[v6,1/5] Implemement support for groups of syscalls in the xml-syscall interface.

This is done by maintaining a list of syscall_group_desc for each
syscall group inside the syscalls_info structure.  Inside each
syscall_group_desc we have a vector of pointers to the syscalls that are
part of that group.

gdb/

	* syscalls/gdb-syscalls.dtd: Include group attribute to the
	syscall element.
	* xml-syscall.c (get_syscalls_by_group): New.
	(get_syscall_group_names): New.
	(struct syscall_group_desc): New structure to store group data.
	(struct syscalls_info): Include field to store the group list.
	(sysinfo_free_syscall_group_desc): New.
	(free_syscalls_info): Free group list.
	(syscall_group_create_syscall_group_desc): New.
	(syscall_group_add_syscall): New.
	(syscall_create_syscall_desc): Add syscall to its groups.
	(syscall_start_syscall): Load group attribute.
	(syscall_group_get_group_by_name): New.
	(xml_list_syscalls_by_group): New.
	(xml_list_of_groups): New.
	* xml-syscall.h (get_syscalls_by_group): Export function
	to retrieve a list of syscalls filtered by the group name.
	(get_syscall_group_names): Export function to retrieve the list
	of syscall groups.
---
 gdb/syscalls/gdb-syscalls.dtd |   3 +-
 gdb/xml-syscall.c             | 234 +++++++++++++++++++++++++++++++++++++++++-
 gdb/xml-syscall.h             |  16 +++
 3 files changed, 250 insertions(+), 3 deletions(-)

On Thursday, May 19 2016, Gabriel Krisman Bertazi wrote:

> This is done by maintaining a list of syscall_group_desc for each
> syscall group inside the syscalls_info structure.  Inside each
> syscall_group_desc we have a vector of pointers to the syscalls that are
> part of that group.
>
> gdb/
>
> 	* syscalls/gdb-syscalls.dtd: Include group attribute to the
> 	syscall element.
> 	* xml-syscall.c (get_syscalls_by_group): New.
> 	(get_syscall_group_names): New.
> 	(struct syscall_group_desc): New structure to store group data.
> 	(struct syscalls_info): Include field to store the group list.
> 	(sysinfo_free_syscall_group_desc): New.
> 	(free_syscalls_info): Free group list.
> 	(syscall_group_create_syscall_group_desc): New.
> 	(syscall_group_add_syscall): New.
> 	(syscall_create_syscall_desc): Add syscall to its groups.
> 	(syscall_start_syscall): Load group attribute.
> 	(syscall_group_get_group_by_name): New.
> 	(xml_list_syscalls_by_group): New.
> 	(xml_list_of_groups): New.
> 	* xml-syscall.h (get_syscalls_by_group): Export function
> 	to retrieve a list of syscalls filtered by the group name.
> 	(get_syscall_group_names): Export function to retrieve the list
> 	of syscall groups.
> ---
>  gdb/syscalls/gdb-syscalls.dtd |   3 +-
>  gdb/xml-syscall.c             | 234 +++++++++++++++++++++++++++++++++++++++++-
>  gdb/xml-syscall.h             |  16 +++
>  3 files changed, 250 insertions(+), 3 deletions(-)
>
> diff --git a/gdb/syscalls/gdb-syscalls.dtd b/gdb/syscalls/gdb-syscalls.dtd
> index 3deda12..de47d4d 100644
> --- a/gdb/syscalls/gdb-syscalls.dtd
> +++ b/gdb/syscalls/gdb-syscalls.dtd
> @@ -11,4 +11,5 @@
>  <!ELEMENT syscall		EMPTY>
>  <!ATTLIST syscall
>  	name			CDATA	#REQUIRED
> -	number			CDATA	#REQUIRED>
> +	number			CDATA	#REQUIRED
> +	groups			CDATA	#IMPLIED>
> diff --git a/gdb/xml-syscall.c b/gdb/xml-syscall.c
> index ceaf750..c7c307e 100644
> --- a/gdb/xml-syscall.c
> +++ b/gdb/xml-syscall.c
> @@ -77,6 +77,20 @@ get_syscall_names (struct gdbarch *gdbarch)
>    return NULL;
>  }
>  
> +struct syscall *
> +get_syscalls_by_group (struct gdbarch *gdbarch, const char *group)
> +{
> +  syscall_warn_user ();
> +  return NULL;
> +}
> +
> +const char **
> +get_syscall_group_names (struct gdbarch *gdbarch)
> +{
> +  syscall_warn_user ();
> +  return NULL;
> +}
> +
>  #else /* ! HAVE_LIBEXPAT */
>  
>  /* Structure which describes a syscall.  */
> @@ -92,6 +106,19 @@ typedef struct syscall_desc
>  } *syscall_desc_p;
>  DEF_VEC_P(syscall_desc_p);
>  
> +/* Structure of a syscall group.  */
> +typedef struct syscall_group_desc
> +{
> +  /* The group name.  */
> +
> +  char *name;
> +
> +  /* The syscalls that are part of the group.  */
> +
> +  VEC(syscall_desc_p) *syscalls;
> +} *syscall_group_desc_p;
> +DEF_VEC_P(syscall_group_desc_p);
> +
>  /* Structure that represents syscalls information.  */
>  struct syscalls_info
>  {
> @@ -99,6 +126,10 @@ struct syscalls_info
>  
>    VEC(syscall_desc_p) *syscalls;
>  
> +  /* The syscall groups.  */
> +
> +  VEC(syscall_group_desc_p) *groups;
> +
>    /* Variable that will hold the last known data-directory.  This is
>       useful to know whether we should re-read the XML info for the
>       target.  */
> @@ -126,11 +157,21 @@ syscalls_info_free_syscalls_desc (struct syscall_desc *sd)
>    xfree (sd->name);
>  }
>  
> +/* Free syscall_group_desc members but not the structure itself.  */
> +
> +static void
> +syscalls_info_free_syscall_group_desc (struct syscall_group_desc *sd)
> +{
> +  VEC_free (syscall_desc_p, sd->syscalls);
> +  xfree (sd->name);
> +}
> +
>  static void
>  free_syscalls_info (void *arg)
>  {
>    struct syscalls_info *syscalls_info = (struct syscalls_info *) arg;
>    struct syscall_desc *sysdesc;
> +  struct syscall_group_desc *groupdesc;
>    int i;
>  
>    xfree (syscalls_info->my_gdb_datadir);
> @@ -144,6 +185,17 @@ free_syscalls_info (void *arg)
>        VEC_free (syscall_desc_p, syscalls_info->syscalls);
>      }
>  
> +  if (syscalls_info->groups != NULL)
> +    {
> +      for (i = 0;
> +	   VEC_iterate (syscall_group_desc_p,
> +			syscalls_info->groups, i, groupdesc);
> +	   i++)
> +	syscalls_info_free_syscall_group_desc (groupdesc);
> +
> +      VEC_free (syscall_group_desc_p, syscalls_info->groups);
> +    }
> +
>    xfree (syscalls_info);
>  }
>  
> @@ -153,16 +205,73 @@ make_cleanup_free_syscalls_info (struct syscalls_info *syscalls_info)
>    return make_cleanup (free_syscalls_info, syscalls_info);
>  }
>  
> +/* Create a new syscall group.  Return pointer to the
> +   syscall_group_desc structure that represents the new group.  */
> +
> +static struct syscall_group_desc *
> +syscall_group_create_syscall_group_desc (struct syscalls_info *syscalls_info,
> +					 const char *group)
> +{
> +  struct syscall_group_desc *groupdesc = XCNEW (struct syscall_group_desc);
> +
> +  groupdesc->name = xstrdup (group);
> +
> +  VEC_safe_push (syscall_group_desc_p, syscalls_info->groups, groupdesc);
> +
> +  return groupdesc;
> +}
> +
> +/* Add a syscall to the group.  If group doesn't exist, create it.  */
> +
> +static void
> +syscall_group_add_syscall (struct syscalls_info *syscalls_info,
> +			   struct syscall_desc *syscall,
> +			   const char *group)
> +{
> +  struct syscall_group_desc *groupdesc;

Minor nit: assign NULL to this variable here.

> +  int i;
> +
> +  /* Search for an existing group.  */
> +  for (i = 0;
> +       VEC_iterate (syscall_group_desc_p, syscalls_info->groups, i, groupdesc);
> +       i++)
> +    {
> +      if (strcmp (groupdesc->name, group) == 0)
> +	break;
> +    }
> +
> +  if (groupdesc == NULL)
> +    {
> +      /* No group was found with this name.  We must create a new
> +	 one.  */
> +      groupdesc = syscall_group_create_syscall_group_desc (syscalls_info,
> +							   group);
> +    }
> +
> +  VEC_safe_push (syscall_desc_p, groupdesc->syscalls, syscall);
> +}
> +
>  static void
>  syscall_create_syscall_desc (struct syscalls_info *syscalls_info,
> -                             const char *name, int number)
> +			     const char *name, int number,
> +			     char *groups)
>  {
>    struct syscall_desc *sysdesc = XCNEW (struct syscall_desc);
> +  char *group;
>  
>    sysdesc->name = xstrdup (name);
>    sysdesc->number = number;
>  
>    VEC_safe_push (syscall_desc_p, syscalls_info->syscalls, sysdesc);
> +
> +  /*  Add syscall to its groups.  */
> +  if (groups != NULL)
> +    {
> +      for (group = strtok (groups, ",");
> +	   group != NULL;
> +	   group = strtok (NULL, ","))
> +	syscall_group_add_syscall (syscalls_info, sysdesc, group);
> +    }
>  }
>  
>  /* Handle the start of a <syscall> element.  */
> @@ -177,6 +286,7 @@ syscall_start_syscall (struct gdb_xml_parser *parser,
>    /* syscall info.  */
>    char *name = NULL;
>    int number = 0;
> +  char *groups = NULL;
>  
>    len = VEC_length (gdb_xml_value_s, attributes);
>  
> @@ -186,13 +296,15 @@ syscall_start_syscall (struct gdb_xml_parser *parser,
>          name = (char *) attrs[i].value;
>        else if (strcmp (attrs[i].name, "number") == 0)
>          number = * (ULONGEST *) attrs[i].value;
> +      else if (strcmp (attrs[i].name, "groups") == 0)
> +        groups = (char *) attrs[i].value;
>        else
>          internal_error (__FILE__, __LINE__,
>                          _("Unknown attribute name '%s'."), attrs[i].name);
>      }
>  
>    gdb_assert (name);
> -  syscall_create_syscall_desc (data->syscalls_info, name, number);
> +  syscall_create_syscall_desc (data->syscalls_info, name, number, groups);
>  }
>  
>  
> @@ -200,6 +312,7 @@ syscall_start_syscall (struct gdb_xml_parser *parser,
>  static const struct gdb_xml_attribute syscall_attr[] = {
>    { "number", GDB_XML_AF_NONE, gdb_xml_parse_attr_ulongest, NULL },
>    { "name", GDB_XML_AF_NONE, NULL, NULL },
> +  { "groups", GDB_XML_AF_OPTIONAL, NULL, NULL },
>    { NULL, GDB_XML_AF_NONE, NULL, NULL }
>  };
>  
> @@ -321,6 +434,34 @@ init_syscalls_info (struct gdbarch *gdbarch)
>    set_gdbarch_syscalls_info (gdbarch, syscalls_info);
>  }
>  
> +/* Search for a syscall group by its name.  Return syscall_group_desc
> +   structure for the group if found or NULL otherwise.  */
> +
> +static struct syscall_group_desc *
> +syscall_group_get_group_by_name (const struct syscalls_info *syscalls_info,
> +				 const char *group)
> +{
> +  struct syscall_group_desc *groupdesc;
> +  int i;
> +
> +  if (syscalls_info == NULL)
> +    return NULL;
> +
> +  if (group == NULL)
> +    return NULL;
> +
> +   /* Search for existing group.  */
> +  for (i = 0;
> +       VEC_iterate (syscall_group_desc_p, syscalls_info->groups, i, groupdesc);
> +       i++)
> +    {
> +      if (strcmp (groupdesc->name, group) == 0)
> +	return groupdesc;
> +    }
> +
> +  return NULL;
> +}
> +
>  static int
>  xml_get_syscall_number (struct gdbarch *gdbarch,
>                          const char *syscall_name)
> @@ -388,6 +529,75 @@ xml_list_of_syscalls (struct gdbarch *gdbarch)
>    return names;
>  }
>  
> +/* Iterate over the syscall_group_desc element to return a list of
> +   syscalls that are part of the given group, terminated by an empty
> +   element.  If the syscall group doesn't exist, return NULL.  */
> +
> +static struct syscall *
> +xml_list_syscalls_by_group (struct gdbarch *gdbarch, const char *group)
> +{
> +  struct syscalls_info *syscalls_info = gdbarch_syscalls_info (gdbarch);
> +  struct syscall_group_desc *groupdesc;
> +  struct syscall_desc *sysdesc;
> +  struct syscall *syscalls = NULL;
> +  int nsyscalls;
> +  int i;
> +
> +  if (syscalls_info == NULL)
> +    return NULL;
> +
> +  groupdesc = syscall_group_get_group_by_name (syscalls_info, group);
> +  if (groupdesc == NULL)
> +    return NULL;
> +
> +  nsyscalls = VEC_length (syscall_desc_p, groupdesc->syscalls);
> +  syscalls = (struct syscall*) xmalloc ((nsyscalls + 1)
> +					* sizeof (struct syscall));
> +
> +  for (i = 0;
> +       VEC_iterate (syscall_desc_p, groupdesc->syscalls, i, sysdesc);
> +       i++)
> +    {
> +      syscalls[i].name = sysdesc->name;
> +      syscalls[i].number = sysdesc->number;
> +    }
> +
> +  /* Add final element marker.  */
> +  syscalls[i].name = NULL;
> +  syscalls[i].number = 0;
> +
> +  return syscalls;
> +}
> +
> +/* Return a NULL terminated list of syscall groups or an empty list, if
> +   no syscall group is available.  Return NULL, if there is no syscall
> +   information available.  */
> +
> +static const char **
> +xml_list_of_groups (struct gdbarch *gdbarch)
> +{
> +  struct syscalls_info *syscalls_info = gdbarch_syscalls_info (gdbarch);
> +  struct syscall_group_desc *groupdesc;
> +  const char **names = NULL;
> +  int i;
> +  int ngroups;
> +
> +  if (syscalls_info == NULL)
> +    return NULL;
> +
> +  ngroups = VEC_length (syscall_group_desc_p, syscalls_info->groups);
> +  names = (const char**) xmalloc ((ngroups + 1) * sizeof (char *));
> +
> +  for (i = 0;
> +       VEC_iterate (syscall_group_desc_p, syscalls_info->groups, i, groupdesc);
> +       i++)
> +    names[i] = groupdesc->name;
> +
> +  names[i] = NULL;
> +
> +  return names;
> +}
> +
>  void
>  set_xml_syscall_file_name (struct gdbarch *gdbarch, const char *name)
>  {
> @@ -422,4 +632,24 @@ get_syscall_names (struct gdbarch *gdbarch)
>    return xml_list_of_syscalls (gdbarch);
>  }
>  
> +/* See comment in xml-syscall.h.  */
> +
> +struct syscall *
> +get_syscalls_by_group (struct gdbarch *gdbarch, const char *group)
> +{
> +  init_syscalls_info (gdbarch);
> +
> +  return xml_list_syscalls_by_group (gdbarch, group);
> +}
> +
> +/* See comment in xml-syscall.h.  */
> +
> +const char **
> +get_syscall_group_names (struct gdbarch *gdbarch)
> +{
> +  init_syscalls_info (gdbarch);
> +
> +  return xml_list_of_groups (gdbarch);
> +}
> +
>  #endif /* ! HAVE_LIBEXPAT */
> diff --git a/gdb/xml-syscall.h b/gdb/xml-syscall.h
> index b0dd401..407613e 100644
> --- a/gdb/xml-syscall.h
> +++ b/gdb/xml-syscall.h
> @@ -50,4 +50,20 @@ void get_syscall_by_name (struct gdbarch *gdbarch,
>  
>  const char **get_syscall_names (struct gdbarch *gdbarch);
>  
> +/* Function used to retrieve the list of syscalls of a given group in
> +   the system.  Return a list of syscalls that are element of the
> +   group, terminated by an empty element. The list is malloc'ed
> +   and must be freed by the caller.  If group doesn't exist, return
> +   NULL.  */
> +
> +struct syscall *get_syscalls_by_group (struct gdbarch *gdbarch,
> +				       const char *group);
> +
> +/* Function used to retrieve the list of syscall groups in the system.
> +   Return an array of strings terminated by a NULL element.  The list
> +   must be freed by the caller.  Return NULL if there is no syscall
> +   information available.  */
> +
> +const char **get_syscall_group_names (struct gdbarch *gdbarch);
> +
>  #endif /* XML_SYSCALL_H */
> -- 
> 2.4.11

Just one minor nit (above).  Otherwise, LGTM.