Commit | Line | Data |
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b898b9e0 BJ |
1 | /* Copyright (c) 1979 Regents of the University of California */ |
2 | #include "sh.h" | |
3 | ||
4 | /* | |
5 | * C shell | |
6 | */ | |
7 | ||
8 | /* | |
9 | * System level search and execute of a command. | |
10 | * We look in each directory for the specified command name. | |
11 | * If the name contains a '/' then we execute only the full path name. | |
12 | * If there is no search path then we execute only full path names. | |
13 | */ | |
14 | ||
15 | /* | |
16 | * As we search for the command we note the first non-trivial error | |
17 | * message for presentation to the user. This allows us often | |
18 | * to show that a file has the wrong mode/no access when the file | |
19 | * is not in the last component of the search path, so we must | |
20 | * go on after first detecting the error. | |
21 | */ | |
22 | char *exerr; /* Execution error message */ | |
23 | char *expath; /* Path for exerr */ | |
24 | ||
25 | /* | |
26 | * Xhash is an array of HSHSIZ chars, which are used to hash execs. | |
27 | * If it is allocated, then to tell whether ``name'' is (possibly) | |
28 | * present in the i'th component of the variable path, you look at | |
29 | * the i'th bit of xhash[hash("name")]. This is setup automatically | |
30 | * after .login is executed, and recomputed whenever ``path'' is | |
31 | * changed. | |
32 | */ | |
33 | int havhash; | |
34 | #define HSHSIZ 511 | |
35 | char xhash[HSHSIZ]; | |
36 | int hits, misses; | |
37 | ||
38 | /* Dummy search path for just absolute search when no path */ | |
39 | char *justabs[] = { "", 0 }; | |
40 | ||
41 | doexec(t) | |
42 | register struct command *t; | |
43 | { | |
44 | char *sav; | |
45 | register char *dp, **pv, **av; | |
46 | register struct varent *v; | |
47 | bool slash = any('/', t->t_dcom[0]); | |
48 | int hashval, i; | |
49 | char *blk[2]; | |
50 | ||
51 | /* | |
52 | * Glob the command name. If this does anything, then we | |
53 | * will execute the command only relative to ".". One special | |
54 | * case: if there is no PATH, then we execute only commands | |
55 | * which start with '/'. | |
56 | */ | |
57 | dp = globone(t->t_dcom[0]); | |
58 | sav = t->t_dcom[0]; | |
59 | exerr = 0; expath = t->t_dcom[0] = dp; | |
60 | xfree(sav); | |
61 | v = adrof("path"); | |
62 | if (v == 0 && expath[0] != '/') | |
63 | pexerr(); | |
64 | slash |= gflag; | |
65 | ||
66 | /* | |
67 | * Glob the argument list, if necessary. | |
68 | * Otherwise trim off the quote bits. | |
69 | */ | |
70 | gflag = 0; av = &t->t_dcom[1]; | |
71 | rscan(av, tglob); | |
72 | if (gflag) { | |
73 | av = glob(av); | |
74 | if (av == 0) | |
75 | error("No match"); | |
76 | } | |
77 | blk[0] = t->t_dcom[0]; | |
78 | blk[1] = 0; | |
79 | av = blkspl(blk, av); | |
80 | #ifdef VFORK | |
81 | Vav = av; | |
82 | #endif | |
83 | scan(av, trim); | |
84 | ||
85 | xechoit(av); /* Echo command if -x */ | |
86 | closech(); /* Close random fd's */ | |
87 | ||
88 | /* | |
89 | * If no path, no words in path, or a / in the filename | |
90 | * then restrict the command search. | |
91 | */ | |
92 | if (v == 0 || v->vec[0] == 0 || slash) | |
93 | pv = justabs; | |
94 | else | |
95 | pv = v->vec; | |
96 | sav = strspl("/", *av); /* / command name for postpending */ | |
97 | #ifdef VFORK | |
98 | Vsav = sav; | |
99 | #endif | |
100 | if (havhash) | |
101 | hashval = xhash[hash(*av)]; | |
102 | i = 0; | |
103 | hits++; | |
104 | do { | |
105 | if (!slash && pv[0][0] == '/' && havhash && (hashval & (1 << (i % 8))) == 0) | |
106 | goto cont; | |
107 | if (pv[0][0] == 0 || eq(pv[0], ".")) /* don't make ./xxx */ | |
108 | texec(*av, av); | |
109 | else { | |
110 | dp = strspl(*pv, sav); | |
111 | #ifdef VFORK | |
112 | Vdp = dp; | |
113 | #endif | |
114 | texec(dp, av); | |
115 | #ifdef VFORK | |
116 | Vdp = 0; | |
117 | #endif | |
118 | xfree(dp); | |
119 | } | |
120 | misses++; | |
121 | cont: | |
122 | pv++; | |
123 | i++; | |
124 | } while (*pv); | |
125 | hits--; | |
126 | #ifdef VFORK | |
127 | Vsav = 0; | |
128 | Vav = 0; | |
129 | #endif | |
130 | xfree(sav); | |
131 | xfree(av); | |
132 | pexerr(); | |
133 | } | |
134 | ||
135 | pexerr() | |
136 | { | |
137 | ||
138 | /* Couldn't find the damn thing */ | |
139 | setname(expath); | |
140 | /* xfree(expath); */ | |
141 | if (exerr) | |
142 | bferr(exerr); | |
143 | bferr("Command not found"); | |
144 | } | |
145 | ||
146 | /* Last resort shell */ | |
147 | char *lastsh[] = { SHELLPATH, 0 }; | |
148 | ||
149 | /* | |
150 | * Execute command f, arg list t. | |
151 | * Record error message if not found. | |
152 | * Also do shell scripts here. | |
153 | */ | |
154 | texec(f, t) | |
155 | char *f; | |
156 | register char **t; | |
157 | { | |
158 | register struct varent *v; | |
159 | register char **vp; | |
160 | extern char *sys_errlist[]; | |
161 | ||
162 | execv(f, t); | |
163 | switch (errno) { | |
164 | ||
165 | case ENOEXEC: | |
166 | /* | |
167 | * If there is an alias for shell, then | |
168 | * put the words of the alias in front of the | |
169 | * argument list replacing the command name. | |
170 | * Note no interpretation of the words at this point. | |
171 | */ | |
172 | v = adrof1("shell", &aliases); | |
173 | if (v == 0) { | |
174 | #ifdef OTHERSH | |
175 | register int ff = open(f, 0); | |
176 | char ch; | |
177 | #endif | |
178 | ||
179 | vp = lastsh; | |
180 | vp[0] = adrof("shell") ? value("shell") : SHELLPATH; | |
181 | #ifdef OTHERSH | |
182 | if (ff != -1 && read(ff, &ch, 1) == 1 && ch != '#') | |
183 | vp[0] = OTHERSH; | |
184 | close(ff); | |
185 | #endif | |
186 | } else | |
187 | vp = v->vec; | |
188 | t[0] = f; | |
189 | t = blkspl(vp, t); /* Splice up the new arglst */ | |
190 | f = *t; | |
191 | execv(f, t); | |
192 | xfree(t); | |
193 | /* The sky is falling, the sky is falling! */ | |
194 | ||
195 | case ENOMEM: | |
196 | Perror(f); | |
197 | ||
198 | case ENOENT: | |
199 | break; | |
200 | ||
201 | default: | |
202 | if (exerr == 0) { | |
203 | exerr = sys_errlist[errno]; | |
204 | expath = savestr(f); | |
205 | } | |
206 | } | |
207 | } | |
208 | ||
209 | execash(t, kp) | |
210 | register struct command *kp; | |
211 | { | |
212 | ||
213 | didcch++; | |
214 | lshift(kp->t_dcom, 1); | |
215 | doexec(kp); | |
216 | /*NOTREACHED*/ | |
217 | } | |
218 | ||
219 | xechoit(t) | |
220 | char **t; | |
221 | { | |
222 | ||
223 | if (adrof("echo")) { | |
224 | flush(); | |
225 | haderr = 1; | |
226 | blkpr(t), printf("\n"); | |
227 | haderr = 0; | |
228 | } | |
229 | } | |
230 | ||
231 | dohash() | |
232 | { | |
233 | struct stat stb; | |
234 | struct direct dirbuf[BUFSIZ / sizeof (struct direct)]; | |
235 | char d_name[DIRSIZ + 1]; | |
236 | register int dirf, cnt; | |
237 | int i = 0; | |
238 | struct varent *v = adrof("path"); | |
239 | char **pv; | |
240 | ||
241 | havhash = 1; | |
242 | for (cnt = 0; cnt < HSHSIZ; cnt++) | |
243 | xhash[cnt] = 0; | |
244 | if (v == 0) | |
245 | return; | |
246 | for (pv = v->vec; *pv; pv++, i = (i + 1) % 8) { | |
247 | if (pv[0][0] != '/') | |
248 | continue; | |
249 | dirf = open(*pv, 0); | |
250 | if (dirf < 0) | |
251 | continue; | |
252 | if (fstat(dirf, &stb) < 0 || !isdir(stb)) { | |
253 | close(dirf); | |
254 | continue; | |
255 | } | |
256 | while ((cnt = read(dirf, (char *) dirbuf, sizeof dirbuf)) >= sizeof dirbuf[0]) { | |
257 | register struct direct *ep = dirbuf; | |
258 | ||
259 | for (cnt /= sizeof(struct direct); cnt > 0; cnt--, ep++) { | |
260 | if (ep->d_ino == 0) | |
261 | continue; | |
262 | copdent(d_name, ep->d_name); | |
263 | xhash[hash(d_name)] |= (1 << i); | |
264 | } | |
265 | } | |
266 | close(dirf); | |
267 | } | |
268 | } | |
269 | ||
270 | dounhash() | |
271 | { | |
272 | ||
273 | havhash = 0; | |
274 | } | |
275 | ||
276 | hashstat() | |
277 | { | |
278 | ||
279 | if (hits+misses) | |
280 | printf("%d hits, %d misses, %2d%%\n", hits, misses, 100 * hits / (hits + misses)); | |
281 | } | |
282 | ||
283 | hash(cp) | |
284 | register char *cp; | |
285 | { | |
286 | register int hash = 0; | |
287 | ||
288 | while (*cp) | |
289 | hash += hash + *cp++; | |
290 | return (hash % HSHSIZ); | |
291 | } |