/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
/***
This file is part of systemd.
Copyright 2013 Lennart Poettering
systemd is free software; you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
systemd is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with systemd; If not, see .
***/
#include
#include "util.h"
#include "cgroup-util.h"
#include "fileio.h"
#include "audit.h"
#include "bus-message.h"
#include "bus-util.h"
#include "time-util.h"
#include "strv.h"
#include "bus-creds.h"
enum {
CAP_OFFSET_INHERITABLE = 0,
CAP_OFFSET_PERMITTED = 1,
CAP_OFFSET_EFFECTIVE = 2,
CAP_OFFSET_BOUNDING = 3
};
void bus_creds_done(sd_bus_creds *c) {
assert(c);
/* For internal bus cred structures that are allocated by
* something else */
free(c->session);
free(c->unit);
free(c->user_unit);
free(c->slice);
strv_free(c->cmdline_array);
strv_free(c->well_known_names);
}
_public_ sd_bus_creds *sd_bus_creds_ref(sd_bus_creds *c) {
assert_return(c, NULL);
if (c->allocated) {
assert(c->n_ref > 0);
c->n_ref++;
} else {
sd_bus_message *m;
/* If this is an embedded creds structure, then
* forward ref counting to the message */
m = container_of(c, sd_bus_message, creds);
sd_bus_message_ref(m);
}
return c;
}
_public_ sd_bus_creds *sd_bus_creds_unref(sd_bus_creds *c) {
if (!c)
return NULL;
if (c->allocated) {
assert(c->n_ref > 0);
c->n_ref--;
if (c->n_ref == 0) {
bus_creds_done(c);
free(c->comm);
free(c->tid_comm);
free(c->exe);
free(c->cmdline);
free(c->cgroup);
free(c->capability);
free(c->label);
free(c->unique_name);
free(c);
}
} else {
sd_bus_message *m;
m = container_of(c, sd_bus_message, creds);
sd_bus_message_unref(m);
}
return NULL;
}
_public_ uint64_t sd_bus_creds_get_mask(sd_bus_creds *c) {
assert_return(c, 0);
return c->mask;
}
sd_bus_creds* bus_creds_new(void) {
sd_bus_creds *c;
c = new0(sd_bus_creds, 1);
if (!c)
return NULL;
c->allocated = true;
c->n_ref = 1;
return c;
}
_public_ int sd_bus_creds_new_from_pid(pid_t pid, uint64_t mask, sd_bus_creds **ret) {
sd_bus_creds *c;
int r;
assert_return(pid >= 0, -EINVAL);
assert_return(mask <= _SD_BUS_CREDS_ALL, -ENOTSUP);
assert_return(ret, -EINVAL);
if (pid == 0)
pid = getpid();
c = bus_creds_new();
if (!c)
return -ENOMEM;
r = bus_creds_add_more(c, mask, pid, 0);
if (r < 0) {
free(c);
return r;
}
/* Check if the process existed at all, in case we haven't
* figured that out already */
if (kill(pid, 0) < 0 && errno == ESRCH) {
sd_bus_creds_unref(c);
return -ESRCH;
}
*ret = c;
return 0;
}
_public_ int sd_bus_creds_get_uid(sd_bus_creds *c, uid_t *uid) {
assert_return(c, -EINVAL);
assert_return(uid, -EINVAL);
assert_return(c->mask & SD_BUS_CREDS_UID, -ENODATA);
*uid = c->uid;
return 0;
}
_public_ int sd_bus_creds_get_gid(sd_bus_creds *c, gid_t *gid) {
assert_return(c, -EINVAL);
assert_return(gid, -EINVAL);
assert_return(c->mask & SD_BUS_CREDS_UID, -ENODATA);
*gid = c->gid;
return 0;
}
_public_ int sd_bus_creds_get_pid(sd_bus_creds *c, pid_t *pid) {
assert_return(c, -EINVAL);
assert_return(pid, -EINVAL);
assert_return(c->mask & SD_BUS_CREDS_PID, -ENODATA);
assert(c->pid > 0);
*pid = c->pid;
return 0;
}
_public_ int sd_bus_creds_get_tid(sd_bus_creds *c, pid_t *tid) {
assert_return(c, -EINVAL);
assert_return(tid, -EINVAL);
assert_return(c->mask & SD_BUS_CREDS_TID, -ENODATA);
assert(c->tid > 0);
*tid = c->tid;
return 0;
}
_public_ int sd_bus_creds_get_pid_starttime(sd_bus_creds *c, uint64_t *usec) {
assert_return(c, -EINVAL);
assert_return(usec, -EINVAL);
assert_return(c->mask & SD_BUS_CREDS_PID_STARTTIME, -ENODATA);
assert(c->pid_starttime > 0);
*usec = c->pid_starttime;
return 0;
}
_public_ int sd_bus_creds_get_selinux_context(sd_bus_creds *c, const char **ret) {
assert_return(c, -EINVAL);
assert_return(c->mask & SD_BUS_CREDS_SELINUX_CONTEXT, -ENODATA);
assert(c->label);
*ret = c->label;
return 0;
}
_public_ int sd_bus_creds_get_comm(sd_bus_creds *c, const char **ret) {
assert_return(c, -EINVAL);
assert_return(ret, -EINVAL);
assert_return(c->mask & SD_BUS_CREDS_COMM, -ENODATA);
assert(c->comm);
*ret = c->comm;
return 0;
}
_public_ int sd_bus_creds_get_tid_comm(sd_bus_creds *c, const char **ret) {
assert_return(c, -EINVAL);
assert_return(ret, -EINVAL);
assert_return(c->mask & SD_BUS_CREDS_TID_COMM, -ENODATA);
assert(c->tid_comm);
*ret = c->tid_comm;
return 0;
}
_public_ int sd_bus_creds_get_exe(sd_bus_creds *c, const char **ret) {
assert_return(c, -EINVAL);
assert_return(ret, -EINVAL);
assert_return(c->mask & SD_BUS_CREDS_EXE, -ENODATA);
assert(c->exe);
*ret = c->exe;
return 0;
}
_public_ int sd_bus_creds_get_cgroup(sd_bus_creds *c, const char **ret) {
assert_return(c, -EINVAL);
assert_return(ret, -EINVAL);
assert_return(c->mask & SD_BUS_CREDS_CGROUP, -ENODATA);
assert(c->cgroup);
*ret = c->cgroup;
return 0;
}
_public_ int sd_bus_creds_get_unit(sd_bus_creds *c, const char **ret) {
int r;
assert_return(c, -EINVAL);
assert_return(ret, -EINVAL);
assert_return(c->mask & SD_BUS_CREDS_UNIT, -ENODATA);
assert(c->cgroup);
if (!c->unit) {
r = cg_path_get_unit(c->cgroup, (char**) &c->unit);
if (r < 0)
return r;
}
*ret = c->unit;
return 0;
}
_public_ int sd_bus_creds_get_user_unit(sd_bus_creds *c, const char **ret) {
int r;
assert_return(c, -EINVAL);
assert_return(ret, -EINVAL);
assert_return(c->mask & SD_BUS_CREDS_USER_UNIT, -ENODATA);
assert(c->cgroup);
if (!c->user_unit) {
r = cg_path_get_user_unit(c->cgroup, (char**) &c->user_unit);
if (r < 0)
return r;
}
*ret = c->user_unit;
return 0;
}
_public_ int sd_bus_creds_get_slice(sd_bus_creds *c, const char **ret) {
int r;
assert_return(c, -EINVAL);
assert_return(ret, -EINVAL);
assert_return(c->mask & SD_BUS_CREDS_SLICE, -ENODATA);
assert(c->cgroup);
if (!c->slice) {
r = cg_path_get_slice(c->cgroup, (char**) &c->slice);
if (r < 0)
return r;
}
*ret = c->slice;
return 0;
}
_public_ int sd_bus_creds_get_session(sd_bus_creds *c, const char **ret) {
int r;
assert_return(c, -EINVAL);
assert_return(ret, -EINVAL);
assert_return(c->mask & SD_BUS_CREDS_SESSION, -ENODATA);
assert(c->cgroup);
if (!c->session) {
r = cg_path_get_session(c->cgroup, (char**) &c->session);
if (r < 0)
return r;
}
*ret = c->session;
return 0;
}
_public_ int sd_bus_creds_get_owner_uid(sd_bus_creds *c, uid_t *uid) {
assert_return(c, -EINVAL);
assert_return(uid, -EINVAL);
assert_return(c->mask & SD_BUS_CREDS_OWNER_UID, -ENODATA);
assert(c->cgroup);
return cg_path_get_owner_uid(c->cgroup, uid);
}
_public_ int sd_bus_creds_get_cmdline(sd_bus_creds *c, char ***cmdline) {
assert_return(c, -EINVAL);
assert_return(c->cmdline, -ESRCH);
assert_return(c->mask & SD_BUS_CREDS_CMDLINE, -ENODATA);
assert(c->cmdline);
if (!c->cmdline_array) {
c->cmdline_array = strv_parse_nulstr(c->cmdline, c->cmdline_size);
if (!c->cmdline_array)
return -ENOMEM;
}
*cmdline = c->cmdline_array;
return 0;
}
_public_ int sd_bus_creds_get_audit_session_id(sd_bus_creds *c, uint32_t *sessionid) {
assert_return(c, -EINVAL);
assert_return(sessionid, -EINVAL);
assert_return(c->mask & SD_BUS_CREDS_AUDIT_SESSION_ID, -ENODATA);
*sessionid = c->audit_session_id;
return 0;
}
_public_ int sd_bus_creds_get_audit_login_uid(sd_bus_creds *c, uid_t *uid) {
assert_return(c, -EINVAL);
assert_return(uid, -EINVAL);
assert_return(c->mask & SD_BUS_CREDS_AUDIT_LOGIN_UID, -ENODATA);
*uid = c->audit_login_uid;
return 0;
}
_public_ int sd_bus_creds_get_unique_name(sd_bus_creds *c, const char **unique_name) {
assert_return(c, -EINVAL);
assert_return(unique_name, -EINVAL);
assert_return(c->mask & SD_BUS_CREDS_UNIQUE_NAME, -ENODATA);
*unique_name = c->unique_name;
return 0;
}
_public_ int sd_bus_creds_get_well_known_names(sd_bus_creds *c, char ***well_known_names) {
assert_return(c, -EINVAL);
assert_return(well_known_names, -EINVAL);
assert_return(c->mask & SD_BUS_CREDS_WELL_KNOWN_NAMES, -ENODATA);
*well_known_names = c->well_known_names;
return 0;
}
static int has_cap(sd_bus_creds *c, unsigned offset, int capability) {
size_t sz;
assert(c);
assert(c->capability);
sz = c->capability_size / 4;
if ((size_t) capability >= sz*8)
return 0;
return !!(c->capability[offset * sz + (capability / 8)] & (1 << (capability % 8)));
}
_public_ int sd_bus_creds_has_effective_cap(sd_bus_creds *c, int capability) {
assert_return(c, -EINVAL);
assert_return(capability >= 0, -EINVAL);
assert_return(c->mask & SD_BUS_CREDS_EFFECTIVE_CAPS, -ENODATA);
return has_cap(c, CAP_OFFSET_EFFECTIVE, capability);
}
_public_ int sd_bus_creds_has_permitted_cap(sd_bus_creds *c, int capability) {
assert_return(c, -EINVAL);
assert_return(capability >= 0, -EINVAL);
assert_return(c->mask & SD_BUS_CREDS_PERMITTED_CAPS, -ENODATA);
return has_cap(c, CAP_OFFSET_PERMITTED, capability);
}
_public_ int sd_bus_creds_has_inheritable_cap(sd_bus_creds *c, int capability) {
assert_return(c, -EINVAL);
assert_return(capability >= 0, -EINVAL);
assert_return(c->mask & SD_BUS_CREDS_INHERITABLE_CAPS, -ENODATA);
return has_cap(c, CAP_OFFSET_INHERITABLE, capability);
}
_public_ int sd_bus_creds_has_bounding_cap(sd_bus_creds *c, int capability) {
assert_return(c, -EINVAL);
assert_return(capability >= 0, -EINVAL);
assert_return(c->mask & SD_BUS_CREDS_BOUNDING_CAPS, -ENODATA);
return has_cap(c, CAP_OFFSET_BOUNDING, capability);
}
static int parse_caps(sd_bus_creds *c, unsigned offset, const char *p) {
size_t sz;
unsigned i;
assert(c);
assert(p);
p += strspn(p, WHITESPACE);
sz = strlen(p);
if (sz % 2 != 0)
return -EINVAL;
sz /= 2;
if (!c->capability) {
c->capability = new0(uint8_t, sz * 4);
if (!c->capability)
return -ENOMEM;
c->capability_size = sz * 4;
}
for (i = 0; i < sz; i ++) {
int x, y;
x = unhexchar(p[i*2]);
y = unhexchar(p[i*2+1]);
if (x < 0 || y < 0)
return -EINVAL;
c->capability[offset * sz + (sz - i - 1)] = (uint8_t) x << 4 | (uint8_t) y;
}
return 0;
}
int bus_creds_add_more(sd_bus_creds *c, uint64_t mask, pid_t pid, pid_t tid) {
uint64_t missing;
int r;
assert(c);
assert(c->allocated);
missing = mask & ~c->mask;
if (missing == 0)
return 0;
/* Try to retrieve PID from creds if it wasn't passed to us */
if (pid <= 0 && (c->mask & SD_BUS_CREDS_PID))
pid = c->pid;
if (tid <= 0 && (c->mask & SD_BUS_CREDS_TID))
tid = c->pid;
/* Without pid we cannot do much... */
if (pid <= 0)
return 0;
if (missing & (SD_BUS_CREDS_UID | SD_BUS_CREDS_GID |
SD_BUS_CREDS_EFFECTIVE_CAPS | SD_BUS_CREDS_INHERITABLE_CAPS |
SD_BUS_CREDS_PERMITTED_CAPS | SD_BUS_CREDS_BOUNDING_CAPS)) {
_cleanup_fclose_ FILE *f = NULL;
char line[LINE_MAX];
const char *p;
p = procfs_file_alloca(pid, "status");
f = fopen(p, "re");
if (!f)
return errno == ENOENT ? -ESRCH : -errno;
FOREACH_LINE(line, f, return -errno) {
truncate_nl(line);
if (missing & SD_BUS_CREDS_UID) {
p = startswith(line, "Uid:");
if (p) {
unsigned long uid;
p += strspn(p, WHITESPACE);
if (sscanf(p, "%lu", &uid) != 1)
return -EIO;
c->uid = (uid_t) uid;
c->mask |= SD_BUS_CREDS_UID;
continue;
}
}
if (missing & SD_BUS_CREDS_GID) {
p = startswith(line, "Gid:");
if (p) {
unsigned long gid;
p += strspn(p, WHITESPACE);
if (sscanf(p, "%lu", &gid) != 1)
return -EIO;
c->gid = (uid_t) gid;
c->mask |= SD_BUS_CREDS_GID;
continue;
}
}
if (missing & SD_BUS_CREDS_EFFECTIVE_CAPS) {
p = startswith(line, "CapEff:");
if (p) {
r = parse_caps(c, CAP_OFFSET_EFFECTIVE, p);
if (r < 0)
return r;
c->mask |= SD_BUS_CREDS_EFFECTIVE_CAPS;
continue;
}
}
if (missing & SD_BUS_CREDS_PERMITTED_CAPS) {
p = startswith(line, "CapPrm:");
if (p) {
r = parse_caps(c, CAP_OFFSET_PERMITTED, p);
if (r < 0)
return r;
c->mask |= SD_BUS_CREDS_PERMITTED_CAPS;
continue;
}
}
if (missing & SD_BUS_CREDS_INHERITABLE_CAPS) {
p = startswith(line, "CapInh:");
if (p) {
r = parse_caps(c, CAP_OFFSET_INHERITABLE, p);
if (r < 0)
return r;
c->mask |= SD_BUS_CREDS_INHERITABLE_CAPS;
continue;
}
}
if (missing & SD_BUS_CREDS_BOUNDING_CAPS) {
p = startswith(line, "CapBnd:");
if (p) {
r = parse_caps(c, CAP_OFFSET_BOUNDING, p);
if (r < 0)
return r;
c->mask |= SD_BUS_CREDS_BOUNDING_CAPS;
continue;
}
}
}
}
if (missing & (SD_BUS_CREDS_PID_STARTTIME)) {
unsigned long long st;
r = get_starttime_of_pid(pid, &st);
if (r < 0)
return r;
c->pid_starttime = ((usec_t) st * USEC_PER_SEC) / (usec_t) sysconf(_SC_CLK_TCK);
c->mask |= SD_BUS_CREDS_PID_STARTTIME;
}
if (missing & SD_BUS_CREDS_SELINUX_CONTEXT) {
const char *p;
p = procfs_file_alloca(pid, "attr/current");
r = read_one_line_file(p, &c->label);
if (r < 0 && r != -ENOENT && r != -EINVAL)
return r;
else if (r >= 0)
c->mask |= SD_BUS_CREDS_SELINUX_CONTEXT;
}
if (missing & SD_BUS_CREDS_COMM) {
r = get_process_comm(pid, &c->comm);
if (r < 0)
return r;
c->mask |= SD_BUS_CREDS_COMM;
}
if (missing & SD_BUS_CREDS_EXE) {
r = get_process_exe(pid, &c->exe);
if (r < 0)
return r;
c->mask |= SD_BUS_CREDS_EXE;
}
if (missing & SD_BUS_CREDS_CMDLINE) {
const char *p;
p = procfs_file_alloca(pid, "cmdline");
r = read_full_file(p, &c->cmdline, &c->cmdline_size);
if (r < 0)
return r;
if (c->cmdline_size == 0) {
free(c->cmdline);
c->cmdline = NULL;
} else
c->mask |= SD_BUS_CREDS_CMDLINE;
}
if (tid > 0 && (missing & SD_BUS_CREDS_TID_COMM)) {
_cleanup_free_ char *p = NULL;
if (asprintf(&p, "/proc/%lu/task/%lu/comm", (unsigned long) pid, (unsigned long) tid) < 0)
return -ENOMEM;
r = read_one_line_file(p, &c->tid_comm);
if (r < 0)
return r == -ENOENT ? -ESRCH : r;
c->mask |= SD_BUS_CREDS_TID_COMM;
}
if (missing & (SD_BUS_CREDS_CGROUP|SD_BUS_CREDS_UNIT|SD_BUS_CREDS_USER_UNIT|SD_BUS_CREDS_SLICE|SD_BUS_CREDS_SESSION|SD_BUS_CREDS_OWNER_UID)) {
r = cg_pid_get_path(NULL, pid, &c->cgroup);
if (r < 0)
return r;
c->mask |= missing & (SD_BUS_CREDS_CGROUP|SD_BUS_CREDS_UNIT|SD_BUS_CREDS_USER_UNIT|SD_BUS_CREDS_SLICE|SD_BUS_CREDS_SESSION|SD_BUS_CREDS_OWNER_UID);
}
if (missing & SD_BUS_CREDS_AUDIT_SESSION_ID) {
r = audit_session_from_pid(pid, &c->audit_session_id);
if (r < 0 && r != -ENOTSUP && r != -ENXIO && r != -ENOENT)
return r;
else if (r >= 0)
c->mask |= SD_BUS_CREDS_AUDIT_SESSION_ID;
}
if (missing & SD_BUS_CREDS_AUDIT_LOGIN_UID) {
r = audit_loginuid_from_pid(pid, &c->audit_login_uid);
if (r < 0 && r != -ENOTSUP && r != -ENXIO && r != -ENOENT)
return r;
else if (r >= 0)
c->mask |= SD_BUS_CREDS_AUDIT_LOGIN_UID;
}
return 0;
}
int bus_creds_extend_by_pid(sd_bus_creds *c, uint64_t mask, sd_bus_creds **ret) {
_cleanup_bus_creds_unref_ sd_bus_creds *n = NULL;
int r;
assert(c);
assert(ret);
if ((mask & ~c->mask) == 0) {
/* There's already all data we need. */
*ret = sd_bus_creds_ref(c);
return 0;
}
n = bus_creds_new();
if (!n)
return -ENOMEM;
/* Copy the original data over */
if (c->mask & mask & SD_BUS_CREDS_UID) {
n->uid = c->uid;
n->mask |= SD_BUS_CREDS_UID;
}
if (c->mask & mask & SD_BUS_CREDS_GID) {
n->gid = c->gid;
n->mask |= SD_BUS_CREDS_GID;
}
if (c->mask & mask & SD_BUS_CREDS_PID) {
n->pid = c->pid;
n->mask |= SD_BUS_CREDS_PID;
}
if (c->mask & mask & SD_BUS_CREDS_TID) {
n->tid = c->tid;
n->mask |= SD_BUS_CREDS_TID;
}
if (c->mask & mask & SD_BUS_CREDS_PID_STARTTIME) {
n->pid_starttime = c->pid_starttime;
n->mask |= SD_BUS_CREDS_PID_STARTTIME;
}
if (c->mask & mask & SD_BUS_CREDS_COMM) {
n->comm = strdup(c->comm);
if (!n->comm)
return -ENOMEM;
n->mask |= SD_BUS_CREDS_COMM;
}
if (c->mask & mask & SD_BUS_CREDS_TID_COMM) {
n->tid_comm = strdup(c->tid_comm);
if (!n->tid_comm)
return -ENOMEM;
n->mask |= SD_BUS_CREDS_TID_COMM;
}
if (c->mask & mask & SD_BUS_CREDS_EXE) {
n->exe = strdup(c->exe);
if (!n->exe)
return -ENOMEM;
n->mask |= SD_BUS_CREDS_EXE;
}
if (c->mask & mask & SD_BUS_CREDS_CMDLINE) {
n->cmdline = memdup(c->cmdline, c->cmdline_size);
if (!n->cmdline)
return -ENOMEM;
n->cmdline_size = c->cmdline_size;
n->mask |= SD_BUS_CREDS_CMDLINE;
}
if (c->mask & mask & (SD_BUS_CREDS_CGROUP|SD_BUS_CREDS_SESSION|SD_BUS_CREDS_UNIT|SD_BUS_CREDS_USER_UNIT|SD_BUS_CREDS_SLICE|SD_BUS_CREDS_OWNER_UID)) {
n->cgroup = strdup(c->cgroup);
if (!n->cgroup)
return -ENOMEM;
n->mask |= mask & (SD_BUS_CREDS_CGROUP|SD_BUS_CREDS_SESSION|SD_BUS_CREDS_UNIT|SD_BUS_CREDS_USER_UNIT|SD_BUS_CREDS_SLICE|SD_BUS_CREDS_OWNER_UID);
}
if (c->mask & mask & (SD_BUS_CREDS_EFFECTIVE_CAPS|SD_BUS_CREDS_PERMITTED_CAPS|SD_BUS_CREDS_INHERITABLE_CAPS|SD_BUS_CREDS_BOUNDING_CAPS)) {
n->capability = memdup(c->capability, c->capability_size);
if (!n->capability)
return -ENOMEM;
n->capability_size = c->capability_size;
n->mask |= c->mask & mask & (SD_BUS_CREDS_EFFECTIVE_CAPS|SD_BUS_CREDS_PERMITTED_CAPS|SD_BUS_CREDS_INHERITABLE_CAPS|SD_BUS_CREDS_BOUNDING_CAPS);
}
if (c->mask & mask & SD_BUS_CREDS_AUDIT_SESSION_ID) {
n->audit_session_id = c->audit_session_id;
n->mask |= SD_BUS_CREDS_AUDIT_SESSION_ID;
}
if (c->mask & mask & SD_BUS_CREDS_AUDIT_LOGIN_UID) {
n->audit_login_uid = c->audit_login_uid;
n->mask |= SD_BUS_CREDS_AUDIT_LOGIN_UID;
}
if (c->mask & mask & SD_BUS_CREDS_UNIQUE_NAME) {
n->unique_name = strdup(c->unique_name);
if (!n->unique_name)
return -ENOMEM;
}
if (c->mask & mask & SD_BUS_CREDS_WELL_KNOWN_NAMES) {
n->well_known_names = strv_copy(c->well_known_names);
if (!n->well_known_names)
return -ENOMEM;
}
/* Get more data */
r = bus_creds_add_more(n, mask,
c->mask & SD_BUS_CREDS_PID ? c->pid : 0,
c->mask & SD_BUS_CREDS_TID ? c->tid : 0);
if (r < 0)
return r;
*ret = n;
n = NULL;
return 0;
}