Provide mprotect syscall

sysdeps/nacl/irt_syscalls.c

Index: sysdeps/nacl/irt_syscalls.c
diff --git a/sysdeps/nacl/irt_syscalls.c b/sysdeps/nacl/irt_syscalls.c
index 14862fe333435d91dcba5ab87589f74d024dd27c..d4b5cd73501c517fbc5aa3dd2efcb37fc8b0f15d 100644
--- a/sysdeps/nacl/irt_syscalls.c
+++ b/sysdeps/nacl/irt_syscalls.c
@@ -269,6 +269,10 @@ static int nacl_irt_clock_gettime(clockid_t clk_id,
   return -NACL_SYSCALL (clock_gettime) (clk_id, tp);
 }
 
+static int nacl_irt_mprotect (void *addr, size_t len, int prot) {

[Mark Seaborn, 2013/03/29 15:48:07]

Nit: put this after munmap()

[Petr Hosek, 2013/03/29 21:02:21]

Moved.

+  return -NACL_SYSCALL (mprotect) (addr, len, prot);
+}
+
 static size_t no_interface (const char *interface_ident,
                             void *table, size_t tablesize) {
   return 0;
@@ -392,6 +396,8 @@ int (*__nacl_irt_open_resource) (const char* file, int *fd);
 int (*__nacl_irt_clock_getres) (clockid_t clk_id, struct timespec *res);
 int (*__nacl_irt_clock_gettime) (clockid_t clk_id, struct timespec *tp);
 
+int (*__nacl_irt_mprotect) (void *addr, size_t len, int prot);

[Mark Seaborn, 2013/03/29 15:48:07]

Put this after munmap() too

[Petr Hosek, 2013/03/29 21:02:21]

Moved.

+
 void
 init_irt_table (void)
 {
@@ -399,7 +405,7 @@ init_irt_table (void)
     struct nacl_irt_basic nacl_irt_basic;
     struct nacl_irt_fdio nacl_irt_fdio;
     struct nacl_irt_filename nacl_irt_filename;
-    struct nacl_irt_memory nacl_irt_memory;
+    struct nacl_irt_memory_v0_2 nacl_irt_memory;
     struct nacl_irt_dyncode nacl_irt_dyncode;
     struct nacl_irt_thread nacl_irt_thread;
     struct nacl_irt_mutex nacl_irt_mutex;
@@ -469,18 +475,30 @@ init_irt_table (void)
     }
 
   if (__nacl_irt_query &&
-      __nacl_irt_query (NACL_IRT_MEMORY_v0_1, &u.nacl_irt_memory,
+      __nacl_irt_query (NACL_IRT_MEMORY_v0_2, &u.nacl_irt_memory,
 		        sizeof(u.nacl_irt_memory)) == sizeof(u.nacl_irt_memory))
     {
       __nacl_irt_sysbrk = u.nacl_irt_memory.sysbrk;
       __nacl_irt_mmap = u.nacl_irt_memory.mmap;
       __nacl_irt_munmap = u.nacl_irt_memory.munmap;
+      __nacl_irt_mprotect = u.nacl_irt_memory.mprotect;
+    }
+  else if (__nacl_irt_query &&
+           __nacl_irt_query (NACL_IRT_MEMORY_v0_1, &u.nacl_irt_memory,
+                             sizeof(struct nacl_irt_memory_v0_1)) ==
+               sizeof(struct nacl_irt_memory_v0_1))
+    {
+      __nacl_irt_sysbrk = u.nacl_irt_memory.sysbrk;
+      __nacl_irt_mmap = u.nacl_irt_memory.mmap;
+      __nacl_irt_munmap = u.nacl_irt_memory.munmap;
+      __nacl_irt_mprotect = nacl_irt_mprotect;

[Mark Seaborn, 2013/03/29 15:48:07]

You shouldn't fall back to using the syscall directly if NACL_IRT_MEMORY_v0_2
isn't present.  You should fall back to a function that returns ENOSYS.

Falling back to direct syscalls should only happen if the IRT isn't present at
all (and this is deprecated anyway; we should remove this fallback code some
time).

[Petr Hosek, 2013/03/29 21:02:21]

Fixed.

     }
   else
     {
       __nacl_irt_sysbrk = nacl_irt_sysbrk;
       __nacl_irt_mmap = nacl_irt_mmap;
       __nacl_irt_munmap = nacl_irt_munmap;
+      __nacl_irt_mprotect = nacl_irt_mprotect;
     }
 
   if (__nacl_irt_query &&