/* $NetBSD: memalloc.c,v 1.42 2026/04/18 14:35:16 kre Exp $ */ /*- * Copyright (c) 1991, 1993 * The Regents of the University of California. All rights reserved. * * This code is derived from software contributed to Berkeley by * Kenneth Almquist. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ #include <sys/cdefs.h> #ifndef lint #if 0 static char sccsid[] = "@(#)memalloc.c 8.3 (Berkeley) 5/4/95"; #else __RCSID("$NetBSD: memalloc.c,v 1.42 2026/04/18 14:35:16 kre Exp $"); #endif #endif /* not lint */ #include <limits.h> #include <stdarg.h> #include <stdlib.h> #include <unistd.h> #include "shell.h" #include "output.h" #include "memalloc.h" #include "error.h" #include "machdep.h" #include "mystring.h" /* * Like malloc, but returns an error when out of space. */ pointer ckmalloc(size_t nbytes) { pointer p; p = malloc(nbytes); if (p == NULL) error("Out of space"); return p; } /* * Same for realloc. */ pointer ckrealloc(pointer p, int nbytes) { p = realloc(p, nbytes); if (p == NULL) error("Out of space"); return p; } /* * Make a copy of a string in safe storage. */ char * savestr(const char *s) { char *p; p = ckmalloc(strlen(s) + 1); scopy(s, p); return p; } /* * Parse trees for commands are allocated in lifo order, so we use a stack * to make this more efficient, and also to avoid all sorts of exception * handling code to handle interrupts in the middle of a parse. * * The size 504 was chosen because the Ultrix malloc handles that size * well. */ #define MINSIZE 504 /* minimum size of a block */ struct stack_block { struct stack_block *prev; char space[MINSIZE]; }; struct stack_block stackbase; struct stack_block *stackp = &stackbase; struct stackmark *markp; char *stacknxt = stackbase.space; int stacknleft = MINSIZE; int sstrnleft; pointer stalloc(int nbytes) { char *p; nbytes = SHELL_ALIGN(nbytes); if (nbytes > stacknleft) { int blocksize; struct stack_block *sp; blocksize = nbytes; if (blocksize < MINSIZE) blocksize = MINSIZE; INTOFF; sp = ckmalloc(sizeof(struct stack_block) - MINSIZE + blocksize); sp->prev = stackp; stacknxt = sp->space; stacknleft = blocksize; stackp = sp; INTON; } INTOFF; p = stacknxt; stacknxt += nbytes; stacknleft -= nbytes; INTON; return p; } void stunalloc(pointer p) { if (p == NULL) { /*DEBUG */ write(2, "stunalloc\n", 10); abort(); } stacknleft += stacknxt - (char *)p; stacknxt = p; } /* save the current status of the sh stack */ void setstackmark(struct stackmark *mark) { mark->stackp = stackp; mark->stacknxt = stacknxt; mark->stacknleft = stacknleft; mark->sstrnleft = sstrnleft; mark->marknext = markp; markp = mark; } /* reset the stack mark, and remove it from the list of marks */ void popstackmark(struct stackmark *mark) { INTOFF; markp = mark->marknext; /* delete mark from the list */ rststackmark(mark); /* and reset stack */ INTON; } /* reset the shell stack to its state recorded in the stack mark */ void rststackmark(struct stackmark *mark) { struct stack_block *sp; INTOFF; while (stackp != mark->stackp) { /* delete any recently allocated mem blocks */ sp = stackp; stackp = sp->prev; ckfree(sp); } stacknxt = mark->stacknxt; stacknleft = mark->stacknleft; sstrnleft = mark->sstrnleft; INTON; } /* * When the parser reads in a string, it wants to stick the string on the * stack and only adjust the stack pointer when it knows how big the * string is. Stackblock (defined in stack.h) returns a pointer to a block * of space on top of the stack and stackblocklen returns the length of * this block. Growstackblock will grow this space by at least one byte, * possibly moving it (like realloc). Grabstackblock actually allocates the * part of the block that has been used. */ void growstackblock(void) { int newlen = SHELL_ALIGN(stacknleft * 2 + 100); INTOFF; if (stacknxt == stackp->space && stackp != &stackbase) { struct stack_block *oldstackp; struct stackmark *xmark; struct stack_block *sp; oldstackp = stackp; sp = stackp; stackp = sp->prev; sp = ckrealloc((pointer)sp, sizeof(struct stack_block) - MINSIZE + newlen); sp->prev = stackp; stackp = sp; stacknxt = sp->space; sstrnleft += newlen - stacknleft; stacknleft = newlen; /* * Stack marks pointing to the start of the old block * must be relocated to point to the new block */ xmark = markp; while (xmark != NULL && xmark->stackp == oldstackp) { xmark->stackp = stackp; xmark->stacknxt = stacknxt; xmark->sstrnleft += stacknleft - xmark->stacknleft; xmark->stacknleft = stacknleft; xmark = xmark->marknext; } } else { char *oldspace = stacknxt; int oldlen = stacknleft; char *p = stalloc(newlen); (void)memcpy(p, oldspace, oldlen); stacknxt = p; /* free the space */ stacknleft += newlen; /* we just allocated */ } INTON; } void grabstackblock(int len) { len = SHELL_ALIGN(len); INTOFF; stacknxt += len; stacknleft -= len; INTON; } /* * The following routines are somewhat easier to use than the above. * The macro STARTSTACKSTR(ptr) initializes things. "ptr" must be the * name of a "char *" variable. Then the user uses the macro STPUTC to * add characters to the string. In effect, STPUTC(c, ptr) is the same * as *ptr++ = c except that the stack is grown as necessary. Note that * the value of ptr is not exoected to increase linearly, its value * after a call to STPUTC() is not comparable to any value it had before. * * When the user is done, she can just leave the string there and refer to * it using stackblock(). In that case, the string will be overwritten by * the next call to stalloc() or STARTSTACKSTR(). Or she can allocate * the space for it using grabstackstr(). If it is necessary to allow * someone else to use the stack temporarily and then continue to grow * the string, the user should use grabstackstr() to allocate the space, * and then call ungrabstackstr(p) to return to the previous mode of operation. * * USTPUTC is like STPUTC except that it doesn't check for overflow. * CHECKSTACKSPACE can be called before USTPUTC to ensure that there * is space for (at least) some known number of calls to USTPUTC() * CHECKSTACKSPACE may make arbitrary changes to the ptr, USTPUTC does not. * * STUNPUTC() is the inverse of STPUTC() (and USTPUTC()) and undoes * the most recent (not previously undone) call of either of those. * The user must ensure that no more than what has been added to the * current string is removed. * * Aside from when adjusted by the macros/functions here, the "ptr" * variable MUST not be altered (it can be used to examine data). * The ptr var always refers to one past the most recently added byte, * *ptr is is always undefined as is ptr[1] (etc), but ptr[-1] can * be used after data has been added (STTOPC() is a cleaner way). */ char * growstackstr(void) { int len = stackblocksize(); growstackblock(); sstrnleft = stackblocksize() - len - 1; return stackblock() + len; } /* * Called from CHECKSTRSPACE(). (nowhere else) * Make sure there is space for "required" bytes */ char * makestrspace(int required) { int len = stackblocksize() - sstrnleft; do { growstackblock(); sstrnleft = stackblocksize() - len; } while (sstrnleft < required); return stackblock() + len; } /* * Note that this only works to release stack space for reuse * if nothing else has allocated space on the stack since the grabstackstr() * * "s" is the start of the area to be released, and "p" represents the end * of the string we have stored beyond there and are now releasing. * (ie: "p" should be the same as in the call to grabstackstr()). * * stunalloc(s) and ungrabstackstr(s, p) are almost interchangeable after * a grabstackstr(), however the latter also returns string space so we * can just continue with STPUTC() etc without needing a new STARTSTACKSTR(s) */ void ungrabstackstr(char *s, char *p) { #ifdef DEBUG if (s < stacknxt || stacknxt + stacknleft < s) abort(); #endif stacknleft += stacknxt - s; stacknxt = s; sstrnleft = stacknleft - (p - s); } /* * Save the concat of a sequence of strings in stack space * * The first arg (if not NULL) is a pointer to where the final string * length will be returned. * * Remaining args are pointers to strings - sufficient space to hold * the concat of the strings is allocated on the stack, the strings * are copied into that space, and a pointer to its start is returned. * The arg list is terminated with STSTRC_END. * * Use stunalloc(string) (in proper sequence) to release the string */ char * ststrcat(size_t *lp, ...) { va_list ap; const char *arg; size_t len, tlen = 0, alen[8]; char *str, *nxt; unsigned int n; n = 0; va_start(ap, lp); arg = va_arg(ap, const char *); while (arg != STSTRC_END) { len = strlen(arg); if (n < sizeof(alen)/sizeof(alen[0])) alen[n++] = len; tlen += len; arg = va_arg(ap, const char *); } va_end(ap); if (lp != NULL) *lp = tlen; if (tlen >= INT_MAX) error("ststrcat() over length botch"); str = (char *)stalloc((int)tlen + 1); /* 1 for \0 */ str[tlen] = '\0'; /* in case of no args */ n = 0; nxt = str; va_start(ap, lp); arg = va_arg(ap, const char *); while (arg != STSTRC_END) { if (n < sizeof(alen)/sizeof(alen[0])) len = alen[n++]; else len = strlen(arg); scopy(arg, nxt); nxt += len; arg = va_arg(ap, const char *); } va_end(ap); return str; }
