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36 * @(#)alias.c 8.3 (Berkeley) 5/4/95
37 * $FreeBSD: src/bin/sh/alias.c,v 1.31 2011/06/04 15:05:52 jilles Exp $
47 #include "options.h" /* XXX for argptr (should remove?) */
51 static struct alias *atab[ATABSIZE];
54 static void setalias(const char *, const char *);
55 static int unalias(const char *);
56 static struct alias **hashalias(const char *);
60 setalias(const char *name, const char *val)
62 struct alias *ap, **app;
64 app = hashalias(name);
65 for (ap = *app; ap; ap = ap->next) {
66 if (equal(name, ap->name)) {
69 ap->val = savestr(val);
76 ap = ckmalloc(sizeof (struct alias));
77 ap->name = savestr(name);
79 * XXX - HACK: in order that the parser will not finish reading the
80 * alias value off the input before processing the next alias, we
81 * dummy up an extra space at the end of the alias. This is a crock
82 * and should be re-thought. The idea (if you feel inclined to help)
83 * is to avoid alias recursions. The mechanism used is: when
84 * expanding an alias, the value of the alias is pushed back on the
85 * input as a string and a pointer to the alias is stored with the
86 * string. The alias is marked as being in use. When the input
87 * routine finishes reading the string, it marks the alias not
88 * in use. The problem is synchronization with the parser. Since
89 * it reads ahead, the alias is marked not in use before the
90 * resulting token(s) is next checked for further alias sub. The
91 * H A C K is that we add a little fluff after the alias value
92 * so that the string will not be exhausted. This is a good
93 * idea ------- ***NOT***
96 ap->val = savestr(val);
99 size_t len = strlen(val);
100 ap->val = ckmalloc(len + 2);
101 memcpy(ap->val, val, len);
102 ap->val[len] = ' '; /* fluff */
103 ap->val[len+1] = '\0';
114 unalias(const char *name)
116 struct alias *ap, **app;
118 app = hashalias(name);
120 for (ap = *app; ap; app = &(ap->next), ap = ap->next) {
121 if (equal(name, ap->name)) {
123 * if the alias is currently in use (i.e. its
124 * buffer is being used by the input routine) we
125 * just null out the name instead of freeing it.
126 * We could clear it out later, but this situation
127 * is so rare that it hardly seems worth it.
129 if (ap->flag & ALIASINUSE)
150 struct alias *ap, *tmp;
154 for (i = 0; i < ATABSIZE; i++) {
170 lookupalias(const char *name, int check)
172 struct alias *ap = *hashalias(name);
174 for (; ap; ap = ap->next) {
175 if (equal(name, ap->name)) {
176 if (check && (ap->flag & ALIASINUSE))
186 comparealiases(const void *p1, const void *p2)
188 const struct alias *const *a1 = p1;
189 const struct alias *const *a2 = p2;
191 return strcmp((*a1)->name, (*a2)->name);
195 printalias(const struct alias *a)
199 out1fmt("%s=", a->name);
200 /* Don't print the space added above. */
201 p = a->val + strlen(a->val) - 1;
212 struct alias **sorted, *ap;
214 sorted = ckmalloc(aliases * sizeof(*sorted));
216 for (i = 0; i < ATABSIZE; i++)
217 for (ap = atab[i]; ap; ap = ap->next)
218 if (*ap->name != '\0')
220 qsort(sorted, aliases, sizeof(*sorted), comparealiases);
221 for (i = 0; i < aliases; i++)
222 printalias(sorted[i]);
227 aliascmd(int argc, char **argv)
237 while ((n = *++argv) != NULL) {
238 if ((v = strchr(n+1, '=')) == NULL) /* n+1: funny ksh stuff */
239 if ((ap = lookupalias(n, 0)) == NULL) {
240 warning("%s: not found", n);
254 unaliascmd(int argc __unused, char **argv __unused)
258 while ((i = nextopt("a")) != '\0') {
264 for (i = 0; *argptr; argptr++)
265 i |= unalias(*argptr);
270 static struct alias **
271 hashalias(const char *p)
273 unsigned int hashval;
278 return &atab[hashval % ATABSIZE];