aboutsummaryrefslogtreecommitdiff
path: root/main.c
blob: 9d892e699db5157d65b65e12be68f78a904dbb6d (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
/* Toybox infrastructure.
 *
 * Copyright 2006 Rob Landley <rob@landley.net>
 */

#include "toys.h"

#ifndef TOYBOX_VERSION
#ifndef TOYBOX_VENDOR
#define TOYBOX_VENDOR ""
#endif
#define TOYBOX_VERSION "0.8.2"TOYBOX_VENDOR
#endif

// Populate toy_list[].

#undef NEWTOY
#undef OLDTOY
#define NEWTOY(name, opts, flags) {#name, name##_main, OPTSTR_##name, flags},
#define OLDTOY(name, oldname, flags) \
  {#name, oldname##_main, OPTSTR_##oldname, flags},

struct toy_list toy_list[] = {
#include "generated/newtoys.h"
};

// global context for this command.

struct toy_context toys;
union global_union this;
char toybuf[4096], libbuf[4096];

struct toy_list *toy_find(char *name)
{
  int top, bottom, middle;

  if (!CFG_TOYBOX || strchr(name, '/')) return 0;

  // If the name starts with "toybox" accept that as a match.  Otherwise
  // skip the first entry, which is out of order.

  if (!strncmp(name, "toybox", 6)) return toy_list;
  bottom = 1;

  // Binary search to find this command.

  top = ARRAY_LEN(toy_list)-1;
  for (;;) {
    int result;

    middle = (top+bottom)/2;
    if (middle<bottom || middle>top) return 0;
    result = strcmp(name,toy_list[middle].name);
    if (!result) return toy_list+middle;
    if (result<0) top = --middle;
    else bottom = ++middle;
  }
}

// Figure out whether or not anything is using the option parsing logic,
// because the compiler can't figure out whether or not to optimize it away
// on its' own.  NEED_OPTIONS becomes a constant allowing if() to optimize
// stuff out via dead code elimination.

#undef NEWTOY
#undef OLDTOY
#define NEWTOY(name, opts, flags) opts ||
#define OLDTOY(name, oldname, flags) OPTSTR_##oldname ||
static const int NEED_OPTIONS =
#include "generated/newtoys.h"
0;  // Ends the opts || opts || opts...

static void unknown(char *name)
{
  toys.exitval = 127;
  toys.which = toy_list;
  error_exit("Unknown command %s", name);
}

// Setup toybox global state for this command.
static void toy_singleinit(struct toy_list *which, char *argv[])
{
  toys.which = which;
  toys.argv = argv;
  toys.toycount = ARRAY_LEN(toy_list);

  // Parse --help and --version for (almost) all commands
  if (CFG_TOYBOX_HELP_DASHDASH && !(which->flags & TOYFLAG_NOHELP) && argv[1]) {
    if (!strcmp(argv[1], "--help")) {
      if (CFG_TOYBOX && toys.which == toy_list && toys.argv[2])
        if (!(toys.which = toy_find(toys.argv[2]))) unknown(toys.argv[2]);
      show_help(stdout);
      xexit();
    }

    if (!strcmp(argv[1], "--version")) {
      xputs("toybox "TOYBOX_VERSION);
      xexit();
    }
  }

  if (NEED_OPTIONS && which->options) get_optflags();
  else {
    toys.optargs = argv+1;
    for (toys.optc = 0; toys.optargs[toys.optc]; toys.optc++);
  }

  if (!(which->flags & TOYFLAG_NOFORK)) {
    toys.old_umask = umask(0);
    if (!(which->flags & TOYFLAG_UMASK)) umask(toys.old_umask);
    if (CFG_TOYBOX_I18N) {
      // Deliberately try C.UTF-8 before the user's locale to work around users
      // that choose non-UTF-8 locales. macOS doesn't support C.UTF-8 though.
      if (!setlocale(LC_CTYPE, "C.UTF-8")) setlocale(LC_CTYPE, "");
    }
    setlinebuf(stdout);
  }
}

// Full init needed by multiplexer or reentrant calls, calls singleinit at end
void toy_init(struct toy_list *which, char *argv[])
{
  void *oldwhich = toys.which;

  // Drop permissions for non-suid commands.

  if (CFG_TOYBOX_SUID) {
    if (!toys.which) toys.which = toy_list;

    uid_t uid = getuid(), euid = geteuid();

    if (!(which->flags & TOYFLAG_STAYROOT)) {
      if (uid != euid) {
        if (setuid(uid)) perror_exit("setuid %d->%d", euid, uid); // drop root
        euid = uid;
        toys.wasroot++;
      }
    } else if (CFG_TOYBOX_DEBUG && uid && which != toy_list)
      error_msg("Not installed suid root");

    if ((which->flags & TOYFLAG_NEEDROOT) && euid) help_exit("Not root");
  }

  // Free old toys contents (to be reentrant), but leave rebound if any
  // don't blank old optargs if our new argc lives in the old optargs.
  if (argv<toys.optargs || argv>toys.optargs+toys.optc) free(toys.optargs);
  memset(&toys, 0, offsetof(struct toy_context, rebound));
  if (oldwhich) memset(&this, 0, sizeof(this));

  // Continue to portion of init needed by standalone commands
  toy_singleinit(which, argv);
}

// Run an internal toybox command.
// Only returns if it can't run command internally, otherwise xexit() when done.
void toy_exec_which(struct toy_list *which, char *argv[])
{
  // Return if we can't find it (which includes no multiplexer case),
  if (!which) return;

  // Return if stack depth getting noticeable (proxy for leaked heap, etc).

  // Compiler writers have decided subtracting char * is undefined behavior,
  // so convert to integers. (LP64 says sizeof(long)==sizeof(pointer).)
  // Signed typecast so stack growth direction is irrelevant: we're measuring
  // the distance between two pointers on the same stack, hence the labs().
  if (!CFG_TOYBOX_NORECURSE && toys.stacktop)
    if (labs((long)toys.stacktop-(long)&which)>6000) return;

  // Return if we need to re-exec to acquire root via suid bit.
  if (toys.which && (which->flags&TOYFLAG_ROOTONLY) && toys.wasroot) return;

  // Run command
  toy_init(which, argv);
  if (toys.which) toys.which->toy_main();
  xexit();
}

// Lookup internal toybox command to run via argv[0]
void toy_exec(char *argv[])
{
  toy_exec_which(toy_find(basename(*argv)), argv);
}

// Multiplexer command, first argument is command to run, rest are args to that.
// If first argument starts with - output list of command install paths.
void toybox_main(void)
{
  static char *toy_paths[]={"usr/","bin/","sbin/",0};
  int i, len = 0;

  // fast path: try to exec immediately.
  // (Leave toys.which null to disable suid return logic.)
  // Try dereferencing one layer of symlink
  if (toys.argv[1]) {
    toy_exec(toys.argv+1);
    if (0<readlink(toys.argv[1], libbuf, sizeof(libbuf))) {
      struct toy_list *tl= toy_find(basename(libbuf));

      if (tl == toy_list) unknown(basename(toys.argv[1]));
      else toy_exec_which(tl, toys.argv+1);
    }
  }

  // For early error reporting
  toys.which = toy_list;

  if (toys.argv[1] && toys.argv[1][0] != '-') unknown(toys.argv[1]);

  // Output list of command.
  for (i=1; i<ARRAY_LEN(toy_list); i++) {
    int fl = toy_list[i].flags;
    if (fl & TOYMASK_LOCATION) {
      if (toys.argv[1]) {
        int j;
        for (j=0; toy_paths[j]; j++)
          if (fl & (1<<j)) len += printf("%s", toy_paths[j]);
      }
      len += printf("%s",toy_list[i].name);
      if (++len > 65) len = 0;
      xputc(len ? ' ' : '\n');
    }
  }
  xputc('\n');
}

int main(int argc, char *argv[])
{
  if (!*argv) return 127;

  // Snapshot stack location so we can detect recursion depth later.
  // This is its own block so probe doesn't permanently consume stack.
  else {
    int stack;

    toys.stacktop = &stack;
  }

  // Up to and including Android M, bionic's dynamic linker added a handler to
  // cause a crash dump on SIGPIPE. That was removed in Android N, but adbd
  // was still setting the SIGPIPE disposition to SIG_IGN, and its children
  // were inheriting that. In Android O, adbd is fixed, but manually asking
  // for the default disposition is harmless, and it'll be a long time before
  // no one's using anything older than O!
  if (CFG_TOYBOX_ON_ANDROID) signal(SIGPIPE, SIG_DFL);

  // If nommu can't fork, special reentry path.
  // Use !stacktop to signal "vfork happened", both before and after xexec()
  if (!CFG_TOYBOX_FORK) {
    if (0x80 & **argv) {
      **argv &= 0x7f;
      toys.stacktop = 0;
    }
  }

  if (CFG_TOYBOX) {
    // Call the multiplexer, adjusting this argv[] to be its' argv[1].
    // (It will adjust it back before calling toy_exec().)
    toys.argv = argv-1;
    toybox_main();
  } else {
    // a single toybox command built standalone with no multiplexer
    toy_singleinit(toy_list, argv);
    toy_list->toy_main();
  }

  xexit();
}