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36 * @(#)alias.c 8.3 (Berkeley) 5/4/95
37 * $FreeBSD: head/bin/sh/alias.c 242766 2012-11-08 13:33:48Z jilles $
47 #include "options.h" /* XXX for argptr (should remove?) */
52 static struct alias *atab[ATABSIZE];
55 static void setalias(const char *, const char *);
56 static int unalias(const char *);
57 static struct alias **hashalias(const char *);
61 setalias(const char *name, const char *val)
63 struct alias *ap, **app;
65 app = hashalias(name);
66 for (ap = *app; ap; ap = ap->next) {
67 if (equal(name, ap->name)) {
72 ap->val = savestr(val);
75 size_t len = strlen(val);
76 ap->val = ckmalloc(len + 2);
77 memcpy(ap->val, val, len);
79 ap->val[len+1] = '\0';
88 ap = ckmalloc(sizeof (struct alias));
89 ap->name = savestr(name);
91 * XXX - HACK: in order that the parser will not finish reading the
92 * alias value off the input before processing the next alias, we
93 * dummy up an extra space at the end of the alias. This is a crock
94 * and should be re-thought. The idea (if you feel inclined to help)
95 * is to avoid alias recursions. The mechanism used is: when
96 * expanding an alias, the value of the alias is pushed back on the
97 * input as a string and a pointer to the alias is stored with the
98 * string. The alias is marked as being in use. When the input
99 * routine finishes reading the string, it marks the alias not
100 * in use. The problem is synchronization with the parser. Since
101 * it reads ahead, the alias is marked not in use before the
102 * resulting token(s) is next checked for further alias sub. The
103 * H A C K is that we add a little fluff after the alias value
104 * so that the string will not be exhausted. This is a good
105 * idea ------- ***NOT***
108 ap->val = savestr(val);
111 size_t len = strlen(val);
112 ap->val = ckmalloc(len + 2);
113 memcpy(ap->val, val, len);
114 ap->val[len] = ' '; /* fluff */
115 ap->val[len+1] = '\0';
126 unalias(const char *name)
128 struct alias *ap, **app;
130 app = hashalias(name);
132 for (ap = *app; ap; app = &(ap->next), ap = ap->next) {
133 if (equal(name, ap->name)) {
135 * if the alias is currently in use (i.e. its
136 * buffer is being used by the input routine) we
137 * just null out the name instead of freeing it.
138 * We could clear it out later, but this situation
139 * is so rare that it hardly seems worth it.
141 if (ap->flag & ALIASINUSE)
162 struct alias *ap, *tmp;
166 for (i = 0; i < ATABSIZE; i++) {
182 lookupalias(const char *name, int check)
184 struct alias *ap = *hashalias(name);
186 for (; ap; ap = ap->next) {
187 if (equal(name, ap->name)) {
188 if (check && (ap->flag & ALIASINUSE))
198 comparealiases(const void *p1, const void *p2)
200 const struct alias *const *a1 = p1;
201 const struct alias *const *a2 = p2;
203 return strcmp((*a1)->name, (*a2)->name);
207 printalias(const struct alias *a)
211 out1fmt("%s=", a->name);
212 /* Don't print the space added above. */
213 p = a->val + strlen(a->val) - 1;
224 struct alias **sorted, *ap;
226 sorted = ckmalloc(aliases * sizeof(*sorted));
228 for (i = 0; i < ATABSIZE; i++)
229 for (ap = atab[i]; ap; ap = ap->next)
230 if (*ap->name != '\0')
232 qsort(sorted, aliases, sizeof(*sorted), comparealiases);
233 for (i = 0; i < aliases; i++)
234 printalias(sorted[i]);
239 aliascmd(int argc, char **argv)
249 while ((n = *++argv) != NULL) {
250 if ((v = strchr(n+1, '=')) == NULL) /* n+1: funny ksh stuff */
251 if ((ap = lookupalias(n, 0)) == NULL) {
252 warning("%s: not found", n);
266 unaliascmd(int argc __unused, char **argv __unused)
270 while ((i = nextopt("a")) != '\0') {
276 for (i = 0; *argptr; argptr++)
277 i |= unalias(*argptr);
282 static struct alias **
283 hashalias(const char *p)
285 unsigned int hashval;
290 return &atab[hashval % ATABSIZE];