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authorDavid Oberhollenzer <david.oberhollenzer@sigma-star.at>2019-06-29 02:26:11 +0200
committerDavid Oberhollenzer <david.oberhollenzer@sigma-star.at>2019-06-29 02:26:57 +0200
commit8c449c503f4c37f72089a0dc50e00631a22ed12a (patch)
treee280aabfca0b5c12cafde614883aa05a17fa719e
parentd2f27dc653767f36885916d9ecd7b059673d26d8 (diff)
Add support for reading old style GNU sparse tar file format
Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>
-rw-r--r--include/tar.h17
-rw-r--r--lib/tar/read_header.c116
-rw-r--r--tests/Makemodule.am8
-rw-r--r--tests/tar_sparse_gnu.c127
4 files changed, 266 insertions, 2 deletions
diff --git a/include/tar.h b/include/tar.h
index 4da04f5..6fdb22d 100644
--- a/include/tar.h
+++ b/include/tar.h
@@ -53,9 +53,25 @@ typedef struct {
} tar_header_t;
typedef struct {
+ struct {
+ char offset[12];
+ char numbytes[12];
+ } sparse[21];
+ char isextended;
+ char padding[7];
+} gnu_sparse_t;
+
+typedef struct tar_sparse_data_t {
+ struct tar_sparse_data_t *next;
+ uint64_t offset;
+ uint64_t count;
+} tar_sparse_data_t;
+
+typedef struct {
struct stat sb;
char *name;
char *link_target;
+ tar_sparse_data_t *sparse;
bool unknown_record;
} tar_header_decoded_t;
@@ -69,6 +85,7 @@ typedef struct {
#define TAR_TYPE_GNU_SLINK 'K'
#define TAR_TYPE_GNU_PATH 'L'
+#define TAR_TYPE_GNU_SPARSE 'S'
#define TAR_TYPE_PAX 'x'
diff --git a/lib/tar/read_header.c b/lib/tar/read_header.c
index 76634e1..44a38f9 100644
--- a/lib/tar/read_header.c
+++ b/lib/tar/read_header.c
@@ -390,6 +390,7 @@ static int decode_header(const tar_header_t *hdr, unsigned int set_by_pax,
switch (hdr->typeflag) {
case '\0':
case TAR_TYPE_FILE:
+ case TAR_TYPE_GNU_SPARSE:
out->sb.st_mode |= S_IFREG;
break;
case TAR_TYPE_LINK:
@@ -450,6 +451,104 @@ fail:
return NULL;
}
+static void free_sparse_list(tar_sparse_data_t *sparse)
+{
+ tar_sparse_data_t *old;
+
+ while (sparse != NULL) {
+ old = sparse;
+ sparse = sparse->next;
+ free(old);
+ }
+}
+
+static tar_sparse_data_t *read_gnu_old_sparse(int fd, tar_header_t *hdr)
+{
+ tar_sparse_data_t *list = NULL, *end = NULL, *node;
+ gnu_sparse_t sph;
+ uint64_t off, sz;
+ ssize_t ret;
+ int i;
+
+ for (i = 0; i < 4; ++i) {
+ if (!isdigit(hdr->tail.gnu.sparse[i].offset[0]))
+ break;
+ if (!isdigit(hdr->tail.gnu.sparse[i].numbytes[0]))
+ break;
+
+ if (read_octal(hdr->tail.gnu.sparse[i].offset,
+ sizeof(hdr->tail.gnu.sparse[i].offset), &off))
+ goto fail;
+ if (read_octal(hdr->tail.gnu.sparse[i].numbytes,
+ sizeof(hdr->tail.gnu.sparse[i].numbytes), &sz))
+ goto fail;
+
+ node = calloc(1, sizeof(*node));
+ if (node == NULL)
+ goto fail_errno;
+
+ node->offset = off;
+ node->count = sz;
+
+ if (list == NULL) {
+ list = end = node;
+ } else {
+ end->next = node;
+ end = node;
+ }
+ }
+
+ if (hdr->tail.gnu.isextended == 0)
+ return list;
+
+ do {
+ ret = read_retry(fd, &sph, sizeof(sph));
+ if (ret < 0)
+ goto fail_errno;
+ if ((size_t)ret < sizeof(sph))
+ goto fail_eof;
+
+ for (i = 0; i < 21; ++i) {
+ if (!isdigit(sph.sparse[i].offset[0]))
+ break;
+ if (!isdigit(sph.sparse[i].numbytes[0]))
+ break;
+
+ if (read_octal(sph.sparse[i].offset,
+ sizeof(sph.sparse[i].offset), &off))
+ goto fail;
+ if (read_octal(sph.sparse[i].numbytes,
+ sizeof(sph.sparse[i].numbytes), &sz))
+ goto fail;
+
+ node = calloc(1, sizeof(*node));
+ if (node == NULL)
+ goto fail_errno;
+
+ node->offset = off;
+ node->count = sz;
+
+ if (list == NULL) {
+ list = end = node;
+ } else {
+ end->next = node;
+ end = node;
+ }
+ }
+ } while (sph.isextended != 0);
+
+ return list;
+fail_eof:
+ fputs("parsing GNU sparse header: unexpected end of file", stderr);
+ goto fail;
+fail_errno:
+ perror("parsing GNU sparse header");
+ goto fail;
+fail:
+ free_sparse_list(list);
+ return NULL;
+}
+
int read_header(int fd, tar_header_decoded_t *out)
{
unsigned int set_by_pax = 0;
@@ -513,6 +612,22 @@ int read_header(int fd, tar_header_decoded_t *out)
if (read_pax_header(fd, pax_size, &set_by_pax, out))
goto fail;
continue;
+ case TAR_TYPE_GNU_SPARSE:
+ if (!(set_by_pax & PAX_SIZE)) {
+ if (read_number(hdr.tail.gnu.realsize,
+ sizeof(hdr.tail.gnu.realsize),
+ &pax_size))
+ goto fail;
+
+ out->sb.st_size = pax_size;
+ set_by_pax |= PAX_SIZE;
+ }
+
+ free_sparse_list(out->sparse);
+ out->sparse = read_gnu_old_sparse(fd, &hdr);
+ if (out->sparse == NULL)
+ goto fail;
+ break;
}
break;
}
@@ -543,6 +658,7 @@ fail:
void clear_header(tar_header_decoded_t *hdr)
{
+ free_sparse_list(hdr->sparse);
free(hdr->name);
free(hdr->link_target);
memset(hdr, 0, sizeof(*hdr));
diff --git a/tests/Makemodule.am b/tests/Makemodule.am
index e9cb8c4..004f83c 100644
--- a/tests/Makemodule.am
+++ b/tests/Makemodule.am
@@ -46,16 +46,20 @@ test_tar_ustar_SOURCES = tests/tar_ustar.c
test_tar_ustar_LDADD = libtar.a libutil.a
test_tar_ustar_CPPFLAGS = $(AM_CPPFLAGS) -DTESTPATH=$(top_srcdir)/tests/tar
+test_tar_sparse_gnu_SOURCES = tests/tar_sparse_gnu.c
+test_tar_sparse_gnu_LDADD = libtar.a libutil.a
+test_tar_sparse_gnu_CPPFLAGS = $(AM_CPPFLAGS) -DTESTPATH=$(top_srcdir)/tests/tar
+
check_PROGRAMS += test_canonicalize_name test_mknode_simple test_mknode_slink
check_PROGRAMS += test_mknode_reg test_mknode_dir test_gen_inode_table
check_PROGRAMS += test_add_by_path test_get_path test_fstree_sort
check_PROGRAMS += test_fstree_from_file test_fstree_init test_fstree_xattr
-check_PROGRAMS += test_tar_ustar test_tar_pax test_tar_gnu
+check_PROGRAMS += test_tar_ustar test_tar_pax test_tar_gnu test_tar_sparse_gnu
TESTS += test_canonicalize_name test_mknode_simple test_mknode_slink
TESTS += test_mknode_reg test_mknode_dir test_gen_inode_table
TESTS += test_add_by_path test_get_path test_fstree_sort test_fstree_from_file
TESTS += test_fstree_init test_fstree_xattr test_tar_ustar test_tar_pax
-TESTS += test_tar_gnu
+TESTS += test_tar_gnu test_tar_sparse_gnu
EXTRA_DIST += $(top_srcdir)/tests/tar
diff --git a/tests/tar_sparse_gnu.c b/tests/tar_sparse_gnu.c
new file mode 100644
index 0000000..2f2e1c5
--- /dev/null
+++ b/tests/tar_sparse_gnu.c
@@ -0,0 +1,127 @@
+/* SPDX-License-Identifier: GPL-3.0-or-later */
+#include "util.h"
+#include "tar.h"
+
+#include <unistd.h>
+#include <assert.h>
+#include <stdlib.h>
+#include <string.h>
+#include <fcntl.h>
+#include <stdio.h>
+
+#define STR(x) #x
+#define STRVALUE(x) STR(x)
+
+#define TEST_PATH STRVALUE(TESTPATH)
+
+static int open_read(const char *path)
+{
+ int fd = open(path, O_RDONLY);
+
+ if (fd < 0) {
+ perror(path);
+ exit(EXIT_FAILURE);
+ }
+
+ return fd;
+}
+
+int main(void)
+{
+ tar_sparse_data_t *sparse;
+ tar_header_decoded_t hdr;
+ int fd;
+
+ assert(chdir(TEST_PATH) == 0);
+
+ fd = open_read("sparse-files/gnu-small.tar");
+ assert(read_header(fd, &hdr) == 0);
+ assert(hdr.sb.st_mode == (S_IFREG | 0644));
+ assert(hdr.sb.st_uid == 01750);
+ assert(hdr.sb.st_gid == 01750);
+ assert(hdr.sb.st_size == 524288);
+ assert(strcmp(hdr.name, "input.bin") == 0);
+ assert(!hdr.unknown_record);
+
+ sparse = hdr.sparse;
+ assert(sparse != NULL);
+ assert(sparse->offset == 0);
+ assert(sparse->count == 4096);
+
+ sparse = sparse->next;
+ assert(sparse != NULL);
+ assert(sparse->offset == 262144);
+ assert(sparse->count == 4096);
+
+ sparse = sparse->next;
+ assert(sparse != NULL);
+ assert(sparse->offset == 524288);
+ assert(sparse->count == 0);
+
+ assert(sparse->next == NULL);
+
+ clear_header(&hdr);
+ close(fd);
+
+ fd = open_read("sparse-files/gnu.tar");
+ assert(read_header(fd, &hdr) == 0);
+ assert(hdr.sb.st_mode == (S_IFREG | 0644));
+ assert(hdr.sb.st_uid == 01750);
+ assert(hdr.sb.st_gid == 01750);
+ assert(hdr.sb.st_size == 2097152);
+ assert(strcmp(hdr.name, "input.bin") == 0);
+ assert(!hdr.unknown_record);
+
+ sparse = hdr.sparse;
+ assert(sparse != NULL);
+ assert(sparse->offset == 0);
+ assert(sparse->count == 4096);
+
+ sparse = sparse->next;
+ assert(sparse != NULL);
+ assert(sparse->offset == 262144);
+ assert(sparse->count == 4096);
+
+ sparse = sparse->next;
+ assert(sparse != NULL);
+ assert(sparse->offset == 524288);
+ assert(sparse->count == 4096);
+
+ sparse = sparse->next;
+ assert(sparse != NULL);
+ assert(sparse->offset == 786432);
+ assert(sparse->count == 4096);
+
+ sparse = sparse->next;
+ assert(sparse != NULL);
+ assert(sparse->offset == 1048576);
+ assert(sparse->count == 4096);
+
+ sparse = sparse->next;
+ assert(sparse != NULL);
+ assert(sparse->offset == 1310720);
+ assert(sparse->count == 4096);
+
+ sparse = sparse->next;
+ assert(sparse != NULL);
+ assert(sparse->offset == 1572864);
+ assert(sparse->count == 4096);
+
+ sparse = sparse->next;
+ assert(sparse != NULL);
+ assert(sparse->offset == 1835008);
+ assert(sparse->count == 4096);
+
+ sparse = sparse->next;
+ assert(sparse != NULL);
+ assert(sparse->offset == 2097152);
+ assert(sparse->count == 0);
+
+ sparse = sparse->next;
+ assert(sparse == NULL);
+
+ clear_header(&hdr);
+ close(fd);
+
+ return EXIT_SUCCESS;
+}