1 /* Toybox infrastructure.
2 *
3 * Copyright 2006 Rob Landley <rob@landley.net>
4 */
5
6 #include "toys.h"
7
8 #ifndef TOYBOX_VERSION
9 #define TOYBOX_VERSION "0.7.3"
10 #endif
11
12 // Populate toy_list[].
13
14 #undef NEWTOY
15 #undef OLDTOY
16 #define NEWTOY(name, opts, flags) {#name, name##_main, OPTSTR_##name, flags},
17 #define OLDTOY(name, oldname, flags) \
18 {#name, oldname##_main, OPTSTR_##oldname, flags},
19
20 struct toy_list toy_list[] = {
21 #include "generated/newtoys.h"
22 };
23
24 // global context for this command.
25
26 struct toy_context toys;
27 union global_union this;
28 char toybuf[4096], libbuf[4096];
29
toy_find(char * name)30 struct toy_list *toy_find(char *name)
31 {
32 int top, bottom, middle;
33
34 if (!CFG_TOYBOX) return 0;
35
36 // If the name starts with "toybox" accept that as a match. Otherwise
37 // skip the first entry, which is out of order.
38
39 if (!strncmp(name,"toybox",6)) return toy_list;
40 bottom = 1;
41
42 // Binary search to find this command.
43
44 top = ARRAY_LEN(toy_list)-1;
45 for (;;) {
46 int result;
47
48 middle = (top+bottom)/2;
49 if (middle<bottom || middle>top) return NULL;
50 result = strcmp(name,toy_list[middle].name);
51 if (!result) return toy_list+middle;
52 if (result<0) top=--middle;
53 else bottom = ++middle;
54 }
55 }
56
57 // Figure out whether or not anything is using the option parsing logic,
58 // because the compiler can't figure out whether or not to optimize it away
59 // on its' own. NEED_OPTIONS becomes a constant allowing if() to optimize
60 // stuff out via dead code elimination.
61
62 #undef NEWTOY
63 #undef OLDTOY
64 #define NEWTOY(name, opts, flags) opts ||
65 #define OLDTOY(name, oldname, flags) OPTSTR_##oldname ||
66 static const int NEED_OPTIONS =
67 #include "generated/newtoys.h"
68 0; // Ends the opts || opts || opts...
69
unknown(char * name)70 static void unknown(char *name)
71 {
72 toys.exitval = 127;
73 toys.which = toy_list;
74 error_exit("Unknown command %s", name);
75 }
76
77 // Setup toybox global state for this command.
toy_singleinit(struct toy_list * which,char * argv[])78 static void toy_singleinit(struct toy_list *which, char *argv[])
79 {
80 toys.which = which;
81 toys.argv = argv;
82
83 if (CFG_TOYBOX_I18N) setlocale(LC_ALL, "C"+!!(which->flags & TOYFLAG_LOCALE));
84
85 // Parse --help and --version for (almost) all commands
86 if (CFG_TOYBOX_HELP_DASHDASH && !(which->flags & TOYFLAG_NOHELP) && argv[1]) {
87 if (!strcmp(argv[1], "--help")) {
88 if (CFG_TOYBOX && toys.which == toy_list && toys.argv[2])
89 if (!(toys.which = toy_find(toys.argv[2]))) unknown(toys.argv[2]);
90 show_help(stdout);
91 xexit();
92 }
93
94 if (!strcmp(argv[1], "--version")) {
95 xputs("toybox "TOYBOX_VERSION);
96 xexit();
97 }
98 }
99
100 if (NEED_OPTIONS && which->options) get_optflags();
101 else {
102 toys.optargs = argv+1;
103 for (toys.optc = 0; toys.optargs[toys.optc]; toys.optc++);
104 }
105 toys.old_umask = umask(0);
106 if (!(which->flags & TOYFLAG_UMASK)) umask(toys.old_umask);
107 toys.signalfd--;
108 toys.toycount = ARRAY_LEN(toy_list);
109 }
110
111 // Full init needed by multiplexer or reentrant calls, calls singleinit at end
toy_init(struct toy_list * which,char * argv[])112 void toy_init(struct toy_list *which, char *argv[])
113 {
114 void *oldwhich = toys.which;
115
116 // Drop permissions for non-suid commands.
117
118 if (CFG_TOYBOX_SUID) {
119 if (!toys.which) toys.which = toy_list;
120
121 uid_t uid = getuid(), euid = geteuid();
122
123 if (!(which->flags & TOYFLAG_STAYROOT)) {
124 if (uid != euid) {
125 if (setuid(uid)) perror_exit("setuid %d->%d", euid, uid); // drop root
126 euid = uid;
127 toys.wasroot++;
128 }
129 } else if (CFG_TOYBOX_DEBUG && uid && which != toy_list)
130 error_msg("Not installed suid root");
131
132 if ((which->flags & TOYFLAG_NEEDROOT) && euid) help_exit("Not root");
133 }
134
135 // Free old toys contents (to be reentrant), but leave rebound if any
136 // don't blank old optargs if our new argc lives in the old optargs.
137 if (argv<toys.optargs || argv>toys.optargs+toys.optc) free(toys.optargs);
138 memset(&toys, 0, offsetof(struct toy_context, rebound));
139 if (oldwhich) memset(&this, 0, sizeof(this));
140
141 // Continue to portion of init needed by standalone commands
142 toy_singleinit(which, argv);
143 }
144
145 // Like exec() but runs an internal toybox command instead of another file.
146 // Only returns if it can't run command internally, otherwise exit() when done.
toy_exec(char * argv[])147 void toy_exec(char *argv[])
148 {
149 struct toy_list *which;
150
151 // Return if we can't find it (which includes no multiplexer case),
152 if (!(which = toy_find(*argv))) return;
153
154 // Return if stack depth getting noticeable (proxy for leaked heap, etc).
155
156 // Compiler writers have decided subtracting char * is undefined behavior,
157 // so convert to integers. (LP64 says sizeof(long)==sizeof(pointer).)
158 if (!CFG_TOYBOX_NORECURSE)
159 if (toys.stacktop && labs((long)toys.stacktop-(long)&which)>6000) return;
160
161 // Return if we need to re-exec to acquire root via suid bit.
162 if (toys.which && (which->flags&TOYFLAG_ROOTONLY) && toys.wasroot) return;
163
164 // Run command
165 toy_init(which, argv);
166 if (toys.which) toys.which->toy_main();
167 xexit();
168 }
169
170 // Multiplexer command, first argument is command to run, rest are args to that.
171 // If first argument starts with - output list of command install paths.
toybox_main(void)172 void toybox_main(void)
173 {
174 static char *toy_paths[]={"usr/","bin/","sbin/",0};
175 int i, len = 0;
176
177 // fast path: try to exec immediately.
178 // (Leave toys.which null to disable suid return logic.)
179 if (toys.argv[1]) toy_exec(toys.argv+1);
180
181 // For early error reporting
182 toys.which = toy_list;
183
184 if (toys.argv[1] && toys.argv[1][0] != '-') unknown(toys.argv[1]);
185
186 // Output list of command.
187 for (i=1; i<ARRAY_LEN(toy_list); i++) {
188 int fl = toy_list[i].flags;
189 if (fl & TOYMASK_LOCATION) {
190 if (toys.argv[1]) {
191 int j;
192 for (j=0; toy_paths[j]; j++)
193 if (fl & (1<<j)) len += printf("%s", toy_paths[j]);
194 }
195 len += printf("%s",toy_list[i].name);
196 if (++len > 65) len = 0;
197 xputc(len ? ' ' : '\n');
198 }
199 }
200 xputc('\n');
201 }
202
main(int argc,char * argv[])203 int main(int argc, char *argv[])
204 {
205 if (!*argv) return 127;
206
207 // Snapshot stack location so we can detect recursion depth later.
208 // This is its own block so probe doesn't permanently consume stack.
209 else {
210 int stack;
211
212 toys.stacktop = &stack;
213 }
214 *argv = getbasename(*argv);
215
216 // Up to and including Android M, bionic's dynamic linker added a handler to
217 // cause a crash dump on SIGPIPE. That was removed in Android N, but adbd
218 // was still setting the SIGPIPE disposition to SIG_IGN, and its children
219 // were inheriting that. In Android O, adbd is fixed, but manually asking
220 // for the default disposition is harmless, and it'll be a long time before
221 // no one's using anything older than O!
222 if (CFG_TOYBOX_ON_ANDROID) signal(SIGPIPE, SIG_DFL);
223
224 // If nommu can't fork, special reentry path.
225 // Use !stacktop to signal "vfork happened", both before and after xexec()
226 if (!CFG_TOYBOX_FORK) {
227 if (0x80 & **argv) {
228 **argv &= 0x7f;
229 toys.stacktop = 0;
230 }
231 }
232
233 if (CFG_TOYBOX) {
234 // Call the multiplexer, adjusting this argv[] to be its' argv[1].
235 // (It will adjust it back before calling toy_exec().)
236 toys.argv = argv-1;
237 toybox_main();
238 } else {
239 // a single toybox command built standalone with no multiplexer
240 toy_singleinit(toy_list, argv);
241 toy_list->toy_main();
242 }
243
244 xexit();
245 }
246