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 16struct toy_list toy_list[] = { 17#include "generated/newtoys.h" 18}; 19 20// global context for this command. 21 22struct toy_context toys; 23union global_union this; 24char toybuf[4096], libbuf[4096]; 25 26struct toy_list *toy_find(char *name) 27{ 28 int top, bottom, middle; 29 30 if (!CFG_TOYBOX || strchr(name, '/')) return 0; 31 32 // If the name starts with "toybox" accept that as a match. Otherwise 33 // skip the first entry, which is out of order. 34 35 if (!strncmp(name, "toybox", 6)) return toy_list; 36 bottom = 1; 37 38 // Binary search to find this command. 39 40 top = ARRAY_LEN(toy_list)-1; 41 for (;;) { 42 int result; 43 44 middle = (top+bottom)/2; 45 if (middle<bottom || middle>top) return 0; 46 result = strcmp(name,toy_list[middle].name); 47 if (!result) return toy_list+middle; 48 if (result<0) top = --middle; 49 else bottom = ++middle; 50 } 51} 52 53// Figure out whether or not anything is using the option parsing logic, 54// because the compiler can't figure out whether or not to optimize it away 55// on its' own. NEED_OPTIONS becomes a constant allowing if() to optimize 56// stuff out via dead code elimination. 57 58#undef NEWTOY 59#undef OLDTOY 60#define NEWTOY(name, opts, flags) opts || 61#define OLDTOY(name, oldname, flags) OPTSTR_##oldname || 62static const int NEED_OPTIONS = 63#include "generated/newtoys.h" 640; // Ends the opts || opts || opts... 65 66static void unknown(char *name) 67{ 68 toys.exitval = 127; 69 toys.which = toy_list; 70 error_exit("Unknown command %s", name); 71} 72 73// Setup toybox global state for this command. 74static void toy_singleinit(struct toy_list *which, char *argv[]) 75{ 76 toys.which = which; 77 toys.argv = argv; 78 79 if (CFG_TOYBOX_I18N) setlocale(LC_CTYPE, "C.UTF-8"); 80 setlinebuf(stdout); 81 82 // Parse --help and --version for (almost) all commands 83 if (CFG_TOYBOX_HELP_DASHDASH && !(which->flags & TOYFLAG_NOHELP) && argv[1]) { 84 if (!strcmp(argv[1], "--help")) { 85 if (CFG_TOYBOX && toys.which == toy_list && toys.argv[2]) 86 if (!(toys.which = toy_find(toys.argv[2]))) unknown(toys.argv[2]); 87 show_help(stdout); 88 xexit(); 89 } 90 91 if (!strcmp(argv[1], "--version")) { 92 xputs("toybox "TOYBOX_VERSION); 93 xexit(); 94 } 95 } 96 97 if (NEED_OPTIONS && which->options) get_optflags(); 98 else { 99 toys.optargs = argv+1; 100 for (toys.optc = 0; toys.optargs[toys.optc]; toys.optc++); 101 } 102 toys.old_umask = umask(0); 103 if (!(which->flags & TOYFLAG_UMASK)) umask(toys.old_umask); 104 toys.signalfd--; 105 toys.toycount = ARRAY_LEN(toy_list); 106} 107 108// Full init needed by multiplexer or reentrant calls, calls singleinit at end 109void toy_init(struct toy_list *which, char *argv[]) 110{ 111 void *oldwhich = toys.which; 112 113 // Drop permissions for non-suid commands. 114 115 if (CFG_TOYBOX_SUID) { 116 if (!toys.which) toys.which = toy_list; 117 118 uid_t uid = getuid(), euid = geteuid(); 119 120 if (!(which->flags & TOYFLAG_STAYROOT)) { 121 if (uid != euid) { 122 if (setuid(uid)) perror_exit("setuid %d->%d", euid, uid); // drop root 123 euid = uid; 124 toys.wasroot++; 125 } 126 } else if (CFG_TOYBOX_DEBUG && uid && which != toy_list) 127 error_msg("Not installed suid root"); 128 129 if ((which->flags & TOYFLAG_NEEDROOT) && euid) help_exit("Not root"); 130 } 131 132 // Free old toys contents (to be reentrant), but leave rebound if any 133 // don't blank old optargs if our new argc lives in the old optargs. 134 if (argv<toys.optargs || argv>toys.optargs+toys.optc) free(toys.optargs); 135 memset(&toys, 0, offsetof(struct toy_context, rebound)); 136 if (oldwhich) memset(&this, 0, sizeof(this)); 137 138 // Continue to portion of init needed by standalone commands 139 toy_singleinit(which, argv); 140} 141 142// Run an internal toybox command. 143// Only returns if it can't run command internally, otherwise xexit() when done. 144void toy_exec_which(struct toy_list *which, char *argv[]) 145{ 146 // Return if we can't find it (which includes no multiplexer case), 147 if (!which) return; 148 149 // Return if stack depth getting noticeable (proxy for leaked heap, etc). 150 151 // Compiler writers have decided subtracting char * is undefined behavior, 152 // so convert to integers. (LP64 says sizeof(long)==sizeof(pointer).) 153 // Signed typecast so stack growth direction is irrelevant: we're measuring 154 // the distance between two pointers on the same stack, hence the labs(). 155 if (!CFG_TOYBOX_NORECURSE && toys.stacktop) 156 if (labs((long)toys.stacktop-(long)&which)>6000) return; 157 158 // Return if we need to re-exec to acquire root via suid bit. 159 if (toys.which && (which->flags&TOYFLAG_ROOTONLY) && toys.wasroot) return; 160 161 // Run command 162 toy_init(which, argv); 163 if (toys.which) toys.which->toy_main(); 164 xexit(); 165} 166 167// Lookup internal toybox command to run via argv[0] 168void toy_exec(char *argv[]) 169{ 170 toy_exec_which(toy_find(basename(*argv)), argv); 171} 172 173// Multiplexer command, first argument is command to run, rest are args to that. 174// If first argument starts with - output list of command install paths. 175void toybox_main(void) 176{ 177 static char *toy_paths[]={"usr/","bin/","sbin/",0}; 178 int i, len = 0; 179 180 // fast path: try to exec immediately. 181 // (Leave toys.which null to disable suid return logic.) 182 // Try dereferencing one layer of symlink 183 if (toys.argv[1]) { 184 toy_exec(toys.argv+1); 185 if (0<readlink(toys.argv[1], libbuf, sizeof(libbuf))) { 186 struct toy_list *tl= toy_find(basename(libbuf)); 187 188 if (tl == toy_list) unknown(basename(toys.argv[1])); 189 else toy_exec_which(tl, toys.argv+1); 190 } 191 } 192 193 // For early error reporting 194 toys.which = toy_list; 195 196 if (toys.argv[1] && toys.argv[1][0] != '-') unknown(toys.argv[1]); 197 198 // Output list of command. 199 for (i=1; i<ARRAY_LEN(toy_list); i++) { 200 int fl = toy_list[i].flags; 201 if (fl & TOYMASK_LOCATION) { 202 if (toys.argv[1]) { 203 int j; 204 for (j=0; toy_paths[j]; j++) 205 if (fl & (1<<j)) len += printf("%s", toy_paths[j]); 206 } 207 len += printf("%s",toy_list[i].name); 208 if (++len > 65) len = 0; 209 xputc(len ? ' ' : '\n'); 210 } 211 } 212 xputc('\n'); 213} 214 215int main(int argc, char *argv[]) 216{ 217 if (!*argv) return 127; 218 219 // Snapshot stack location so we can detect recursion depth later. 220 // This is its own block so probe doesn't permanently consume stack. 221 else { 222 int stack; 223 224 toys.stacktop = &stack; 225 } 226 227 // Up to and including Android M, bionic's dynamic linker added a handler to 228 // cause a crash dump on SIGPIPE. That was removed in Android N, but adbd 229 // was still setting the SIGPIPE disposition to SIG_IGN, and its children 230 // were inheriting that. In Android O, adbd is fixed, but manually asking 231 // for the default disposition is harmless, and it'll be a long time before 232 // no one's using anything older than O! 233 if (CFG_TOYBOX_ON_ANDROID) signal(SIGPIPE, SIG_DFL); 234 235 // If nommu can't fork, special reentry path. 236 // Use !stacktop to signal "vfork happened", both before and after xexec() 237 if (!CFG_TOYBOX_FORK) { 238 if (0x80 & **argv) { 239 **argv &= 0x7f; 240 toys.stacktop = 0; 241 } 242 } 243 244 if (CFG_TOYBOX) { 245 // Call the multiplexer, adjusting this argv[] to be its' argv[1]. 246 // (It will adjust it back before calling toy_exec().) 247 toys.argv = argv-1; 248 toybox_main(); 249 } else { 250 // a single toybox command built standalone with no multiplexer 251 toy_singleinit(toy_list, argv); 252 toy_list->toy_main(); 253 } 254 255 xexit(); 256} 257