copy.c revision 97b11eedff9d2e17101ad453caf9e48b73246719
/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
/***
This file is part of systemd.
Copyright 2014 Lennart Poettering
systemd is free software; you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
systemd is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/
#include <sys/sendfile.h>
#include <sys/xattr.h>
#include "util.h"
#include "btrfs-util.h"
#include "strv.h"
#include "copy.h"
#define COPY_BUFFER_SIZE (16*1024)
int copy_bytes(int fdf, int fdt, off_t max_bytes, bool try_reflink) {
bool try_sendfile = true;
int r;
assert(fdf >= 0);
assert(fdt >= 0);
/* Try btrfs reflinks first. */
if (try_reflink && max_bytes == (off_t) -1) {
r = btrfs_reflink(fdf, fdt);
if (r >= 0)
return r;
}
for (;;) {
size_t m = COPY_BUFFER_SIZE;
ssize_t n;
if (max_bytes != (off_t) -1) {
if (max_bytes <= 0)
return -EFBIG;
if ((off_t) m > max_bytes)
m = (size_t) max_bytes;
}
/* First try sendfile(), unless we already tried */
if (try_sendfile) {
n = sendfile(fdt, fdf, NULL, m);
if (n < 0) {
if (errno != EINVAL && errno != ENOSYS)
return -errno;
try_sendfile = false;
/* use fallback below */
} else if (n == 0) /* EOF */
break;
else if (n > 0)
/* Succcess! */
goto next;
}
/* As a fallback just copy bits by hand */
{
char buf[m];
n = read(fdf, buf, m);
if (n < 0)
return -errno;
if (n == 0) /* EOF */
break;
r = loop_write(fdt, buf, (size_t) n, false);
if (r < 0)
return r;
}
next:
if (max_bytes != (off_t) -1) {
assert(max_bytes >= n);
max_bytes -= n;
}
}
return 0;
}
static int fd_copy_symlink(int df, const char *from, const struct stat *st, int dt, const char *to) {
_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 (symlinkat(target, dt, to) < 0)
return -errno;
if (fchownat(dt, to, st->st_uid, st->st_gid, AT_SYMLINK_NOFOLLOW) < 0)
return -errno;
return 0;
}
static int fd_copy_regular(int df, const char *from, const struct stat *st, int dt, const char *to) {
_cleanup_close_ int fdf = -1, fdt = -1;
struct timespec ts[2];
int r, q;
assert(from);
assert(st);
assert(to);
fdf = openat(df, from, O_RDONLY|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW);
if (fdf < 0)
return -errno;
fdt = openat(dt, to, O_WRONLY|O_CREAT|O_EXCL|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW, st->st_mode & 07777);
if (fdt < 0)
return -errno;
r = copy_bytes(fdf, fdt, (off_t) -1, true);
if (r < 0) {
unlinkat(dt, to, 0);
return r;
}
if (fchown(fdt, st->st_uid, 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;
unlinkat(dt, to, 0);
}
return r;
}
static int fd_copy_fifo(int df, const char *from, const struct stat *st, int dt, const char *to) {
int r;
assert(from);
assert(st);
assert(to);
r = mkfifoat(dt, to, st->st_mode & 07777);
if (r < 0)
return -errno;
if (fchownat(dt, to, st->st_uid, st->st_gid, AT_SYMLINK_NOFOLLOW) < 0)
r = -errno;
if (fchmodat(dt, to, st->st_mode & 07777, 0) < 0)
r = -errno;
return r;
}
static int fd_copy_node(int df, const char *from, const struct stat *st, int dt, const char *to) {
int r;
assert(from);
assert(st);
assert(to);
r = mknodat(dt, to, st->st_mode, st->st_rdev);
if (r < 0)
return -errno;
if (fchownat(dt, to, st->st_uid, st->st_gid, AT_SYMLINK_NOFOLLOW) < 0)
r = -errno;
if (fchmodat(dt, to, st->st_mode & 07777, 0) < 0)
r = -errno;
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,
bool merge) {
_cleanup_close_ int fdf = -1, fdt = -1;
_cleanup_closedir_ DIR *d = NULL;
struct dirent *de;
bool created;
int r;
assert(st);
assert(to);
if (from)
fdf = openat(df, from, O_RDONLY|O_DIRECTORY|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW);
else
fdf = fcntl(df, F_DUPFD_CLOEXEC, 3);
d = fdopendir(fdf);
if (!d)
return -errno;
fdf = -1;
r = mkdirat(dt, to, st->st_mode & 07777);
if (r >= 0)
created = true;
else if (errno == EEXIST && 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;
if (created) {
struct timespec ut[2] = {
st->st_atim,
st->st_mtim
};
if (fchown(fdt, st->st_uid, st->st_gid) < 0)
r = -errno;
if (fchmod(fdt, st->st_mode & 07777) < 0)
r = -errno;
(void) futimens(fdt, ut);
(void) copy_xattr(dirfd(d), fdt);
}
FOREACH_DIRENT_ALL(de, d, return -errno) {
struct stat buf;
int q;
if (STR_IN_SET(de->d_name, ".", ".."))
continue;
if (fstatat(dirfd(d), de->d_name, &buf, AT_SYMLINK_NOFOLLOW) < 0) {
r = -errno;
continue;
}
if (buf.st_dev != original_device)
continue;
if (S_ISREG(buf.st_mode))
q = fd_copy_regular(dirfd(d), de->d_name, &buf, fdt, de->d_name);
else if (S_ISDIR(buf.st_mode))
q = fd_copy_directory(dirfd(d), de->d_name, &buf, fdt, de->d_name, original_device, merge);
else if (S_ISLNK(buf.st_mode))
q = fd_copy_symlink(dirfd(d), de->d_name, &buf, fdt, de->d_name);
else if (S_ISFIFO(buf.st_mode))
q = fd_copy_fifo(dirfd(d), de->d_name, &buf, fdt, de->d_name);
else if (S_ISBLK(buf.st_mode) || S_ISCHR(buf.st_mode))
q = fd_copy_node(dirfd(d), de->d_name, &buf, fdt, de->d_name);
else
q = -EOPNOTSUPP;
if (q == -EEXIST && merge)
q = 0;
if (q < 0)
r = q;
}
return r;
}
int copy_tree_at(int fdf, const char *from, int fdt, const char *to, bool merge) {
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);
else if (S_ISDIR(st.st_mode))
return fd_copy_directory(fdf, from, &st, fdt, to, st.st_dev, merge);
else if (S_ISLNK(st.st_mode))
return fd_copy_symlink(fdf, from, &st, fdt, to);
else if (S_ISFIFO(st.st_mode))
return fd_copy_fifo(fdf, from, &st, fdt, to);
else if (S_ISBLK(st.st_mode) || S_ISCHR(st.st_mode))
return fd_copy_node(fdf, from, &st, fdt, to);
else
return -EOPNOTSUPP;
}
int copy_tree(const char *from, const char *to, bool merge) {
return copy_tree_at(AT_FDCWD, from, AT_FDCWD, to, merge);
}
int copy_directory_fd(int dirfd, const char *to, bool merge) {
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, merge);
}
int copy_file_fd(const char *from, int fdt, bool try_reflink) {
_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(fdf, fdt, (off_t) -1, try_reflink);
(void) copy_times(fdf, fdt);
(void) copy_xattr(fdf, fdt);
return r;
}
int copy_file(const char *from, const char *to, int flags, mode_t mode, unsigned chattr_flags) {
int fdt = -1, r;
assert(from);
assert(to);
RUN_WITH_UMASK(0000) {
fdt = open(to, flags|O_WRONLY|O_CREAT|O_CLOEXEC|O_NOCTTY, mode);
if (fdt < 0)
return -errno;
}
if (chattr_flags != 0)
(void) chattr_fd(fdt, chattr_flags, (unsigned) -1);
r = copy_file_fd(from, fdt, true);
if (r < 0) {
close(fdt);
unlink(to);
return r;
}
if (close(fdt) < 0) {
unlink_noerrno(to);
return -errno;
}
return 0;
}
int copy_file_atomic(const char *from, const char *to, mode_t mode, bool replace, unsigned chattr_flags) {
_cleanup_free_ char *t = NULL;
int r;
assert(from);
assert(to);
r = tempfn_random(to, NULL, &t);
if (r < 0)
return r;
r = copy_file(from, t, O_NOFOLLOW|O_EXCL, mode, chattr_flags);
if (r < 0)
return r;
if (replace) {
r = renameat(AT_FDCWD, t, AT_FDCWD, to);
if (r < 0)
r = -errno;
} else
r = rename_noreplace(AT_FDCWD, t, AT_FDCWD, to);
if (r < 0) {
(void) unlink_noerrno(t);
return r;
}
return 0;
}
int copy_times(int fdf, int fdt) {
struct timespec ut[2];
struct stat st;
usec_t crtime = 0;
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 (fd_getcrtime(fdf, &crtime) >= 0)
(void) fd_setcrtime(fdt, crtime);
return 0;
}
int copy_xattr(int fdf, int fdt) {
_cleanup_free_ char *bufa = NULL, *bufb = NULL;
size_t sza = 100, szb = 100;
ssize_t n;
int ret = 0;
const char *p;
for (;;) {
bufa = malloc(sza);
if (!bufa)
return -ENOMEM;
n = flistxattr(fdf, bufa, sza);
if (n == 0)
return 0;
if (n > 0)
break;
if (errno != ERANGE)
return -errno;
sza *= 2;
bufa = mfree(bufa);
}
p = bufa;
while (n > 0) {
size_t l;
l = strlen(p);
assert(l < (size_t) n);
if (startswith(p, "user.")) {
ssize_t m;
if (!bufb) {
bufb = malloc(szb);
if (!bufb)
return -ENOMEM;
}
m = fgetxattr(fdf, p, bufb, szb);
if (m < 0) {
if (errno == ERANGE) {
szb *= 2;
bufb = mfree(bufb);
continue;
}
return -errno;
}
if (fsetxattr(fdt, p, bufb, m, 0) < 0)
ret = -errno;
}
p += l + 1;
n -= l + 1;
}
return ret;
}