1 /*- 2 * Copyright (c) 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * This code is derived from software contributed to Berkeley by 6 * Kenneth Almquist. 7 * 8 * %sccs.include.redist.c% 9 */ 10 11 #ifndef lint 12 static char sccsid[] = "@(#)alias.c 8.3 (Berkeley) 05/04/95"; 13 #endif /* not lint */ 14 15 #include <stdlib.h> 16 #include "shell.h" 17 #include "input.h" 18 #include "output.h" 19 #include "error.h" 20 #include "memalloc.h" 21 #include "mystring.h" 22 #include "alias.h" 23 #include "options.h" /* XXX for argptr (should remove?) */ 24 25 #define ATABSIZE 39 26 27 struct alias *atab[ATABSIZE]; 28 29 STATIC void setalias __P((char *, char *)); 30 STATIC int unalias __P((char *)); 31 STATIC struct alias **hashalias __P((char *)); 32 33 STATIC 34 void 35 setalias(name, val) 36 char *name, *val; 37 { 38 struct alias *ap, **app; 39 40 app = hashalias(name); 41 for (ap = *app; ap; ap = ap->next) { 42 if (equal(name, ap->name)) { 43 INTOFF; 44 ckfree(ap->val); 45 ap->val = savestr(val); 46 INTON; 47 return; 48 } 49 } 50 /* not found */ 51 INTOFF; 52 ap = ckmalloc(sizeof (struct alias)); 53 ap->name = savestr(name); 54 /* 55 * XXX - HACK: in order that the parser will not finish reading the 56 * alias value off the input before processing the next alias, we 57 * dummy up an extra space at the end of the alias. This is a crock 58 * and should be re-thought. The idea (if you feel inclined to help) 59 * is to avoid alias recursions. The mechanism used is: when 60 * expanding an alias, the value of the alias is pushed back on the 61 * input as a string and a pointer to the alias is stored with the 62 * string. The alias is marked as being in use. When the input 63 * routine finishes reading the string, it markes the alias not 64 * in use. The problem is synchronization with the parser. Since 65 * it reads ahead, the alias is marked not in use before the 66 * resulting token(s) is next checked for further alias sub. The 67 * H A C K is that we add a little fluff after the alias value 68 * so that the string will not be exhausted. This is a good 69 * idea ------- ***NOT*** 70 */ 71 #ifdef notyet 72 ap->val = savestr(val); 73 #else /* hack */ 74 { 75 int len = strlen(val); 76 ap->val = ckmalloc(len + 2); 77 memcpy(ap->val, val, len); 78 ap->val[len] = ' '; /* fluff */ 79 ap->val[len+1] = '\0'; 80 } 81 #endif 82 ap->next = *app; 83 *app = ap; 84 INTON; 85 } 86 87 STATIC int 88 unalias(name) 89 char *name; 90 { 91 struct alias *ap, **app; 92 93 app = hashalias(name); 94 95 for (ap = *app; ap; app = &(ap->next), ap = ap->next) { 96 if (equal(name, ap->name)) { 97 /* 98 * if the alias is currently in use (i.e. its 99 * buffer is being used by the input routine) we 100 * just null out the name instead of freeing it. 101 * We could clear it out later, but this situation 102 * is so rare that it hardly seems worth it. 103 */ 104 if (ap->flag & ALIASINUSE) 105 *ap->name = '\0'; 106 else { 107 INTOFF; 108 *app = ap->next; 109 ckfree(ap->name); 110 ckfree(ap->val); 111 ckfree(ap); 112 INTON; 113 } 114 return (0); 115 } 116 } 117 118 return (1); 119 } 120 121 #ifdef mkinit 122 MKINIT void rmaliases(); 123 124 SHELLPROC { 125 rmaliases(); 126 } 127 #endif 128 129 void 130 rmaliases() { 131 struct alias *ap, *tmp; 132 int i; 133 134 INTOFF; 135 for (i = 0; i < ATABSIZE; i++) { 136 ap = atab[i]; 137 atab[i] = NULL; 138 while (ap) { 139 ckfree(ap->name); 140 ckfree(ap->val); 141 tmp = ap; 142 ap = ap->next; 143 ckfree(tmp); 144 } 145 } 146 INTON; 147 } 148 149 struct alias * 150 lookupalias(name, check) 151 char *name; 152 int check; 153 { 154 struct alias *ap = *hashalias(name); 155 156 for (; ap; ap = ap->next) { 157 if (equal(name, ap->name)) { 158 if (check && (ap->flag & ALIASINUSE)) 159 return (NULL); 160 return (ap); 161 } 162 } 163 164 return (NULL); 165 } 166 167 /* 168 * TODO - sort output 169 */ 170 int 171 aliascmd(argc, argv) 172 int argc; 173 char **argv; 174 { 175 char *n, *v; 176 int ret = 0; 177 struct alias *ap; 178 179 if (argc == 1) { 180 int i; 181 182 for (i = 0; i < ATABSIZE; i++) 183 for (ap = atab[i]; ap; ap = ap->next) { 184 if (*ap->name != '\0') 185 out1fmt("alias %s=%s\n", ap->name, ap->val); 186 } 187 return (0); 188 } 189 while ((n = *++argv) != NULL) { 190 if ((v = strchr(n+1, '=')) == NULL) /* n+1: funny ksh stuff */ 191 if ((ap = lookupalias(n, 0)) == NULL) { 192 outfmt(out2, "alias: %s not found\n", n); 193 ret = 1; 194 } else 195 out1fmt("alias %s=%s\n", n, ap->val); 196 else { 197 *v++ = '\0'; 198 setalias(n, v); 199 } 200 } 201 202 return (ret); 203 } 204 205 int 206 unaliascmd(argc, argv) 207 int argc; 208 char **argv; 209 { 210 int i; 211 212 while ((i = nextopt("a")) != '\0') { 213 if (i == 'a') { 214 rmaliases(); 215 return (0); 216 } 217 } 218 for (i = 0; *argptr; argptr++) 219 i = unalias(*argptr); 220 221 return (i); 222 } 223 224 STATIC struct alias ** 225 hashalias(p) 226 register char *p; 227 { 228 unsigned int hashval; 229 230 hashval = *p << 4; 231 while (*p) 232 hashval+= *p++; 233 return &atab[hashval % ATABSIZE]; 234 } 235