Re: [Libguestfs] [PATCH 2/2] filearch: support gzip/xz-compressed files

Extract them to find out the architecture of the data they hold. Useful to detect the architecture of e.g. compressed Linux modules. --- src/filearch.c | 64 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 64 insertions(+) diff --git a/src/filearch.c b/src/filearch.c index 219eaae..df65c98 100644 --- a/src/filearch.c +++ b/src/filearch.c @@ -250,6 +250,66 @@ cpio_arch (guestfs_h *g, const char *file, const char *path) return ret; } +static char * +compressed_file_arch (guestfs_h *g, const char *path, const char *method) +{ + CLEANUP_FREE char *tmpdir = guestfs_get_tmpdir (g), *dir = NULL; + CLEANUP_FREE char *tempfile = NULL, *tempfile_extracted = NULL; + CLEANUP_CMD_CLOSE struct command *cmd = guestfs_int_new_command (g); + char *ret = NULL; + int64_t size; + int r; + bool matched; + + if (asprintf (&dir, "%s/libguestfsXXXXXX", tmpdir) == -1) { + perrorf (g, "asprintf"); + return NULL; + } + + /* Security: Refuse to download file if it is huge. */ + size = guestfs_filesize (g, path); + if (size == -1 || size > 10000000) { + error (g, _("size of %s unreasonable (%" PRIi64 " bytes)"), + path, size); + goto out; + } + + if (mkdtemp (dir) == NULL) { + perrorf (g, "mkdtemp"); + goto out; + } + + tempfile = safe_asprintf (g, "%s/file", dir); + if (guestfs_download (g, path, tempfile) == -1) + goto out; + + tempfile_extracted = safe_asprintf (g, "%s/file_extracted", dir); + + /* Construct a command to extract named binaries from the initrd file. */ + guestfs_int_cmd_add_string_unquoted (cmd, method); + guestfs_int_cmd_add_string_unquoted (cmd, " "); + guestfs_int_cmd_add_string_quoted (cmd, tempfile); + guestfs_int_cmd_add_string_unquoted (cmd, " > "); + guestfs_int_cmd_add_string_quoted (cmd, tempfile_extracted); + + r = guestfs_int_cmd_run (cmd); + if (r == -1) + goto out; + if (!WIFEXITED (r) || WEXITSTATUS (r) != 0) { + guestfs_int_external_command_failed (g, r, method, path); + goto out; + } + + ret = magic_for_file (g, tempfile_extracted, NULL, &matched); + if (!matched) + error (g, "file_architecture: could not determine architecture of compressed file"); + + out: + guestfs_int_recursive_remove_dir (g, dir); + + return ret; +} + char * guestfs_impl_file_architecture (guestfs_h *g, const char *path) { @@ -272,6 +332,10 @@ guestfs_impl_file_architecture (guestfs_h *g, const char *path) ret = safe_strdup (g, "x86_64"); else if (strstr (file, "cpio archive")) ret = cpio_arch (g, file, path); + else if (strstr (file, "gzip compressed data")) + ret = compressed_file_arch (g, path, "zcat"); + else if (strstr (file, "XZ compressed data")) + ret = compressed_file_arch (g, path, "xzcat"); else error (g, "file_architecture: unknown architecture: %s", path);