process-util: extract pidfd-related funcs into pidfd-util.[ch]

src/basic/meson.build

@@ -72,6 +72,7 @@ basic_sources = files(
         'parse-util.c',
         'path-util.c',
         'percent-util.c',
+        'pidfd-util.c',
         'pidref.c',
         'prioq.c',
         'proc-cmdline.c',

src/basic/pidfd-util.c

@@ -0,0 +1,66 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <unistd.h>
+
+#include "errno-util.h"
+#include "fd-util.h"
+#include "fileio.h"
+#include "macro.h"
+#include "memory-util.h"
+#include "parse-util.h"
+#include "path-util.h"
+#include "pidfd-util.h"
+#include "string-util.h"
+
+int pidfd_get_pid(int fd, pid_t *ret) {
+        char path[STRLEN("/proc/self/fdinfo/") + DECIMAL_STR_MAX(int)];
+        _cleanup_free_ char *fdinfo = NULL;
+        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
+         */
+
+        assert(fd >= 0);
+
+        xsprintf(path, "/proc/self/fdinfo/%i", fd);
+
+        r = read_full_virtual_file(path, &fdinfo, NULL);
+        if (r == -ENOENT)
+                return proc_fd_enoent_errno();
+        if (r < 0)
+                return r;
+
+        char *p = find_line_startswith(fdinfo, "Pid:");
+        if (!p)
+                return -ENOTTY; /* not a pidfd? */
+
+        p = skip_leading_chars(p, /* bad = */ NULL);
+        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;
+}

src/basic/pidfd-util.h

@@ -0,0 +1,13 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+#pragma once
+
+#include <stdint.h>
+#if HAVE_PIDFD_OPEN
+#include <sys/pidfd.h>
+#endif
+#include <sys/types.h>
+
+#include "missing_syscall.h"
+
+int pidfd_get_pid(int fd, pid_t *ret);
+int pidfd_verify_pid(int pidfd, pid_t pid);

src/basic/pidref.c

@@ -1,15 +1,12 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
-#if HAVE_PIDFD_OPEN
-#include <sys/pidfd.h>
-#endif
-
 #include "errno-util.h"
 #include "fd-util.h"
 #include "missing_magic.h"
 #include "missing_syscall.h"
 #include "missing_wait.h"
 #include "parse-util.h"
+#include "pidfd-util.h"
 #include "pidref.h"
 #include "process-util.h"
 #include "signal-util.h"

src/basic/process-util.c

@@ -1859,59 +1859,6 @@ int get_oom_score_adjust(int *ret) {
         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;
-        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
-         */
-
-        assert(fd >= 0);
-
-        xsprintf(path, "/proc/self/fdinfo/%i", fd);
-
-        r = read_full_virtual_file(path, &fdinfo, NULL);
-        if (r == -ENOENT)
-                return proc_fd_enoent_errno();
-        if (r < 0)
-                return r;
-
-        char *p = find_line_startswith(fdinfo, "Pid:");
-        if (!p)
-                return -ENOTTY; /* not a pidfd? */
-
-        p = skip_leading_chars(p, /* bad = */ NULL);
-        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 */

src/basic/process-util.h

@@ -250,9 +250,6 @@ assert_cc(TASKS_MAX <= (unsigned long) PID_T_MAX);
 /* Like TAKE_PTR() but for pid_t, resetting them to 0 */
 #define TAKE_PID(pid) TAKE_GENERIC(pid, pid_t, 0)
 
-int pidfd_get_pid(int fd, pid_t *ret);
-int pidfd_verify_pid(int pidfd, pid_t pid);
-
 int setpriority_closest(int priority);
 
 _noreturn_ void freeze(void);