From 090b412f77650ce13f822d621cf4b1356fa7c665 Mon Sep 17 00:00:00 2001 From: John Baldwin Date: Mon, 29 Jan 2018 23:43:04 +0000 Subject: [PATCH] MFC 327561: Report offset relative to the backing object for kinfo_vmentry structures. For the pathname reported in kinfo_vmentry structures (kve_path), the sysctl handlers walk the object chain to find the bottom-most VM object. This permits a COW mapping of a file with dirty pages to report the pathname of the originally mapped file. Do the same for the object offset (kve_offset) computing a cumulative offset during the same object walk so that the reported offset is relative to the reported pathname. Note that ptrace(PT_VM_ENTRY) already returns a cumulative offset rather than the raw offset of the VM map entry. Note also that this does not affect procstat -v output (even structured output) since that output does not include the kve_offset field. Sponsored by: DARPA / AFRL --- sys/kern/kern_proc.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/sys/kern/kern_proc.c b/sys/kern/kern_proc.c index 3f2325307332..840da54fe9fd 100644 --- a/sys/kern/kern_proc.c +++ b/sys/kern/kern_proc.c @@ -2061,8 +2061,10 @@ sysctl_kern_proc_ovmmap(SYSCTL_HANDLER_ARGS) } for (lobj = tobj = obj; tobj; tobj = tobj->backing_object) { - if (tobj != obj) + if (tobj != obj) { VM_OBJECT_RLOCK(tobj); + kve->kve_offset += tobj->backing_object_offset; + } if (lobj != obj) VM_OBJECT_RUNLOCK(lobj); lobj = tobj; @@ -2070,7 +2072,7 @@ sysctl_kern_proc_ovmmap(SYSCTL_HANDLER_ARGS) kve->kve_start = (void*)entry->start; kve->kve_end = (void*)entry->end; - kve->kve_offset = (off_t)entry->offset; + kve->kve_offset += (off_t)entry->offset; if (entry->protection & VM_PROT_READ) kve->kve_protection |= KVME_PROT_READ; @@ -2284,6 +2286,7 @@ kern_proc_vmmap_out(struct proc *p, struct sbuf *sb, ssize_t maxlen, int flags) for (tobj = obj; tobj != NULL; tobj = tobj->backing_object) { VM_OBJECT_RLOCK(tobj); + kve->kve_offset += tobj->backing_object_offset; lobj = tobj; } if (obj->backing_object == NULL) @@ -2302,7 +2305,7 @@ kern_proc_vmmap_out(struct proc *p, struct sbuf *sb, ssize_t maxlen, int flags) kve->kve_start = entry->start; kve->kve_end = entry->end; - kve->kve_offset = entry->offset; + kve->kve_offset += entry->offset; if (entry->protection & VM_PROT_READ) kve->kve_protection |= KVME_PROT_READ;