open_transformer: do not return fd, it does not change

libbb: adopt zipped read from modprobe-small

function                                             old     new   delta
getoptscmd                                           708     713      +5
qgravechar                                           106     109      +3
huft_build                                          1165    1168      +3
tr_main                                              474     472      -2
open_transformer                                      91      89      -2
evalvar                                             1376    1374      -2
rpm_main                                            1691    1688      -3
qrealloc                                              36      33      -3
get_header_tar_lzma                                   55      52      -3
get_header_tar_gz                                    100      97      -3
get_header_tar_bz2                                    55      52      -3
get_header_tar_Z                                      89      86      -3
find_main                                            418     406     -12
prepare                                              302     283     -19
xmalloc_open_zipped_read_close                       161     135     -26
xmalloc_read                                         248     199     -49
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 3/13 up/down: 11/-130)         Total: -119 bytes

11 files changed, 70 insertions, 66 deletions

diff --git a/archival/libunarchive/Kbuild b/archival/libunarchive/Kbuild
index 1bc054a96..609bc50cb 100644
--- a/archival/libunarchive/Kbuild
+++ b/archival/libunarchive/Kbuild
@@ -43,6 +43,8 @@ lib-$(CONFIG_FEATURE_DEB_TAR_GZ)        += open_transformer.o
 lib-$(CONFIG_FEATURE_DEB_TAR_BZ2)       += open_transformer.o
 lib-$(CONFIG_FEATURE_DEB_TAR_LZMA)      += open_transformer.o
 
+lib-$(CONFIG_FEATURE_MODPROBE_SMALL_ZIPPED) += open_transformer.o decompress_unzip.o decompress_bunzip2.o
+
 lib-$(CONFIG_AR)                        += get_header_ar.o unpack_ar_archive.o
 lib-$(CONFIG_BUNZIP2)                   += decompress_bunzip2.o
 lib-$(CONFIG_UNLZMA)                    += decompress_unlzma.o
diff --git a/archival/libunarchive/get_header_tar_bz2.c b/archival/libunarchive/get_header_tar_bz2.c
index cfdc016d6..035c10bfb 100644
--- a/archival/libunarchive/get_header_tar_bz2.c
+++ b/archival/libunarchive/get_header_tar_bz2.c
@@ -11,7 +11,7 @@ char FAST_FUNC 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");
+        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 33c62729e..086c6df42 100644
--- a/archival/libunarchive/get_header_tar_gz.c
+++ b/archival/libunarchive/get_header_tar_gz.c
@@ -25,7 +25,7 @@ char FAST_FUNC get_header_tar_gz(archive_handle_t *archive_handle)
         }
 #endif
 
-        archive_handle->src_fd = open_transformer(archive_handle->src_fd, unpack_gz_stream, "gunzip");
+        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 730c1b1bb..03b1b792d 100644
--- a/archival/libunarchive/get_header_tar_lzma.c
+++ b/archival/libunarchive/get_header_tar_lzma.c
@@ -14,7 +14,7 @@ char FAST_FUNC 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");
+        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 a5ee97167..42fdd96a6 100644
--- a/archival/libunarchive/open_transformer.c
+++ b/archival/libunarchive/open_transformer.c
@@ -11,7 +11,7 @@
  * On MMU machine, the transform_prog is removed by macro magic
  * in include/unarchive.h. On NOMMU, transformer is removed.
  */
-int FAST_FUNC open_transformer(int src_fd,
+void FAST_FUNC open_transformer(int fd,
         USE_DESKTOP(long long) int FAST_FUNC (*transformer)(int src_fd, int dst_fd),
         const char *transform_prog)
 {
@@ -32,20 +32,20 @@ int FAST_FUNC open_transformer(int src_fd,
 
         if (pid == 0) {
                 /* child process */
-                close(fd_pipe.rd); /* We don't want to read from the parent */
+                close(fd_pipe.rd); /* we don't want to read from the parent */
                 // FIXME: error check?
 #if BB_MMU
-                transformer(src_fd, fd_pipe.wr);
+                transformer(fd, fd_pipe.wr);
                 if (ENABLE_FEATURE_CLEAN_UP) {
-                        close(fd_pipe.wr); /* Send EOF */
-                        close(src_fd);
+                        close(fd_pipe.wr); /* send EOF */
+                        close(fd);
                 }
                 /* must be _exit! bug was actually seen here */
                 _exit(EXIT_SUCCESS);
 #else
                 {
                         char *argv[4];
-                        xmove_fd(src_fd, 0);
+                        xmove_fd(fd, 0);
                         xmove_fd(fd_pipe.wr, 1);
                         argv[0] = (char*)transform_prog;
                         argv[1] = (char*)"-cf";
@@ -59,9 +59,6 @@ int FAST_FUNC open_transformer(int src_fd,
         }
 
         /* parent process */
-        close(fd_pipe.wr); /* Don't want to write to the child */
-
-//TODO: get rid of return value (become void)?
-        xmove_fd(fd_pipe.rd, src_fd);
-        return src_fd;
+        close(fd_pipe.wr); /* don't want to write to the child */
+        xmove_fd(fd_pipe.rd, fd);
 }
diff --git a/archival/rpm.c b/archival/rpm.c
index b3d7cd5f7..e6dd3d853 100644
--- a/archival/rpm.c
+++ b/archival/rpm.c
@@ -236,7 +236,7 @@ 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);
+        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 13cdbd930..a46442f8e 100644
--- a/archival/tar.c
+++ b/archival/tar.c
@@ -692,7 +692,7 @@ static char FAST_FUNC 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");
+        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/libbb.h b/include/libbb.h
index 2dfdded5b..671584b43 100644
--- a/include/libbb.h
+++ b/include/libbb.h
@@ -583,15 +583,18 @@ extern unsigned char xread_char(int fd) FAST_FUNC;
 // Reads one line a-la fgets (but doesn't save terminating '\n').
 // Uses single full_read() call, works only on seekable streams.
 extern char *reads(int fd, char *buf, size_t count) FAST_FUNC;
+extern ssize_t read_close(int fd, void *buf, size_t maxsz) FAST_FUNC;
+extern ssize_t open_read_close(const char *filename, void *buf, size_t maxsz) FAST_FUNC;
 // Reads one line a-la fgets (but doesn't save terminating '\n').
 // Reads byte-by-byte. Useful when it is important to not read ahead.
 // Bytes are appended to pfx (which must be malloced, or NULL).
 extern char *xmalloc_reads(int fd, char *pfx, size_t *maxsz_p) FAST_FUNC;
-extern ssize_t read_close(int fd, void *buf, size_t maxsz) FAST_FUNC;
-extern ssize_t open_read_close(const char *filename, void *buf, size_t maxsz) FAST_FUNC;
-extern void *xmalloc_read(int fd, size_t *sizep) FAST_FUNC;
+/* Reads block up to *maxsz_p (default: MAX_INT(ssize_t)) */
+extern void *xmalloc_read(int fd, size_t *maxsz_p) FAST_FUNC;
 /* Returns NULL if file can't be opened */
 extern void *xmalloc_open_read_close(const char *filename, size_t *maxsz_p) FAST_FUNC;
+/* Autodetects .gz etc */
+extern void *xmalloc_open_zipped_read_close(const char *fname, size_t *maxsz_p) FAST_FUNC;
 /* Never returns NULL */
 extern void *xmalloc_xopen_read_close(const char *filename, size_t *maxsz_p) FAST_FUNC;
 
diff --git a/include/unarchive.h b/include/unarchive.h
index 1fab570c3..0e380db08 100644
--- a/include/unarchive.h
+++ b/include/unarchive.h
@@ -126,12 +126,12 @@ extern USE_DESKTOP(long long) int unpack_gz_stream(int src_fd, int dst_fd) FAST_
 extern USE_DESKTOP(long long) int unpack_lzma_stream(int src_fd, int dst_fd) FAST_FUNC;
 
 #if BB_MMU
-extern int open_transformer(int src_fd,
+extern void open_transformer(int fd,
         USE_DESKTOP(long long) int FAST_FUNC (*transformer)(int src_fd, int dst_fd)) FAST_FUNC;
-#define open_transformer(src_fd, transformer, transform_prog) open_transformer(src_fd, transformer)
+#define open_transformer(fd, transformer, transform_prog) open_transformer(fd, transformer)
 #else
 extern int open_transformer(int src_fd, const char *transform_prog) FAST_FUNC;
-#define open_transformer(src_fd, transformer, transform_prog) open_transformer(src_fd, transform_prog)
+#define open_transformer(fd, transformer, transform_prog) open_transformer(fd, transform_prog)
 #endif
 
 #if __GNUC_PREREQ(4,1)
diff --git a/libbb/read.c b/libbb/read.c
index e67bbfb7e..7af895207 100644
--- a/libbb/read.c
+++ b/libbb/read.c
@@ -8,6 +8,9 @@
  */
 
 #include "libbb.h"
+#if ENABLE_FEATURE_MODPROBE_SMALL_ZIPPED
+#include "unarchive.h"
+#endif
 
 ssize_t FAST_FUNC safe_read(int fd, void *buf, size_t count)
 {
@@ -206,14 +209,14 @@ ssize_t FAST_FUNC open_read_close(const char *filename, void *buf, size_t size)
 
 // Read (potentially big) files in one go. File size is estimated
 // by stat. Extra '\0' byte is appended.
-void* FAST_FUNC xmalloc_read(int fd, size_t *sizep)
+void* FAST_FUNC xmalloc_read(int fd, size_t *maxsz_p)
 {
         char *buf;
         size_t size, rd_size, total;
-        off_t to_read;
+        size_t to_read;
         struct stat st;
 
-        to_read = sizep ? *sizep : MAXINT(ssize_t); /* max to read */
+        to_read = maxsz_p ? *maxsz_p : MAXINT(ssize_t); /* max to read */
 
         /* Estimate file size */
         st.st_size = 0; /* in case fstat fails, assume 0 */
@@ -229,16 +232,16 @@ void* FAST_FUNC xmalloc_read(int fd, size_t *sizep)
                         size = to_read;
                 buf = xrealloc(buf, total + size + 1);
                 rd_size = full_read(fd, buf + total, size);
-                if ((ssize_t)rd_size < 0) { /* error */
+                if ((ssize_t)rd_size == (ssize_t)(-1)) { /* error */
                         free(buf);
                         return NULL;
                 }
                 total += rd_size;
                 if (rd_size < size) /* EOF */
                         break;
-                to_read -= rd_size;
-                if (to_read <= 0)
+                if (to_read <= rd_size)
                         break;
+                to_read -= rd_size;
                 /* grow by 1/8, but in [1k..64k] bounds */
                 size = ((total / 8) | 0x3ff) + 1;
                 if (size > 64*1024)
@@ -247,8 +250,8 @@ void* FAST_FUNC xmalloc_read(int fd, size_t *sizep)
         xrealloc(buf, total + 1);
         buf[total] = '\0';
 
-        if (sizep)
-                *sizep = total;
+        if (maxsz_p)
+                *maxsz_p = total;
         return buf;
 }
 
@@ -260,7 +263,7 @@ void* FAST_FUNC xmalloc_read(int fd, size_t *sizep)
 
 // Read (potentially big) files in one go. File size is estimated by
 // lseek to end.
-void* FAST_FUNC xmalloc_open_read_close(const char *filename, size_t *sizep)
+void* FAST_FUNC xmalloc_open_read_close(const char *filename, size_t *maxsz_p)
 {
         char *buf;
         size_t size;
@@ -277,7 +280,7 @@ void* FAST_FUNC xmalloc_open_read_close(const char *filename, size_t *sizep)
         len = lseek(fd, 0, SEEK_END) | 0x3ff; /* + up to 1k */
         if (len != (off_t)-1) {
                 xlseek(fd, 0, SEEK_SET);
-                size = sizep ? *sizep : INT_MAX;
+                size = maxsz_p ? *maxsz_p : INT_MAX;
                 if (len < size)
                         size = len;
         }
@@ -291,15 +294,15 @@ void* FAST_FUNC xmalloc_open_read_close(const char *filename, size_t *sizep)
         xrealloc(buf, size + 1);
         buf[size] = '\0';
 
-        if (sizep)
-                *sizep = size;
+        if (maxsz_p)
+                *maxsz_p = size;
         return buf;
 }
 #endif
 
 // Read (potentially big) files in one go. File size is estimated
 // by stat.
-void* FAST_FUNC xmalloc_open_read_close(const char *filename, size_t *sizep)
+void* FAST_FUNC xmalloc_open_read_close(const char *filename, size_t *maxsz_p)
 {
         char *buf;
         int fd;
@@ -308,15 +311,42 @@ void* FAST_FUNC xmalloc_open_read_close(const char *filename, size_t *sizep)
         if (fd < 0)
                 return NULL;
 
-        buf = xmalloc_read(fd, sizep);
+        buf = xmalloc_read(fd, maxsz_p);
         close(fd);
         return buf;
 }
 
-void* FAST_FUNC xmalloc_xopen_read_close(const char *filename, size_t *sizep)
+void* FAST_FUNC xmalloc_xopen_read_close(const char *filename, size_t *maxsz_p)
 {
-        void *buf = xmalloc_open_read_close(filename, sizep);
+        void *buf = xmalloc_open_read_close(filename, maxsz_p);
         if (!buf)
                 bb_perror_msg_and_die("can't read '%s'", filename);
         return buf;
 }
+
+#if ENABLE_FEATURE_MODPROBE_SMALL_ZIPPED
+void* FAST_FUNC xmalloc_open_zipped_read_close(const char *fname, size_t *maxsz_p)
+{
+        char *image;
+        char *suffix;
+
+        int fd = open(fname, O_RDONLY);
+        if (fd < 0)
+                return NULL;
+
+        suffix = strrchr(fname, '.');
+        if (suffix) {
+                if (strcmp(suffix, ".gz") == 0)
+                        open_transformer(fd, unpack_gz_stream, "gunzip");
+                else if (strcmp(suffix, ".bz2") == 0)
+                        open_transformer(fd, unpack_bz2_stream, "bunzip2");
+        }
+
+        image = xmalloc_read(fd, maxsz_p);
+        if (!image)
+                bb_perror_msg("read error from '%s'", fname);
+        close(fd);
+
+        return image;
+}
+#endif
diff --git a/modutils/modprobe-small.c b/modutils/modprobe-small.c
index f28c42558..517c103d5 100644
--- a/modutils/modprobe-small.c
+++ b/modutils/modprobe-small.c
@@ -143,34 +143,6 @@ static char* str_2_list(const char *str)
 }
 
 #if ENABLE_FEATURE_MODPROBE_SMALL_ZIPPED
-static char *xmalloc_open_zipped_read_close(const char *fname, size_t *sizep)
-{
-        size_t len;
-        char *image;
-        char *suffix;
-
-        int fd = open_or_warn(fname, O_RDONLY);
-        if (fd < 0)
-                return NULL;
-
-        suffix = strrchr(fname, '.');
-        if (suffix) {
-                if (strcmp(suffix, ".gz") == 0)
-                        fd = open_transformer(fd, unpack_gz_stream, "gunzip");
-                else if (strcmp(suffix, ".bz2") == 0)
-                        fd = open_transformer(fd, unpack_bz2_stream, "bunzip2");
-        }
-
-        len = (sizep) ? *sizep : 64 * 1024 * 1024;
-        image = xmalloc_read(fd, &len);
-        if (!image)
-                bb_perror_msg("read error from '%s'", fname);
-        close(fd);
-
-        if (sizep)
-                *sizep = len;
-        return image;
-}
 # define read_module xmalloc_open_zipped_read_close
 #else
 # define read_module xmalloc_open_read_close