[Toybox] [PATCH] cpio: Implement -u (copy unconditionally)
enh
enh at google.com
Wed Feb 24 10:17:59 PST 2021
ping?
On Sun, Feb 14, 2021 at 5:13 AM Yi-Yo Chiang via Toybox <
toybox at lists.landley.net> wrote:
> If -u is specified, then replace any existing files or directories.
>
> If -u is not specified and the path to be inflated already exist, then
> report EEXIST error. This behaves slightly different from GNU cpio, as
> GNU cpio checks the timestamp and replaces when the timestamp of the
> existing file is older than the one from the archive. This still
> conforms to SUSv2 as it doesn't define how to behave when -u is not
> specified.
>
> There is an exception, if we are creating an existing directory, then
> don't report any error or try to rmdir() the directory as we can
> "create" the directory by chmod() / chown() the existing one.
>
> ---
> tests/cpio.test | 16 ++++++++++++++++
> toys/posix/cpio.c | 46 ++++++++++++++++++++++++++++++++++++----------
> 2 files changed, 52 insertions(+), 10 deletions(-)
>
> diff --git a/tests/cpio.test b/tests/cpio.test
> index 6ab3665a..7e2955a1 100755
> --- a/tests/cpio.test
> +++ b/tests/cpio.test
> @@ -42,4 +42,20 @@ touch a; chmod a-rwx a; ln -s a/cant b
> toyonly testing "archives unreadable empty files" "cpio -o -H newc|cpio
> -it" "b\na\n" "" "b\na\n"
> chmod u+rw a; rm -f a b
>
> +mkdir a
> +echo "old" >a/b
> +echo "a/b" | cpio -o -H newc >a.cpio
> +rm -rf a
> +testing "-i doesn't create leading directories" "cpio -i <a.cpio
> 2>/dev/null; [ -e a ] || echo yes" "yes\n" "" ""
> +rm -rf a
> +testing "-id creates leading directories" "cpio -id <a.cpio && cat a/b"
> "old\n" "" ""
> +rm -rf a a.cpio
>
> +mkdir a
> +echo "old" >a/b
> +find a | cpio -o -H newc >a.cpio
> +testing "-i keeps existing files" "echo new >a/b && cpio -i <a.cpio
> 2>/dev/null; cat a/b" "new\n" "" ""
> +testing "-id keeps existing files" "echo new >a/b && cpio -id <a.cpio
> 2>/dev/null; cat a/b" "new\n" "" ""
> +testing "-iu replaces existing files; no error" "echo new >a/b && cpio
> -iu <a.cpio && cat a/b" "old\n" "" ""
> +testing "-idu replaces existing files; no error" "echo new >a/b && cpio
> -idu <a.cpio && cat a/b" "old\n" "" ""
> +rm -rf a a.cpio
> diff --git a/toys/posix/cpio.c b/toys/posix/cpio.c
> index 31c777c9..795f890c 100644
> --- a/toys/posix/cpio.c
> +++ b/toys/posix/cpio.c
> @@ -22,7 +22,7 @@ config CPIO
> default y
> help
> usage: cpio -{o|t|i|p DEST} [-v] [--verbose] [-F FILE]
> [--no-preserve-owner]
> - [ignored: -mdu -H newc]
> + [ignored: -m -H newc]
>
> Copy files into and out of a "newc" format cpio archive.
>
> @@ -32,6 +32,7 @@ config CPIO
> -o Create archive (stdin=list of files, stdout=archive)
> -t Test files (list only, stdin=archive, stdout=list of files)
> -d Create directories if needed
> + -u Copy unconditionally
> -v Verbose
> --no-preserve-owner (don't set ownership during extract)
> */
> @@ -113,7 +114,8 @@ void cpio_main(void)
> if (FLAG(i) || FLAG(t)) for (;;) {
> char *name, *tofree, *data;
> unsigned size, mode, uid, gid, timestamp;
> - int test = FLAG(t), err = 0;
> + int test = FLAG(t), err = 0, exist = 0;
> + struct stat st;
>
> // Read header and name.
> if (!(size =readall(afd, toybuf, 110))) break;
> @@ -137,25 +139,50 @@ void cpio_main(void)
> // (This output is unaffected by --quiet.)
> if (FLAG(t) || FLAG(v)) puts(name);
>
> - if (!test && FLAG(d) && strrchr(name, '/') && mkpath(name)) {
> + if (!test) exist = !lstat(name, &st);
> +
> + // Create leading directories if |name| doesn't exist.
> + if (!test && !exist && FLAG(d) && strrchr(name, '/') && mkpath(name))
> {
> perror_msg("mkpath '%s'", name);
> test++;
> }
>
> + // Don't report error or try to rmdir(name) if we want to mkdir(name)
> later.
> + if (!test && exist && !(S_ISDIR(st.st_mode) && S_ISDIR(mode))) {
> + if (!FLAG(u)) {
> + errno = EEXIST;
> + perror_msg_raw(name);
> + test++;
> + } else if (S_ISDIR(st.st_mode) ? rmdir(name) : unlink(name)) {
> + perror_msg("remove '%s'", name);
> + test++;
> + } else {
> + exist = 0;
> + }
> + }
> +
> // Consume entire record even if it couldn't create file, so we're
> // properly aligned with next file.
>
> if (S_ISDIR(mode)) {
> - if (!test) err = mkdir(name, mode);
> + if (!test) {
> + // If |name| already exist as a directory, then just do a chmod()
> to fix
> + // up the directory permissions.
> + if (!exist) err = mkdir(name, mode);
> + else if (S_ISDIR(st.st_mode)) err = chmod(name, mode);
> + else err = errno = EEXIST;
> + }
> } else if (S_ISLNK(mode)) {
> data = strpad(afd, size, 0);
> - if (!test) err = symlink(data, name);
> + if (!test) {
> + err = symlink(data, name);
> + // Can't get a filehandle to a symlink, so do special chown
> + if (!err && !geteuid() && !FLAG(no_preserve_owner))
> + err = lchown(name, uid, gid);
> + }
> free(data);
> - // Can't get a filehandle to a symlink, so do special chown
> - if (!err && !geteuid() && !FLAG(no_preserve_owner))
> - err = lchown(name, uid, gid);
> } else if (S_ISREG(mode)) {
> - int fd = test ? 0 : open(name, O_CREAT|O_WRONLY|O_TRUNC|O_NOFOLLOW,
> mode);
> + int fd = test ? 0 : open(name, O_CREAT|O_EXCL|O_WRONLY|O_NOFOLLOW,
> mode);
>
> // If write fails, we still need to read/discard data to continue
> with
> // archive. Since doing so overwrites errno, report error now
> @@ -197,7 +224,6 @@ void cpio_main(void)
> && !FLAG(no_preserve_owner))
> {
> int fd = open(name, O_RDONLY|O_NOFOLLOW);
> - struct stat st;
>
> if (fd != -1 && !fstat(fd, &st) && (st.st_mode&S_IFMT) ==
> (mode&S_IFMT))
> err = fchown(fd, uid, gid);
> --
> 2.30.0.478.g8a0d178c01-goog
>
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