Overhaul sqfs_istream_t/sqfs_ostream_t error handling

Report an error number from the implementations, change the users to
forward that error number (which also means libtar write header/link
now returns an error code) and all subsequent binaries to use
sqfs_perror() instead of relying on the function to print an error
internally.

Also, make sure to preserve errno/GetLastError() in the implementations
and print out a stringified error in sqfs_perror() if the error code
indicates an I/O error.

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

2 files changed, 15 insertions, 6 deletions

diff --git a/bin/rdsquashfs/src/fill_files.c b/bin/rdsquashfs/src/fill_files.c
index e692ee3..f0ad7e2 100644
--- a/bin/rdsquashfs/src/fill_files.c
+++ b/bin/rdsquashfs/src/fill_files.c
@@ -145,9 +145,11 @@ static int fill_files(sqfs_data_reader_t *data, int flags)
 		openflags |= SQFS_FILE_OPEN_NO_SPARSE;
 
 	for (i = 0; i < num_files; ++i) {
-		fp = ostream_open_file(files[i].path, openflags);
-		if (fp == NULL)
+		ret = ostream_open_file(&fp, files[i].path, openflags);
+		if (ret) {
+			sqfs_perror(files[i].path, NULL, ret);
 			return -1;
+		}
 
 		if (!(flags & UNPACK_QUIET))
 			printf("unpacking %s\n", files[i].path);
@@ -157,9 +159,13 @@ static int fill_files(sqfs_data_reader_t *data, int flags)
 		if (ret == 0)
 			ret = fp->flush(fp);
 
-		sqfs_drop(fp);
-		if (ret)
+		if (ret) {
+			sqfs_perror(files[i].path, "unpacking", ret);
+			sqfs_drop(fp);
 			return -1;
+		}
+
+		sqfs_drop(fp);
 	}
 
 	return 0;
diff --git a/bin/rdsquashfs/src/rdsquashfs.c b/bin/rdsquashfs/src/rdsquashfs.c
index ad85e68..77dc5ba 100644
--- a/bin/rdsquashfs/src/rdsquashfs.c
+++ b/bin/rdsquashfs/src/rdsquashfs.c
@@ -208,6 +208,7 @@ int main(int argc, char **argv)
 		break;
 	case OP_CAT: {
 		sqfs_ostream_t *fp;
+		int ret;
 
 		if (!S_ISREG(n->inode->base.mode)) {
 			fprintf(stderr, "/%s: not a regular file\n",
@@ -215,9 +216,11 @@ int main(int argc, char **argv)
 			goto out;
 		}
 
-		fp = ostream_open_stdout();
-		if (fp == NULL)
+		ret = ostream_open_stdout(&fp);
+		if (ret) {
+			sqfs_perror("stdout", "creating stream wrapper", ret);
 			goto out;
+		}
 
 		ret = sqfs_data_reader_dump(opt.cmdpath, data, n->inode,
 					    fp, super.block_size);