Implement simple, fork() based parallel unpacking in rdsquashfs

Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>

1 files changed, 93 insertions, 2 deletions

diff --git a/unpack/fill_files.c b/unpack/fill_files.c
index 6584699..865d050 100644
--- a/unpack/fill_files.c
+++ b/unpack/fill_files.c
@@ -33,7 +33,98 @@ static int fill_files(data_reader_t *data, file_info_t *list, int flags)
 	return 0;
 }
 
-int fill_unpacked_files(fstree_t *fs, data_reader_t *data, int flags)
+static file_info_t *split_list(file_info_t *list, uint64_t threashold)
 {
-	return fill_files(data, fs->files, flags);
+	file_info_t *it, *new = NULL;
+	uint64_t size = 0;
+
+	for (it = list; it != NULL; it = it->next) {
+		if (it->input_file == NULL)
+			continue;
+
+		size += it->size - it->sparse;
+
+		if (size >= threashold) {
+			new = it->next;
+			it->next = NULL;
+			break;
+		}
+	}
+
+	return new;
+}
+
+static uint64_t total_size(file_info_t *list)
+{
+	uint64_t size = 0;
+	file_info_t *it;
+
+	for (it = list; it != NULL; it = it->next) {
+		if (it->input_file != NULL)
+			size += it->size - it->sparse;
+	}
+
+	return size;
+}
+
+int fill_unpacked_files(fstree_t *fs, data_reader_t *data, int flags,
+			unsigned int num_jobs)
+{
+	file_info_t *sublists[num_jobs], *it;
+	int exitstatus, status = 0;
+	uint64_t threshold;
+	unsigned int i;
+	pid_t pid;
+
+	if (num_jobs <= 1) {
+		status = fill_files(data, fs->files, flags);
+
+		for (it = fs->files; it != NULL; it = it->next)
+			free(it->input_file);
+
+		return status;
+	}
+
+	threshold = total_size(fs->files) / num_jobs;
+
+	for (i = 0; i < num_jobs; ++i) {
+		sublists[i] = fs->files;
+
+		fs->files = split_list(fs->files, threshold);
+	}
+
+	for (i = 0; i < num_jobs; ++i) {
+		pid = fork();
+
+		if (pid == 0) {
+			if (fill_files(data, sublists[i], flags))
+				exit(EXIT_FAILURE);
+			exit(EXIT_SUCCESS);
+		}
+
+		if (pid < 0) {
+			perror("fork");
+			status = -1;
+			num_jobs = i;
+			break;
+		}
+	}
+
+	for (i = 0; i < num_jobs; ++i) {
+		do {
+			pid = waitpid(-1, &exitstatus, 0);
+			if (errno == ECHILD)
+				goto out;
+		} while (pid < 0);
+
+		if (!WIFEXITED(exitstatus) ||
+		    WEXITSTATUS(exitstatus) != EXIT_SUCCESS) {
+			status = -1;
+		}
+
+		for (it = sublists[i]; it != NULL; it = it->next)
+			free(it->input_file);
+	}
+out:
+	return status;
 }