glibc/support/support.h

/* Common extra functions.
   Copyright (C) 2016-2021 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   The GNU C Library 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.

   The GNU C Library 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 the GNU C Library; if not, see
   <https://www.gnu.org/licenses/>.  */

/* This header file should only contain definitions compatible with
   C90.  (Using __attribute__ is fine because <features.h> provides a
   fallback.)  */

#ifndef SUPPORT_H
#define SUPPORT_H

#include <stdbool.h>
#include <stddef.h>
#include <sys/cdefs.h>
/* For mode_t.  */
#include <sys/stat.h>
/* For ssize_t and off64_t.  */
#include <sys/types.h>
/* For locale_t.  */
#include <locale.h>

__BEGIN_DECLS

/* Write a message to standard output.  Can be used in signal
   handlers.  */
void write_message (const char *message) __attribute__ ((nonnull (1)));

/* Avoid all the buffer overflow messages on stderr.  */
void ignore_stderr (void);

/* Set fortification error handler.  Used when tests want to verify that bad
   code is caught by the library.  */
void set_fortify_handler (void (*handler) (int sig));

/* Report an out-of-memory error for the allocation of SIZE bytes in
   FUNCTION, terminating the process.  */
void oom_error (const char *function, size_t size)
  __attribute__ ((nonnull (1)));

/* Return a pointer to a memory region of SIZE bytes.  The memory is
   initialized to zero and will be shared with subprocesses (across
   fork).  The returned pointer must be freed using
   support_shared_free; it is not compatible with the malloc
   functions.  */
void *support_shared_allocate (size_t size);

/* Deallocate a pointer returned by support_shared_allocate.  */
void support_shared_free (void *);

/* Write CONTENTS to the file PATH.  Create or truncate the file as
   needed.  The file mode is 0666 masked by the umask.  Terminate the
   process on error.  */
void support_write_file_string (const char *path, const char *contents);

/* Quote the contents of the byte array starting at BLOB, of LENGTH
   bytes, in such a way that the result string can be included in a C
   literal (in single/double quotes, without putting the quotes into
   the result).  */
char *support_quote_blob (const void *blob, size_t length);

/* Quote the contents of the string, in such a way that the result
   string can be included in a C literal (in single/double quotes,
   without putting the quotes into the result).  */
char *support_quote_string (const char *);

/* Returns non-zero if the file descriptor is a regular file on a file
   system which supports holes (that is, seeking and writing does not
   allocate storage for the range of zeros).  FD must refer to a
   regular file open for writing, and initially empty.  */
int support_descriptor_supports_holes (int fd);

/* Error-checking wrapper functions which terminate the process on
   error.  */

void *xmalloc (size_t) __attribute__ ((malloc));
void *xcalloc (size_t n, size_t s) __attribute__ ((malloc));
void *xrealloc (void *p, size_t n);
void *xposix_memalign (size_t alignment, size_t n);
char *xasprintf (const char *format, ...)
  __attribute__ ((format (printf, 1, 2), malloc));
char *xstrdup (const char *);
char *xstrndup (const char *, size_t);
char *xsetlocale (int category, const char *locale);
locale_t xnewlocale (int category_mask, const char *locale, locale_t base);
char *xuselocale (locale_t newloc);

/* These point to the TOP of the source/build tree, not your (or
   support's) subdirectory.  */
extern const char support_srcdir_root[];
extern const char support_objdir_root[];

/* Corresponds to the path to the runtime linker used by the testsuite,
   e.g. OBJDIR_PATH/elf/ld-linux-x86-64.so.2  */
extern const char support_objdir_elf_ldso[];

/* Corresponds to the --prefix= passed to configure.  */
extern const char support_install_prefix[];
/* Corresponds to the install's lib/ or lib64/ directory.  */
extern const char support_libdir_prefix[];
/* Corresponds to the install's bin/ directory.  */
extern const char support_bindir_prefix[];
/* Corresponds to the install's sbin/ directory.  */
extern const char support_sbindir_prefix[];
/* Corresponds to the install's system /lib or /lib64 directory.  */
extern const char support_slibdir_prefix[];
/* Corresponds to the install's sbin/ directory (without prefix).  */
extern const char support_install_rootsbindir[];
/* Corresponds to the install's compiled locale directory.  */
extern const char support_complocaledir_prefix[];

/* Copies the file at the path FROM to TO.  If TO does not exist, it
   is created.  If TO is a regular file, it is truncated before
   copying.  The file mode is copied, but the permissions are not.  */
extern void support_copy_file (const char *from, const char *to);

extern ssize_t support_copy_file_range (int, off64_t *, int, off64_t *,
					size_t, unsigned int);

/* Return true if PATH supports 64-bit time_t interfaces for file
   operations (such as fstatat or utimensat).  */
extern bool support_path_support_time64_value (const char *path, int64_t at,
					       int64_t mt);
static __inline bool support_path_support_time64 (const char *path)
{
  /* 1s and 2s after y2038 limit.  */
  return support_path_support_time64_value (path, 0x80000001ULL,
					    0x80000002ULL);
}

/* Return true if stat supports nanoseconds resolution.  */
extern bool support_stat_nanoseconds (const char *path);

/* Return true if select modify the timeout to reflect the amount of time
   no slept.  */
extern bool support_select_modifies_timeout (void);

/* Return true if select normalize the timeout input by taking in account
   tv_usec larger than 1000000.  */
extern bool support_select_normalizes_timeout (void);

__END_DECLS

#endif /* SUPPORT_H */