diff options
| -rw-r--r-- | support/Makefile | 1 | ||||
| -rw-r--r-- | support/support.h | 5 | ||||
| -rw-r--r-- | support/support_copy_file.c | 43 |
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); +} |