Libguestfs - Mar 2017 - Re: [PATCH] inspect: improve detection of Mageia install discs

Check for a "product.id" file in an architecture-specific subdirectory
of the main partition, and use its data to improve the data on the
media.

Only Mageia as distribution name is recognized there, since most
probably this file will not be available on other distros.
---
 lib/inspect-fs-cd.c | 76 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 76 insertions(+)

diff --git a/lib/inspect-fs-cd.c b/lib/inspect-fs-cd.c
index 278386e..9c809b4 100644
--- a/lib/inspect-fs-cd.c
+++ b/lib/inspect-fs-cd.c
@@ -21,6 +21,8 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <libintl.h>
+#include <inttypes.h>
 
 #ifdef HAVE_ENDIAN_H
 #include <endian.h>
@@ -432,10 +434,72 @@ check_w2k3_installer_root (guestfs_h *g, struct inspect_fs
*fs,
   return 0;
 }
 
+/* Read the data from a product.id-like file.
+ *
+ * This is an old file, mostly used in Mandriva-based systems (still including
+ * Mageia).  A very minimal documentation for it is:
+ * - https://wiki.mageia.org/en/Product_id
+ * - http://wiki.mandriva.com/en/Product_id (old URL, defunct)
+ */
+static int
+check_product_id_installer_root (guestfs_h *g, struct inspect_fs *fs,
+                                 const char *filename)
+{
+  int64_t size;
+  CLEANUP_FREE_STRING_LIST char **lines = NULL;
+  const char *elem;
+  char *saveptr;
+
+  fs->type = OS_TYPE_LINUX;
+
+  /* Don't trust guestfs_head_n not to break with very large files.
+   * Check the file size is something reasonable first.
+   */
+  size = guestfs_filesize (g, filename);
+  if (size == -1)
+    /* guestfs_filesize failed and has already set error in handle */
+    return -1;
+  if (size > MAX_SMALL_FILE_SIZE) {
+    error (g, _("size of %s is unreasonably large (%" PRIi64 "
bytes)"),
+           filename, size);
+    return -1;
+  }
+
+  lines = guestfs_head_n (g, 1, filename);
+  if (lines == NULL)
+    return -1;
+
+  elem = strtok_r (lines[0], ",", &saveptr);
+  while (elem) {
+    const char *equal = strchr (elem, '=');
+    if (equal == NULL || equal == elem)
+      return -1;
+
+    const char *value = equal + 1;
+
+    if (STRPREFIX (elem, "distribution=")) {
+      if (STREQ (value, "Mageia"))
+        fs->distro = OS_DISTRO_MAGEIA;
+    } else if (STRPREFIX (elem, "version=")) {
+      if (guestfs_int_version_from_x_y_or_x (g, &fs->version, value) ==
-1)
+        return -1;
+    } else if (STRPREFIX (elem, "arch=")) {
+      fs->arch = safe_strdup (g, value);
+    }
+
+    elem = strtok_r (NULL, ",", &saveptr);
+  }
+
+  /* Not found. */
+  return 0;
+}
+
 /* The currently mounted device is very likely to be an installer. */
 int
 guestfs_int_check_installer_root (guestfs_h *g, struct inspect_fs *fs)
 {
+  CLEANUP_FREE_STRING_LIST char **paths = NULL;
+
   /* The presence of certain files indicates a live CD.
    *
    * XXX Fedora netinst contains a ~120MB squashfs called
@@ -495,6 +559,18 @@ guestfs_int_check_installer_root (guestfs_h *g, struct
inspect_fs *fs)
       return -1;
   }
 
+  /* Linux with /{i586,x86_64,etc}/product.id (typically found in Mandriva
+   * and Mageia).  Usually there should be just one around, so we use the
+   * first one found.
+   */
+  paths = guestfs_glob_expand (g, "/*/product.id");
+  if (paths == NULL)
+    return -1;
+  if (paths[0] != NULL) {
+    if (check_product_id_installer_root (g, fs, paths[0]) == -1)
+      return -1;
+  }
+
   return 0;
 }
 
-- 
2.9.3

On Wed, Mar 22, 2017 at 05:16:34PM +0100, Pino Toscano
wrote:
> Check for a "product.id" file in an architecture-specific
subdirectory
> of the main partition, and use its data to improve the data on the
> media.
> 
> Only Mageia as distribution name is recognized there, since most
> probably this file will not be available on other distros.
> ---
>  lib/inspect-fs-cd.c | 76
+++++++++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 76 insertions(+)
> 
> diff --git a/lib/inspect-fs-cd.c b/lib/inspect-fs-cd.c
> index 278386e..9c809b4 100644
> --- a/lib/inspect-fs-cd.c
> +++ b/lib/inspect-fs-cd.c
> @@ -21,6 +21,8 @@
>  #include <stdio.h>
>  #include <stdlib.h>
>  #include <string.h>
> +#include <libintl.h>
> +#include <inttypes.h>
>  
>  #ifdef HAVE_ENDIAN_H
>  #include <endian.h>
> @@ -432,10 +434,72 @@ check_w2k3_installer_root (guestfs_h *g, struct
inspect_fs *fs,
>    return 0;
>  }
>  
> +/* Read the data from a product.id-like file.
> + *
> + * This is an old file, mostly used in Mandriva-based systems (still
including
> + * Mageia).  A very minimal documentation for it is:
> + * - https://wiki.mageia.org/en/Product_id
> + * - http://wiki.mandriva.com/en/Product_id (old URL, defunct)
> + */
> +static int
> +check_product_id_installer_root (guestfs_h *g, struct inspect_fs *fs,
> +                                 const char *filename)
> +{
> +  int64_t size;
> +  CLEANUP_FREE_STRING_LIST char **lines = NULL;
> +  const char *elem;
> +  char *saveptr;
> +
> +  fs->type = OS_TYPE_LINUX;
> +
> +  /* Don't trust guestfs_head_n not to break with very large files.
> +   * Check the file size is something reasonable first.
> +   */
> +  size = guestfs_filesize (g, filename);
> +  if (size == -1)
> +    /* guestfs_filesize failed and has already set error in handle */
> +    return -1;
> +  if (size > MAX_SMALL_FILE_SIZE) {
> +    error (g, _("size of %s is unreasonably large (%" PRIi64
" bytes)"),
> +           filename, size);
> +    return -1;
> +  }
> +
> +  lines = guestfs_head_n (g, 1, filename);
> +  if (lines == NULL)
> +    return -1;
Could the above code be replaced by a call to
guestfs_int_first_line_of_file ?
> +  elem = strtok_r (lines[0], ",", &saveptr);
You can probably use strtok here [I think?] if it's simpler.

Rich.
> +  while (elem) {
> +    const char *equal = strchr (elem, '=');
> +    if (equal == NULL || equal == elem)
> +      return -1;
> +
> +    const char *value = equal + 1;
> +
> +    if (STRPREFIX (elem, "distribution=")) {
> +      if (STREQ (value, "Mageia"))
> +        fs->distro = OS_DISTRO_MAGEIA;
> +    } else if (STRPREFIX (elem, "version=")) {
> +      if (guestfs_int_version_from_x_y_or_x (g, &fs->version,
value) == -1)
> +        return -1;
> +    } else if (STRPREFIX (elem, "arch=")) {
> +      fs->arch = safe_strdup (g, value);
> +    }
> +
> +    elem = strtok_r (NULL, ",", &saveptr);
> +  }
> +
> +  /* Not found. */
> +  return 0;
> +}
> +
>  /* The currently mounted device is very likely to be an installer. */
>  int
>  guestfs_int_check_installer_root (guestfs_h *g, struct inspect_fs *fs)
>  {
> +  CLEANUP_FREE_STRING_LIST char **paths = NULL;
> +
>    /* The presence of certain files indicates a live CD.
>     *
>     * XXX Fedora netinst contains a ~120MB squashfs called
> @@ -495,6 +559,18 @@ guestfs_int_check_installer_root (guestfs_h *g, struct
inspect_fs *fs)
>        return -1;
>    }
>  
> +  /* Linux with /{i586,x86_64,etc}/product.id (typically found in Mandriva
> +   * and Mageia).  Usually there should be just one around, so we use the
> +   * first one found.
> +   */
> +  paths = guestfs_glob_expand (g, "/*/product.id");
> +  if (paths == NULL)
> +    return -1;
> +  if (paths[0] != NULL) {
> +    if (check_product_id_installer_root (g, fs, paths[0]) == -1)
> +      return -1;
> +  }
> +
>    return 0;
>  }
>  
> -- 
> 2.9.3
> 
> _______________________________________________
> Libguestfs mailing list
> Libguestfs@redhat.com
> https://www.redhat.com/mailman/listinfo/libguestfs
-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
Read my programming and virtualization blog: http://rwmj.wordpress.com
virt-top is 'top' for virtual machines.  Tiny program with many
powerful monitoring features, net stats, disk stats, logging, etc.
http://people.redhat.com/~rjones/virt-top

On Wednesday, 22 March 2017 17:31:41 CET Richard W.M. Jones
wrote:
> On Wed, Mar 22, 2017 at 05:16:34PM +0100, Pino Toscano wrote:
> > Check for a "product.id" file in an architecture-specific
subdirectory
> > of the main partition, and use its data to improve the data on the
> > media.
> > 
> > Only Mageia as distribution name is recognized there, since most
> > probably this file will not be available on other distros.
> > ---
> >  lib/inspect-fs-cd.c | 76
+++++++++++++++++++++++++++++++++++++++++++++++++++++
> >  1 file changed, 76 insertions(+)
> > 
> > diff --git a/lib/inspect-fs-cd.c b/lib/inspect-fs-cd.c
> > index 278386e..9c809b4 100644
> > --- a/lib/inspect-fs-cd.c
> > +++ b/lib/inspect-fs-cd.c
> > @@ -21,6 +21,8 @@
> >  #include <stdio.h>
> >  #include <stdlib.h>
> >  #include <string.h>
> > +#include <libintl.h>
> > +#include <inttypes.h>
> >  
> >  #ifdef HAVE_ENDIAN_H
> >  #include <endian.h>
> > @@ -432,10 +434,72 @@ check_w2k3_installer_root (guestfs_h *g, struct
inspect_fs *fs,
> >    return 0;
> >  }
> >  
> > +/* Read the data from a product.id-like file.
> > + *
> > + * This is an old file, mostly used in Mandriva-based systems (still
including
> > + * Mageia).  A very minimal documentation for it is:
> > + * - https://wiki.mageia.org/en/Product_id
> > + * - http://wiki.mandriva.com/en/Product_id (old URL, defunct)
> > + */
> > +static int
> > +check_product_id_installer_root (guestfs_h *g, struct inspect_fs *fs,
> > +                                 const char *filename)
> > +{
> > +  int64_t size;
> > +  CLEANUP_FREE_STRING_LIST char **lines = NULL;
> > +  const char *elem;
> > +  char *saveptr;
> > +
> > +  fs->type = OS_TYPE_LINUX;
> > +
> > +  /* Don't trust guestfs_head_n not to break with very large
files.
> > +   * Check the file size is something reasonable first.
> > +   */
> > +  size = guestfs_filesize (g, filename);
> > +  if (size == -1)
> > +    /* guestfs_filesize failed and has already set error in handle */
> > +    return -1;
> > +  if (size > MAX_SMALL_FILE_SIZE) {
> > +    error (g, _("size of %s is unreasonably large (%"
PRIi64 " bytes)"),
> > +           filename, size);
> > +    return -1;
> > +  }
> > +
> > +  lines = guestfs_head_n (g, 1, filename);
> > +  if (lines == NULL)
> > +    return -1;
> 
> Could the above code be replaced by a call to
> guestfs_int_first_line_of_file ?
Indeed, good catch -- thanks!
> > +  elem = strtok_r (lines[0], ",", &saveptr);
> 
> You can probably use strtok here [I think?] if it's simpler.
I'd maybe if this was in the daemon, which runs single-threaded.
OTOH, using a non-reentrant strtok in the library might cause conflicts
with multithreaded applications using libguestfs.

Thanks,
-- 
Pino Toscano