Patch to sys_shmdt

From: Adam Bottchen (bottchen@earthlink.net)
Date: Thu Oct 11 2001 - 15:20:06 EST


        Currently sys_shmdt() always returns success. Below is a patch that changes
 this behavior to match the man page. This patch will cause sys_shmdt() to
return success only when it finds something to detach, and returns EINVAL
otherwise. The patch was run on a 2.4.10 kernel tree, but applies against a 2.4.12
tree with no problems.

--- linux-2.4.10old/ipc/shm.c Fri Oct 5 11:53:12 2001
+++ linux-2.4.10/ipc/shm.c Fri Oct 5 15:08:51 2001
@@ -649,16 +649,19 @@
 {
        struct mm_struct *mm = current->mm;
        struct vm_area_struct *shmd, *shmdnext;
+ int retcode=-EINVAL;

        down_write(&mm->mmap_sem);
        for (shmd = mm->mmap; shmd; shmd = shmdnext) {
                shmdnext = shmd->vm_next;
                if (shmd->vm_ops == &shm_vm_ops
- && shmd->vm_start - (shmd->vm_pgoff << PAGE_SHIFT) == (ulong) shmaddr)
+ && shmd->vm_start - (shmd->vm_pgoff << PAGE_SHIFT) == (ulong) shmaddr) {
                        do_munmap(mm, shmd->vm_start, shmd->vm_end - shmd->vm_start);
+ retcode=0;
+ }
        }
        up_write(&mm->mmap_sem);
- return 0;
+ return retcode;
 }

 #ifdef CONFIG_PROC_FS

Adam Bottchen
bottchen@earthlink.net
-
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