aboutsummaryrefslogtreecommitdiffstats
path: root/kernel
diff options
context:
space:
mode:
authorMatt Helsley <matthltc@us.ibm.com>2008-04-29 04:01:36 -0400
committerLinus Torvalds <torvalds@linux-foundation.org>2008-04-29 11:06:17 -0400
commit925d1c401fa6cfd0df5d2e37da8981494ccdec07 (patch)
tree4f3b7a09311cd99783b822350628125e44f9902d /kernel
parente93b4ea20adb20f1f1f07f10ba5d7dd739d2843e (diff)
procfs task exe symlink
The kernel implements readlink of /proc/pid/exe by getting the file from the first executable VMA. Then the path to the file is reconstructed and reported as the result. Because of the VMA walk the code is slightly different on nommu systems. This patch avoids separate /proc/pid/exe code on nommu systems. Instead of walking the VMAs to find the first executable file-backed VMA we store a reference to the exec'd file in the mm_struct. That reference would prevent the filesystem holding the executable file from being unmounted even after unmapping the VMAs. So we track the number of VM_EXECUTABLE VMAs and drop the new reference when the last one is unmapped. This avoids pinning the mounted filesystem. [akpm@linux-foundation.org: improve comments] [yamamoto@valinux.co.jp: fix dup_mmap] Signed-off-by: Matt Helsley <matthltc@us.ibm.com> Cc: Oleg Nesterov <oleg@tv-sign.ru> Cc: David Howells <dhowells@redhat.com> Cc:"Eric W. Biederman" <ebiederm@xmission.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Hugh Dickins <hugh@veritas.com> Signed-off-by: YAMAMOTO Takashi <yamamoto@valinux.co.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/fork.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/kernel/fork.c b/kernel/fork.c
index de5c16c6b6ec..068ffe007529 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -431,6 +431,7 @@ void mmput(struct mm_struct *mm)
431 if (atomic_dec_and_test(&mm->mm_users)) { 431 if (atomic_dec_and_test(&mm->mm_users)) {
432 exit_aio(mm); 432 exit_aio(mm);
433 exit_mmap(mm); 433 exit_mmap(mm);
434 set_mm_exe_file(mm, NULL);
434 if (!list_empty(&mm->mmlist)) { 435 if (!list_empty(&mm->mmlist)) {
435 spin_lock(&mmlist_lock); 436 spin_lock(&mmlist_lock);
436 list_del(&mm->mmlist); 437 list_del(&mm->mmlist);
@@ -543,6 +544,8 @@ struct mm_struct *dup_mm(struct task_struct *tsk)
543 if (init_new_context(tsk, mm)) 544 if (init_new_context(tsk, mm))
544 goto fail_nocontext; 545 goto fail_nocontext;
545 546
547 dup_mm_exe_file(oldmm, mm);
548
546 err = dup_mmap(mm, oldmm); 549 err = dup_mmap(mm, oldmm);
547 if (err) 550 if (err)
548 goto free_pt; 551 goto free_pt;