[patch] libkvm support

0001-Detect-and-use-libkvm.patch (text/plain), 6.25 KB, created by Alexis Ballier on 2010-04-26 18:42:06 UTC

From 2d318a3474088d0a741c3283a06ca906672fb400 Mon Sep 17 00:00:00 2001
From: Alexis Ballier <[e-mail]>
Date: Mon, 26 Apr 2010 20:38:52 +0200
Subject: [PATCH] Detect and use libkvm.

This gives support for grabbing the command line that triggered a violation on FreeBSD.
Also, check for struct reg to avoid #erroring for nothing; we do not have ptrace support in sandbox (yet).
---
 configure.ac            |   18 +++++++++++++++++-
 headers.h               |    9 +++++++++
 libsandbox/Makefile.am  |    2 +-
 libsandbox/libsandbox.c |   39 +++++++++++++++++++++++++++++++++++++++
 localdecls.h            |    2 ++
 5 files changed, 68 insertions(+), 2 deletions(-)

diff --git a/configure.ac b/configure.ac
index 86b2c3f..46d0502 100644
--- a/configure.ac
+++ b/configure.ac
@@ -74,6 +74,7 @@ AC_CHECK_HEADERS_ONCE([ \
 	execinfo.h \
 	fcntl.h \
 	grp.h \
+	kvm.h \
 	libgen.h \
 	limits.h \
 	memory.h \
@@ -101,10 +102,12 @@ AC_CHECK_HEADERS_ONCE([ \
 	sys/syscall.h \
 	sys/time.h \
 	sys/types.h \
+	sys/sysctl.h \
 	sys/user.h \
 	sys/wait.h \
 	asm/ptrace.h \
 	linux/ptrace.h \
+	machine/reg.h \
 ])
 
 dnl Checks for typedefs, structures, and compiler characteristics.
@@ -119,7 +122,7 @@ AC_CHECK_TYPES([sighandler_t, sig_t, __sighandler_t],,,[#include <signal.h>])
 
 save_CPPFLAGS=$CPPFLAGS
 CPPFLAGS="-I$srcdir $CPPFLAGS"
-AC_CHECK_TYPES([struct user_regs_struct, struct pt_regs],,,[#include "headers.h"])
+AC_CHECK_TYPES([struct user_regs_struct, struct pt_regs, struct reg],,,[#include "headers.h"])
 CPPFLAGS=$save_CPPFLAGS
 
 dnl Checks for library functions.
@@ -180,6 +183,19 @@ AC_CHECK_LIB([sigsegv], [stackoverflow_install_handler],
 	[HAVE_LIBSIGSEGV=false])
 AM_CONDITIONAL(HAVE_LIBSIGSEGV, $HAVE_LIBSIGSEGV)
 
+have_libkvm="no"
+AC_CHECK_LIB([kvm], [kvm_open],
+	[have_libkvm="yes"],
+	[have_libkvm="no"])
+LIBKVM=""
+if test "x$have_libkvm" = xyes ; then
+	AC_DEFINE([HAVE_LIBKVM], [1], [libkvm is available])
+	LIBKVM=-lkvm
+else
+	AC_DEFINE([HAVE_LIBKVM], [0], [libkvm is not available])
+fi
+AC_SUBST(LIBKVM)
+
 dnl Check for gcc atomic primitives
 AC_MSG_CHECKING([for __sync_lock_test_and_set])
 sltas=no
diff --git a/headers.h b/headers.h
index ab9c17d..a6b0010 100644
--- a/headers.h
+++ b/headers.h
@@ -32,6 +32,9 @@
 #ifdef HAVE_GRP_H
 # include <grp.h>
 #endif
+#ifdef HAVE_KVM_H
+# include <kvm.h>
+#endif
 #ifdef HAVE_LIBGEN_H
 # include <libgen.h>
 #endif
@@ -107,6 +110,9 @@
 #ifdef HAVE_SYS_SYSCALL_H
 # include <sys/syscall.h>
 #endif
+#ifdef HAVE_SYS_SYSCTL_H
+# include <sys/sysctl.h>
+#endif
 #ifdef HAVE_SYS_TIME_H
 # include <sys/time.h>
 #endif
@@ -119,6 +125,9 @@
 #ifdef HAVE_SYS_WAIT_H
 # include <sys/wait.h>
 #endif
+#ifdef HAVE_MACHINE_REG_H
+# include <machine/reg.h>
+#endif
 
 #ifdef __ia64__ /* what a pos */
 # define ia64_fpreg FU_ia64_fpreg
diff --git a/libsandbox/Makefile.am b/libsandbox/Makefile.am
index 9edd466..0485626 100644
--- a/libsandbox/Makefile.am
+++ b/libsandbox/Makefile.am
@@ -14,7 +14,7 @@ libsandbox_la_CFLAGS = $(CFLAG_EXCEPTIONS)
 #	$(top_builddir)/libsbutil/libsbutil.la
 libsandbox_la_LIBSBLIB = $(top_builddir)/libsbutil/.libs/libsbutil.a
 libsandbox_la_LIBADD = \
-	-lc $(LIBDL) \
+	-lc $(LIBDL) $(LIBKVM) \
 	$(libsandbox_la_LIBSBLIB)
 # Do not add -nostdlib or -nostartfiles, as then our constructor
 # and destructor will not be executed ...
diff --git a/libsandbox/libsandbox.c b/libsandbox/libsandbox.c
index fd3d2ea..aa4cf36 100644
--- a/libsandbox/libsandbox.c
+++ b/libsandbox/libsandbox.c
@@ -124,6 +124,7 @@ static const char *sb_get_fd_dir(void)
 #endif
 }
 
+#if !HAVE_LIBKVM
 static const char *sb_get_cmdline(pid_t pid)
 {
 #if !defined(SANDBOX_PROC_1_CMDLINE) && !defined(SANDBOX_PROC_SELF_CMDLINE) && !defined(SANDBOX_PROC_dd_CMDLINE)
@@ -135,6 +136,18 @@ static const char *sb_get_cmdline(pid_t pid)
 	sprintf(path, "/proc/%i/cmdline", pid);
 	return path;
 }
+#else /* !HAVE_LIBKVM */
+static char **sb_get_kvm_cmdline(pid_t pid)
+{
+	int cnt = 0;
+	char** ret;
+	kvm_t * kt = kvm_open(NULL, NULL, NULL, O_RDONLY, NULL);
+	struct kinfo_proc * proc = kvm_getprocs(kt, KERN_PROC_PID | KERN_PROC_ALL, ( pid ? pid : getpid() ), &cnt);
+	ret = ( cnt > 0 ? kvm_getargv(kt, proc, 0) : NULL);
+	kvm_close(kt);
+	return ret;
+}
+#endif /* !HAVE_LIBKVM */
 
 int canonicalize(const char *path, char *resolved_path)
 {
@@ -358,6 +371,7 @@ char *egetcwd(char *buf, size_t size)
 	return tmpbuf;
 }
 
+#if !HAVE_LIBKVM
 static int sb_copy_file_to_fd(const char *file, int ofd)
 {
 	int ret = -1;
@@ -388,6 +402,7 @@ static int sb_copy_file_to_fd(const char *file, int ofd)
 	free(buf);
 	return ret;
 }
+#endif /* !HAVE_LIBKVM */
 
 void sb_dump_backtrace(void)
 {
@@ -397,10 +412,21 @@ void sb_dump_backtrace(void)
 	num_funcs = backtrace(funcs, ARRAY_SIZE(funcs));
 	backtrace_symbols_fd(funcs, num_funcs, STDERR_FILENO);
 #endif
+#if !HAVE_LIBKVM
 	const char *cmdline = sb_get_cmdline(trace_pid);
 	sb_printf("%s: ", cmdline);
 	sb_copy_file_to_fd(cmdline, STDERR_FILENO);
 	sb_printf("\n\n");
+#else  /* !HAVE_LIBKVM */
+	char **cmdline = sb_get_kvm_cmdline(trace_pid);
+	if(cmdline) {
+		int i;
+		for(i=0;cmdline[i];i++)	sb_printf("%s ", cmdline[i]);
+		sb_printf("\n\n");
+	}
+	else
+		sb_printf("libkvm: unable to get cmdline\n\n");
+#endif /* !HAVE_LIBKVM */
 }
 
 __attribute__((noreturn))
@@ -492,11 +518,24 @@ static bool write_logfile(const char *logfile, const char *func, const char *pat
 	_SB_WRITE_STR(rpath);
 
 	_SB_WRITE_STR("\nC: ");
+#if !HAVE_LIBKVM
 	const char *cmdline = sb_get_cmdline(trace_pid);
 	if (sb_copy_file_to_fd(cmdline, logfd)) {
 		_SB_WRITE_STR("unable to read ");
 		_SB_WRITE_STR(cmdline);
 	}
+#else /* !HAVE_LIBKVM */
+	char **cmdline = sb_get_kvm_cmdline(trace_pid);
+	if(cmdline) {
+		int i;
+		for(i=0;cmdline[i];i++){
+			_SB_WRITE_STR(cmdline[i]);
+			_SB_WRITE_STR(" ");
+		}
+	}
+	else
+		_SB_WRITE_STR("unable to get cmdline from libkvm");
+#endif /* !HAVE_LIBKVM */
 	_SB_WRITE_STR("\n");
 
 	return true;
diff --git a/localdecls.h b/localdecls.h
index 83c01d6..206214f 100644
--- a/localdecls.h
+++ b/localdecls.h
@@ -67,6 +67,8 @@ typedef __sighandler_t sighandler_t;
 typedef struct pt_regs trace_regs;
 #elif defined(HAVE_STRUCT_USER_REGS_STRUCT)
 typedef struct user_regs_struct trace_regs;
+#elif defined(HAVE_STRUCT_REG)
+typedef struct reg trace_regs;
 #else
 # error "unable to find struct for tracing regs"
 #endif
-- 
1.7.0.4