Revision 1feb40067cf04ae48d65f728d62ca255c9449178 authored by Mike Marciniszyn on 12 May 2017, 16:02:00 UTC, committed by Doug Ledford on 01 June 2017, 21:04:33 UTC
The handling of IB_RDMA_WRITE_ONLY_WITH_IMMEDIATE will leak a memory
reference when a buffer cannot be allocated for returning the immediate
data.

The issue is that the rkey validation has already occurred and the RNR
nak fails to release the reference that was fruitlessly gotten.  The
the peer will send the identical single packet request when its RNR
timer pops.

The fix is to release the held reference prior to the rnr nak exit.
This is the only sequence the requires both rkey validation and the
buffer allocation on the same packet.

Cc: Stable <stable@vger.kernel.org> # 4.7+
Tested-by: Tadeusz Struk <tadeusz.struk@intel.com>
Reviewed-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
1 parent b3e6b4b
Raw File
expr.c
/*
 * Copyright (C) 2002 Roman Zippel <zippel@linux-m68k.org>
 * Released under the terms of the GNU GPL v2.0.
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "lkc.h"

#define DEBUG_EXPR	0

static int expr_eq(struct expr *e1, struct expr *e2);
static struct expr *expr_eliminate_yn(struct expr *e);

struct expr *expr_alloc_symbol(struct symbol *sym)
{
	struct expr *e = xcalloc(1, sizeof(*e));
	e->type = E_SYMBOL;
	e->left.sym = sym;
	return e;
}

struct expr *expr_alloc_one(enum expr_type type, struct expr *ce)
{
	struct expr *e = xcalloc(1, sizeof(*e));
	e->type = type;
	e->left.expr = ce;
	return e;
}

struct expr *expr_alloc_two(enum expr_type type, struct expr *e1, struct expr *e2)
{
	struct expr *e = xcalloc(1, sizeof(*e));
	e->type = type;
	e->left.expr = e1;
	e->right.expr = e2;
	return e;
}

struct expr *expr_alloc_comp(enum expr_type type, struct symbol *s1, struct symbol *s2)
{
	struct expr *e = xcalloc(1, sizeof(*e));
	e->type = type;
	e->left.sym = s1;
	e->right.sym = s2;
	return e;
}

struct expr *expr_alloc_and(struct expr *e1, struct expr *e2)
{
	if (!e1)
		return e2;
	return e2 ? expr_alloc_two(E_AND, e1, e2) : e1;
}

struct expr *expr_alloc_or(struct expr *e1, struct expr *e2)
{
	if (!e1)
		return e2;
	return e2 ? expr_alloc_two(E_OR, e1, e2) : e1;
}

struct expr *expr_copy(const struct expr *org)
{
	struct expr *e;

	if (!org)
		return NULL;

	e = xmalloc(sizeof(*org));
	memcpy(e, org, sizeof(*org));
	switch (org->type) {
	case E_SYMBOL:
		e->left = org->left;
		break;
	case E_NOT:
		e->left.expr = expr_copy(org->left.expr);
		break;
	case E_EQUAL:
	case E_GEQ:
	case E_GTH:
	case E_LEQ:
	case E_LTH:
	case E_UNEQUAL:
		e->left.sym = org->left.sym;
		e->right.sym = org->right.sym;
		break;
	case E_AND:
	case E_OR:
	case E_LIST:
		e->left.expr = expr_copy(org->left.expr);
		e->right.expr = expr_copy(org->right.expr);
		break;
	default:
		printf("can't copy type %d\n", e->type);
		free(e);
		e = NULL;
		break;
	}

	return e;
}

void expr_free(struct expr *e)
{
	if (!e)
		return;

	switch (e->type) {
	case E_SYMBOL:
		break;
	case E_NOT:
		expr_free(e->left.expr);
		return;
	case E_EQUAL:
	case E_GEQ:
	case E_GTH:
	case E_LEQ:
	case E_LTH:
	case E_UNEQUAL:
		break;
	case E_OR:
	case E_AND:
		expr_free(e->left.expr);
		expr_free(e->right.expr);
		break;
	default:
		printf("how to free type %d?\n", e->type);
		break;
	}
	free(e);
}

static int trans_count;

#define e1 (*ep1)
#define e2 (*ep2)

static void __expr_eliminate_eq(enum expr_type type, struct expr **ep1, struct expr **ep2)
{
	if (e1->type == type) {
		__expr_eliminate_eq(type, &e1->left.expr, &e2);
		__expr_eliminate_eq(type, &e1->right.expr, &e2);
		return;
	}
	if (e2->type == type) {
		__expr_eliminate_eq(type, &e1, &e2->left.expr);
		__expr_eliminate_eq(type, &e1, &e2->right.expr);
		return;
	}
	if (e1->type == E_SYMBOL && e2->type == E_SYMBOL &&
	    e1->left.sym == e2->left.sym &&
	    (e1->left.sym == &symbol_yes || e1->left.sym == &symbol_no))
		return;
	if (!expr_eq(e1, e2))
		return;
	trans_count++;
	expr_free(e1); expr_free(e2);
	switch (type) {
	case E_OR:
		e1 = expr_alloc_symbol(&symbol_no);
		e2 = expr_alloc_symbol(&symbol_no);
		break;
	case E_AND:
		e1 = expr_alloc_symbol(&symbol_yes);
		e2 = expr_alloc_symbol(&symbol_yes);
		break;
	default:
		;
	}
}

void expr_eliminate_eq(struct expr **ep1, struct expr **ep2)
{
	if (!e1 || !e2)
		return;
	switch (e1->type) {
	case E_OR:
	case E_AND:
		__expr_eliminate_eq(e1->type, ep1, ep2);
	default:
		;
	}
	if (e1->type != e2->type) switch (e2->type) {
	case E_OR:
	case E_AND:
		__expr_eliminate_eq(e2->type, ep1, ep2);
	default:
		;
	}
	e1 = expr_eliminate_yn(e1);
	e2 = expr_eliminate_yn(e2);
}

#undef e1
#undef e2

static int expr_eq(struct expr *e1, struct expr *e2)
{
	int res, old_count;

	if (e1->type != e2->type)
		return 0;
	switch (e1->type) {
	case E_EQUAL:
	case E_GEQ:
	case E_GTH:
	case E_LEQ:
	case E_LTH:
	case E_UNEQUAL:
		return e1->left.sym == e2->left.sym && e1->right.sym == e2->right.sym;
	case E_SYMBOL:
		return e1->left.sym == e2->left.sym;
	case E_NOT:
		return expr_eq(e1->left.expr, e2->left.expr);
	case E_AND:
	case E_OR:
		e1 = expr_copy(e1);
		e2 = expr_copy(e2);
		old_count = trans_count;
		expr_eliminate_eq(&e1, &e2);
		res = (e1->type == E_SYMBOL && e2->type == E_SYMBOL &&
		       e1->left.sym == e2->left.sym);
		expr_free(e1);
		expr_free(e2);
		trans_count = old_count;
		return res;
	case E_LIST:
	case E_RANGE:
	case E_NONE:
		/* panic */;
	}

	if (DEBUG_EXPR) {
		expr_fprint(e1, stdout);
		printf(" = ");
		expr_fprint(e2, stdout);
		printf(" ?\n");
	}

	return 0;
}

static struct expr *expr_eliminate_yn(struct expr *e)
{
	struct expr *tmp;

	if (e) switch (e->type) {
	case E_AND:
		e->left.expr = expr_eliminate_yn(e->left.expr);
		e->right.expr = expr_eliminate_yn(e->right.expr);
		if (e->left.expr->type == E_SYMBOL) {
			if (e->left.expr->left.sym == &symbol_no) {
				expr_free(e->left.expr);
				expr_free(e->right.expr);
				e->type = E_SYMBOL;
				e->left.sym = &symbol_no;
				e->right.expr = NULL;
				return e;
			} else if (e->left.expr->left.sym == &symbol_yes) {
				free(e->left.expr);
				tmp = e->right.expr;
				*e = *(e->right.expr);
				free(tmp);
				return e;
			}
		}
		if (e->right.expr->type == E_SYMBOL) {
			if (e->right.expr->left.sym == &symbol_no) {
				expr_free(e->left.expr);
				expr_free(e->right.expr);
				e->type = E_SYMBOL;
				e->left.sym = &symbol_no;
				e->right.expr = NULL;
				return e;
			} else if (e->right.expr->left.sym == &symbol_yes) {
				free(e->right.expr);
				tmp = e->left.expr;
				*e = *(e->left.expr);
				free(tmp);
				return e;
			}
		}
		break;
	case E_OR:
		e->left.expr = expr_eliminate_yn(e->left.expr);
		e->right.expr = expr_eliminate_yn(e->right.expr);
		if (e->left.expr->type == E_SYMBOL) {
			if (e->left.expr->left.sym == &symbol_no) {
				free(e->left.expr);
				tmp = e->right.expr;
				*e = *(e->right.expr);
				free(tmp);
				return e;
			} else if (e->left.expr->left.sym == &symbol_yes) {
				expr_free(e->left.expr);
				expr_free(e->right.expr);
				e->type = E_SYMBOL;
				e->left.sym = &symbol_yes;
				e->right.expr = NULL;
				return e;
			}
		}
		if (e->right.expr->type == E_SYMBOL) {
			if (e->right.expr->left.sym == &symbol_no) {
				free(e->right.expr);
				tmp = e->left.expr;
				*e = *(e->left.expr);
				free(tmp);
				return e;
			} else if (e->right.expr->left.sym == &symbol_yes) {
				expr_free(e->left.expr);
				expr_free(e->right.expr);
				e->type = E_SYMBOL;
				e->left.sym = &symbol_yes;
				e->right.expr = NULL;
				return e;
			}
		}
		break;
	default:
		;
	}
	return e;
}

/*
 * bool FOO!=n => FOO
 */
struct expr *expr_trans_bool(struct expr *e)
{
	if (!e)
		return NULL;
	switch (e->type) {
	case E_AND:
	case E_OR:
	case E_NOT:
		e->left.expr = expr_trans_bool(e->left.expr);
		e->right.expr = expr_trans_bool(e->right.expr);
		break;
	case E_UNEQUAL:
		// FOO!=n -> FOO
		if (e->left.sym->type == S_TRISTATE) {
			if (e->right.sym == &symbol_no) {
				e->type = E_SYMBOL;
				e->right.sym = NULL;
			}
		}
		break;
	default:
		;
	}
	return e;
}

/*
 * e1 || e2 -> ?
 */
static struct expr *expr_join_or(struct expr *e1, struct expr *e2)
{
	struct expr *tmp;
	struct symbol *sym1, *sym2;

	if (expr_eq(e1, e2))
		return expr_copy(e1);
	if (e1->type != E_EQUAL && e1->type != E_UNEQUAL && e1->type != E_SYMBOL && e1->type != E_NOT)
		return NULL;
	if (e2->type != E_EQUAL && e2->type != E_UNEQUAL && e2->type != E_SYMBOL && e2->type != E_NOT)
		return NULL;
	if (e1->type == E_NOT) {
		tmp = e1->left.expr;
		if (tmp->type != E_EQUAL && tmp->type != E_UNEQUAL && tmp->type != E_SYMBOL)
			return NULL;
		sym1 = tmp->left.sym;
	} else
		sym1 = e1->left.sym;
	if (e2->type == E_NOT) {
		if (e2->left.expr->type != E_SYMBOL)
			return NULL;
		sym2 = e2->left.expr->left.sym;
	} else
		sym2 = e2->left.sym;
	if (sym1 != sym2)
		return NULL;
	if (sym1->type != S_BOOLEAN && sym1->type != S_TRISTATE)
		return NULL;
	if (sym1->type == S_TRISTATE) {
		if (e1->type == E_EQUAL && e2->type == E_EQUAL &&
		    ((e1->right.sym == &symbol_yes && e2->right.sym == &symbol_mod) ||
		     (e1->right.sym == &symbol_mod && e2->right.sym == &symbol_yes))) {
			// (a='y') || (a='m') -> (a!='n')
			return expr_alloc_comp(E_UNEQUAL, sym1, &symbol_no);
		}
		if (e1->type == E_EQUAL && e2->type == E_EQUAL &&
		    ((e1->right.sym == &symbol_yes && e2->right.sym == &symbol_no) ||
		     (e1->right.sym == &symbol_no && e2->right.sym == &symbol_yes))) {
			// (a='y') || (a='n') -> (a!='m')
			return expr_alloc_comp(E_UNEQUAL, sym1, &symbol_mod);
		}
		if (e1->type == E_EQUAL && e2->type == E_EQUAL &&
		    ((e1->right.sym == &symbol_mod && e2->right.sym == &symbol_no) ||
		     (e1->right.sym == &symbol_no && e2->right.sym == &symbol_mod))) {
			// (a='m') || (a='n') -> (a!='y')
			return expr_alloc_comp(E_UNEQUAL, sym1, &symbol_yes);
		}
	}
	if (sym1->type == S_BOOLEAN && sym1 == sym2) {
		if ((e1->type == E_NOT && e1->left.expr->type == E_SYMBOL && e2->type == E_SYMBOL) ||
		    (e2->type == E_NOT && e2->left.expr->type == E_SYMBOL && e1->type == E_SYMBOL))
			return expr_alloc_symbol(&symbol_yes);
	}

	if (DEBUG_EXPR) {
		printf("optimize (");
		expr_fprint(e1, stdout);
		printf(") || (");
		expr_fprint(e2, stdout);
		printf(")?\n");
	}
	return NULL;
}

static struct expr *expr_join_and(struct expr *e1, struct expr *e2)
{
	struct expr *tmp;
	struct symbol *sym1, *sym2;

	if (expr_eq(e1, e2))
		return expr_copy(e1);
	if (e1->type != E_EQUAL && e1->type != E_UNEQUAL && e1->type != E_SYMBOL && e1->type != E_NOT)
		return NULL;
	if (e2->type != E_EQUAL && e2->type != E_UNEQUAL && e2->type != E_SYMBOL && e2->type != E_NOT)
		return NULL;
	if (e1->type == E_NOT) {
		tmp = e1->left.expr;
		if (tmp->type != E_EQUAL && tmp->type != E_UNEQUAL && tmp->type != E_SYMBOL)
			return NULL;
		sym1 = tmp->left.sym;
	} else
		sym1 = e1->left.sym;
	if (e2->type == E_NOT) {
		if (e2->left.expr->type != E_SYMBOL)
			return NULL;
		sym2 = e2->left.expr->left.sym;
	} else
		sym2 = e2->left.sym;
	if (sym1 != sym2)
		return NULL;
	if (sym1->type != S_BOOLEAN && sym1->type != S_TRISTATE)
		return NULL;

	if ((e1->type == E_SYMBOL && e2->type == E_EQUAL && e2->right.sym == &symbol_yes) ||
	    (e2->type == E_SYMBOL && e1->type == E_EQUAL && e1->right.sym == &symbol_yes))
		// (a) && (a='y') -> (a='y')
		return expr_alloc_comp(E_EQUAL, sym1, &symbol_yes);

	if ((e1->type == E_SYMBOL && e2->type == E_UNEQUAL && e2->right.sym == &symbol_no) ||
	    (e2->type == E_SYMBOL && e1->type == E_UNEQUAL && e1->right.sym == &symbol_no))
		// (a) && (a!='n') -> (a)
		return expr_alloc_symbol(sym1);

	if ((e1->type == E_SYMBOL && e2->type == E_UNEQUAL && e2->right.sym == &symbol_mod) ||
	    (e2->type == E_SYMBOL && e1->type == E_UNEQUAL && e1->right.sym == &symbol_mod))
		// (a) && (a!='m') -> (a='y')
		return expr_alloc_comp(E_EQUAL, sym1, &symbol_yes);

	if (sym1->type == S_TRISTATE) {
		if (e1->type == E_EQUAL && e2->type == E_UNEQUAL) {
			// (a='b') && (a!='c') -> 'b'='c' ? 'n' : a='b'
			sym2 = e1->right.sym;
			if ((e2->right.sym->flags & SYMBOL_CONST) && (sym2->flags & SYMBOL_CONST))
				return sym2 != e2->right.sym ? expr_alloc_comp(E_EQUAL, sym1, sym2)
							     : expr_alloc_symbol(&symbol_no);
		}
		if (e1->type == E_UNEQUAL && e2->type == E_EQUAL) {
			// (a='b') && (a!='c') -> 'b'='c' ? 'n' : a='b'
			sym2 = e2->right.sym;
			if ((e1->right.sym->flags & SYMBOL_CONST) && (sym2->flags & SYMBOL_CONST))
				return sym2 != e1->right.sym ? expr_alloc_comp(E_EQUAL, sym1, sym2)
							     : expr_alloc_symbol(&symbol_no);
		}
		if (e1->type == E_UNEQUAL && e2->type == E_UNEQUAL &&
			   ((e1->right.sym == &symbol_yes && e2->right.sym == &symbol_no) ||
			    (e1->right.sym == &symbol_no && e2->right.sym == &symbol_yes)))
			// (a!='y') && (a!='n') -> (a='m')
			return expr_alloc_comp(E_EQUAL, sym1, &symbol_mod);

		if (e1->type == E_UNEQUAL && e2->type == E_UNEQUAL &&
			   ((e1->right.sym == &symbol_yes && e2->right.sym == &symbol_mod) ||
			    (e1->right.sym == &symbol_mod && e2->right.sym == &symbol_yes)))
			// (a!='y') && (a!='m') -> (a='n')
			return expr_alloc_comp(E_EQUAL, sym1, &symbol_no);

		if (e1->type == E_UNEQUAL && e2->type == E_UNEQUAL &&
			   ((e1->right.sym == &symbol_mod && e2->right.sym == &symbol_no) ||
			    (e1->right.sym == &symbol_no && e2->right.sym == &symbol_mod)))
			// (a!='m') && (a!='n') -> (a='m')
			return expr_alloc_comp(E_EQUAL, sym1, &symbol_yes);

		if ((e1->type == E_SYMBOL && e2->type == E_EQUAL && e2->right.sym == &symbol_mod) ||
		    (e2->type == E_SYMBOL && e1->type == E_EQUAL && e1->right.sym == &symbol_mod) ||
		    (e1->type == E_SYMBOL && e2->type == E_UNEQUAL && e2->right.sym == &symbol_yes) ||
		    (e2->type == E_SYMBOL && e1->type == E_UNEQUAL && e1->right.sym == &symbol_yes))
			return NULL;
	}

	if (DEBUG_EXPR) {
		printf("optimize (");
		expr_fprint(e1, stdout);
		printf(") && (");
		expr_fprint(e2, stdout);
		printf(")?\n");
	}
	return NULL;
}

static void expr_eliminate_dups1(enum expr_type type, struct expr **ep1, struct expr **ep2)
{
#define e1 (*ep1)
#define e2 (*ep2)
	struct expr *tmp;

	if (e1->type == type) {
		expr_eliminate_dups1(type, &e1->left.expr, &e2);
		expr_eliminate_dups1(type, &e1->right.expr, &e2);
		return;
	}
	if (e2->type == type) {
		expr_eliminate_dups1(type, &e1, &e2->left.expr);
		expr_eliminate_dups1(type, &e1, &e2->right.expr);
		return;
	}
	if (e1 == e2)
		return;

	switch (e1->type) {
	case E_OR: case E_AND:
		expr_eliminate_dups1(e1->type, &e1, &e1);
	default:
		;
	}

	switch (type) {
	case E_OR:
		tmp = expr_join_or(e1, e2);
		if (tmp) {
			expr_free(e1); expr_free(e2);
			e1 = expr_alloc_symbol(&symbol_no);
			e2 = tmp;
			trans_count++;
		}
		break;
	case E_AND:
		tmp = expr_join_and(e1, e2);
		if (tmp) {
			expr_free(e1); expr_free(e2);
			e1 = expr_alloc_symbol(&symbol_yes);
			e2 = tmp;
			trans_count++;
		}
		break;
	default:
		;
	}
#undef e1
#undef e2
}

struct expr *expr_eliminate_dups(struct expr *e)
{
	int oldcount;
	if (!e)
		return e;

	oldcount = trans_count;
	while (1) {
		trans_count = 0;
		switch (e->type) {
		case E_OR: case E_AND:
			expr_eliminate_dups1(e->type, &e, &e);
		default:
			;
		}
		if (!trans_count)
			break;
		e = expr_eliminate_yn(e);
	}
	trans_count = oldcount;
	return e;
}

struct expr *expr_transform(struct expr *e)
{
	struct expr *tmp;

	if (!e)
		return NULL;
	switch (e->type) {
	case E_EQUAL:
	case E_GEQ:
	case E_GTH:
	case E_LEQ:
	case E_LTH:
	case E_UNEQUAL:
	case E_SYMBOL:
	case E_LIST:
		break;
	default:
		e->left.expr = expr_transform(e->left.expr);
		e->right.expr = expr_transform(e->right.expr);
	}

	switch (e->type) {
	case E_EQUAL:
		if (e->left.sym->type != S_BOOLEAN)
			break;
		if (e->right.sym == &symbol_no) {
			e->type = E_NOT;
			e->left.expr = expr_alloc_symbol(e->left.sym);
			e->right.sym = NULL;
			break;
		}
		if (e->right.sym == &symbol_mod) {
			printf("boolean symbol %s tested for 'm'? test forced to 'n'\n", e->left.sym->name);
			e->type = E_SYMBOL;
			e->left.sym = &symbol_no;
			e->right.sym = NULL;
			break;
		}
		if (e->right.sym == &symbol_yes) {
			e->type = E_SYMBOL;
			e->right.sym = NULL;
			break;
		}
		break;
	case E_UNEQUAL:
		if (e->left.sym->type != S_BOOLEAN)
			break;
		if (e->right.sym == &symbol_no) {
			e->type = E_SYMBOL;
			e->right.sym = NULL;
			break;
		}
		if (e->right.sym == &symbol_mod) {
			printf("boolean symbol %s tested for 'm'? test forced to 'y'\n", e->left.sym->name);
			e->type = E_SYMBOL;
			e->left.sym = &symbol_yes;
			e->right.sym = NULL;
			break;
		}
		if (e->right.sym == &symbol_yes) {
			e->type = E_NOT;
			e->left.expr = expr_alloc_symbol(e->left.sym);
			e->right.sym = NULL;
			break;
		}
		break;
	case E_NOT:
		switch (e->left.expr->type) {
		case E_NOT:
			// !!a -> a
			tmp = e->left.expr->left.expr;
			free(e->left.expr);
			free(e);
			e = tmp;
			e = expr_transform(e);
			break;
		case E_EQUAL:
		case E_UNEQUAL:
			// !a='x' -> a!='x'
			tmp = e->left.expr;
			free(e);
			e = tmp;
			e->type = e->type == E_EQUAL ? E_UNEQUAL : E_EQUAL;
			break;
		case E_LEQ:
		case E_GEQ:
			// !a<='x' -> a>'x'
			tmp = e->left.expr;
			free(e);
			e = tmp;
			e->type = e->type == E_LEQ ? E_GTH : E_LTH;
			break;
		case E_LTH:
		case E_GTH:
			// !a<'x' -> a>='x'
			tmp = e->left.expr;
			free(e);
			e = tmp;
			e->type = e->type == E_LTH ? E_GEQ : E_LEQ;
			break;
		case E_OR:
			// !(a || b) -> !a && !b
			tmp = e->left.expr;
			e->type = E_AND;
			e->right.expr = expr_alloc_one(E_NOT, tmp->right.expr);
			tmp->type = E_NOT;
			tmp->right.expr = NULL;
			e = expr_transform(e);
			break;
		case E_AND:
			// !(a && b) -> !a || !b
			tmp = e->left.expr;
			e->type = E_OR;
			e->right.expr = expr_alloc_one(E_NOT, tmp->right.expr);
			tmp->type = E_NOT;
			tmp->right.expr = NULL;
			e = expr_transform(e);
			break;
		case E_SYMBOL:
			if (e->left.expr->left.sym == &symbol_yes) {
				// !'y' -> 'n'
				tmp = e->left.expr;
				free(e);
				e = tmp;
				e->type = E_SYMBOL;
				e->left.sym = &symbol_no;
				break;
			}
			if (e->left.expr->left.sym == &symbol_mod) {
				// !'m' -> 'm'
				tmp = e->left.expr;
				free(e);
				e = tmp;
				e->type = E_SYMBOL;
				e->left.sym = &symbol_mod;
				break;
			}
			if (e->left.expr->left.sym == &symbol_no) {
				// !'n' -> 'y'
				tmp = e->left.expr;
				free(e);
				e = tmp;
				e->type = E_SYMBOL;
				e->left.sym = &symbol_yes;
				break;
			}
			break;
		default:
			;
		}
		break;
	default:
		;
	}
	return e;
}

int expr_contains_symbol(struct expr *dep, struct symbol *sym)
{
	if (!dep)
		return 0;

	switch (dep->type) {
	case E_AND:
	case E_OR:
		return expr_contains_symbol(dep->left.expr, sym) ||
		       expr_contains_symbol(dep->right.expr, sym);
	case E_SYMBOL:
		return dep->left.sym == sym;
	case E_EQUAL:
	case E_GEQ:
	case E_GTH:
	case E_LEQ:
	case E_LTH:
	case E_UNEQUAL:
		return dep->left.sym == sym ||
		       dep->right.sym == sym;
	case E_NOT:
		return expr_contains_symbol(dep->left.expr, sym);
	default:
		;
	}
	return 0;
}

bool expr_depends_symbol(struct expr *dep, struct symbol *sym)
{
	if (!dep)
		return false;

	switch (dep->type) {
	case E_AND:
		return expr_depends_symbol(dep->left.expr, sym) ||
		       expr_depends_symbol(dep->right.expr, sym);
	case E_SYMBOL:
		return dep->left.sym == sym;
	case E_EQUAL:
		if (dep->left.sym == sym) {
			if (dep->right.sym == &symbol_yes || dep->right.sym == &symbol_mod)
				return true;
		}
		break;
	case E_UNEQUAL:
		if (dep->left.sym == sym) {
			if (dep->right.sym == &symbol_no)
				return true;
		}
		break;
	default:
		;
	}
 	return false;
}

struct expr *expr_trans_compare(struct expr *e, enum expr_type type, struct symbol *sym)
{
	struct expr *e1, *e2;

	if (!e) {
		e = expr_alloc_symbol(sym);
		if (type == E_UNEQUAL)
			e = expr_alloc_one(E_NOT, e);
		return e;
	}
	switch (e->type) {
	case E_AND:
		e1 = expr_trans_compare(e->left.expr, E_EQUAL, sym);
		e2 = expr_trans_compare(e->right.expr, E_EQUAL, sym);
		if (sym == &symbol_yes)
			e = expr_alloc_two(E_AND, e1, e2);
		if (sym == &symbol_no)
			e = expr_alloc_two(E_OR, e1, e2);
		if (type == E_UNEQUAL)
			e = expr_alloc_one(E_NOT, e);
		return e;
	case E_OR:
		e1 = expr_trans_compare(e->left.expr, E_EQUAL, sym);
		e2 = expr_trans_compare(e->right.expr, E_EQUAL, sym);
		if (sym == &symbol_yes)
			e = expr_alloc_two(E_OR, e1, e2);
		if (sym == &symbol_no)
			e = expr_alloc_two(E_AND, e1, e2);
		if (type == E_UNEQUAL)
			e = expr_alloc_one(E_NOT, e);
		return e;
	case E_NOT:
		return expr_trans_compare(e->left.expr, type == E_EQUAL ? E_UNEQUAL : E_EQUAL, sym);
	case E_UNEQUAL:
	case E_LTH:
	case E_LEQ:
	case E_GTH:
	case E_GEQ:
	case E_EQUAL:
		if (type == E_EQUAL) {
			if (sym == &symbol_yes)
				return expr_copy(e);
			if (sym == &symbol_mod)
				return expr_alloc_symbol(&symbol_no);
			if (sym == &symbol_no)
				return expr_alloc_one(E_NOT, expr_copy(e));
		} else {
			if (sym == &symbol_yes)
				return expr_alloc_one(E_NOT, expr_copy(e));
			if (sym == &symbol_mod)
				return expr_alloc_symbol(&symbol_yes);
			if (sym == &symbol_no)
				return expr_copy(e);
		}
		break;
	case E_SYMBOL:
		return expr_alloc_comp(type, e->left.sym, sym);
	case E_LIST:
	case E_RANGE:
	case E_NONE:
		/* panic */;
	}
	return NULL;
}

enum string_value_kind {
	k_string,
	k_signed,
	k_unsigned,
	k_invalid
};

union string_value {
	unsigned long long u;
	signed long long s;
};

static enum string_value_kind expr_parse_string(const char *str,
						enum symbol_type type,
						union string_value *val)
{
	char *tail;
	enum string_value_kind kind;

	errno = 0;
	switch (type) {
	case S_BOOLEAN:
	case S_TRISTATE:
		return k_string;
	case S_INT:
		val->s = strtoll(str, &tail, 10);
		kind = k_signed;
		break;
	case S_HEX:
		val->u = strtoull(str, &tail, 16);
		kind = k_unsigned;
		break;
	case S_STRING:
	case S_UNKNOWN:
		val->s = strtoll(str, &tail, 0);
		kind = k_signed;
		break;
	default:
		return k_invalid;
	}
	return !errno && !*tail && tail > str && isxdigit(tail[-1])
	       ? kind : k_string;
}

tristate expr_calc_value(struct expr *e)
{
	tristate val1, val2;
	const char *str1, *str2;
	enum string_value_kind k1 = k_string, k2 = k_string;
	union string_value lval = {}, rval = {};
	int res;

	if (!e)
		return yes;

	switch (e->type) {
	case E_SYMBOL:
		sym_calc_value(e->left.sym);
		return e->left.sym->curr.tri;
	case E_AND:
		val1 = expr_calc_value(e->left.expr);
		val2 = expr_calc_value(e->right.expr);
		return EXPR_AND(val1, val2);
	case E_OR:
		val1 = expr_calc_value(e->left.expr);
		val2 = expr_calc_value(e->right.expr);
		return EXPR_OR(val1, val2);
	case E_NOT:
		val1 = expr_calc_value(e->left.expr);
		return EXPR_NOT(val1);
	case E_EQUAL:
	case E_GEQ:
	case E_GTH:
	case E_LEQ:
	case E_LTH:
	case E_UNEQUAL:
		break;
	default:
		printf("expr_calc_value: %d?\n", e->type);
		return no;
	}

	sym_calc_value(e->left.sym);
	sym_calc_value(e->right.sym);
	str1 = sym_get_string_value(e->left.sym);
	str2 = sym_get_string_value(e->right.sym);

	if (e->left.sym->type != S_STRING || e->right.sym->type != S_STRING) {
		k1 = expr_parse_string(str1, e->left.sym->type, &lval);
		k2 = expr_parse_string(str2, e->right.sym->type, &rval);
	}

	if (k1 == k_string || k2 == k_string)
		res = strcmp(str1, str2);
	else if (k1 == k_invalid || k2 == k_invalid) {
		if (e->type != E_EQUAL && e->type != E_UNEQUAL) {
			printf("Cannot compare \"%s\" and \"%s\"\n", str1, str2);
			return no;
		}
		res = strcmp(str1, str2);
	} else if (k1 == k_unsigned || k2 == k_unsigned)
		res = (lval.u > rval.u) - (lval.u < rval.u);
	else /* if (k1 == k_signed && k2 == k_signed) */
		res = (lval.s > rval.s) - (lval.s < rval.s);

	switch(e->type) {
	case E_EQUAL:
		return res ? no : yes;
	case E_GEQ:
		return res >= 0 ? yes : no;
	case E_GTH:
		return res > 0 ? yes : no;
	case E_LEQ:
		return res <= 0 ? yes : no;
	case E_LTH:
		return res < 0 ? yes : no;
	case E_UNEQUAL:
		return res ? yes : no;
	default:
		printf("expr_calc_value: relation %d?\n", e->type);
		return no;
	}
}

static int expr_compare_type(enum expr_type t1, enum expr_type t2)
{
	if (t1 == t2)
		return 0;
	switch (t1) {
	case E_LEQ:
	case E_LTH:
	case E_GEQ:
	case E_GTH:
		if (t2 == E_EQUAL || t2 == E_UNEQUAL)
			return 1;
	case E_EQUAL:
	case E_UNEQUAL:
		if (t2 == E_NOT)
			return 1;
	case E_NOT:
		if (t2 == E_AND)
			return 1;
	case E_AND:
		if (t2 == E_OR)
			return 1;
	case E_OR:
		if (t2 == E_LIST)
			return 1;
	case E_LIST:
		if (t2 == 0)
			return 1;
	default:
		return -1;
	}
	printf("[%dgt%d?]", t1, t2);
	return 0;
}

static inline struct expr *
expr_get_leftmost_symbol(const struct expr *e)
{

	if (e == NULL)
		return NULL;

	while (e->type != E_SYMBOL)
		e = e->left.expr;

	return expr_copy(e);
}

/*
 * Given expression `e1' and `e2', returns the leaf of the longest
 * sub-expression of `e1' not containing 'e2.
 */
struct expr *expr_simplify_unmet_dep(struct expr *e1, struct expr *e2)
{
	struct expr *ret;

	switch (e1->type) {
	case E_OR:
		return expr_alloc_and(
		    expr_simplify_unmet_dep(e1->left.expr, e2),
		    expr_simplify_unmet_dep(e1->right.expr, e2));
	case E_AND: {
		struct expr *e;
		e = expr_alloc_and(expr_copy(e1), expr_copy(e2));
		e = expr_eliminate_dups(e);
		ret = (!expr_eq(e, e1)) ? e1 : NULL;
		expr_free(e);
		break;
		}
	default:
		ret = e1;
		break;
	}

	return expr_get_leftmost_symbol(ret);
}

void expr_print(struct expr *e, void (*fn)(void *, struct symbol *, const char *), void *data, int prevtoken)
{
	if (!e) {
		fn(data, NULL, "y");
		return;
	}

	if (expr_compare_type(prevtoken, e->type) > 0)
		fn(data, NULL, "(");
	switch (e->type) {
	case E_SYMBOL:
		if (e->left.sym->name)
			fn(data, e->left.sym, e->left.sym->name);
		else
			fn(data, NULL, "<choice>");
		break;
	case E_NOT:
		fn(data, NULL, "!");
		expr_print(e->left.expr, fn, data, E_NOT);
		break;
	case E_EQUAL:
		if (e->left.sym->name)
			fn(data, e->left.sym, e->left.sym->name);
		else
			fn(data, NULL, "<choice>");
		fn(data, NULL, "=");
		fn(data, e->right.sym, e->right.sym->name);
		break;
	case E_LEQ:
	case E_LTH:
		if (e->left.sym->name)
			fn(data, e->left.sym, e->left.sym->name);
		else
			fn(data, NULL, "<choice>");
		fn(data, NULL, e->type == E_LEQ ? "<=" : "<");
		fn(data, e->right.sym, e->right.sym->name);
		break;
	case E_GEQ:
	case E_GTH:
		if (e->left.sym->name)
			fn(data, e->left.sym, e->left.sym->name);
		else
			fn(data, NULL, "<choice>");
		fn(data, NULL, e->type == E_GEQ ? ">=" : ">");
		fn(data, e->right.sym, e->right.sym->name);
		break;
	case E_UNEQUAL:
		if (e->left.sym->name)
			fn(data, e->left.sym, e->left.sym->name);
		else
			fn(data, NULL, "<choice>");
		fn(data, NULL, "!=");
		fn(data, e->right.sym, e->right.sym->name);
		break;
	case E_OR:
		expr_print(e->left.expr, fn, data, E_OR);
		fn(data, NULL, " || ");
		expr_print(e->right.expr, fn, data, E_OR);
		break;
	case E_AND:
		expr_print(e->left.expr, fn, data, E_AND);
		fn(data, NULL, " && ");
		expr_print(e->right.expr, fn, data, E_AND);
		break;
	case E_LIST:
		fn(data, e->right.sym, e->right.sym->name);
		if (e->left.expr) {
			fn(data, NULL, " ^ ");
			expr_print(e->left.expr, fn, data, E_LIST);
		}
		break;
	case E_RANGE:
		fn(data, NULL, "[");
		fn(data, e->left.sym, e->left.sym->name);
		fn(data, NULL, " ");
		fn(data, e->right.sym, e->right.sym->name);
		fn(data, NULL, "]");
		break;
	default:
	  {
		char buf[32];
		sprintf(buf, "<unknown type %d>", e->type);
		fn(data, NULL, buf);
		break;
	  }
	}
	if (expr_compare_type(prevtoken, e->type) > 0)
		fn(data, NULL, ")");
}

static void expr_print_file_helper(void *data, struct symbol *sym, const char *str)
{
	xfwrite(str, strlen(str), 1, data);
}

void expr_fprint(struct expr *e, FILE *out)
{
	expr_print(e, expr_print_file_helper, out, E_NONE);
}

static void expr_print_gstr_helper(void *data, struct symbol *sym, const char *str)
{
	struct gstr *gs = (struct gstr*)data;
	const char *sym_str = NULL;

	if (sym)
		sym_str = sym_get_string_value(sym);

	if (gs->max_width) {
		unsigned extra_length = strlen(str);
		const char *last_cr = strrchr(gs->s, '\n');
		unsigned last_line_length;

		if (sym_str)
			extra_length += 4 + strlen(sym_str);

		if (!last_cr)
			last_cr = gs->s;

		last_line_length = strlen(gs->s) - (last_cr - gs->s);

		if ((last_line_length + extra_length) > gs->max_width)
			str_append(gs, "\\\n");
	}

	str_append(gs, str);
	if (sym && sym->type != S_UNKNOWN)
		str_printf(gs, " [=%s]", sym_str);
}

void expr_gstr_print(struct expr *e, struct gstr *gs)
{
	expr_print(e, expr_print_gstr_helper, gs, E_NONE);
}
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