Commit | Line | Data |
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31cef89c | 1 | static char *sccsid = "@(#)sh.exec.c 4.1 10/9/80"; |
c5fd306c BJ |
2 | |
3 | #include "sh.h" | |
4 | ||
5 | /* | |
6 | * C shell | |
7 | */ | |
8 | ||
9 | /* | |
10 | * System level search and execute of a command. | |
11 | * We look in each directory for the specified command name. | |
12 | * If the name contains a '/' then we execute only the full path name. | |
13 | * If there is no search path then we execute only full path names. | |
14 | */ | |
15 | ||
16 | /* | |
17 | * As we search for the command we note the first non-trivial error | |
18 | * message for presentation to the user. This allows us often | |
19 | * to show that a file has the wrong mode/no access when the file | |
20 | * is not in the last component of the search path, so we must | |
21 | * go on after first detecting the error. | |
22 | */ | |
23 | char *exerr; /* Execution error message */ | |
24 | char *expath; /* Path for exerr */ | |
25 | ||
26 | /* | |
27 | * Xhash is an array of HSHSIZ chars, which are used to hash execs. | |
28 | * If it is allocated, then to tell whether ``name'' is (possibly) | |
29 | * present in the i'th component of the variable path, you look at | |
30 | * the i'th bit of xhash[hash("name")]. This is setup automatically | |
31 | * after .login is executed, and recomputed whenever ``path'' is | |
32 | * changed. | |
33 | */ | |
34 | int havhash; | |
35 | #define HSHSIZ 511 | |
36 | char xhash[HSHSIZ]; | |
37 | #ifdef VFORK | |
38 | int hits, misses; | |
39 | #endif | |
40 | ||
41 | /* Dummy search path for just absolute search when no path */ | |
42 | char *justabs[] = { "", 0 }; | |
43 | ||
44 | doexec(t) | |
45 | register struct command *t; | |
46 | { | |
47 | char *sav; | |
48 | register char *dp, **pv, **av; | |
49 | register struct varent *v; | |
50 | bool slash = any('/', t->t_dcom[0]); | |
51 | int hashval, i; | |
52 | char *blk[2]; | |
53 | ||
54 | /* | |
55 | * Glob the command name. If this does anything, then we | |
56 | * will execute the command only relative to ".". One special | |
57 | * case: if there is no PATH, then we execute only commands | |
58 | * which start with '/'. | |
59 | */ | |
60 | dp = globone(t->t_dcom[0]); | |
61 | sav = t->t_dcom[0]; | |
62 | exerr = 0; expath = t->t_dcom[0] = dp; | |
63 | xfree(sav); | |
64 | v = adrof("path"); | |
65 | if (v == 0 && expath[0] != '/') | |
66 | pexerr(); | |
67 | slash |= gflag; | |
68 | ||
69 | /* | |
70 | * Glob the argument list, if necessary. | |
71 | * Otherwise trim off the quote bits. | |
72 | */ | |
73 | gflag = 0; av = &t->t_dcom[1]; | |
74 | rscan(av, tglob); | |
75 | if (gflag) { | |
76 | av = glob(av); | |
77 | if (av == 0) | |
78 | error("No match"); | |
79 | } | |
80 | blk[0] = t->t_dcom[0]; | |
81 | blk[1] = 0; | |
82 | av = blkspl(blk, av); | |
83 | #ifdef VFORK | |
84 | Vav = av; | |
85 | #endif | |
86 | scan(av, trim); | |
87 | ||
88 | xechoit(av); /* Echo command if -x */ | |
89 | closech(); /* Close random fd's */ | |
90 | ||
91 | /* | |
92 | * We must do this after any possible forking (like `foo` | |
93 | * in glob) so that this shell can still do subprocesses. | |
94 | */ | |
95 | sigsys(SIGCHLD, SIG_IGN); /* sigsys for vforks sake */ | |
96 | ||
97 | /* | |
98 | * If no path, no words in path, or a / in the filename | |
99 | * then restrict the command search. | |
100 | */ | |
101 | if (v == 0 || v->vec[0] == 0 || slash) | |
102 | pv = justabs; | |
103 | else | |
104 | pv = v->vec; | |
105 | sav = strspl("/", *av); /* / command name for postpending */ | |
106 | #ifdef VFORK | |
107 | Vsav = sav; | |
108 | #endif | |
109 | if (havhash) | |
110 | hashval = xhash[hash(*av)]; | |
111 | i = 0; | |
112 | #ifdef VFORK | |
113 | hits++; | |
114 | #endif | |
115 | do { | |
116 | if (!slash && pv[0][0] == '/' && havhash && (hashval & (1 << (i % 8))) == 0) | |
117 | goto cont; | |
118 | if (pv[0][0] == 0 || eq(pv[0], ".")) /* don't make ./xxx */ | |
119 | texec(*av, av); | |
120 | else { | |
121 | dp = strspl(*pv, sav); | |
122 | #ifdef VFORK | |
123 | Vdp = dp; | |
124 | #endif | |
125 | texec(dp, av); | |
126 | #ifdef VFORK | |
127 | Vdp = 0; | |
128 | #endif | |
129 | xfree(dp); | |
130 | } | |
131 | #ifdef VFORK | |
132 | misses++; | |
133 | #endif | |
134 | cont: | |
135 | pv++; | |
136 | i++; | |
137 | } while (*pv); | |
138 | #ifdef VFORK | |
139 | hits--; | |
140 | #endif | |
141 | #ifdef VFORK | |
142 | Vsav = 0; | |
143 | Vav = 0; | |
144 | #endif | |
145 | xfree(sav); | |
146 | xfree(av); | |
147 | pexerr(); | |
148 | } | |
149 | ||
150 | pexerr() | |
151 | { | |
152 | ||
153 | /* Couldn't find the damn thing */ | |
154 | setname(expath); | |
155 | /* xfree(expath); */ | |
156 | if (exerr) | |
157 | bferr(exerr); | |
158 | bferr("Command not found"); | |
159 | } | |
160 | ||
161 | /* Last resort shell */ | |
162 | char *lastsh[] = { SHELLPATH, 0 }; | |
163 | ||
164 | /* | |
165 | * Execute command f, arg list t. | |
166 | * Record error message if not found. | |
167 | * Also do shell scripts here. | |
168 | */ | |
169 | texec(f, t) | |
170 | char *f; | |
171 | register char **t; | |
172 | { | |
173 | register struct varent *v; | |
174 | register char **vp; | |
175 | extern char *sys_errlist[]; | |
176 | ||
177 | execv(f, t); | |
178 | switch (errno) { | |
179 | ||
180 | case ENOEXEC: | |
181 | /* | |
182 | * If there is an alias for shell, then | |
183 | * put the words of the alias in front of the | |
184 | * argument list replacing the command name. | |
185 | * Note no interpretation of the words at this point. | |
186 | */ | |
187 | v = adrof1("shell", &aliases); | |
188 | if (v == 0) { | |
189 | #ifdef OTHERSH | |
190 | register int ff = open(f, 0); | |
191 | char ch; | |
192 | #endif | |
193 | ||
194 | vp = lastsh; | |
195 | vp[0] = adrof("shell") ? value("shell") : SHELLPATH; | |
196 | #ifdef OTHERSH | |
197 | if (ff != -1 && read(ff, &ch, 1) == 1 && ch != '#') | |
198 | vp[0] = OTHERSH; | |
199 | close(ff); | |
200 | #endif | |
201 | } else | |
202 | vp = v->vec; | |
203 | t[0] = f; | |
204 | t = blkspl(vp, t); /* Splice up the new arglst */ | |
205 | f = *t; | |
206 | execv(f, t); | |
207 | xfree((char *)t); | |
208 | /* The sky is falling, the sky is falling! */ | |
209 | ||
210 | case ENOMEM: | |
211 | Perror(f); | |
212 | ||
213 | case ENOENT: | |
214 | break; | |
215 | ||
216 | default: | |
217 | if (exerr == 0) { | |
218 | exerr = sys_errlist[errno]; | |
219 | expath = savestr(f); | |
220 | } | |
221 | } | |
222 | } | |
223 | ||
224 | execash(t, kp) | |
225 | register struct command *kp; | |
226 | { | |
227 | ||
228 | didcch++; | |
229 | signal(SIGINT, parintr); | |
230 | signal(SIGQUIT, parintr); | |
231 | signal(SIGTERM, parterm); /* if doexec loses, screw */ | |
232 | lshift(kp->t_dcom, 1); | |
233 | exiterr++; | |
234 | doexec(kp); | |
235 | /*NOTREACHED*/ | |
236 | } | |
237 | ||
238 | xechoit(t) | |
239 | char **t; | |
240 | { | |
241 | ||
242 | if (adrof("echo")) { | |
243 | flush(); | |
244 | haderr = 1; | |
245 | blkpr(t), printf("\n"); | |
246 | haderr = 0; | |
247 | } | |
248 | } | |
249 | ||
250 | dohash() | |
251 | { | |
252 | struct stat stb; | |
253 | struct direct dirbuf[BUFSIZ / sizeof (struct direct)]; | |
254 | char d_name[DIRSIZ + 1]; | |
255 | register int dirf, cnt; | |
256 | int i = 0; | |
257 | struct varent *v = adrof("path"); | |
258 | char **pv; | |
259 | ||
260 | havhash = 1; | |
261 | for (cnt = 0; cnt < HSHSIZ; cnt++) | |
262 | xhash[cnt] = 0; | |
263 | if (v == 0) | |
264 | return; | |
265 | for (pv = v->vec; *pv; pv++, i = (i + 1) % 8) { | |
266 | if (pv[0][0] != '/') | |
267 | continue; | |
268 | dirf = open(*pv, 0); | |
269 | if (dirf < 0) | |
270 | continue; | |
271 | if (fstat(dirf, &stb) < 0 || !isdir(stb)) { | |
272 | close(dirf); | |
273 | continue; | |
274 | } | |
275 | while ((cnt = read(dirf, (char *) dirbuf, sizeof dirbuf)) >= sizeof dirbuf[0]) { | |
276 | register struct direct *ep = dirbuf; | |
277 | ||
278 | for (cnt /= sizeof(struct direct); cnt > 0; cnt--, ep++) { | |
279 | if (ep->d_ino == 0) | |
280 | continue; | |
281 | copdent(d_name, ep->d_name); | |
282 | xhash[hash(d_name)] |= (1 << i); | |
283 | } | |
284 | } | |
285 | close(dirf); | |
286 | } | |
287 | } | |
288 | ||
289 | dounhash() | |
290 | { | |
291 | ||
292 | havhash = 0; | |
293 | } | |
294 | ||
295 | #ifdef VFORK | |
296 | hashstat() | |
297 | { | |
298 | ||
299 | if (hits+misses) | |
300 | printf("%d hits, %d misses, %2d%%\n", hits, misses, 100 * hits / (hits + misses)); | |
301 | } | |
302 | #endif | |
303 | ||
304 | hash(cp) | |
305 | register char *cp; | |
306 | { | |
307 | register long hash = 0; | |
308 | int retval; | |
309 | ||
310 | while (*cp) | |
311 | hash += hash + *cp++; | |
312 | if (hash < 0) | |
313 | hash = -hash; | |
314 | retval = hash % HSHSIZ; | |
315 | return (retval); | |
316 | } |