[NaCl SDK] nacl_io: Make IRT intercepts (and their test code) more robust.

native_client_sdk/src/libraries/nacl_io/kernel_wrap_glibc.cc

Index: native_client_sdk/src/libraries/nacl_io/kernel_wrap_glibc.cc
diff --git a/native_client_sdk/src/libraries/nacl_io/kernel_wrap_glibc.cc b/native_client_sdk/src/libraries/nacl_io/kernel_wrap_glibc.cc
index f895ffb0fee46d76c87053a7fd1ce587a84e191f..5c0a3b4c713faf47b17ec96af06f24f67dd040b8 100644
--- a/native_client_sdk/src/libraries/nacl_io/kernel_wrap_glibc.cc
+++ b/native_client_sdk/src/libraries/nacl_io/kernel_wrap_glibc.cc
@@ -23,6 +23,7 @@
 
 #include "nacl_io/kernel_intercept.h"
 #include "nacl_io/kernel_wrap_real.h"
+#include "nacl_io/log.h"
 #include "nacl_io/osmman.h"
 
 
@@ -147,21 +148,36 @@ EXTERN_C_BEGIN
 
 EXPAND_SYMBOL_LIST_OPERATION(DECLARE_REAL_PTR);
 
+// Most kernal intercept functions (ki_*) return -1 and set errno accordingly.

[binji, 2014/05/06 23:25:54]

nit: kernel

[Sam Clegg, 2014/05/07 00:29:03]

Done.

+// However the IRT wrappers are expected to return errno on failure. Here we
+// check that the ki_ function actually set errno and fall back to EIO if it
+// didn't.
+#define RTN_ERRNO_IF(cond) \
+  if (cond) { \
+    int rtn = errno; \
+    if (rtn == 0) rtn = EIO; \

[binji, 2014/05/06 23:25:54]

we should probably assert here, right?

[Sam Clegg, 2014/05/07 00:29:03]

Done.

+    return rtn; \
+  }
+
 int WRAP(chdir)(const char* pathname) {
-  return (ki_chdir(pathname)) ? errno : 0;
+  RTN_ERRNO_IF(ki_chdir(pathname) < 0);
+  return 0;
 }
 
 int WRAP(close)(int fd) {
-  return (ki_close(fd) < 0) ? errno : 0;
+  RTN_ERRNO_IF(ki_close(fd) < 0);
+  return 0;
 }
 
 int WRAP(dup)(int fd, int* newfd) NOTHROW {
   *newfd = ki_dup(fd);
-  return (*newfd < 0) ? errno : 0;
+  RTN_ERRNO_IF(*newfd < 0);
+  return 0;
 }
 
 int WRAP(dup2)(int fd, int newfd) NOTHROW {
-  return (ki_dup2(fd, newfd) < 0) ? errno : 0;
+  RTN_ERRNO_IF(ki_dup2(fd, newfd) < 0);
+  return 0;
 }
 
 void WRAP(exit)(int status) {
@@ -172,15 +188,13 @@ int WRAP(fstat)(int fd, struct nacl_abi_stat *nacl_buf) {
   struct stat buf;
   memset(&buf, 0, sizeof(struct stat));
   int res = ki_fstat(fd, &buf);
-  if (res < 0)
-    return errno;
+  RTN_ERRNO_IF(res < 0);
   stat_to_nacl_stat(&buf, nacl_buf);
   return 0;
 }
 
 int WRAP(getcwd)(char* buf, size_t size) {
-  if (ki_getcwd(buf, size) == NULL)
-    return errno;
+  RTN_ERRNO_IF(ki_getcwd(buf, size) == NULL);
   return 0;
 }
 
@@ -194,8 +208,7 @@ int WRAP(getdents)(int fd, dirent* nacl_buf, size_t nacl_count, size_t *nread) {
   int count;
 
   count = ki_getdents(fd, buf, nacl_count);
-  if (count < 0)
-    return errno;
+  RTN_ERRNO_IF(count < 0);
 
   while (offset < count) {
     dirent* d = (dirent*)(buf + offset);
@@ -215,7 +228,8 @@ int WRAP(getdents)(int fd, dirent* nacl_buf, size_t nacl_count, size_t *nread) {
 }
 
 int WRAP(mkdir)(const char* pathname, mode_t mode) {
-  return (ki_mkdir(pathname, mode)) ? errno : 0;
+  RTN_ERRNO_IF(ki_mkdir(pathname, mode) < 0);
+  return 0;
 }
 
 int WRAP(mmap)(void** addr, size_t length, int prot, int flags, int fd,
@@ -224,7 +238,8 @@ int WRAP(mmap)(void** addr, size_t length, int prot, int flags, int fd,
     return REAL(mmap)(addr, length, prot, flags, fd, offset);
 
   *addr = ki_mmap(*addr, length, prot, flags, fd, offset);
-  return *addr == (void*)-1 ? errno : 0;
+  RTN_ERRNO_IF(*addr == (void*)-1);
+  return 0;
 }
 
 int WRAP(munmap)(void* addr, size_t length) {
@@ -236,47 +251,52 @@ int WRAP(munmap)(void* addr, size_t length) {
 
 int WRAP(open)(const char* pathname, int oflag, mode_t cmode, int* newfd) {
   *newfd = ki_open(pathname, oflag);
-  return (*newfd < 0) ? errno : 0;
+  RTN_ERRNO_IF(*newfd < 0);
+  return 0;
 }
 
 int WRAP(open_resource)(const char* file, int* fd) {
   *fd = ki_open_resource(file);
-  return (*fd < 0) ? errno : 0;
+  RTN_ERRNO_IF(*fd < 0);
+  return 0;
 }
 
 int WRAP(poll)(struct pollfd *fds, nfds_t nfds, int timeout, int* count) {
   *count = ki_poll(fds, nfds, timeout);
-  return (*count < 0) ? errno : 0;
-
+  RTN_ERRNO_IF(*count < 0);
+  return 0;
 }
 
 int WRAP(read)(int fd, void *buf, size_t count, size_t *nread) {
   ssize_t signed_nread = ki_read(fd, buf, count);
   *nread = static_cast<size_t>(signed_nread);
-  return (signed_nread < 0) ? errno : 0;
+  RTN_ERRNO_IF(signed_nread < 0);
+  return 0;
 }
 
 int WRAP(rmdir)(const char* pathname) {
-  return (ki_rmdir(pathname) < 0) ? errno : 0;
+  RTN_ERRNO_IF(ki_rmdir(pathname) < 0);
+  return 0;
 }
 
 int WRAP(seek)(int fd, off_t offset, int whence, off_t* new_offset) {
   *new_offset = ki_lseek(fd, offset, whence);
-  return (*new_offset < 0) ? errno : 0;
+  RTN_ERRNO_IF(*new_offset < 0);
+  return 0;
 }
 
 int WRAP(select)(int nfds, fd_set* readfds, fd_set* writefds,
                  fd_set* exceptfds, struct timeval* timeout, int* count) {
   *count = ki_select(nfds, readfds, writefds, exceptfds, timeout);
-  return (*count < 0) ? errno : 0;
+  RTN_ERRNO_IF(*count < 0);
+  return errno;

[binji, 2014/05/06 23:29:52]

return 0

[Sam Clegg, 2014/05/07 00:29:03]

Done.

 }
 
 int WRAP(stat)(const char *pathname, struct nacl_abi_stat *nacl_buf) {
   struct stat buf;
   memset(&buf, 0, sizeof(struct stat));
   int res = ki_stat(pathname, &buf);
-  if (res < 0)
-    return errno;
+  RTN_ERRNO_IF(res < 0);
   stat_to_nacl_stat(&buf, nacl_buf);
   return 0;
 }
@@ -284,7 +304,8 @@ int WRAP(stat)(const char *pathname, struct nacl_abi_stat *nacl_buf) {
 int WRAP(write)(int fd, const void* buf, size_t count, size_t* nwrote) {
   ssize_t signed_nwrote = ki_write(fd, buf, count);
   *nwrote = static_cast<size_t>(signed_nwrote);
-  return (signed_nwrote < 0) ? errno : 0;
+  RTN_ERRNO_IF(signed_nwrote < 0);
+  return 0;
 }
 
 static void assign_real_pointers() {
@@ -403,6 +424,7 @@ int _real_write(int fd, const void *buf, size_t count, size_t *nwrote) {
 static bool s_wrapped = false;
 void kernel_wrap_init() {
   if (!s_wrapped) {
+    LOG_TRACE("kernel_wrap_init");
     assign_real_pointers();
     EXPAND_SYMBOL_LIST_OPERATION(USE_WRAP)
     s_wrapped = true;
@@ -411,6 +433,7 @@ void kernel_wrap_init() {
 
 void kernel_wrap_uninit() {
   if (s_wrapped) {
+    LOG_TRACE("kernel_wrap_uninit");
     EXPAND_SYMBOL_LIST_OPERATION(USE_REAL)
     s_wrapped = false;
   }