| 1 | /* vi: set sw=4 ts=4: */
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| 2 | /*
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| 3 | * Mini copy_file implementation for busybox
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| 4 | *
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| 5 | * Copyright (C) 2001 by Matt Kraai <kraai@alumni.carnegiemellon.edu>
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| 6 | * SELinux support by Yuichi Nakamura <ynakam@hitachisoft.jp>
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| 7 | *
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| 8 | * Licensed under GPLv2 or later, see file LICENSE in this source tree.
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| 9 | */
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| 10 | #include "libbb.h"
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| 11 |
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| 12 | // FEATURE_NON_POSIX_CP:
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| 13 | //
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| 14 | // POSIX: if exists and -i, ask (w/o -i assume yes).
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| 15 | // Then open w/o EXCL (yes, not unlink!).
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| 16 | // If open still fails and -f, try unlink, then try open again.
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| 17 | // Result: a mess:
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| 18 | // If dest is a (sym)link, we overwrite link destination!
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| 19 | // (or fail, if it points to dir/nonexistent location/etc).
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| 20 | // This is strange, but POSIX-correct.
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| 21 | // coreutils cp has --remove-destination to override this...
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| 22 |
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| 23 | /* Called if open of destination, link creation etc fails.
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| 24 | * errno must be set to relevant value ("why we cannot create dest?")
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| 25 | * to give reasonable error message */
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| 26 | static int ask_and_unlink(const char *dest, int flags)
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| 27 | {
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| 28 | int e = errno;
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| 29 |
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| 30 | #if !ENABLE_FEATURE_NON_POSIX_CP
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| 31 | if (!(flags & (FILEUTILS_FORCE|FILEUTILS_INTERACTIVE))) {
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| 32 | /* Either it exists, or the *path* doesnt exist */
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| 33 | bb_perror_msg("can't create '%s'", dest);
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| 34 | return -1;
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| 35 | }
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| 36 | #endif
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| 37 | // else: act as if -f is always in effect.
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| 38 | // We don't want "can't create" msg, we want unlink to be done
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| 39 | // (silently unless -i). Why? POSIX cp usually succeeds with
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| 40 | // O_TRUNC open of existing file, and user is left ignorantly happy.
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| 41 | // With above block unconditionally enabled, non-POSIX cp
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| 42 | // will complain a lot more than POSIX one.
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| 43 |
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| 44 | /* TODO: maybe we should do it only if ctty is present? */
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| 45 | if (flags & FILEUTILS_INTERACTIVE) {
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| 46 | // We would not do POSIX insanity. -i asks,
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| 47 | // then _unlinks_ the offender. Presto.
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| 48 | // (No "opening without O_EXCL", no "unlink only if -f")
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| 49 | // Or else we will end up having 3 open()s!
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| 50 | fprintf(stderr, "%s: overwrite '%s'? ", applet_name, dest);
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| 51 | if (!bb_ask_confirmation())
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| 52 | return 0; /* not allowed to overwrite */
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| 53 | }
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| 54 | if (unlink(dest) < 0) {
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| 55 | #if ENABLE_FEATURE_VERBOSE_CP_MESSAGE
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| 56 | if (e == errno && e == ENOENT) {
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| 57 | /* e == ENOTDIR is similar: path has non-dir component,
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| 58 | * but in this case we don't even reach copy_file() */
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| 59 | bb_error_msg("can't create '%s': Path does not exist", dest);
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| 60 | return -1; /* error */
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| 61 | }
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| 62 | #endif
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| 63 | errno = e; /* do not use errno from unlink */
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| 64 | bb_perror_msg("can't create '%s'", dest);
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| 65 | return -1; /* error */
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| 66 | }
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| 67 | return 1; /* ok (to try again) */
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| 68 | }
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| 69 |
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| 70 | /* Return:
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| 71 | * -1 error, copy not made
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| 72 | * 0 copy is made or user answered "no" in interactive mode
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| 73 | * (failures to preserve mode/owner/times are not reported in exit code)
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| 74 | */
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| 75 | int FAST_FUNC copy_file(const char *source, const char *dest, int flags)
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| 76 | {
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| 77 | /* This is a recursive function, try to minimize stack usage */
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| 78 | /* NB: each struct stat is ~100 bytes */
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| 79 | struct stat source_stat;
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| 80 | struct stat dest_stat;
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| 81 | signed char retval = 0;
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| 82 | signed char dest_exists = 0;
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| 83 | signed char ovr;
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| 84 |
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| 85 | /* Inverse of cp -d ("cp without -d") */
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| 86 | #define FLAGS_DEREF (flags & (FILEUTILS_DEREFERENCE + FILEUTILS_DEREFERENCE_L0))
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| 87 |
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| 88 | if ((FLAGS_DEREF ? stat : lstat)(source, &source_stat) < 0) {
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| 89 | /* This may be a dangling symlink.
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| 90 | * Making [sym]links to dangling symlinks works, so... */
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| 91 | if (flags & (FILEUTILS_MAKE_SOFTLINK|FILEUTILS_MAKE_HARDLINK))
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| 92 | goto make_links;
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| 93 | bb_perror_msg("can't stat '%s'", source);
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| 94 | return -1;
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| 95 | }
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| 96 |
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| 97 | if (lstat(dest, &dest_stat) < 0) {
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| 98 | if (errno != ENOENT) {
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| 99 | bb_perror_msg("can't stat '%s'", dest);
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| 100 | return -1;
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| 101 | }
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| 102 | } else {
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| 103 | if (source_stat.st_dev == dest_stat.st_dev
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| 104 | && source_stat.st_ino == dest_stat.st_ino
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| 105 | ) {
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| 106 | bb_error_msg("'%s' and '%s' are the same file", source, dest);
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| 107 | return -1;
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| 108 | }
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| 109 | dest_exists = 1;
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| 110 | }
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| 111 |
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| 112 | #if ENABLE_SELINUX
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| 113 | if ((flags & FILEUTILS_PRESERVE_SECURITY_CONTEXT) && is_selinux_enabled() > 0) {
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| 114 | security_context_t con;
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| 115 | if (lgetfilecon(source, &con) >= 0) {
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| 116 | if (setfscreatecon(con) < 0) {
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| 117 | bb_perror_msg("can't set setfscreatecon %s", con);
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| 118 | freecon(con);
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| 119 | return -1;
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| 120 | }
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| 121 | } else if (errno == ENOTSUP || errno == ENODATA) {
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| 122 | setfscreatecon_or_die(NULL);
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| 123 | } else {
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| 124 | bb_perror_msg("can't lgetfilecon %s", source);
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| 125 | return -1;
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| 126 | }
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| 127 | }
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| 128 | #endif
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| 129 |
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| 130 | if (S_ISDIR(source_stat.st_mode)) {
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| 131 | DIR *dp;
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| 132 | const char *tp;
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| 133 | struct dirent *d;
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| 134 | mode_t saved_umask = 0;
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| 135 |
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| 136 | if (!(flags & FILEUTILS_RECUR)) {
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| 137 | bb_error_msg("omitting directory '%s'", source);
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| 138 | return -1;
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| 139 | }
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| 140 |
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| 141 | /* Did we ever create source ourself before? */
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| 142 | tp = is_in_ino_dev_hashtable(&source_stat);
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| 143 | if (tp) {
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| 144 | /* We did! it's a recursion! man the lifeboats... */
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| 145 | bb_error_msg("recursion detected, omitting directory '%s'",
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| 146 | source);
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| 147 | return -1;
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| 148 | }
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| 149 |
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| 150 | /* Create DEST */
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| 151 | if (dest_exists) {
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| 152 | if (!S_ISDIR(dest_stat.st_mode)) {
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| 153 | bb_error_msg("target '%s' is not a directory", dest);
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| 154 | return -1;
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| 155 | }
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| 156 | /* race here: user can substitute a symlink between
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| 157 | * this check and actual creation of files inside dest */
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| 158 | } else {
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| 159 | mode_t mode;
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| 160 | saved_umask = umask(0);
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| 161 |
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| 162 | mode = source_stat.st_mode;
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| 163 | if (!(flags & FILEUTILS_PRESERVE_STATUS))
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| 164 | mode = source_stat.st_mode & ~saved_umask;
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| 165 | /* Allow owner to access new dir (at least for now) */
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| 166 | mode |= S_IRWXU;
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| 167 | if (mkdir(dest, mode) < 0) {
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| 168 | umask(saved_umask);
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| 169 | bb_perror_msg("can't create directory '%s'", dest);
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| 170 | return -1;
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| 171 | }
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| 172 | umask(saved_umask);
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| 173 | /* need stat info for add_to_ino_dev_hashtable */
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| 174 | if (lstat(dest, &dest_stat) < 0) {
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| 175 | bb_perror_msg("can't stat '%s'", dest);
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| 176 | return -1;
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| 177 | }
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| 178 | }
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| 179 | /* remember (dev,inode) of each created dir.
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| 180 | * NULL: name is not remembered */
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| 181 | add_to_ino_dev_hashtable(&dest_stat, NULL);
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| 182 |
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| 183 | /* Recursively copy files in SOURCE */
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| 184 | dp = opendir(source);
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| 185 | if (dp == NULL) {
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| 186 | retval = -1;
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| 187 | goto preserve_mode_ugid_time;
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| 188 | }
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| 189 |
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| 190 | while ((d = readdir(dp)) != NULL) {
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| 191 | char *new_source, *new_dest;
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| 192 |
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| 193 | new_source = concat_subpath_file(source, d->d_name);
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| 194 | if (new_source == NULL)
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| 195 | continue;
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| 196 | new_dest = concat_path_file(dest, d->d_name);
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| 197 | if (copy_file(new_source, new_dest, flags & ~FILEUTILS_DEREFERENCE_L0) < 0)
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| 198 | retval = -1;
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| 199 | free(new_source);
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| 200 | free(new_dest);
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| 201 | }
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| 202 | closedir(dp);
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| 203 |
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| 204 | if (!dest_exists
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| 205 | && chmod(dest, source_stat.st_mode & ~saved_umask) < 0
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| 206 | ) {
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| 207 | bb_perror_msg("can't preserve %s of '%s'", "permissions", dest);
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| 208 | /* retval = -1; - WRONG! copy *WAS* made */
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| 209 | }
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| 210 | goto preserve_mode_ugid_time;
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| 211 | }
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| 212 |
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| 213 | if (flags & (FILEUTILS_MAKE_SOFTLINK|FILEUTILS_MAKE_HARDLINK)) {
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| 214 | int (*lf)(const char *oldpath, const char *newpath);
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| 215 | make_links:
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| 216 | /* Hmm... maybe
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| 217 | * if (DEREF && MAKE_SOFTLINK) source = realpath(source) ?
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| 218 | * (but realpath returns NULL on dangling symlinks...) */
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| 219 | lf = (flags & FILEUTILS_MAKE_SOFTLINK) ? symlink : link;
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| 220 | if (lf(source, dest) < 0) {
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| 221 | ovr = ask_and_unlink(dest, flags);
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| 222 | if (ovr <= 0)
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| 223 | return ovr;
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| 224 | if (lf(source, dest) < 0) {
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| 225 | bb_perror_msg("can't create link '%s'", dest);
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| 226 | return -1;
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| 227 | }
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| 228 | }
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| 229 | /* _Not_ jumping to preserve_mode_ugid_time:
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| 230 | * (sym)links don't have those */
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| 231 | return 0;
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| 232 | }
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| 233 |
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| 234 | if (/* "cp thing1 thing2" without -R: just open and read() from thing1 */
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| 235 | !(flags & FILEUTILS_RECUR)
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| 236 | /* "cp [-opts] regular_file thing2" */
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| 237 | || S_ISREG(source_stat.st_mode)
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| 238 | /* DEREF uses stat, which never returns S_ISLNK() == true.
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| 239 | * So the below is never true: */
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| 240 | /* || (FLAGS_DEREF && S_ISLNK(source_stat.st_mode)) */
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| 241 | ) {
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| 242 | int src_fd;
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| 243 | int dst_fd;
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| 244 | mode_t new_mode;
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| 245 |
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| 246 | if (!FLAGS_DEREF && S_ISLNK(source_stat.st_mode)) {
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| 247 | /* "cp -d symlink dst": create a link */
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| 248 | goto dont_cat;
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| 249 | }
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| 250 |
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| 251 | if (ENABLE_FEATURE_PRESERVE_HARDLINKS && !FLAGS_DEREF) {
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| 252 | const char *link_target;
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| 253 | link_target = is_in_ino_dev_hashtable(&source_stat);
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| 254 | if (link_target) {
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| 255 | if (link(link_target, dest) < 0) {
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| 256 | ovr = ask_and_unlink(dest, flags);
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| 257 | if (ovr <= 0)
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| 258 | return ovr;
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| 259 | if (link(link_target, dest) < 0) {
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| 260 | bb_perror_msg("can't create link '%s'", dest);
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| 261 | return -1;
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| 262 | }
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| 263 | }
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| 264 | return 0;
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| 265 | }
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| 266 | add_to_ino_dev_hashtable(&source_stat, dest);
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| 267 | }
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| 268 |
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| 269 | src_fd = open_or_warn(source, O_RDONLY);
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| 270 | if (src_fd < 0)
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| 271 | return -1;
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| 272 |
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| 273 | /* Do not try to open with weird mode fields */
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| 274 | new_mode = source_stat.st_mode;
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| 275 | if (!S_ISREG(source_stat.st_mode))
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| 276 | new_mode = 0666;
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| 277 |
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| 278 | // POSIX way is a security problem versus (sym)link attacks
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| 279 | if (!ENABLE_FEATURE_NON_POSIX_CP) {
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| 280 | dst_fd = open(dest, O_WRONLY|O_CREAT|O_TRUNC, new_mode);
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| 281 | } else { /* safe way: */
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| 282 | dst_fd = open(dest, O_WRONLY|O_CREAT|O_EXCL, new_mode);
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| 283 | }
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| 284 | if (dst_fd == -1) {
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| 285 | ovr = ask_and_unlink(dest, flags);
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| 286 | if (ovr <= 0) {
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| 287 | close(src_fd);
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| 288 | return ovr;
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| 289 | }
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| 290 | /* It shouldn't exist. If it exists, do not open (symlink attack?) */
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| 291 | dst_fd = open3_or_warn(dest, O_WRONLY|O_CREAT|O_EXCL, new_mode);
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| 292 | if (dst_fd < 0) {
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| 293 | close(src_fd);
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| 294 | return -1;
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| 295 | }
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| 296 | }
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| 297 |
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| 298 | #if ENABLE_SELINUX
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| 299 | if ((flags & (FILEUTILS_PRESERVE_SECURITY_CONTEXT|FILEUTILS_SET_SECURITY_CONTEXT))
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| 300 | && is_selinux_enabled() > 0
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| 301 | ) {
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| 302 | security_context_t con;
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| 303 | if (getfscreatecon(&con) == -1) {
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| 304 | bb_perror_msg("getfscreatecon");
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| 305 | return -1;
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| 306 | }
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| 307 | if (con) {
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| 308 | if (setfilecon(dest, con) == -1) {
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| 309 | bb_perror_msg("setfilecon:%s,%s", dest, con);
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| 310 | freecon(con);
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| 311 | return -1;
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| 312 | }
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| 313 | freecon(con);
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| 314 | }
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| 315 | }
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| 316 | #endif
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| 317 | if (bb_copyfd_eof(src_fd, dst_fd) == -1)
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| 318 | retval = -1;
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| 319 | /* Careful with writing... */
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| 320 | if (close(dst_fd) < 0) {
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| 321 | bb_perror_msg("error writing to '%s'", dest);
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| 322 | retval = -1;
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| 323 | }
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| 324 | /* ...but read size is already checked by bb_copyfd_eof */
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| 325 | close(src_fd);
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| 326 | /* "cp /dev/something new_file" should not
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| 327 | * copy mode of /dev/something */
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| 328 | if (!S_ISREG(source_stat.st_mode))
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| 329 | return retval;
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| 330 | goto preserve_mode_ugid_time;
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| 331 | }
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| 332 | dont_cat:
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| 333 |
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| 334 | /* Source is a symlink or a special file */
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| 335 | /* We are lazy here, a bit lax with races... */
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| 336 | if (dest_exists) {
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| 337 | errno = EEXIST;
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| 338 | ovr = ask_and_unlink(dest, flags);
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| 339 | if (ovr <= 0)
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| 340 | return ovr;
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| 341 | }
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| 342 | if (S_ISLNK(source_stat.st_mode)) {
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| 343 | char *lpath = xmalloc_readlink_or_warn(source);
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| 344 | if (lpath) {
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| 345 | int r = symlink(lpath, dest);
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| 346 | free(lpath);
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| 347 | if (r < 0) {
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| 348 | bb_perror_msg("can't create symlink '%s'", dest);
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| 349 | return -1;
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| 350 | }
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| 351 | if (flags & FILEUTILS_PRESERVE_STATUS)
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| 352 | if (lchown(dest, source_stat.st_uid, source_stat.st_gid) < 0)
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| 353 | bb_perror_msg("can't preserve %s of '%s'", "ownership", dest);
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| 354 | }
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| 355 | /* _Not_ jumping to preserve_mode_ugid_time:
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| 356 | * symlinks don't have those */
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| 357 | return 0;
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| 358 | }
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| 359 | if (S_ISBLK(source_stat.st_mode) || S_ISCHR(source_stat.st_mode)
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| 360 | || S_ISSOCK(source_stat.st_mode) || S_ISFIFO(source_stat.st_mode)
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| 361 | ) {
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| 362 | if (mknod(dest, source_stat.st_mode, source_stat.st_rdev) < 0) {
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| 363 | bb_perror_msg("can't create '%s'", dest);
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| 364 | return -1;
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| 365 | }
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| 366 | } else {
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| 367 | bb_error_msg("unrecognized file '%s' with mode %x", source, source_stat.st_mode);
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| 368 | return -1;
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| 369 | }
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| 370 |
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| 371 | preserve_mode_ugid_time:
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| 372 |
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| 373 | if (flags & FILEUTILS_PRESERVE_STATUS
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| 374 | /* Cannot happen: */
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| 375 | /* && !(flags & (FILEUTILS_MAKE_SOFTLINK|FILEUTILS_MAKE_HARDLINK)) */
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| 376 | ) {
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| 377 | struct timeval times[2];
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| 378 |
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| 379 | times[1].tv_sec = times[0].tv_sec = source_stat.st_mtime;
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| 380 | times[1].tv_usec = times[0].tv_usec = 0;
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| 381 | /* BTW, utimes sets usec-precision time - just FYI */
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| 382 | if (utimes(dest, times) < 0)
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| 383 | bb_perror_msg("can't preserve %s of '%s'", "times", dest);
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| 384 | if (chown(dest, source_stat.st_uid, source_stat.st_gid) < 0) {
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| 385 | source_stat.st_mode &= ~(S_ISUID | S_ISGID);
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| 386 | bb_perror_msg("can't preserve %s of '%s'", "ownership", dest);
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| 387 | }
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| 388 | if (chmod(dest, source_stat.st_mode) < 0)
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| 389 | bb_perror_msg("can't preserve %s of '%s'", "permissions", dest);
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| 390 | }
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| 391 |
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| 392 | return retval;
|
|---|
| 393 | }
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|---|
