Author: pjd
Date: Wed Dec 19 23:59:48 2012
New Revision: 244452
URL: http://svnweb.freebsd.org/changeset/base/244452
Log:
Replace expand_name() function with corefile_open() function, which not
only returns name, but also vnode of corefile to use.
This simplifies the code and closes few races, especially in %I handling.
Reviewed by: kib
Obtained from: WHEEL Systems
Modified:
head/sys/kern/kern_sig.c
Modified: head/sys/kern/kern_sig.c
==============================================================================
--- head/sys/kern/kern_sig.c Wed Dec 19 23:40:02 2012 (r244451)
+++ head/sys/kern/kern_sig.c Wed Dec 19 23:59:48 2012 (r244452)
@@ -106,7 +106,6 @@ SDT_PROBE_ARGTYPE(proc, kernel, , signal
SDT_PROBE_ARGTYPE(proc, kernel, , signal_discard, 2, "int");
static int coredump(struct thread *);
-static char *expand_name(const char *, uid_t, pid_t, struct thread *, int);
static int killpg1(struct thread *td, int sig, int pgid, int all,
ksiginfo_t *ksi);
static int issignal(struct thread *td, int stop_allowed);
@@ -3034,8 +3033,9 @@ SYSCTL_STRING(_kern, OID_AUTO, corefile,
sizeof(corefilename), "Process corefile name format string");
/*
- * expand_name(name, uid, pid, td, compress)
- * Expand the name described in corefilename, using name, uid, and pid.
+ * 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.
* corefilename is a printf-like string, with three format specifiers:
* %N name of process ("name")
* %P process id (pid)
@@ -3044,15 +3044,15 @@ SYSCTL_STRING(_kern, OID_AUTO, corefile,
* by using "/dev/null", or all core files can be stored in "/cores/%U/%N-%P".
* This is controlled by the sysctl variable kern.corefile (see above).
*/
-static char *
-expand_name(const char *comm, uid_t uid, pid_t pid, struct thread *td,
- int compress)
+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;
const char *format;
- char *name;
- int i, indexpos;
- char *hostname;
+ char *hostname, *name;
+ int indexpos, i, error, cmode, flags, oflags;
hostname = NULL;
format = corefilename;
@@ -3110,11 +3110,14 @@ expand_name(const char *comm, uid_t uid,
"long\n", (long)pid, comm, (u_long)uid);
sbuf_delete(&sb);
free(name, M_TEMP);
- return (NULL);
+ return (ENOMEM);
}
sbuf_finish(&sb);
sbuf_delete(&sb);
+ cmode = S_IRUSR | S_IWUSR;
+ oflags = VN_OPEN_NOAUDIT | (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.
@@ -3122,18 +3125,10 @@ expand_name(const char *comm, uid_t uid,
* non-existing core file name to use.
*/
if (indexpos != -1) {
- struct nameidata nd;
- int cmode, flags, oflags, error;
-
- cmode = S_IRUSR | S_IWUSR;
- oflags = VN_OPEN_NOAUDIT |
- (capmode_coredump ? VN_OPEN_NOCAPCHECK : 0);
-
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);
+ NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_SYSSPACE, name, td);
error = vn_open_cred(&nd, &flags, cmode, oflags,
td->td_ucred, NULL);
if (error) {
@@ -3143,25 +3138,26 @@ expand_name(const char *comm, uid_t uid,
"pid %d (%s), uid (%u): Path `%s' failed "
"on initial open test, error = %d\n",
pid, comm, uid, name, error);
- free(name, M_TEMP);
- return (NULL);
- }
- NDFREE(&nd, NDF_ONLY_PNBUF);
- VOP_UNLOCK(nd.ni_vp, 0);
- error = vn_close(nd.ni_vp, FWRITE, td->td_ucred, td);
- if (error) {
- log(LOG_ERR,
- "pid %d (%s), uid (%u): Path `%s' failed "
- "on close after initial open test, "
- "error = %d\n",
- pid, comm, uid, name, error);
- free(name, M_TEMP);
- return (NULL);
}
- break;
+ goto out;
}
}
- return (name);
+
+ 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) {
+#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);
}
/*
@@ -3179,9 +3175,8 @@ coredump(struct thread *td)
struct ucred *cred = td->td_ucred;
struct vnode *vp;
struct flock lf;
- struct nameidata nd;
struct vattr vattr;
- int error, error1, flags, locked;
+ int error, error1, locked;
struct mount *mp;
char *name; /* name of corefile */
off_t limit;
@@ -3216,25 +3211,11 @@ coredump(struct thread *td)
}
PROC_UNLOCK(p);
- name = expand_name(p->p_comm, cred->cr_uid, p->p_pid, td, compress);
- if (name == NULL)
- return (EINVAL);
-
restart:
- NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_SYSSPACE, name, td);
- flags = O_CREAT | FWRITE | O_NOFOLLOW;
- error = vn_open_cred(&nd, &flags, S_IRUSR | S_IWUSR,
- VN_OPEN_NOAUDIT | (capmode_coredump ? VN_OPEN_NOCAPCHECK : 0),
- cred, NULL);
- if (error) {
-#ifdef AUDIT
- audit_proc_coredump(td, name, error);
-#endif
- free(name, M_TEMP);
+ error = corefile_open(p->p_comm, cred->cr_uid, p->p_pid, td, compress,
+ &vp, &name);
+ if (error != 0)
return (error);
- }
- NDFREE(&nd, NDF_ONLY_PNBUF);
- vp = nd.ni_vp;
/* Don't dump to non-regular files or files with links. */
if (vp->v_type != VREG || VOP_GETATTR(vp, &vattr, cred) != 0 ||
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