add --overwrite option to ignore file conflicts

Allows for safer, more fine-grained control for overwriting files than
--force's all-or-nothing approach.

Implements FS#31549.

Signed-off-by: Andrew Gregory <andrew.gregory.8@gmail.com>
Signed-off-by: Allan McRae <allan@archlinux.org>

4 files changed, 37 insertions, 4 deletions

diff --git a/lib/libalpm/alpm.h b/lib/libalpm/alpm.h
index 448d42d2..2637a055 100644
--- a/lib/libalpm/alpm.h
+++ b/lib/libalpm/alpm.h
@@ -830,6 +830,11 @@ int alpm_option_add_hookdir(alpm_handle_t *handle, const char *hookdir);
 int alpm_option_remove_hookdir(alpm_handle_t *handle, const char *hookdir);
 /** @} */
 
+alpm_list_t *alpm_option_get_overwrite_files(alpm_handle_t *handle);
+int alpm_option_set_overwrite_files(alpm_handle_t *handle, alpm_list_t *globs);
+int alpm_option_add_overwrite_file(alpm_handle_t *handle, const char *glob);
+int alpm_option_remove_overwrite_file(alpm_handle_t *handle, const char *glob);
+
 /** Returns the logfile name. */
 const char *alpm_option_get_logfile(alpm_handle_t *handle);
 /** Sets the logfile name. */
diff --git a/lib/libalpm/conflict.c b/lib/libalpm/conflict.c
index b1666dfe..0e37419f 100644
--- a/lib/libalpm/conflict.c
+++ b/lib/libalpm/conflict.c
@@ -385,6 +385,12 @@ static alpm_list_t *alpm_db_find_file_owners(alpm_db_t* db, const char *path)
 	return owners;
 }
 
+static int _alpm_can_overwrite_file(alpm_handle_t *handle, const char *path)
+{
+	return handle->trans->flags & ALPM_TRANS_FLAG_FORCE
+		|| _alpm_fnmatch_patterns(handle->overwrite_files, path) == 0;
+}
+
 /**
  * @brief Find file conflicts that may occur during the transaction.
  *
@@ -448,8 +454,8 @@ alpm_list_t *_alpm_db_find_fileconflicts(alpm_handle_t *handle,
 					/* can skip file-file conflicts when forced *
 					 * checking presence in p2_files detects dir-file or file-dir
 					 * conflicts as the path from p1 is returned */
-					if((handle->trans->flags & ALPM_TRANS_FLAG_FORCE) &&
-							alpm_filelist_contains(p2_files, filename)) {
+					if(_alpm_can_overwrite_file(handle, filename)
+							&& alpm_filelist_contains(p2_files, filename)) {
 						_alpm_log(handle, ALPM_LOG_DEBUG,
 							"%s exists in both '%s' and '%s'\n", filename,
 							p1->name, p2->name);
@@ -654,8 +660,8 @@ alpm_list_t *_alpm_db_find_fileconflicts(alpm_handle_t *handle,
 			}
 
 			/* skip file-file conflicts when being forced */
-			if((handle->trans->flags & ALPM_TRANS_FLAG_FORCE) &&
-					!S_ISDIR(lsbuf.st_mode)) {
+			if(!S_ISDIR(lsbuf.st_mode)
+					&& _alpm_can_overwrite_file(handle, filestr)) {
 				_alpm_log(handle, ALPM_LOG_DEBUG,
 							"conflict with file on filesystem being forced\n");
 				resolved_conflict = 1;
diff --git a/lib/libalpm/handle.c b/lib/libalpm/handle.c
index f08f614c..b6b27881 100644
--- a/lib/libalpm/handle.c
+++ b/lib/libalpm/handle.c
@@ -283,6 +283,12 @@ alpm_list_t SYMEXPORT *alpm_option_get_ignoregroups(alpm_handle_t *handle)
 	return handle->ignoregroup;
 }
 
+alpm_list_t SYMEXPORT *alpm_option_get_overwrite_files(alpm_handle_t *handle)
+{
+	CHECK_HANDLE(handle, return NULL);
+	return handle->overwrite_files;
+}
+
 alpm_list_t SYMEXPORT *alpm_option_get_assumeinstalled(alpm_handle_t *handle)
 {
 	CHECK_HANDLE(handle, return NULL);
@@ -657,6 +663,21 @@ int SYMEXPORT alpm_option_remove_ignoregroup(alpm_handle_t *handle, const char *
 	return _alpm_option_strlist_rem(handle, &(handle->ignoregroup), grp);
 }
 
+int SYMEXPORT alpm_option_add_overwrite_file(alpm_handle_t *handle, const char *glob)
+{
+	return _alpm_option_strlist_add(handle, &(handle->overwrite_files), glob);
+}
+
+int SYMEXPORT alpm_option_set_overwrite_files(alpm_handle_t *handle, alpm_list_t *globs)
+{
+	return _alpm_option_strlist_set(handle, &(handle->overwrite_files), globs);
+}
+
+int SYMEXPORT alpm_option_remove_overwrite_file(alpm_handle_t *handle, const char *glob)
+{
+	return _alpm_option_strlist_rem(handle, &(handle->overwrite_files), glob);
+}
+
 int SYMEXPORT alpm_option_add_assumeinstalled(alpm_handle_t *handle, const alpm_depend_t *dep)
 {
 	alpm_depend_t *depcpy;
diff --git a/lib/libalpm/handle.h b/lib/libalpm/handle.h
index 223eac12..115c3481 100644
--- a/lib/libalpm/handle.h
+++ b/lib/libalpm/handle.h
@@ -84,6 +84,7 @@ struct __alpm_handle_t {
 	char *gpgdir;            /* Directory where GnuPG files are stored */
 	alpm_list_t *cachedirs;  /* Paths to pacman cache directories */
 	alpm_list_t *hookdirs;   /* Paths to hook directories */
+	alpm_list_t *overwrite_files; /* Paths that may be overwritten */
 
 	/* package lists */
 	alpm_list_t *noupgrade;   /* List of packages NOT to be upgraded */