squashfsTools: apply reproducibility patches

Without these patches, the output of mksquashfs is not reproducible.
The patches are taken from https://github.com/squashfskit/squashfskit,
a fork of squashfs-tools, licensed under the GPL2 or later like
squashfs-tools itself.

4 files changed, 402 insertions, 0 deletions

diff --git a/pkgs/tools/filesystems/squashfs/0001-If-SOURCE_DATE_EPOCH-is-set-override-timestamps-with.patch b/pkgs/tools/filesystems/squashfs/0001-If-SOURCE_DATE_EPOCH-is-set-override-timestamps-with.patch
new file mode 100644
index 00000000000..5626800e723
--- /dev/null
+++ b/pkgs/tools/filesystems/squashfs/0001-If-SOURCE_DATE_EPOCH-is-set-override-timestamps-with.patch
@@ -0,0 +1,90 @@
+From 0ab12a8585373be2de5129e14d979c62e7a90d82 Mon Sep 17 00:00:00 2001
+From: Chris Lamb <lamby@debian.org>
+Date: Mon, 21 Nov 2016 09:33:05 +0100
+Subject: [PATCH] If SOURCE_DATE_EPOCH is set, override timestamps with that
+ value.
+
+See https://reproducible-builds.org/specs/source-date-epoch/ for more
+information about this environment variable.
+
+Based on a patch by Alexander Couzens <lynxis@fe...> posted on
+https://sourceforge.net/p/squashfs/mailman/message/34673610/
+
+Signed-off-by: Chris Lamb <lamby@debian.org>
+---
+ squashfs-tools/mksquashfs.c | 38 ++++++++++++++++++++++++++++++++++++-
+ 1 file changed, 37 insertions(+), 1 deletion(-)
+
+diff --git a/squashfs-tools/mksquashfs.c b/squashfs-tools/mksquashfs.c
+index c2098bd..b49e956 100644
+--- a/squashfs-tools/mksquashfs.c
++++ b/squashfs-tools/mksquashfs.c
+@@ -137,6 +137,9 @@ unsigned int cache_bytes = 0, cache_size = 0, inode_count = 0;
+ /* inode lookup table */
+ squashfs_inode *inode_lookup_table = NULL;
+ 
++/* override filesystem creation time */
++time_t mkfs_fixed_time = -1;
++
+ /* in memory directory data */
+ #define I_COUNT_SIZE		128
+ #define DIR_ENTRIES		32
+@@ -5104,6 +5107,9 @@ int main(int argc, char *argv[])
+ 	int total_mem = get_default_phys_mem();
+ 	int progress = TRUE;
+ 	int force_progress = FALSE;
++	char *source_date_epoch, *endptr;
++	unsigned long long epoch;
++
+ 	struct file_buffer **fragment = NULL;
+ 
+ 	if(argc > 1 && strcmp(argv[1], "-version") == 0) {
+@@ -5641,6 +5647,36 @@ printOptions:
+ 		}
+ 	}
+ 
++	/* if SOURCE_DATE_EPOCH is set, use that timestamp for the mkfs time */
++	source_date_epoch = getenv("SOURCE_DATE_EPOCH");
++	if(source_date_epoch) {
++		errno = 0;
++		epoch = strtoull(source_date_epoch, &endptr, 10);
++		if((errno == ERANGE && (epoch == ULLONG_MAX || epoch == 0))
++				|| (errno != 0 && epoch == 0)) {
++			ERROR("Environment variable $SOURCE_DATE_EPOCH: "
++				"strtoull: %s\n", strerror(errno));
++			EXIT_MKSQUASHFS();
++		}
++		if(endptr == source_date_epoch) {
++			ERROR("Environment variable $SOURCE_DATE_EPOCH: "
++				"No digits were found: %s\n", endptr);
++			EXIT_MKSQUASHFS();
++		}
++		if(*endptr != '\0') {
++			ERROR("Environment variable $SOURCE_DATE_EPOCH: "
++				"Trailing garbage: %s\n", endptr);
++			EXIT_MKSQUASHFS();
++		}
++		if(epoch > ULONG_MAX) {
++			ERROR("Environment variable $SOURCE_DATE_EPOCH: "
++				"value must be smaller than or equal to "
++				"%lu but was found to be: %llu \n", ULONG_MAX, epoch);
++			EXIT_MKSQUASHFS();
++		}
++		mkfs_fixed_time = (time_t)epoch;
++	}
++
+ 	/*
+ 	 * Some compressors may need the options to be checked for validity
+ 	 * once all the options have been processed
+@@ -5993,7 +6029,7 @@ printOptions:
+	sBlk.flags = SQUASHFS_MKFLAGS(noI, noD, noF, noX, no_fragments,
+		always_use_fragments, duplicate_checking, exportable,
+		no_xattrs, comp_opts);
+-	sBlk.mkfs_time = time(NULL);
++	sBlk.mkfs_time = mkfs_fixed_time != -1 ? mkfs_fixed_time : time(NULL);
+ 
+ 	disable_info();
+ 
+-- 
+2.17.0
+
diff --git a/pkgs/tools/filesystems/squashfs/0002-If-SOURCE_DATE_EPOCH-is-set-also-clamp-content-times.patch b/pkgs/tools/filesystems/squashfs/0002-If-SOURCE_DATE_EPOCH-is-set-also-clamp-content-times.patch
new file mode 100644
index 00000000000..5002375887f
--- /dev/null
+++ b/pkgs/tools/filesystems/squashfs/0002-If-SOURCE_DATE_EPOCH-is-set-also-clamp-content-times.patch
@@ -0,0 +1,83 @@
+From 32a07d4156a281084c90a4b78affc8b0b32a26fc Mon Sep 17 00:00:00 2001
+From: intrigeri <intrigeri@boum.org>
+Date: Mon, 21 Nov 2016 11:41:28 +0000
+Subject: [PATCH] If SOURCE_DATE_EPOCH is set, also clamp content timestamps
+ with that value.
+
+Based on a patch by Alexander Couzens <lynxis@fe...> posted on
+https://sourceforge.net/p/squashfs/mailman/message/34673610/
+---
+ squashfs-tools/mksquashfs.c | 15 ++++++++++++---
+ 1 file changed, 12 insertions(+), 3 deletions(-)
+
+diff --git a/squashfs-tools/mksquashfs.c b/squashfs-tools/mksquashfs.c
+index b49e956..9f020bf 100644
+--- a/squashfs-tools/mksquashfs.c
++++ b/squashfs-tools/mksquashfs.c
+@@ -137,6 +137,9 @@ unsigned int cache_bytes = 0, cache_size = 0, inode_count = 0;
+ /* inode lookup table */
+ squashfs_inode *inode_lookup_table = NULL;
+ 
++/* clamp all timestamps to SOURCE_DATE_EPOCH */
++time_t content_clamp_time = -1;
++
+ /* override filesystem creation time */
+ time_t mkfs_fixed_time = -1;
+ 
+@@ -2246,6 +2249,8 @@ restat:
+ 			  pathname_reader(dir_ent), strerror(errno));
+ 		goto read_err;
+ 	}
++	if(content_clamp_time != -1 && buf2.st_mtime >= content_clamp_time)
++		buf2.st_mtime = content_clamp_time;
+ 
+ 	if(read_size != buf2.st_size) {
+ 		close(file);
+@@ -3101,7 +3106,7 @@ void dir_scan(squashfs_inode *inode, char *pathname,
+ 		buf.st_mode = S_IRWXU | S_IRWXG | S_IRWXO | S_IFDIR;
+ 		buf.st_uid = getuid();
+ 		buf.st_gid = getgid();
+-		buf.st_mtime = time(NULL);
++		buf.st_mtime = content_clamp_time != -1 ? content_clamp_time : time(NULL);
+ 		buf.st_dev = 0;
+ 		buf.st_ino = 0;
+ 		dir_ent->inode = lookup_inode2(&buf, PSEUDO_FILE_OTHER, 0);
+@@ -3127,6 +3115,8 @@ void dir_scan(squashfs_inode *inode, char *pathname,
+			/* source directory has disappeared? */
+			BAD_ERROR("Cannot stat source directory %s because %s\n",
+				pathname, strerror(errno));
++		if(content_clamp_time != -1 && buf.st_mtime >= content_clamp_time)
++			buf.st_mtime = content_clamp_time;
+ 		dir_ent->inode = lookup_inode(&buf);
+ 	}
+ 
+@@ -3365,6 +3372,8 @@ struct dir_info *dir_scan1(char *filename, char *subpath,
+ 			free_dir_entry(dir_ent);
+ 			continue;
+ 		}
++		if(content_clamp_time != -1 && buf.st_mtime >= content_clamp_time)
++			buf.st_mtime = content_clamp_time;
+ 
+ 		if((buf.st_mode & S_IFMT) != S_IFREG &&
+ 				(buf.st_mode & S_IFMT) != S_IFDIR &&
+@@ -3544,7 +3553,7 @@ void dir_scan2(struct dir_info *dir, struct pseudo *pseudo)
+		buf.st_gid = pseudo_ent->dev->gid;
+		buf.st_rdev = makedev(pseudo_ent->dev->major,
+			pseudo_ent->dev->minor);
+-		buf.st_mtime = time(NULL);
++		buf.st_mtime = content_clamp_time != -1 ? content_clamp_time : time(NULL);
+ 		buf.st_ino = pseudo_ino ++;
+ 
+ 		if(pseudo_ent->dev->type == 'd') {
+@@ -5674,7 +5683,7 @@ printOptions:
+ 				"%lu but was found to be: %llu \n", ULONG_MAX, epoch);
+ 			EXIT_MKSQUASHFS();
+ 		}
+-		mkfs_fixed_time = (time_t)epoch;
++		mkfs_fixed_time = content_clamp_time = (time_t)epoch;
+ 	}
+ 
+ 	/*
+-- 
+2.17.0
+
diff --git a/pkgs/tools/filesystems/squashfs/0003-remove-frag-deflator-thread.patch b/pkgs/tools/filesystems/squashfs/0003-remove-frag-deflator-thread.patch
new file mode 100644
index 00000000000..4be4b96369a
--- /dev/null
+++ b/pkgs/tools/filesystems/squashfs/0003-remove-frag-deflator-thread.patch
@@ -0,0 +1,220 @@
+From afc0c76a170bd17cbd29bbec6ae6d2227e398570 Mon Sep 17 00:00:00 2001
+From: Alexander Couzens <lynxis@fe80.eu>
+Date: Fri, 13 Jan 2017 22:00:37 +0100
+Subject: [PATCH] remove frag_deflator_thread
+
+frag_deflator_thread compress fragments.
+Replace the deflator_thread with a function and
+use the function instead of the to_frag queue.
+---
+ squashfs-tools/info.c       |  5 ---
+ squashfs-tools/mksquashfs.c | 76 +++++++++++++------------------------
+ squashfs-tools/mksquashfs.h |  2 +-
+ squashfs-tools/restore.c    | 15 +-------
+ 4 files changed, 30 insertions(+), 68 deletions(-)
+
+diff --git a/squashfs-tools/info.c b/squashfs-tools/info.c
+index 7968c77..028d578 100644
+--- a/squashfs-tools/info.c
++++ b/squashfs-tools/info.c
+@@ -96,11 +96,6 @@ void dump_state()
+ 	printf("compressed block queue (deflate thread(s) -> main thread)\n");
+ 	dump_seq_queue(to_main, 0);
+ 
+-	printf("uncompressed packed fragment queue (main thread -> fragment"
+-						" deflate thread(s))\n");
+-	dump_queue(to_frag);
+-
+-
+ 	printf("locked frag queue (compressed frags waiting while multi-block"
+ 						" file is written)\n");
+ 	dump_queue(locked_fragment);
+diff --git a/squashfs-tools/mksquashfs.c b/squashfs-tools/mksquashfs.c
+index cf48e40..cacf14c 100644
+--- a/squashfs-tools/mksquashfs.c
++++ b/squashfs-tools/mksquashfs.c
+@@ -270,10 +270,10 @@ unsigned int sid_count = 0, suid_count = 0, sguid_count = 0;
+ struct cache *reader_buffer, *fragment_buffer, *reserve_cache;
+ struct cache *bwriter_buffer, *fwriter_buffer;
+ struct queue *to_reader, *to_deflate, *to_writer, *from_writer,
+-	*to_frag, *locked_fragment, *to_process_frag;
++	*locked_fragment, *to_process_frag;
+ struct seq_queue *to_main;
+ pthread_t reader_thread, writer_thread, main_thread;
+-pthread_t *deflator_thread, *frag_deflator_thread, *frag_thread;
++pthread_t *deflator_thread, *frag_thread;
+ pthread_t *restore_thread = NULL;
+ pthread_mutex_t	fragment_mutex = PTHREAD_MUTEX_INITIALIZER;
+ pthread_mutex_t	pos_mutex = PTHREAD_MUTEX_INITIALIZER;
+@@ -323,7 +323,7 @@ struct dir_info *scan1_opendir(char *pathname, char *subpath, int depth);
+ void write_filesystem_tables(struct squashfs_super_block *sBlk, int nopad);
+ unsigned short get_checksum_mem(char *buff, int bytes);
+ void check_usable_phys_mem(int total_mem);
+-
++void frag_deflator(struct file_buffer *file_buffer);
+ 
+ void prep_exit()
+ {
+@@ -1540,7 +1540,7 @@ void write_fragment(struct file_buffer *fragment)
+ 	pthread_mutex_lock(&fragment_mutex);
+ 	fragment_table[fragment->block].unused = 0;
+ 	fragments_outstanding ++;
+-	queue_put(to_frag, fragment);
++	frag_deflator(fragment);
+ 	pthread_cleanup_pop(1);
+ }
+ 
+@@ -2412,51 +2412,34 @@ void *deflator(void *arg)
+ }
+ 
+ 
+-void *frag_deflator(void *arg)
++void frag_deflator(struct file_buffer *file_buffer)
+ {
+-	void *stream = NULL;
+-	int res;
+ 
+-	res = compressor_init(comp, &stream, block_size, 1);
+-	if(res)
+-		BAD_ERROR("frag_deflator:: compressor_init failed\n");
+-
+-	pthread_cleanup_push((void *) pthread_mutex_unlock, &fragment_mutex);
+-
+-	while(1) {
+-		int c_byte, compressed_size;
+-		struct file_buffer *file_buffer = queue_get(to_frag);
+-		struct file_buffer *write_buffer =
++	int c_byte, compressed_size;
++	struct file_buffer *write_buffer =
+ 			cache_get(fwriter_buffer, file_buffer->block);
+ 
+-		c_byte = mangle2(stream, write_buffer->data, file_buffer->data,
+-			file_buffer->size, block_size, noF, 1);
+-		compressed_size = SQUASHFS_COMPRESSED_SIZE_BLOCK(c_byte);
+-		write_buffer->size = compressed_size;
+-		pthread_mutex_lock(&fragment_mutex);
+-		if(fragments_locked == FALSE) {
+-			fragment_table[file_buffer->block].size = c_byte;
+-			fragment_table[file_buffer->block].start_block = bytes;
+-			write_buffer->block = bytes;
+-			bytes += compressed_size;
+-			fragments_outstanding --;
+-			queue_put(to_writer, write_buffer);
+-			pthread_mutex_unlock(&fragment_mutex);
+-			TRACE("Writing fragment %lld, uncompressed size %d, "
+-				"compressed size %d\n", file_buffer->block,
+-				file_buffer->size, compressed_size);
+-		} else {
+-				add_pending_fragment(write_buffer, c_byte,
+-					file_buffer->block);
+-				pthread_mutex_unlock(&fragment_mutex);
+-		}
+-		cache_block_put(file_buffer);
++	c_byte = mangle2(stream, write_buffer->data, file_buffer->data,
++			 file_buffer->size, block_size, noF, 1);
++	compressed_size = SQUASHFS_COMPRESSED_SIZE_BLOCK(c_byte);
++	write_buffer->size = compressed_size;
++	if(fragments_locked == FALSE) {
++		fragment_table[file_buffer->block].size = c_byte;
++		fragment_table[file_buffer->block].start_block = bytes;
++		write_buffer->block = bytes;
++		bytes += compressed_size;
++		fragments_outstanding --;
++		queue_put(to_writer, write_buffer);
++		TRACE("Writing fragment %lld, uncompressed size %d, "
++		      "compressed size %d\n", file_buffer->block,
++		      file_buffer->size, compressed_size);
++	} else {
++		add_pending_fragment(write_buffer, c_byte,
++				     file_buffer->block);
+ 	}
+-
+-	pthread_cleanup_pop(0);
++	cache_block_put(file_buffer);
+ }
+ 
+-
+ struct file_buffer *get_file_buffer()
+ {
+ 	struct file_buffer *file_buffer = seq_queue_get(to_main);
+@@ -4257,19 +4240,17 @@ void initialise_threads(int readq, int fragq, int bwriteq, int fwriteq,
+ 			multiply_overflow(processors * 3, sizeof(pthread_t)))
+ 		BAD_ERROR("Processors too large\n");
+ 
+-	deflator_thread = malloc(processors * 3 * sizeof(pthread_t));
++	deflator_thread = malloc(processors * 2 * sizeof(pthread_t));
+ 	if(deflator_thread == NULL)
+ 		MEM_ERROR();
+ 
+-	frag_deflator_thread = &deflator_thread[processors];
+-	frag_thread = &frag_deflator_thread[processors];
++	frag_thread = &deflator_thread[processors];
+ 
+ 	to_reader = queue_init(1);
+ 	to_deflate = queue_init(reader_size);
+ 	to_process_frag = queue_init(reader_size);
+ 	to_writer = queue_init(bwriter_size + fwriter_size);
+ 	from_writer = queue_init(1);
+-	to_frag = queue_init(fragment_size);
+ 	locked_fragment = queue_init(fragment_size);
+ 	to_main = seq_queue_init();
+ 	reader_buffer = cache_init(block_size, reader_size, 0, 0);
+@@ -4285,9 +4266,6 @@ void initialise_threads(int readq, int fragq, int bwriteq, int fwriteq,
+ 	for(i = 0; i < processors; i++) {
+ 		if(pthread_create(&deflator_thread[i], NULL, deflator, NULL))
+ 			BAD_ERROR("Failed to create thread\n");
+-		if(pthread_create(&frag_deflator_thread[i], NULL, frag_deflator,
+-				NULL) != 0)
+-			BAD_ERROR("Failed to create thread\n");
+ 		if(pthread_create(&frag_thread[i], NULL, frag_thrd,
+ 				(void *) destination_file) != 0)
+ 			BAD_ERROR("Failed to create thread\n");
+diff --git a/squashfs-tools/mksquashfs.h b/squashfs-tools/mksquashfs.h
+index 55708a3..dc5bde4 100644
+--- a/squashfs-tools/mksquashfs.h
++++ b/squashfs-tools/mksquashfs.h
+@@ -135,7 +135,7 @@ struct append_file {
+ extern struct cache *reader_buffer, *fragment_buffer, *reserve_cache;
+ struct cache *bwriter_buffer, *fwriter_buffer;
+ extern struct queue *to_reader, *to_deflate, *to_writer, *from_writer,
+-	*to_frag, *locked_fragment, *to_process_frag;
++	*locked_fragment, *to_process_frag;
+ extern struct append_file **file_mapping;
+ extern struct seq_queue *to_main;
+ extern pthread_mutex_t fragment_mutex, dup_mutex;
+diff --git a/squashfs-tools/restore.c b/squashfs-tools/restore.c
+index 5e336b3..a7aaf2e 100644
+--- a/squashfs-tools/restore.c
++++ b/squashfs-tools/restore.c
+@@ -47,8 +47,8 @@
+ #define TRUE 1
+ 
+ extern pthread_t reader_thread, writer_thread, main_thread;
+-extern pthread_t *deflator_thread, *frag_deflator_thread, *frag_thread;
+-extern struct queue *to_deflate, *to_writer, *to_frag, *to_process_frag;
++extern pthread_t *deflator_thread, *frag_thread;
++extern struct queue *to_deflate, *to_writer, *to_process_frag;
+ extern struct seq_queue *to_main;
+ extern void restorefs();
+ extern int processors;
+@@ -120,17 +120,6 @@ void *restore_thrd(void *arg)
+ 		pthread_cancel(main_thread);
+ 		pthread_join(main_thread, NULL);
+ 
+-		/* then flush the main thread to fragment deflator thread(s)
+-		 * queue.  The fragment deflator thread(s) will idle
+-		 */
+-		queue_flush(to_frag);
+-
+-		/* now kill the fragment deflator thread(s) */
+-		for(i = 0; i < processors; i++)
+-			pthread_cancel(frag_deflator_thread[i]);
+-		for(i = 0; i < processors; i++)
+-			pthread_join(frag_deflator_thread[i], NULL);
+-
+ 		/*
+ 		 * then flush the main thread/fragment deflator thread(s)
+ 		 * to writer thread queue.  The writer thread will idle
+-- 
+2.17.0
+
diff --git a/pkgs/tools/filesystems/squashfs/default.nix b/pkgs/tools/filesystems/squashfs/default.nix
index a2fc5bc3d40..08951113b3b 100644
--- a/pkgs/tools/filesystems/squashfs/default.nix
+++ b/pkgs/tools/filesystems/squashfs/default.nix
@@ -15,6 +15,15 @@ stdenv.mkDerivation rec {
     rev = "9c1db6d13a51a2e009f0027ef336ce03624eac0d";
   };
 
+  # These patches ensures that mksquashfs output is reproducible.
+  # See also https://reproducible-builds.org/docs/system-images/
+  # and https://github.com/NixOS/nixpkgs/issues/40144.
+  patches = [
+    ./0001-If-SOURCE_DATE_EPOCH-is-set-override-timestamps-with.patch
+    ./0002-If-SOURCE_DATE_EPOCH-is-set-also-clamp-content-times.patch
+    ./0003-remove-frag-deflator-thread.patch
+  ];
+
   buildInputs = [ zlib xz ]
     ++ stdenv.lib.optional lz4Support lz4;