instrument functions: Use an environment variable instead of config files

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

The configuration with --enable-instrument-functions remains.

Note that before this change, the default was to print all functions.
Now it is to print nothing.

This allows to run:
$ INSTRUMENT=a ./tcpslice ...
$ INSTRUMENT=g ./tcpslice ...
$ INSTRUMENT= ./tcpslice ...
or
$ export INSTRUMENT=global
$ ./tcpslice ...

This also allows to run the statically compiled binary on another host
after copying it.

It is no longer necessary to modify the configuration with:
$ make instrument_all
$ make instrument_global
$ make instrument_off
(Targets removed.)

Update .gitignore and Makefile.in accordingly.

Moreover:
Reduce the scope of a variable.
Rename a variable.
Remove '\n' in the perror() call.
Remove 2 spaces in function calls (style).

diff --git a/.gitignore b/.gitignore
index b34316059b1a67b2a616bf71eb8272a857b7001e..383608a0dfffe769a35a4ca94e351e6ccc229a21 100644 (file)
--- a/.gitignore
+++ b/.gitignore
@@ -14,5 +14,3 @@
 /autom4te.cache/
 /*.o
 *~
-/instrument_functions_global.devel
-/instrument_functions_off.devel

diff --git a/Makefile.in b/Makefile.in
index b8bb333deb2ea9f3b05dfe221a1d1f814e2a9db1..988d0151de1ede959a7d0343e5ebdc26d874a748 100644 (file)
--- a/Makefile.in
+++ b/Makefile.in
@@ -121,18 +121,6 @@ $(PROG): $(OBJ) @V_PCAPDEP@
        @rm -f $@
        $(CC) $(FULL_CFLAGS) $(LDFLAGS) -o $@ $(OBJ) $(LIBS)
 
-instrument_all: $(PROG)
-       @rm -f instrument_functions_global.devel
-       @rm -f instrument_functions_off.devel
-
-instrument_global: $(PROG)
-       @touch instrument_functions_global.devel
-       @rm -f instrument_functions_off.devel
-
-instrument_off: $(PROG)
-       @touch instrument_functions_off.devel
-       @rm -f instrument_functions_global.devel
-
 install: all
        [ -d "$(DESTDIR)$(bindir)" ] || \
            (mkdir -p "$(DESTDIR)$(bindir)"; chmod 755 "$(DESTDIR)$(bindir)")

diff --git a/instrument-functions.c b/instrument-functions.c
index 323497729ac62761147cc96caaff7991e7fc23d1..350a1682a0326f9a058e2f7369ff5320dcc01ce1 100644 (file)
--- a/instrument-functions.c
+++ b/instrument-functions.c
@@ -14,8 +14,6 @@
 #include <stdio.h>
 #include <string.h>
 #include <stdlib.h>
-#include <sys/types.h>
-#include <sys/stat.h>
 #include <unistd.h>
 #include <bfd.h>
 
@@ -33,14 +31,10 @@
  * If entering in a function it prints also the calling function name with
  * file name and line number.
  *
- * To configure the printing of only the global functions names:
- * $ make instrument_global
- *
- * To go back to print all the functions names:
- * $ make instrument_all
- *
- * To print nothing, like with no instrumentation:
- * $ make instrument_off
+ * 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
  */
 
 #define ND_NO_INSTRUMENT __attribute__((no_instrument_function))
@@ -73,12 +67,6 @@ __cyg_profile_func_exit(void *this_fn, void *call_site)
        print_debug(this_fn, call_site, EXIT);
 }
 
-/* If this file exists, print only the global functions */
-#define ND_FILE_FLAG_GLOBAL "instrument_functions_global.devel"
-
-/* If this file exists, print nothing, like with no instrumentation */
-#define ND_FILE_FLAG_OFF "instrument_functions_off.devel"
-
 static void print_debug(void *this_fn, void *call_site, action_type action)
 {
        static bfd* abfd;
@@ -86,32 +74,45 @@ static void print_debug(void *this_fn, void *call_site, action_type action)
        static long symcount;
        static asection *text;
        static bfd_vma vma;
+       static char *instrument_type;
+       static int instrument_set;
        static int instrument_off;
-       static int print_only_global;
-       symbol_info syminfo;
-       struct stat statbuf;
+       static int instrument_global;
        int i;
 
-       if (!instrument_off) {
-               /* one-time test */
-               if (!stat(ND_FILE_FLAG_OFF, &statbuf)) {
+       if (!instrument_set) {
+               /* 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;
-                       return;
+               } 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);
+                       }
                }
-       } else
-               return;
+               instrument_set = 1;
+       }
+
+       if (instrument_off)
+                       return;
 
        /* If no errors, this block should be executed one time */
        if (!abfd) {
                char pgm_name[1024];
                long symsize;
 
-               if (!stat(ND_FILE_FLAG_GLOBAL, &statbuf))
-                       print_only_global = 1;
-
                ssize_t ret = readlink("/proc/self/exe", pgm_name, sizeof(pgm_name));
                if (ret == -1) {
-                       perror("failed to find executable\n");
+                       perror("failed to find executable");
                        return;
                }
                if (ret == sizeof(pgm_name)) {
@@ -142,8 +143,8 @@ static void print_debug(void *this_fn, void *call_site, action_type action)
                symtab = (asymbol **)malloc(symsize);
                symcount = bfd_canonicalize_symtab(abfd, symtab);
                if (symcount < 0) {
-                       free (symtab);
-                       bfd_perror ("bfd_canonicalize_symtab");
+                       free(symtab);
+                       bfd_perror("bfd_canonicalize_symtab");
                        return;
                }
 
@@ -154,7 +155,8 @@ static void print_debug(void *this_fn, void *call_site, action_type action)
                vma = text->vma;
        }
 
-       if (print_only_global) {
+       if (instrument_global) {
+               symbol_info syminfo;
                int found;
 
                i = 0;