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core/exec-invoke: use heap allocation to build environment variables

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We sometimes forget to increase the size N_ENV_VARS. Let's use heap
allocation.
This commit is contained in:
Yu Watanabe
2025-11-01 00:59:41 +09:00
parent 19bbcd35d7
commit bafbcd3b27
1 changed files with 82 additions and 107 deletions
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src/core/exec-invoke.c
+82 -107
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@@ -1999,9 +1999,8 @@ static int build_environment(
bool needs_sandboxing,
char ***ret) {
_cleanup_strv_free_ char **our_env = NULL;
size_t n_env = 0;
char *x;
_cleanup_strv_free_ char **e = NULL;
size_t n = 0;
int r;
assert(c);
@@ -2009,57 +2008,50 @@ static int build_environment(
assert(cgroup_context);
assert(ret);
#define N_ENV_VARS 20
our_env = new0(char*, N_ENV_VARS + _EXEC_DIRECTORY_TYPE_MAX + 1);
if (!our_env)
return -ENOMEM;
if (p->n_socket_fds + p->n_stashed_fds > 0) {
_cleanup_free_ char *joined = NULL;
if (asprintf(&x, "LISTEN_PID="PID_FMT, getpid_cached()) < 0)
return -ENOMEM;
our_env[n_env++] = x;
r = strv_extendf_with_size(&e, &n, "LISTEN_PID="PID_FMT, getpid_cached());
if (r < 0)
return r;
uint64_t pidfdid;
if (pidfd_get_inode_id_self_cached(&pidfdid) >= 0) {
if (asprintf(&x, "LISTEN_PIDFDID=%"PRIu64, pidfdid) < 0)
return -ENOMEM;
our_env[n_env++] = x;
r = strv_extendf_with_size(&e, &n, "LISTEN_PIDFDID=%"PRIu64, pidfdid);
if (r < 0)
return r;
}
if (asprintf(&x, "LISTEN_FDS=%zu", p->n_socket_fds + p->n_stashed_fds) < 0)
return -ENOMEM;
our_env[n_env++] = x;
r = strv_extendf_with_size(&e, &n, "LISTEN_FDS=%zu", p->n_socket_fds + p->n_stashed_fds);
if (r < 0)
return r;
joined = strv_join(p->fd_names, ":");
if (!joined)
return -ENOMEM;
x = strjoin("LISTEN_FDNAMES=", joined);
if (!x)
return -ENOMEM;
our_env[n_env++] = x;
r = strv_extend_joined_with_size(&e, &n, "LISTEN_FDNAMES=", joined);
if (r < 0)
return r;
}
if ((p->flags & EXEC_SET_WATCHDOG) && p->watchdog_usec > 0) {
if (asprintf(&x, "WATCHDOG_PID="PID_FMT, getpid_cached()) < 0)
return -ENOMEM;
our_env[n_env++] = x;
r = strv_extendf_with_size(&e, &n, "WATCHDOG_PID="PID_FMT, getpid_cached());
if (r < 0)
return r;
if (asprintf(&x, "WATCHDOG_USEC="USEC_FMT, p->watchdog_usec) < 0)
return -ENOMEM;
our_env[n_env++] = x;
r = strv_extendf_with_size(&e, &n, "WATCHDOG_USEC="USEC_FMT, p->watchdog_usec);
if (r < 0)
return r;
}
/* If this is D-Bus, tell the nss-systemd module, since it relies on being able to use blocking
* Varlink calls back to us for look up dynamic users in PID 1. Break the deadlock between D-Bus and
* PID 1 by disabling use of PID1' NSS interface for looking up dynamic users. */
if (p->flags & EXEC_NSS_DYNAMIC_BYPASS) {
x = strdup("SYSTEMD_NSS_DYNAMIC_BYPASS=1");
if (!x)
return -ENOMEM;
our_env[n_env++] = x;
r = strv_extend_with_size(&e, &n, "SYSTEMD_NSS_DYNAMIC_BYPASS=1");
if (r < 0)
return r;
}
/* We query "root" if this is a system unit and User= is not specified. $USER is always set. $HOME
@@ -2077,16 +2069,14 @@ static int build_environment(
bool set_user_login_env = exec_context_get_set_login_environment(c);
if (username) {
x = strjoin("USER=", username);
if (!x)
return -ENOMEM;
our_env[n_env++] = x;
r = strv_extend_joined_with_size(&e, &n, "USER=", username);
if (r < 0)
return r;
if (set_user_login_env) {
x = strjoin("LOGNAME=", username);
if (!x)
return -ENOMEM;
our_env[n_env++] = x;
r = strv_extend_joined_with_size(&e, &n, "LOGNAME=", username);
if (r < 0)
return r;
}
}
@@ -2094,51 +2084,51 @@ static int build_environment(
* (i.e. are "/" or "/bin/nologin"). */
if (home && set_user_login_env && !empty_or_root(home)) {
x = strjoin("HOME=", home);
if (!x)
return -ENOMEM;
_cleanup_free_ char *x = NULL;
path_simplify(x + 5);
our_env[n_env++] = x;
r = path_simplify_alloc(home, &x);
if (r < 0)
return r;
r = strv_extend_joined_with_size(&e, &n, "HOME=", x);
if (r < 0)
return r;
}
if (shell && set_user_login_env && !shell_is_placeholder(shell)) {
x = strjoin("SHELL=", shell);
if (!x)
return -ENOMEM;
_cleanup_free_ char *x = NULL;
path_simplify(x + 6);
our_env[n_env++] = x;
r = path_simplify_alloc(shell, &x);
if (r < 0)
return r;
r = strv_extend_joined_with_size(&e, &n, "SHELL=", x);
if (r < 0)
return r;
}
if (!sd_id128_is_null(p->invocation_id)) {
assert(p->invocation_id_string);
x = strjoin("INVOCATION_ID=", p->invocation_id_string);
if (!x)
return -ENOMEM;
our_env[n_env++] = x;
r = strv_extend_joined_with_size(&e, &n, "INVOCATION_ID=", p->invocation_id_string);
if (r < 0)
return r;
}
if (journal_stream_dev != 0 && journal_stream_ino != 0) {
if (asprintf(&x, "JOURNAL_STREAM=" DEV_FMT ":" INO_FMT, journal_stream_dev, journal_stream_ino) < 0)
return -ENOMEM;
our_env[n_env++] = x;
r = strv_extendf_with_size(&e, &n, "JOURNAL_STREAM=" DEV_FMT ":" INO_FMT, journal_stream_dev, journal_stream_ino);
if (r < 0)
return r;
}
if (c->log_namespace) {
x = strjoin("LOG_NAMESPACE=", c->log_namespace);
if (!x)
return -ENOMEM;
our_env[n_env++] = x;
r = strv_extend_joined_with_size(&e, &n, "LOG_NAMESPACE=", c->log_namespace);
if (r < 0)
return r;
}
for (ExecDirectoryType t = 0; t < _EXEC_DIRECTORY_TYPE_MAX; t++) {
_cleanup_free_ char *joined = NULL;
const char *n;
if (!p->prefix[t])
continue;
@@ -2146,8 +2136,8 @@ static int build_environment(
if (c->directories[t].n_items == 0)
continue;
n = exec_directory_env_name_to_string(t);
if (!n)
const char *name = exec_directory_env_name_to_string(t);
if (!name)
continue;
for (size_t i = 0; i < c->directories[t].n_items; i++) {
@@ -2161,11 +2151,9 @@ static int build_environment(
return -ENOMEM;
}
x = strjoin(n, "=", joined);
if (!x)
return -ENOMEM;
our_env[n_env++] = x;
r = strv_extend_joined_with_size(&e, &n, name, "=", joined);
if (r < 0)
return r;
}
_cleanup_free_ char *creds_dir = NULL;
@@ -2173,27 +2161,22 @@ static int build_environment(
if (r < 0)
return r;
if (r > 0) {
x = strjoin("CREDENTIALS_DIRECTORY=", creds_dir);
if (!x)
return -ENOMEM;
our_env[n_env++] = x;
r = strv_extend_joined_with_size(&e, &n, "CREDENTIALS_DIRECTORY=", creds_dir);
if (r < 0)
return r;
}
if (asprintf(&x, "SYSTEMD_EXEC_PID=" PID_FMT, getpid_cached()) < 0)
return -ENOMEM;
our_env[n_env++] = x;
r = strv_extendf_with_size(&e, &n, "SYSTEMD_EXEC_PID=" PID_FMT, getpid_cached());
if (r < 0)
return r;
if (memory_pressure_path) {
x = strjoin("MEMORY_PRESSURE_WATCH=", memory_pressure_path);
if (!x)
return -ENOMEM;
our_env[n_env++] = x;
r = strv_extend_joined_with_size(&e, &n, "MEMORY_PRESSURE_WATCH=", memory_pressure_path);
if (r < 0)
return r;
if (!path_equal(memory_pressure_path, "/dev/null")) {
_cleanup_free_ char *b = NULL, *e = NULL;
_cleanup_free_ char *b = NULL, *x = NULL;
if (asprintf(&b, "%s " USEC_FMT " " USEC_FMT,
MEMORY_PRESSURE_DEFAULT_TYPE,
@@ -2202,23 +2185,21 @@ static int build_environment(
MEMORY_PRESSURE_DEFAULT_WINDOW_USEC) < 0)
return -ENOMEM;
if (base64mem(b, strlen(b) + 1, &e) < 0)
if (base64mem(b, strlen(b) + 1, &x) < 0)
return -ENOMEM;
x = strjoin("MEMORY_PRESSURE_WRITE=", e);
if (!x)
return -ENOMEM;
our_env[n_env++] = x;
r = strv_extend_joined_with_size(&e, &n, "MEMORY_PRESSURE_WRITE=", x);
if (r < 0)
return r;
}
}
if (p->notify_socket) {
x = strjoin("NOTIFY_SOCKET=", exec_get_private_notify_socket_path(c, p, needs_sandboxing) ?: p->notify_socket);
if (!x)
return -ENOMEM;
our_env[n_env++] = x;
r = strv_extend_joined_with_size(
&e, &n, "NOTIFY_SOCKET=",
exec_get_private_notify_socket_path(c, p, needs_sandboxing) ?: p->notify_socket);
if (r < 0)
return r;
}
assert(c->private_var_tmp >= 0 && c->private_var_tmp < _PRIVATE_TMP_MAX);
@@ -2229,18 +2210,12 @@ static int build_environment(
/* When private tmpfs is enabled only on /tmp/, then explicitly set $TMPDIR to suggest the
* service to use /tmp/. */
x = strdup("TMPDIR=/tmp");
if (!x)
return -ENOMEM;
our_env[n_env++] = x;
r = strv_extend_with_size(&e, &n, "TMPDIR=/tmp");
if (r < 0)
return r;
}
assert(n_env <= N_ENV_VARS + _EXEC_DIRECTORY_TYPE_MAX);
#undef N_ENV_VARS
*ret = TAKE_PTR(our_env);
*ret = TAKE_PTR(e);
return 0;
}