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36 * @(#)alias.c 8.3 (Berkeley) 5/4/95
37 * $FreeBSD: src/bin/sh/alias.c,v 1.32 2011/06/13 21:03:27 jilles Exp $
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)) {
70 ap->val = savestr(val);
77 ap = ckmalloc(sizeof (struct alias));
78 ap->name = savestr(name);
80 * XXX - HACK: in order that the parser will not finish reading the
81 * alias value off the input before processing the next alias, we
82 * dummy up an extra space at the end of the alias. This is a crock
83 * and should be re-thought. The idea (if you feel inclined to help)
84 * is to avoid alias recursions. The mechanism used is: when
85 * expanding an alias, the value of the alias is pushed back on the
86 * input as a string and a pointer to the alias is stored with the
87 * string. The alias is marked as being in use. When the input
88 * routine finishes reading the string, it marks the alias not
89 * in use. The problem is synchronization with the parser. Since
90 * it reads ahead, the alias is marked not in use before the
91 * resulting token(s) is next checked for further alias sub. The
92 * H A C K is that we add a little fluff after the alias value
93 * so that the string will not be exhausted. This is a good
94 * idea ------- ***NOT***
97 ap->val = savestr(val);
100 size_t len = strlen(val);
101 ap->val = ckmalloc(len + 2);
102 memcpy(ap->val, val, len);
103 ap->val[len] = ' '; /* fluff */
104 ap->val[len+1] = '\0';
115 unalias(const char *name)
117 struct alias *ap, **app;
119 app = hashalias(name);
121 for (ap = *app; ap; app = &(ap->next), ap = ap->next) {
122 if (equal(name, ap->name)) {
124 * if the alias is currently in use (i.e. its
125 * buffer is being used by the input routine) we
126 * just null out the name instead of freeing it.
127 * We could clear it out later, but this situation
128 * is so rare that it hardly seems worth it.
130 if (ap->flag & ALIASINUSE)
151 struct alias *ap, *tmp;
155 for (i = 0; i < ATABSIZE; i++) {
171 lookupalias(const char *name, int check)
173 struct alias *ap = *hashalias(name);
175 for (; ap; ap = ap->next) {
176 if (equal(name, ap->name)) {
177 if (check && (ap->flag & ALIASINUSE))
187 comparealiases(const void *p1, const void *p2)
189 const struct alias *const *a1 = p1;
190 const struct alias *const *a2 = p2;
192 return strcmp((*a1)->name, (*a2)->name);
196 printalias(const struct alias *a)
200 out1fmt("%s=", a->name);
201 /* Don't print the space added above. */
202 p = a->val + strlen(a->val) - 1;
213 struct alias **sorted, *ap;
215 sorted = ckmalloc(aliases * sizeof(*sorted));
217 for (i = 0; i < ATABSIZE; i++)
218 for (ap = atab[i]; ap; ap = ap->next)
219 if (*ap->name != '\0')
221 qsort(sorted, aliases, sizeof(*sorted), comparealiases);
222 for (i = 0; i < aliases; i++)
223 printalias(sorted[i]);
228 aliascmd(int argc, char **argv)
238 while ((n = *++argv) != NULL) {
239 if ((v = strchr(n+1, '=')) == NULL) /* n+1: funny ksh stuff */
240 if ((ap = lookupalias(n, 0)) == NULL) {
241 warning("%s: not found", n);
255 unaliascmd(int argc __unused, char **argv __unused)
259 while ((i = nextopt("a")) != '\0') {
265 for (i = 0; *argptr; argptr++)
266 i |= unalias(*argptr);
271 static struct alias **
272 hashalias(const char *p)
274 unsigned int hashval;
279 return &atab[hashval % ATABSIZE];