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authorMatt Helsley <matthltc@us.ibm.com>2008-04-29 01:01:36 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2008-04-29 08:06:17 -0700
commit925d1c401fa6cfd0df5d2e37da8981494ccdec07 (patch)
tree4f3b7a09311cd99783b822350628125e44f9902d /fs/binfmt_flat.c
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 'fs/binfmt_flat.c')
-rw-r--r--fs/binfmt_flat.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/fs/binfmt_flat.c b/fs/binfmt_flat.c
index c12cc362fd3..3b40d45a3a1 100644
--- a/fs/binfmt_flat.c
+++ b/fs/binfmt_flat.c
@@ -531,7 +531,8 @@ static int load_flat_file(struct linux_binprm * bprm,
DBG_FLT("BINFMT_FLAT: ROM mapping of file (we hope)\n");
down_write(&current->mm->mmap_sem);
- textpos = do_mmap(bprm->file, 0, text_len, PROT_READ|PROT_EXEC, MAP_PRIVATE, 0);
+ textpos = do_mmap(bprm->file, 0, text_len, PROT_READ|PROT_EXEC,
+ MAP_PRIVATE|MAP_EXECUTABLE, 0);
up_write(&current->mm->mmap_sem);
if (!textpos || textpos >= (unsigned long) -4096) {
if (!textpos)