initial version of syscall-dump

Makefile

@@ -136,6 +136,14 @@ firmware/initramfs/root/modules_idl4k_7108_ST40HOST_LINUX_32BITS/axe_dmx.ko:
 	cd firmware ; ../tools/cpio-idl4k-bin.sh extract
 	chmod -R u+rw firmware/initramfs
 
+#
+# syscall dump
+#
+
+tools/syscall-dump: tools/syscall-dump.c
+	gcc -o syscall-dump.o -c -fPIC -Wall tools/syscall-dump.c
+	gcc -o syscall-dump.so -shared -rdynamic syscall-dump.o -ldl
+
 #
 # minisatip
 #

tools/syscall-dump.c

@@ -0,0 +1,213 @@
+/* 
+
+Compile:
+  gcc -o syscall-dump.o -c -fPIC -Wall syscall-dump.c
+  gcc -o syscall-dump.so -shared -rdynamic syscall-dump.o -ldl
+
+Usage:
+   export LD_PRELOAD=/tmp/syscall-dump.so
+   export SYSCALL_DUMP_LOG=/tmp/syscall.log
+   ..run.a.binary..
+
+*/
+
+#include <dlfcn.h>
+#include <sys/types.h>
+#include <sys/ioctl.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <stddef.h>
+#include <stdarg.h>
+#include <stdio.h>
+#include <errno.h>
+#include <string.h>
+#include <fcntl.h>
+
+#if defined(RTLD_NEXT)
+#define REAL_LIBC RTLD_NEXT
+#else
+#define REAL_LIBC ((void *) -1L)
+#endif
+
+/* Function pointers for real libc versions */
+static int dlog_fd = -1;
+static int (*real_open)(const char *pathname, int flags, ...);
+static int (*real_open64)(const char *pathname, int flags, ...);
+static int (*real_ioctl)(int fd, unsigned long request, ...);
+static ssize_t (*real_write)(int fd, const void *buf, size_t len);
+static ssize_t (*real_read)(int fd, void *buf, size_t len);
+static int (*real_close)(int fd);
+
+#define REDIR(realptr, symname) do { \
+  if ((realptr) == NULL) { \
+    (realptr) = dlsym(REAL_LIBC, symname); \
+    if ((realptr) == NULL) exit(1001); \
+  } \
+} while (0)
+
+#define E(r) (r < 0 ? errno : 0)
+
+/* log function */
+static void dlog(const char *fmt, ...)
+{
+  char buf[2048];
+  va_list ap;
+
+  if (dlog_fd < 0) {
+    const char *f = getenv("SYSCALL_DUMP_LOG");
+    REDIR(real_open, "open");
+    dlog_fd = f ? real_open(f, O_CREAT|O_APPEND|O_WRONLY, 0600) : 2 /* stderr */;
+    if (dlog_fd < 0) exit(1002);
+  }
+  va_start(ap, fmt);
+  vsnprintf(buf, sizeof(buf), fmt, ap);
+  va_end(ap);
+  REDIR(real_write, "write");
+  real_write(dlog_fd, buf, strlen(buf));
+}
+
+static void dlog_hexa(const char *prefix, void *buf, size_t len)
+{
+  char b[128];
+  size_t i, l;
+  
+  while (len > 0) {
+    for (i = l = 0; i < 16 && len > 0; i++, len--, buf++)
+      l += sprintf(b + l, "%s%02x", i > 0 ? ":" : "", *(unsigned char *)buf);
+    b[l] = '\n';
+    b[l+1] = '\0';
+    dlog("%s %s", prefix, b);
+  }
+}
+
+/* open() wrapper */
+int open(const char *pathname, int flags, ...)
+{
+  va_list ap;
+  mode_t mode;
+  int r;
+  
+  REDIR(real_open, "open");
+
+  if (flags & O_CREAT) {
+    /* Get argument */
+    va_start(ap, flags);
+    mode = va_arg(ap, mode_t);
+    va_end(ap);
+
+    r = real_open(pathname, flags, mode);
+    dlog("open('%s', 0x%x, 0x%lx) = %d (%d)\n", pathname, flags, (long)mode, r, E(r));
+  } else {
+    r = real_open(pathname, flags);
+    dlog("open('%s', 0x%x) = %d (%d)\n", pathname, flags, r, E(r));
+  }
+  return r;
+}
+
+/* open64() wrapper */
+int open64(const char *pathname, int flags, ...)
+{
+  va_list ap;
+  mode_t mode;
+  int r;
+  
+  REDIR(real_open64, "open64");
+
+  if (flags & O_CREAT) {
+    /* Get argument */
+    va_start(ap, flags);
+    mode = va_arg(ap, mode_t);
+    va_end(ap);
+
+    r = real_open64(pathname, flags, mode);
+    dlog("open64('%s', 0x%x, 0x%lx) = %d (%d)\n", pathname, flags, (long)mode, r, E(r));
+  } else {
+    r = real_open64(pathname, flags);
+    dlog("open64('%s', 0x%x) = %d (%d)\n", pathname, flags, r, E(r));
+  }
+  return r;
+}
+
+/* close() wrapper */
+int close(int fd)
+{
+  int r;
+
+  REDIR(real_close, "close");
+
+  r = real_close(fd);
+  dlog("close(%d) = %d (%d)\n", fd, r, E(r));
+  return r;
+}
+
+/* write() wrapper */
+ssize_t write(int fd, const void *buf, size_t len)
+{
+  int r;
+
+  REDIR(real_write, "write");
+  
+  r = real_write(fd, buf, len);
+  dlog("write(%d, %p, %zd) = %d (%d)\n", fd, buf, len, r, E(r));
+  return r;
+}
+
+/* read() wrapper */
+ssize_t read(int fd, void *buf, size_t len)
+{
+  int r;
+
+  REDIR(real_read, "read");
+  
+  r = real_read(fd, buf, len);
+  dlog("read(%d, %p, %zd) = %d (%d)\n", fd, buf, len, r, E(r));
+  if (r > 0)
+    dlog_hexa("  read:", buf, r);
+  return r;
+}
+
+/* ioctl() wrapper */
+int ioctl(int fd, unsigned long request, ...)
+{
+  va_list ap;
+  unsigned long size, dir, arg;
+  int r;
+
+  REDIR(real_ioctl, "ioctl");
+
+  /* Get argument */
+  va_start(ap, request);
+  arg = va_arg(ap, unsigned long);
+  va_end(ap);
+
+//  nr = (request >> _IOC_NRSHIFT) & _IOC_NRMASK;
+  size = (request >> _IOC_SIZESHIFT) & _IOC_SIZEMASK;
+//type = (request >> _IOC_TYPESHIFT) & _IOC_TYPEMASK;
+   dir = (request >> _IOC_DIRSHIFT) & _IOC_DIRMASK;
+
+  switch (dir) {
+  case _IOC_NONE:
+    r = real_ioctl(fd, request, arg);
+    dlog("ioctl(%d, 0x%04lx, 0x%08x) = %d (%d)\n", fd, request, arg, r, E(r));
+    break;
+  case _IOC_READ:
+    r = real_ioctl(fd, request, arg);
+    dlog("ioctl(%d, 0x%04lx, %p) = %d (%d)\n", fd, request, arg, r, E(r));
+    dlog_hexa("  ioctl()/r:", (void *)arg, size);
+    break;
+  case _IOC_WRITE:
+    dlog_hexa("ioctl()/w:", (void *)arg, size);
+    r = real_ioctl(fd, request, arg);
+    dlog("  ioctl(%d, 0x%04lx, %p) = %d (%d)\n", fd, request, arg, r, E(r));
+    break;
+  case _IOC_READ|_IOC_WRITE:
+    dlog_hexa("ioctl()/w:", (void *)arg, size);
+    r = real_ioctl(fd, request, arg);
+    dlog("  ioctl(%d, 0x%04lx, %p) = %d (%d)\n", fd, request, arg, r, E(r));
+    dlog_hexa("  ioctl()/r:", (void *)arg, size);
+    break;
+  }
+
+  return r;
+}