From patchwork Fri Nov 9 20:04:31 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: John Baldwin X-Patchwork-Id: 30098 Received: (qmail 35326 invoked by alias); 9 Nov 2018 20:04:53 -0000 Mailing-List: contact gdb-patches-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Unsubscribe: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sourceware.org Delivered-To: mailing list gdb-patches@sourceware.org Received: (qmail 35201 invoked by uid 89); 9 Nov 2018 20:04:50 -0000 Authentication-Results: sourceware.org; auth=none X-Spam-SWARE-Status: No, score=-25.1 required=5.0 tests=AWL, BAYES_00, GIT_PATCH_0, GIT_PATCH_1, GIT_PATCH_2, GIT_PATCH_3, SPF_HELO_PASS, SPF_SOFTFAIL, T_FILL_THIS_FORM_SHORT autolearn=ham version=3.3.2 spammy=sk:gdbarch, keyword, retrieve X-HELO: mail.baldwin.cx Received: from bigwig.baldwin.cx (HELO mail.baldwin.cx) (96.47.65.170) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with ESMTP; Fri, 09 Nov 2018 20:04:48 +0000 Received: from ralph.baldwin.cx (ralph.baldwin.cx [66.234.199.215]) by mail.baldwin.cx (Postfix) with ESMTPSA id BA29C10B709 for ; Fri, 9 Nov 2018 15:04:45 -0500 (EST) From: John Baldwin To: gdb-patches@sourceware.org Subject: [PATCH v3 2/3] Add an optional "alias" attribute to syscall entries. Date: Fri, 9 Nov 2018 12:04:31 -0800 Message-Id: <20181109200432.84491-3-jhb@FreeBSD.org> In-Reply-To: <20181109200432.84491-1-jhb@FreeBSD.org> References: <20181109200432.84491-1-jhb@FreeBSD.org> X-IsSubscribed: yes 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 compatibility 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: * NEWS: Add entry documenting system call aliases. * break-catch-syscall.c (catch_syscall_split_args): Pass 'result' to get_syscalls_by_name. * 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 accepts a reference to a vector of integers and returns a bool. [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 accepts a reference to a vector of integers and returns a bool. Add syscalls whose alias or name matches the requested name. (get_syscalls_by_name): Rename from get_syscall_by_name. Now accepts a reference to a vector of integers and returns a bool. * xml-syscall.h (get_syscalls_by_name): Likewise. --- gdb/ChangeLog | 24 ++++++++++++++ gdb/NEWS | 5 +++ gdb/break-catch-syscall.c | 11 ++----- gdb/gdbarch.h | 3 -- gdb/gdbarch.sh | 3 -- gdb/syscalls/gdb-syscalls.dtd | 1 + gdb/xml-syscall.c | 61 ++++++++++++++++++++--------------- gdb/xml-syscall.h | 10 +++--- 8 files changed, 74 insertions(+), 44 deletions(-) diff --git a/gdb/ChangeLog b/gdb/ChangeLog index 81faa2994d..002ea3253c 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,27 @@ +2018-11-09 John Baldwin + + * NEWS: Add entry documenting system call aliases. + * break-catch-syscall.c (catch_syscall_split_args): Pass 'result' + to get_syscalls_by_name. + * 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 accepts a reference to a vector of + integers and returns a bool. + [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 accepts a reference to a vector of integers and returns a + bool. Add syscalls whose alias or name matches the requested + name. + (get_syscalls_by_name): Rename from get_syscall_by_name. Now + accepts a reference to a vector of integers and returns a bool. + * xml-syscall.h (get_syscalls_by_name): Likewise. + 2018-11-09 John Baldwin * break-catch-syscall.c (catch_syscall_split_args): Pass 'result' diff --git a/gdb/NEWS b/gdb/NEWS index ff9b192a38..ff225f361e 100644 --- a/gdb/NEWS +++ b/gdb/NEWS @@ -38,6 +38,11 @@ requires the use of a keyword. Selecting a frame by level is unchanged. The MI comment "-stack-select-frame" is unchanged. +* System call catchpoints now support system call aliases. This is + used with the FreeBSD system call list so that system call + catchpoints will also trigger for legacy system call numbers used by + older FreeBSD binaries. + * New targets NXP S12Z s12z-*-elf diff --git a/gdb/break-catch-syscall.c b/gdb/break-catch-syscall.c index f3740a1673..61c667a261 100644 --- a/gdb/break-catch-syscall.c +++ b/gdb/break-catch-syscall.c @@ -419,18 +419,13 @@ 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); - - if (s.number == UNKNOWN_SYSCALL) + /* We have a name. Let's check if it's valid and fetch a + list of matching numbers. */ + if (!get_syscalls_by_name (gdbarch, cur_name, result)) /* 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); } } diff --git a/gdb/gdbarch.h b/gdb/gdbarch.h index 2cb6961083..8e354d2278 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 bbfa8d2205..ff0e751f48 100755 --- a/gdb/gdbarch.sh +++ b/gdb/gdbarch.sh @@ -1393,9 +1393,6 @@ done # close it off cat < diff --git a/gdb/xml-syscall.c b/gdb/xml-syscall.c index 664cee77dd..0e763045b4 100644 --- a/gdb/xml-syscall.c +++ b/gdb/xml-syscall.c @@ -61,13 +61,12 @@ 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) +bool +get_syscalls_by_name (struct gdbarch *gdbarch, const char *syscall_name, + std::vector &syscall_numbers) { syscall_warn_user (); - s->number = UNKNOWN_SYSCALL; - s->name = syscall_name; + return false; } const char ** @@ -97,8 +96,8 @@ 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. */ @@ -108,6 +107,10 @@ struct syscall_desc /* The syscall name. */ std::string name; + + /* An optional alias. */ + + std::string alias; }; typedef std::unique_ptr syscall_desc_up; @@ -207,10 +210,11 @@ 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 != NULL ? alias : ""); syscalls_info->syscalls.emplace_back (sysdesc); @@ -235,6 +239,7 @@ 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) @@ -243,6 +248,8 @@ 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 @@ -251,7 +258,8 @@ 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); } @@ -259,6 +267,7 @@ 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 } }; @@ -390,21 +399,22 @@ 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 bool +xml_get_syscalls_by_name (struct gdbarch *gdbarch, const char *syscall_name, + std::vector &syscall_numbers) { struct syscalls_info *syscalls_info = gdbarch_syscalls_info (gdbarch); - if (syscalls_info == NULL - || syscall_name == NULL) - return UNKNOWN_SYSCALL; + bool found = false; + if (syscalls_info != NULL && syscall_name != NULL) + for (const syscall_desc_up &sysdesc : syscalls_info->syscalls) + if (sysdesc->name == syscall_name || sysdesc->alias == syscall_name) + { + syscall_numbers.push_back (sysdesc->number); + found = true; + } - for (const syscall_desc_up &sysdesc : syscalls_info->syscalls) - if (sysdesc->name == syscall_name) - return sysdesc->number; - - return UNKNOWN_SYSCALL; + return found; } static const char * @@ -510,14 +520,13 @@ 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) +bool +get_syscalls_by_name (struct gdbarch *gdbarch, const char *syscall_name, + std::vector &syscall_numbers) { 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, syscall_numbers); } const char ** diff --git a/gdb/xml-syscall.h b/gdb/xml-syscall.h index 2e76a9a97f..a3b032aeb3 100644 --- a/gdb/xml-syscall.h +++ b/gdb/xml-syscall.h @@ -38,11 +38,13 @@ 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 numbers of all syscalls with either a name or + alias equal to SYSCALL_NAME are appended to SYSCALL_NUMBERS. If no + matching syscalls are found, return false. */ -void get_syscall_by_name (struct gdbarch *gdbarch, - const char *syscall_name, struct syscall *s); +bool get_syscalls_by_name (struct gdbarch *gdbarch, const char *syscall_name, + std::vector &syscall_numbers); /* 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