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-rw-r--r--src/basic/process-util.c2060
1 files changed, 2060 insertions, 0 deletions
diff --git a/src/basic/process-util.c b/src/basic/process-util.c
new file mode 100644
index 0000000..4492e7d
--- /dev/null
+++ b/src/basic/process-util.c
@@ -0,0 +1,2060 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <ctype.h>
+#include <errno.h>
+#include <limits.h>
+#include <linux/oom.h>
+#include <pthread.h>
+#include <spawn.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/mount.h>
+#include <sys/personality.h>
+#include <sys/prctl.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <syslog.h>
+#include <unistd.h>
+#if HAVE_VALGRIND_VALGRIND_H
+#include <valgrind/valgrind.h>
+#endif
+
+#include "sd-messages.h"
+
+#include "alloc-util.h"
+#include "architecture.h"
+#include "argv-util.h"
+#include "dirent-util.h"
+#include "env-file.h"
+#include "env-util.h"
+#include "errno-util.h"
+#include "escape.h"
+#include "fd-util.h"
+#include "fileio.h"
+#include "fs-util.h"
+#include "hostname-util.h"
+#include "locale-util.h"
+#include "log.h"
+#include "macro.h"
+#include "memory-util.h"
+#include "missing_sched.h"
+#include "missing_syscall.h"
+#include "missing_threads.h"
+#include "mountpoint-util.h"
+#include "namespace-util.h"
+#include "nulstr-util.h"
+#include "parse-util.h"
+#include "path-util.h"
+#include "process-util.h"
+#include "raw-clone.h"
+#include "rlimit-util.h"
+#include "signal-util.h"
+#include "stat-util.h"
+#include "stdio-util.h"
+#include "string-table.h"
+#include "string-util.h"
+#include "terminal-util.h"
+#include "user-util.h"
+#include "utf8.h"
+
+/* The kernel limits userspace processes to TASK_COMM_LEN (16 bytes), but allows higher values for its own
+ * workers, e.g. "kworker/u9:3-kcryptd/253:0". Let's pick a fixed smallish limit that will work for the kernel.
+ */
+#define COMM_MAX_LEN 128
+
+static int get_process_state(pid_t pid) {
+ _cleanup_free_ char *line = NULL;
+ const char *p;
+ char state;
+ int r;
+
+ assert(pid >= 0);
+
+ /* Shortcut: if we are enquired about our own state, we are obviously running */
+ if (pid == 0 || pid == getpid_cached())
+ return (unsigned char) 'R';
+
+ p = procfs_file_alloca(pid, "stat");
+
+ r = read_one_line_file(p, &line);
+ if (r == -ENOENT)
+ return -ESRCH;
+ if (r < 0)
+ return r;
+
+ p = strrchr(line, ')');
+ if (!p)
+ return -EIO;
+
+ p++;
+
+ if (sscanf(p, " %c", &state) != 1)
+ return -EIO;
+
+ return (unsigned char) state;
+}
+
+int pid_get_comm(pid_t pid, char **ret) {
+ _cleanup_free_ char *escaped = NULL, *comm = NULL;
+ int r;
+
+ assert(ret);
+ assert(pid >= 0);
+
+ if (pid == 0 || pid == getpid_cached()) {
+ comm = new0(char, TASK_COMM_LEN + 1); /* Must fit in 16 byte according to prctl(2) */
+ if (!comm)
+ return -ENOMEM;
+
+ if (prctl(PR_GET_NAME, comm) < 0)
+ return -errno;
+ } else {
+ const char *p;
+
+ p = procfs_file_alloca(pid, "comm");
+
+ /* Note that process names of kernel threads can be much longer than TASK_COMM_LEN */
+ r = read_one_line_file(p, &comm);
+ if (r == -ENOENT)
+ return -ESRCH;
+ if (r < 0)
+ return r;
+ }
+
+ escaped = new(char, COMM_MAX_LEN);
+ if (!escaped)
+ return -ENOMEM;
+
+ /* Escape unprintable characters, just in case, but don't grow the string beyond the underlying size */
+ cellescape(escaped, COMM_MAX_LEN, comm);
+
+ *ret = TAKE_PTR(escaped);
+ return 0;
+}
+
+int pidref_get_comm(const PidRef *pid, char **ret) {
+ _cleanup_free_ char *comm = NULL;
+ int r;
+
+ if (!pidref_is_set(pid))
+ return -ESRCH;
+
+ r = pid_get_comm(pid->pid, &comm);
+ if (r < 0)
+ return r;
+
+ r = pidref_verify(pid);
+ if (r < 0)
+ return r;
+
+ if (ret)
+ *ret = TAKE_PTR(comm);
+ return 0;
+}
+
+static int pid_get_cmdline_nulstr(
+ pid_t pid,
+ size_t max_size,
+ ProcessCmdlineFlags flags,
+ char **ret,
+ size_t *ret_size) {
+
+ _cleanup_free_ char *t = NULL;
+ const char *p;
+ size_t k;
+ int r;
+
+ /* Retrieves a process' command line as a "sized nulstr", i.e. possibly without the last NUL, but
+ * with a specified size.
+ *
+ * If PROCESS_CMDLINE_COMM_FALLBACK is specified in flags and the process has no command line set
+ * (the case for kernel threads), or has a command line that resolves to the empty string, will
+ * return the "comm" name of the process instead. This will use at most _SC_ARG_MAX bytes of input
+ * data.
+ *
+ * Returns an error, 0 if output was read but is truncated, 1 otherwise.
+ */
+
+ p = procfs_file_alloca(pid, "cmdline");
+ r = read_virtual_file(p, max_size, &t, &k); /* Let's assume that each input byte results in >= 1
+ * columns of output. We ignore zero-width codepoints. */
+ if (r == -ENOENT)
+ return -ESRCH;
+ if (r < 0)
+ return r;
+
+ if (k == 0) {
+ if (!(flags & PROCESS_CMDLINE_COMM_FALLBACK))
+ return -ENOENT;
+
+ /* Kernel threads have no argv[] */
+ _cleanup_free_ char *comm = NULL;
+
+ r = pid_get_comm(pid, &comm);
+ if (r < 0)
+ return r;
+
+ free(t);
+ t = strjoin("[", comm, "]");
+ if (!t)
+ return -ENOMEM;
+
+ k = strlen(t);
+ r = k <= max_size;
+ if (r == 0) /* truncation */
+ t[max_size] = '\0';
+ }
+
+ if (ret)
+ *ret = TAKE_PTR(t);
+ if (ret_size)
+ *ret_size = k;
+
+ return r;
+}
+
+int pid_get_cmdline(pid_t pid, size_t max_columns, ProcessCmdlineFlags flags, char **ret) {
+ _cleanup_free_ char *t = NULL;
+ size_t k;
+ char *ans;
+
+ assert(pid >= 0);
+ assert(ret);
+
+ /* Retrieve and format a command line. See above for discussion of retrieval options.
+ *
+ * There are two main formatting modes:
+ *
+ * - when PROCESS_CMDLINE_QUOTE is specified, output is quoted in C/Python style. If no shell special
+ * characters are present, this output can be copy-pasted into the terminal to execute. UTF-8
+ * output is assumed.
+ *
+ * - otherwise, a compact non-roundtrippable form is returned. Non-UTF8 bytes are replaced by �. The
+ * returned string is of the specified console width at most, abbreviated with an ellipsis.
+ *
+ * Returns -ESRCH if the process doesn't exist, and -ENOENT if the process has no command line (and
+ * PROCESS_CMDLINE_COMM_FALLBACK is not specified). Returns 0 and sets *line otherwise. */
+
+ int full = pid_get_cmdline_nulstr(pid, max_columns, flags, &t, &k);
+ if (full < 0)
+ return full;
+
+ if (flags & (PROCESS_CMDLINE_QUOTE | PROCESS_CMDLINE_QUOTE_POSIX)) {
+ ShellEscapeFlags shflags = SHELL_ESCAPE_EMPTY |
+ FLAGS_SET(flags, PROCESS_CMDLINE_QUOTE_POSIX) * SHELL_ESCAPE_POSIX;
+
+ assert(!(flags & PROCESS_CMDLINE_USE_LOCALE));
+
+ _cleanup_strv_free_ char **args = NULL;
+
+ /* Drop trailing NULs, otherwise strv_parse_nulstr() adds additional empty strings at the end.
+ * See also issue #21186. */
+ args = strv_parse_nulstr_full(t, k, /* drop_trailing_nuls = */ true);
+ if (!args)
+ return -ENOMEM;
+
+ ans = quote_command_line(args, shflags);
+ if (!ans)
+ return -ENOMEM;
+ } else {
+ /* Arguments are separated by NULs. Let's replace those with spaces. */
+ for (size_t i = 0; i < k - 1; i++)
+ if (t[i] == '\0')
+ t[i] = ' ';
+
+ delete_trailing_chars(t, WHITESPACE);
+
+ bool eight_bit = (flags & PROCESS_CMDLINE_USE_LOCALE) && !is_locale_utf8();
+
+ ans = escape_non_printable_full(t, max_columns,
+ eight_bit * XESCAPE_8_BIT | !full * XESCAPE_FORCE_ELLIPSIS);
+ if (!ans)
+ return -ENOMEM;
+
+ ans = str_realloc(ans);
+ }
+
+ *ret = ans;
+ return 0;
+}
+
+int pidref_get_cmdline(const PidRef *pid, size_t max_columns, ProcessCmdlineFlags flags, char **ret) {
+ _cleanup_free_ char *s = NULL;
+ int r;
+
+ if (!pidref_is_set(pid))
+ return -ESRCH;
+
+ r = pid_get_cmdline(pid->pid, max_columns, flags, &s);
+ if (r < 0)
+ return r;
+
+ r = pidref_verify(pid);
+ if (r < 0)
+ return r;
+
+ if (ret)
+ *ret = TAKE_PTR(s);
+ return 0;
+}
+
+int pid_get_cmdline_strv(pid_t pid, ProcessCmdlineFlags flags, char ***ret) {
+ _cleanup_free_ char *t = NULL;
+ char **args;
+ size_t k;
+ int r;
+
+ assert(pid >= 0);
+ assert((flags & ~PROCESS_CMDLINE_COMM_FALLBACK) == 0);
+ assert(ret);
+
+ r = pid_get_cmdline_nulstr(pid, SIZE_MAX, flags, &t, &k);
+ if (r < 0)
+ return r;
+
+ args = strv_parse_nulstr_full(t, k, /* drop_trailing_nuls = */ true);
+ if (!args)
+ return -ENOMEM;
+
+ *ret = args;
+ return 0;
+}
+
+int pidref_get_cmdline_strv(const PidRef *pid, ProcessCmdlineFlags flags, char ***ret) {
+ _cleanup_strv_free_ char **args = NULL;
+ int r;
+
+ if (!pidref_is_set(pid))
+ return -ESRCH;
+
+ r = pid_get_cmdline_strv(pid->pid, flags, &args);
+ if (r < 0)
+ return r;
+
+ r = pidref_verify(pid);
+ if (r < 0)
+ return r;
+
+ if (ret)
+ *ret = TAKE_PTR(args);
+
+ return 0;
+}
+
+int container_get_leader(const char *machine, pid_t *pid) {
+ _cleanup_free_ char *s = NULL, *class = NULL;
+ const char *p;
+ pid_t leader;
+ int r;
+
+ assert(machine);
+ assert(pid);
+
+ if (streq(machine, ".host")) {
+ *pid = 1;
+ return 0;
+ }
+
+ if (!hostname_is_valid(machine, 0))
+ return -EINVAL;
+
+ p = strjoina("/run/systemd/machines/", machine);
+ r = parse_env_file(NULL, p,
+ "LEADER", &s,
+ "CLASS", &class);
+ if (r == -ENOENT)
+ return -EHOSTDOWN;
+ if (r < 0)
+ return r;
+ if (!s)
+ return -EIO;
+
+ if (!streq_ptr(class, "container"))
+ return -EIO;
+
+ r = parse_pid(s, &leader);
+ if (r < 0)
+ return r;
+ if (leader <= 1)
+ return -EIO;
+
+ *pid = leader;
+ return 0;
+}
+
+int namespace_get_leader(pid_t pid, NamespaceType type, pid_t *ret) {
+ int r;
+
+ assert(ret);
+
+ for (;;) {
+ pid_t ppid;
+
+ r = get_process_ppid(pid, &ppid);
+ if (r < 0)
+ return r;
+
+ r = in_same_namespace(pid, ppid, type);
+ if (r < 0)
+ return r;
+ if (r == 0) {
+ /* If the parent and the child are not in the same
+ * namespace, then the child is the leader we are
+ * looking for. */
+ *ret = pid;
+ return 0;
+ }
+
+ pid = ppid;
+ }
+}
+
+int pid_is_kernel_thread(pid_t pid) {
+ _cleanup_free_ char *line = NULL;
+ unsigned long long flags;
+ size_t l, i;
+ const char *p;
+ char *q;
+ int r;
+
+ if (IN_SET(pid, 0, 1) || pid == getpid_cached()) /* pid 1, and we ourselves certainly aren't a kernel thread */
+ return 0;
+ if (!pid_is_valid(pid))
+ return -EINVAL;
+
+ p = procfs_file_alloca(pid, "stat");
+ r = read_one_line_file(p, &line);
+ if (r == -ENOENT)
+ return -ESRCH;
+ if (r < 0)
+ return r;
+
+ /* Skip past the comm field */
+ q = strrchr(line, ')');
+ if (!q)
+ return -EINVAL;
+ q++;
+
+ /* Skip 6 fields to reach the flags field */
+ for (i = 0; i < 6; i++) {
+ l = strspn(q, WHITESPACE);
+ if (l < 1)
+ return -EINVAL;
+ q += l;
+
+ l = strcspn(q, WHITESPACE);
+ if (l < 1)
+ return -EINVAL;
+ q += l;
+ }
+
+ /* Skip preceding whitespace */
+ l = strspn(q, WHITESPACE);
+ if (l < 1)
+ return -EINVAL;
+ q += l;
+
+ /* Truncate the rest */
+ l = strcspn(q, WHITESPACE);
+ if (l < 1)
+ return -EINVAL;
+ q[l] = 0;
+
+ r = safe_atollu(q, &flags);
+ if (r < 0)
+ return r;
+
+ return !!(flags & PF_KTHREAD);
+}
+
+int pidref_is_kernel_thread(const PidRef *pid) {
+ int result, r;
+
+ if (!pidref_is_set(pid))
+ return -ESRCH;
+
+ result = pid_is_kernel_thread(pid->pid);
+ if (result < 0)
+ return result;
+
+ r = pidref_verify(pid); /* Verify that the PID wasn't reused since */
+ if (r < 0)
+ return r;
+
+ return result;
+}
+
+int get_process_capeff(pid_t pid, char **ret) {
+ const char *p;
+ int r;
+
+ assert(pid >= 0);
+ assert(ret);
+
+ p = procfs_file_alloca(pid, "status");
+
+ r = get_proc_field(p, "CapEff", WHITESPACE, ret);
+ if (r == -ENOENT)
+ return -ESRCH;
+
+ return r;
+}
+
+static int get_process_link_contents(pid_t pid, const char *proc_file, char **ret) {
+ const char *p;
+ int r;
+
+ assert(proc_file);
+
+ p = procfs_file_alloca(pid, proc_file);
+
+ r = readlink_malloc(p, ret);
+ return r == -ENOENT ? -ESRCH : r;
+}
+
+int get_process_exe(pid_t pid, char **ret) {
+ char *d;
+ int r;
+
+ assert(pid >= 0);
+
+ r = get_process_link_contents(pid, "exe", ret);
+ if (r < 0)
+ return r;
+
+ if (ret) {
+ d = endswith(*ret, " (deleted)");
+ if (d)
+ *d = '\0';
+ }
+
+ return 0;
+}
+
+static int get_process_id(pid_t pid, const char *field, uid_t *ret) {
+ _cleanup_fclose_ FILE *f = NULL;
+ const char *p;
+ int r;
+
+ assert(field);
+ assert(ret);
+
+ if (pid < 0)
+ return -EINVAL;
+
+ p = procfs_file_alloca(pid, "status");
+ r = fopen_unlocked(p, "re", &f);
+ if (r == -ENOENT)
+ return -ESRCH;
+ if (r < 0)
+ return r;
+
+ for (;;) {
+ _cleanup_free_ char *line = NULL;
+ char *l;
+
+ r = read_stripped_line(f, LONG_LINE_MAX, &line);
+ if (r < 0)
+ return r;
+ if (r == 0)
+ break;
+
+ l = startswith(line, field);
+ if (l) {
+ l += strspn(l, WHITESPACE);
+
+ l[strcspn(l, WHITESPACE)] = 0;
+
+ return parse_uid(l, ret);
+ }
+ }
+
+ return -EIO;
+}
+
+int pid_get_uid(pid_t pid, uid_t *ret) {
+ assert(ret);
+
+ if (pid == 0 || pid == getpid_cached()) {
+ *ret = getuid();
+ return 0;
+ }
+
+ return get_process_id(pid, "Uid:", ret);
+}
+
+int pidref_get_uid(const PidRef *pid, uid_t *ret) {
+ uid_t uid;
+ int r;
+
+ if (!pidref_is_set(pid))
+ return -ESRCH;
+
+ r = pid_get_uid(pid->pid, &uid);
+ if (r < 0)
+ return r;
+
+ r = pidref_verify(pid);
+ if (r < 0)
+ return r;
+
+ if (ret)
+ *ret = uid;
+ return 0;
+}
+
+int get_process_gid(pid_t pid, gid_t *ret) {
+
+ if (pid == 0 || pid == getpid_cached()) {
+ *ret = getgid();
+ return 0;
+ }
+
+ assert_cc(sizeof(uid_t) == sizeof(gid_t));
+ return get_process_id(pid, "Gid:", ret);
+}
+
+int get_process_cwd(pid_t pid, char **ret) {
+ assert(pid >= 0);
+
+ if (pid == 0 || pid == getpid_cached())
+ return safe_getcwd(ret);
+
+ return get_process_link_contents(pid, "cwd", ret);
+}
+
+int get_process_root(pid_t pid, char **ret) {
+ assert(pid >= 0);
+ return get_process_link_contents(pid, "root", ret);
+}
+
+#define ENVIRONMENT_BLOCK_MAX (5U*1024U*1024U)
+
+int get_process_environ(pid_t pid, char **ret) {
+ _cleanup_fclose_ FILE *f = NULL;
+ _cleanup_free_ char *outcome = NULL;
+ size_t sz = 0;
+ const char *p;
+ int r;
+
+ assert(pid >= 0);
+ assert(ret);
+
+ p = procfs_file_alloca(pid, "environ");
+
+ r = fopen_unlocked(p, "re", &f);
+ if (r == -ENOENT)
+ return -ESRCH;
+ if (r < 0)
+ return r;
+
+ for (;;) {
+ char c;
+
+ if (sz >= ENVIRONMENT_BLOCK_MAX)
+ return -ENOBUFS;
+
+ if (!GREEDY_REALLOC(outcome, sz + 5))
+ return -ENOMEM;
+
+ r = safe_fgetc(f, &c);
+ if (r < 0)
+ return r;
+ if (r == 0)
+ break;
+
+ if (c == '\0')
+ outcome[sz++] = '\n';
+ else
+ sz += cescape_char(c, outcome + sz);
+ }
+
+ outcome[sz] = '\0';
+ *ret = TAKE_PTR(outcome);
+
+ return 0;
+}
+
+int get_process_ppid(pid_t pid, pid_t *ret) {
+ _cleanup_free_ char *line = NULL;
+ unsigned long ppid;
+ const char *p;
+ int r;
+
+ assert(pid >= 0);
+
+ if (pid == 0 || pid == getpid_cached()) {
+ if (ret)
+ *ret = getppid();
+ return 0;
+ }
+
+ if (pid == 1) /* PID 1 has no parent, shortcut this case */
+ return -EADDRNOTAVAIL;
+
+ p = procfs_file_alloca(pid, "stat");
+ r = read_one_line_file(p, &line);
+ if (r == -ENOENT)
+ return -ESRCH;
+ if (r < 0)
+ return r;
+
+ /* Let's skip the pid and comm fields. The latter is enclosed in () but does not escape any () in its
+ * value, so let's skip over it manually */
+
+ p = strrchr(line, ')');
+ if (!p)
+ return -EIO;
+
+ p++;
+
+ if (sscanf(p, " "
+ "%*c " /* state */
+ "%lu ", /* ppid */
+ &ppid) != 1)
+ return -EIO;
+
+ /* If ppid is zero the process has no parent. Which might be the case for PID 1 but also for
+ * processes originating in other namespaces that are inserted into a pidns. Return a recognizable
+ * error in this case. */
+ if (ppid == 0)
+ return -EADDRNOTAVAIL;
+
+ if ((pid_t) ppid < 0 || (unsigned long) (pid_t) ppid != ppid)
+ return -ERANGE;
+
+ if (ret)
+ *ret = (pid_t) ppid;
+
+ return 0;
+}
+
+int get_process_umask(pid_t pid, mode_t *ret) {
+ _cleanup_free_ char *m = NULL;
+ const char *p;
+ int r;
+
+ assert(pid >= 0);
+ assert(ret);
+
+ p = procfs_file_alloca(pid, "status");
+
+ r = get_proc_field(p, "Umask", WHITESPACE, &m);
+ if (r == -ENOENT)
+ return -ESRCH;
+ if (r < 0)
+ return r;
+
+ return parse_mode(m, ret);
+}
+
+int wait_for_terminate(pid_t pid, siginfo_t *status) {
+ siginfo_t dummy;
+
+ assert(pid >= 1);
+
+ if (!status)
+ status = &dummy;
+
+ for (;;) {
+ zero(*status);
+
+ if (waitid(P_PID, pid, status, WEXITED) < 0) {
+
+ if (errno == EINTR)
+ continue;
+
+ return negative_errno();
+ }
+
+ return 0;
+ }
+}
+
+/*
+ * Return values:
+ * < 0 : wait_for_terminate() failed to get the state of the
+ * process, the process was terminated by a signal, or
+ * failed for an unknown reason.
+ * >=0 : The process terminated normally, and its exit code is
+ * returned.
+ *
+ * That is, success is indicated by a return value of zero, and an
+ * error is indicated by a non-zero value.
+ *
+ * A warning is emitted if the process terminates abnormally,
+ * and also if it returns non-zero unless check_exit_code is true.
+ */
+int wait_for_terminate_and_check(const char *name, pid_t pid, WaitFlags flags) {
+ _cleanup_free_ char *buffer = NULL;
+ siginfo_t status;
+ int r, prio;
+
+ assert(pid > 1);
+
+ if (!name) {
+ r = pid_get_comm(pid, &buffer);
+ if (r < 0)
+ log_debug_errno(r, "Failed to acquire process name of " PID_FMT ", ignoring: %m", pid);
+ else
+ name = buffer;
+ }
+
+ prio = flags & WAIT_LOG_ABNORMAL ? LOG_ERR : LOG_DEBUG;
+
+ r = wait_for_terminate(pid, &status);
+ if (r < 0)
+ return log_full_errno(prio, r, "Failed to wait for %s: %m", strna(name));
+
+ if (status.si_code == CLD_EXITED) {
+ if (status.si_status != EXIT_SUCCESS)
+ log_full(flags & WAIT_LOG_NON_ZERO_EXIT_STATUS ? LOG_ERR : LOG_DEBUG,
+ "%s failed with exit status %i.", strna(name), status.si_status);
+ else
+ log_debug("%s succeeded.", name);
+
+ return status.si_status;
+
+ } else if (IN_SET(status.si_code, CLD_KILLED, CLD_DUMPED)) {
+
+ log_full(prio, "%s terminated by signal %s.", strna(name), signal_to_string(status.si_status));
+ return -EPROTO;
+ }
+
+ log_full(prio, "%s failed due to unknown reason.", strna(name));
+ return -EPROTO;
+}
+
+/*
+ * Return values:
+ *
+ * < 0 : wait_for_terminate_with_timeout() failed to get the state of the process, the process timed out, the process
+ * was terminated by a signal, or failed for an unknown reason.
+ *
+ * >=0 : The process terminated normally with no failures.
+ *
+ * Success is indicated by a return value of zero, a timeout is indicated by ETIMEDOUT, and all other child failure
+ * states are indicated by error is indicated by a non-zero value.
+ *
+ * This call assumes SIGCHLD has been blocked already, in particular before the child to wait for has been forked off
+ * to remain entirely race-free.
+ */
+int wait_for_terminate_with_timeout(pid_t pid, usec_t timeout) {
+ sigset_t mask;
+ int r;
+ usec_t until;
+
+ assert_se(sigemptyset(&mask) == 0);
+ assert_se(sigaddset(&mask, SIGCHLD) == 0);
+
+ /* Drop into a sigtimewait-based timeout. Waiting for the
+ * pid to exit. */
+ until = usec_add(now(CLOCK_MONOTONIC), timeout);
+ for (;;) {
+ usec_t n;
+ siginfo_t status = {};
+
+ n = now(CLOCK_MONOTONIC);
+ if (n >= until)
+ break;
+
+ r = RET_NERRNO(sigtimedwait(&mask, NULL, TIMESPEC_STORE(until - n)));
+ /* Assuming we woke due to the child exiting. */
+ if (waitid(P_PID, pid, &status, WEXITED|WNOHANG) == 0) {
+ if (status.si_pid == pid) {
+ /* This is the correct child. */
+ if (status.si_code == CLD_EXITED)
+ return status.si_status == 0 ? 0 : -EPROTO;
+ else
+ return -EPROTO;
+ }
+ }
+ /* Not the child, check for errors and proceed appropriately */
+ if (r < 0) {
+ switch (r) {
+ case -EAGAIN:
+ /* Timed out, child is likely hung. */
+ return -ETIMEDOUT;
+ case -EINTR:
+ /* Received a different signal and should retry */
+ continue;
+ default:
+ /* Return any unexpected errors */
+ return r;
+ }
+ }
+ }
+
+ return -EPROTO;
+}
+
+void sigkill_wait(pid_t pid) {
+ assert(pid > 1);
+
+ (void) kill(pid, SIGKILL);
+ (void) wait_for_terminate(pid, NULL);
+}
+
+void sigkill_waitp(pid_t *pid) {
+ PROTECT_ERRNO;
+
+ if (!pid)
+ return;
+ if (*pid <= 1)
+ return;
+
+ sigkill_wait(*pid);
+}
+
+void sigterm_wait(pid_t pid) {
+ assert(pid > 1);
+
+ (void) kill_and_sigcont(pid, SIGTERM);
+ (void) wait_for_terminate(pid, NULL);
+}
+
+void sigkill_nowait(pid_t pid) {
+ assert(pid > 1);
+
+ (void) kill(pid, SIGKILL);
+}
+
+void sigkill_nowaitp(pid_t *pid) {
+ PROTECT_ERRNO;
+
+ if (!pid)
+ return;
+ if (*pid <= 1)
+ return;
+
+ sigkill_nowait(*pid);
+}
+
+int kill_and_sigcont(pid_t pid, int sig) {
+ int r;
+
+ r = RET_NERRNO(kill(pid, sig));
+
+ /* If this worked, also send SIGCONT, unless we already just sent a SIGCONT, or SIGKILL was sent which isn't
+ * affected by a process being suspended anyway. */
+ if (r >= 0 && !IN_SET(sig, SIGCONT, SIGKILL))
+ (void) kill(pid, SIGCONT);
+
+ return r;
+}
+
+int getenv_for_pid(pid_t pid, const char *field, char **ret) {
+ _cleanup_fclose_ FILE *f = NULL;
+ char *value = NULL;
+ const char *path;
+ size_t l, sum = 0;
+ int r;
+
+ assert(pid >= 0);
+ assert(field);
+ assert(ret);
+
+ if (pid == 0 || pid == getpid_cached()) {
+ const char *e;
+
+ e = getenv(field);
+ if (!e) {
+ *ret = NULL;
+ return 0;
+ }
+
+ value = strdup(e);
+ if (!value)
+ return -ENOMEM;
+
+ *ret = value;
+ return 1;
+ }
+
+ if (!pid_is_valid(pid))
+ return -EINVAL;
+
+ path = procfs_file_alloca(pid, "environ");
+
+ r = fopen_unlocked(path, "re", &f);
+ if (r == -ENOENT)
+ return -ESRCH;
+ if (r < 0)
+ return r;
+
+ l = strlen(field);
+ for (;;) {
+ _cleanup_free_ char *line = NULL;
+
+ if (sum > ENVIRONMENT_BLOCK_MAX) /* Give up searching eventually */
+ return -ENOBUFS;
+
+ r = read_nul_string(f, LONG_LINE_MAX, &line);
+ if (r < 0)
+ return r;
+ if (r == 0) /* EOF */
+ break;
+
+ sum += r;
+
+ if (strneq(line, field, l) && line[l] == '=') {
+ value = strdup(line + l + 1);
+ if (!value)
+ return -ENOMEM;
+
+ *ret = value;
+ return 1;
+ }
+ }
+
+ *ret = NULL;
+ return 0;
+}
+
+int pid_is_my_child(pid_t pid) {
+ pid_t ppid;
+ int r;
+
+ if (pid < 0)
+ return -ESRCH;
+
+ if (pid <= 1)
+ return false;
+
+ r = get_process_ppid(pid, &ppid);
+ if (r < 0)
+ return r;
+
+ return ppid == getpid_cached();
+}
+
+int pidref_is_my_child(const PidRef *pid) {
+ int r, result;
+
+ if (!pidref_is_set(pid))
+ return -ESRCH;
+
+ result = pid_is_my_child(pid->pid);
+ if (result < 0)
+ return result;
+
+ r = pidref_verify(pid);
+ if (r < 0)
+ return r;
+
+ return result;
+}
+
+int pid_is_unwaited(pid_t pid) {
+ /* Checks whether a PID is still valid at all, including a zombie */
+
+ if (pid < 0)
+ return -ESRCH;
+
+ if (pid <= 1) /* If we or PID 1 would be dead and have been waited for, this code would not be running */
+ return true;
+
+ if (pid == getpid_cached())
+ return true;
+
+ if (kill(pid, 0) >= 0)
+ return true;
+
+ return errno != ESRCH;
+}
+
+int pidref_is_unwaited(const PidRef *pid) {
+ int r;
+
+ if (!pidref_is_set(pid))
+ return -ESRCH;
+
+ if (pid->pid == 1 || pidref_is_self(pid))
+ return true;
+
+ r = pidref_kill(pid, 0);
+ if (r == -ESRCH)
+ return false;
+ if (r < 0)
+ return r;
+
+ return true;
+}
+
+int pid_is_alive(pid_t pid) {
+ int r;
+
+ /* Checks whether a PID is still valid and not a zombie */
+
+ if (pid < 0)
+ return -ESRCH;
+
+ if (pid <= 1) /* If we or PID 1 would be a zombie, this code would not be running */
+ return true;
+
+ if (pid == getpid_cached())
+ return true;
+
+ r = get_process_state(pid);
+ if (r == -ESRCH)
+ return false;
+ if (r < 0)
+ return r;
+
+ return r != 'Z';
+}
+
+int pidref_is_alive(const PidRef *pidref) {
+ int r, result;
+
+ if (!pidref_is_set(pidref))
+ return -ESRCH;
+
+ result = pid_is_alive(pidref->pid);
+ if (result < 0)
+ return result;
+
+ r = pidref_verify(pidref);
+ if (r == -ESRCH)
+ return false;
+ if (r < 0)
+ return r;
+
+ return result;
+}
+
+int pid_from_same_root_fs(pid_t pid) {
+ const char *root;
+
+ if (pid < 0)
+ return false;
+
+ if (pid == 0 || pid == getpid_cached())
+ return true;
+
+ root = procfs_file_alloca(pid, "root");
+
+ return inode_same(root, "/proc/1/root", 0);
+}
+
+bool is_main_thread(void) {
+ static thread_local int cached = 0;
+
+ if (_unlikely_(cached == 0))
+ cached = getpid_cached() == gettid() ? 1 : -1;
+
+ return cached > 0;
+}
+
+bool oom_score_adjust_is_valid(int oa) {
+ return oa >= OOM_SCORE_ADJ_MIN && oa <= OOM_SCORE_ADJ_MAX;
+}
+
+unsigned long personality_from_string(const char *p) {
+ Architecture architecture;
+
+ if (!p)
+ return PERSONALITY_INVALID;
+
+ /* Parse a personality specifier. We use our own identifiers that indicate specific ABIs, rather than just
+ * hints regarding the register size, since we want to keep things open for multiple locally supported ABIs for
+ * the same register size. */
+
+ architecture = architecture_from_string(p);
+ if (architecture < 0)
+ return PERSONALITY_INVALID;
+
+ if (architecture == native_architecture())
+ return PER_LINUX;
+#ifdef ARCHITECTURE_SECONDARY
+ if (architecture == ARCHITECTURE_SECONDARY)
+ return PER_LINUX32;
+#endif
+
+ return PERSONALITY_INVALID;
+}
+
+const char* personality_to_string(unsigned long p) {
+ Architecture architecture = _ARCHITECTURE_INVALID;
+
+ if (p == PER_LINUX)
+ architecture = native_architecture();
+#ifdef ARCHITECTURE_SECONDARY
+ else if (p == PER_LINUX32)
+ architecture = ARCHITECTURE_SECONDARY;
+#endif
+
+ if (architecture < 0)
+ return NULL;
+
+ return architecture_to_string(architecture);
+}
+
+int safe_personality(unsigned long p) {
+ int ret;
+
+ /* So here's the deal, personality() is weirdly defined by glibc. In some cases it returns a failure via errno,
+ * and in others as negative return value containing an errno-like value. Let's work around this: this is a
+ * wrapper that uses errno if it is set, and uses the return value otherwise. And then it sets both errno and
+ * the return value indicating the same issue, so that we are definitely on the safe side.
+ *
+ * See https://github.com/systemd/systemd/issues/6737 */
+
+ errno = 0;
+ ret = personality(p);
+ if (ret < 0) {
+ if (errno != 0)
+ return -errno;
+
+ errno = -ret;
+ }
+
+ return ret;
+}
+
+int opinionated_personality(unsigned long *ret) {
+ int current;
+
+ /* Returns the current personality, or PERSONALITY_INVALID if we can't determine it. This function is a bit
+ * opinionated though, and ignores all the finer-grained bits and exotic personalities, only distinguishing the
+ * two most relevant personalities: PER_LINUX and PER_LINUX32. */
+
+ current = safe_personality(PERSONALITY_INVALID);
+ if (current < 0)
+ return current;
+
+ if (((unsigned long) current & 0xffff) == PER_LINUX32)
+ *ret = PER_LINUX32;
+ else
+ *ret = PER_LINUX;
+
+ return 0;
+}
+
+void valgrind_summary_hack(void) {
+#if HAVE_VALGRIND_VALGRIND_H
+ if (getpid_cached() == 1 && RUNNING_ON_VALGRIND) {
+ pid_t pid;
+ pid = raw_clone(SIGCHLD);
+ if (pid < 0)
+ log_struct_errno(
+ LOG_EMERG, errno,
+ "MESSAGE_ID=" SD_MESSAGE_VALGRIND_HELPER_FORK_STR,
+ LOG_MESSAGE( "Failed to fork off valgrind helper: %m"));
+ else if (pid == 0)
+ exit(EXIT_SUCCESS);
+ else {
+ log_info("Spawned valgrind helper as PID "PID_FMT".", pid);
+ (void) wait_for_terminate(pid, NULL);
+ }
+ }
+#endif
+}
+
+int pid_compare_func(const pid_t *a, const pid_t *b) {
+ /* Suitable for usage in qsort() */
+ return CMP(*a, *b);
+}
+
+/* The cached PID, possible values:
+ *
+ * == UNSET [0] → cache not initialized yet
+ * == BUSY [-1] → some thread is initializing it at the moment
+ * any other → the cached PID
+ */
+
+#define CACHED_PID_UNSET ((pid_t) 0)
+#define CACHED_PID_BUSY ((pid_t) -1)
+
+static pid_t cached_pid = CACHED_PID_UNSET;
+
+void reset_cached_pid(void) {
+ /* Invoked in the child after a fork(), i.e. at the first moment the PID changed */
+ cached_pid = CACHED_PID_UNSET;
+}
+
+pid_t getpid_cached(void) {
+ static bool installed = false;
+ pid_t current_value = CACHED_PID_UNSET;
+
+ /* getpid_cached() is much like getpid(), but caches the value in local memory, to avoid having to invoke a
+ * system call each time. This restores glibc behaviour from before 2.24, when getpid() was unconditionally
+ * cached. Starting with 2.24 getpid() started to become prohibitively expensive when used for detecting when
+ * objects were used across fork()s. With this caching the old behaviour is somewhat restored.
+ *
+ * https://bugzilla.redhat.com/show_bug.cgi?id=1443976
+ * https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=c579f48edba88380635ab98cb612030e3ed8691e
+ */
+
+ (void) __atomic_compare_exchange_n(
+ &cached_pid,
+ &current_value,
+ CACHED_PID_BUSY,
+ false,
+ __ATOMIC_SEQ_CST,
+ __ATOMIC_SEQ_CST);
+
+ switch (current_value) {
+
+ case CACHED_PID_UNSET: { /* Not initialized yet, then do so now */
+ pid_t new_pid;
+
+ new_pid = raw_getpid();
+
+ if (!installed) {
+ /* __register_atfork() either returns 0 or -ENOMEM, in its glibc implementation. Since it's
+ * only half-documented (glibc doesn't document it but LSB does — though only superficially)
+ * we'll check for errors only in the most generic fashion possible. */
+
+ if (pthread_atfork(NULL, NULL, reset_cached_pid) != 0) {
+ /* OOM? Let's try again later */
+ cached_pid = CACHED_PID_UNSET;
+ return new_pid;
+ }
+
+ installed = true;
+ }
+
+ cached_pid = new_pid;
+ return new_pid;
+ }
+
+ case CACHED_PID_BUSY: /* Somebody else is currently initializing */
+ return raw_getpid();
+
+ default: /* Properly initialized */
+ return current_value;
+ }
+}
+
+int must_be_root(void) {
+
+ if (geteuid() == 0)
+ return 0;
+
+ return log_error_errno(SYNTHETIC_ERRNO(EPERM), "Need to be root.");
+}
+
+static void restore_sigsetp(sigset_t **ssp) {
+ if (*ssp)
+ (void) sigprocmask(SIG_SETMASK, *ssp, NULL);
+}
+
+pid_t clone_with_nested_stack(int (*fn)(void *), int flags, void *userdata) {
+ size_t ps;
+ pid_t pid;
+ void *mystack;
+
+ /* A wrapper around glibc's clone() call that automatically sets up a "nested" stack. Only supports
+ * invocations without CLONE_VM, so that we can continue to use the parent's stack mapping.
+ *
+ * Note: glibc's clone() wrapper does not synchronize malloc() locks. This means that if the parent
+ * is threaded these locks will be in an undefined state in the child, and hence memory allocations
+ * are likely going to run into deadlocks. Hence: if you use this function make sure your parent is
+ * strictly single-threaded or your child never calls malloc(). */
+
+ assert((flags & (CLONE_VM|CLONE_PARENT_SETTID|CLONE_CHILD_SETTID|
+ CLONE_CHILD_CLEARTID|CLONE_SETTLS)) == 0);
+
+ /* We allocate some space on the stack to use as the stack for the child (hence "nested"). Note that
+ * the net effect is that the child will have the start of its stack inside the stack of the parent,
+ * but since they are a CoW copy of each other that's fine. We allocate one page-aligned page. But
+ * since we don't want to deal with differences between systems where the stack grows backwards or
+ * forwards we'll allocate one more and place the stack address in the middle. Except that we also
+ * want it page aligned, hence we'll allocate one page more. Makes 3. */
+
+ ps = page_size();
+ mystack = alloca(ps*3);
+ mystack = (uint8_t*) mystack + ps; /* move pointer one page ahead since stacks usually grow backwards */
+ mystack = (void*) ALIGN_TO((uintptr_t) mystack, ps); /* align to page size (moving things further ahead) */
+
+#if HAVE_CLONE
+ pid = clone(fn, mystack, flags, userdata);
+#else
+ pid = __clone2(fn, mystack, ps, flags, userdata);
+#endif
+ if (pid < 0)
+ return -errno;
+
+ return pid;
+}
+
+static int fork_flags_to_signal(ForkFlags flags) {
+ return (flags & FORK_DEATHSIG_SIGTERM) ? SIGTERM :
+ (flags & FORK_DEATHSIG_SIGINT) ? SIGINT :
+ SIGKILL;
+}
+
+int safe_fork_full(
+ const char *name,
+ const int stdio_fds[3],
+ const int except_fds[],
+ size_t n_except_fds,
+ ForkFlags flags,
+ pid_t *ret_pid) {
+
+ pid_t original_pid, pid;
+ sigset_t saved_ss, ss;
+ _unused_ _cleanup_(restore_sigsetp) sigset_t *saved_ssp = NULL;
+ bool block_signals = false, block_all = false, intermediary = false;
+ int prio, r;
+
+ assert(!FLAGS_SET(flags, FORK_DETACH) || !ret_pid);
+ assert(!FLAGS_SET(flags, FORK_DETACH|FORK_WAIT));
+
+ /* A wrapper around fork(), that does a couple of important initializations in addition to mere forking. Always
+ * returns the child's PID in *ret_pid. Returns == 0 in the child, and > 0 in the parent. */
+
+ prio = flags & FORK_LOG ? LOG_ERR : LOG_DEBUG;
+
+ original_pid = getpid_cached();
+
+ if (flags & FORK_FLUSH_STDIO) {
+ fflush(stdout);
+ fflush(stderr); /* This one shouldn't be necessary, stderr should be unbuffered anyway, but let's better be safe than sorry */
+ }
+
+ if (flags & (FORK_RESET_SIGNALS|FORK_DEATHSIG_SIGTERM|FORK_DEATHSIG_SIGINT)) {
+ /* We temporarily block all signals, so that the new child has them blocked initially. This
+ * way, we can be sure that SIGTERMs are not lost we might send to the child. (Note that for
+ * FORK_DEATHSIG_SIGKILL we don't bother, since it cannot be blocked anyway.) */
+
+ assert_se(sigfillset(&ss) >= 0);
+ block_signals = block_all = true;
+
+ } else if (flags & FORK_WAIT) {
+ /* Let's block SIGCHLD at least, so that we can safely watch for the child process */
+
+ assert_se(sigemptyset(&ss) >= 0);
+ assert_se(sigaddset(&ss, SIGCHLD) >= 0);
+ block_signals = true;
+ }
+
+ if (block_signals) {
+ if (sigprocmask(SIG_SETMASK, &ss, &saved_ss) < 0)
+ return log_full_errno(prio, errno, "Failed to set signal mask: %m");
+ saved_ssp = &saved_ss;
+ }
+
+ if (FLAGS_SET(flags, FORK_DETACH)) {
+ assert(!FLAGS_SET(flags, FORK_WAIT));
+ assert(!ret_pid);
+
+ /* Fork off intermediary child if needed */
+
+ r = is_reaper_process();
+ if (r < 0)
+ return log_full_errno(prio, r, "Failed to determine if we are a reaper process: %m");
+
+ if (!r) {
+ /* Not a reaper process, hence do a double fork() so we are reparented to one */
+
+ pid = fork();
+ if (pid < 0)
+ return log_full_errno(prio, errno, "Failed to fork off '%s': %m", strna(name));
+ if (pid > 0) {
+ log_debug("Successfully forked off intermediary '%s' as PID " PID_FMT ".", strna(name), pid);
+ return 1; /* return in the parent */
+ }
+
+ intermediary = true;
+ }
+ }
+
+ if ((flags & (FORK_NEW_MOUNTNS|FORK_NEW_USERNS)) != 0)
+ pid = raw_clone(SIGCHLD|
+ (FLAGS_SET(flags, FORK_NEW_MOUNTNS) ? CLONE_NEWNS : 0) |
+ (FLAGS_SET(flags, FORK_NEW_USERNS) ? CLONE_NEWUSER : 0));
+ else
+ pid = fork();
+ if (pid < 0)
+ return log_full_errno(prio, errno, "Failed to fork off '%s': %m", strna(name));
+ if (pid > 0) {
+
+ /* If we are in the intermediary process, exit now */
+ if (intermediary)
+ _exit(EXIT_SUCCESS);
+
+ /* We are in the parent process */
+ log_debug("Successfully forked off '%s' as PID " PID_FMT ".", strna(name), pid);
+
+ if (flags & FORK_WAIT) {
+ if (block_all) {
+ /* undo everything except SIGCHLD */
+ ss = saved_ss;
+ assert_se(sigaddset(&ss, SIGCHLD) >= 0);
+ (void) sigprocmask(SIG_SETMASK, &ss, NULL);
+ }
+
+ r = wait_for_terminate_and_check(name, pid, (flags & FORK_LOG ? WAIT_LOG : 0));
+ if (r < 0)
+ return r;
+ if (r != EXIT_SUCCESS) /* exit status > 0 should be treated as failure, too */
+ return -EPROTO;
+ }
+
+ if (ret_pid)
+ *ret_pid = pid;
+
+ return 1;
+ }
+
+ /* We are in the child process */
+
+ /* Restore signal mask manually */
+ saved_ssp = NULL;
+
+ if (flags & FORK_REOPEN_LOG) {
+ /* Close the logs if requested, before we log anything. And make sure we reopen it if needed. */
+ log_close();
+ log_set_open_when_needed(true);
+ log_settle_target();
+ }
+
+ if (name) {
+ r = rename_process(name);
+ if (r < 0)
+ log_full_errno(flags & FORK_LOG ? LOG_WARNING : LOG_DEBUG,
+ r, "Failed to rename process, ignoring: %m");
+ }
+
+ if (flags & (FORK_DEATHSIG_SIGTERM|FORK_DEATHSIG_SIGINT|FORK_DEATHSIG_SIGKILL))
+ if (prctl(PR_SET_PDEATHSIG, fork_flags_to_signal(flags)) < 0) {
+ log_full_errno(prio, errno, "Failed to set death signal: %m");
+ _exit(EXIT_FAILURE);
+ }
+
+ if (flags & FORK_RESET_SIGNALS) {
+ r = reset_all_signal_handlers();
+ if (r < 0) {
+ log_full_errno(prio, r, "Failed to reset signal handlers: %m");
+ _exit(EXIT_FAILURE);
+ }
+
+ /* This implicitly undoes the signal mask stuff we did before the fork()ing above */
+ r = reset_signal_mask();
+ if (r < 0) {
+ log_full_errno(prio, r, "Failed to reset signal mask: %m");
+ _exit(EXIT_FAILURE);
+ }
+ } else if (block_signals) { /* undo what we did above */
+ if (sigprocmask(SIG_SETMASK, &saved_ss, NULL) < 0) {
+ log_full_errno(prio, errno, "Failed to restore signal mask: %m");
+ _exit(EXIT_FAILURE);
+ }
+ }
+
+ if (flags & (FORK_DEATHSIG_SIGTERM|FORK_DEATHSIG_SIGKILL|FORK_DEATHSIG_SIGINT)) {
+ pid_t ppid;
+ /* Let's see if the parent PID is still the one we started from? If not, then the parent
+ * already died by the time we set PR_SET_PDEATHSIG, hence let's emulate the effect */
+
+ ppid = getppid();
+ if (ppid == 0)
+ /* Parent is in a different PID namespace. */;
+ else if (ppid != original_pid) {
+ int sig = fork_flags_to_signal(flags);
+ log_debug("Parent died early, raising %s.", signal_to_string(sig));
+ (void) raise(sig);
+ _exit(EXIT_FAILURE);
+ }
+ }
+
+ if (FLAGS_SET(flags, FORK_NEW_MOUNTNS | FORK_MOUNTNS_SLAVE)) {
+ /* Optionally, make sure we never propagate mounts to the host. */
+ if (mount(NULL, "/", NULL, MS_SLAVE | MS_REC, NULL) < 0) {
+ log_full_errno(prio, errno, "Failed to remount root directory as MS_SLAVE: %m");
+ _exit(EXIT_FAILURE);
+ }
+ }
+
+ if (FLAGS_SET(flags, FORK_PRIVATE_TMP)) {
+ assert(FLAGS_SET(flags, FORK_NEW_MOUNTNS));
+
+ /* Optionally, overmount new tmpfs instance on /tmp/. */
+ r = mount_nofollow("tmpfs", "/tmp", "tmpfs",
+ MS_NOSUID|MS_NODEV,
+ "mode=01777" TMPFS_LIMITS_RUN);
+ if (r < 0) {
+ log_full_errno(prio, r, "Failed to overmount /tmp/: %m");
+ _exit(EXIT_FAILURE);
+ }
+ }
+
+ if (flags & FORK_REARRANGE_STDIO) {
+ if (stdio_fds) {
+ r = rearrange_stdio(stdio_fds[0], stdio_fds[1], stdio_fds[2]);
+ if (r < 0) {
+ log_full_errno(prio, r, "Failed to rearrange stdio fds: %m");
+ _exit(EXIT_FAILURE);
+ }
+ } else {
+ r = make_null_stdio();
+ if (r < 0) {
+ log_full_errno(prio, r, "Failed to connect stdin/stdout to /dev/null: %m");
+ _exit(EXIT_FAILURE);
+ }
+ }
+ } else if (flags & FORK_STDOUT_TO_STDERR) {
+ if (dup2(STDERR_FILENO, STDOUT_FILENO) < 0) {
+ log_full_errno(prio, errno, "Failed to connect stdout to stderr: %m");
+ _exit(EXIT_FAILURE);
+ }
+ }
+
+ if (flags & FORK_CLOSE_ALL_FDS) {
+ /* Close the logs here in case it got reopened above, as close_all_fds() would close them for us */
+ log_close();
+
+ r = close_all_fds(except_fds, n_except_fds);
+ if (r < 0) {
+ log_full_errno(prio, r, "Failed to close all file descriptors: %m");
+ _exit(EXIT_FAILURE);
+ }
+ }
+
+ if (flags & FORK_CLOEXEC_OFF) {
+ r = fd_cloexec_many(except_fds, n_except_fds, false);
+ if (r < 0) {
+ log_full_errno(prio, r, "Failed to turn off O_CLOEXEC on file descriptors: %m");
+ _exit(EXIT_FAILURE);
+ }
+ }
+
+ /* When we were asked to reopen the logs, do so again now */
+ if (flags & FORK_REOPEN_LOG) {
+ log_open();
+ log_set_open_when_needed(false);
+ }
+
+ if (flags & FORK_RLIMIT_NOFILE_SAFE) {
+ r = rlimit_nofile_safe();
+ if (r < 0) {
+ log_full_errno(prio, r, "Failed to lower RLIMIT_NOFILE's soft limit to 1K: %m");
+ _exit(EXIT_FAILURE);
+ }
+ }
+
+ if (!FLAGS_SET(flags, FORK_KEEP_NOTIFY_SOCKET)) {
+ r = RET_NERRNO(unsetenv("NOTIFY_SOCKET"));
+ if (r < 0) {
+ log_full_errno(prio, r, "Failed to unset $NOTIFY_SOCKET: %m");
+ _exit(EXIT_FAILURE);
+ }
+ }
+
+ if (ret_pid)
+ *ret_pid = getpid_cached();
+
+ return 0;
+}
+
+int namespace_fork(
+ const char *outer_name,
+ const char *inner_name,
+ const int except_fds[],
+ size_t n_except_fds,
+ ForkFlags flags,
+ int pidns_fd,
+ int mntns_fd,
+ int netns_fd,
+ int userns_fd,
+ int root_fd,
+ pid_t *ret_pid) {
+
+ int r;
+
+ /* This is much like safe_fork(), but forks twice, and joins the specified namespaces in the middle
+ * process. This ensures that we are fully a member of the destination namespace, with pidns an all, so that
+ * /proc/self/fd works correctly. */
+
+ r = safe_fork_full(outer_name,
+ NULL,
+ except_fds, n_except_fds,
+ (flags|FORK_DEATHSIG_SIGINT|FORK_DEATHSIG_SIGTERM|FORK_DEATHSIG_SIGKILL) & ~(FORK_REOPEN_LOG|FORK_NEW_MOUNTNS|FORK_MOUNTNS_SLAVE), ret_pid);
+ if (r < 0)
+ return r;
+ if (r == 0) {
+ pid_t pid;
+
+ /* Child */
+
+ r = namespace_enter(pidns_fd, mntns_fd, netns_fd, userns_fd, root_fd);
+ if (r < 0) {
+ log_full_errno(FLAGS_SET(flags, FORK_LOG) ? LOG_ERR : LOG_DEBUG, r, "Failed to join namespace: %m");
+ _exit(EXIT_FAILURE);
+ }
+
+ /* We mask a few flags here that either make no sense for the grandchild, or that we don't have to do again */
+ r = safe_fork_full(inner_name,
+ NULL,
+ except_fds, n_except_fds,
+ flags & ~(FORK_WAIT|FORK_RESET_SIGNALS|FORK_CLOSE_ALL_FDS|FORK_REARRANGE_STDIO), &pid);
+ if (r < 0)
+ _exit(EXIT_FAILURE);
+ if (r == 0) {
+ /* Child */
+ if (ret_pid)
+ *ret_pid = pid;
+ return 0;
+ }
+
+ r = wait_for_terminate_and_check(inner_name, pid, FLAGS_SET(flags, FORK_LOG) ? WAIT_LOG : 0);
+ if (r < 0)
+ _exit(EXIT_FAILURE);
+
+ _exit(r);
+ }
+
+ return 1;
+}
+
+int set_oom_score_adjust(int value) {
+ char t[DECIMAL_STR_MAX(int)];
+
+ xsprintf(t, "%i", value);
+
+ return write_string_file("/proc/self/oom_score_adj", t,
+ WRITE_STRING_FILE_VERIFY_ON_FAILURE|WRITE_STRING_FILE_DISABLE_BUFFER);
+}
+
+int get_oom_score_adjust(int *ret) {
+ _cleanup_free_ char *t = NULL;
+ int r, a;
+
+ r = read_virtual_file("/proc/self/oom_score_adj", SIZE_MAX, &t, NULL);
+ if (r < 0)
+ return r;
+
+ delete_trailing_chars(t, WHITESPACE);
+
+ assert_se(safe_atoi(t, &a) >= 0);
+ assert_se(oom_score_adjust_is_valid(a));
+
+ if (ret)
+ *ret = a;
+ return 0;
+}
+
+int pidfd_get_pid(int fd, pid_t *ret) {
+ char path[STRLEN("/proc/self/fdinfo/") + DECIMAL_STR_MAX(int)];
+ _cleanup_free_ char *fdinfo = NULL;
+ char *p;
+ int r;
+
+ /* Converts a pidfd into a pid. Well known errors:
+ *
+ * -EBADF → fd invalid
+ * -ENOSYS → /proc/ not mounted
+ * -ENOTTY → fd valid, but not a pidfd
+ * -EREMOTE → fd valid, but pid is in another namespace we cannot translate to the local one
+ * -ESRCH → fd valid, but process is already reaped
+ */
+
+ if (fd < 0)
+ return -EBADF;
+
+ xsprintf(path, "/proc/self/fdinfo/%i", fd);
+
+ r = read_full_virtual_file(path, &fdinfo, NULL);
+ if (r == -ENOENT) /* if fdinfo doesn't exist we assume the process does not exist */
+ return proc_mounted() > 0 ? -EBADF : -ENOSYS;
+ if (r < 0)
+ return r;
+
+ p = find_line_startswith(fdinfo, "Pid:");
+ if (!p)
+ return -ENOTTY; /* not a pidfd? */
+
+ p += strspn(p, WHITESPACE);
+ p[strcspn(p, WHITESPACE)] = 0;
+
+ if (streq(p, "0"))
+ return -EREMOTE; /* PID is in foreign PID namespace? */
+ if (streq(p, "-1"))
+ return -ESRCH; /* refers to reaped process? */
+
+ return parse_pid(p, ret);
+}
+
+int pidfd_verify_pid(int pidfd, pid_t pid) {
+ pid_t current_pid;
+ int r;
+
+ assert(pidfd >= 0);
+ assert(pid > 0);
+
+ r = pidfd_get_pid(pidfd, &current_pid);
+ if (r < 0)
+ return r;
+
+ return current_pid != pid ? -ESRCH : 0;
+}
+
+static int rlimit_to_nice(rlim_t limit) {
+ if (limit <= 1)
+ return PRIO_MAX-1; /* i.e. 19 */
+
+ if (limit >= -PRIO_MIN + PRIO_MAX)
+ return PRIO_MIN; /* i.e. -20 */
+
+ return PRIO_MAX - (int) limit;
+}
+
+int setpriority_closest(int priority) {
+ int current, limit, saved_errno;
+ struct rlimit highest;
+
+ /* Try to set requested nice level */
+ if (setpriority(PRIO_PROCESS, 0, priority) >= 0)
+ return 1;
+
+ /* Permission failed */
+ saved_errno = -errno;
+ if (!ERRNO_IS_PRIVILEGE(saved_errno))
+ return saved_errno;
+
+ errno = 0;
+ current = getpriority(PRIO_PROCESS, 0);
+ if (errno != 0)
+ return -errno;
+
+ if (priority == current)
+ return 1;
+
+ /* Hmm, we'd expect that raising the nice level from our status quo would always work. If it doesn't,
+ * then the whole setpriority() system call is blocked to us, hence let's propagate the error
+ * right-away */
+ if (priority > current)
+ return saved_errno;
+
+ if (getrlimit(RLIMIT_NICE, &highest) < 0)
+ return -errno;
+
+ limit = rlimit_to_nice(highest.rlim_cur);
+
+ /* We are already less nice than limit allows us */
+ if (current < limit) {
+ log_debug("Cannot raise nice level, permissions and the resource limit do not allow it.");
+ return 0;
+ }
+
+ /* Push to the allowed limit */
+ if (setpriority(PRIO_PROCESS, 0, limit) < 0)
+ return -errno;
+
+ log_debug("Cannot set requested nice level (%i), used next best (%i).", priority, limit);
+ return 0;
+}
+
+_noreturn_ void freeze(void) {
+ log_close();
+
+ /* Make sure nobody waits for us (i.e. on one of our sockets) anymore. Note that we use
+ * close_all_fds_without_malloc() instead of plain close_all_fds() here, since we want this function
+ * to be compatible with being called from signal handlers. */
+ (void) close_all_fds_without_malloc(NULL, 0);
+
+ /* Let's not freeze right away, but keep reaping zombies. */
+ for (;;) {
+ siginfo_t si = {};
+
+ if (waitid(P_ALL, 0, &si, WEXITED) < 0 && errno != EINTR)
+ break;
+ }
+
+ /* waitid() failed with an unexpected error, things are really borked. Freeze now! */
+ for (;;)
+ pause();
+}
+
+int get_process_threads(pid_t pid) {
+ _cleanup_free_ char *t = NULL;
+ const char *p;
+ int n, r;
+
+ if (pid < 0)
+ return -EINVAL;
+
+ p = procfs_file_alloca(pid, "status");
+
+ r = get_proc_field(p, "Threads", WHITESPACE, &t);
+ if (r == -ENOENT)
+ return proc_mounted() == 0 ? -ENOSYS : -ESRCH;
+ if (r < 0)
+ return r;
+
+ r = safe_atoi(t, &n);
+ if (r < 0)
+ return r;
+ if (n < 0)
+ return -EINVAL;
+
+ return n;
+}
+
+int is_reaper_process(void) {
+ int b = 0;
+
+ /* Checks if we are running in a reaper process, i.e. if we are expected to deal with processes
+ * reparented to us. This simply checks if we are PID 1 or if PR_SET_CHILD_SUBREAPER was called. */
+
+ if (getpid_cached() == 1)
+ return true;
+
+ if (prctl(PR_GET_CHILD_SUBREAPER, (unsigned long) &b, 0UL, 0UL, 0UL) < 0)
+ return -errno;
+
+ return b != 0;
+}
+
+int make_reaper_process(bool b) {
+
+ if (getpid_cached() == 1) {
+
+ if (!b)
+ return -EINVAL;
+
+ return 0;
+ }
+
+ /* Some prctl()s insist that all 5 arguments are specified, others do not. Let's always specify all,
+ * to avoid any ambiguities */
+ if (prctl(PR_SET_CHILD_SUBREAPER, (unsigned long) b, 0UL, 0UL, 0UL) < 0)
+ return -errno;
+
+ return 0;
+}
+
+int posix_spawn_wrapper(const char *path, char *const *argv, char *const *envp, pid_t *ret_pid) {
+ posix_spawnattr_t attr;
+ sigset_t mask;
+ pid_t pid;
+ int r;
+
+ /* Forks and invokes 'path' with 'argv' and 'envp' using CLONE_VM and CLONE_VFORK, which means the
+ * caller will be blocked until the child either exits or exec's. The memory of the child will be
+ * fully shared with the memory of the parent, so that there are no copy-on-write or memory.max
+ * issues. */
+
+ assert(path);
+ assert(argv);
+ assert(ret_pid);
+
+ assert_se(sigfillset(&mask) >= 0);
+
+ r = posix_spawnattr_init(&attr);
+ if (r != 0)
+ return -r; /* These functions return a positive errno on failure */
+ /* Set all signals to SIG_DFL */
+ r = posix_spawnattr_setflags(&attr, POSIX_SPAWN_SETSIGMASK|POSIX_SPAWN_SETSIGDEF);
+ if (r != 0)
+ goto fail;
+ r = posix_spawnattr_setsigmask(&attr, &mask);
+ if (r != 0)
+ goto fail;
+
+ r = posix_spawn(&pid, path, NULL, &attr, argv, envp);
+ if (r != 0)
+ goto fail;
+
+ *ret_pid = pid;
+
+ posix_spawnattr_destroy(&attr);
+ return 0;
+
+fail:
+ assert(r > 0);
+ posix_spawnattr_destroy(&attr);
+ return -r;
+}
+
+int proc_dir_open(DIR **ret) {
+ DIR *d;
+
+ assert(ret);
+
+ d = opendir("/proc");
+ if (!d)
+ return -errno;
+
+ *ret = d;
+ return 0;
+}
+
+int proc_dir_read(DIR *d, pid_t *ret) {
+ assert(d);
+
+ for (;;) {
+ struct dirent *de;
+
+ errno = 0;
+ de = readdir_no_dot(d);
+ if (!de) {
+ if (errno != 0)
+ return -errno;
+
+ break;
+ }
+
+ if (!IN_SET(de->d_type, DT_DIR, DT_UNKNOWN))
+ continue;
+
+ if (parse_pid(de->d_name, ret) >= 0)
+ return 1;
+ }
+
+ if (ret)
+ *ret = 0;
+ return 0;
+}
+
+int proc_dir_read_pidref(DIR *d, PidRef *ret) {
+ int r;
+
+ assert(d);
+
+ for (;;) {
+ pid_t pid;
+
+ r = proc_dir_read(d, &pid);
+ if (r < 0)
+ return r;
+ if (r == 0)
+ break;
+
+ r = pidref_set_pid(ret, pid);
+ if (r == -ESRCH) /* gone by now? skip it */
+ continue;
+ if (r < 0)
+ return r;
+
+ return 1;
+ }
+
+ if (ret)
+ *ret = PIDREF_NULL;
+ return 0;
+}
+
+static const char *const sigchld_code_table[] = {
+ [CLD_EXITED] = "exited",
+ [CLD_KILLED] = "killed",
+ [CLD_DUMPED] = "dumped",
+ [CLD_TRAPPED] = "trapped",
+ [CLD_STOPPED] = "stopped",
+ [CLD_CONTINUED] = "continued",
+};
+
+DEFINE_STRING_TABLE_LOOKUP(sigchld_code, int);
+
+static const char* const sched_policy_table[] = {
+ [SCHED_OTHER] = "other",
+ [SCHED_BATCH] = "batch",
+ [SCHED_IDLE] = "idle",
+ [SCHED_FIFO] = "fifo",
+ [SCHED_RR] = "rr",
+};
+
+DEFINE_STRING_TABLE_LOOKUP_WITH_FALLBACK(sched_policy, int, INT_MAX);
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-03 19:35:54 +0000