New API: file-architecture

This change simply converts the existing Perl-only function
file_architecture into a core API call.  The core API call is
written in C and available in all languages and from guestfish.

3 files changed, 410 insertions, 1 deletions

diff --git a/src/Makefile.am b/src/Makefile.am
index 4135c8c9..61cec04e 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -126,11 +126,12 @@ libguestfs_la_SOURCES = \
 	gettext.h \
 	actions.c \
 	bindtests.c \
+	inspect.c \
 	launch.c \
 	proto.c \
 	libguestfs.syms
 
-libguestfs_la_LIBADD = $(LTLIBTHREAD) ../gnulib/lib/libgnu.la
+libguestfs_la_LIBADD = $(LIBPCRE) $(LIBMAGIC) $(LTLIBTHREAD) ../gnulib/lib/libgnu.la
 
 # Make libguestfs include the convenience library.
 noinst_LTLIBRARIES = libprotocol.la
diff --git a/src/generator.ml b/src/generator.ml
index 6791a6a4..77c76424 100755
--- a/src/generator.ml
+++ b/src/generator.ml
@@ -940,6 +940,134 @@ to specify the QEMU interface emulation to use at run time.");
 This is the same as C<guestfs_add_drive_ro> but it allows you
 to specify the QEMU interface emulation to use at run time.");
 
+  ("file_architecture", (RString "arch", [Pathname "filename"]), -1, [],
+   [InitISOFS, Always, TestOutput (
+      [["file_architecture"; "/bin-i586-dynamic"]], "i386");
+    InitISOFS, Always, TestOutput (
+      [["file_architecture"; "/bin-sparc-dynamic"]], "sparc");
+    InitISOFS, Always, TestOutput (
+      [["file_architecture"; "/bin-win32.exe"]], "i386");
+    InitISOFS, Always, TestOutput (
+      [["file_architecture"; "/bin-win64.exe"]], "x86_64");
+    InitISOFS, Always, TestOutput (
+      [["file_architecture"; "/bin-x86_64-dynamic"]], "x86_64");
+    InitISOFS, Always, TestOutput (
+      [["file_architecture"; "/lib-i586.so"]], "i386");
+    InitISOFS, Always, TestOutput (
+      [["file_architecture"; "/lib-sparc.so"]], "sparc");
+    InitISOFS, Always, TestOutput (
+      [["file_architecture"; "/lib-win32.dll"]], "i386");
+    InitISOFS, Always, TestOutput (
+      [["file_architecture"; "/lib-win64.dll"]], "x86_64");
+    InitISOFS, Always, TestOutput (
+      [["file_architecture"; "/lib-x86_64.so"]], "x86_64");
+    InitISOFS, Always, TestOutput (
+      [["file_architecture"; "/initrd-x86_64.img"]], "x86_64");
+    InitISOFS, Always, TestOutput (
+      [["file_architecture"; "/initrd-x86_64.img.gz"]], "x86_64");],
+   "detect the architecture of a binary file",
+   "\
+This detects the architecture of the binary C<filename>,
+and returns it if known.
+
+Currently defined architectures are:
+
+=over 4
+
+=item \"i386\"
+
+This string is returned for all 32 bit i386, i486, i586, i686 binaries
+irrespective of the precise processor requirements of the binary.
+
+=item \"x86_64\"
+
+64 bit x86-64.
+
+=item \"sparc\"
+
+32 bit SPARC.
+
+=item \"sparc64\"
+
+64 bit SPARC V9 and above.
+
+=item \"ia64\"
+
+Intel Itanium.
+
+=item \"ppc\"
+
+32 bit Power PC.
+
+=item \"ppc64\"
+
+64 bit Power PC.
+
+=back
+
+Libguestfs may return other architecture strings in future.
+
+The function works on at least the following types of files:
+
+=over 4
+
+=item *
+
+many types of Un*x and Linux binary
+
+=item *
+
+many types of Un*x and Linux shared library
+
+=item *
+
+Windows Win32 and Win64 binaries
+
+=item *
+
+Windows Win32 and Win64 DLLs
+
+Win32 binaries and DLLs return C<i386>.
+
+Win64 binaries and DLLs return C<x86_64>.
+
+=item *
+
+Linux kernel modules
+
+=item *
+
+Linux new-style initrd images
+
+=item *
+
+some non-x86 Linux vmlinuz kernels
+
+=back
+
+What it can't do currently:
+
+=over 4
+
+=item *
+
+static libraries (libfoo.a)
+
+=item *
+
+Linux old-style initrd as compressed ext2 filesystem (RHEL 3)
+
+=item *
+
+x86 Linux vmlinuz kernels
+
+x86 vmlinuz images (bzImage format) consist of a mix of 16-, 32- and
+compressed code, and are horribly hard to unpack.  If you want to find
+the architecture of a kernel, use the architecture of the associated
+initrd or kernel module(s) instead.
+
+=back");
+
 ]
 
 (* daemon_functions are any functions which cause some action
diff --git a/src/inspect.c b/src/inspect.c
new file mode 100644
index 00000000..d19e23b6
--- /dev/null
+++ b/src/inspect.c
@@ -0,0 +1,280 @@
+/* libguestfs
+ * Copyright (C) 2010 Red Hat Inc.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include <config.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <inttypes.h>
+#include <unistd.h>
+#include <string.h>
+#include <sys/stat.h>
+
+#include <pcre.h>
+#include <magic.h>
+
+#include "ignore-value.h"
+
+#include "guestfs.h"
+#include "guestfs-internal.h"
+#include "guestfs-internal-actions.h"
+#include "guestfs_protocol.h"
+
+/* Compile all the regular expressions once when the shared library is
+ * loaded.  PCRE is thread safe so we're supposedly OK here if
+ * multiple threads call into the libguestfs API functions below
+ * simultaneously.
+ */
+static pcre *re_file_elf;
+static pcre *re_file_win64;
+static pcre *re_elf_ppc64;
+
+static void compile_regexps (void) __attribute__((constructor));
+static void
+compile_regexps (void)
+{
+  const char *err;
+  int offset;
+
+#define COMPILE(re,pattern,options)                                     \
+  do {                                                                  \
+    re = pcre_compile ((pattern), (options), &err, &offset, NULL);      \
+    if (re == NULL) {                                                   \
+      ignore_value (write (2, err, strlen (err)));                      \
+      abort ();                                                         \
+    }                                                                   \
+  } while (0)
+
+  COMPILE (re_file_elf,
+           "ELF.*(?:executable|shared object|relocatable), (.+?),", 0);
+  COMPILE (re_elf_ppc64, "64.*PowerPC", 0);
+}
+
+/* Match a regular expression which contains no captures.  Returns
+ * true if it matches or false if it doesn't.
+ */
+static int
+match (guestfs_h *g, const char *str, const pcre *re)
+{
+  size_t len = strlen (str);
+  int vec[30], r;
+
+  r = pcre_exec (re, NULL, str, len, 0, 0, vec, sizeof vec / sizeof vec[0]);
+  if (r == PCRE_ERROR_NOMATCH)
+    return 0;
+  if (r != 1) {
+    /* Internal error -- should not happen. */
+    fprintf (stderr, "libguestfs: %s: %s: internal error: pcre_exec returned unexpected error code %d when matching against the string \"%s\"\n",
+             __FILE__, __func__, r, str);
+    return 0;
+  }
+
+  return 1;
+}
+
+/* Match a regular expression which contains exactly one capture.  If
+ * the string matches, return the capture, otherwise return NULL.  The
+ * caller must free the result.
+ */
+static char *
+match1 (guestfs_h *g, const char *str, const pcre *re)
+{
+  size_t len = strlen (str);
+  int vec[30], r;
+
+  r = pcre_exec (re, NULL, str, len, 0, 0, vec, sizeof vec / sizeof vec[0]);
+  if (r == PCRE_ERROR_NOMATCH)
+    return NULL;
+  if (r != 2) {
+    /* Internal error -- should not happen. */
+    fprintf (stderr, "libguestfs: %s: %s: internal error: pcre_exec returned unexpected error code %d when matching against the string \"%s\"\n",
+             __FILE__, __func__, r, str);
+    return NULL;
+  }
+
+  return safe_strndup (g, &str[vec[2]], vec[3]-vec[2]);
+}
+
+/* Convert output from 'file' command on ELF files to the canonical
+ * architecture string.  Caller must free the result.
+ */
+static char *
+canonical_elf_arch (guestfs_h *g, const char *elf_arch)
+{
+  const char *r;
+
+  if (strstr (elf_arch, "Intel 80386"))
+    r = "i386";
+  else if (strstr (elf_arch, "Intel 80486"))
+    r = "i486";
+  else if (strstr (elf_arch, "x86-64"))
+    r = "x86_64";
+  else if (strstr (elf_arch, "AMD x86-64"))
+    r = "x86_64";
+  else if (strstr (elf_arch, "SPARC32"))
+    r = "sparc";
+  else if (strstr (elf_arch, "SPARC V9"))
+    r = "sparc64";
+  else if (strstr (elf_arch, "IA-64"))
+    r = "ia64";
+  else if (match (g, elf_arch, re_elf_ppc64))
+    r = "ppc64";
+  else if (strstr (elf_arch, "PowerPC"))
+    r = "ppc";
+  else
+    r = elf_arch;
+
+  char *ret = safe_strdup (g, r);
+  return ret;
+}
+
+static int
+is_regular_file (const char *filename)
+{
+  struct stat statbuf;
+
+  return lstat (filename, &statbuf) == 0 && S_ISREG (statbuf.st_mode);
+}
+
+/* Download and uncompress the cpio file to find binaries within.
+ * Notes:
+ * (1) Two lists must be identical.
+ * (2) Implicit limit of 31 bytes for length of each element (see code
+ * below).
+ */
+#define INITRD_BINARIES1 "bin/ls bin/rm bin/modprobe sbin/modprobe bin/sh bin/bash bin/dash bin/nash"
+#define INITRD_BINARIES2 {"bin/ls", "bin/rm", "bin/modprobe", "sbin/modprobe", "bin/sh", "bin/bash", "bin/dash", "bin/nash"}
+
+static char *
+cpio_arch (guestfs_h *g, const char *file, const char *path)
+{
+  char *ret = NULL;
+
+  const char *method;
+  if (strstr (file, "gzip"))
+    method = "zcat";
+  else if (strstr (file, "bzip2"))
+    method = "bzcat";
+  else
+    method = "cat";
+
+  char dir[] = "/tmp/initrd.XXXXXX";
+#define dir_len (sizeof dir)
+  if (mkdtemp (dir) == NULL) {
+    perrorf (g, "mkdtemp");
+    goto out;
+  }
+
+  char dir_initrd[dir_len + 16];
+  snprintf (dir_initrd, dir_len + 16, "%s/initrd", dir);
+  if (guestfs_download (g, path, dir_initrd) == -1)
+    goto out;
+
+  char cmd[dir_len + 256];
+  snprintf (cmd, dir_len + 256,
+            "cd %s && %s initrd | cpio --quiet -id " INITRD_BINARIES1,
+            dir, method);
+  int r = system (cmd);
+  if (r == -1 || WEXITSTATUS (r) != 0) {
+    perrorf (g, "cpio command failed");
+    goto out;
+  }
+
+  char bin[dir_len + 32];
+  const char *bins[] = INITRD_BINARIES2;
+  size_t i;
+  for (i = 0; i < sizeof bins / sizeof bins[0]; ++i) {
+    snprintf (bin, dir_len + 32, "%s/%s", dir, bins[i]);
+
+    if (is_regular_file (bin)) {
+      int flags = g->verbose ? MAGIC_DEBUG : 0;
+      flags |= MAGIC_ERROR | MAGIC_RAW;
+
+      magic_t m = magic_open (flags);
+      if (m == NULL) {
+        perrorf (g, "magic_open");
+        goto out;
+      }
+
+      if (magic_load (m, NULL) == -1) {
+        perrorf (g, "magic_load: default magic database file");
+        magic_close (m);
+        goto out;
+      }
+
+      const char *line = magic_file (m, bin);
+      if (line == NULL) {
+        perrorf (g, "magic_file: %s", bin);
+        magic_close (m);
+        goto out;
+      }
+
+      char *elf_arch;
+      if ((elf_arch = match1 (g, line, re_file_elf)) != NULL) {
+        ret = canonical_elf_arch (g, elf_arch);
+        free (elf_arch);
+        magic_close (m);
+        goto out;
+      }
+      magic_close (m);
+    }
+  }
+  error (g, "file_architecture: could not determine architecture of cpio archive");
+
+ out:
+  /* Free up the temporary directory.  Note the directory name cannot
+   * contain shell meta-characters because of the way it was
+   * constructed above.
+   */
+  snprintf (cmd, dir_len + 256, "rm -rf %s", dir);
+  ignore_value (system (cmd));
+
+  return ret;
+#undef dir_len
+}
+
+char *
+guestfs__file_architecture (guestfs_h *g, const char *path)
+{
+  char *file = NULL;
+  char *elf_arch = NULL;
+  char *ret = NULL;
+
+  /* Get the output of the "file" command.  Note that because this
+   * runs in the daemon, LANG=C so it's in English.
+   */
+  file = guestfs_file (g, path);
+  if (file == NULL)
+    return NULL;
+
+  if ((elf_arch = match1 (g, file, re_file_elf)) != NULL)
+    ret = canonical_elf_arch (g, elf_arch);
+  else if (strstr (file, "PE32 executable"))
+    ret = safe_strdup (g, "i386");
+  else if (strstr (file, "PE32+ executable"))
+    ret = safe_strdup (g, "x86_64");
+  else if (strstr (file, "cpio archive"))
+    ret = cpio_arch (g, file, path);
+  else
+    error (g, "file_architecture: unknown architecture: %s", path);
+
+  free (file);
+  free (elf_arch);
+  return ret;                   /* caller frees */
+}