less: document -S flag and make it independently configurable
[oweals/busybox.git] / archival / libarchive / open_transformer.c
index 27854af21e36287ad941cbf9783becd5705e9937..be536a3d7e715f41ef0e1aacd30842092844dc7e 100644 (file)
@@ -6,19 +6,19 @@
 #include "libbb.h"
 #include "bb_archive.h"
 
-void FAST_FUNC init_transformer_aux_data(transformer_aux_data_t *aux)
+void FAST_FUNC init_transformer_state(transformer_state_t *xstate)
 {
-       memset(aux, 0, sizeof(*aux));
+       memset(xstate, 0, sizeof(*xstate));
 }
 
-int FAST_FUNC check_signature16(transformer_aux_data_t *aux, int src_fd, unsigned magic16)
+int FAST_FUNC check_signature16(transformer_state_t *xstate, unsigned magic16)
 {
-       if (aux && aux->check_signature) {
+       if (xstate->check_signature) {
                uint16_t magic2;
-               if (full_read(src_fd, &magic2, 2) != 2 || magic2 != magic16) {
+               if (full_read(xstate->src_fd, &magic2, 2) != 2 || magic2 != magic16) {
                        bb_error_msg("invalid magic");
 #if 0 /* possible future extension */
-                       if (aux->check_signature > 1)
+                       if (xstate->check_signature > 1)
                                xfunc_die();
 #endif
                        return -1;
@@ -27,6 +27,47 @@ int FAST_FUNC check_signature16(transformer_aux_data_t *aux, int src_fd, unsigne
        return 0;
 }
 
+ssize_t FAST_FUNC transformer_write(transformer_state_t *xstate, const void *buf, size_t bufsize)
+{
+       ssize_t nwrote;
+
+       if (xstate->mem_output_size_max != 0) {
+               size_t pos = xstate->mem_output_size;
+               size_t size;
+
+               size = (xstate->mem_output_size += bufsize);
+               if (size > xstate->mem_output_size_max) {
+                       free(xstate->mem_output_buf);
+                       xstate->mem_output_buf = NULL;
+                       bb_perror_msg("buffer %u too small", (unsigned)xstate->mem_output_size_max);
+                       nwrote = -1;
+                       goto ret;
+               }
+               xstate->mem_output_buf = xrealloc(xstate->mem_output_buf, size + 1);
+               memcpy(xstate->mem_output_buf + pos, buf, bufsize);
+               xstate->mem_output_buf[size] = '\0';
+               nwrote = bufsize;
+       } else {
+               nwrote = full_write(xstate->dst_fd, buf, bufsize);
+               if (nwrote != (ssize_t)bufsize) {
+                       bb_perror_msg("write");
+                       nwrote = -1;
+                       goto ret;
+               }
+       }
+ ret:
+       return nwrote;
+}
+
+ssize_t FAST_FUNC xtransformer_write(transformer_state_t *xstate, const void *buf, size_t bufsize)
+{
+       ssize_t nwrote = transformer_write(xstate, buf, bufsize);
+       if (nwrote != (ssize_t)bufsize) {
+               xfunc_die();
+       }
+       return nwrote;
+}
+
 void check_errors_in_children(int signo)
 {
        int status;
@@ -60,12 +101,12 @@ void check_errors_in_children(int signo)
 
 /* transformer(), more than meets the eye */
 #if BB_MMU
-void FAST_FUNC open_transformer(int fd,
+void FAST_FUNC fork_transformer(int fd,
        int check_signature,
-       IF_DESKTOP(long long) int FAST_FUNC (*transformer)(transformer_aux_data_t *aux, int src_fd, int dst_fd)
+       IF_DESKTOP(long long) int FAST_FUNC (*transformer)(transformer_state_t *xstate)
 )
 #else
-void FAST_FUNC open_transformer(int fd, const char *transform_prog)
+void FAST_FUNC fork_transformer(int fd, const char *transform_prog)
 #endif
 {
        struct fd_pair fd_pipe;
@@ -80,10 +121,12 @@ void FAST_FUNC open_transformer(int fd, const char *transform_prog)
 #if BB_MMU
                {
                        IF_DESKTOP(long long) int r;
-                       transformer_aux_data_t aux;
-                       init_transformer_aux_data(&aux);
-                       aux.check_signature = check_signature;
-                       r = transformer(&aux, fd, fd_pipe.wr);
+                       transformer_state_t xstate;
+                       init_transformer_state(&xstate);
+                       xstate.check_signature = check_signature;
+                       xstate.src_fd = fd;
+                       xstate.dst_fd = fd_pipe.wr;
+                       r = transformer(&xstate);
                        if (ENABLE_FEATURE_CLEAN_UP) {
                                close(fd_pipe.wr); /* send EOF */
                                close(fd);
@@ -118,16 +161,19 @@ void FAST_FUNC open_transformer(int fd, const char *transform_prog)
 /* Used by e.g. rpm which gives us a fd without filename,
  * thus we can't guess the format from filename's extension.
  */
-int FAST_FUNC setup_unzip_on_fd(int fd, int fail_if_not_detected)
+static transformer_state_t *setup_transformer_on_fd(int fd, int fail_if_not_compressed)
 {
        union {
                uint8_t b[4];
                uint16_t b16[2];
                uint32_t b32[1];
        } magic;
-       int offset = -2;
-       USE_FOR_MMU(IF_DESKTOP(long long) int FAST_FUNC (*xformer)(transformer_aux_data_t *aux, int src_fd, int dst_fd);)
-       USE_FOR_NOMMU(const char *xformer_prog;)
+       int offset;
+       transformer_state_t *xstate;
+
+       offset = -2;
+       xstate = xzalloc(sizeof(*xstate));
+       xstate->src_fd = fd;
 
        /* .gz and .bz2 both have 2-byte signature, and their
         * unpack_XXX_stream wants this header skipped. */
@@ -135,15 +181,22 @@ int FAST_FUNC setup_unzip_on_fd(int fd, int fail_if_not_detected)
        if (ENABLE_FEATURE_SEAMLESS_GZ
         && magic.b16[0] == GZIP_MAGIC
        ) {
-               USE_FOR_MMU(xformer = unpack_gz_stream;)
-               USE_FOR_NOMMU(xformer_prog = "gunzip";)
+               xstate->xformer = unpack_gz_stream;
+               USE_FOR_NOMMU(xstate->xformer_prog = "gunzip";)
+               goto found_magic;
+       }
+       if (ENABLE_FEATURE_SEAMLESS_Z
+        && magic.b16[0] == COMPRESS_MAGIC
+       ) {
+               xstate->xformer = unpack_Z_stream;
+               USE_FOR_NOMMU(xstate->xformer_prog = "uncompress";)
                goto found_magic;
        }
        if (ENABLE_FEATURE_SEAMLESS_BZ2
         && magic.b16[0] == BZIP2_MAGIC
        ) {
-               USE_FOR_MMU(xformer = unpack_bz2_stream;)
-               USE_FOR_NOMMU(xformer_prog = "bunzip2";)
+               xstate->xformer = unpack_bz2_stream;
+               USE_FOR_NOMMU(xstate->xformer_prog = "bunzip2";)
                goto found_magic;
        }
        if (ENABLE_FEATURE_SEAMLESS_XZ
@@ -152,77 +205,146 @@ int FAST_FUNC setup_unzip_on_fd(int fd, int fail_if_not_detected)
                offset = -6;
                xread(fd, magic.b32, sizeof(magic.b32[0]));
                if (magic.b32[0] == XZ_MAGIC2) {
-                       USE_FOR_MMU(xformer = unpack_xz_stream;)
-                       USE_FOR_NOMMU(xformer_prog = "unxz";)
+                       xstate->xformer = unpack_xz_stream;
+                       USE_FOR_NOMMU(xstate->xformer_prog = "unxz";)
                        goto found_magic;
                }
        }
 
        /* No known magic seen */
-       if (fail_if_not_detected)
+       if (fail_if_not_compressed)
                bb_error_msg_and_die("no gzip"
                        IF_FEATURE_SEAMLESS_BZ2("/bzip2")
                        IF_FEATURE_SEAMLESS_XZ("/xz")
                        " magic");
+
+       /* Some callers expect this function to "consume" fd
+        * even if data is not compressed. In this case,
+        * we return a state with trivial transformer.
+        */
+//     USE_FOR_MMU(xstate->xformer = copy_stream;)
+//     USE_FOR_NOMMU(xstate->xformer_prog = "cat";)
+       /* fall through to seeking bck over bytes we read earlier */
+
+ USE_FOR_NOMMU(found_magic:)
+       /* NOMMU version of fork_transformer execs
+        * an external unzipper that wants
+        * file position at the start of the file.
+        */
        xlseek(fd, offset, SEEK_CUR);
-       return 1;
 
- found_magic:
+ USE_FOR_MMU(found_magic:)
+       /* In MMU case, if magic was found, seeking back is not necessary */
+
+       return xstate;
+}
+
+/* Used by e.g. rpm which gives us a fd without filename,
+ * thus we can't guess the format from filename's extension.
+ */
+int FAST_FUNC setup_unzip_on_fd(int fd, int fail_if_not_compressed)
+{
+       transformer_state_t *xstate = setup_transformer_on_fd(fd, fail_if_not_compressed);
+
+       if (!xstate || !xstate->xformer) {
+               free(xstate);
+               return 1;
+       }
+
 # if BB_MMU
-       open_transformer_with_no_sig(fd, xformer);
+       fork_transformer_with_no_sig(xstate->src_fd, xstate->xformer);
 # else
-       /* NOMMU version of open_transformer execs
-        * an external unzipper that wants
-        * file position at the start of the file */
-       xlseek(fd, offset, SEEK_CUR);
-       open_transformer_with_sig(fd, xformer, xformer_prog);
+       fork_transformer_with_sig(xstate->src_fd, xstate->xformer, xstate->xformer_prog);
 # endif
+       free(xstate);
        return 0;
 }
 
-int FAST_FUNC open_zipped(const char *fname)
+static transformer_state_t *open_transformer(const char *fname, int fail_if_not_compressed)
 {
+       transformer_state_t *xstate;
        int fd;
 
        fd = open(fname, O_RDONLY);
        if (fd < 0)
-               return fd;
+               return NULL;
 
        if (ENABLE_FEATURE_SEAMLESS_LZMA) {
                /* .lzma has no header/signature, can only detect it by extension */
                char *sfx = strrchr(fname, '.');
                if (sfx && strcmp(sfx+1, "lzma") == 0) {
-                       open_transformer_with_sig(fd, unpack_lzma_stream, "unlzma");
-                       return fd;
+                       xstate = xzalloc(sizeof(*xstate));
+                       xstate->src_fd = fd;
+                       xstate->xformer = unpack_lzma_stream;
+                       USE_FOR_NOMMU(xstate->xformer_prog = "unlzma";)
+                       return xstate;
                }
        }
-       if ((ENABLE_FEATURE_SEAMLESS_GZ)
-        || (ENABLE_FEATURE_SEAMLESS_BZ2)
-        || (ENABLE_FEATURE_SEAMLESS_XZ)
-       ) {
-               /*
-                * Do we want to fail_if_not_detected?
-                * In most cases, no: think "insmod non_compressed_module".
-                * A case which would like to fail is "zcat uncompressed_file":
-                * otherwise, it happily outputs uncompressed_file as-is,
-                * which is, strictly speaking, not what is expected.
-                * If this ever becomes a problem, we can add
-                * fail_if_not_detected bool argument to open_zipped().
-                */
-               setup_unzip_on_fd(fd, /*fail_if_not_detected:*/ 0);
+
+       xstate = setup_transformer_on_fd(fd, fail_if_not_compressed);
+
+       return xstate;
+}
+
+int FAST_FUNC open_zipped(const char *fname, int fail_if_not_compressed)
+{
+       int fd;
+       transformer_state_t *xstate;
+
+       xstate = open_transformer(fname, fail_if_not_compressed);
+       if (!xstate)
+               return -1;
+
+       fd = xstate->src_fd;
+       if (xstate->xformer) {
+# if BB_MMU
+               fork_transformer_with_no_sig(xstate->src_fd, xstate->xformer);
+# else
+               fork_transformer_with_sig(xstate->src_fd, xstate->xformer, xstate->xformer_prog);
+# endif
        }
+       /* else: the file is not compressed */
 
+       free(xstate);
        return fd;
 }
 
-#endif /* SEAMLESS_COMPRESSION */
-
 void* FAST_FUNC xmalloc_open_zipped_read_close(const char *fname, size_t *maxsz_p)
 {
+# if 1
+       transformer_state_t *xstate;
+       char *image;
+
+       xstate = open_transformer(fname, /*fail_if_not_compressed:*/ 0);
+       if (!xstate) /* file open error */
+               return NULL;
+
+       image = NULL;
+       if (xstate->xformer) {
+               /* In-memory decompression */
+               xstate->mem_output_size_max = maxsz_p ? *maxsz_p : (size_t)(INT_MAX - 4095);
+               xstate->xformer(xstate);
+               if (xstate->mem_output_buf) {
+                       image = xstate->mem_output_buf;
+                       if (maxsz_p)
+                               *maxsz_p = xstate->mem_output_size;
+               }
+       } else {
+               /* File is not compressed */
+               image = xmalloc_read(xstate->src_fd, maxsz_p);
+       }
+
+       if (!image)
+               bb_perror_msg("read error from '%s'", fname);
+       close(xstate->src_fd);
+       free(xstate);
+       return image;
+# else
+       /* This version forks a subprocess - much more expensive */
        int fd;
        char *image;
 
-       fd = open_zipped(fname);
+       fd = open_zipped(fname, /*fail_if_not_compressed:*/ 0);
        if (fd < 0)
                return NULL;
 
@@ -230,6 +352,8 @@ void* FAST_FUNC xmalloc_open_zipped_read_close(const char *fname, size_t *maxsz_
        if (!image)
                bb_perror_msg("read error from '%s'", fname);
        close(fd);
-
        return image;
+# endif
 }
+
+#endif /* SEAMLESS_COMPRESSION */