Bug Summary

File:src/usr.bin/lex/sym.c
Warning:line 105, column 19
Access to field 'next' results in a dereference of a null pointer (loaded from variable 'new_entry')

Annotated Source Code

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clang -cc1 -cc1 -triple amd64-unknown-openbsd7.0 -analyze -disable-free -disable-llvm-verifier -discard-value-names -main-file-name sym.c -analyzer-store=region -analyzer-opt-analyze-nested-blocks -analyzer-checker=core -analyzer-checker=apiModeling -analyzer-checker=unix -analyzer-checker=deadcode -analyzer-checker=security.insecureAPI.UncheckedReturn -analyzer-checker=security.insecureAPI.getpw -analyzer-checker=security.insecureAPI.gets -analyzer-checker=security.insecureAPI.mktemp -analyzer-checker=security.insecureAPI.mkstemp -analyzer-checker=security.insecureAPI.vfork -analyzer-checker=nullability.NullPassedToNonnull -analyzer-checker=nullability.NullReturnedFromNonnull -analyzer-output plist -w -setup-static-analyzer -mrelocation-model pic -pic-level 1 -pic-is-pie -mframe-pointer=all -relaxed-aliasing -fno-rounding-math -mconstructor-aliases -munwind-tables -target-cpu x86-64 -target-feature +retpoline-indirect-calls -target-feature +retpoline-indirect-branches -tune-cpu generic -debugger-tuning=gdb -fcoverage-compilation-dir=/usr/src/usr.bin/lex/obj -resource-dir /usr/local/lib/clang/13.0.0 -I . -I /usr/src/usr.bin/lex -D HAVE_CONFIG_H -internal-isystem /usr/local/lib/clang/13.0.0/include -internal-externc-isystem /usr/include -O2 -fdebug-compilation-dir=/usr/src/usr.bin/lex/obj -ferror-limit 19 -fwrapv -D_RET_PROTECTOR -ret-protector -fgnuc-version=4.2.1 -vectorize-loops -vectorize-slp -fno-builtin-malloc -fno-builtin-calloc -fno-builtin-realloc -fno-builtin-valloc -fno-builtin-free -fno-builtin-strdup -fno-builtin-strndup -analyzer-output=html -faddrsig -D__GCC_HAVE_DWARF2_CFI_ASM=1 -o /home/ben/Projects/vmm/scan-build/2022-01-12-194120-40624-1 -x c /usr/src/usr.bin/lex/sym.c
1/* $OpenBSD: sym.c,v 1.9 2015/11/19 23:34:56 mmcc Exp $ */
2
3/* sym - symbol table routines */
4
5/* Copyright (c) 1990 The Regents of the University of California. */
6/* All rights reserved. */
7
8/* This code is derived from software contributed to Berkeley by */
9/* Vern Paxson. */
10
11/* The United States Government has rights in this work pursuant */
12/* to contract no. DE-AC03-76SF00098 between the United States */
13/* Department of Energy and the University of California. */
14
15/* This file is part of flex. */
16
17/* Redistribution and use in source and binary forms, with or without */
18/* modification, are permitted provided that the following conditions */
19/* are met: */
20
21/* 1. Redistributions of source code must retain the above copyright */
22/* notice, this list of conditions and the following disclaimer. */
23/* 2. Redistributions in binary form must reproduce the above copyright */
24/* notice, this list of conditions and the following disclaimer in the */
25/* documentation and/or other materials provided with the distribution. */
26
27/* Neither the name of the University nor the names of its contributors */
28/* may be used to endorse or promote products derived from this software */
29/* without specific prior written permission. */
30
31/* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR */
32/* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED */
33/* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR */
34/* PURPOSE. */
35
36#include "flexdef.h"
37
38/* Variables for symbol tables:
39 * sctbl - start-condition symbol table
40 * ndtbl - name-definition symbol table
41 * ccltab - character class text symbol table
42 */
43
44struct hash_entry {
45 struct hash_entry *prev, *next;
46 char *name;
47 char *str_val;
48 int int_val;
49};
50
51typedef struct hash_entry **hash_table;
52
53#define NAME_TABLE_HASH_SIZE101 101
54#define START_COND_HASH_SIZE101 101
55#define CCL_HASH_SIZE101 101
56
57static struct hash_entry *ndtbl[NAME_TABLE_HASH_SIZE101];
58static struct hash_entry *sctbl[START_COND_HASH_SIZE101];
59static struct hash_entry *ccltab[CCL_HASH_SIZE101];
60
61
62/* declare functions that have forward references */
63
64static int addsym PROTO ((char[], char *, int, hash_table, int))(char[], char *, int, hash_table, int);
65static struct hash_entry *findsym PROTO ((const char *sym,(const char *sym, hash_table table, int table_size)
66 hash_table table,(const char *sym, hash_table table, int table_size)
67
68 int table_size))(const char *sym, hash_table table, int table_size);
69static int hashfunct PROTO ((const char *, int))(const char *, int);
70
71
72/* addsym - add symbol and definitions to symbol table
73 *
74 * -1 is returned if the symbol already exists, and the change not made.
75 */
76
77static int addsym (sym, str_def, int_def, table, table_size)
78 char sym[];
79 char *str_def;
80 int int_def;
81 hash_table table;
82 int table_size;
83{
84 int hash_val = hashfunct (sym, table_size);
85 struct hash_entry *sym_entry = table[hash_val];
86 struct hash_entry *new_entry;
87 struct hash_entry *successor;
88
89 while (sym_entry) {
4
←
Loop condition is false. Execution continues on line 99
→
90 if (!strcmp (sym, sym_entry->name)) { /* entry already exists */
91 return -1;
92 }
93
94 sym_entry = sym_entry->next;
95 }
96
97 /* create new entry */
98 new_entry = (struct hash_entry *)
5
←
Value assigned to 'new_entry'
→
99 malloc (sizeof (struct hash_entry));
100
101 if (new_entry == NULL((void *)0))
6
←
Assuming 'new_entry' is equal to NULL
→
7
←
Taking true branch
→
102 flexfatal (_("symbol table memory allocation failed")"symbol table memory allocation failed");
103
104 if ((successor = table[hash_val]) != 0) {
8
←
Assuming the condition is true
→
9
←
Taking true branch
→
105 new_entry->next = successor;
10
←
Access to field 'next' results in a dereference of a null pointer (loaded from variable 'new_entry')
106 successor->prev = new_entry;
107 }
108 else
109 new_entry->next = NULL((void *)0);
110
111 new_entry->prev = NULL((void *)0);
112 new_entry->name = sym;
113 new_entry->str_val = str_def;
114 new_entry->int_val = int_def;
115
116 table[hash_val] = new_entry;
117
118 return 0;
119}
120
121
122/* cclinstal - save the text of a character class */
123
124void cclinstal (ccltxt, cclnum)
125 u_char ccltxt[];
126 int cclnum;
127{
128 /* We don't bother checking the return status because we are not
129 * called unless the symbol is new.
130 */
131
132 (void) addsym ((char *) copy_unsigned_string (ccltxt),
133 (char *) 0, cclnum, ccltab, CCL_HASH_SIZE101);
134}
135
136
137/* ccllookup - lookup the number associated with character class text
138 *
139 * Returns 0 if there's no CCL associated with the text.
140 */
141
142int ccllookup (ccltxt)
143 u_char ccltxt[];
144{
145 return findsym ((char *) ccltxt, ccltab, CCL_HASH_SIZE101)->int_val;
146}
147
148
149/* findsym - find symbol in symbol table */
150
151static struct hash_entry *findsym (sym, table, table_size)
152 const char *sym;
153 hash_table table;
154 int table_size;
155{
156 static struct hash_entry empty_entry = {
157 (struct hash_entry *) 0, (struct hash_entry *) 0,
158 (char *) 0, (char *) 0, 0,
159 };
160 struct hash_entry *sym_entry =
161
162 table[hashfunct (sym, table_size)];
163
164 while (sym_entry) {
165 if (!strcmp (sym, sym_entry->name))
166 return sym_entry;
167 sym_entry = sym_entry->next;
168 }
169
170 return &empty_entry;
171}
172
173/* hashfunct - compute the hash value for "str" and hash size "hash_size" */
174
175static int hashfunct (str, hash_size)
176 const char *str;
177 int hash_size;
178{
179 int hashval;
180 int locstr;
181
182 hashval = 0;
183 locstr = 0;
184
185 while (str[locstr]) {
186 hashval = (hashval << 1) + (unsigned char) str[locstr++];
187 hashval %= hash_size;
188 }
189
190 return hashval;
191}
192
193
194/* ndinstal - install a name definition */
195
196void ndinstal (name, definition)
197 const char *name;
198 u_char definition[];
199{
200
201 if (addsym (copy_string (name),
202 (char *) copy_unsigned_string (definition), 0,
203 ndtbl, NAME_TABLE_HASH_SIZE101))
204 synerr (_("name defined twice")"name defined twice");
205}
206
207
208/* ndlookup - lookup a name definition
209 *
210 * Returns a nil pointer if the name definition does not exist.
211 */
212
213u_char *ndlookup (nd)
214 const char *nd;
215{
216 return (u_char *) findsym (nd, ndtbl, NAME_TABLE_HASH_SIZE101)->str_val;
217}
218
219
220/* scextend - increase the maximum number of start conditions */
221
222void scextend ()
223{
224 current_max_scs += MAX_SCS_INCREMENT40;
225
226 ++num_reallocs;
227
228 scset = reallocate_integer_array (scset, current_max_scs)(int *) reallocate_array( (void *) scset, current_max_scs, sizeof
( int ) );
229 scbol = reallocate_integer_array (scbol, current_max_scs)(int *) reallocate_array( (void *) scbol, current_max_scs, sizeof
( int ) );
230 scxclu = reallocate_integer_array (scxclu, current_max_scs)(int *) reallocate_array( (void *) scxclu, current_max_scs, sizeof
( int ) );
231 sceof = reallocate_integer_array (sceof, current_max_scs)(int *) reallocate_array( (void *) sceof, current_max_scs, sizeof
( int ) );
232 scname = reallocate_char_ptr_array (scname, current_max_scs)(char **) reallocate_array( (void *) scname, current_max_scs,
sizeof( char * ) );
233}
234
235
236/* scinstal - make a start condition
237 *
238 * NOTE
239 * The start condition is "exclusive" if xcluflg is true.
240 */
241
242void scinstal (str, xcluflg)
243 const char *str;
244 int xcluflg;
245{
246
247 if (++lastsc >= current_max_scs)
1
Assuming the condition is false
→
2
←
Taking false branch
→
248 scextend ();
249
250 scname[lastsc] = copy_string (str);
251
252 if (addsym (scname[lastsc], (char *) 0, lastsc,
3
←
Calling 'addsym'
→
253 sctbl, START_COND_HASH_SIZE101))
254 format_pinpoint_message (_"start condition %s declared twice"
255 ("start condition %s declared twice")"start condition %s declared twice",
256str);
257
258 scset[lastsc] = mkstate (SYM_EPSILON(256 + 1));
259 scbol[lastsc] = mkstate (SYM_EPSILON(256 + 1));
260 scxclu[lastsc] = xcluflg;
261 sceof[lastsc] = false0;
262}
263
264
265/* sclookup - lookup the number associated with a start condition
266 *
267 * Returns 0 if no such start condition.
268 */
269
270int sclookup (str)
271 const char *str;
272{
273 return findsym (str, sctbl, START_COND_HASH_SIZE101)->int_val;
274}