From 3c26c9d9597f982973b9b3a32364230096ab0d78 Mon Sep 17 00:00:00 2001 From: Mike Frysinger Date: Tue, 29 Jun 2010 15:05:17 -0700 Subject: [PATCH] nommu: add '[stack]' label to /proc/pid/maps output Add support to the NOMMU /proc/pid/maps file to show which mapping is the stack of the original thread after execve. This is largely based on the MMU code. Subsidiary thread stacks are not indicated. For FDPIC, we now get: root:/> cat /proc/self/maps 02064000-02067ccc rw-p 0004d000 00:01 22 /bin/busybox 0206e000-0206f35c rw-p 00006000 00:01 295 /lib/ld-uClibc.so.0 025f0000-025f6f0c r-xs 00000000 00:01 295 /lib/ld-uClibc.so.0 02680000-026ba6b0 r-xs 00000000 00:01 297 /lib/libc.so.0 02700000-0274d384 r-xs 00000000 00:01 22 /bin/busybox 02816000-02817000 rw-p 00000000 00:00 0 02848000-0284c0d8 rw-p 00000000 00:00 0 02860000-02880000 rw-p 00000000 00:00 0 [stack] The semi-downside here is that for FLAT, we get: root:/> cat /proc/155/maps 029f0000-029f9000 rwxp 00000000 00:00 0 [stack] The reason being that FLAT combines a whole lot of stuff into one map (including the stack). But this isn't any worse than the current output (which is nothing), so screw it. Signed-off-by: Mike Frysinger Signed-off-by: David Howells Cc: Greg Ungerer Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/proc/task_nommu.c | 20 ++++++++++++++++---- 1 file changed, 16 insertions(+), 4 deletions(-) diff --git a/fs/proc/task_nommu.c b/fs/proc/task_nommu.c index 46d4b5d72bd..cb6306e6384 100644 --- a/fs/proc/task_nommu.c +++ b/fs/proc/task_nommu.c @@ -122,11 +122,20 @@ int task_statm(struct mm_struct *mm, int *shared, int *text, return size; } +static void pad_len_spaces(struct seq_file *m, int len) +{ + len = 25 + sizeof(void*) * 6 - len; + if (len < 1) + len = 1; + seq_printf(m, "%*c", len, ' '); +} + /* * display a single VMA to a sequenced file */ static int nommu_vma_show(struct seq_file *m, struct vm_area_struct *vma) { + struct mm_struct *mm = vma->vm_mm; unsigned long ino = 0; struct file *file; dev_t dev = 0; @@ -155,11 +164,14 @@ static int nommu_vma_show(struct seq_file *m, struct vm_area_struct *vma) MAJOR(dev), MINOR(dev), ino, &len); if (file) { - len = 25 + sizeof(void *) * 6 - len; - if (len < 1) - len = 1; - seq_printf(m, "%*c", len, ' '); + pad_len_spaces(m, len); seq_path(m, &file->f_path, ""); + } else if (mm) { + if (vma->vm_start <= mm->start_stack && + vma->vm_end >= mm->start_stack) { + pad_len_spaces(m, len); + seq_puts(m, "[stack]"); + } } seq_putc(m, '\n'); -- 2.39.5