support/support.h

   1 /* Common extra functions.
   2    Copyright (C) 2016-2021 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <https://www.gnu.org/licenses/>.  */
  18
  19 /* This header file should only contain definitions compatible with
  20    C90.  (Using __attribute__ is fine because <features.h> provides a
  21    fallback.)  */
  22
  23 #ifndef SUPPORT_H
  24 #define SUPPORT_H
  25
  26 #include <stdbool.h>
  27 #include <stdint.h>
  28 #include <stddef.h>
  29 #include <sys/cdefs.h>
  30 /* For mode_t.  */
  31 #include <sys/stat.h>
  32 /* For ssize_t and off64_t.  */
  33 #include <sys/types.h>
  34 /* For locale_t.  */
  35 #include <locale.h>
  36
  37 __BEGIN_DECLS
  38
  39 /* Write a message to standard output.  Can be used in signal
  40    handlers.  */
  41 void write_message (const char *message) __attribute__ ((nonnull (1)));
  42
  43 /* Avoid all the buffer overflow messages on stderr.  */
  44 void ignore_stderr (void);
  45
  46 /* Set fortification error handler.  Used when tests want to verify that bad
  47    code is caught by the library.  */
  48 void set_fortify_handler (void (*handler) (int sig));
  49
  50 /* Report an out-of-memory error for the allocation of SIZE bytes in
  51    FUNCTION, terminating the process.  */
  52 void oom_error (const char *function, size_t size)
  53   __attribute__ ((nonnull (1)));
  54
  55 /* Return a pointer to a memory region of SIZE bytes.  The memory is
  56    initialized to zero and will be shared with subprocesses (across
  57    fork).  The returned pointer must be freed using
  58    support_shared_free; it is not compatible with the malloc
  59    functions.  */
  60 void *support_shared_allocate (size_t size);
  61
  62 /* Deallocate a pointer returned by support_shared_allocate.  */
  63 void support_shared_free (void *);
  64
  65 /* Write CONTENTS to the file PATH.  Create or truncate the file as
  66    needed.  The file mode is 0666 masked by the umask.  Terminate the
  67    process on error.  */
  68 void support_write_file_string (const char *path, const char *contents);
  69
  70 /* Quote the contents of the byte array starting at BLOB, of LENGTH
  71    bytes, in such a way that the result string can be included in a C
  72    literal (in single/double quotes, without putting the quotes into
  73    the result).  */
  74 char *support_quote_blob (const void *blob, size_t length);
  75
  76 /* Quote the contents of the string, in such a way that the result
  77    string can be included in a C literal (in single/double quotes,
  78    without putting the quotes into the result).  */
  79 char *support_quote_string (const char *);
  80
  81 /* Returns non-zero if the file descriptor is a regular file on a file
  82    system which supports holes (that is, seeking and writing does not
  83    allocate storage for the range of zeros).  FD must refer to a
  84    regular file open for writing, and initially empty.  */
  85 int support_descriptor_supports_holes (int fd);
  86
  87 /* Error-checking wrapper functions which terminate the process on
  88    error.  */
  89
  90 extern void *xmalloc (size_t n)
  91   __attribute_malloc__ __attribute_alloc_size__ ((1)) __attr_dealloc_free
  92   __returns_nonnull;
  93 extern void *xcalloc (size_t n, size_t s)
  94   __attribute_malloc__ __attribute_alloc_size__ ((1, 2)) __attr_dealloc_free
  95   __returns_nonnull;
  96 extern void *xrealloc (void *o, size_t n)
  97   __attribute_malloc__ __attribute_alloc_size__ ((2)) __attr_dealloc_free;
  98 extern char *xstrdup (const char *) __attribute_malloc__ __attr_dealloc_free
  99   __returns_nonnull;
 100 void *xposix_memalign (size_t alignment, size_t n)
 101   __attribute_malloc__ __attribute_alloc_size__ ((2)) __attr_dealloc_free
 102   __returns_nonnull;
 103 char *xasprintf (const char *format, ...)
 104   __attribute__ ((format (printf, 1, 2), malloc)) __attr_dealloc_free
 105   __returns_nonnull;
 106 char *xstrdup (const char *) __attr_dealloc_free __returns_nonnull;
 107 char *xstrndup (const char *, size_t) __attr_dealloc_free __returns_nonnull;
 108 char *xsetlocale (int category, const char *locale);
 109 locale_t xnewlocale (int category_mask, const char *locale, locale_t base);
 110 char *xuselocale (locale_t newloc);
 111
 112 /* These point to the TOP of the source/build tree, not your (or
 113    support's) subdirectory.  */
 114 extern const char support_srcdir_root[];
 115 extern const char support_objdir_root[];
 116
 117 /* Corresponds to the path to the runtime linker used by the testsuite,
 118    e.g. OBJDIR_PATH/elf/ld-linux-x86-64.so.2  */
 119 extern const char support_objdir_elf_ldso[];
 120
 121 /* Corresponds to the --prefix= passed to configure.  */
 122 extern const char support_install_prefix[];
 123 /* Corresponds to the install's lib/ or lib64/ directory.  */
 124 extern const char support_libdir_prefix[];
 125 /* Corresponds to the install's bin/ directory.  */
 126 extern const char support_bindir_prefix[];
 127 /* Corresponds to the install's sbin/ directory.  */
 128 extern const char support_sbindir_prefix[];
 129 /* Corresponds to the install's system /lib or /lib64 directory.  */
 130 extern const char support_slibdir_prefix[];
 131 /* Corresponds to the install's sbin/ directory (without prefix).  */
 132 extern const char support_install_rootsbindir[];
 133 /* Corresponds to the install's compiled locale directory.  */
 134 extern const char support_complocaledir_prefix[];
 135
 136 /* Copies the file at the path FROM to TO.  If TO does not exist, it
 137    is created.  If TO is a regular file, it is truncated before
 138    copying.  The file mode is copied, but the permissions are not.  */
 139 extern void support_copy_file (const char *from, const char *to);
 140
 141 extern ssize_t support_copy_file_range (int, off64_t *, int, off64_t *,
 142                                         size_t, unsigned int);
 143
 144 /* Return true if PATH supports 64-bit time_t interfaces for file
 145    operations (such as fstatat or utimensat).  */
 146 extern bool support_path_support_time64_value (const char *path, int64_t at,
 147                                                int64_t mt);
 148 static __inline bool support_path_support_time64 (const char *path)
 149 {
 150   /* 1s and 2s after y2038 limit.  */
 151   return support_path_support_time64_value (path, 0x80000001ULL,
 152                                             0x80000002ULL);
 153 }
 154
 155 /* Return true if stat supports nanoseconds resolution.  PATH is used
 156    for tests and its ctime may change.  */
 157 extern bool support_stat_nanoseconds (const char *path);
 158
 159 /* Return true if select modify the timeout to reflect the amount of time
 160    no slept.  */
 161 extern bool support_select_modifies_timeout (void);
 162
 163 /* Return true if select normalize the timeout input by taking in account
 164    tv_usec larger than 1000000.  */
 165 extern bool support_select_normalizes_timeout (void);
 166
 167 /* Create a timer that trigger after SEC seconds and NSEC nanoseconds.  If
 168    REPEAT is true the timer will repeat indefinitely.  If CALLBACK is not
 169    NULL, the function will be called when the timer expires; otherwise a
 170    dummy empty function is used instead.
 171    This is implemented with POSIX per-process timer with SIGEV_SIGNAL.  */
 172 timer_t support_create_timer (uint64_t sec, long int nsec, bool repeat,
 173                               void (*callback)(int));
 174 /* Disable the timer TIMER.  */
 175 void support_delete_timer (timer_t timer);
 176
 177 struct support_stack
 178 {
 179   void *stack;
 180   size_t size;
 181   size_t guardsize;
 182 };
 183
 184 /* Allocate stack suitable to used with xclone or sigaltstack call. The stack
 185    will have a minimum size of SIZE + MINSIGSTKSZ bytes, rounded up to a whole
 186    number of pages.  There will be a large (at least 1 MiB) inaccessible guard
 187    bands on either side of it.
 188    The returned value on ALLOC_BASE and ALLOC_SIZE will be the usable stack
 189    region, excluding the GUARD_SIZE allocated area.
 190    It also terminates the process on error.  */
 191 struct support_stack support_stack_alloc (size_t size);
 192
 193 /* Deallocate the STACK.  */
 194 void support_stack_free (struct support_stack *stack);
 195
 196 __END_DECLS
 197
 198 #endif /* SUPPORT_H */