Date: Wed, 7 Nov 2018 20:31:36 +0000 (UTC) From: Mariusz Zaborski <oshogbo@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-11@freebsd.org Subject: svn commit: r340237 - in stable/11: . sys/kern Message-ID: <201811072031.wA7KVa2o010047@repo.freebsd.org>
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Author: oshogbo Date: Wed Nov 7 20:31:36 2018 New Revision: 340237 URL: https://svnweb.freebsd.org/changeset/base/340237 Log: MFC r335844: core(5): overwrite the oldest core dump The '%I' format in the kern.corefile sysctl limits the number of core files that a process can generate to the number stored in the debug.ncores sysctl. The '%I' format is replaced by the single digit index. Previously, if all indexes were taken the kernel would overwrite only a core file with the highest index in a filename. Currently the system will create a new core file if there is a free index or if all slots are taken it will overwrite the oldest one. Reviewed by: kib(code), bcr (updating) Differential Revision: https://reviews.freebsd.org/D15991 Differential Revision: https://reviews.freebsd.org/D16084 Modified: stable/11/UPDATING stable/11/sys/kern/kern_sig.c Directory Properties: stable/11/ (props changed) Modified: stable/11/UPDATING ============================================================================== --- stable/11/UPDATING Wed Nov 7 19:31:48 2018 (r340236) +++ stable/11/UPDATING Wed Nov 7 20:31:36 2018 (r340237) @@ -16,6 +16,15 @@ from older versions of FreeBSD, try WITHOUT_CLANG and the tip of head, and then rebuild without this option. The bootstrap process from older version of current across the gcc/clang cutover is a bit fragile. +20181107: + The '%I' format in the kern.corefile sysctl limits the number of + core files that a process can generate to the number stored in the + debug.ncores sysctl. The '%I' format is replaced by the single digit + index. Previously, if all indexes were taken the kernel would overwrite + only a core file with the highest index in a filename. + Currently the system will create a new core file if there is a free + index or if all slots are taken it will overwrite the oldest one. + 20180818: WITH_OFED option now only enables the build for the OFED libraries and some fundamental client utilities. OpenSM and rest of the Modified: stable/11/sys/kern/kern_sig.c ============================================================================== --- stable/11/sys/kern/kern_sig.c Wed Nov 7 19:31:48 2018 (r340236) +++ stable/11/sys/kern/kern_sig.c Wed Nov 7 20:31:36 2018 (r340237) @@ -3304,7 +3304,89 @@ SYSCTL_PROC(_kern, OID_AUTO, corefile, CTLTYPE_STRING CTLFLAG_MPSAFE, 0, 0, sysctl_kern_corefile, "A", "Process corefile name format string"); +static void +vnode_close_locked(struct thread *td, struct vnode *vp) +{ + + VOP_UNLOCK(vp, 0); + vn_close(vp, FWRITE, td->td_ucred, td); +} + /* + * If the core format has a %I in it, then we need to check + * for existing corefiles before defining a name. + * To do this we iterate over 0..num_cores to find a + * non-existing core file name to use. If all core files are + * already used we choose the oldest one. + */ +static int +corefile_open_last(struct thread *td, char *name, int indexpos, + struct vnode **vpp) +{ + struct vnode *oldvp, *nextvp, *vp; + struct vattr vattr; + struct nameidata nd; + int error, i, flags, oflags, cmode; + struct timespec lasttime; + + nextvp = oldvp = NULL; + cmode = S_IRUSR | S_IWUSR; + oflags = VN_OPEN_NOAUDIT | VN_OPEN_NAMECACHE | + (capmode_coredump ? VN_OPEN_NOCAPCHECK : 0); + + for (i = 0; i < num_cores; i++) { + flags = O_CREAT | FWRITE | O_NOFOLLOW; + name[indexpos] = '0' + i; + + NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_SYSSPACE, name, td); + error = vn_open_cred(&nd, &flags, cmode, oflags, td->td_ucred, + NULL); + if (error != 0) + break; + + vp = nd.ni_vp; + NDFREE(&nd, NDF_ONLY_PNBUF); + if ((flags & O_CREAT) == O_CREAT) { + nextvp = vp; + break; + } + + error = VOP_GETATTR(vp, &vattr, td->td_ucred); + if (error != 0) { + vnode_close_locked(td, vp); + break; + } + + if (oldvp == NULL || + lasttime.tv_sec > vattr.va_mtime.tv_sec || + (lasttime.tv_sec == vattr.va_mtime.tv_sec && + lasttime.tv_nsec >= vattr.va_mtime.tv_nsec)) { + if (oldvp != NULL) + vnode_close_locked(td, oldvp); + oldvp = vp; + lasttime = vattr.va_mtime; + } else { + vnode_close_locked(td, vp); + } + } + + if (oldvp != NULL) { + if (nextvp == NULL) + nextvp = oldvp; + else + vnode_close_locked(td, oldvp); + } + if (error != 0) { + if (nextvp != NULL) + vnode_close_locked(td, oldvp); + } else { + *vpp = nextvp; + } + + return (error); +} + +/* * corefile_open(comm, uid, pid, td, compress, vpp, namep) * Expand the name described in corefilename, using name, uid, and pid * and open/create core file. @@ -3320,11 +3402,11 @@ static int corefile_open(const char *comm, uid_t uid, pid_t pid, struct thread *td, int compress, struct vnode **vpp, char **namep) { - struct nameidata nd; struct sbuf sb; + struct nameidata nd; const char *format; char *hostname, *name; - int indexpos, i, error, cmode, flags, oflags; + int cmode, error, flags, i, indexpos, oflags; hostname = NULL; format = corefilename; @@ -3388,48 +3470,36 @@ corefile_open(const char *comm, uid_t uid, pid_t pid, sbuf_finish(&sb); sbuf_delete(&sb); - cmode = S_IRUSR | S_IWUSR; - oflags = VN_OPEN_NOAUDIT | VN_OPEN_NAMECACHE | - (capmode_coredump ? VN_OPEN_NOCAPCHECK : 0); - - /* - * If the core format has a %I in it, then we need to check - * for existing corefiles before returning a name. - * To do this we iterate over 0..num_cores to find a - * non-existing core file name to use. - */ if (indexpos != -1) { - for (i = 0; i < num_cores; i++) { - flags = O_CREAT | O_EXCL | FWRITE | O_NOFOLLOW; - name[indexpos] = '0' + i; - NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_SYSSPACE, name, td); - error = vn_open_cred(&nd, &flags, cmode, oflags, - td->td_ucred, NULL); - if (error) { - if (error == EEXIST) - continue; - log(LOG_ERR, - "pid %d (%s), uid (%u): Path `%s' failed " - "on initial open test, error = %d\n", - pid, comm, uid, name, error); - } - goto out; + error = corefile_open_last(td, name, indexpos, vpp); + if (error != 0) { + log(LOG_ERR, + "pid %d (%s), uid (%u): Path `%s' failed " + "on initial open test, error = %d\n", + pid, comm, uid, name, error); } + } else { + cmode = S_IRUSR | S_IWUSR; + oflags = VN_OPEN_NOAUDIT | VN_OPEN_NAMECACHE | + (capmode_coredump ? VN_OPEN_NOCAPCHECK : 0); + flags = O_CREAT | FWRITE | O_NOFOLLOW; + + NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_SYSSPACE, name, td); + error = vn_open_cred(&nd, &flags, cmode, oflags, td->td_ucred, + NULL); + if (error == 0) { + *vpp = nd.ni_vp; + NDFREE(&nd, NDF_ONLY_PNBUF); + } } - flags = O_CREAT | FWRITE | O_NOFOLLOW; - NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_SYSSPACE, name, td); - error = vn_open_cred(&nd, &flags, cmode, oflags, td->td_ucred, NULL); -out: - if (error) { + if (error != 0) { #ifdef AUDIT audit_proc_coredump(td, name, error); #endif free(name, M_TEMP); return (error); } - NDFREE(&nd, NDF_ONLY_PNBUF); - *vpp = nd.ni_vp; *namep = name; return (0); }
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