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-rw-r--r--src/basic/process-util.c1691
1 files changed, 1691 insertions, 0 deletions
diff --git a/src/basic/process-util.c b/src/basic/process-util.c
new file mode 100644
index 0000000..35246a9
--- /dev/null
+++ b/src/basic/process-util.c
@@ -0,0 +1,1691 @@
+/* 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 <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/mman.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 "alloc-util.h"
+#include "architecture.h"
+#include "env-util.h"
+#include "errno-util.h"
+#include "escape.h"
+#include "fd-util.h"
+#include "fileio.h"
+#include "fs-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 "namespace-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 get_process_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;
+}
+
+static int get_process_cmdline_nulstr(
+ pid_t pid,
+ size_t max_size,
+ ProcessCmdlineFlags flags,
+ char **ret,
+ size_t *ret_size) {
+
+ const char *p;
+ char *t;
+ 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) {
+ t = mfree(t);
+
+ if (!(flags & PROCESS_CMDLINE_COMM_FALLBACK))
+ return -ENOENT;
+
+ /* Kernel threads have no argv[] */
+ _cleanup_free_ char *comm = NULL;
+
+ r = get_process_comm(pid, &comm);
+ if (r < 0)
+ return r;
+
+ t = strjoin("[", comm, "]");
+ if (!t)
+ return -ENOMEM;
+
+ k = strlen(t);
+ r = k <= max_size;
+ if (r == 0) /* truncation */
+ t[max_size] = '\0';
+ }
+
+ *ret = t;
+ *ret_size = k;
+ return r;
+}
+
+int get_process_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 commandline. 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 = get_process_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;
+
+ args = strv_parse_nulstr(t, k);
+ if (!args)
+ return -ENOMEM;
+
+ /* Drop trailing empty strings. See issue #21186. */
+ STRV_FOREACH_BACKWARDS(p, args) {
+ if (!isempty(*p))
+ break;
+
+ *p = mfree(*p);
+ }
+
+ 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;
+}
+
+static int update_argv(const char name[], size_t l) {
+ static int can_do = -1;
+
+ if (can_do == 0)
+ return 0;
+ can_do = false; /* We'll set it to true only if the whole process works */
+
+ /* Let's not bother with this if we don't have euid == 0. Strictly speaking we should check for the
+ * CAP_SYS_RESOURCE capability which is independent of the euid. In our own code the capability generally is
+ * present only for euid == 0, hence let's use this as quick bypass check, to avoid calling mmap() if
+ * PR_SET_MM_ARG_{START,END} fails with EPERM later on anyway. After all geteuid() is dead cheap to call, but
+ * mmap() is not. */
+ if (geteuid() != 0)
+ return log_debug_errno(SYNTHETIC_ERRNO(EPERM),
+ "Skipping PR_SET_MM, as we don't have privileges.");
+
+ static size_t mm_size = 0;
+ static char *mm = NULL;
+ int r;
+
+ if (mm_size < l+1) {
+ size_t nn_size;
+ char *nn;
+
+ nn_size = PAGE_ALIGN(l+1);
+ nn = mmap(NULL, nn_size, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
+ if (nn == MAP_FAILED)
+ return log_debug_errno(errno, "mmap() failed: %m");
+
+ strncpy(nn, name, nn_size);
+
+ /* Now, let's tell the kernel about this new memory */
+ if (prctl(PR_SET_MM, PR_SET_MM_ARG_START, (unsigned long) nn, 0, 0) < 0) {
+ if (ERRNO_IS_PRIVILEGE(errno))
+ return log_debug_errno(errno, "PR_SET_MM_ARG_START failed: %m");
+
+ /* HACK: prctl() API is kind of dumb on this point. The existing end address may already be
+ * below the desired start address, in which case the kernel may have kicked this back due
+ * to a range-check failure (see linux/kernel/sys.c:validate_prctl_map() to see this in
+ * action). The proper solution would be to have a prctl() API that could set both start+end
+ * simultaneously, or at least let us query the existing address to anticipate this condition
+ * and respond accordingly. For now, we can only guess at the cause of this failure and try
+ * a workaround--which will briefly expand the arg space to something potentially huge before
+ * resizing it to what we want. */
+ log_debug_errno(errno, "PR_SET_MM_ARG_START failed, attempting PR_SET_MM_ARG_END hack: %m");
+
+ if (prctl(PR_SET_MM, PR_SET_MM_ARG_END, (unsigned long) nn + l + 1, 0, 0) < 0) {
+ r = log_debug_errno(errno, "PR_SET_MM_ARG_END hack failed, proceeding without: %m");
+ (void) munmap(nn, nn_size);
+ return r;
+ }
+
+ if (prctl(PR_SET_MM, PR_SET_MM_ARG_START, (unsigned long) nn, 0, 0) < 0)
+ return log_debug_errno(errno, "PR_SET_MM_ARG_START still failed, proceeding without: %m");
+ } else {
+ /* And update the end pointer to the new end, too. If this fails, we don't really know what
+ * to do, it's pretty unlikely that we can rollback, hence we'll just accept the failure,
+ * and continue. */
+ if (prctl(PR_SET_MM, PR_SET_MM_ARG_END, (unsigned long) nn + l + 1, 0, 0) < 0)
+ log_debug_errno(errno, "PR_SET_MM_ARG_END failed, proceeding without: %m");
+ }
+
+ if (mm)
+ (void) munmap(mm, mm_size);
+
+ mm = nn;
+ mm_size = nn_size;
+ } else {
+ strncpy(mm, name, mm_size);
+
+ /* Update the end pointer, continuing regardless of any failure. */
+ if (prctl(PR_SET_MM, PR_SET_MM_ARG_END, (unsigned long) mm + l + 1, 0, 0) < 0)
+ log_debug_errno(errno, "PR_SET_MM_ARG_END failed, proceeding without: %m");
+ }
+
+ can_do = true;
+ return 0;
+}
+
+int rename_process(const char name[]) {
+ bool truncated = false;
+
+ /* This is a like a poor man's setproctitle(). It changes the comm field, argv[0], and also the glibc's
+ * internally used name of the process. For the first one a limit of 16 chars applies; to the second one in
+ * many cases one of 10 (i.e. length of "/sbin/init") — however if we have CAP_SYS_RESOURCES it is unbounded;
+ * to the third one 7 (i.e. the length of "systemd". If you pass a longer string it will likely be
+ * truncated.
+ *
+ * Returns 0 if a name was set but truncated, > 0 if it was set but not truncated. */
+
+ if (isempty(name))
+ return -EINVAL; /* let's not confuse users unnecessarily with an empty name */
+
+ if (!is_main_thread())
+ return -EPERM; /* Let's not allow setting the process name from other threads than the main one, as we
+ * cache things without locking, and we make assumptions that PR_SET_NAME sets the
+ * process name that isn't correct on any other threads */
+
+ size_t l = strlen(name);
+
+ /* First step, change the comm field. The main thread's comm is identical to the process comm. This means we
+ * can use PR_SET_NAME, which sets the thread name for the calling thread. */
+ if (prctl(PR_SET_NAME, name) < 0)
+ log_debug_errno(errno, "PR_SET_NAME failed: %m");
+ if (l >= TASK_COMM_LEN) /* Linux userspace process names can be 15 chars at max */
+ truncated = true;
+
+ /* Second step, change glibc's ID of the process name. */
+ if (program_invocation_name) {
+ size_t k;
+
+ k = strlen(program_invocation_name);
+ strncpy(program_invocation_name, name, k);
+ if (l > k)
+ truncated = true;
+
+ /* Also update the short name. */
+ char *p = strrchr(program_invocation_name, '/');
+ program_invocation_short_name = p ? p + 1 : program_invocation_name;
+ }
+
+ /* Third step, completely replace the argv[] array the kernel maintains for us. This requires privileges, but
+ * has the advantage that the argv[] array is exactly what we want it to be, and not filled up with zeros at
+ * the end. This is the best option for changing /proc/self/cmdline. */
+ (void) update_argv(name, l);
+
+ /* Fourth step: in all cases we'll also update the original argv[], so that our own code gets it right too if
+ * it still looks here */
+ if (saved_argc > 0) {
+ if (saved_argv[0]) {
+ size_t k;
+
+ k = strlen(saved_argv[0]);
+ strncpy(saved_argv[0], name, k);
+ if (l > k)
+ truncated = true;
+ }
+
+ for (int i = 1; i < saved_argc; i++) {
+ if (!saved_argv[i])
+ break;
+
+ memzero(saved_argv[i], strlen(saved_argv[i]));
+ }
+ }
+
+ return !truncated;
+}
+
+int 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 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_line(f, LONG_LINE_MAX, &line);
+ if (r < 0)
+ return r;
+ if (r == 0)
+ break;
+
+ l = strstrip(line);
+
+ if (startswith(l, field)) {
+ l += strlen(field);
+ l += strspn(l, WHITESPACE);
+
+ l[strcspn(l, WHITESPACE)] = 0;
+
+ return parse_uid(l, ret);
+ }
+ }
+
+ return -EIO;
+}
+
+int get_process_uid(pid_t pid, uid_t *ret) {
+
+ if (pid == 0 || pid == getpid_cached()) {
+ *ret = getuid();
+ return 0;
+ }
+
+ return get_process_id(pid, "Uid:", ret);
+}
+
+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;
+
+ 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 = get_process_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);
+}
+
+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 <= 1)
+ return false;
+
+ r = get_process_ppid(pid, &ppid);
+ if (r < 0)
+ return r;
+
+ return ppid == getpid_cached();
+}
+
+bool pid_is_unwaited(pid_t pid) {
+ /* Checks whether a PID is still valid at all, including a zombie */
+
+ if (pid < 0)
+ return false;
+
+ 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;
+}
+
+bool pid_is_alive(pid_t pid) {
+ int r;
+
+ /* Checks whether a PID is still valid and not a zombie */
+
+ if (pid < 0)
+ return false;
+
+ 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 (IN_SET(r, -ESRCH, 'Z'))
+ return false;
+
+ return true;
+}
+
+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 files_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_emergency_errno(errno, "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
+ */
+
+ __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);
+}
+
+int safe_fork_full(
+ const char *name,
+ 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;
+ int prio, r;
+
+ /* 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)) {
+ /* 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. */
+
+ 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 & (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) {
+ /* 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|FORK_DEATHSIG_SIGINT))
+ if (prctl(PR_SET_PDEATHSIG, (flags & FORK_DEATHSIG_SIGINT) ? SIGINT : SIGTERM) < 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) {
+ 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) {
+ log_debug("Parent died early, raising SIGTERM.");
+ (void) raise(SIGTERM);
+ _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 & 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_NULL_STDIO) {
+ 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_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 (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, except_fds, n_except_fds, (flags|FORK_DEATHSIG) & ~(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, except_fds, n_except_fds, flags & ~(FORK_WAIT|FORK_RESET_SIGNALS|FORK_CLOSE_ALL_FDS|FORK_NULL_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;
+
+ 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 -ESRCH;
+ if (r < 0)
+ return r;
+
+ p = startswith(fdinfo, "Pid:");
+ if (!p) {
+ p = strstr(fdinfo, "\nPid:");
+ if (!p)
+ return -ENOTTY; /* not a pidfd? */
+
+ p += 5;
+ }
+
+ p += strspn(p, WHITESPACE);
+ p[strcspn(p, WHITESPACE)] = 0;
+
+ return parse_pid(p, ret);
+}
+
+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;
+}
+
+bool invoked_as(char *argv[], const char *token) {
+ if (!argv || isempty(argv[0]))
+ return false;
+
+ if (isempty(token))
+ return false;
+
+ return strstr(last_path_component(argv[0]), token);
+}
+
+bool invoked_by_systemd(void) {
+ int r;
+
+ /* If the process is directly executed by PID1 (e.g. ExecStart= or generator), systemd-importd,
+ * or systemd-homed, then $SYSTEMD_EXEC_PID= is set, and read the command line. */
+ const char *e = getenv("SYSTEMD_EXEC_PID");
+ if (!e)
+ return false;
+
+ if (streq(e, "*"))
+ /* For testing. */
+ return true;
+
+ pid_t p;
+ r = parse_pid(e, &p);
+ if (r < 0) {
+ /* We know that systemd sets the variable correctly. Something else must have set it. */
+ log_debug_errno(r, "Failed to parse \"SYSTEMD_EXEC_PID=%s\", ignoring: %m", e);
+ return false;
+ }
+
+ return getpid_cached() == p;
+}
+
+_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();
+}
+
+bool argv_looks_like_help(int argc, char **argv) {
+ char **l;
+
+ /* Scans the command line for indications the user asks for help. This is supposed to be called by
+ * tools that do not implement getopt() style command line parsing because they are not primarily
+ * user-facing. Detects four ways of asking for help:
+ *
+ * 1. Passing zero arguments
+ * 2. Passing "help" as first argument
+ * 3. Passing --help as any argument
+ * 4. Passing -h as any argument
+ */
+
+ if (argc <= 1)
+ return true;
+
+ if (streq_ptr(argv[1], "help"))
+ return true;
+
+ l = strv_skip(argv, 1);
+
+ return strv_contains(l, "--help") ||
+ strv_contains(l, "-h");
+}
+
+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 2024-05-19 16:17:01 +0000