONTEXT|FILEUTILS_SET_SECURITY_CONTEXT))
&& is_selinux_enabled() > 0
) {
security_context_t con;
if (getfscreatecon(&con) == -1) {
libbb: reduce the overhead of single parameter bb_error_msg() calls Back in 2007, commit 0c97c9d43707 ("'simple' error message functions by Loic Grenie") introduced bb_simple_perror_msg() to allow for a lower overhead call to bb_perror_msg() when only a string was being printed with no parameters. This saves space for some CPU architectures because it avoids the overhead of a call to a variadic function. However there has never been a simple version of bb_error_msg(), and since 2007 many new calls to bb_perror_msg() have been added that only take a single parameter and so could have been using bb_simple_perror_message(). This changeset introduces 'simple' versions of bb_info_msg(), bb_error_msg(), bb_error_msg_and_die(), bb_herror_msg() and bb_herror_msg_and_die(), and replaces all calls that only take a single parameter, or use something like ("%s", arg), with calls to the corresponding 'simple' version. Since it is likely that single parameter calls to the variadic functions may be accidentally reintroduced in the future a new debugging config option WARN_SIMPLE_MSG has been introduced. This uses some macro magic which will cause any such calls to generate a warning, but this is turned off by default to avoid use of the unpleasant macros in normal circumstances. This is a large changeset due to the number of calls that have been replaced. The only files that contain changes other than simple substitution of function calls are libbb.h, libbb/herror_msg.c, libbb/verror_msg.c and libbb/xfuncs_printf.c. In miscutils/devfsd.c, networking/udhcp/common.h and util-linux/mdev.c additonal macros have been added for logging so that single parameter and multiple parameter logging variants exist. The amount of space saved varies considerably by architecture, and was found to be as follows (for 'defconfig' using GCC 7.4): Arm: -92 bytes MIPS: -52 bytes PPC: -1836 bytes x86_64: -938 bytes Note that for the MIPS architecture only an exception had to be made disabling the 'simple' calls for 'udhcp' (in networking/udhcp/common.h) because it made these files larger on MIPS. Signed-off-by: James Byrne <james.byrne@origamienergy.com> Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
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bb_simple_perror_msg("getfscreatecon");
return -1;
}
if (con) {
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if (setfilecon(dest, con) == -1) {
bb_perror_msg("setfilecon:%s,%s", dest, con);
freecon(con);
return -1;
}
freecon(con);
}
}
#endif
#if ENABLE_FEATURE_CP_REFLINK
# undef BTRFS_IOCTL_MAGIC
# define BTRFS_IOCTL_MAGIC 0x94
# undef BTRFS_IOC_CLONE
# define BTRFS_IOC_CLONE _IOW (BTRFS_IOCTL_MAGIC, 9, int)
if (flags & FILEUTILS_REFLINK) {
retval = ioctl(dst_fd, BTRFS_IOC_CLONE, src_fd);
if (retval == 0)
goto do_close;
/* reflink did not work */
if (flags & FILEUTILS_REFLINK_ALWAYS) {
bb_perror_msg("failed to clone '%s' from '%s'", dest, source);
goto do_close;
}
/* fall through to standard copy */
retval = 0;
}
#endif
if (bb_copyfd_eof(src_fd, dst_fd) == -1)
retval = -1;
IF_FEATURE_CP_REFLINK(do_close:)
/* Careful with writing... */
if (close(dst_fd) < 0) {
bb_perror_msg("error writing to '%s'", dest);
retval = -1;
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}
/* ...but read size is already checked by bb_copyfd_eof */
close(src_fd);
/* "cp /dev/something new_file" should not
* copy mode of /dev/something */
if (!S_ISREG(source_stat.st_mode))
return retval;
goto preserve_mode_ugid_time;
}
dont_cat:
/* Source is a symlink or a special file */
/* We are lazy here, a bit lax with races... */
if (dest_exists) {
errno = EEXIST;
ovr = ask_and_unlink(dest, flags);
if (ovr <= 0)
return ovr;
}
if (S_ISLNK(source_stat.st_mode)) {
char *lpath = xmalloc_readlink_or_warn(source);
if (lpath) {
int r = symlink(lpath, dest);
if (r < 0) {
/* shared message */
bb_perror_msg("can't create %slink '%s' to '%s'",
"sym", dest, lpath
);
free(lpath);
return -1;
}
free(lpath);
if (flags & FILEUTILS_PRESERVE_STATUS)
if (lchown(dest, source_stat.st_uid, source_stat.st_gid) < 0)
bb_perror_msg("can't preserve %s of '%s'", "ownership", dest);
}
/* _Not_ jumping to preserve_mode_ugid_time:
* symlinks don't have those */
goto verb_and_exit;
}
if (S_ISBLK(source_stat.st_mode) || S_ISCHR(source_stat.st_mode)
|| S_ISSOCK(source_stat.st_mode) || S_ISFIFO(source_stat.st_mode)
) {
if (mknod(dest, source_stat.st_mode, source_stat.st_rdev) < 0) {
bb_perror_msg("can't create '%s'", dest);
return -1;
}
} else {
bb_error_msg("unrecognized file '%s' with mode %x", source, source_stat.st_mode);
return -1;
}
preserve_mode_ugid_time:
if (flags & FILEUTILS_PRESERVE_STATUS
/* Cannot happen: */
/* && !(flags & (FILEUTILS_MAKE_SOFTLINK|FILEUTILS_MAKE_HARDLINK)) */
) {
struct timeval times[2];
times[1].tv_sec = times[0].tv_sec = source_stat.st_mtime;
times[1].tv_usec = times[0].tv_usec = 0;
/* BTW, utimes sets usec-precision time - just FYI */
if (utimes(dest, times) < 0)
bb_perror_msg("can't preserve %s of '%s'", "times", dest);
if (chown(dest, source_stat.st_uid, source_stat.st_gid) < 0) {
source_stat.st_mode &= ~(S_ISUID | S_ISGID);
bb_perror_msg("can't preserve %s of '%s'", "ownership", dest);
}
if (chmod(dest, source_stat.st_mode) < 0)
bb_perror_msg("can't preserve %s of '%s'", "permissions", dest);
}
verb_and_exit:
if (flags & FILEUTILS_VERBOSE) {
printf("'%s' -> '%s'\n", source, dest);
}
return retval;
}