[PATCH RFC v1 1/1] Initial support for Lua scripting
Victor Krapivensky
krapivenskiy.va at phystech.edu
Sat Jun 10 20:17:29 UTC 2017
* Makefile.am: Build with LuaJIT if configured so.
(strace_SOURCES): Add defs_reuse.h.
* configure.ac: Add new --with-luajit configure option.
* defs.h: Move code that needs to be fed to LuaJIT's FFI to...
* defs_reuse.h: ...new file.
* strace.c: Initial support for Lua scripting.
(init): New -l option (if built with Lua scripting support).
(luajit_next_sc, check_lua, luajit_init): New functions.
(main): run Lua script, if built with Lua scripting support and a script
was provided.
---
Makefile.am | 6 +++
configure.ac | 34 +++++++++++++
defs.h | 34 +------------
defs_reuse.h | 58 ++++++++++++++++++++++
strace.c | 160 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
5 files changed, 259 insertions(+), 33 deletions(-)
create mode 100644 defs_reuse.h
diff --git a/Makefile.am b/Makefile.am
index 3d6eba1e..a7c4bce6 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -100,6 +100,7 @@ strace_SOURCES = \
copy_file_range.c \
count.c \
defs.h \
+ defs_reuse.h \
desc.c \
dirent.c \
dirent64.c \
@@ -276,6 +277,11 @@ strace_LDFLAGS += $(libunwind_LDFLAGS)
strace_LDADD += $(libunwind_LIBS)
endif
+if USE_LUAJIT
+strace_CPPFLAGS += $(luajit_CFLAGS)
+strace_LDADD += $(luajit_LIBS)
+endif
+
@CODE_COVERAGE_RULES@
CODE_COVERAGE_BRANCH_COVERAGE = 1
CODE_COVERAGE_GENHTML_OPTIONS = $(CODE_COVERAGE_GENHTML_OPTIONS_DEFAULT) \
diff --git a/configure.ac b/configure.ac
index dc49d397..b853c294 100644
--- a/configure.ac
+++ b/configure.ac
@@ -715,6 +715,40 @@ AC_SUBST(dl_LIBS)
AC_PATH_PROG([PERL], [perl])
+dnl LuaJIT scripting support
+use_luajit=no
+force_luajit=no
+luajit_lib=luajit
+luajit_LIBS=
+luajit_CFLAGS=
+AC_ARG_WITH([luajit],
+ [AS_HELP_STRING([--with-luajit],
+ [build with LuaJIT scripting support])],
+ [case "${withval}" in
+ yes) force_luajit=yes ;;
+ check) ;;
+ *) luajit_lib="${withval}" ;;
+ esac],
+ [:]
+)
+AS_IF([test "x$luajit_lib" != xno],
+ [AS_IF([test "x$force_luajit" = xyes],
+ [PKG_CHECK_MODULES([luajit], [$luajit_lib], [use_luajit=yes])],
+ [PKG_CHECK_MODULES([luajit], [$luajit_lib], [use_luajit=yes], [:])]
+ )
+ ]
+)
+
+dnl enable LuaJIT
+AC_MSG_CHECKING([whether to enable Lua scripting])
+if test "x$use_luajit" = xyes; then
+ AC_DEFINE([USE_LUAJIT], 1, [Enable Lua scripting support])
+ AC_SUBST(luajit_LIBS)
+ AC_SUBST(luajit_CFLAGS)
+fi
+AM_CONDITIONAL([USE_LUAJIT], [test "x$use_luajit" = xyes])
+AC_MSG_RESULT([$use_luajit])
+
dnl stack trace with libunwind
libunwind_CPPFLAGS=
libunwind_LDFLAGS=
diff --git a/defs.h b/defs.h
index 6449bce9..01a8c125 100644
--- a/defs.h
+++ b/defs.h
@@ -208,39 +208,7 @@ struct inject_opts {
#define MAX_ERRNO_VALUE 4095
#define INJECT_OPTS_RVAL_DEFAULT (-(MAX_ERRNO_VALUE + 1))
-/* Trace Control Block */
-struct tcb {
- int flags; /* See below for TCB_ values */
- int pid; /* If 0, this tcb is free */
- int qual_flg; /* qual_flags[scno] or DEFAULT_QUAL_FLAGS + RAW */
- unsigned long u_error; /* Error code */
- kernel_ulong_t scno; /* System call number */
- kernel_ulong_t u_arg[MAX_ARGS]; /* System call arguments */
- kernel_long_t u_rval; /* Return value */
-#if SUPPORTED_PERSONALITIES > 1
- unsigned int currpers; /* Personality at the time of scno update */
-#endif
- int sys_func_rval; /* Syscall entry parser's return value */
- int curcol; /* Output column for this process */
- FILE *outf; /* Output file for this process */
- const char *auxstr; /* Auxiliary info from syscall (see RVAL_STR) */
- void *_priv_data; /* Private data for syscall decoding functions */
- void (*_free_priv_data)(void *); /* Callback for freeing priv_data */
- const struct_sysent *s_ent; /* sysent[scno] or dummy struct for bad scno */
- const struct_sysent *s_prev_ent; /* for "resuming interrupted SYSCALL" msg */
- struct inject_opts *inject_vec[SUPPORTED_PERSONALITIES];
- struct timeval stime; /* System time usage as of last process wait */
- struct timeval dtime; /* Delta for system time usage */
- struct timeval etime; /* Syscall entry time */
-
-#ifdef USE_LIBUNWIND
- struct UPT_info* libunwind_ui;
- struct mmap_cache_t* mmap_cache;
- unsigned int mmap_cache_size;
- unsigned int mmap_cache_generation;
- struct queue_t* queue;
-#endif
-};
+#include "defs_reuse.h"
/* TCB flags */
/* We have attached to this process, but did not see it stopping yet */
diff --git a/defs_reuse.h b/defs_reuse.h
new file mode 100644
index 00000000..a6a8f8ca
--- /dev/null
+++ b/defs_reuse.h
@@ -0,0 +1,58 @@
+#define STRINGIFY(...) #__VA_ARGS__
+#ifdef FFI_CDEF
+# define CONTENT(...) STRINGIFY(__VA_ARGS__)
+#else
+# define CONTENT(...) __VA_ARGS__
+#endif
+
+CONTENT(
+struct tcb {
+ int flags; /* See below for TCB_ values */
+ int pid; /* If 0, this tcb is free */
+ int qual_flg; /* qual_flags[scno] or DEFAULT_QUAL_FLAGS + RAW */
+ unsigned long u_error; /* Error code */
+ kernel_ulong_t scno; /* System call number */
+ kernel_ulong_t u_arg[MAX_ARGS]; /* System call arguments */
+ kernel_long_t u_rval; /* Return value */
+)
+
+#if SUPPORTED_PERSONALITIES > 1
+CONTENT(
+ unsigned int currpers; /* Personality at the time of scno update */
+)
+#endif
+
+#ifndef FFI_CDEF
+ int sys_func_rval; /* Syscall entry parser's return value */
+ int curcol; /* Output column for this process */
+ FILE *outf; /* Output file for this process */
+ const char *auxstr; /* Auxiliary info from syscall (see RVAL_STR) */
+ void *_priv_data; /* Private data for syscall decoding functions */
+ void (*_free_priv_data)(void *); /* Callback for freeing priv_data */
+ const struct_sysent *s_ent; /* sysent[scno] or dummy struct for bad scno */
+ const struct_sysent *s_prev_ent; /* for "resuming interrupted SYSCALL" msg */
+ struct inject_opts *inject_vec[SUPPORTED_PERSONALITIES];
+ struct timeval stime; /* System time usage as of last process wait */
+ struct timeval dtime; /* Delta for system time usage */
+ struct timeval etime; /* Syscall entry time */
+# ifdef USE_LIBUNWIND
+ struct UPT_info* libunwind_ui;
+ struct mmap_cache_t* mmap_cache;
+ unsigned int mmap_cache_size;
+ unsigned int mmap_cache_generation;
+ struct queue_t* queue;
+# endif
+#endif /* FFI_CDEF */
+
+CONTENT(};)
+
+#ifdef USE_LUAJIT
+CONTENT(
+struct strace_luajit_funcs {
+ struct tcb * (*next_sc)(void);
+};
+)
+#endif
+
+#undef STRINGIFY
+#undef CONTENT
diff --git a/strace.c b/strace.c
index 5a1bcff3..30004444 100644
--- a/strace.c
+++ b/strace.c
@@ -45,6 +45,11 @@
# include <sys/prctl.h>
#endif
#include <asm/unistd.h>
+#ifdef USE_LUAJIT
+# include <lua.h>
+# include <lualib.h>
+# include <lauxlib.h>
+#endif
#include "scno.h"
#include "ptrace.h"
@@ -166,6 +171,11 @@ static volatile sig_atomic_t interrupted;
static volatile int interrupted;
#endif
+#ifdef USE_LUAJIT
+static lua_State *L = NULL;
+static void luajit_init(const char *scriptfile);
+#endif
+
#ifndef HAVE_STRERROR
#if !HAVE_DECL_SYS_ERRLIST
@@ -216,6 +226,11 @@ Output format:\n\
-k obtain stack trace between each syscall (experimental)\n\
"
#endif
+#ifdef USE_LUAJIT
+"\
+ -l file run a Lua script from FILE\n\
+"
+#endif
"\
-o file send trace output to FILE instead of stderr\n\
-q suppress messages about attaching, detaching, etc.\n\
@@ -1645,6 +1660,9 @@ init(int argc, char *argv[])
#ifdef USE_LIBUNWIND
"k"
#endif
+#ifdef USE_LUAJIT
+ "l:"
+#endif
"D"
"a:e:o:O:p:s:S:u:E:P:I:")) != EOF) {
switch (c) {
@@ -1755,6 +1773,11 @@ init(int argc, char *argv[])
stack_trace_enabled = true;
break;
#endif
+#ifdef USE_LUAJIT
+ case 'l':
+ luajit_init(optarg);
+ break;
+#endif
case 'E':
if (putenv(optarg) < 0)
die_out_of_memory();
@@ -2637,6 +2660,137 @@ terminate(void)
exit(exit_code);
}
+#ifdef USE_LUAJIT
+static struct tcb *
+luajit_next_sc(void)
+{
+ static struct timeval tv = {};
+ static bool first = true;
+
+# define MBRESTART(res, sig) \
+ if ((res) >= 0 && ptrace_restart(PTRACE_SYSCALL, current_tcp, sig) < 0) { \
+ /* Note: ptrace_restart emitted error message */ \
+ exit_code = 1; \
+ terminate(); \
+ }
+
+ if (!first) {
+ unsigned int sig = 0;
+ int res;
+ if (entering(current_tcp)) {
+ res = syscall_entering_trace(current_tcp, &sig);
+ syscall_entering_finish(current_tcp, res);
+ } else {
+ res = syscall_exiting_trace(current_tcp, tv, 1);
+ syscall_exiting_finish(current_tcp);
+ }
+ MBRESTART(res, sig);
+ }
+ first = false;
+
+ while (1) {
+ int status;
+ siginfo_t si;
+ enum trace_event ret = next_event(&status, &si);
+ if (ret == TE_SYSCALL_STOP) {
+ unsigned int sig = 0;
+ int res;
+ if (entering(current_tcp)) {
+ res = syscall_entering_decode(current_tcp);
+ switch (res) {
+ case 0:
+ break;
+ case 1:
+ return current_tcp;
+ default:
+ res = syscall_entering_trace(current_tcp, &sig);
+ syscall_entering_finish(current_tcp, res);
+ }
+ } else {
+ res = syscall_exiting_decode(current_tcp, &tv);
+ switch (res) {
+ case 0:
+ break;
+ case 1:
+ return current_tcp;
+ default:
+ res = syscall_exiting_trace(current_tcp, tv, res);
+ syscall_exiting_finish(current_tcp);
+ }
+ }
+ MBRESTART(res, sig);
+ } else {
+ if (!dispatch_event(ret, &status, &si)) {
+ terminate();
+ }
+ }
+ }
+# undef MBRESTART
+}
+
+static void
+check_lua(int ret)
+{
+ if (ret == 0)
+ return;
+ const char *msg = lua_tostring(L, -1);
+ if (!msg)
+ msg = "(error object can't be converted to string)";
+ error_msg_and_die("lua: %s", msg);
+}
+
+static void
+luajit_init(const char *scriptfile)
+{
+ static struct strace_luajit_funcs funcs = {
+ .next_sc = luajit_next_sc,
+ };
+
+ if (L)
+ /* already initialized? */
+ error_msg_and_help("multiple -l arguments");
+
+ if (!(L = luaL_newstate()))
+ die_out_of_memory();
+
+ luaL_openlibs(L);
+ /* L: - */
+ check_lua(luaL_loadfile(L, scriptfile)); /* L: chunk */
+ lua_getglobal(L, "require"); /* L: chunk require */
+ lua_pushstring(L, "ffi"); /* L: chunk require "ffi" */
+ check_lua(lua_pcall(L, 1, 1, 0)); /* L: chunk ffi */
+ lua_getfield(L, -1, "cdef"); /* L: chunk ffi cdef */
+ luaL_Buffer b;
+ luaL_buffinit(L, &b); /* L: chunk ffi cdef ? */
+ {
+ char buf[128];
+ snprintf(buf, sizeof(buf),
+ "typedef int%zu_t kernel_long_t;"
+ "typedef uint%zu_t kernel_ulong_t;",
+ sizeof(kernel_long_t) * 8,
+ sizeof(kernel_ulong_t) * 8);
+ luaL_addstring(&b, buf); /* L: chunk ffi cdef ? */
+ }
+ luaL_addstring(&b,
+# define FFI_CDEF
+# include "defs_reuse.h"
+# undef FFI_CDEF
+ ); /* L: chunk ffi cdef ? */
+ luaL_pushresult(&b); /* L: chunk ffi cdef str */
+ check_lua(lua_pcall(L, 1, 0, 0)); /* L: chunk ffi */
+ lua_newtable(L); /* L: chunk ffi table */
+ lua_getfield(L, -2, "cast"); /* L: chunk ffi table cast */
+ lua_pushstring(L, "struct strace_luajit_funcs *"); /* L: chunk ffi table cast str */
+ lua_pushlightuserdata(L, &funcs); /* L: chunk ffi table cast str lightuserdata */
+ check_lua(lua_pcall(L, 2, 1, 0)); /* L: chunk ffi table funcs */
+ lua_getfield(L, -1, "next_sc"); /* L: chunk ffi table funcs next_sc */
+ lua_setfield(L, -3, "next_sc"); /* L: chunk ffi table funcs */
+ lua_pop(L, 1); /* L: chunk ffi table */
+ lua_setglobal(L, "strace"); /* L: chunk ffi */
+ lua_pop(L, 1); /* L: chunk */
+}
+#endif /* USE_LUAJIT */
+
int
main(int argc, char *argv[])
{
@@ -2644,6 +2798,12 @@ main(int argc, char *argv[])
exit_code = !nprocs;
+#ifdef USE_LUAJIT
+ if (L) {
+ /* L: chunk */
+ check_lua(lua_pcall(L, 0, 0, 0)); /* L: - */
+ }
+#endif
int status;
siginfo_t si;
while (dispatch_event(next_event(&status, &si), &status, &si))
--
2.11.0
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