Author: dougm Date: Sun Dec 8 22:33:51 2019 New Revision: 355538 URL: https://svnweb.freebsd.org/changeset/base/355538
Log: Define a vm_map method for user-space for advancing from a map entry to its successor in cases where examining a map entry requires a helper like kvm_read_all. Use that method, with kvm_read_all, to fix procstat_getfiles_kvm, which tries to find the successor now without using such a helper. This addresses a problem introduced by r355491. Reviewed by: markj (previous version) Discussed with: kib Differential Revision: https://reviews.freebsd.org/D22728 Modified: head/lib/libprocstat/libprocstat.c head/sys/vm/vm_map.h Modified: head/lib/libprocstat/libprocstat.c ============================================================================== --- head/lib/libprocstat/libprocstat.c Sun Dec 8 21:30:04 2019 (r355537) +++ head/lib/libprocstat/libprocstat.c Sun Dec 8 22:33:51 2019 (r355538) @@ -445,6 +445,15 @@ getctty(kvm_t *kd, struct kinfo_proc *kp) return (sess.s_ttyvp); } +static int +procstat_vm_map_reader(void *token, vm_map_entry_t addr, vm_map_entry_t dest) +{ + kvm_t *kd; + + kd = (kvm_t *)token; + return (kvm_read_all(kd, (unsigned long)addr, dest, sizeof(*dest))); +} + static struct filestat_list * procstat_getfiles_kvm(struct procstat *procstat, struct kinfo_proc *kp, int mmapped) { @@ -454,7 +463,6 @@ procstat_getfiles_kvm(struct procstat *procstat, struc struct vm_object object; struct vmspace vmspace; vm_map_entry_t entryp; - vm_map_t map; vm_object_t objp; struct vnode *vp; struct file **ofiles; @@ -615,17 +623,11 @@ do_mmapped: (void *)kp->ki_vmspace); goto exit; } - map = &vmspace.vm_map; - for (entryp = vm_map_entry_first(map); - entryp != &kp->ki_vmspace->vm_map.header; - entryp = vm_map_entry_succ(&vmentry)) { - if (!kvm_read_all(kd, (unsigned long)entryp, &vmentry, - sizeof(vmentry))) { - warnx("can't read vm_map_entry at %p", - (void *)entryp); - continue; - } + vmentry = vmspace.vm_map.header; + for (entryp = vm_map_entry_read_succ(kd, &vmentry, procstat_vm_map_reader); + entryp != NULL && entryp != &kp->ki_vmspace->vm_map.header; + entryp = vm_map_entry_read_succ(kd, &vmentry, procstat_vm_map_reader)) { if (vmentry.eflags & MAP_ENTRY_IS_SUB_MAP) continue; if ((objp = vmentry.object.vm_object) == NULL) @@ -660,6 +662,8 @@ do_mmapped: if (entry != NULL) STAILQ_INSERT_TAIL(head, entry, next); } + if (entryp == NULL) + warnx("can't read vm_map_entry"); } exit: return (head); Modified: head/sys/vm/vm_map.h ============================================================================== --- head/sys/vm/vm_map.h Sun Dec 8 21:30:04 2019 (r355537) +++ head/sys/vm/vm_map.h Sun Dec 8 22:33:51 2019 (r355538) @@ -402,6 +402,47 @@ long vmspace_resident_count(struct vmspace *vmspace); #define VM_MAP_WIRE_WRITE 4 /* Validate writable. */ +typedef int vm_map_entry_reader(void *token, vm_map_entry_t addr, + vm_map_entry_t dest); + +#ifndef _KERNEL +/* + * Find the successor of a map_entry, using a reader to dereference pointers. + * '*clone' is a copy of a vm_map entry. 'reader' is used to copy a map entry + * at some address into '*clone'. Change *clone to a copy of the next map + * entry, and return the address of that entry, or NULL if copying has failed. + * + * This function is made available to user-space code that needs to traverse + * map entries. + */ +static inline vm_map_entry_t +vm_map_entry_read_succ(void *token, struct vm_map_entry *const clone, + vm_map_entry_reader reader) +{ + vm_map_entry_t after, backup; + vm_offset_t start; + + after = clone->right; + start = clone->start; + if (!reader(token, after, clone)) + return (NULL); + backup = clone->left; + if (!reader(token, backup, clone)) + return (NULL); + if (clone->start > start) { + do { + after = backup; + backup = clone->left; + if (!reader(token, backup, clone)) + return (NULL); + } while (clone->start != start); + } + if (!reader(token, after, clone)) + return (NULL); + return (after); +} +#endif /* ! _KERNEL */ + static inline vm_map_entry_t vm_map_entry_first(vm_map_t map) { _______________________________________________ svn-src-head@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-head To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"
