bootstrap

diff --git a/.cvsignore b/.cvsignore
new file mode 100644 (file)
index 0000000..3934eaf
--- /dev/null
+++ b/.cvsignore
@@ -0,0 +1,2 @@
+libwayback.o
+libwayback.so

diff --git a/Makefile b/Makefile
new file mode 100644 (file)
index 0000000..7433b5d
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,13 @@
+CFLAGS=-ggdb3 -Wall -pedantic -ansi -D_GNU_SOURCE
+LDFLAGS=-shared -ldl
+
+all: libwayback.so
+
+libwayback.so: libwayback.o
+       $(CC) $(CFLAGS) $(CPPFLAGS) $(LDFLAGS) $(TARGET_ARCH) $^ $(OUTPUT_OPTION)
+
+libwayback.o: libwayback.c
+
+.PHONY: clean
+clean:
+       $(RM) libwayback.so *.o

diff --git a/README b/README
new file mode 100644 (file)
index 0000000..0e7cc9e
--- /dev/null
+++ b/README
@@ -0,0 +1,4 @@
+Use the following commands for settings system time back 23 days:
+
+export WAYBACK=$[23*24*60*60]
+export LD_PRELOAD="/absolute/path/to/libwayback.so:$LD_PRELOAD"

diff --git a/libvmtime.c b/libvmtime.c
new file mode 100644 (file)
index 0000000..164cb3c
--- /dev/null
+++ b/libvmtime.c
@@ -0,0 +1,116 @@
+#include <sys/time.h>
+#include <dlfcn.h>
+#include <sys/timeb.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <pthread.h>
+
+
+typedef int (*gettimeofday_func_t)(struct timeval *tv, struct timezone *tz);
+static gettimeofday_func_t gettimeofday_orig;
+
+typedef time_t (*time_func_t)(time_t *t);
+static time_func_t time_orig;
+
+typedef int (*ftime_func_t)(struct timeb *tp);
+static ftime_func_t ftime_orig;
+
+static time_t wayback=0;
+
+
+static int inside=0;
+static pthread_mutex_t inside_mutex=PTHREAD_RECURSIVE_MUTEX_INITIALIZER_NP;
+
+static void enter(void)
+{
+static int done=0;
+void *libc_handle;
+char *wayback_s;
+
+       if (pthread_mutex_lock(&inside_mutex)) {
+               fprintf(stderr,"libwayback: 'inside_mutex' lock fail!\n");
+               _exit(1);
+               }
+       if (inside<0) {
+               fprintf(stderr,"libwayback: 'inside' sanity fail!\n");
+               _exit(1);
+               }
+       if (inside) {
+               fprintf(stderr,"libwayback: looping!\n");
+               _exit(1);
+               }
+       inside++;
+
+       if (done)
+               return;
+       done=1;
+
+       if ((wayback_s=getenv("WAYBACK")))
+               wayback=atol(wayback_s);
+
+       libc_handle=dlopen("/lib/libc.so.6",RTLD_LAZY); /* RTLD_LAZY is mandatory */
+       gettimeofday_orig=(gettimeofday_func_t)dlsym(libc_handle,"gettimeofday");
+       time_orig=(time_func_t)dlsym(libc_handle,"time");
+       ftime_orig=(ftime_func_t)dlsym(libc_handle,"ftime");
+}
+
+static void leave(void)
+{
+       if (inside!=1) {
+               fprintf(stderr,"libwayback: 'inside' sanity fail!\n");
+               _exit(1);
+               }
+       inside--;
+       if (pthread_mutex_unlock(&inside_mutex)) {
+               fprintf(stderr,"libwayback: 'inside_mutex' unlock fail!\n");
+               _exit(1);
+               }
+}
+
+
+int gettimeofday(struct timeval *tv, struct timezone *tz)
+{
+int r;
+
+       enter();
+
+       r=(*gettimeofday_orig)(tv,tz);
+       if (tv)
+               tv->tv_sec-=wayback;
+
+       leave();
+
+       return r;
+}
+
+
+time_t time(time_t *t)
+{
+time_t r;
+
+       enter();
+       r=(*time_orig)(t);
+
+       if (t)
+               *t-=wayback;
+       r-=wayback;
+
+       leave();
+       return r;
+}
+
+
+int ftime(struct timeb *tp)
+{
+int r;
+
+       enter();
+       r=(*ftime_orig)(tp);
+       
+       if (tp)
+               tp->time-=wayback;
+
+       leave();
+       return r;
+}