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-rw-r--r--util-linux/volume_id/squashfs.c59
1 files changed, 59 insertions, 0 deletions
diff --git a/util-linux/volume_id/squashfs.c b/util-linux/volume_id/squashfs.c
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+++ b/util-linux/volume_id/squashfs.c
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+/*
+ * volume_id - reads filesystem label and uuid
+ *
+ * Copyright (C) 2012 S-G Bergh <sgb@systemasis.org>
+ *
+ * Licensed under GPLv2, see file LICENSE in this source tree.
+ */
+
+//config:config FEATURE_VOLUMEID_SQUASHFS
+//config: bool "SquashFS filesystem"
+//config: default y
+//config: depends on VOLUMEID && FEATURE_BLKID_TYPE
+//config: help
+//config: Squashfs is a compressed read-only filesystem for Linux. Squashfs is
+//config: intended for general read-only filesystem use and in constrained block
+//config: device/memory systems (e.g. embedded systems) where low overhead is
+//config: needed.
+
+//kbuild:lib-$(CONFIG_FEATURE_VOLUMEID_SQUASHFS) += squashfs.o
+
+#include "volume_id_internal.h"
+
+struct squashfs_superblock {
+ uint32_t magic;
+/*
+ uint32_t dummy[6];
+ uint16_t major;
+ uint16_t minor;
+*/
+} PACKED;
+
+int FAST_FUNC volume_id_probe_squashfs(struct volume_id *id /*,uint64_t off*/)
+{
+#define off ((uint64_t)0)
+ struct squashfs_superblock *sb;
+
+ dbg("SquashFS: probing at offset 0x%llx", (unsigned long long) off);
+ sb = volume_id_get_buffer(id, off, 0x200);
+ if (!sb)
+ return -1;
+
+ // Old SquashFS (pre 4.0) can be both big and little endian, so test for both.
+ // Likewise, it is commonly used in firwmare with some non-standard signatures.
+#define pack(a,b,c,d) ( (uint32_t)((a * 256 + b) * 256 + c) * 256 + d )
+#define SIG1 pack('s','q','s','h')
+#define SIG2 pack('h','s','q','s')
+#define SIG3 pack('s','h','s','q')
+#define SIG4 pack('q','s','h','s')
+ if (sb->magic == SIG1
+ || sb->magic == SIG2
+ || sb->magic == SIG3
+ || sb->magic == SIG4
+ ) {
+ IF_FEATURE_BLKID_TYPE(id->type = "squashfs";)
+ return 0;
+ }
+
+ return -1;
+}