open_transformer: do not duplicate "<program> -cf -"

   text    data     bss     dec     hex filename
 677858     738    7236  685832   a7708 busybox_old
 677804     738    7236  685778   a76d2 busybox_unstripped

7 files changed, 22 insertions, 20 deletions

diff --git a/archival/libunarchive/get_header_tar_bz2.c b/archival/libunarchive/get_header_tar_bz2.c
index 6d4f5851e..c2cbaff5f 100644
--- a/archival/libunarchive/get_header_tar_bz2.c
+++ b/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, "bunzip2", "bunzip2", "-cf", "-", NULL);
+        archive_handle->src_fd = open_transformer(archive_handle->src_fd, unpack_bz2_stream, "bunzip2");
         archive_handle->offset = 0;
         while (get_header_tar(archive_handle) == EXIT_SUCCESS)
                 continue;
diff --git a/archival/libunarchive/get_header_tar_gz.c b/archival/libunarchive/get_header_tar_gz.c
index dd655f557..9772e33fb 100644
--- a/archival/libunarchive/get_header_tar_gz.c
+++ b/archival/libunarchive/get_header_tar_gz.c
@@ -25,7 +25,7 @@ char get_header_tar_gz(archive_handle_t *archive_handle)
         }
 #endif
 
-        archive_handle->src_fd = open_transformer(archive_handle->src_fd, unpack_gz_stream, "gunzip", "gunzip", "-cf", "-", NULL);
+        archive_handle->src_fd = open_transformer(archive_handle->src_fd, unpack_gz_stream, "gunzip");
         archive_handle->offset = 0;
         while (get_header_tar(archive_handle) == EXIT_SUCCESS)
                 continue;
diff --git a/archival/libunarchive/get_header_tar_lzma.c b/archival/libunarchive/get_header_tar_lzma.c
index cf73824e3..c859dcc58 100644
--- a/archival/libunarchive/get_header_tar_lzma.c
+++ b/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, "unlzma", "unlzma", "-cf", "-", NULL);
+        archive_handle->src_fd = open_transformer(archive_handle->src_fd, unpack_lzma_stream, "unlzma");
         archive_handle->offset = 0;
         while (get_header_tar(archive_handle) == EXIT_SUCCESS)
                 continue;
diff --git a/archival/libunarchive/open_transformer.c b/archival/libunarchive/open_transformer.c
index 355613a67..757a2a389 100644
--- a/archival/libunarchive/open_transformer.c
+++ b/archival/libunarchive/open_transformer.c
@@ -8,12 +8,12 @@
 
 /* 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.
+ * On MMU machine, the transform_prog is removed by macro magic
+ * in include/unarchive.h. On NOMMU, transformer is removed.
  */
 int open_transformer(int src_fd,
         USE_DESKTOP(long long) int (*transformer)(int src_fd, int dst_fd),
-        const char *transform_prog, ...)
+        const char *transform_prog)
 {
         int fd_pipe[2];
         int pid;
@@ -29,9 +29,6 @@ int open_transformer(int src_fd,
                 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?
@@ -43,12 +40,17 @@ int open_transformer(int src_fd,
                 }
                 exit(0);
 #else
-                xmove_fd(src_fd, 0);
-                xmove_fd(fd_pipe[1], 1);
-                va_start(ap, transform_prog);
-                /* hoping that va_list -> char** on our CPU is working... */
-                BB_EXECVP(transform_prog, (void*)ap);
-                bb_perror_msg_and_die("exec failed");
+                {
+                        char *argv[4];
+                        xmove_fd(src_fd, 0);
+                        xmove_fd(fd_pipe[1], 1);
+                        argv[0] = (char*)transform_prog;
+                        argv[1] = (char*)"-cf";
+                        argv[2] = (char*)"-";
+                        argv[3] = NULL;
+                        BB_EXECVP(transform_prog, argv);
+                        bb_perror_msg_and_die("exec failed");
+                }
 #endif
                 /* notreached */
         }
diff --git a/archival/rpm.c b/archival/rpm.c
index f078aea10..41b8c81b2 100644
--- a/archival/rpm.c
+++ b/archival/rpm.c
@@ -237,7 +237,7 @@ static void extract_cpio_gz(int fd)
         }
 
         xchdir("/"); /* Install RPM's to root */
-        archive_handle->src_fd = open_transformer(archive_handle->src_fd, xformer, xformer_prog, xformer_prog, "-cf", "-", NULL);
+        archive_handle->src_fd = open_transformer(archive_handle->src_fd, xformer, xformer_prog);
         archive_handle->offset = 0;
         while (get_header_cpio(archive_handle) == EXIT_SUCCESS)
                 continue;
diff --git a/archival/tar.c b/archival/tar.c
index 3fe188656..1def615b5 100644
--- a/archival/tar.c
+++ b/archival/tar.c
@@ -662,7 +662,7 @@ 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, "uncompress", "uncompress", "-cf", "-", NULL);
+        archive_handle->src_fd = open_transformer(archive_handle->src_fd, uncompress, "uncompress");
         archive_handle->offset = 0;
         while (get_header_tar(archive_handle) == EXIT_SUCCESS)
                 continue;
diff --git a/include/unarchive.h b/include/unarchive.h
index 3d3965528..00a00d672 100644
--- a/include/unarchive.h
+++ b/include/unarchive.h
@@ -116,10 +116,10 @@ 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)
+#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__)
+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)
 #endif
 
 #endif