Get rid of indirect include of fs_struct.h

[safe/jmp/linux-2.6] / fs / exec.c

diff --git a/fs/exec.c b/fs/exec.c
index 9881dc3..052a961 100644 (file)
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -53,6 +53,7 @@
 #include <linux/tracehook.h>
 #include <linux/kmod.h>
 #include <linux/fsnotify.h>
+#include <linux/fs_struct.h>
 
 #include <asm/uaccess.h>
 #include <asm/mmu_context.h>
@@ -1056,16 +1057,35 @@ EXPORT_SYMBOL(install_exec_creds);
  * - the caller must hold current->cred_exec_mutex to protect against
  *   PTRACE_ATTACH
  */
-void check_unsafe_exec(struct linux_binprm *bprm)
+int check_unsafe_exec(struct linux_binprm *bprm)
 {
-       struct task_struct *p = current;
+       struct task_struct *p = current, *t;
+       unsigned long flags;
+       unsigned n_fs;
+       int res = 0;
 
        bprm->unsafe = tracehook_unsafe_exec(p);
 
-       if (atomic_read(&p->fs->count) > 1 ||
-           atomic_read(&p->files->count) > 1 ||
-           atomic_read(&p->sighand->count) > 1)
+       n_fs = 1;
+       write_lock(&p->fs->lock);
+       lock_task_sighand(p, &flags);
+       for (t = next_thread(p); t != p; t = next_thread(t)) {
+               if (t->fs == p->fs)
+                       n_fs++;
+       }
+
+       if (p->fs->users > n_fs) {
                bprm->unsafe |= LSM_UNSAFE_SHARE;
+       } else {
+               if (p->fs->in_exec)
+                       res = -EAGAIN;
+               p->fs->in_exec = 1;
+       }
+
+       unlock_task_sighand(p, &flags);
+       write_unlock(&p->fs->lock);
+
+       return res;
 }
 
 /* 
@@ -1284,12 +1304,15 @@ int do_execve(char * filename,
        bprm->cred = prepare_exec_creds();
        if (!bprm->cred)
                goto out_unlock;
-       check_unsafe_exec(bprm);
+
+       retval = check_unsafe_exec(bprm);
+       if (retval)
+               goto out_unlock;
 
        file = open_exec(filename);
        retval = PTR_ERR(file);
        if (IS_ERR(file))
-               goto out_unlock;
+               goto out_unmark;
 
        sched_exec();
 
@@ -1332,6 +1355,9 @@ int do_execve(char * filename,
                goto out;
 
        /* execve succeeded */
+       write_lock(&current->fs->lock);
+       current->fs->in_exec = 0;
+       write_unlock(&current->fs->lock);
        current->in_execve = 0;
        mutex_unlock(&current->cred_exec_mutex);
        acct_update_integrals(current);
@@ -1350,6 +1376,11 @@ out_file:
                fput(bprm->file);
        }
 
+out_unmark:
+       write_lock(&current->fs->lock);
+       current->fs->in_exec = 0;
+       write_unlock(&current->fs->lock);
+
 out_unlock:
        current->in_execve = 0;
        mutex_unlock(&current->cred_exec_mutex);