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[PATCH 1/2] Add an optional "alias" attribute to syscall entries.
- From: John Baldwin <jhb at FreeBSD dot org>
- To: gdb-patches at sourceware dot org
- Date: Wed, 3 Oct 2018 10:30:04 -0700
- Subject: [PATCH 1/2] Add an optional "alias" attribute to syscall entries.
- References: <20181003173005.19581-1-jhb@FreeBSD.org>
When setting a syscall catchpoint by name, catch syscalls whose name
or alias matches the requested string.
When the ABI of a system call is changed in the FreeBSD kernel, this
is implemented by leaving a compatability system call using the old
ABI at the existing "slot" and allocating a new system call for the
version using the new ABI. For example, new fields were added to the
'struct kevent' used by the kevent() system call in FreeBSD 12. The
previous kevent() system call in FreeBSD 12 kernels is now called
freebsd11_kevent() and is still used by older binaries compiled
against the older ABI. The freebsd11_kevent() system call can be
tagged with an "alias" attribute of "kevent" permitting 'catch syscall
kevent' to catch both system calls and providing the expected user
behavior for both old and new binaries. It also provides the expected
behavior if GDB is compiled on an older host (such as a FreeBSD 11
host).
gdb/ChangeLog:
* break-catch-syscall.c (catch_syscall_split_args): Update for
get_syscalls_by_name returning a vector.
* gdbarch.sh (UNKNOWN_SYSCALL): Remove.
* gdbarch.h: Regenerate.
* syscalls/gdb-syscalls.dtd (syscall): Add alias attribute.
* xml-syscall.c [!HAVE_LIBEXPAT] (get_syscalls_by_name): Rename
from get_syscall_by_name. Now returns a vector of integers.
[HAVE_LIBEXPAT] (struct syscall_desc): Add alias member.
(syscall_create_syscall_desc): Add alias parameter and pass it to
syscall_desc constructor.
(syscall_start_syscall): Handle alias attribute.
(syscall_attr): Add alias attribute.
(xml_get_syscalls_by_name): Rename from xml_get_syscall_number.
Now returns a vector of integers. Add syscalls whose alias or
name matches the requested name.
(get_syscalls_by_name): Rename from get_syscall_by_name. Now
returns a vector of integers.
* xml-syscall.h (get_syscalls_by_name): Likewise.
---
gdb/ChangeLog | 21 +++++++++++++++
gdb/break-catch-syscall.c | 11 ++++----
gdb/gdbarch.h | 3 ---
gdb/gdbarch.sh | 3 ---
gdb/syscalls/gdb-syscalls.dtd | 1 +
gdb/xml-syscall.c | 49 +++++++++++++++++++----------------
gdb/xml-syscall.h | 8 +++---
7 files changed, 59 insertions(+), 37 deletions(-)
diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index e239f201fa..1f679b48ed 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,24 @@
+2018-10-03 John Baldwin <jhb@FreeBSD.org>
+
+ * break-catch-syscall.c (catch_syscall_split_args): Update for
+ get_syscalls_by_name returning a vector.
+ * gdbarch.sh (UNKNOWN_SYSCALL): Remove.
+ * gdbarch.h: Regenerate.
+ * syscalls/gdb-syscalls.dtd (syscall): Add alias attribute.
+ * xml-syscall.c [!HAVE_LIBEXPAT] (get_syscalls_by_name): Rename
+ from get_syscall_by_name. Now returns a vector of integers.
+ [HAVE_LIBEXPAT] (struct syscall_desc): Add alias member.
+ (syscall_create_syscall_desc): Add alias parameter and pass it to
+ syscall_desc constructor.
+ (syscall_start_syscall): Handle alias attribute.
+ (syscall_attr): Add alias attribute.
+ (xml_get_syscalls_by_name): Rename from xml_get_syscall_number.
+ Now returns a vector of integers. Add syscalls whose alias or
+ name matches the requested name.
+ (get_syscalls_by_name): Rename from get_syscall_by_name. Now
+ returns a vector of integers.
+ * xml-syscall.h (get_syscalls_by_name): Likewise.
+
2018-10-02 Tom Tromey <tom@tromey.com>
* aarch64-linux-tdep.c (aarch64_linux_sigframe_init): Use pulongest.
diff --git a/gdb/break-catch-syscall.c b/gdb/break-catch-syscall.c
index 93ef74c249..e9e370f4bf 100644
--- a/gdb/break-catch-syscall.c
+++ b/gdb/break-catch-syscall.c
@@ -431,18 +431,19 @@ catch_syscall_split_args (const char *arg)
}
else
{
- /* We have a name. Let's check if it's valid and convert it
- to a number. */
- get_syscall_by_name (gdbarch, cur_name, &s);
+ /* We have a name. Let's check if it's valid and fetch a
+ list of matching numbers. */
+ std::vector<int> numbers = get_syscalls_by_name (gdbarch, cur_name);
- if (s.number == UNKNOWN_SYSCALL)
+ if (numbers.empty ())
/* Here we have to issue an error instead of a warning,
because GDB cannot do anything useful if there's no
syscall number to be caught. */
error (_("Unknown syscall name '%s'."), cur_name);
/* Ok, it's valid. */
- result.push_back (s.number);
+ for (int number : numbers)
+ result.push_back (number);
}
}
diff --git a/gdb/gdbarch.h b/gdb/gdbarch.h
index fc2f1a84a1..6b7afe4a5c 100644
--- a/gdb/gdbarch.h
+++ b/gdb/gdbarch.h
@@ -1569,9 +1569,6 @@ typedef ULONGEST (gdbarch_type_align_ftype) (struct gdbarch *gdbarch, struct typ
extern ULONGEST gdbarch_type_align (struct gdbarch *gdbarch, struct type *type);
extern void set_gdbarch_type_align (struct gdbarch *gdbarch, gdbarch_type_align_ftype *type_align);
-/* Definition for an unknown syscall, used basically in error-cases. */
-#define UNKNOWN_SYSCALL (-1)
-
extern struct gdbarch_tdep *gdbarch_tdep (struct gdbarch *gdbarch);
diff --git a/gdb/gdbarch.sh b/gdb/gdbarch.sh
index 670ac30c03..ee74acfd2a 100755
--- a/gdb/gdbarch.sh
+++ b/gdb/gdbarch.sh
@@ -1393,9 +1393,6 @@ done
# close it off
cat <<EOF
-/* Definition for an unknown syscall, used basically in error-cases. */
-#define UNKNOWN_SYSCALL (-1)
-
extern struct gdbarch_tdep *gdbarch_tdep (struct gdbarch *gdbarch);
diff --git a/gdb/syscalls/gdb-syscalls.dtd b/gdb/syscalls/gdb-syscalls.dtd
index c2aa478aa4..6aa73f288a 100644
--- a/gdb/syscalls/gdb-syscalls.dtd
+++ b/gdb/syscalls/gdb-syscalls.dtd
@@ -12,4 +12,5 @@
<!ATTLIST syscall
name CDATA #REQUIRED
number CDATA #REQUIRED
+ alias CDATA #IMPLIED
groups CDATA #IMPLIED>
diff --git a/gdb/xml-syscall.c b/gdb/xml-syscall.c
index bf17642911..a96d377fac 100644
--- a/gdb/xml-syscall.c
+++ b/gdb/xml-syscall.c
@@ -61,13 +61,11 @@ get_syscall_by_number (struct gdbarch *gdbarch,
s->name = NULL;
}
-void
-get_syscall_by_name (struct gdbarch *gdbarch, const char *syscall_name,
- struct syscall *s)
+std::vector<int>
+get_syscalls_by_name (struct gdbarch *gdbarch, const char *syscall_name)
{
syscall_warn_user ();
- s->number = UNKNOWN_SYSCALL;
- s->name = syscall_name;
+ return std::vector<int> ();
}
const char **
@@ -96,8 +94,8 @@ get_syscall_group_names (struct gdbarch *gdbarch)
/* Structure which describes a syscall. */
struct syscall_desc
{
- syscall_desc (int number_, std::string name_)
- : number (number_), name (name_)
+ syscall_desc (int number_, std::string name_, std::string alias_)
+ : number (number_), name (name_), alias(alias_)
{}
/* The syscall number. */
@@ -107,6 +105,10 @@ struct syscall_desc
/* The syscall name. */
std::string name;
+
+ /* An optional alias. */
+
+ std::string alias;
};
typedef std::unique_ptr<syscall_desc> syscall_desc_up;
@@ -206,10 +208,10 @@ syscall_group_add_syscall (struct syscalls_info *syscalls_info,
static void
syscall_create_syscall_desc (struct syscalls_info *syscalls_info,
- const char *name, int number,
+ const char *name, int number, const char *alias,
char *groups)
{
- syscall_desc *sysdesc = new syscall_desc (number, name);
+ syscall_desc *sysdesc = new syscall_desc (number, name, alias ?: "");
syscalls_info->syscalls.emplace_back (sysdesc);
@@ -234,6 +236,7 @@ syscall_start_syscall (struct gdb_xml_parser *parser,
/* syscall info. */
char *name = NULL;
int number = 0;
+ char *alias = NULL;
char *groups = NULL;
for (const gdb_xml_value &attr : attributes)
@@ -242,6 +245,8 @@ syscall_start_syscall (struct gdb_xml_parser *parser,
name = (char *) attr.value.get ();
else if (strcmp (attr.name, "number") == 0)
number = * (ULONGEST *) attr.value.get ();
+ else if (strcmp (attr.name, "alias") == 0)
+ alias = (char *) attr.value.get ();
else if (strcmp (attr.name, "groups") == 0)
groups = (char *) attr.value.get ();
else
@@ -250,7 +255,8 @@ syscall_start_syscall (struct gdb_xml_parser *parser,
}
gdb_assert (name);
- syscall_create_syscall_desc (data->syscalls_info, name, number, groups);
+ syscall_create_syscall_desc (data->syscalls_info, name, number, alias,
+ groups);
}
@@ -258,6 +264,7 @@ 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 },
+ { "alias", GDB_XML_AF_OPTIONAL, NULL, NULL },
{ "groups", GDB_XML_AF_OPTIONAL, NULL, NULL },
{ NULL, GDB_XML_AF_NONE, NULL, NULL }
};
@@ -389,21 +396,21 @@ syscall_group_get_group_by_name (const struct syscalls_info *syscalls_info,
return NULL;
}
-static int
-xml_get_syscall_number (struct gdbarch *gdbarch,
- const char *syscall_name)
+static std::vector<int>
+xml_get_syscalls_by_name (struct gdbarch *gdbarch, const char *syscall_name)
{
struct syscalls_info *syscalls_info = gdbarch_syscalls_info (gdbarch);
+ std::vector<int> syscalls;
if (syscalls_info == NULL
|| syscall_name == NULL)
- return UNKNOWN_SYSCALL;
+ return syscalls;
for (const syscall_desc_up &sysdesc : syscalls_info->syscalls)
- if (sysdesc->name == syscall_name)
- return sysdesc->number;
+ if (sysdesc->name == syscall_name || sysdesc->alias == syscall_name)
+ syscalls.push_back (sysdesc->number);
- return UNKNOWN_SYSCALL;
+ return syscalls;
}
static const char *
@@ -522,14 +529,12 @@ get_syscall_by_number (struct gdbarch *gdbarch,
s->name = xml_get_syscall_name (gdbarch, syscall_number);
}
-void
-get_syscall_by_name (struct gdbarch *gdbarch,
- const char *syscall_name, struct syscall *s)
+std::vector<int>
+get_syscalls_by_name (struct gdbarch *gdbarch, const char *syscall_name)
{
init_syscalls_info (gdbarch);
- s->number = xml_get_syscall_number (gdbarch, syscall_name);
- s->name = syscall_name;
+ return xml_get_syscalls_by_name (gdbarch, syscall_name);
}
const char **
diff --git a/gdb/xml-syscall.h b/gdb/xml-syscall.h
index 4429d66400..86713097b3 100644
--- a/gdb/xml-syscall.h
+++ b/gdb/xml-syscall.h
@@ -38,11 +38,11 @@ void set_xml_syscall_file_name (struct gdbarch *gdbarch,
void get_syscall_by_number (struct gdbarch *gdbarch,
int syscall_number, struct syscall *s);
-/* Function that retrieves the syscall number corresponding to the given
- name. It puts the requested information inside 'struct syscall'. */
+/* Function that retrieves the syscall numbers corresponding to the given
+ name. The list of syscall numbers are returned in a vector. */
-void get_syscall_by_name (struct gdbarch *gdbarch,
- const char *syscall_name, struct syscall *s);
+std::vector<int> get_syscalls_by_name (struct gdbarch *gdbarch,
+ const char *syscall_name);
/* Function used to retrieve the list of syscalls in the system. This list
is returned as an array of strings. Returns the list of syscalls in the
--
2.18.0