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-rw-r--r--src/basic/copy.c1237
1 files changed, 1237 insertions, 0 deletions
diff --git a/src/basic/copy.c b/src/basic/copy.c
new file mode 100644
index 0000000..6a9c3a3
--- /dev/null
+++ b/src/basic/copy.c
@@ -0,0 +1,1237 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <errno.h>
+#include <fcntl.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/sendfile.h>
+#include <sys/xattr.h>
+#include <unistd.h>
+
+#include "alloc-util.h"
+#include "btrfs-util.h"
+#include "chattr-util.h"
+#include "copy.h"
+#include "dirent-util.h"
+#include "fd-util.h"
+#include "fileio.h"
+#include "fs-util.h"
+#include "io-util.h"
+#include "macro.h"
+#include "missing_syscall.h"
+#include "mountpoint-util.h"
+#include "nulstr-util.h"
+#include "rm-rf.h"
+#include "selinux-util.h"
+#include "stat-util.h"
+#include "stdio-util.h"
+#include "string-util.h"
+#include "strv.h"
+#include "time-util.h"
+#include "tmpfile-util.h"
+#include "umask-util.h"
+#include "user-util.h"
+#include "xattr-util.h"
+
+#define COPY_BUFFER_SIZE (16U*1024U)
+
+/* A safety net for descending recursively into file system trees to copy. On Linux PATH_MAX is 4096, which means the
+ * deepest valid path one can build is around 2048, which we hence use as a safety net here, to not spin endlessly in
+ * case of bind mount cycles and suchlike. */
+#define COPY_DEPTH_MAX 2048U
+
+static ssize_t try_copy_file_range(
+ int fd_in, loff_t *off_in,
+ int fd_out, loff_t *off_out,
+ size_t len,
+ unsigned flags) {
+
+ static int have = -1;
+ ssize_t r;
+
+ if (have == 0)
+ return -ENOSYS;
+
+ r = copy_file_range(fd_in, off_in, fd_out, off_out, len, flags);
+ if (have < 0)
+ have = r >= 0 || errno != ENOSYS;
+ if (r < 0)
+ return -errno;
+
+ return r;
+}
+
+enum {
+ FD_IS_NO_PIPE,
+ FD_IS_BLOCKING_PIPE,
+ FD_IS_NONBLOCKING_PIPE,
+};
+
+static int fd_is_nonblock_pipe(int fd) {
+ struct stat st;
+ int flags;
+
+ /* Checks whether the specified file descriptor refers to a pipe, and if so if O_NONBLOCK is set. */
+
+ if (fstat(fd, &st) < 0)
+ return -errno;
+
+ if (!S_ISFIFO(st.st_mode))
+ return FD_IS_NO_PIPE;
+
+ flags = fcntl(fd, F_GETFL);
+ if (flags < 0)
+ return -errno;
+
+ return FLAGS_SET(flags, O_NONBLOCK) ? FD_IS_NONBLOCKING_PIPE : FD_IS_BLOCKING_PIPE;
+}
+
+static int sigint_pending(void) {
+ sigset_t ss;
+
+ assert_se(sigemptyset(&ss) >= 0);
+ assert_se(sigaddset(&ss, SIGINT) >= 0);
+
+ if (sigtimedwait(&ss, NULL, &(struct timespec) { 0, 0 }) < 0) {
+ if (errno == EAGAIN)
+ return false;
+
+ return -errno;
+ }
+
+ return true;
+}
+
+int copy_bytes_full(
+ int fdf, int fdt,
+ uint64_t max_bytes,
+ CopyFlags copy_flags,
+ void **ret_remains,
+ size_t *ret_remains_size,
+ copy_progress_bytes_t progress,
+ void *userdata) {
+
+ bool try_cfr = true, try_sendfile = true, try_splice = true;
+ int r, nonblock_pipe = -1;
+ size_t m = SSIZE_MAX; /* that is the maximum that sendfile and c_f_r accept */
+
+ assert(fdf >= 0);
+ assert(fdt >= 0);
+
+ /* Tries to copy bytes from the file descriptor 'fdf' to 'fdt' in the smartest possible way. Copies a maximum
+ * of 'max_bytes', which may be specified as UINT64_MAX, in which no maximum is applied. Returns negative on
+ * error, zero if EOF is hit before the bytes limit is hit and positive otherwise. If the copy fails for some
+ * reason but we read but didn't yet write some data an ret_remains/ret_remains_size is not NULL, then it will
+ * be initialized with an allocated buffer containing this "remaining" data. Note that these two parameters are
+ * initialized with a valid buffer only on failure and only if there's actually data already read. Otherwise
+ * these parameters if non-NULL are set to NULL. */
+
+ if (ret_remains)
+ *ret_remains = NULL;
+ if (ret_remains_size)
+ *ret_remains_size = 0;
+
+ /* Try btrfs reflinks first. This only works on regular, seekable files, hence let's check the file offsets of
+ * source and destination first. */
+ if ((copy_flags & COPY_REFLINK)) {
+ off_t foffset;
+
+ foffset = lseek(fdf, 0, SEEK_CUR);
+ if (foffset >= 0) {
+ off_t toffset;
+
+ toffset = lseek(fdt, 0, SEEK_CUR);
+ if (toffset >= 0) {
+
+ if (foffset == 0 && toffset == 0 && max_bytes == UINT64_MAX)
+ r = btrfs_reflink(fdf, fdt); /* full file reflink */
+ else
+ r = btrfs_clone_range(fdf, foffset, fdt, toffset, max_bytes == UINT64_MAX ? 0 : max_bytes); /* partial reflink */
+ if (r >= 0) {
+ off_t t;
+
+ /* This worked, yay! Now — to be fully correct — let's adjust the file pointers */
+ if (max_bytes == UINT64_MAX) {
+
+ /* We cloned to the end of the source file, let's position the read
+ * pointer there, and query it at the same time. */
+ t = lseek(fdf, 0, SEEK_END);
+ if (t < 0)
+ return -errno;
+ if (t < foffset)
+ return -ESPIPE;
+
+ /* Let's adjust the destination file write pointer by the same number
+ * of bytes. */
+ t = lseek(fdt, toffset + (t - foffset), SEEK_SET);
+ if (t < 0)
+ return -errno;
+
+ return 0; /* we copied the whole thing, hence hit EOF, return 0 */
+ } else {
+ t = lseek(fdf, foffset + max_bytes, SEEK_SET);
+ if (t < 0)
+ return -errno;
+
+ t = lseek(fdt, toffset + max_bytes, SEEK_SET);
+ if (t < 0)
+ return -errno;
+
+ return 1; /* we copied only some number of bytes, which worked, but this means we didn't hit EOF, return 1 */
+ }
+ }
+ }
+ }
+ }
+
+ for (;;) {
+ ssize_t n;
+
+ if (max_bytes <= 0)
+ return 1; /* return > 0 if we hit the max_bytes limit */
+
+ if (FLAGS_SET(copy_flags, COPY_SIGINT)) {
+ r = sigint_pending();
+ if (r < 0)
+ return r;
+ if (r > 0)
+ return -EINTR;
+ }
+
+ if (max_bytes != UINT64_MAX && m > max_bytes)
+ m = max_bytes;
+
+ /* First try copy_file_range(), unless we already tried */
+ if (try_cfr) {
+ n = try_copy_file_range(fdf, NULL, fdt, NULL, m, 0u);
+ if (n < 0) {
+ if (!IN_SET(n, -EINVAL, -ENOSYS, -EXDEV, -EBADF))
+ return n;
+
+ try_cfr = false;
+ /* use fallback below */
+ } else if (n == 0) /* EOF */
+ break;
+ else
+ /* Success! */
+ goto next;
+ }
+
+ /* First try sendfile(), unless we already tried */
+ if (try_sendfile) {
+ n = sendfile(fdt, fdf, NULL, m);
+ if (n < 0) {
+ if (!IN_SET(errno, EINVAL, ENOSYS))
+ return -errno;
+
+ try_sendfile = false;
+ /* use fallback below */
+ } else if (n == 0) /* EOF */
+ break;
+ else
+ /* Success! */
+ goto next;
+ }
+
+ /* Then try splice, unless we already tried. */
+ if (try_splice) {
+
+ /* splice()'s asynchronous I/O support is a bit weird. When it encounters a pipe file
+ * descriptor, then it will ignore its O_NONBLOCK flag and instead only honour the
+ * SPLICE_F_NONBLOCK flag specified in its flag parameter. Let's hide this behaviour here, and
+ * check if either of the specified fds are a pipe, and if so, let's pass the flag
+ * automatically, depending on O_NONBLOCK being set.
+ *
+ * Here's a twist though: when we use it to move data between two pipes of which one has
+ * O_NONBLOCK set and the other has not, then we have no individual control over O_NONBLOCK
+ * behaviour. Hence in that case we can't use splice() and still guarantee systematic
+ * O_NONBLOCK behaviour, hence don't. */
+
+ if (nonblock_pipe < 0) {
+ int a, b;
+
+ /* Check if either of these fds is a pipe, and if so non-blocking or not */
+ a = fd_is_nonblock_pipe(fdf);
+ if (a < 0)
+ return a;
+
+ b = fd_is_nonblock_pipe(fdt);
+ if (b < 0)
+ return b;
+
+ if ((a == FD_IS_NO_PIPE && b == FD_IS_NO_PIPE) ||
+ (a == FD_IS_BLOCKING_PIPE && b == FD_IS_NONBLOCKING_PIPE) ||
+ (a == FD_IS_NONBLOCKING_PIPE && b == FD_IS_BLOCKING_PIPE))
+
+ /* splice() only works if one of the fds is a pipe. If neither is, let's skip
+ * this step right-away. As mentioned above, if one of the two fds refers to a
+ * blocking pipe and the other to a non-blocking pipe, we can't use splice()
+ * either, hence don't try either. This hence means we can only use splice() if
+ * either only one of the two fds is a pipe, or if both are pipes with the same
+ * nonblocking flag setting. */
+
+ try_splice = false;
+ else
+ nonblock_pipe = a == FD_IS_NONBLOCKING_PIPE || b == FD_IS_NONBLOCKING_PIPE;
+ }
+ }
+
+ if (try_splice) {
+ n = splice(fdf, NULL, fdt, NULL, m, nonblock_pipe ? SPLICE_F_NONBLOCK : 0);
+ if (n < 0) {
+ if (!IN_SET(errno, EINVAL, ENOSYS))
+ return -errno;
+
+ try_splice = false;
+ /* use fallback below */
+ } else if (n == 0) /* EOF */
+ break;
+ else
+ /* Success! */
+ goto next;
+ }
+
+ /* As a fallback just copy bits by hand */
+ {
+ uint8_t buf[MIN(m, COPY_BUFFER_SIZE)], *p = buf;
+ ssize_t z;
+
+ n = read(fdf, buf, sizeof buf);
+ if (n < 0)
+ return -errno;
+ if (n == 0) /* EOF */
+ break;
+
+ z = (size_t) n;
+ do {
+ ssize_t k;
+
+ k = write(fdt, p, z);
+ if (k < 0) {
+ r = -errno;
+
+ if (ret_remains) {
+ void *copy;
+
+ copy = memdup(p, z);
+ if (!copy)
+ return -ENOMEM;
+
+ *ret_remains = copy;
+ }
+
+ if (ret_remains_size)
+ *ret_remains_size = z;
+
+ return r;
+ }
+
+ assert(k <= z);
+ z -= k;
+ p += k;
+ } while (z > 0);
+ }
+
+ next:
+ if (progress) {
+ r = progress(n, userdata);
+ if (r < 0)
+ return r;
+ }
+
+ if (max_bytes != (uint64_t) -1) {
+ assert(max_bytes >= (uint64_t) n);
+ max_bytes -= n;
+ }
+
+ /* sendfile accepts at most SSIZE_MAX-offset bytes to copy,
+ * so reduce our maximum by the amount we already copied,
+ * but don't go below our copy buffer size, unless we are
+ * close the limit of bytes we are allowed to copy. */
+ m = MAX(MIN(COPY_BUFFER_SIZE, max_bytes), m - n);
+ }
+
+ return 0; /* return 0 if we hit EOF earlier than the size limit */
+}
+
+static int fd_copy_symlink(
+ int df,
+ const char *from,
+ const struct stat *st,
+ int dt,
+ const char *to,
+ uid_t override_uid,
+ gid_t override_gid,
+ CopyFlags copy_flags) {
+
+ _cleanup_free_ char *target = NULL;
+ int r;
+
+ assert(from);
+ assert(st);
+ assert(to);
+
+ r = readlinkat_malloc(df, from, &target);
+ if (r < 0)
+ return r;
+
+ if (copy_flags & COPY_MAC_CREATE) {
+ r = mac_selinux_create_file_prepare_at(dt, to, S_IFLNK);
+ if (r < 0)
+ return r;
+ }
+ r = symlinkat(target, dt, to);
+ if (copy_flags & COPY_MAC_CREATE)
+ mac_selinux_create_file_clear();
+ if (r < 0)
+ return -errno;
+
+ if (fchownat(dt, to,
+ uid_is_valid(override_uid) ? override_uid : st->st_uid,
+ gid_is_valid(override_gid) ? override_gid : st->st_gid,
+ AT_SYMLINK_NOFOLLOW) < 0)
+ return -errno;
+
+ return 0;
+}
+
+/* Encapsulates the database we store potential hardlink targets in */
+typedef struct HardlinkContext {
+ int dir_fd; /* An fd to the directory we use as lookup table. Never AT_FDCWD. Lazily created, when
+ * we add the first entry. */
+
+ /* These two fields are used to create the hardlink repository directory above — via
+ * mkdirat(parent_fd, subdir) — and are kept so that we can automatically remove the directory again
+ * when we are done. */
+ int parent_fd; /* Possibly AT_FDCWD */
+ char *subdir;
+} HardlinkContext;
+
+static int hardlink_context_setup(
+ HardlinkContext *c,
+ int dt,
+ const char *to,
+ CopyFlags copy_flags) {
+
+ _cleanup_close_ int dt_copy = -1;
+ int r;
+
+ assert(c);
+ assert(c->dir_fd < 0 && c->dir_fd != AT_FDCWD);
+ assert(c->parent_fd < 0);
+ assert(!c->subdir);
+
+ /* If hardlink recreation is requested we have to maintain a database of inodes that are potential
+ * hardlink sources. Given that generally disk sizes have to be assumed to be larger than what fits
+ * into physical RAM we cannot maintain that database in dynamic memory alone. Here we opt to
+ * maintain it on disk, to simplify things: inside the destination directory we'll maintain a
+ * temporary directory consisting of hardlinks of every inode we copied that might be subject of
+ * hardlinks. We can then use that as hardlink source later on. Yes, this means additional disk IO
+ * but thankfully Linux is optimized for this kind of thing. If this ever becomes a performance
+ * bottleneck we can certainly place an in-memory hash table in front of this, but for the beginning,
+ * let's keep things simple, and just use the disk as lookup table for inodes.
+ *
+ * Note that this should have zero performance impact as long as .n_link of all files copied remains
+ * <= 0, because in that case we will not actually allocate the hardlink inode lookup table directory
+ * on disk (we do so lazily, when the first candidate with .n_link > 1 is seen). This means, in the
+ * common case where hardlinks are not used at all or only for few files the fact that we store the
+ * table on disk shouldn't matter perfomance-wise. */
+
+ if (!FLAGS_SET(copy_flags, COPY_HARDLINKS))
+ return 0;
+
+ if (dt == AT_FDCWD)
+ dt_copy = AT_FDCWD;
+ else if (dt < 0)
+ return -EBADF;
+ else {
+ dt_copy = fcntl(dt, F_DUPFD_CLOEXEC, 3);
+ if (dt_copy < 0)
+ return -errno;
+ }
+
+ r = tempfn_random_child(to, "hardlink", &c->subdir);
+ if (r < 0)
+ return r;
+
+ c->parent_fd = TAKE_FD(dt_copy);
+
+ /* We don't actually create the directory we keep the table in here, that's done on-demand when the
+ * first entry is added, using hardlink_context_realize() below. */
+ return 1;
+}
+
+static int hardlink_context_realize(HardlinkContext *c) {
+ int r;
+
+ if (!c)
+ return 0;
+
+ if (c->dir_fd >= 0) /* Already realized */
+ return 1;
+
+ if (c->parent_fd < 0 && c->parent_fd != AT_FDCWD) /* Not configured */
+ return 0;
+
+ assert(c->subdir);
+
+ if (mkdirat(c->parent_fd, c->subdir, 0700) < 0)
+ return -errno;
+
+ c->dir_fd = openat(c->parent_fd, c->subdir, O_RDONLY|O_DIRECTORY|O_CLOEXEC);
+ if (c->dir_fd < 0) {
+ r = -errno;
+ (void) unlinkat(c->parent_fd, c->subdir, AT_REMOVEDIR);
+ return r;
+ }
+
+ return 1;
+}
+
+static void hardlink_context_destroy(HardlinkContext *c) {
+ int r;
+
+ assert(c);
+
+ /* Automatically remove the hardlink lookup table directory again after we are done. This is used via
+ * _cleanup_() so that we really delete this, even on failure. */
+
+ if (c->dir_fd >= 0) {
+ r = rm_rf_children(TAKE_FD(c->dir_fd), REMOVE_PHYSICAL, NULL); /* consumes dir_fd in all cases, even on failure */
+ if (r < 0)
+ log_debug_errno(r, "Failed to remove hardlink store (%s) contents, ignoring: %m", c->subdir);
+
+ assert(c->parent_fd >= 0 || c->parent_fd == AT_FDCWD);
+ assert(c->subdir);
+
+ if (unlinkat(c->parent_fd, c->subdir, AT_REMOVEDIR) < 0)
+ log_debug_errno(errno, "Failed to remove hardlink store (%s) directory, ignoring: %m", c->subdir);
+ }
+
+ assert_cc(AT_FDCWD < 0);
+ c->parent_fd = safe_close(c->parent_fd);
+
+ c->subdir = mfree(c->subdir);
+}
+
+static int try_hardlink(
+ HardlinkContext *c,
+ const struct stat *st,
+ int dt,
+ const char *to) {
+
+ char dev_ino[DECIMAL_STR_MAX(dev_t)*2 + DECIMAL_STR_MAX(uint64_t) + 4];
+
+ assert(st);
+ assert(dt >= 0 || dt == AT_FDCWD);
+ assert(to);
+
+ if (!c) /* No temporary hardlink directory, don't bother */
+ return 0;
+
+ if (st->st_nlink <= 1) /* Source not hardlinked, don't bother */
+ return 0;
+
+ if (c->dir_fd < 0) /* not yet realized, hence empty */
+ return 0;
+
+ xsprintf(dev_ino, "%u:%u:%" PRIu64, major(st->st_dev), minor(st->st_dev), (uint64_t) st->st_ino);
+ if (linkat(c->dir_fd, dev_ino, dt, to, 0) < 0) {
+ if (errno != ENOENT) /* doesn't exist in store yet */
+ log_debug_errno(errno, "Failed to hardlink %s to %s, ignoring: %m", dev_ino, to);
+ return 0;
+ }
+
+ return 1;
+}
+
+static int memorize_hardlink(
+ HardlinkContext *c,
+ const struct stat *st,
+ int dt,
+ const char *to) {
+
+ char dev_ino[DECIMAL_STR_MAX(dev_t)*2 + DECIMAL_STR_MAX(uint64_t) + 4];
+ int r;
+
+ assert(st);
+ assert(dt >= 0 || dt == AT_FDCWD);
+ assert(to);
+
+ if (!c) /* No temporary hardlink directory, don't bother */
+ return 0;
+
+ if (st->st_nlink <= 1) /* Source not hardlinked, don't bother */
+ return 0;
+
+ r = hardlink_context_realize(c); /* Create the hardlink store lazily */
+ if (r < 0)
+ return r;
+
+ xsprintf(dev_ino, "%u:%u:%" PRIu64, major(st->st_dev), minor(st->st_dev), (uint64_t) st->st_ino);
+ if (linkat(dt, to, c->dir_fd, dev_ino, 0) < 0) {
+ log_debug_errno(errno, "Failed to hardlink %s to %s, ignoring: %m", to, dev_ino);
+ return 0;
+ }
+
+ return 1;
+}
+
+static int fd_copy_regular(
+ int df,
+ const char *from,
+ const struct stat *st,
+ int dt,
+ const char *to,
+ uid_t override_uid,
+ gid_t override_gid,
+ CopyFlags copy_flags,
+ HardlinkContext *hardlink_context,
+ copy_progress_bytes_t progress,
+ void *userdata) {
+
+ _cleanup_close_ int fdf = -1, fdt = -1;
+ struct timespec ts[2];
+ int r, q;
+
+ assert(from);
+ assert(st);
+ assert(to);
+
+ r = try_hardlink(hardlink_context, st, dt, to);
+ if (r < 0)
+ return r;
+ if (r > 0) /* worked! */
+ return 0;
+
+ fdf = openat(df, from, O_RDONLY|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW);
+ if (fdf < 0)
+ return -errno;
+
+ if (copy_flags & COPY_MAC_CREATE) {
+ r = mac_selinux_create_file_prepare_at(dt, to, S_IFREG);
+ if (r < 0)
+ return r;
+ }
+ fdt = openat(dt, to, O_WRONLY|O_CREAT|O_EXCL|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW, st->st_mode & 07777);
+ if (copy_flags & COPY_MAC_CREATE)
+ mac_selinux_create_file_clear();
+ if (fdt < 0)
+ return -errno;
+
+ r = copy_bytes_full(fdf, fdt, (uint64_t) -1, copy_flags, NULL, NULL, progress, userdata);
+ if (r < 0) {
+ (void) unlinkat(dt, to, 0);
+ return r;
+ }
+
+ if (fchown(fdt,
+ uid_is_valid(override_uid) ? override_uid : st->st_uid,
+ gid_is_valid(override_gid) ? override_gid : st->st_gid) < 0)
+ r = -errno;
+
+ if (fchmod(fdt, st->st_mode & 07777) < 0)
+ r = -errno;
+
+ ts[0] = st->st_atim;
+ ts[1] = st->st_mtim;
+ (void) futimens(fdt, ts);
+ (void) copy_xattr(fdf, fdt);
+
+ q = close(fdt);
+ fdt = -1;
+
+ if (q < 0) {
+ r = -errno;
+ (void) unlinkat(dt, to, 0);
+ }
+
+ (void) memorize_hardlink(hardlink_context, st, dt, to);
+ return r;
+}
+
+static int fd_copy_fifo(
+ int df,
+ const char *from,
+ const struct stat *st,
+ int dt,
+ const char *to,
+ uid_t override_uid,
+ gid_t override_gid,
+ CopyFlags copy_flags,
+ HardlinkContext *hardlink_context) {
+ int r;
+
+ assert(from);
+ assert(st);
+ assert(to);
+
+ r = try_hardlink(hardlink_context, st, dt, to);
+ if (r < 0)
+ return r;
+ if (r > 0) /* worked! */
+ return 0;
+
+ if (copy_flags & COPY_MAC_CREATE) {
+ r = mac_selinux_create_file_prepare_at(dt, to, S_IFIFO);
+ if (r < 0)
+ return r;
+ }
+ r = mkfifoat(dt, to, st->st_mode & 07777);
+ if (copy_flags & COPY_MAC_CREATE)
+ mac_selinux_create_file_clear();
+ if (r < 0)
+ return -errno;
+
+ if (fchownat(dt, to,
+ uid_is_valid(override_uid) ? override_uid : st->st_uid,
+ gid_is_valid(override_gid) ? override_gid : st->st_gid,
+ AT_SYMLINK_NOFOLLOW) < 0)
+ r = -errno;
+
+ if (fchmodat(dt, to, st->st_mode & 07777, 0) < 0)
+ r = -errno;
+
+ (void) memorize_hardlink(hardlink_context, st, dt, to);
+ return r;
+}
+
+static int fd_copy_node(
+ int df,
+ const char *from,
+ const struct stat *st,
+ int dt,
+ const char *to,
+ uid_t override_uid,
+ gid_t override_gid,
+ CopyFlags copy_flags,
+ HardlinkContext *hardlink_context) {
+ int r;
+
+ assert(from);
+ assert(st);
+ assert(to);
+
+ r = try_hardlink(hardlink_context, st, dt, to);
+ if (r < 0)
+ return r;
+ if (r > 0) /* worked! */
+ return 0;
+
+ if (copy_flags & COPY_MAC_CREATE) {
+ r = mac_selinux_create_file_prepare_at(dt, to, st->st_mode & S_IFMT);
+ if (r < 0)
+ return r;
+ }
+ r = mknodat(dt, to, st->st_mode, st->st_rdev);
+ if (copy_flags & COPY_MAC_CREATE)
+ mac_selinux_create_file_clear();
+ if (r < 0)
+ return -errno;
+
+ if (fchownat(dt, to,
+ uid_is_valid(override_uid) ? override_uid : st->st_uid,
+ gid_is_valid(override_gid) ? override_gid : st->st_gid,
+ AT_SYMLINK_NOFOLLOW) < 0)
+ r = -errno;
+
+ if (fchmodat(dt, to, st->st_mode & 07777, 0) < 0)
+ r = -errno;
+
+ (void) memorize_hardlink(hardlink_context, st, dt, to);
+ return r;
+}
+
+static int fd_copy_directory(
+ int df,
+ const char *from,
+ const struct stat *st,
+ int dt,
+ const char *to,
+ dev_t original_device,
+ unsigned depth_left,
+ uid_t override_uid,
+ gid_t override_gid,
+ CopyFlags copy_flags,
+ HardlinkContext *hardlink_context,
+ const char *display_path,
+ copy_progress_path_t progress_path,
+ copy_progress_bytes_t progress_bytes,
+ void *userdata) {
+
+ _cleanup_(hardlink_context_destroy) HardlinkContext our_hardlink_context = {
+ .dir_fd = -1,
+ .parent_fd = -1,
+ };
+
+ _cleanup_close_ int fdf = -1, fdt = -1;
+ _cleanup_closedir_ DIR *d = NULL;
+ struct dirent *de;
+ bool exists, created;
+ int r;
+
+ assert(st);
+ assert(to);
+
+ if (depth_left == 0)
+ return -ENAMETOOLONG;
+
+ if (from)
+ fdf = openat(df, from, O_RDONLY|O_DIRECTORY|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW);
+ else
+ fdf = fcntl(df, F_DUPFD_CLOEXEC, 3);
+ if (fdf < 0)
+ return -errno;
+
+ if (!hardlink_context) {
+ /* If recreating hardlinks is requested let's set up a context for that now. */
+ r = hardlink_context_setup(&our_hardlink_context, dt, to, copy_flags);
+ if (r < 0)
+ return r;
+ if (r > 0) /* It's enabled and allocated, let's now use the same context for all recursive
+ * invocations from here down */
+ hardlink_context = &our_hardlink_context;
+ }
+
+ d = take_fdopendir(&fdf);
+ if (!d)
+ return -errno;
+
+ exists = false;
+ if (copy_flags & COPY_MERGE_EMPTY) {
+ r = dir_is_empty_at(dt, to);
+ if (r < 0 && r != -ENOENT)
+ return r;
+ else if (r == 1)
+ exists = true;
+ }
+
+ if (exists)
+ created = false;
+ else {
+ if (copy_flags & COPY_MAC_CREATE)
+ r = mkdirat_label(dt, to, st->st_mode & 07777);
+ else
+ r = mkdirat(dt, to, st->st_mode & 07777);
+ if (r >= 0)
+ created = true;
+ else if (errno == EEXIST && (copy_flags & COPY_MERGE))
+ created = false;
+ else
+ return -errno;
+ }
+
+ fdt = openat(dt, to, O_RDONLY|O_DIRECTORY|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW);
+ if (fdt < 0)
+ return -errno;
+
+ r = 0;
+
+ FOREACH_DIRENT_ALL(de, d, return -errno) {
+ const char *child_display_path = NULL;
+ _cleanup_free_ char *dp = NULL;
+ struct stat buf;
+ int q;
+
+ if (dot_or_dot_dot(de->d_name))
+ continue;
+
+ if (FLAGS_SET(copy_flags, COPY_SIGINT)) {
+ r = sigint_pending();
+ if (r < 0)
+ return r;
+ if (r > 0)
+ return -EINTR;
+ }
+
+ if (fstatat(dirfd(d), de->d_name, &buf, AT_SYMLINK_NOFOLLOW) < 0) {
+ r = -errno;
+ continue;
+ }
+
+ if (progress_path) {
+ if (display_path)
+ child_display_path = dp = path_join(display_path, de->d_name);
+ else
+ child_display_path = de->d_name;
+
+ r = progress_path(child_display_path, &buf, userdata);
+ if (r < 0)
+ return r;
+ }
+
+ if (S_ISDIR(buf.st_mode)) {
+ /*
+ * Don't descend into directories on other file systems, if this is requested. We do a simple
+ * .st_dev check here, which basically comes for free. Note that we do this check only on
+ * directories, not other kind of file system objects, for two reason:
+ *
+ * • The kernel's overlayfs pseudo file system that overlays multiple real file systems
+ * propagates the .st_dev field of the file system a file originates from all the way up
+ * through the stack to stat(). It doesn't do that for directories however. This means that
+ * comparing .st_dev on non-directories suggests that they all are mount points. To avoid
+ * confusion we hence avoid relying on this check for regular files.
+ *
+ * • The main reason we do this check at all is to protect ourselves from bind mount cycles,
+ * where we really want to avoid descending down in all eternity. However the .st_dev check
+ * is usually not sufficient for this protection anyway, as bind mount cycles from the same
+ * file system onto itself can't be detected that way. (Note we also do a recursion depth
+ * check, which is probably the better protection in this regard, which is why
+ * COPY_SAME_MOUNT is optional).
+ */
+
+ if (FLAGS_SET(copy_flags, COPY_SAME_MOUNT)) {
+ if (buf.st_dev != original_device)
+ continue;
+
+ r = fd_is_mount_point(dirfd(d), de->d_name, 0);
+ if (r < 0)
+ return r;
+ if (r > 0)
+ continue;
+ }
+
+ q = fd_copy_directory(dirfd(d), de->d_name, &buf, fdt, de->d_name, original_device, depth_left-1, override_uid, override_gid, copy_flags, hardlink_context, child_display_path, progress_path, progress_bytes, userdata);
+ } else if (S_ISREG(buf.st_mode))
+ q = fd_copy_regular(dirfd(d), de->d_name, &buf, fdt, de->d_name, override_uid, override_gid, copy_flags, hardlink_context, progress_bytes, userdata);
+ else if (S_ISLNK(buf.st_mode))
+ q = fd_copy_symlink(dirfd(d), de->d_name, &buf, fdt, de->d_name, override_uid, override_gid, copy_flags);
+ else if (S_ISFIFO(buf.st_mode))
+ q = fd_copy_fifo(dirfd(d), de->d_name, &buf, fdt, de->d_name, override_uid, override_gid, copy_flags, hardlink_context);
+ else if (S_ISBLK(buf.st_mode) || S_ISCHR(buf.st_mode) || S_ISSOCK(buf.st_mode))
+ q = fd_copy_node(dirfd(d), de->d_name, &buf, fdt, de->d_name, override_uid, override_gid, copy_flags, hardlink_context);
+ else
+ q = -EOPNOTSUPP;
+
+ if (q == -EINTR) /* Propagate SIGINT up instantly */
+ return q;
+ if (q == -EEXIST && (copy_flags & COPY_MERGE))
+ q = 0;
+ if (q < 0)
+ r = q;
+ }
+
+ if (created) {
+ struct timespec ut[2] = {
+ st->st_atim,
+ st->st_mtim
+ };
+
+ if (fchown(fdt,
+ uid_is_valid(override_uid) ? override_uid : st->st_uid,
+ gid_is_valid(override_gid) ? override_gid : st->st_gid) < 0)
+ r = -errno;
+
+ if (fchmod(fdt, st->st_mode & 07777) < 0)
+ r = -errno;
+
+ (void) copy_xattr(dirfd(d), fdt);
+ (void) futimens(fdt, ut);
+ }
+
+ return r;
+}
+
+int copy_tree_at_full(
+ int fdf,
+ const char *from,
+ int fdt,
+ const char *to,
+ uid_t override_uid,
+ gid_t override_gid,
+ CopyFlags copy_flags,
+ copy_progress_path_t progress_path,
+ copy_progress_bytes_t progress_bytes,
+ void *userdata) {
+
+ struct stat st;
+
+ assert(from);
+ assert(to);
+
+ if (fstatat(fdf, from, &st, AT_SYMLINK_NOFOLLOW) < 0)
+ return -errno;
+
+ if (S_ISREG(st.st_mode))
+ return fd_copy_regular(fdf, from, &st, fdt, to, override_uid, override_gid, copy_flags, NULL, progress_bytes, userdata);
+ else if (S_ISDIR(st.st_mode))
+ return fd_copy_directory(fdf, from, &st, fdt, to, st.st_dev, COPY_DEPTH_MAX, override_uid, override_gid, copy_flags, NULL, NULL, progress_path, progress_bytes, userdata);
+ else if (S_ISLNK(st.st_mode))
+ return fd_copy_symlink(fdf, from, &st, fdt, to, override_uid, override_gid, copy_flags);
+ else if (S_ISFIFO(st.st_mode))
+ return fd_copy_fifo(fdf, from, &st, fdt, to, override_uid, override_gid, copy_flags, NULL);
+ else if (S_ISBLK(st.st_mode) || S_ISCHR(st.st_mode) || S_ISSOCK(st.st_mode))
+ return fd_copy_node(fdf, from, &st, fdt, to, override_uid, override_gid, copy_flags, NULL);
+ else
+ return -EOPNOTSUPP;
+}
+
+int copy_directory_fd_full(
+ int dirfd,
+ const char *to,
+ CopyFlags copy_flags,
+ copy_progress_path_t progress_path,
+ copy_progress_bytes_t progress_bytes,
+ void *userdata) {
+
+ struct stat st;
+
+ assert(dirfd >= 0);
+ assert(to);
+
+ if (fstat(dirfd, &st) < 0)
+ return -errno;
+
+ if (!S_ISDIR(st.st_mode))
+ return -ENOTDIR;
+
+ return fd_copy_directory(dirfd, NULL, &st, AT_FDCWD, to, st.st_dev, COPY_DEPTH_MAX, UID_INVALID, GID_INVALID, copy_flags, NULL, NULL, progress_path, progress_bytes, userdata);
+}
+
+int copy_directory_full(
+ const char *from,
+ const char *to,
+ CopyFlags copy_flags,
+ copy_progress_path_t progress_path,
+ copy_progress_bytes_t progress_bytes,
+ void *userdata) {
+
+ struct stat st;
+
+ assert(from);
+ assert(to);
+
+ if (lstat(from, &st) < 0)
+ return -errno;
+
+ if (!S_ISDIR(st.st_mode))
+ return -ENOTDIR;
+
+ return fd_copy_directory(AT_FDCWD, from, &st, AT_FDCWD, to, st.st_dev, COPY_DEPTH_MAX, UID_INVALID, GID_INVALID, copy_flags, NULL, NULL, progress_path, progress_bytes, userdata);
+}
+
+int copy_file_fd_full(
+ const char *from,
+ int fdt,
+ CopyFlags copy_flags,
+ copy_progress_bytes_t progress_bytes,
+ void *userdata) {
+
+ _cleanup_close_ int fdf = -1;
+ int r;
+
+ assert(from);
+ assert(fdt >= 0);
+
+ fdf = open(from, O_RDONLY|O_CLOEXEC|O_NOCTTY);
+ if (fdf < 0)
+ return -errno;
+
+ r = copy_bytes_full(fdf, fdt, (uint64_t) -1, copy_flags, NULL, NULL, progress_bytes, userdata);
+
+ (void) copy_times(fdf, fdt, copy_flags);
+ (void) copy_xattr(fdf, fdt);
+
+ return r;
+}
+
+int copy_file_full(
+ const char *from,
+ const char *to,
+ int flags,
+ mode_t mode,
+ unsigned chattr_flags,
+ unsigned chattr_mask,
+ CopyFlags copy_flags,
+ copy_progress_bytes_t progress_bytes,
+ void *userdata) {
+
+ int fdt = -1, r;
+
+ assert(from);
+ assert(to);
+
+ RUN_WITH_UMASK(0000) {
+ if (copy_flags & COPY_MAC_CREATE) {
+ r = mac_selinux_create_file_prepare(to, S_IFREG);
+ if (r < 0)
+ return r;
+ }
+ fdt = open(to, flags|O_WRONLY|O_CREAT|O_CLOEXEC|O_NOCTTY, mode);
+ if (copy_flags & COPY_MAC_CREATE)
+ mac_selinux_create_file_clear();
+ if (fdt < 0)
+ return -errno;
+ }
+
+ if (chattr_mask != 0)
+ (void) chattr_fd(fdt, chattr_flags, chattr_mask & CHATTR_EARLY_FL, NULL);
+
+ r = copy_file_fd_full(from, fdt, copy_flags, progress_bytes, userdata);
+ if (r < 0) {
+ close(fdt);
+ (void) unlink(to);
+ return r;
+ }
+
+ if (chattr_mask != 0)
+ (void) chattr_fd(fdt, chattr_flags, chattr_mask & ~CHATTR_EARLY_FL, NULL);
+
+ if (close(fdt) < 0) {
+ unlink_noerrno(to);
+ return -errno;
+ }
+
+ return 0;
+}
+
+int copy_file_atomic_full(
+ const char *from,
+ const char *to,
+ mode_t mode,
+ unsigned chattr_flags,
+ unsigned chattr_mask,
+ CopyFlags copy_flags,
+ copy_progress_bytes_t progress_bytes,
+ void *userdata) {
+
+ _cleanup_(unlink_and_freep) char *t = NULL;
+ _cleanup_close_ int fdt = -1;
+ int r;
+
+ assert(from);
+ assert(to);
+
+ /* We try to use O_TMPFILE here to create the file if we can. Note that this only works if COPY_REPLACE is not
+ * set though as we need to use linkat() for linking the O_TMPFILE file into the file system but that system
+ * call can't replace existing files. Hence, if COPY_REPLACE is set we create a temporary name in the file
+ * system right-away and unconditionally which we then can renameat() to the right name after we completed
+ * writing it. */
+
+ if (copy_flags & COPY_REPLACE) {
+ r = tempfn_random(to, NULL, &t);
+ if (r < 0)
+ return r;
+
+ if (copy_flags & COPY_MAC_CREATE) {
+ r = mac_selinux_create_file_prepare(to, S_IFREG);
+ if (r < 0) {
+ t = mfree(t);
+ return r;
+ }
+ }
+ fdt = open(t, O_CREAT|O_EXCL|O_NOFOLLOW|O_NOCTTY|O_WRONLY|O_CLOEXEC, 0600);
+ if (copy_flags & COPY_MAC_CREATE)
+ mac_selinux_create_file_clear();
+ if (fdt < 0) {
+ t = mfree(t);
+ return -errno;
+ }
+ } else {
+ if (copy_flags & COPY_MAC_CREATE) {
+ r = mac_selinux_create_file_prepare(to, S_IFREG);
+ if (r < 0)
+ return r;
+ }
+ fdt = open_tmpfile_linkable(to, O_WRONLY|O_CLOEXEC, &t);
+ if (copy_flags & COPY_MAC_CREATE)
+ mac_selinux_create_file_clear();
+ if (fdt < 0)
+ return fdt;
+ }
+
+ if (chattr_mask != 0)
+ (void) chattr_fd(fdt, chattr_flags, chattr_mask & CHATTR_EARLY_FL, NULL);
+
+ r = copy_file_fd_full(from, fdt, copy_flags, progress_bytes, userdata);
+ if (r < 0)
+ return r;
+
+ if (fchmod(fdt, mode) < 0)
+ return -errno;
+
+ if (copy_flags & COPY_REPLACE) {
+ if (renameat(AT_FDCWD, t, AT_FDCWD, to) < 0)
+ return -errno;
+ } else {
+ r = link_tmpfile(fdt, t, to);
+ if (r < 0)
+ return r;
+ }
+
+ if (chattr_mask != 0)
+ (void) chattr_fd(fdt, chattr_flags, chattr_mask & ~CHATTR_EARLY_FL, NULL);
+
+ t = mfree(t);
+ return 0;
+}
+
+int copy_times(int fdf, int fdt, CopyFlags flags) {
+ struct timespec ut[2];
+ struct stat st;
+
+ assert(fdf >= 0);
+ assert(fdt >= 0);
+
+ if (fstat(fdf, &st) < 0)
+ return -errno;
+
+ ut[0] = st.st_atim;
+ ut[1] = st.st_mtim;
+
+ if (futimens(fdt, ut) < 0)
+ return -errno;
+
+ if (FLAGS_SET(flags, COPY_CRTIME)) {
+ usec_t crtime;
+
+ if (fd_getcrtime(fdf, &crtime) >= 0)
+ (void) fd_setcrtime(fdt, crtime);
+ }
+
+ return 0;
+}
+
+int copy_access(int fdf, int fdt) {
+ struct stat st;
+
+ assert(fdf >= 0);
+ assert(fdt >= 0);
+
+ if (fstat(fdf, &st) < 0)
+ return -errno;
+
+ if (fchmod(fdt, st.st_mode & 07777) < 0)
+ return -errno;
+
+ return 0;
+}
+
+int copy_xattr(int fdf, int fdt) {
+ _cleanup_free_ char *names = NULL;
+ int ret = 0, r;
+ const char *p;
+
+ r = flistxattr_malloc(fdf, &names);
+ if (r < 0)
+ return r;
+
+ NULSTR_FOREACH(p, names) {
+ _cleanup_free_ char *value = NULL;
+
+ if (!startswith(p, "user."))
+ continue;
+
+ r = fgetxattr_malloc(fdf, p, &value);
+ if (r == -ENODATA)
+ continue; /* gone by now */
+ if (r < 0)
+ return r;
+
+ if (fsetxattr(fdt, p, value, r, 0) < 0)
+ ret = -errno;
+ }
+
+ return ret;
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-30 05:36:04 +0000