1 /* Toybox infrastructure.
2  *
3  * Copyright 2006 Rob Landley <rob@landley.net>
4  */
5 
6 #include "toys.h"
7 
8 // Populate toy_list[].
9 
10 #undef NEWTOY
11 #undef OLDTOY
12 #define NEWTOY(name, opts, flags) {#name, name##_main, OPTSTR_##name, flags},
13 #define OLDTOY(name, oldname, flags) \
14   {#name, oldname##_main, OPTSTR_##oldname, flags},
15 
16 struct toy_list toy_list[] = {
17 #include "generated/newtoys.h"
18 };
19 
20 // global context for this command.
21 
22 struct toy_context toys;
23 union global_union this;
24 char *toybox_version = TOYBOX_VERSION, toybuf[4096], libbuf[4096];
25 
toy_find(char * name)26 struct toy_list *toy_find(char *name)
27 {
28   int top, bottom, middle;
29 
30   if (!CFG_TOYBOX || strchr(name, '/')) return 0;
31 
32   // Multiplexer name works as prefix, else skip first entry (it's out of order)
33   if (!toys.which && strstart(&name, "toybox")) return toy_list;
34   bottom = 1;
35 
36   // Binary search to find this command.
37   top = ARRAY_LEN(toy_list)-1;
38   for (;;) {
39     int result;
40 
41     middle = (top+bottom)/2;
42     if (middle<bottom || middle>top) return 0;
43     result = strcmp(name,toy_list[middle].name);
44     if (!result) return toy_list+middle;
45     if (result<0) top = --middle;
46     else bottom = ++middle;
47   }
48 }
49 
50 // Figure out whether or not anything is using the option parsing logic,
51 // because the compiler can't figure out whether or not to optimize it away
52 // on its' own.  NEED_OPTIONS becomes a constant allowing if() to optimize
53 // stuff out via dead code elimination.
54 
55 #undef NEWTOY
56 #undef OLDTOY
57 #define NEWTOY(name, opts, flags) opts ||
58 #define OLDTOY(name, oldname, flags) OPTSTR_##oldname ||
59 static const int NEED_OPTIONS =
60 #include "generated/newtoys.h"
61 0;  // Ends the opts || opts || opts...
62 
unknown(char * name)63 static void unknown(char *name)
64 {
65   toys.exitval = 127;
66   toys.which = toy_list;
67   help_exit("Unknown command %s", name);
68 }
69 
70 // Setup toybox global state for this command.
toy_singleinit(struct toy_list * which,char * argv[])71 void toy_singleinit(struct toy_list *which, char *argv[])
72 {
73   toys.which = which;
74   toys.argv = argv;
75   toys.toycount = ARRAY_LEN(toy_list);
76 
77   // Parse --help and --version for (almost) all commands
78   if (CFG_TOYBOX_HELP_DASHDASH && !(which->flags & TOYFLAG_NOHELP) && argv[1]) {
79     if (!strcmp(argv[1], "--help")) {
80       if (CFG_TOYBOX && toys.which == toy_list && toys.argv[2])
81         if (!(toys.which = toy_find(toys.argv[2]))) unknown(toys.argv[2]);
82       show_help(stdout, 1);
83       xexit();
84     }
85 
86     if (!strcmp(argv[1], "--version")) {
87       xprintf("toybox %s\n", toybox_version);
88       xexit();
89     }
90   }
91 
92   if (NEED_OPTIONS && which->options) get_optflags();
93   else {
94     toys.optargs = argv+1;
95     for (toys.optc = 0; toys.optargs[toys.optc]; toys.optc++);
96   }
97 
98   if (!(CFG_TOYBOX && which == toy_list) && !(which->flags & TOYFLAG_NOFORK)) {
99     toys.old_umask = umask(0);
100     if (!(which->flags & TOYFLAG_UMASK)) umask(toys.old_umask);
101 
102     // Try user's locale, but merge in the en_US.UTF-8 locale's character
103     // type data if the user's locale isn't UTF-8. (We can't merge in C.UTF-8
104     // because that locale doesn't exist on macOS.)
105     setlocale(LC_CTYPE, "");
106     if (strcmp("UTF-8", nl_langinfo(CODESET)))
107       uselocale(newlocale(LC_CTYPE_MASK, "en_US.UTF-8", NULL));
108 
109     setvbuf(stdout, 0, (which->flags & TOYFLAG_LINEBUF) ? _IOLBF : _IONBF, 0);
110   }
111 }
112 
113 // Full init needed by multiplexer or reentrant calls, calls singleinit at end
toy_init(struct toy_list * which,char * argv[])114 void toy_init(struct toy_list *which, char *argv[])
115 {
116   void *oldwhich = toys.which;
117 
118   // Drop permissions for non-suid commands.
119 
120   if (CFG_TOYBOX_SUID) {
121     if (!toys.which) toys.which = toy_list;
122 
123     uid_t uid = getuid(), euid = geteuid();
124 
125     if (!(which->flags & TOYFLAG_STAYROOT)) {
126       if (uid != euid) {
127         if (setuid(uid)) perror_exit("setuid %d->%d", euid, uid); // drop root
128         euid = uid;
129         toys.wasroot++;
130       }
131     } else if (CFG_TOYBOX_DEBUG && uid && which != toy_list)
132       error_msg("Not installed suid root");
133 
134     if ((which->flags & TOYFLAG_NEEDROOT) && euid) help_exit("Not root");
135   }
136 
137   // Free old toys contents (to be reentrant), but leave rebound if any
138   // don't blank old optargs if our new argc lives in the old optargs.
139   if (argv<toys.optargs || argv>toys.optargs+toys.optc) free(toys.optargs);
140   memset(&toys, 0, offsetof(struct toy_context, rebound));
141   if (oldwhich) memset(&this, 0, sizeof(this));
142 
143   // Continue to portion of init needed by standalone commands
144   toy_singleinit(which, argv);
145 }
146 
147 // Run an internal toybox command.
148 // Only returns if it can't run command internally, otherwise xexit() when done.
toy_exec_which(struct toy_list * which,char * argv[])149 static void toy_exec_which(struct toy_list *which, char *argv[])
150 {
151   // Return if we can't find it (which includes no multiplexer case),
152   if (!which || (which->flags&TOYFLAG_NOFORK)) 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   // Signed typecast so stack growth direction is irrelevant: we're measuring
159   // the distance between two pointers on the same stack, hence the labs().
160   if (!CFG_TOYBOX_NORECURSE && toys.stacktop)
161     if (labs((long)toys.stacktop-(long)&which)>6000) return;
162 
163   // Return if we need to re-exec to acquire root via suid bit.
164   if (toys.which && (which->flags&TOYFLAG_ROOTONLY) && toys.wasroot) return;
165 
166   // Run command
167   toy_init(which, argv);
168   if (toys.which) toys.which->toy_main();
169   xexit();
170 }
171 
172 // Lookup internal toybox command to run via argv[0]
toy_exec(char * argv[])173 void toy_exec(char *argv[])
174 {
175   toy_exec_which(toy_find(*argv), argv);
176 }
177 
178 // Multiplexer command, first argument is command to run, rest are args to that.
179 // If first argument starts with - output list of command install paths.
toybox_main(void)180 void toybox_main(void)
181 {
182   char *toy_paths[] = {"usr/", "bin/", "sbin/", 0}, *s = toys.argv[1];
183   int i, len = 0;
184   unsigned width = 80;
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   while (s) {
190     struct toy_list *tl = toy_find(basename(s));
191 
192     if (tl==toy_list && s!=toys.argv[1]) unknown(basename(s));
193     toy_exec_which(toy_find(basename(s)), toys.argv+1);
194     s = (0<readlink(s, libbuf, sizeof(libbuf))) ? libbuf : 0;
195   }
196 
197   // For early error reporting
198   toys.which = toy_list;
199 
200   if (toys.argv[1] && strcmp(toys.argv[1], "--long")) unknown(toys.argv[1]);
201 
202   // Output list of commands.
203   terminal_size(&width, 0);
204   for (i = 1; i<ARRAY_LEN(toy_list); i++) {
205     int fl = toy_list[i].flags;
206     if (fl & TOYMASK_LOCATION) {
207       if (toys.argv[1]) {
208         int j;
209         for (j = 0; toy_paths[j]; j++)
210           if (fl & (1<<j)) len += printf("%s", toy_paths[j]);
211       }
212       len += printf("%s",toy_list[i].name);
213       if (++len > width-15) len = 0;
214       xputc(len ? ' ' : '\n');
215     }
216   }
217   xputc('\n');
218 }
219 
main(int argc,char * argv[])220 int main(int argc, char *argv[])
221 {
222   // don't segfault if our environment is crazy
223   if (!*argv) return 127;
224 
225   // Snapshot stack location so we can detect recursion depth later.
226   // Nommu has special reentry path, !stacktop = "vfork/exec self happened"
227   if (!CFG_TOYBOX_FORK && (0x80 & **argv)) **argv &= 0x7f;
228   else {
229     int stack_start;  // here so probe var won't permanently eat stack
230 
231     toys.stacktop = &stack_start;
232   }
233 
234   // Android before O had non-default SIGPIPE, 7 years = remove in Sep 2024.
235   if (CFG_TOYBOX_ON_ANDROID) signal(SIGPIPE, SIG_DFL);
236 
237   if (CFG_TOYBOX) {
238     // Call the multiplexer with argv[] as its arguments so it can toy_find()
239     toys.argv = argv-1;
240     toybox_main();
241   } else {
242     // single command built standalone with no multiplexer is first list entry
243     toy_singleinit(toy_list, argv);
244     toy_list->toy_main();
245   }
246 
247   xexit();
248 }
249