Prep v226: Add src/basic/copy.[hc] to libbasic, the function copy_bytes() is needed by pager.c

2 files changed, 563 insertions, 0 deletions

diff --git a/src/basic/copy.c b/src/basic/copy.c
new file mode 100644
index 000000000..163bbf7c7
--- /dev/null
+++ b/src/basic/copy.c
@@ -0,0 +1,528 @@
+/*-*- 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, try_splice = true;
+        int r;
+
+        assert(fdf >= 0);
+        assert(fdt >= 0);
+#if 0
+        /* Try btrfs reflinks first. */
+        if (try_reflink && max_bytes == (off_t) -1) {
+                r = btrfs_reflink(fdf, fdt);
+                if (r >= 0)
+                        return r;
+        }
+#endif // 0
+        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)
+                                /* Success! */
+                                goto next;
+                }
+
+                /* The try splice, unless we already tried */
+                if (try_splice) {
+                        n  = splice(fdf, NULL, fdt, NULL, m, 0);
+                        if (n < 0) {
+                                if (errno != EINVAL && errno != ENOSYS)
+                                        return -errno;
+
+                                try_splice = false;
+                                /* use fallback below */
+                        } else if (n == 0) /* EOF */
+                                break;
+                        else if (n > 0)
+                                /* Success! */
+                                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;
+}
+
+// UNNEEDED by elogind
+#if 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;
+}
+#endif // 0
diff --git a/src/basic/copy.h b/src/basic/copy.h
new file mode 100644
index 000000000..1909de4b8
--- /dev/null
+++ b/src/basic/copy.h
@@ -0,0 +1,35 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+#pragma once
+
+/***
+  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 <stdbool.h>
+#include <sys/types.h>
+
+// UNNEEDED int copy_file_fd(const char *from, int to, bool try_reflink);
+// UNNEEDED int copy_file(const char *from, const char *to, int flags, mode_t mode, unsigned chattr_flags);
+// UNNEEDED int copy_file_atomic(const char *from, const char *to, mode_t mode, bool replace, unsigned chattr_flags);
+// UNNEEDED int copy_tree(const char *from, const char *to, bool merge);
+// UNNEEDED int copy_tree_at(int fdf, const char *from, int fdt, const char *to, bool merge);
+// UNNEEDED int copy_directory_fd(int dirfd, const char *to, bool merge);
+int copy_bytes(int fdf, int fdt, off_t max_bytes, bool try_reflink);
+// UNNEEDED int copy_times(int fdf, int fdt);
+// UNNEEDED int copy_xattr(int fdf, int fdt);