Add helper method for creating and opening archive object

This moves the common setup code of about 5 different callers into one
method. Error messages will now be common and shared in all places;
several paths did not have any messages at all before.

In addition, we now pick an ideal block size for the archive read based
off the larger value of our default buffer size or the st.st_blksize
field. For a filesystem such as NFS, this is often much larger than the
default 8192- values such as 32768 and 131072 are common.

Signed-off-by: Dan McGee <dan@archlinux.org>

1 files changed, 73 insertions, 22 deletions

diff --git a/lib/libalpm/util.c b/lib/libalpm/util.c
index 5070cb93..f5b79688 100644
--- a/lib/libalpm/util.c
+++ b/lib/libalpm/util.c
@@ -233,6 +233,64 @@ size_t _alpm_strip_newline(char *str)
 /* Compression functions */
 
 /**
+ * Open an archive for reading and perform the necessary boilerplate.
+ * This takes care of creating the libarchive 'archive' struct, setting up
+ * compression and format options, opening a file descriptor, setting up the
+ * buffer size, and performing a stat on the path once opened.
+ * @param handle the context handle
+ * @param path the path of the archive to open
+ * @param buf space for a stat buffer for the given path
+ * @param archive pointer to place the created archive object
+ * @param error error code to set on failure to open archive
+ * @return -1 on failure, >=0 file descriptor on success
+ */
+int _alpm_open_archive(alpm_handle_t *handle, const char *path,
+		struct stat *buf, struct archive **archive, alpm_errno_t error)
+{
+	int fd;
+	size_t bufsize = ALPM_BUFFER_SIZE;
+
+	if((*archive = archive_read_new()) == NULL) {
+		RET_ERR(handle, ALPM_ERR_LIBARCHIVE, -1);
+	}
+
+	archive_read_support_compression_all(*archive);
+	archive_read_support_format_all(*archive);
+
+	_alpm_log(handle, ALPM_LOG_DEBUG, "opening archive %s\n", path);
+	OPEN(fd, path, O_RDONLY);
+	if(fd < 0) {
+		_alpm_log(handle, ALPM_LOG_ERROR,
+				_("could not open file %s: %s\n"), path, strerror(errno));
+		archive_read_finish(*archive);
+		RET_ERR(handle, error, -1);
+	}
+
+	if(fstat(fd, buf) != 0) {
+		_alpm_log(handle, ALPM_LOG_ERROR,
+				_("could not stat file %s: %s\n"), path, strerror(errno));
+		archive_read_finish(*archive);
+		CLOSE(fd);
+		RET_ERR(handle, error, -1);
+	}
+#ifdef HAVE_STRUCT_STAT_ST_BLKSIZE
+	if(buf->st_blksize > ALPM_BUFFER_SIZE) {
+		bufsize = buf->st_blksize;
+	}
+#endif
+
+	if(archive_read_open_fd(*archive, fd, bufsize) != ARCHIVE_OK) {
+		_alpm_log(handle, ALPM_LOG_ERROR, _("could not open file %s: %s\n"),
+				path, archive_error_string(*archive));
+		archive_read_finish(*archive);
+		CLOSE(fd);
+		RET_ERR(handle, error, -1);
+	}
+
+	return fd;
+}
+
+/**
  * @brief Unpack a specific file in an archive.
  *
  * @param handle the context handle
@@ -259,34 +317,26 @@ int _alpm_unpack_single(alpm_handle_t *handle, const char *archive,
  * @brief Unpack a list of files in an archive.
  *
  * @param handle the context handle
- * @param archive the archive to unpack
+ * @param path the archive to unpack
  * @param prefix where to extract the files
  * @param list a list of files within the archive to unpack or NULL for all
  * @param breakfirst break after the first entry found
  *
  * @return 0 on success, 1 on failure
  */
-int _alpm_unpack(alpm_handle_t *handle, const char *archive, const char *prefix,
+int _alpm_unpack(alpm_handle_t *handle, const char *path, const char *prefix,
 		alpm_list_t *list, int breakfirst)
 {
 	int ret = 0;
 	mode_t oldmask;
-	struct archive *_archive;
+	struct archive *archive;
 	struct archive_entry *entry;
-	int cwdfd;
-
-	if((_archive = archive_read_new()) == NULL) {
-		RET_ERR(handle, ALPM_ERR_LIBARCHIVE, 1);
-	}
-
-	archive_read_support_compression_all(_archive);
-	archive_read_support_format_all(_archive);
+	struct stat buf;
+	int fd, cwdfd;
 
-	if(archive_read_open_filename(_archive, archive,
-				ALPM_BUFFER_SIZE) != ARCHIVE_OK) {
-		_alpm_log(handle, ALPM_LOG_ERROR, _("could not open file %s: %s\n"), archive,
-				archive_error_string(_archive));
-		RET_ERR(handle, ALPM_ERR_PKG_OPEN, 1);
+	fd = _alpm_open_archive(handle, path, &buf, &archive, ALPM_ERR_PKG_OPEN);
+	if(fd < 0) {
+		return 1;
 	}
 
 	oldmask = umask(0022);
@@ -305,7 +355,7 @@ int _alpm_unpack(alpm_handle_t *handle, const char *archive, const char *prefix,
 		goto cleanup;
 	}
 
-	while(archive_read_next_header(_archive, &entry) == ARCHIVE_OK) {
+	while(archive_read_next_header(archive, &entry) == ARCHIVE_OK) {
 		const char *entryname;
 		mode_t mode;
 
@@ -321,7 +371,7 @@ int _alpm_unpack(alpm_handle_t *handle, const char *archive, const char *prefix,
 			char *found = alpm_list_find_str(list, entry_prefix);
 			free(entry_prefix);
 			if(!found) {
-				if(archive_read_data_skip(_archive) != ARCHIVE_OK) {
+				if(archive_read_data_skip(archive) != ARCHIVE_OK) {
 					ret = 1;
 					goto cleanup;
 				}
@@ -339,14 +389,14 @@ int _alpm_unpack(alpm_handle_t *handle, const char *archive, const char *prefix,
 		}
 
 		/* Extract the archive entry. */
-		int readret = archive_read_extract(_archive, entry, 0);
+		int readret = archive_read_extract(archive, entry, 0);
 		if(readret == ARCHIVE_WARN) {
 			/* operation succeeded but a non-critical error was encountered */
 			_alpm_log(handle, ALPM_LOG_WARNING, _("warning given when extracting %s (%s)\n"),
-					entryname, archive_error_string(_archive));
+					entryname, archive_error_string(archive));
 		} else if(readret != ARCHIVE_OK) {
 			_alpm_log(handle, ALPM_LOG_ERROR, _("could not extract %s (%s)\n"),
-					entryname, archive_error_string(_archive));
+					entryname, archive_error_string(archive));
 			ret = 1;
 			goto cleanup;
 		}
@@ -358,7 +408,8 @@ int _alpm_unpack(alpm_handle_t *handle, const char *archive, const char *prefix,
 
 cleanup:
 	umask(oldmask);
-	archive_read_finish(_archive);
+	archive_read_finish(archive);
+	CLOSE(fd);
 	if(cwdfd >= 0) {
 		if(fchdir(cwdfd) != 0) {
 			_alpm_log(handle, ALPM_LOG_ERROR,