autoconf: Enhance the --enable-instrument-functions result output

It prints now, by default, also the static functions names.

To configure the printing of only the global functions names, as before:
$ make instrument_global

To go back to print all the functions names:
$ make instrument_all

In case of truncation, the indentation level is reset to its previous
level in pretty_print_packet().

[skip ci]

5 files changed, 91 insertions, 22 deletions

diff --git a/Makefile.in b/Makefile.in
index 2a3f695e..e93ee2d0 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -389,6 +389,13 @@ all: $(PROG)
 $(PROG): $(OBJ) @V_PCAPDEP@ $(LIBNETDISSECT)
 	@rm -f $@
 	$(CC) $(FULL_CFLAGS) $(LDFLAGS) -o $@ $(OBJ) $(LIBNETDISSECT) $(LIBS)
+	nm $(PROG) | grep ' [tT] ' > $(PROG)_instrument_functions.nm
+
+instrument_all: $(PROG)
+	nm $(PROG) | grep ' [tT] ' > $(PROG)_instrument_functions.nm
+
+instrument_global: $(PROG)
+	nm $(PROG) | grep ' [T] ' > $(PROG)_instrument_functions.nm
 
 $(LIBNETDISSECT): $(LIBNETDISSECT_OBJ)
 	@rm -f $@
diff --git a/configure b/configure
index 86a2b97d..4eaefa3c 100755
--- a/configure
+++ b/configure
@@ -4399,9 +4399,11 @@ $as_echo "yes" >&6; }
 $as_echo "#define ENABLE_INSTRUMENT_FUNCTIONS 1" >>confdefs.h
 
 	LOCALSRC="$LOCALSRC instrument-functions.c"
-	CFLAGS="$CFLAGS -finstrument-functions"
-	LDFLAGS="$LDFLAGS -Wl,--export-dynamic"
-	LIBS="$LIBS -ldl"
+	# Add '-finstrument-functions' instrumentation option to generate
+	# instrumentation calls for entry and exit to functions.
+	# Try to avoid Address Space Layout Randomization (ALSR).
+	CFLAGS="$CFLAGS -finstrument-functions -fno-stack-protector -fno-pic"
+	LDFLAGS="$LDFLAGS -fno-stack-protector -no-pie"
 	;;
 *)	{ $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
 $as_echo "no" >&6; }
diff --git a/configure.ac b/configure.ac
index 6d29d945..5ed2db91 100644
--- a/configure.ac
+++ b/configure.ac
@@ -157,9 +157,11 @@ yes)	AC_MSG_RESULT(yes)
 	AC_DEFINE(ENABLE_INSTRUMENT_FUNCTIONS, 1,
 	    [define if you want to build the instrument functions code])
 	LOCALSRC="$LOCALSRC instrument-functions.c"
-	CFLAGS="$CFLAGS -finstrument-functions"
-	LDFLAGS="$LDFLAGS -Wl,--export-dynamic"
-	LIBS="$LIBS -ldl"
+	# Add '-finstrument-functions' instrumentation option to generate
+	# instrumentation calls for entry and exit to functions.
+	# Try to avoid Address Space Layout Randomization (ALSR).
+	CFLAGS="$CFLAGS -finstrument-functions -fno-stack-protector -fno-pic"
+	LDFLAGS="$LDFLAGS -fno-stack-protector -no-pie"
 	;;
 *)	AC_MSG_RESULT(no)
 	;;
diff --git a/instrument-functions.c b/instrument-functions.c
index 39ec7627..bab32065 100644
--- a/instrument-functions.c
+++ b/instrument-functions.c
@@ -36,30 +36,82 @@ int profile_func_level = -1;
  * To instument a static function, remove temporarily the static specifier.
  */
 
-void __cyg_profile_func_enter(void *this_fn, void *call_site)
-			      __attribute__((no_instrument_function));
+#ifndef ND_NO_INSTRUMENT
+#define ND_NO_INSTRUMENT __attribute__((no_instrument_function))
+#endif
+
+void __cyg_profile_func_enter(void *this_fn, void *call_site) ND_NO_INSTRUMENT;
+
+void __cyg_profile_func_exit(void *this_fn, void *call_site) ND_NO_INSTRUMENT;
+
+/*
+ * Structure table to store the functions data from FILE_NAME.
+ * FILE_NAME is generated via:
+ * $ nm $(PROG) | grep ' [tT] '
+ * or
+ * $ nm $(PROG) | grep ' [T] '
+ */
 
-void __cyg_profile_func_exit(void *this_fn, void *call_site)
-			     __attribute__((no_instrument_function));
+#define MAX_FUNCTIONS 20000
+static struct {
+	void *addr;
+	char type;
+	char name[128];
+} functions[MAX_FUNCTIONS] ;
+static int functions_count;
+static int initialization_done;
 
 /*
- * The get_function_name() get the function name by calling dladdr()
+ * Read the result of nm in functions[]
  */
 
-static const char *get_function_name(void *func)
-			      __attribute__((no_instrument_function));
+#define FILE_NAME "tcpdump_instrument_functions.nm"
+
+void read_functions_table(void) ND_NO_INSTRUMENT;
+
+void
+read_functions_table(void)
+{
+	FILE *fp;
+	int i = 0;
+	if ((fp = fopen(FILE_NAME, "r")) == NULL) {
+	printf("Warning: Cannot open \"%s\" file\n", FILE_NAME);
+		return;
+	}
+	while (i < MAX_FUNCTIONS && fscanf(fp, "%p %c %s", &functions[i].addr,
+		      &functions[i].type, functions[i].name) != EOF)
+
+		i++;
+	fclose(fp);
+	functions_count = i;
+}
+
+/*
+ * Get the function name by searching in functions[]
+ */
+
+static const char * get_function_name(void *func) ND_NO_INSTRUMENT;
 
 static const char *
 get_function_name(void *func)
 {
-	Dl_info info;
-	const char *function_name;
-
-	if (dladdr(func, &info))
-		function_name = info.dli_sname;
+	int i = 0;
+	int found = 0;
+	if (!initialization_done) {
+		read_functions_table();
+		initialization_done = 1;
+	}
+	while (i < functions_count) {
+		if (functions[i].addr == func) {
+			found = 1;
+			break;
+		}
+		i++;
+	}
+	if (found)
+		return (functions[i].name);
 	else
-		function_name = NULL;
-	return function_name;
+		return NULL;
 }
 
 void
diff --git a/print.c b/print.c
index be487f66..b1c81dd6 100644
--- a/print.c
+++ b/print.c
@@ -310,6 +310,7 @@ get_if_printer(int type)
 
 #ifdef ENABLE_INSTRUMENT_FUNCTIONS
 extern int profile_func_level;
+static int pretty_print_packet_level = -1;
 #endif
 
 void
@@ -322,6 +323,11 @@ pretty_print_packet(netdissect_options *ndo, const struct pcap_pkthdr *h,
 	if (ndo->ndo_print_sampling && packets_captured % ndo->ndo_print_sampling != 0)
 		return;
 
+#ifdef ENABLE_INSTRUMENT_FUNCTIONS
+	if (pretty_print_packet_level == -1)
+		pretty_print_packet_level = profile_func_level;
+#endif
+
 	if (ndo->ndo_packet_number)
 		ND_PRINT("%5u  ", packets_captured);
 
@@ -411,8 +417,8 @@ pretty_print_packet(netdissect_options *ndo, const struct pcap_pkthdr *h,
 		/* Print the full packet */
 		ndo->ndo_ll_hdr_len = 0;
 #ifdef ENABLE_INSTRUMENT_FUNCTIONS
-		/* truncation => reassignment, currently: 1 (main is 0) */
-		profile_func_level = 1;
+		/* truncation => reassignment */
+		profile_func_level = pretty_print_packet_level;
 #endif
 		break;
 	}