tar + gzip/bzip2/etc: support NOMMU machines (by Alex Landau <landau_alex@yahoo.com>)

archival/bbunzip.c

@@ -298,7 +298,7 @@ USE_DESKTOP(long long) int unpack_unlzma(void)
 int unlzma_main(int argc, char **argv);
 int unlzma_main(int argc, char **argv)
 {
-	getopt32(argv, "c");
+	getopt32(argv, "cf");
 	argv += optind;
 	/* lzmacat? */
 	if (applet_name[4] == 'c')

archival/libunarchive/Kbuild

@@ -35,7 +35,6 @@ DPKG_FILES:= \
 	get_header_tar.o \
 	filter_accept_list_reassign.o
 
-# open_transformer uses fork(). Compile it only if absolutely necessary
 lib-$(CONFIG_RPM)                       += open_transformer.o
 lib-$(CONFIG_FEATURE_TAR_BZIP2)         += open_transformer.o
 lib-$(CONFIG_FEATURE_TAR_LZMA)          += open_transformer.o
@@ -67,4 +66,3 @@ lib-$(CONFIG_FEATURE_TAR_COMPRESS)	+= decompress_uncompress.o
 lib-$(CONFIG_UNCOMPRESS)                += decompress_uncompress.o
 lib-$(CONFIG_UNZIP)                     += $(GUNZIP_FILES)
 lib-$(CONFIG_FEATURE_COMPRESS_USAGE)    += decompress_bunzip2.o
-

archival/libunarchive/get_header_tar_bz2.c

@@ -11,7 +11,7 @@ char get_header_tar_bz2(archive_handle_t *archive_handle)
 	/* Can't lseek over pipes */
 	archive_handle->seek = seek_by_read;
 
-	archive_handle->src_fd = open_transformer(archive_handle->src_fd, unpack_bz2_stream);
+	archive_handle->src_fd = open_transformer(archive_handle->src_fd, unpack_bz2_stream, "bunzip2", "bunzip2", "-cf", "-", NULL);
 	archive_handle->offset = 0;
 	while (get_header_tar(archive_handle) == EXIT_SUCCESS) /**/;
 

archival/libunarchive/get_header_tar_gz.c

@@ -8,19 +8,26 @@
 
 char get_header_tar_gz(archive_handle_t *archive_handle)
 {
+#if BB_MMU
 	unsigned char magic[2];
+#endif
 
 	/* Can't lseek over pipes */
 	archive_handle->seek = seek_by_read;
 
+	/* Check gzip magic only if open_transformer will invoke unpack_gz_stream (MMU case).
+	 * Otherwise, it will invoke an external helper "gunzip -cf" (NOMMU case) which will
+	 * need the header. */
+#if BB_MMU
 	xread(archive_handle->src_fd, &magic, 2);
 	if ((magic[0] != 0x1f) || (magic[1] != 0x8b)) {
 		bb_error_msg_and_die("invalid gzip magic");
 	}
 
 	check_header_gzip_or_die(archive_handle->src_fd);
+#endif
 
-	archive_handle->src_fd = open_transformer(archive_handle->src_fd, unpack_gz_stream);
+	archive_handle->src_fd = open_transformer(archive_handle->src_fd, unpack_gz_stream, "gunzip", "gunzip", "-cf", "-", NULL);
 	archive_handle->offset = 0;
 	while (get_header_tar(archive_handle) == EXIT_SUCCESS) /**/;
 

archival/libunarchive/get_header_tar_lzma.c

@@ -14,7 +14,7 @@ char get_header_tar_lzma(archive_handle_t * archive_handle)
 	/* Can't lseek over pipes */
 	archive_handle->seek = seek_by_read;
 
-	archive_handle->src_fd = open_transformer(archive_handle->src_fd, unpack_lzma_stream);
+	archive_handle->src_fd = open_transformer(archive_handle->src_fd, unpack_lzma_stream, "unlzma", "unlzma", "-cf", "-", NULL);
 	archive_handle->offset = 0;
 	while (get_header_tar(archive_handle) == EXIT_SUCCESS) /**/;
 

archival/libunarchive/open_transformer.c

@@ -7,29 +7,48 @@
 #include "unarchive.h"
 
 /* transformer(), more than meets the eye */
+/*
+ * On MMU machine, the transform_prog and ... are stripped
+ * by a macro in include/unarchive.h. On NOMMU, transformer is stripped.
+ */
 int open_transformer(int src_fd,
-	USE_DESKTOP(long long) int (*transformer)(int src_fd, int dst_fd))
+	USE_DESKTOP(long long) int (*transformer)(int src_fd, int dst_fd),
+	const char *transform_prog, ...)
 {
 	int fd_pipe[2];
 	int pid;
 
 	xpipe(fd_pipe);
 
+#if BB_MMU
 	pid = fork();
-	if (pid == -1) {
+#else
+	pid = vfork();
+#endif
+	if (pid == -1)
 		bb_perror_msg_and_die("fork failed");
-	}
 
 	if (pid == 0) {
+#if !BB_MMU
+		va_list ap;
+#endif
 		/* child process */
 		close(fd_pipe[0]); /* We don't wan't to read from the parent */
 		// FIXME: error check?
+#if BB_MMU
 		transformer(src_fd, fd_pipe[1]);
 		if (ENABLE_FEATURE_CLEAN_UP) {
 			close(fd_pipe[1]); /* Send EOF */
 			close(src_fd);
 		}
 		exit(0);
+#else
+		xmove_fd(src_fd, 0);
+		xmove_fd(fd_pipe[1], 1);
+		va_start(ap, transform_prog);
+		BB_EXECVP(transform_prog, ap);
+		bb_perror_and_die("exec failed");
+#endif
 		/* notreached */
 	}
 

archival/rpm.c

@@ -187,9 +187,15 @@ int rpm_main(int argc, char **argv)
 
 static void extract_cpio_gz(int fd)
 {
-	USE_DESKTOP(long long) int (*xformer)(int src_fd, int dst_fd);
 	archive_handle_t *archive_handle;
 	unsigned char magic[2];
+#if BB_MMU
+	USE_DESKTOP(long long) int (*xformer)(int src_fd, int dst_fd);
+	enum { xformer_prog = 0 };
+#else
+	enum { xformer = 0 };
+	const char *xformer_prog;
+#endif
 
 	/* Initialize */
 	archive_handle = init_handle();
@@ -202,11 +208,19 @@ static void extract_cpio_gz(int fd)
 	archive_handle->offset = 0;
 
 	xread(archive_handle->src_fd, &magic, 2);
+#if BB_MMU
 	xformer = unpack_gz_stream;
+#else
+	xformer_prog = "gunzip";
+#endif
 	if ((magic[0] != 0x1f) || (magic[1] != 0x8b)) {
 		if (ENABLE_FEATURE_RPM_BZ2
 		 && (magic[0] == 0x42) && (magic[1] == 0x5a)) {
+#if BB_MMU
 			xformer = unpack_bz2_stream;
+#else
+			xformer_prog = "bunzip2";
+#endif
 	/* We can do better, need modifying unpack_bz2_stream to not require
 	 * first 2 bytes. Not very hard to do... I mean, TODO :) */
 			xlseek(archive_handle->src_fd, -2, SEEK_CUR);
@@ -214,11 +228,17 @@ static void extract_cpio_gz(int fd)
 			bb_error_msg_and_die("no gzip"
 				USE_FEATURE_RPM_BZ2("/bzip")
 				" magic");
-	} else
+	} else {
 		check_header_gzip_or_die(archive_handle->src_fd);
+#if !BB_MMU
+		/* NOMMU version of open_transformer execs an external unzipper that should
+		 * have the file position at the start of the file */
+		xlseek(archive_handle->src_fd, 0, SEEK_SET);
+#endif
+	}
 
 	xchdir("/"); /* Install RPM's to root */
-	archive_handle->src_fd = open_transformer(archive_handle->src_fd, xformer);
+	archive_handle->src_fd = open_transformer(archive_handle->src_fd, xformer, xformer_prog, xformer_prog, "-cf", "-", NULL);
 	archive_handle->offset = 0;
 	while (get_header_cpio(archive_handle) == EXIT_SUCCESS)
 		continue;

archival/tar.c

@@ -660,7 +660,7 @@ static char get_header_tar_Z(archive_handle_t *archive_handle)
 		bb_error_msg_and_die("invalid magic");
 	}
 
-	archive_handle->src_fd = open_transformer(archive_handle->src_fd, uncompress);
+	archive_handle->src_fd = open_transformer(archive_handle->src_fd, uncompress, "uncompress", "uncompress", "-cf", "-", NULL);
 	archive_handle->offset = 0;
 	while (get_header_tar(archive_handle) == EXIT_SUCCESS)
 		/* nothing */;

include/unarchive.h

@@ -115,7 +115,13 @@ extern USE_DESKTOP(long long) int inflate_unzip(inflate_unzip_result *res, unsig
 extern USE_DESKTOP(long long) int unpack_gz_stream(int src_fd, int dst_fd);
 extern USE_DESKTOP(long long) int unpack_lzma_stream(int src_fd, int dst_fd);
 
+#if BB_MMU
 extern int open_transformer(int src_fd,
 	USE_DESKTOP(long long) int (*transformer)(int src_fd, int dst_fd));
+#define open_transformer(src_fd, transformer, transform_prog, ...) open_transformer(src_fd, transformer)
+#else
+extern int open_transformer(int src_fd, const char *transform_prog, ...);
+#define open_transformer(src_fd, transformer, transform_prog, ...) open_transformer(src_fd, transform_prog, __VA_ARGS__)
+#endif
 
 #endif