Cleanup: unify packdir/packfile based directory changes in gensquashfs

This commit removes the packdir/packfile based directory setup magic
from fstree_from_file and moves it to gensquashfs. Over there, the
common parts are deduplicated.

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

3 files changed, 60 insertions, 61 deletions

diff --git a/include/fstree.h b/include/fstree.h
index 74d1c7f..784364e 100644
--- a/include/fstree.h
+++ b/include/fstree.h
@@ -7,6 +7,7 @@
 #include <stdbool.h>
 #include <stdint.h>
 #include <stddef.h>
+#include <stdio.h>
 
 #include "str_table.h"
 
@@ -215,19 +216,18 @@ void fstree_xattr_deduplicate(fstree_t *fs);
 
 /*
   Parses the file format accepted by gensquashfs and produce a file system
-  tree from it. File input paths are interpreted as relative to the given
-  root dir. If rootdir is NULL, use the path where the input file is as root
-  dir.
+  tree from it. File input paths are interpreted as relative to the current
+  working directory.
 
-  This function tries to temporarily change the working directory, so if it
-  fails, the current working directory is undefined.
+  Data is read from the given file pointer. The filename is only used for
+  producing error messages.
 
   On failure, an error report with filename and line number is written
   to stderr.
 
   Returns 0 on success.
  */
-int fstree_from_file(fstree_t *fs, const char *filename, const char *rootdir);
+int fstree_from_file(fstree_t *fs, const char *filename, FILE *fp);
 
 /*
   Recursively scan a directory and generate a file system tree from it.
diff --git a/lib/fstree/fstree_from_file.c b/lib/fstree/fstree_from_file.c
index ded404a..0031c09 100644
--- a/lib/fstree/fstree_from_file.c
+++ b/lib/fstree/fstree_from_file.c
@@ -8,7 +8,6 @@
 #include <stdlib.h>
 #include <stdint.h>
 #include <string.h>
-#include <stdio.h>
 #include <ctype.h>
 #include <errno.h>
 
@@ -258,36 +257,12 @@ out_desc:
 	return -1;
 }
 
-int fstree_from_file(fstree_t *fs, const char *filename, const char *rootdir)
+int fstree_from_file(fstree_t *fs, const char *filename, FILE *fp)
 {
-	FILE *fp = fopen(filename, "rb");
-	bool need_restore = false;
 	size_t n, line_num = 0;
-	const char *ptr;
 	ssize_t ret;
 	char *line;
 
-	if (fp == NULL) {
-		perror(filename);
-		return -1;
-	}
-
-	if (rootdir == NULL) {
-		ptr = strrchr(filename, '/');
-
-		if (ptr != NULL) {
-			if (pushdn(filename, ptr - filename)) {
-				free(line);
-				return -1;
-			}
-			need_restore = true;
-		}
-	} else {
-		if (pushd(rootdir))
-			return -1;
-		need_restore = true;
-	}
-
 	for (;;) {
 		line = NULL;
 		n = 0;
@@ -318,15 +293,8 @@ int fstree_from_file(fstree_t *fs, const char *filename, const char *rootdir)
 
 		free(line);
 	}
-
-	fclose(fp);
-
-	if (need_restore && popd() != 0)
-		return -1;
-
 	return 0;
 fail_line:
 	free(line);
-	fclose(fp);
 	return -1;
 }
diff --git a/mkfs/mkfs.c b/mkfs/mkfs.c
index 12b4de9..371c578 100644
--- a/mkfs/mkfs.c
+++ b/mkfs/mkfs.c
@@ -39,25 +39,32 @@ static int pack_files_dfs(data_writer_t *data, tree_node_t *n, bool quiet)
 	return 0;
 }
 
-static int pack_files(data_writer_t *data, fstree_t *fs, options_t *opt)
+static int set_working_dir(options_t *opt)
 {
-	bool need_restore = false;
 	const char *ptr;
 
-	if (opt->packdir != NULL) {
-		if (pushd(opt->packdir))
-			return -1;
-		need_restore = true;
-	} else {
-		ptr = strrchr(opt->infile, '/');
+	if (opt->packdir != NULL)
+		return pushd(opt->packdir);
 
-		if (ptr != NULL) {
-			if (pushdn(opt->infile, ptr - opt->infile))
-				return -1;
+	ptr = strrchr(opt->infile, '/');
+	if (ptr != NULL)
+		return pushdn(opt->infile, ptr - opt->infile);
 
-			need_restore = true;
-		}
-	}
+	return 0;
+}
+
+static int restore_working_dir(options_t *opt)
+{
+	if (opt->packdir != NULL || strrchr(opt->infile, '/') != NULL)
+		return popd();
+
+	return 0;
+}
+
+static int pack_files(data_writer_t *data, fstree_t *fs, options_t *opt)
+{
+	if (set_working_dir(opt))
+		return -1;
 
 	if (pack_files_dfs(data, fs->root, opt->quiet))
 		return -1;
@@ -65,7 +72,36 @@ static int pack_files(data_writer_t *data, fstree_t *fs, options_t *opt)
 	if (data_writer_flush_fragments(data))
 		return -1;
 
-	return need_restore ? popd() : 0;
+	return restore_working_dir(opt);
+}
+
+static int read_fstree(fstree_t *fs, options_t *opt)
+{
+	FILE *fp;
+	int ret;
+
+	if (opt->infile == NULL)
+		return fstree_from_dir(fs, opt->packdir);
+
+	fp = fopen(opt->infile, "rb");
+	if (fp == NULL) {
+		perror(opt->infile);
+		return -1;
+	}
+
+	if (set_working_dir(opt)) {
+		fclose(fp);
+		return -1;
+	}
+
+	ret = fstree_from_file(fs, opt->infile, fp);
+
+	fclose(fp);
+
+	if (restore_working_dir(opt))
+		return -1;
+
+	return ret;
 }
 
 int main(int argc, char **argv)
@@ -101,13 +137,8 @@ int main(int argc, char **argv)
 		goto out_outfd;
 	}
 
-	if (opt.infile != NULL) {
-		if (fstree_from_file(&fs, opt.infile, opt.packdir))
-			goto out_fstree;
-	} else {
-		if (fstree_from_dir(&fs, opt.packdir))
-			goto out_fstree;
-	}
+	if (read_fstree(&fs, &opt))
+		goto out_fstree;
 
 	tree_node_sort_recursive(fs.root);