support/support.h

   1 /* Common extra functions.
   2    Copyright (C) 2016-2021 Free Software Foundation, Inc.
   3    Copyright The GNU Toolchain Authors.
   4    This file is part of the GNU C Library.
   5
   6    The GNU C Library is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU Lesser General Public
   8    License as published by the Free Software Foundation; either
   9    version 2.1 of the License, or (at your option) any later version.
  10
  11    The GNU C Library is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14    Lesser General Public License for more details.
  15
  16    You should have received a copy of the GNU Lesser General Public
  17    License along with the GNU C Library; if not, see
  18    <https://www.gnu.org/licenses/>.  */
  19
  20 /* This header file should only contain definitions compatible with
  21    C90.  (Using __attribute__ is fine because <features.h> provides a
  22    fallback.)  */
  23
  24 #ifndef SUPPORT_H
  25 #define SUPPORT_H
  26
  27 #include <stdbool.h>
  28 #include <stdint.h>
  29 #include <stddef.h>
  30 #include <sys/cdefs.h>
  31 /* For mode_t.  */
  32 #include <sys/stat.h>
  33 /* For ssize_t and off64_t.  */
  34 #include <sys/types.h>
  35 /* For locale_t.  */
  36 #include <locale.h>
  37
  38 __BEGIN_DECLS
  39
  40 /* Write a message to standard output.  Can be used in signal
  41    handlers.  */
  42 void write_message (const char *message) __attribute__ ((nonnull (1)));
  43
  44 /* Avoid all the buffer overflow messages on stderr.  */
  45 void ignore_stderr (void);
  46
  47 /* Set fortification error handler.  Used when tests want to verify that bad
  48    code is caught by the library.  */
  49 void set_fortify_handler (void (*handler) (int sig));
  50
  51 /* Report an out-of-memory error for the allocation of SIZE bytes in
  52    FUNCTION, terminating the process.  */
  53 void oom_error (const char *function, size_t size)
  54   __attribute__ ((nonnull (1)));
  55
  56 /* Return a pointer to a memory region of SIZE bytes.  The memory is
  57    initialized to zero and will be shared with subprocesses (across
  58    fork).  The returned pointer must be freed using
  59    support_shared_free; it is not compatible with the malloc
  60    functions.  */
  61 void *support_shared_allocate (size_t size);
  62
  63 /* Deallocate a pointer returned by support_shared_allocate.  */
  64 void support_shared_free (void *);
  65
  66 /* Write CONTENTS to the file PATH.  Create or truncate the file as
  67    needed.  The file mode is 0666 masked by the umask.  Terminate the
  68    process on error.  */
  69 void support_write_file_string (const char *path, const char *contents);
  70
  71 /* Quote the contents of the byte array starting at BLOB, of LENGTH
  72    bytes, in such a way that the result string can be included in a C
  73    literal (in single/double quotes, without putting the quotes into
  74    the result).  */
  75 char *support_quote_blob (const void *blob, size_t length);
  76
  77 /* Quote the contents of the wide character array starting at BLOB, of
  78    LENGTH wide characters, in such a way that the result string can be
  79    included in a C wide string literal (in single/double quotes,
  80    without putting the quotes into the result).  */
  81 char *support_quote_blob_wide (const void *blob, size_t length);
  82
  83 /* Quote the contents of the string, in such a way that the result
  84    string can be included in a C literal (in single/double quotes,
  85    without putting the quotes into the result).  */
  86 char *support_quote_string (const char *);
  87
  88 /* Returns non-zero if the file descriptor is a regular file on a file
  89    system which supports holes (that is, seeking and writing does not
  90    allocate storage for the range of zeros).  FD must refer to a
  91    regular file open for writing, and initially empty.  */
  92 int support_descriptor_supports_holes (int fd);
  93
  94 /* Error-checking wrapper functions which terminate the process on
  95    error.  */
  96
  97 extern void *xmalloc (size_t n)
  98   __attribute_malloc__ __attribute_alloc_size__ ((1)) __attr_dealloc_free
  99   __returns_nonnull;
 100 extern void *xcalloc (size_t n, size_t s)
 101   __attribute_malloc__ __attribute_alloc_size__ ((1, 2)) __attr_dealloc_free
 102   __returns_nonnull;
 103 extern void *xrealloc (void *o, size_t n)
 104   __attribute_malloc__ __attribute_alloc_size__ ((2)) __attr_dealloc_free;
 105 extern char *xstrdup (const char *) __attribute_malloc__ __attr_dealloc_free
 106   __returns_nonnull;
 107 void *xposix_memalign (size_t alignment, size_t n)
 108   __attribute_malloc__ __attribute_alloc_align__ ((1))
 109   __attribute_alloc_size__ ((2)) __attr_dealloc_free __returns_nonnull;
 110 char *xasprintf (const char *format, ...)
 111   __attribute__ ((format (printf, 1, 2), malloc)) __attr_dealloc_free
 112   __returns_nonnull;
 113 char *xstrdup (const char *) __attr_dealloc_free __returns_nonnull;
 114 char *xstrndup (const char *, size_t) __attr_dealloc_free __returns_nonnull;
 115 char *xsetlocale (int category, const char *locale);
 116 locale_t xnewlocale (int category_mask, const char *locale, locale_t base);
 117 char *xuselocale (locale_t newloc);
 118
 119 /* These point to the TOP of the source/build tree, not your (or
 120    support's) subdirectory.  */
 121 extern const char support_srcdir_root[];
 122 extern const char support_objdir_root[];
 123
 124 /* Corresponds to the path to the runtime linker used by the testsuite,
 125    e.g. OBJDIR_PATH/elf/ld-linux-x86-64.so.2  */
 126 extern const char support_objdir_elf_ldso[];
 127
 128 /* Corresponds to the --prefix= passed to configure.  */
 129 extern const char support_install_prefix[];
 130 /* Corresponds to the install's lib/ or lib64/ directory.  */
 131 extern const char support_libdir_prefix[];
 132 /* Corresponds to the install's bin/ directory.  */
 133 extern const char support_bindir_prefix[];
 134 /* Corresponds to the install's sbin/ directory.  */
 135 extern const char support_sbindir_prefix[];
 136 /* Corresponds to the install's system /lib or /lib64 directory.  */
 137 extern const char support_slibdir_prefix[];
 138 /* Corresponds to the install's sbin/ directory (without prefix).  */
 139 extern const char support_install_rootsbindir[];
 140 /* Corresponds to the install's compiled locale directory.  */
 141 extern const char support_complocaledir_prefix[];
 142
 143 /* Copies the file at the path FROM to TO.  If TO does not exist, it
 144    is created.  If TO is a regular file, it is truncated before
 145    copying.  The file mode is copied, but the permissions are not.  */
 146 extern void support_copy_file (const char *from, const char *to);
 147
 148 extern ssize_t support_copy_file_range (int, off64_t *, int, off64_t *,
 149                                         size_t, unsigned int);
 150
 151 /* Return true if PATH supports 64-bit time_t interfaces for file
 152    operations (such as fstatat or utimensat).  */
 153 extern bool support_path_support_time64_value (const char *path, int64_t at,
 154                                                int64_t mt);
 155 static __inline bool support_path_support_time64 (const char *path)
 156 {
 157   /* 1s and 2s after y2038 limit.  */
 158   return support_path_support_time64_value (path, 0x80000001ULL,
 159                                             0x80000002ULL);
 160 }
 161
 162 /* Return true if the setitimer and getitimer syscalls support 64-bit time_t
 163    values without resulting in overflow.  This is not true on some linux systems
 164    which have 64-bit time_t due to legacy kernel API's.  */
 165 static __inline bool support_itimer_support_time64 (void)
 166 {
 167 #ifdef __KERNEL_OLD_TIMEVAL_MATCHES_TIMEVAL64
 168   return __KERNEL_OLD_TIMEVAL_MATCHES_TIMEVAL64;
 169 #else
 170   return sizeof (__time_t) == 8;
 171 #endif
 172 }
 173
 174 /* Return true if stat supports nanoseconds resolution.  PATH is used
 175    for tests and its ctime may change.  */
 176 extern bool support_stat_nanoseconds (const char *path);
 177
 178 /* Return true if select modify the timeout to reflect the amount of time
 179    no slept.  */
 180 extern bool support_select_modifies_timeout (void);
 181
 182 /* Return true if select normalize the timeout input by taking in account
 183    tv_usec larger than 1000000.  */
 184 extern bool support_select_normalizes_timeout (void);
 185
 186 /* Create a timer that trigger after SEC seconds and NSEC nanoseconds.  If
 187    REPEAT is true the timer will repeat indefinitely.  If CALLBACK is not
 188    NULL, the function will be called when the timer expires; otherwise a
 189    dummy empty function is used instead.
 190    This is implemented with POSIX per-process timer with SIGEV_SIGNAL.  */
 191 timer_t support_create_timer (uint64_t sec, long int nsec, bool repeat,
 192                               void (*callback)(int));
 193 /* Disable the timer TIMER.  */
 194 void support_delete_timer (timer_t timer);
 195
 196 /* Wait until all threads except the current thread have exited (as
 197    far as the kernel is concerned).  */
 198 void support_wait_for_thread_exit (void);
 199
 200 struct support_stack
 201 {
 202   void *stack;
 203   size_t size;
 204   size_t guardsize;
 205 };
 206
 207 /* Allocate stack suitable to used with xclone or sigaltstack call. The stack
 208    will have a minimum size of SIZE + MINSIGSTKSZ bytes, rounded up to a whole
 209    number of pages.  There will be a large (at least 1 MiB) inaccessible guard
 210    bands on either side of it.
 211    The returned value on ALLOC_BASE and ALLOC_SIZE will be the usable stack
 212    region, excluding the GUARD_SIZE allocated area.
 213    It also terminates the process on error.  */
 214 struct support_stack support_stack_alloc (size_t size);
 215
 216 /* Deallocate the STACK.  */
 217 void support_stack_free (struct support_stack *stack);
 218
 219
 220 /* Create a range of NUM opened '/dev/null' file descriptors using FLAGS and
 221    MODE.  The function takes care of restarting the open range if a file
 222    descriptor is found within the specified range and also increases
 223    RLIMIT_NOFILE if required.
 224    The returned value is the lowest file descriptor number.  */
 225 int support_open_dev_null_range (int num, int flags, mode_t mode);
 226
 227 __END_DECLS
 228
 229 #endif /* SUPPORT_H */