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rework systemd's own process environment handling/passing

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Stop importing non-sensical kernel-exported variables. All
parameters in the kernel command line are exported to the
initial environment of PID1, but suppressed if they are
recognized by kernel built-in code. The EFI booted kernel
will add further kernel-internal things which do not belong
into userspace.

The passed original environ data of the process is not touched
and preserved across re-execution, to allow external reading of
/proc/self/environ for process properties like container*=.
This commit is contained in:
Kay Sievers 2013-07-26 05:22:22 +02:00
parent 68fee104e6
commit e21fea24ae
8 changed files with 77 additions and 97 deletions
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15
man/systemd.xml
View File

@ -1113,16 +1113,11 @@
<term><varname>systemd.setenv=</varname></term>
<listitem><para>Takes a string
argument in the form
VARIABLE=VALUE. May be used to set
environment variables for the init
process and all its children at boot
time. May be used more than once to
set multiple variables. If the equal
sign and variable are missing it unsets
an environment variable which might be
passed in from the initial ram
disk.</para></listitem>
argument in the form VARIABLE=VALUE.
May be used to set default environment
variables to add to forked child processes.
May be used more than once to set multiple
variables.</para></listitem>
</varlistentry>
<varlistentry>

21
src/core/locale-setup.c
View File

@ -28,6 +28,7 @@
#include "macro.h"
#include "virt.h"
#include "fileio.h"
#include "strv.h"
enum {
/* We don't list LC_ALL here on purpose. People should be
@ -67,7 +68,8 @@ static const char * const variable_names[_VARIABLE_MAX] = {
[VARIABLE_LC_IDENTIFICATION] = "LC_IDENTIFICATION"
};
int locale_setup(void) {
int locale_setup(char ***environment) {
char **env;
char *variables[_VARIABLE_MAX] = {};
int r = 0, i;
@ -118,13 +120,16 @@ int locale_setup(void) {
}
for (i = 0; i < _VARIABLE_MAX; i++) {
if (variables[i]) {
if (setenv(variable_names[i], variables[i], 1) < 0) {
r = -errno;
goto finish;
}
} else
unsetenv(variable_names[i]);
if (!variables[i])
continue;
env = strv_appendf(*environment, "%s=%s", variable_names[i], variables[i]);
if (!env) {
r = -ENOMEM;
goto finish;
}
*environment = env;
}
r = 0;

2
src/core/locale-setup.h
View File

@ -21,4 +21,4 @@
along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/
int locale_setup(void);
int locale_setup(char ***environment);

71
src/core/main.c
View File

@ -64,7 +64,6 @@
#endif
#include "hostname-setup.h"
#include "machine-id-setup.h"
#include "locale-setup.h"
#include "selinux-setup.h"
#include "ima-setup.h"
#include "fileio.h"
@ -349,32 +348,21 @@ static int parse_proc_cmdline_word(const char *word) {
arg_default_std_error = r;
} else if (startswith(word, "systemd.setenv=")) {
_cleanup_free_ char *cenv = NULL;
char *eq;
int r;
cenv = strdup(word + 15);
if (!cenv)
return -ENOMEM;
eq = strchr(cenv, '=');
if (!eq) {
if (!env_name_is_valid(cenv))
log_warning("Environment variable name '%s' is not valid. Ignoring.", cenv);
else {
r = unsetenv(cenv);
if (r < 0)
log_warning("Unsetting environment variable '%s' failed, ignoring: %m", cenv);
}
} else {
if (!env_assignment_is_valid(cenv))
log_warning("Environment variable assignment '%s' is not valid. Ignoring.", cenv);
else {
*eq = 0;
r = setenv(cenv, eq + 1, 1);
if (r < 0)
log_warning("Setting environment variable '%s=%s' failed, ignoring: %m", cenv, eq + 1);
}
}
if (env_assignment_is_valid(cenv)) {
char **env;
env = strv_env_set(arg_default_environment, cenv);
if (env)
arg_default_environment = env;
else
log_warning("Setting environment variable '%s' failed, ignoring: %m", cenv);
} else
log_warning("Environment variable name '%s' is not valid. Ignoring.", cenv);
} else if (startswith(word, "systemd.") ||
(in_initrd() && startswith(word, "rd.systemd."))) {
@ -1445,42 +1433,7 @@ int main(int argc, char *argv[]) {
if (serialization)
assert_se(fdset_remove(fds, fileno(serialization)) >= 0);
/* Set up PATH unless it is already set */
setenv("PATH",
#ifdef HAVE_SPLIT_USR
"/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin",
#else
"/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin",
#endif
arg_running_as == SYSTEMD_SYSTEM);
if (arg_running_as == SYSTEMD_SYSTEM) {
/* Unset some environment variables passed in from the
* kernel that don't really make sense for us. */
unsetenv("HOME");
unsetenv("TERM");
/* When we are invoked by a shell, these might be set,
* but make little sense to pass on */
unsetenv("PWD");
unsetenv("SHLVL");
unsetenv("_");
/* When we are invoked by a chroot-like tool such as
* nspawn, these might be set, but make little sense
* to pass on */
unsetenv("USER");
unsetenv("LOGNAME");
/* We suppress the socket activation env vars, as
* we'll try to match *any* open fd to units if
* possible. */
unsetenv("LISTEN_FDS");
unsetenv("LISTEN_PID");
/* All other variables are left as is, so that clients
* can still read them via /proc/1/environ */
/* Become a session leader if we aren't one yet. */
setsid();
@ -1528,8 +1481,6 @@ int main(int argc, char *argv[]) {
log_debug(PACKAGE_STRING " running in user mode. (" SYSTEMD_FEATURES ")");
if (arg_running_as == SYSTEMD_SYSTEM && !skip_setup) {
locale_setup();
if (arg_show_status || plymouth_running())
status_welcome();
@ -1595,7 +1546,7 @@ int main(int argc, char *argv[]) {
manager_set_default_rlimits(m, arg_default_rlimit);
if (arg_default_environment)
manager_set_default_environment(m, arg_default_environment);
manager_environment_add(m, arg_default_environment);
manager_set_show_status(m, arg_show_status);

47
src/core/manager.c
View File

@ -55,6 +55,7 @@
#include "util.h"
#include "mkdir.h"
#include "ratelimit.h"
#include "locale-setup.h"
#include "mount-setup.h"
#include "unit-name.h"
#include "dbus-unit.h"
@ -454,22 +455,36 @@ static int manager_setup_signals(Manager *m) {
return 0;
}
static void manager_strip_environment(Manager *m) {
static int manager_default_environment(Manager *m) {
#ifdef HAVE_SPLIT_USR
const char *path = "PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin";
#else
const char *path = "PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin";
#endif
assert(m);
/* Remove variables from the inherited set that are part of
* the container interface:
* http://www.freedesktop.org/wiki/Software/systemd/ContainerInterface */
strv_remove_prefix(m->environment, "container=");
strv_remove_prefix(m->environment, "container_");
if (m->running_as == SYSTEMD_SYSTEM) {
/* The system manager always starts with a clean
* environment for its children. It does not import
* the kernel or the parents exported variables.
*
* The initial passed environ is untouched to keep
* /proc/self/environ valid; it is used for tagging
* the init process inside containers. */
m->environment = strv_new(path, NULL);
/* Remove variables from the inherited set that are part of
* the initrd interface:
* http://www.freedesktop.org/wiki/Software/systemd/InitrdInterface */
strv_remove_prefix(m->environment, "RD_");
/* Import locale variables LC_*= from configuration */
locale_setup(&m->environment);
} else
/* The user manager passes its own environment
* along to its children. */
m->environment = strv_copy(environ);
/* Drop invalid entries */
strv_env_clean(m->environment);
if (!m->environment)
return -ENOMEM;
return 0;
}
int manager_new(SystemdRunningAs running_as, bool reexecuting, Manager **_m) {
@ -505,12 +520,10 @@ int manager_new(SystemdRunningAs running_as, bool reexecuting, Manager **_m) {
m->epoll_fd = m->dev_autofs_fd = -1;
m->current_job_id = 1; /* start as id #1, so that we can leave #0 around as "null-like" value */
m->environment = strv_copy(environ);
if (!m->environment)
r = manager_default_environment(m);
if (r < 0)
goto fail;
manager_strip_environment(m);
if (!(m->units = hashmap_new(string_hash_func, string_compare_func)))
goto fail;
@ -2651,7 +2664,7 @@ void manager_undo_generators(Manager *m) {
remove_generator_dir(m, &m->generator_unit_path_late);
}
int manager_set_default_environment(Manager *m, char **environment) {
int manager_environment_add(Manager *m, char **environment) {
char **e = NULL;
assert(m);

2
src/core/manager.h
View File

@ -281,7 +281,7 @@ unsigned manager_dispatch_load_queue(Manager *m);
unsigned manager_dispatch_run_queue(Manager *m);
unsigned manager_dispatch_dbus_queue(Manager *m);
int manager_set_default_environment(Manager *m, char **environment);
int manager_environment_add(Manager *m, char **environment);
int manager_set_default_rlimits(Manager *m, struct rlimit **default_rlimit);
int manager_loop(Manager *m);

15
src/shared/strv.c
View File

@ -387,6 +387,21 @@ fail:
return NULL;
}
char **strv_appendf(char **l, const char *format, ...) {
va_list ap;
_cleanup_free_ char *s = NULL;
int r;
va_start(ap, format);
r = vasprintf(&s, format, ap);
va_end(ap);
if (r < 0)
return NULL;
return strv_append(l, s);
}
int strv_push(char ***l, char *value) {
char **c;
unsigned n;

1
src/shared/strv.h
View File

@ -42,6 +42,7 @@ unsigned strv_length(char * const *l) _pure_;
char **strv_merge(char **a, char **b);
char **strv_merge_concat(char **a, char **b, const char *suffix);
char **strv_append(char **l, const char *s);
char **strv_appendf(char **l, const char *format, ...) _printf_attr_(2, 3);
int strv_extend(char ***l, const char *value);
int strv_push(char ***l, char *value);