basic/missing: move syscall definitions to basic/missing_syscall.h

We have a bunch of syscall wrapper definitions and it's easier to
see that they follow the same pattern if they are not interspersed
with other defines.

Change the wrappers to be uniform:
- if __NR_XXX is not defined, do not bother to call the syscall,
  and return -1/ENOSYS immediately.
- do not check __NR_XXX defines if we detect the symbol as defined,
  since we don't need them anyway
- reindent stuff for readability

New file basic/missing_syscall.h is included at the end of missing.h
because it might make use of some of the definitions in missing.h.

diff --git a/src/basic/missing_syscall.h b/src/basic/missing_syscall.h
new file mode 100644 (file)
index 0000000..42c39ee
--- /dev/null
+++ b/src/basic/missing_syscall.h
@@ -0,0 +1,310 @@
+#pragma once
+
+/***
+  This file is part of elogind.
+
+  Copyright 2010 Lennart Poettering
+  Copyright 2016 Zbigniew Jędrzejewski-Szmek
+
+  elogind is free software; you can redistribute it and/or modify it
+  under the terms of the GNU Lesser General Public License as published by
+  the Free Software Foundation; either version 2.1 of the License, or
+  (at your option) any later version.
+
+  elogind is distributed in the hope that it will be useful, but
+  WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+  Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public License
+  along with elogind; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+/* Missing glibc definitions to access certain kernel APIs */
+
+#if !HAVE_DECL_PIVOT_ROOT
+static inline int pivot_root(const char *new_root, const char *put_old) {
+        return syscall(SYS_pivot_root, new_root, put_old);
+}
+#endif
+
+/* ======================================================================= */
+
+#if !HAVE_DECL_MEMFD_CREATE
+#  ifndef __NR_memfd_create
+#    if defined __x86_64__
+#      define __NR_memfd_create 319
+#    elif defined __arm__
+#      define __NR_memfd_create 385
+#    elif defined __aarch64__
+#      define __NR_memfd_create 279
+#    elif defined __s390__
+#      define __NR_memfd_create 350
+#    elif defined _MIPS_SIM
+#      if _MIPS_SIM == _MIPS_SIM_ABI32
+#        define __NR_memfd_create 4354
+#      endif
+#      if _MIPS_SIM == _MIPS_SIM_NABI32
+#        define __NR_memfd_create 6318
+#      endif
+#      if _MIPS_SIM == _MIPS_SIM_ABI64
+#        define __NR_memfd_create 5314
+#      endif
+#    elif defined __i386__
+#      define __NR_memfd_create 356
+#    else
+#      warning "__NR_memfd_create unknown for your architecture"
+#    endif
+#  endif
+
+static inline int memfd_create(const char *name, unsigned int flags) {
+#  ifdef __NR_memfd_create
+        return syscall(__NR_memfd_create, name, flags);
+#  else
+        errno = ENOSYS;
+        return -1;
+#  endif
+}
+#endif
+
+/* ======================================================================= */
+
+#if !HAVE_DECL_GETRANDOM
+#  ifndef __NR_getrandom
+#    if defined __x86_64__
+#      define __NR_getrandom 318
+#    elif defined(__i386__)
+#      define __NR_getrandom 355
+#    elif defined(__arm__)
+#      define __NR_getrandom 384
+#   elif defined(__aarch64__)
+#      define __NR_getrandom 278
+#    elif defined(__ia64__)
+#      define __NR_getrandom 1339
+#    elif defined(__m68k__)
+#      define __NR_getrandom 352
+#    elif defined(__s390x__)
+#      define __NR_getrandom 349
+#    elif defined(__powerpc__)
+#      define __NR_getrandom 359
+#    elif defined _MIPS_SIM
+#      if _MIPS_SIM == _MIPS_SIM_ABI32
+#        define __NR_getrandom 4353
+#      endif
+#      if _MIPS_SIM == _MIPS_SIM_NABI32
+#        define __NR_getrandom 6317
+#      endif
+#      if _MIPS_SIM == _MIPS_SIM_ABI64
+#        define __NR_getrandom 5313
+#      endif
+#    else
+#      warning "__NR_getrandom unknown for your architecture"
+#    endif
+#  endif
+
+static inline int getrandom(void *buffer, size_t count, unsigned flags) {
+#  ifdef __NR_getrandom
+        return syscall(__NR_getrandom, buffer, count, flags);
+#  else
+        errno = ENOSYS;
+        return -1;
+#  endif
+}
+#endif
+
+/* ======================================================================= */
+
+#if !HAVE_DECL_GETTID
+static inline pid_t gettid(void) {
+        return (pid_t) syscall(SYS_gettid);
+}
+#endif
+
+/* ======================================================================= */
+
+#if !HAVE_DECL_NAME_TO_HANDLE_AT
+#  ifndef __NR_name_to_handle_at
+#    if defined(__x86_64__)
+#      define __NR_name_to_handle_at 303
+#    elif defined(__i386__)
+#      define __NR_name_to_handle_at 341
+#    elif defined(__arm__)
+#      define __NR_name_to_handle_at 370
+#    elif defined(__powerpc__)
+#      define __NR_name_to_handle_at 345
+#    else
+#      error "__NR_name_to_handle_at is not defined"
+#    endif
+#  endif
+
+struct file_handle {
+        unsigned int handle_bytes;
+        int handle_type;
+        unsigned char f_handle[0];
+};
+
+static inline int name_to_handle_at(int fd, const char *name, struct file_handle *handle, int *mnt_id, int flags) {
+#  ifdef __NR_name_to_handle_at
+        return syscall(__NR_name_to_handle_at, fd, name, handle, mnt_id, flags);
+#  else
+        errno = ENOSYS;
+        return -1;
+#  endif
+}
+#endif
+
+/* ======================================================================= */
+
+#if !HAVE_DECL_SETNS
+#  ifndef __NR_setns
+#    if defined(__x86_64__)
+#      define __NR_setns 308
+#    elif defined(__i386__)
+#      define __NR_setns 346
+#    else
+#      error "__NR_setns is not defined"
+#    endif
+#  endif
+
+static inline int setns(int fd, int nstype) {
+#  ifdef __NR_setns
+        return syscall(__NR_setns, fd, nstype);
+#  else
+        errno = ENOSYS;
+        return -1;
+#  endif
+}
+#endif
+
+/* ======================================================================= */
+
+static inline int raw_clone(unsigned long flags, void *child_stack) {
+#if defined(__s390__) || defined(__CRIS__)
+        /* On s390 and cris the order of the first and second arguments
+         * of the raw clone() system call is reversed. */
+        return (int) syscall(__NR_clone, child_stack, flags);
+#else
+        return (int) syscall(__NR_clone, flags, child_stack);
+#endif
+}
+
+/* ======================================================================= */
+
+static inline pid_t raw_getpid(void) {
+#if defined(__alpha__)
+        return (pid_t) syscall(__NR_getxpid);
+#else
+        return (pid_t) syscall(__NR_getpid);
+#endif
+}
+
+/* ======================================================================= */
+
+#if !HAVE_DECL_RENAMEAT2
+#  ifndef __NR_renameat2
+#    if defined __x86_64__
+#      define __NR_renameat2 316
+#    elif defined __arm__
+#      define __NR_renameat2 382
+#    elif defined _MIPS_SIM
+#      if _MIPS_SIM == _MIPS_SIM_ABI32
+#        define __NR_renameat2 4351
+#      endif
+#      if _MIPS_SIM == _MIPS_SIM_NABI32
+#        define __NR_renameat2 6315
+#      endif
+#      if _MIPS_SIM == _MIPS_SIM_ABI64
+#        define __NR_renameat2 5311
+#      endif
+#    elif defined __i386__
+#      define __NR_renameat2 353
+#    else
+#      warning "__NR_renameat2 unknown for your architecture"
+#    endif
+#  endif
+
+static inline int renameat2(int oldfd, const char *oldname, int newfd, const char *newname, unsigned flags) {
+#  ifdef __NR_renameat2
+        return syscall(__NR_renameat2, oldfd, oldname, newfd, newname, flags);
+#  else
+        errno = ENOSYS;
+        return -1;
+#  endif
+}
+#endif
+
+/* ======================================================================= */
+
+#if !HAVE_DECL_KCMP
+static inline int kcmp(pid_t pid1, pid_t pid2, int type, unsigned long idx1, unsigned long idx2) {
+#  ifdef __NR_kcmp
+        return syscall(__NR_kcmp, pid1, pid2, type, idx1, idx2);
+#  else
+        errno = ENOSYS;
+        return -1;
+#  endif
+}
+#endif
+
+/* ======================================================================= */
+
+#if !HAVE_DECL_KEYCTL
+static inline long keyctl(int cmd, unsigned long arg2, unsigned long arg3, unsigned long arg4,unsigned long arg5) {
+#  ifdef __NR_keyctl
+        return syscall(__NR_keyctl, cmd, arg2, arg3, arg4, arg5);
+#  else
+        errno = ENOSYS;
+        return -1;
+#  endif
+}
+
+static inline key_serial_t add_key(const char *type, const char *description, const void *payload, size_t plen, key_serial_t ringid) {
+#  ifdef __NR_add_key
+        return syscall(__NR_add_key, type, description, payload, plen, ringid);
+#  else
+        errno = ENOSYS;
+        return -1;
+#  endif
+}
+
+static inline key_serial_t request_key(const char *type, const char *description, const char * callout_info, key_serial_t destringid) {
+#  ifdef __NR_request_key
+        return syscall(__NR_request_key, type, description, callout_info, destringid);
+#  else
+        errno = ENOSYS;
+        return -1;
+#  endif
+}
+#endif
+
+/* ======================================================================= */
+
+#if !HAVE_DECL_COPY_FILE_RANGE
+#  ifndef __NR_copy_file_range
+#    if defined(__x86_64__)
+#      define __NR_copy_file_range 326
+#    elif defined(__i386__)
+#      define __NR_copy_file_range 377
+#    elif defined __s390__
+#      define __NR_copy_file_range 375
+#    elif defined __arm__
+#      define __NR_copy_file_range 391
+#    elif defined __aarch64__
+#      define __NR_copy_file_range 285
+#    else
+#      warning "__NR_copy_file_range not defined for your architecture"
+#    endif
+#  endif
+
+static inline ssize_t copy_file_range(int fd_in, loff_t *off_in,
+                                      int fd_out, loff_t *off_out,
+                                      size_t len,
+                                      unsigned int flags) {
+#  ifdef __NR_copy_file_range
+        return syscall(__NR_copy_file_range, fd_in, off_in, fd_out, off_out, len, flags);
+#  else
+        errno = ENOSYS;
+        return -1;
+#  endif
+}
+#endif