X-Git-Url: https://git.tcpdump.org/tcpdump/blobdiff_plain/6d854639ea6702adc7fcb077361ae00d2229f875..HEAD:/instrument-functions.c

diff --git a/instrument-functions.c b/instrument-functions.c
index bab32065..ba0a56a5 100644
--- a/instrument-functions.c
+++ b/instrument-functions.c
@@ -11,15 +11,11 @@
  * FOR A PARTICULAR PURPOSE.
  */
 
-#ifndef _GNU_SOURCE
-#define _GNU_SOURCE
-#endif
-
 #include <stdio.h>
-#include <dlfcn.h>
-
-extern int profile_func_level;
-int profile_func_level = -1;
+#include <string.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <bfd.h>
 
 /*
  * Generate instrumentation calls for entry and exit to functions.
@@ -30,118 +26,225 @@ int profile_func_level = -1;
  * The attribute 'no_instrument_function' causes this instrumentation is
  * not done.
  *
- * These profiling functions print the function names with indentation
- * and call level.
+ * These profiling functions call print_debug(). This function prints the
+ * current function name with indentation and call level.
+ * If entering in a function it prints also the calling function name with
+ * file name and line number.
  *
- * To instument a static function, remove temporarily the static specifier.
+ * If the environment variable INSTRUMENT is
+ * unset or set to an empty string, print nothing, like with no instrumentation
+ * set to "all" or "a", print all the functions names
+ * set to "global" or "g", print only the global functions names
  */
 
-#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;
+/* Store the function call level, used also in pretty_print_packet() */
+extern int profile_func_level;
+int profile_func_level = -1;
 
-/*
- * Structure table to store the functions data from FILE_NAME.
- * FILE_NAME is generated via:
- * $ nm $(PROG) | grep ' [tT] '
- * or
- * $ nm $(PROG) | grep ' [T] '
- */
+typedef enum {
+	ENTER,
+	EXIT
+} action_type;
 
-#define MAX_FUNCTIONS 20000
-static struct {
-	void *addr;
-	char type;
-	char name[128];
-} functions[MAX_FUNCTIONS] ;
-static int functions_count;
-static int initialization_done;
+void __cyg_profile_func_enter(void *this_fn, void *call_site) ND_NO_INSTRUMENT;
 
-/*
- * Read the result of nm in functions[]
- */
+void __cyg_profile_func_exit(void *this_fn, void *call_site) ND_NO_INSTRUMENT;
 
-#define FILE_NAME "tcpdump_instrument_functions.nm"
+static void print_debug(void *this_fn, void *call_site, action_type action)
+	ND_NO_INSTRUMENT;
 
-void read_functions_table(void) ND_NO_INSTRUMENT;
+void
+__cyg_profile_func_enter(void *this_fn, void *call_site)
+{
+	print_debug(this_fn, call_site, ENTER);
+}
 
 void
-read_functions_table(void)
+__cyg_profile_func_exit(void *this_fn, void *call_site)
 {
-	FILE *fp;
-	int i = 0;
-	if ((fp = fopen(FILE_NAME, "r")) == NULL) {
-	printf("Warning: Cannot open \"%s\" file\n", FILE_NAME);
-		return;
+	print_debug(this_fn, call_site, EXIT);
+}
+
+static void print_debug(void *this_fn, void *call_site, action_type action)
+{
+	static bfd* abfd;
+	static asymbol **symtab;
+	static long symcount;
+	static asection *text;
+	static bfd_vma vma;
+	static int instrument_set;
+	static int instrument_off;
+	static int instrument_global;
+
+	if (!instrument_set) {
+		static char *instrument_type;
+
+		/* Get the configuration environment variable INSTRUMENT value if any */
+		instrument_type = getenv("INSTRUMENT");
+		/* unset or set to an empty string ? */
+		if (instrument_type == NULL ||
+			!strncmp(instrument_type, "", sizeof(""))) {
+			instrument_off = 1;
+		} else {
+			/* set to "global" or "g" ? */
+			if (!strncmp(instrument_type, "global", sizeof("global")) ||
+				!strncmp(instrument_type, "g", sizeof("g")))
+				instrument_global = 1;
+			else if (strncmp(instrument_type, "all", sizeof("all")) &&
+					 strncmp(instrument_type, "a", sizeof("a"))) {
+				fprintf(stderr, "INSTRUMENT can be only \"\", \"all\", \"a\", "
+						"\"global\" or \"g\".\n");
+				exit(1);
+			}
+		}
+		instrument_set = 1;
 	}
-	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;
-}
+	if (instrument_off)
+			return;
 
-/*
- * Get the function name by searching in functions[]
- */
+	/* If no errors, this block should be executed one time */
+	if (!abfd) {
+		char pgm_name[1024];
+		long symsize;
+
+		ssize_t ret = readlink("/proc/self/exe", pgm_name, sizeof(pgm_name));
+		if (ret == -1) {
+			perror("failed to find executable");
+			return;
+		}
+		if (ret == sizeof(pgm_name)) {
+			/* no space for the '\0' */
+			printf("truncation may have occurred\n");
+			return;
+		}
+		pgm_name[ret] = '\0';
 
-static const char * get_function_name(void *func) ND_NO_INSTRUMENT;
+		bfd_init();
 
-static const char *
-get_function_name(void *func)
-{
-	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;
+		abfd = bfd_openr(pgm_name, NULL);
+		if (!abfd) {
+			bfd_perror("bfd_openr");
+			return;
+		}
+
+		if (!bfd_check_format(abfd, bfd_object)) {
+			bfd_perror("bfd_check_format");
+			return;
+		}
+
+		if((symsize = bfd_get_symtab_upper_bound(abfd)) == -1) {
+			bfd_perror("bfd_get_symtab_upper_bound");
+			return;
+		}
+
+		symtab = (asymbol **)malloc((size_t)symsize);
+		symcount = bfd_canonicalize_symtab(abfd, symtab);
+		if (symcount < 0) {
+			free(symtab);
+			bfd_perror("bfd_canonicalize_symtab");
+			return;
 		}
-		i++;
+
+		if ((text = bfd_get_section_by_name(abfd, ".text")) == NULL) {
+			bfd_perror("bfd_get_section_by_name");
+			return;
+		}
+		vma = text->vma;
 	}
-	if (found)
-		return (functions[i].name);
-	else
-		return NULL;
-}
 
-void
-__cyg_profile_func_enter(void *this_fn,
-			      void *call_site __attribute__((unused)))
-{
-	int i;
-	const char *function_name;
-
-	if ((function_name = get_function_name(this_fn)) != NULL) {
-		profile_func_level += 1;
-		for (i = 0 ; i < profile_func_level ; i++)
-			putchar(' ');
-		printf("[>> %s (%d)]\n", function_name, profile_func_level);
+	if (instrument_global) {
+		symbol_info syminfo;
+		int found;
+		long i;
+
+		i = 0;
+		found = 0;
+		while (i < symcount && !found) {
+			bfd_get_symbol_info(abfd, symtab[i], &syminfo);
+			if ((void *)syminfo.value == this_fn) {
+				found = 1;
+			}
+			i++;
+		}
+		/* type == 'T' for a global function */
+		if (found == 1 && syminfo.type != 'T')
+			return;
 	}
-	fflush(stdout);
-}
 
-void
-__cyg_profile_func_exit(void *this_fn,
-			     void *call_site __attribute__((unused)))
-{
-	int i;
-	const char *function_name;
-
-	if ((function_name = get_function_name(this_fn)) != NULL) {
-		for (i = 0 ; i < profile_func_level ; i++)
-			putchar(' ');
-		printf ("[<< %s (%d)]\n", function_name, profile_func_level);
-		profile_func_level -= 1;
+	/* Current function */
+	if ((bfd_vma)this_fn < vma) {
+		printf("[ERROR address this_fn]");
+	} else {
+		const char *file;
+		const char *func;
+		unsigned int line;
+
+		if (!bfd_find_nearest_line(abfd, text, symtab, (bfd_vma)this_fn - vma,
+								   &file, &func, &line)) {
+			printf("[ERROR bfd_find_nearest_line this_fn]");
+		} else {
+			int i;
+
+			if (action == ENTER)
+				profile_func_level += 1;
+			/* Indentation */
+			for (i = 0 ; i < profile_func_level ; i++)
+				putchar(' ');
+			if (action == ENTER)
+				printf("[>> ");
+			else
+				printf("[<< ");
+			/* Function name */
+			if (func == NULL || *func == '\0')
+				printf("???");
+			else
+				printf("%s", func);
+			printf(" (%d)", profile_func_level);
+			/* Print the "from" part except for the main function) */
+			if (action == ENTER && func != NULL &&
+				strncmp(func, "main", sizeof("main"))) {
+				/* Calling function */
+				if ((bfd_vma)call_site < vma) {
+					printf("[ERROR address call_site]");
+				} else {
+					if (!bfd_find_nearest_line(abfd, text, symtab,
+											   (bfd_vma)call_site - vma, &file,
+											   &func, &line)) {
+						printf("[ERROR bfd_find_nearest_line call_site]");
+					} else {
+						printf(" from ");
+						/* Function name */
+						if (func == NULL || *func == '\0')
+							printf("???");
+						else
+							printf("%s", func);
+						/* File name */
+						if (file == NULL || *file == '\0')
+							printf(" ??:");
+						else {
+							char *slashp = strrchr(file, '/');
+							if (slashp != NULL)
+								file = slashp + 1;
+							printf(" %s:", file);
+						}
+						/* Line number */
+						if (line == 0)
+							printf("?");
+						else
+							printf("%u", line);
+						printf("]");
+					}
+				}
+			}
+			putchar('\n');
+			if (action == EXIT)
+				profile_func_level -= 1;
+		}
 	}
 	fflush(stdout);
 }
+
+/* vi: set tabstop=4 softtabstop=0 shiftwidth=4 smarttab autoindent : */