check_procs: Assume we have stat()
[monitoring-plugins.git] / gl / xalloc.h
blob6122cc58b05d87da38d9f11f9dbcd849113c5b31
1 /* xalloc.h -- malloc with out-of-memory checking
3 Copyright (C) 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999,
4 2000, 2003, 2004, 2006, 2007, 2008, 2009, 2010 Free Software Foundation,
5 Inc.
7 This program is free software: you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3 of the License, or
10 (at your option) any later version.
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with this program. If not, see <http://www.gnu.org/licenses/>. */
20 #ifndef XALLOC_H_
21 # define XALLOC_H_
23 # include <stddef.h>
26 # ifdef __cplusplus
27 extern "C" {
28 # endif
31 # ifndef __attribute__
32 # if __GNUC__ < 2 || (__GNUC__ == 2 && __GNUC_MINOR__ < 8)
33 # define __attribute__(x)
34 # endif
35 # endif
37 # ifndef ATTRIBUTE_NORETURN
38 # define ATTRIBUTE_NORETURN __attribute__ ((__noreturn__))
39 # endif
41 # ifndef ATTRIBUTE_MALLOC
42 # if __GNUC__ >= 3
43 # define ATTRIBUTE_MALLOC __attribute__ ((__malloc__))
44 # else
45 # define ATTRIBUTE_MALLOC
46 # endif
47 # endif
49 /* This function is always triggered when memory is exhausted.
50 It must be defined by the application, either explicitly
51 or by using gnulib's xalloc-die module. This is the
52 function to call when one wants the program to die because of a
53 memory allocation failure. */
54 extern void xalloc_die (void) ATTRIBUTE_NORETURN;
56 void *xmalloc (size_t s) ATTRIBUTE_MALLOC;
57 void *xzalloc (size_t s) ATTRIBUTE_MALLOC;
58 void *xcalloc (size_t n, size_t s) ATTRIBUTE_MALLOC;
59 void *xrealloc (void *p, size_t s);
60 void *x2realloc (void *p, size_t *pn);
61 void *xmemdup (void const *p, size_t s) ATTRIBUTE_MALLOC;
62 char *xstrdup (char const *str) ATTRIBUTE_MALLOC;
64 /* Return 1 if an array of N objects, each of size S, cannot exist due
65 to size arithmetic overflow. S must be positive and N must be
66 nonnegative. This is a macro, not an inline function, so that it
67 works correctly even when SIZE_MAX < N.
69 By gnulib convention, SIZE_MAX represents overflow in size
70 calculations, so the conservative dividend to use here is
71 SIZE_MAX - 1, since SIZE_MAX might represent an overflowed value.
72 However, malloc (SIZE_MAX) fails on all known hosts where
73 sizeof (ptrdiff_t) <= sizeof (size_t), so do not bother to test for
74 exactly-SIZE_MAX allocations on such hosts; this avoids a test and
75 branch when S is known to be 1. */
76 # define xalloc_oversized(n, s) \
77 ((size_t) (sizeof (ptrdiff_t) <= sizeof (size_t) ? -1 : -2) / (s) < (n))
80 /* In the following macros, T must be an elementary or structure/union or
81 typedef'ed type, or a pointer to such a type. To apply one of the
82 following macros to a function pointer or array type, you need to typedef
83 it first and use the typedef name. */
85 /* Allocate an object of type T dynamically, with error checking. */
86 /* extern t *XMALLOC (typename t); */
87 # define XMALLOC(t) ((t *) xmalloc (sizeof (t)))
89 /* Allocate memory for N elements of type T, with error checking. */
90 /* extern t *XNMALLOC (size_t n, typename t); */
91 # define XNMALLOC(n, t) \
92 ((t *) (sizeof (t) == 1 ? xmalloc (n) : xnmalloc (n, sizeof (t))))
94 /* Allocate an object of type T dynamically, with error checking,
95 and zero it. */
96 /* extern t *XZALLOC (typename t); */
97 # define XZALLOC(t) ((t *) xzalloc (sizeof (t)))
99 /* Allocate memory for N elements of type T, with error checking,
100 and zero it. */
101 /* extern t *XCALLOC (size_t n, typename t); */
102 # define XCALLOC(n, t) \
103 ((t *) (sizeof (t) == 1 ? xzalloc (n) : xcalloc (n, sizeof (t))))
106 # if HAVE_INLINE
107 # define static_inline static inline
108 # else
109 void *xnmalloc (size_t n, size_t s) ATTRIBUTE_MALLOC;
110 void *xnrealloc (void *p, size_t n, size_t s);
111 void *x2nrealloc (void *p, size_t *pn, size_t s);
112 char *xcharalloc (size_t n) ATTRIBUTE_MALLOC;
113 # endif
115 # ifdef static_inline
117 /* Allocate an array of N objects, each with S bytes of memory,
118 dynamically, with error checking. S must be nonzero. */
120 static_inline void *xnmalloc (size_t n, size_t s) ATTRIBUTE_MALLOC;
121 static_inline void *
122 xnmalloc (size_t n, size_t s)
124 if (xalloc_oversized (n, s))
125 xalloc_die ();
126 return xmalloc (n * s);
129 /* Change the size of an allocated block of memory P to an array of N
130 objects each of S bytes, with error checking. S must be nonzero. */
132 static_inline void *
133 xnrealloc (void *p, size_t n, size_t s)
135 if (xalloc_oversized (n, s))
136 xalloc_die ();
137 return xrealloc (p, n * s);
140 /* If P is null, allocate a block of at least *PN such objects;
141 otherwise, reallocate P so that it contains more than *PN objects
142 each of S bytes. *PN must be nonzero unless P is null, and S must
143 be nonzero. Set *PN to the new number of objects, and return the
144 pointer to the new block. *PN is never set to zero, and the
145 returned pointer is never null.
147 Repeated reallocations are guaranteed to make progress, either by
148 allocating an initial block with a nonzero size, or by allocating a
149 larger block.
151 In the following implementation, nonzero sizes are increased by a
152 factor of approximately 1.5 so that repeated reallocations have
153 O(N) overall cost rather than O(N**2) cost, but the
154 specification for this function does not guarantee that rate.
156 Here is an example of use:
158 int *p = NULL;
159 size_t used = 0;
160 size_t allocated = 0;
162 void
163 append_int (int value)
165 if (used == allocated)
166 p = x2nrealloc (p, &allocated, sizeof *p);
167 p[used++] = value;
170 This causes x2nrealloc to allocate a block of some nonzero size the
171 first time it is called.
173 To have finer-grained control over the initial size, set *PN to a
174 nonzero value before calling this function with P == NULL. For
175 example:
177 int *p = NULL;
178 size_t used = 0;
179 size_t allocated = 0;
180 size_t allocated1 = 1000;
182 void
183 append_int (int value)
185 if (used == allocated)
187 p = x2nrealloc (p, &allocated1, sizeof *p);
188 allocated = allocated1;
190 p[used++] = value;
195 static_inline void *
196 x2nrealloc (void *p, size_t *pn, size_t s)
198 size_t n = *pn;
200 if (! p)
202 if (! n)
204 /* The approximate size to use for initial small allocation
205 requests, when the invoking code specifies an old size of
206 zero. 64 bytes is the largest "small" request for the
207 GNU C library malloc. */
208 enum { DEFAULT_MXFAST = 64 };
210 n = DEFAULT_MXFAST / s;
211 n += !n;
214 else
216 /* Set N = ceil (1.5 * N) so that progress is made if N == 1.
217 Check for overflow, so that N * S stays in size_t range.
218 The check is slightly conservative, but an exact check isn't
219 worth the trouble. */
220 if ((size_t) -1 / 3 * 2 / s <= n)
221 xalloc_die ();
222 n += (n + 1) / 2;
225 *pn = n;
226 return xrealloc (p, n * s);
229 /* Return a pointer to a new buffer of N bytes. This is like xmalloc,
230 except it returns char *. */
232 static_inline char *xcharalloc (size_t n) ATTRIBUTE_MALLOC;
233 static_inline char *
234 xcharalloc (size_t n)
236 return XNMALLOC (n, char);
239 # endif
241 # ifdef __cplusplus
244 /* C++ does not allow conversions from void * to other pointer types
245 without a cast. Use templates to work around the problem when
246 possible. */
248 template <typename T> inline T *
249 xrealloc (T *p, size_t s)
251 return (T *) xrealloc ((void *) p, s);
254 template <typename T> inline T *
255 xnrealloc (T *p, size_t n, size_t s)
257 return (T *) xnrealloc ((void *) p, n, s);
260 template <typename T> inline T *
261 x2realloc (T *p, size_t *pn)
263 return (T *) x2realloc ((void *) p, pn);
266 template <typename T> inline T *
267 x2nrealloc (T *p, size_t *pn, size_t s)
269 return (T *) x2nrealloc ((void *) p, pn, s);
272 template <typename T> inline T *
273 xmemdup (T const *p, size_t s)
275 return (T *) xmemdup ((void const *) p, s);
278 # endif
281 #endif /* !XALLOC_H_ */