1 /* Toybox infrastructure.
2 *
3 * Copyright 2006 Rob Landley <rob@landley.net>
4 */
5
6 #include "toys.h"
7
8 #ifndef TOYBOX_VERSION
9 #ifndef TOYBOX_VENDOR
10 #define TOYBOX_VENDOR ""
11 #endif
12 #define TOYBOX_VERSION "0.8.0"TOYBOX_VENDOR
13 #endif
14
15 // Populate toy_list[].
16
17 #undef NEWTOY
18 #undef OLDTOY
19 #define NEWTOY(name, opts, flags) {#name, name##_main, OPTSTR_##name, flags},
20 #define OLDTOY(name, oldname, flags) \
21 {#name, oldname##_main, OPTSTR_##oldname, flags},
22
23 struct toy_list toy_list[] = {
24 #include "generated/newtoys.h"
25 };
26
27 // global context for this command.
28
29 struct toy_context toys;
30 union global_union this;
31 char toybuf[4096], libbuf[4096];
32
toy_find(char * name)33 struct toy_list *toy_find(char *name)
34 {
35 int top, bottom, middle;
36
37 if (!CFG_TOYBOX || strchr(name, '/')) return 0;
38
39 // If the name starts with "toybox" accept that as a match. Otherwise
40 // skip the first entry, which is out of order.
41
42 if (!strncmp(name,"toybox",6)) return toy_list;
43 bottom = 1;
44
45 // Binary search to find this command.
46
47 top = ARRAY_LEN(toy_list)-1;
48 for (;;) {
49 int result;
50
51 middle = (top+bottom)/2;
52 if (middle<bottom || middle>top) return NULL;
53 result = strcmp(name,toy_list[middle].name);
54 if (!result) return toy_list+middle;
55 if (result<0) top = --middle;
56 else bottom = ++middle;
57 }
58 }
59
60 // Figure out whether or not anything is using the option parsing logic,
61 // because the compiler can't figure out whether or not to optimize it away
62 // on its' own. NEED_OPTIONS becomes a constant allowing if() to optimize
63 // stuff out via dead code elimination.
64
65 #undef NEWTOY
66 #undef OLDTOY
67 #define NEWTOY(name, opts, flags) opts ||
68 #define OLDTOY(name, oldname, flags) OPTSTR_##oldname ||
69 static const int NEED_OPTIONS =
70 #include "generated/newtoys.h"
71 0; // Ends the opts || opts || opts...
72
unknown(char * name)73 static void unknown(char *name)
74 {
75 toys.exitval = 127;
76 toys.which = toy_list;
77 error_exit("Unknown command %s", name);
78 }
79
80 // Setup toybox global state for this command.
toy_singleinit(struct toy_list * which,char * argv[])81 static void toy_singleinit(struct toy_list *which, char *argv[])
82 {
83 toys.which = which;
84 toys.argv = argv;
85
86 if (CFG_TOYBOX_I18N) setlocale(LC_CTYPE, "C.UTF-8");
87
88 // Parse --help and --version for (almost) all commands
89 if (CFG_TOYBOX_HELP_DASHDASH && !(which->flags & TOYFLAG_NOHELP) && argv[1]) {
90 if (!strcmp(argv[1], "--help")) {
91 if (CFG_TOYBOX && toys.which == toy_list && toys.argv[2])
92 if (!(toys.which = toy_find(toys.argv[2]))) unknown(toys.argv[2]);
93 show_help(stdout);
94 xexit();
95 }
96
97 if (!strcmp(argv[1], "--version")) {
98 xputs("toybox "TOYBOX_VERSION);
99 xexit();
100 }
101 }
102
103 if (NEED_OPTIONS && which->options) get_optflags();
104 else {
105 toys.optargs = argv+1;
106 for (toys.optc = 0; toys.optargs[toys.optc]; toys.optc++);
107 }
108 toys.old_umask = umask(0);
109 if (!(which->flags & TOYFLAG_UMASK)) umask(toys.old_umask);
110 toys.signalfd--;
111 toys.toycount = ARRAY_LEN(toy_list);
112 }
113
114 // Full init needed by multiplexer or reentrant calls, calls singleinit at end
toy_init(struct toy_list * which,char * argv[])115 void toy_init(struct toy_list *which, char *argv[])
116 {
117 void *oldwhich = toys.which;
118
119 // Drop permissions for non-suid commands.
120
121 if (CFG_TOYBOX_SUID) {
122 if (!toys.which) toys.which = toy_list;
123
124 uid_t uid = getuid(), euid = geteuid();
125
126 if (!(which->flags & TOYFLAG_STAYROOT)) {
127 if (uid != euid) {
128 if (setuid(uid)) perror_exit("setuid %d->%d", euid, uid); // drop root
129 euid = uid;
130 toys.wasroot++;
131 }
132 } else if (CFG_TOYBOX_DEBUG && uid && which != toy_list)
133 error_msg("Not installed suid root");
134
135 if ((which->flags & TOYFLAG_NEEDROOT) && euid) help_exit("Not root");
136 }
137
138 // Free old toys contents (to be reentrant), but leave rebound if any
139 // don't blank old optargs if our new argc lives in the old optargs.
140 if (argv<toys.optargs || argv>toys.optargs+toys.optc) free(toys.optargs);
141 memset(&toys, 0, offsetof(struct toy_context, rebound));
142 if (oldwhich) memset(&this, 0, sizeof(this));
143
144 // Continue to portion of init needed by standalone commands
145 toy_singleinit(which, argv);
146 }
147
148 // Run an internal toybox command.
149 // Only returns if it can't run command internally, otherwise xexit() when done.
toy_exec_which(struct toy_list * which,char * argv[])150 void toy_exec_which(struct toy_list *which, char *argv[])
151 {
152 // Return if we can't find it (which includes no multiplexer case),
153 if (!which) return;
154
155 // Return if stack depth getting noticeable (proxy for leaked heap, etc).
156
157 // Compiler writers have decided subtracting char * is undefined behavior,
158 // so convert to integers. (LP64 says sizeof(long)==sizeof(pointer).)
159 // Signed typecast so stack growth direction is irrelevant: we're measuring
160 // the distance between two pointers on the same stack, hence the labs().
161 if (!CFG_TOYBOX_NORECURSE && toys.stacktop)
162 if (labs((long)toys.stacktop-(long)&which)>6000) return;
163
164 // Return if we need to re-exec to acquire root via suid bit.
165 if (toys.which && (which->flags&TOYFLAG_ROOTONLY) && toys.wasroot) return;
166
167 // Run command
168 toy_init(which, argv);
169 if (toys.which) toys.which->toy_main();
170 xexit();
171 }
172
173 // Lookup internal toybox command to run via argv[0]
toy_exec(char * argv[])174 void toy_exec(char *argv[])
175 {
176 toy_exec_which(toy_find(basename(*argv)), argv);
177 }
178
179 // Multiplexer command, first argument is command to run, rest are args to that.
180 // If first argument starts with - output list of command install paths.
toybox_main(void)181 void toybox_main(void)
182 {
183 static char *toy_paths[]={"usr/","bin/","sbin/",0};
184 int i, len = 0;
185
186 // fast path: try to exec immediately.
187 // (Leave toys.which null to disable suid return logic.)
188 // Try dereferencing one layer of symlink
189 if (toys.argv[1]) {
190 toy_exec(toys.argv+1);
191 if (0<readlink(toys.argv[1], libbuf, sizeof(libbuf)))
192 toy_exec_which(toy_find(basename(libbuf)), toys.argv);
193 }
194
195 // For early error reporting
196 toys.which = toy_list;
197
198 if (toys.argv[1] && toys.argv[1][0] != '-') unknown(toys.argv[1]);
199
200 // Output list of command.
201 for (i=1; i<ARRAY_LEN(toy_list); i++) {
202 int fl = toy_list[i].flags;
203 if (fl & TOYMASK_LOCATION) {
204 if (toys.argv[1]) {
205 int j;
206 for (j=0; toy_paths[j]; j++)
207 if (fl & (1<<j)) len += printf("%s", toy_paths[j]);
208 }
209 len += printf("%s",toy_list[i].name);
210 if (++len > 65) len = 0;
211 xputc(len ? ' ' : '\n');
212 }
213 }
214 xputc('\n');
215 }
216
main(int argc,char * argv[])217 int main(int argc, char *argv[])
218 {
219 if (!*argv) return 127;
220
221 // Snapshot stack location so we can detect recursion depth later.
222 // This is its own block so probe doesn't permanently consume stack.
223 else {
224 int stack;
225
226 toys.stacktop = &stack;
227 }
228
229 // Up to and including Android M, bionic's dynamic linker added a handler to
230 // cause a crash dump on SIGPIPE. That was removed in Android N, but adbd
231 // was still setting the SIGPIPE disposition to SIG_IGN, and its children
232 // were inheriting that. In Android O, adbd is fixed, but manually asking
233 // for the default disposition is harmless, and it'll be a long time before
234 // no one's using anything older than O!
235 if (CFG_TOYBOX_ON_ANDROID) signal(SIGPIPE, SIG_DFL);
236
237 // If nommu can't fork, special reentry path.
238 // Use !stacktop to signal "vfork happened", both before and after xexec()
239 if (!CFG_TOYBOX_FORK) {
240 if (0x80 & **argv) {
241 **argv &= 0x7f;
242 toys.stacktop = 0;
243 }
244 }
245
246 if (CFG_TOYBOX) {
247 // Call the multiplexer, adjusting this argv[] to be its' argv[1].
248 // (It will adjust it back before calling toy_exec().)
249 toys.argv = argv-1;
250 toybox_main();
251 } else {
252 // a single toybox command built standalone with no multiplexer
253 toy_singleinit(toy_list, argv);
254 toy_list->toy_main();
255 }
256
257 xexit();
258 }
259