Add --enable-malloc-replacement option, for using libumem as a malloc replacement

.cvsignore

@@ -18,6 +18,7 @@ stamp-h.in
 stamp-h1
 umem_test
 umem_test2
+umem_test3
 Doxyfile
 umem.spec
 *.tar.gz

Makefile.am

@@ -1,13 +1,18 @@
-EXTRA_DIST = COPYRIGHT OPENSOLARIS.LICENSE umem.spec Doxyfile
+EXTRA_DIST = COPYRIGHT OPENSOLARIS.LICENSE umem.spec Doxyfile umem_test4
 
 lib_LTLIBRARIES = libumem.la
-noinst_PROGRAMS = umem_test umem_test2
+noinst_PROGRAMS = umem_test umem_test2 umem_test3
+
+libumem_la_LDFLAGS = -lpthread -ldl
 
 umem_test_SOURCES = umem_test.c
-umem_test_LDADD = -lumem -lpthread -ldl
+umem_test_LDADD = -lumem
 
 umem_test2_SOURCES = umem_test2.c
-umem_test2_LDADD = -lumem -lpthread -ldl
+umem_test2_LDADD = -lumem
+
+umem_test3_SOURCES = umem_test3.c
+umem_test3_LDADD = -lumem
 
 libumem_la_SOURCES =	init_lib.c \
 			umem_agent_support.c \
@@ -32,9 +37,13 @@ libumem_la_SOURCES =	init_lib.c \
 			sys/vmem.h \
 			sys/vmem_impl_user.h
 
+if MALLOC_REPLACEMENT
+libumem_la_SOURCES += malloc.c
+endif
+
 nobase_include_HEADERS = umem.h sys/vmem.h
 
-TESTS = umem_test umem_test2
+TESTS = umem_test umem_test2 umem_test3 umem_test4
 
 html-local:
 	mkdir -p docs
@@ -47,10 +56,6 @@ clean-local:
 rpm:	dist-bzip2
 	rpmbuild -ta $(distdir).tar.bz2
 
-# malloc.c
-
-# XXX: Standalone version?
-# See <http://cvs.opensolaris.org/source/xref/on/usr/src/lib/libumem/Makefile.com>
-
 # XXX: Non-i386: SPARC asm. x86_64?
 # Convert this to GNU as format: i386_subr_sol.s
+# <http://cvs.opensolaris.org/source/xref/on/usr/src/lib/libumem/>

configure.ac

@@ -1,6 +1,16 @@
 AC_INIT([umem], [1.0], [], [umem])
 AM_INIT_AUTOMAKE([dist-bzip2])
 
+AC_ARG_ENABLE([malloc-replacement],
+              AS_HELP_STRING([--enable-malloc-replacement],
+                             [Include implementations of malloc/free/etc. in libumem (default is no)]),
+              [case "${enableval}" in
+                yes) malloc_replacement=true ;;
+                no)  malloc_replacement=false ;;
+                *) AC_MSG_ERROR(bad value ${enableval} for --enable-malloc-replacement) ;;
+              esac],[malloc_replacement=false])
+AM_CONDITIONAL(MALLOC_REPLACEMENT, test x$malloc_replacement = xtrue)
+
 AC_PROG_CC
 AM_PROG_AS
 AC_PROG_LIBTOOL

init_lib.c

@@ -44,6 +44,9 @@
 #include <dlfcn.h>
 #endif
 
+#include <fcntl.h>
+#include <string.h>
+
 void
 vmem_heap_init(void)
 {
@@ -89,7 +92,41 @@ umem_type_init(caddr_t start, size_t len, size_t pgsize)
 int
 umem_get_max_ncpus(void)
 {
-#ifdef _SC_NPROCESSORS_ONLN
+#ifdef linux
+  /*
+   * HACK: sysconf() will invoke malloc() on Linux as part of reading
+   * in /proc/stat. To avoid recursion in the malloc replacement
+   * version of libumem, read /proc/stat into a static buffer.
+   */
+  static char proc_stat[8192];
+  int fd;
+  int ncpus = 1;
+
+  fd = open("/proc/stat", O_RDONLY);
+  if (fd >= 0) {
+    const ssize_t n = read(fd, proc_stat, sizeof(proc_stat) - 1);
+    if (n >= 0) {
+      const char *cur;
+      const char *next;
+
+      proc_stat[n] = '\0';
+      cur = proc_stat;
+      while (*cur && (next = strstr(cur + 3, "cpu"))) {
+        cur = next;
+      }
+
+      if (*cur)
+        ncpus = atoi(cur + 3) + 1;
+    }
+
+    close(fd);
+  }
+
+  return ncpus;
+
+#else /* !linux */
+
+#if _SC_NPROCESSORS_ONLN
   return (2 * sysconf(_SC_NPROCESSORS_ONLN));
 #elif defined(_SC_NPROCESSORS_CONF)
   return (2 * sysconf(_SC_NPROCESSORS_CONF));
@@ -101,4 +138,6 @@ umem_get_max_ncpus(void)
   /* XXX: determine CPU count on other platforms */
   return (1);
 #endif
+
+#endif /* linux */
 }

malloc.c

@@ -414,3 +414,9 @@ realloc(void *buf_arg, size_t newsize)
 	free(buf_arg);
 	return (buf);
 }
+
+void __attribute__((constructor))
+__malloc_umem_init (void)
+{
+  umem_startup(NULL, 0, 0, NULL, NULL);
+}

umem.spec.in

@@ -16,6 +16,7 @@ BuildRequires:  doxygen
 BuildRequires:  gcc
 BuildRequires:  binutils
 BuildRequires:  make
+BuildRequires:  mktemp
 
 
 %description

umem_test.c

@@ -18,6 +18,6 @@ int main(int argc, char *argv[])
 
   umem_free(foo, 32);
 
-  return 0;
+  return EXIT_SUCCESS;
 }
 

umem_test3.c

@@ -0,0 +1,14 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+int
+main (void)
+{
+  char *p;
+
+  p = malloc(10);
+  free(p);
+
+  return EXIT_SUCCESS;
+}

umem_test4

@@ -0,0 +1,23 @@
+#!/bin/sh
+#
+# Check that LD_PRELOAD'ing libumem works. This is how it can be used
+# to replace malloc for any program.
+#
+
+FILE=Makefile.am
+TMPLOC=$(mktemp -d -t umem_test4.XXXXXX)
+trap 'rm -rf $TMPLOC' 1 2 15
+
+LD_PRELOAD=.libs/libumem.so /usr/bin/ldd /bin/ls >$TMPLOC/log 2>&1
+
+# Check we got the expected result
+ret=0
+grep -E '(symbol lookup error|undefined symbol)' $TMPLOC/log >/dev/null 2>&1
+if [ "$?" = "0" ]; then
+  # Matched = failed to load up libumem
+  ret=1
+fi
+
+rm -rf $TMPLOC
+
+exit $ret