/* dynamic memory allocation for GNU. Copyright (C) 1985, 1987 Free Software Foundation, Inc. NO WARRANTY BECAUSE THIS PROGRAM IS LICENSED FREE OF CHARGE, WE PROVIDE ABSOLUTELY NO WARRANTY, TO THE EXTENT PERMITTED BY APPLICABLE STATE LAW. EXCEPT WHEN OTHERWISE STATED IN WRITING, FREE SOFTWARE FOUNDATION, INC, RICHARD M. STALLMAN AND/OR OTHER PARTIES PROVIDE THIS PROGRAM "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU. SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING, REPAIR OR CORRECTION. IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW WILL RICHARD M. STALLMAN, THE FREE SOFTWARE FOUNDATION, INC., AND/OR ANY OTHER PARTY WHO MAY MODIFY AND REDISTRIBUTE THIS PROGRAM AS PERMITTED BELOW, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY LOST PROFITS, LOST MONIES, OR OTHER SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OR INABILITY TO USE (INCLUDING BUT NOT LIMITED TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS) THIS PROGRAM, EVEN IF YOU HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES, OR FOR ANY CLAIM BY ANY OTHER PARTY. GENERAL PUBLIC LICENSE TO COPY 1. You may copy and distribute verbatim copies of this source file as you receive it, in any medium, provided that you conspicuously and appropriately publish on each copy a valid copyright notice "Copyright (C) 1985 Free Software Foundation, Inc."; and include following the copyright notice a verbatim copy of the above disclaimer of warranty and of this License. You may charge a distribution fee for the physical act of transferring a copy. 2. You may modify your copy or copies of this source file or any portion of it, and copy and distribute such modifications under the terms of Paragraph 1 above, provided that you also do the following: a) cause the modified files to carry prominent notices stating that you changed the files and the date of any change; and b) cause the whole of any work that you distribute or publish, that in whole or in part contains or is a derivative of this program or any part thereof, to be licensed at no charge to all third parties on terms identical to those contained in this License Agreement (except that you may choose to grant more extensive warranty protection to some or all third parties, at your option). c) You may charge a distribution fee for the physical act of transferring a copy, and you may at your option offer warranty protection in exchange for a fee. Mere aggregation of another unrelated program with this program (or its derivative) on a volume of a storage or distribution medium does not bring the other program under the scope of these terms. 3. You may copy and distribute this program (or a portion or derivative of it, under Paragraph 2) in object code or executable form under the terms of Paragraphs 1 and 2 above provided that you also do one of the following: a) accompany it with the complete corresponding machine-readable source code, which must be distributed under the terms of Paragraphs 1 and 2 above; or, b) accompany it with a written offer, valid for at least three years, to give any third party free (except for a nominal shipping charge) a complete machine-readable copy of the corresponding source code, to be distributed under the terms of Paragraphs 1 and 2 above; or, c) accompany it with the information you received as to where the corresponding source code may be obtained. (This alternative is allowed only for noncommercial distribution and only if you received the program in object code or executable form alone.) For an executable file, complete source code means all the source code for all modules it contains; but, as a special exception, it need not include source code for modules which are standard libraries that accompany the operating system on which the executable file runs. 4. You may not copy, sublicense, distribute or transfer this program except as expressly provided under this License Agreement. Any attempt otherwise to copy, sublicense, distribute or transfer this program is void and your rights to use the program under this License agreement shall be automatically terminated. However, parties who have received computer software programs from you with this License Agreement will not have their licenses terminated so long as such parties remain in full compliance. 5. If you wish to incorporate parts of this program into other free programs whose distribution conditions are different, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.. We have not yet worked out a simple rule that can be stated here, but we will often permit this. We will be guided by the two goals of preserving the free status of all derivatives of our free software and of promoting the sharing and reuse of software. In other words, you are welcome to use, share and improve this program. You are forbidden to forbid anyone else to use, share and improve what you give them. Help stamp out software-hoarding! */ /* Synched up with: Not synched with FSF. */ /* * @(#)nmalloc.c 1 (Caltech) 2/21/82 * * U of M Modified: 20 Jun 1983 ACT: strange hacks for Emacs * * Nov 1983, Mike@BRL, Added support for 4.1C/4.2 BSD. * * This is a very fast storage allocator. It allocates blocks of a small * number of different sizes, and keeps free lists of each size. Blocks * that don't exactly fit are passed up to the next larger size. In this * implementation, the available sizes are (2^n)-4 (or -16) bytes long. * This is designed for use in a program that uses vast quantities of * memory, but bombs when it runs out. To make it a little better, it * warns the user when he starts to get near the end. * * June 84, ACT: modified rcheck code to check the range given to malloc, * rather than the range determined by the 2-power used. * * Jan 85, RMS: calls malloc_warning to issue warning on nearly full. * No longer Emacs-specific; can serve as all-purpose malloc for GNU. * You should call malloc_init to reinitialize after loading dumped Emacs. * Call malloc_stats to get info on memory stats if MSTATS turned on. * realloc knows how to return same block given, just changing its size, * if the power of 2 is correct. */ /* * nextf[i] is the pointer to the next free block of size 2^(i+3). The * smallest allocatable block is 8 bytes. The overhead information will * go in the first int of the block, and the returned pointer will point * to the second. * #ifdef MSTATS * nmalloc[i] is the difference between the number of mallocs and frees * for a given block size. #endif MSTATS */ #ifdef emacs /* config.h specifies which kind of system this is. */ #include #else /* Determine which kind of system this is. */ #include #ifndef SIGTSTP #ifndef USG #define USG #endif #else /* SIGTSTP */ #ifdef SIGIO #define BSD4_2 #endif /* SIGIO */ #endif /* SIGTSTP */ #if defined(hpux) #define USG #endif #endif /* not emacs */ #include /* Define getpagesize () if the system does not. */ #include "getpagesize.h" #ifdef HAVE_ULIMIT_H #include #endif #ifndef BSD4_2 #ifndef USG #include /* warn the user when near the end */ #endif /* not USG */ #else /* if BSD4_2 */ #include #include #endif /* BSD4_2 */ #ifdef __STDC__ #ifndef HPUX /* not sure where this for NetBSD should really go and it probably applies to other systems */ #if !defined(__NetBSD__) && !defined(__bsdi__) && !defined(__OpenBSD__) extern void *sbrk (ptrdiff_t); #else extern char *sbrk (); #endif /* __NetBSD__ or __OpenBSD__ */ #endif /* HPUX */ #else extern void *sbrk (); #endif /* __STDC__ */ extern char *start_of_data (void); #ifdef BSD #define start_of_data() &etext #endif #ifndef emacs #define start_of_data() &etext #endif #define ISALLOC ((char) 0xf7) /* magic byte that implies allocation */ #define ISFREE ((char) 0x54) /* magic byte that implies free block */ /* this is for error checking only */ #define ISMEMALIGN ((char) 0xd6) /* Stored before the value returned by memalign, with the rest of the word being the distance to the true beginning of the block. */ extern char etext; /* These two are for user programs to look at, when they are interested. */ unsigned int malloc_sbrk_used; /* amount of data space used now */ unsigned int malloc_sbrk_unused; /* amount more we can have */ /* start of data space; can be changed by calling init_malloc */ static char *data_space_start; #ifdef MSTATS static int nmalloc[30]; static int nmal, nfre; #endif /* MSTATS */ /* If range checking is not turned on, all we have is a flag indicating whether memory is allocated, an index in nextf[], and a size field; to realloc() memory we copy either size bytes or 1<<(index+3) bytes depending on whether the former can hold the exact size (given the value of 'index'). If range checking is on, we always need to know how much space is allocated, so the 'size' field is never used. */ struct mhead { char mh_alloc; /* ISALLOC or ISFREE */ char mh_index; /* index in nextf[] */ /* Remainder are valid only when block is allocated */ unsigned short mh_size; /* size, if < 0x10000 */ #ifdef rcheck unsigned mh_nbytes; /* number of bytes allocated */ int mh_magic4; /* should be == MAGIC4 */ #endif /* rcheck */ }; /* Access free-list pointer of a block. It is stored at block + 4. This is not a field in the mhead structure because we want sizeof (struct mhead) to describe the overhead for when the block is in use, and we do not want the free-list pointer to count in that. */ #define CHAIN(a) \ (*(struct mhead **) (sizeof (char *) + (char *) (a))) #ifdef rcheck /* To implement range checking, we write magic values in at the beginning and end of each allocated block, and make sure they are undisturbed whenever a free or a realloc occurs. */ /* Written in each of the 4 bytes following the block's real space */ #define MAGIC1 0x55 /* Written in the 4 bytes before the block's real space */ #define MAGIC4 0x55555555 #define ASSERT(p) if (!(p)) botch("p"); else #define EXTRA 4 /* 4 bytes extra for MAGIC1s */ #else #define ASSERT(p) #define EXTRA 0 #endif /* rcheck */ /* nextf[i] is free list of blocks of size 2**(i + 3) */ static struct mhead *nextf[30]; /* busy[i] is nonzero while allocation of block size i is in progress. */ static char busy[30]; /* Number of bytes of writable memory we can expect to be able to get */ extern unsigned long lim_data; /* Level number of warnings already issued. 0 -- no warnings issued. 1 -- 75% warning already issued. 2 -- 85% warning already issued. */ static int warnlevel; /* Function to call to issue a warning; 0 means don't issue them. */ static void (*warnfunction) (); /* nonzero once initial bunch of free blocks made */ static int gotpool; char *_malloc_base; static void getpool (void); /* Cause reinitialization based on job parameters; also declare where the end of pure storage is. */ void malloc_init (start, warnfun) char *start; void (*warnfun) (); { if (start) data_space_start = start; lim_data = 0; warnlevel = 0; warnfunction = warnfun; } /* Return the maximum size to which MEM can be realloc'd without actually requiring copying. */ int malloc_usable_size (mem) char *mem; { int blocksize = 8 << (((struct mhead *) mem) - 1) -> mh_index; return blocksize - sizeof (struct mhead) - EXTRA; } static void get_lim_data (); static void morecore (nu) /* ask system for more memory */ int nu; /* size index to get more of */ { char *cp; int nblks; unsigned long siz; int oldmask; #ifdef BSD #ifndef BSD4_1 /* ?? There was a suggestion not to block SIGILL, somehow for GDB's sake. */ oldmask = sigsetmask (-1); #endif #endif if (!data_space_start) { data_space_start = start_of_data (); } if (lim_data == 0) get_lim_data (); /* On initial startup, get two blocks of each size up to 1k bytes */ if (!gotpool) { getpool (); getpool (); gotpool = 1; } /* Find current end of memory and issue warning if getting near max */ cp = sbrk (0); siz = cp - data_space_start; if (warnfunction) switch (warnlevel) { case 0: if (siz > (lim_data / 4) * 3) { warnlevel++; (*warnfunction) ("Warning: past 75% of memory limit"); } break; case 1: if (siz > (lim_data / 20) * 17) { warnlevel++; (*warnfunction) ("Warning: past 85% of memory limit"); } break; case 2: if (siz > (lim_data / 20) * 19) { warnlevel++; (*warnfunction) ("Warning: past 95% of memory limit"); } break; } if ((int) cp & 0x3ff) /* land on 1K boundaries */ sbrk (1024 - ((int) cp & 0x3ff)); /* Take at least 2k, and figure out how many blocks of the desired size we're about to get */ nblks = 1; if ((siz = nu) < 8) nblks = 1 << ((siz = 8) - nu); if ((cp = sbrk (1 << (siz + 3))) == (char *) -1) { #ifdef BSD #ifndef BSD4_1 sigsetmask (oldmask); #endif #endif return; /* no more room! */ } malloc_sbrk_used = siz; malloc_sbrk_unused = lim_data - siz; if ((int) cp & 7) { /* shouldn't happen, but just in case */ cp = (char *) (((int) cp + 8) & ~7); nblks--; } /* save new header and link the nblks blocks together */ nextf[nu] = (struct mhead *) cp; siz = 1 << (nu + 3); while (1) { ((struct mhead *) cp) -> mh_alloc = ISFREE; ((struct mhead *) cp) -> mh_index = nu; if (--nblks <= 0) break; CHAIN ((struct mhead *) cp) = (struct mhead *) (cp + siz); cp += siz; } CHAIN ((struct mhead *) cp) = 0; #ifdef BSD #ifndef BSD4_1 sigsetmask (oldmask); #endif #endif } static void getpool (void) { int nu; char *cp = sbrk (0); if ((int) cp & 0x3ff) /* land on 1K boundaries */ sbrk (1024 - ((int) cp & 0x3ff)); /* Record address of start of space allocated by malloc. */ if (_malloc_base == 0) _malloc_base = cp; /* Get 2k of storage */ cp = sbrk (04000); if (cp == (char *) -1) return; /* Divide it into an initial 8-word block plus one block of size 2**nu for nu = 3 ... 10. */ CHAIN (cp) = nextf[0]; nextf[0] = (struct mhead *) cp; ((struct mhead *) cp) -> mh_alloc = ISFREE; ((struct mhead *) cp) -> mh_index = 0; cp += 8; for (nu = 0; nu < 7; nu++) { CHAIN (cp) = nextf[nu]; nextf[nu] = (struct mhead *) cp; ((struct mhead *) cp) -> mh_alloc = ISFREE; ((struct mhead *) cp) -> mh_index = nu; cp += 8 << nu; } } char * malloc (n) /* get a block */ unsigned n; { struct mhead *p; unsigned int nbytes; int nunits = 0; /* Figure out how many bytes are required, rounding up to the nearest multiple of 8, then figure out which nestf[] area to use. Both the beginning of the header and the beginning of the block should be on an eight byte boundary. */ nbytes = (n + ((sizeof *p + 7) & ~7) + EXTRA + 7) & ~7; { unsigned int shiftr = (nbytes - 1) >> 2; while (shiftr >>= 1) nunits++; } /* In case this is reentrant use of malloc from signal handler, pick a block size that no other malloc level is currently trying to allocate. That's the easiest harmless way not to interfere with the other level of execution. */ while (busy[nunits]) nunits++; busy[nunits] = 1; /* If there are no blocks of the appropriate size, go get some */ /* COULD SPLIT UP A LARGER BLOCK HERE ... ACT */ if (nextf[nunits] == 0) morecore (nunits); /* Get one block off the list, and set the new list head */ if ((p = nextf[nunits]) == 0) { busy[nunits] = 0; return 0; } nextf[nunits] = CHAIN (p); busy[nunits] = 0; /* Check for free block clobbered */ /* If not for this check, we would gobble a clobbered free chain ptr */ /* and bomb out on the NEXT allocate of this size block */ if (p -> mh_alloc != ISFREE || p -> mh_index != nunits) #ifdef rcheck botch ("block on free list clobbered"); #else /* not rcheck */ ABORT (); #endif /* not rcheck */ /* Fill in the info, and if range checking, set up the magic numbers */ p -> mh_alloc = ISALLOC; #ifdef rcheck p -> mh_nbytes = n; p -> mh_magic4 = MAGIC4; { /* Get the location n after the beginning of the user's space. */ char *m = (char *) p + ((sizeof *p + 7) & ~7) + n; *m++ = MAGIC1, *m++ = MAGIC1, *m++ = MAGIC1, *m = MAGIC1; } #else /* not rcheck */ p -> mh_size = n; #endif /* not rcheck */ #ifdef MSTATS nmalloc[nunits]++; nmal++; #endif /* MSTATS */ return (char *) p + ((sizeof *p + 7) & ~7); } void free (mem) char *mem; { struct mhead *p; { char *ap = mem; if (ap == 0) return; p = (struct mhead *) (ap - ((sizeof *p + 7) & ~7)); if (p -> mh_alloc == ISMEMALIGN) { ap -= p->mh_size; p = (struct mhead *) (ap - ((sizeof *p + 7) & ~7)); } #ifndef rcheck if (p -> mh_alloc != ISALLOC) ABORT (); #else /* rcheck */ if (p -> mh_alloc != ISALLOC) { if (p -> mh_alloc == ISFREE) botch ("free: Called with already freed block argument\n"); else botch ("free: Called with bad argument\n"); } ASSERT (p -> mh_magic4 == MAGIC4); ap += p -> mh_nbytes; ASSERT (*ap++ == MAGIC1); ASSERT (*ap++ == MAGIC1); ASSERT (*ap++ == MAGIC1); ASSERT (*ap == MAGIC1); #endif /* rcheck */ } { int nunits = p -> mh_index; ASSERT (nunits <= 29); p -> mh_alloc = ISFREE; /* Protect against signal handlers calling malloc. */ busy[nunits] = 1; /* Put this block on the free list. */ CHAIN (p) = nextf[nunits]; nextf[nunits] = p; busy[nunits] = 0; #ifdef MSTATS nmalloc[nunits]--; nfre++; #endif /* MSTATS */ } } char * realloc (mem, n) char *mem; unsigned n; { struct mhead *p; unsigned int tocopy; unsigned int nbytes; int nunits; if (mem == 0) return malloc (n); p = (struct mhead *) (mem - ((sizeof *p + 7) & ~7)); nunits = p -> mh_index; ASSERT (p -> mh_alloc == ISALLOC); #ifdef rcheck ASSERT (p -> mh_magic4 == MAGIC4); { char *m = mem + (tocopy = p -> mh_nbytes); ASSERT (*m++ == MAGIC1); ASSERT (*m++ == MAGIC1); ASSERT (*m++ == MAGIC1); ASSERT (*m == MAGIC1); } #else /* not rcheck */ if (p -> mh_index >= 13) tocopy = (1 << (p -> mh_index + 3)) - ((sizeof *p + 7) & ~7); else tocopy = p -> mh_size; #endif /* not rcheck */ /* See if desired size rounds to same power of 2 as actual size. */ nbytes = (n + ((sizeof *p + 7) & ~7) + EXTRA + 7) & ~7; /* If ok, use the same block, just marking its size as changed. */ if (nbytes > (4 << nunits) && nbytes <= (8 << nunits)) { #ifdef rcheck char *m = mem + tocopy; *m++ = 0; *m++ = 0; *m++ = 0; *m++ = 0; p-> mh_nbytes = n; m = mem + n; *m++ = MAGIC1; *m++ = MAGIC1; *m++ = MAGIC1; *m++ = MAGIC1; #else /* not rcheck */ p -> mh_size = n; #endif /* not rcheck */ return mem; } if (n < tocopy) tocopy = n; { char *new; if ((new = malloc (n)) == 0) return 0; memcpy (new, mem, tocopy); free (mem); return new; } } char * memalign (alignment, size) unsigned alignment, size; { char *ptr = malloc (size + alignment); char *aligned; struct mhead *p; if (ptr == 0) return 0; /* If entire block has the desired alignment, just accept it. */ if (((int) ptr & (alignment - 1)) == 0) return ptr; /* Otherwise, get address of byte in the block that has that alignment. */ aligned = (char *) (((int) ptr + alignment - 1) & -alignment); /* Store a suitable indication of how to free the block, so that free can find the true beginning of it. */ p = (struct mhead *) aligned - 1; p -> mh_size = aligned - ptr; p -> mh_alloc = ISMEMALIGN; return aligned; } #ifndef __hpux /* This runs into trouble with getpagesize on HPUX. Patching out seems cleaner than the ugly fix needed. */ char * valloc (size) unsigned size; { return memalign (getpagesize (), size); } #endif /* not __hpux */ #ifdef MSTATS /* Return statistics describing allocation of blocks of size 2**n. */ struct mstats_value { int blocksize; int nfree; int nused; }; struct mstats_value malloc_stats (size) int size; { struct mstats_value v; int i; struct mhead *p; v.nfree = 0; if (size < 0 || size >= 30) { v.blocksize = 0; v.nused = 0; return v; } v.blocksize = 1 << (size + 3); v.nused = nmalloc[size]; for (p = nextf[size]; p; p = CHAIN (p)) v.nfree++; return v; } int malloc_mem_used (void) { int i; int size_used; size_used = 0; for (i = 0; i < 30; i++) { int allocation_size = 1 << (i + 3); struct mhead *p; size_used += nmalloc[i] * allocation_size; } return size_used; } int malloc_mem_free (void) { int i; int size_unused; size_unused = 0; for (i = 0; i < 30; i++) { int allocation_size = 1 << (i + 3); struct mhead *p; for (p = nextf[i]; p ; p = CHAIN (p)) size_unused += allocation_size; } return size_unused; } #endif /* MSTATS */ /* * This function returns the total number of bytes that the process * will be allowed to allocate via the sbrk(2) system call. On * BSD systems this is the total space allocatable to stack and * data. On USG systems this is the data space only. */ #ifdef USG static void get_lim_data (void) { #ifdef ULIMIT_BREAK_VALUE lim_data = ULIMIT_BREAK_VALUE; #else lim_data = ulimit (3, 0); #endif lim_data -= (long) data_space_start; } #else /* not USG */ #ifndef BSD4_2 static void get_lim_data (void) { lim_data = vlimit (LIM_DATA, -1); } #else /* BSD4_2 */ static void get_lim_data (void) { struct rlimit XXrlimit; getrlimit (RLIMIT_DATA, &XXrlimit); #ifdef RLIM_INFINITY lim_data = XXrlimit.rlim_cur & RLIM_INFINITY; /* soft limit */ #else lim_data = XXrlimit.rlim_cur; /* soft limit */ #endif } #endif /* BSD4_2 */ #endif /* not USG */