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authorFlorian Weimer <fweimer@redhat.com>2020-11-26 16:59:44 +0100
committerFlorian Weimer <fweimer@redhat.com>2020-11-26 18:19:46 +0100
commit603ae243f6fe03208a3bb92adecf72403367bd95 (patch)
tree7d839778df93a22f37884830f95d58927f6ed774
parent05d38b3ef505af2fbe8df0d07f4158fc0e96a7a5 (diff)
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support: Add support_copy_file
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
-rw-r--r--support/Makefile1
-rw-r--r--support/support.h5
-rw-r--r--support/support_copy_file.c43
3 files changed, 49 insertions, 0 deletions
diff --git a/support/Makefile b/support/Makefile
index 4154863..f5f59bf 100644
--- a/support/Makefile
+++ b/support/Makefile
@@ -46,6 +46,7 @@ libsupport-routines = \
support_capture_subprocess \
support_capture_subprocess_check \
support_chroot \
+ support_copy_file \
support_copy_file_range \
support_descriptor_supports_holes \
support_descriptors \
diff --git a/support/support.h b/support/support.h
index 905b5a7..abda3a6 100644
--- a/support/support.h
+++ b/support/support.h
@@ -119,6 +119,11 @@ extern const char support_install_rootsbindir[];
/* Corresponds to the install's compiled locale directory. */
extern const char support_complocaledir_prefix[];
+/* Copies the file at the path FROM to TO. If TO does not exist, it
+ is created. If TO is a regular file, it is truncated before
+ copying. The file mode is copied, but the permissions are not. */
+extern void support_copy_file (const char *from, const char *to);
+
extern ssize_t support_copy_file_range (int, off64_t *, int, off64_t *,
size_t, unsigned int);
diff --git a/support/support_copy_file.c b/support/support_copy_file.c
new file mode 100644
index 0000000..c93e1e5
--- /dev/null
+++ b/support/support_copy_file.c
@@ -0,0 +1,43 @@
+/* Copy a file from one path to another.
+ Copyright (C) 2020 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library 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.
+
+ The GNU C Library 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 the GNU C Library; if not, see
+ <https://www.gnu.org/licenses/>. */
+
+#include <fcntl.h>
+#include <support/check.h>
+#include <support/support.h>
+#include <support/xunistd.h>
+
+void
+support_copy_file (const char *from, const char *to)
+{
+ struct stat64 st;
+ xstat (from, &st);
+ int fd_from = xopen (from, O_RDONLY, 0);
+ mode_t mode = st.st_mode & 0777;
+ int fd_to = xopen (to, O_WRONLY | O_TRUNC | O_CREAT, mode);
+ ssize_t ret = support_copy_file_range (fd_from, NULL, fd_to, NULL,
+ st.st_size, 0);
+ if (ret < 0)
+ FAIL_EXIT1 ("copying from \"%s\" to \"%s\": %m", from, to);
+ if (ret != st.st_size)
+ FAIL_EXIT1 ("copying from \"%s\" to \"%s\": only %zd of %llu bytes copied",
+ from, to, ret, (unsigned long long int) st.st_size);
+ if (fchmod (fd_to, mode) < 0)
+ FAIL_EXIT1 ("fchmod on %s to 0%o: %m", to, mode);
+ xclose (fd_to);
+ xclose (fd_from);
+}