Fix phony dependency

[android-x86/external-toybox.git] / main.c

diff --git a/main.c b/main.c
index dcd486e..eeae2f3 100644 (file)
--- a/main.c
+++ b/main.c
@@ -6,7 +6,7 @@
 #include "toys.h"
 
 #ifndef TOYBOX_VERSION
-#define TOYBOX_VERSION "0.6.0"
+#define TOYBOX_VERSION "0.7.0"
 #endif
 
 // Populate toy_list[].
@@ -67,7 +67,7 @@ static const int NEED_OPTIONS =
 #include "generated/newtoys.h"
 0;  // Ends the opts || opts || opts...
 
-// Subset of init needed by singlemain
+// Setup toybox global state for this command.
 static void toy_singleinit(struct toy_list *which, char *argv[])
 {
   toys.which = which;
@@ -85,7 +85,7 @@ static void toy_singleinit(struct toy_list *which, char *argv[])
   if (NEED_OPTIONS && which->options) get_optflags();
   else {
     toys.optargs = argv+1;
-    for (toys.optc=0; toys.optargs[toys.optc]; toys.optc++);
+    for (toys.optc = 0; toys.optargs[toys.optc]; toys.optc++);
   }
   toys.old_umask = umask(0);
   if (!(which->flags & TOYFLAG_UMASK)) umask(toys.old_umask);
@@ -93,19 +93,23 @@ static void toy_singleinit(struct toy_list *which, char *argv[])
   toys.toycount = ARRAY_LEN(toy_list);
 }
 
-// Setup toybox global state for this command.
-
+// 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
-        else euid = uid;
+        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");
@@ -114,12 +118,12 @@ void toy_init(struct toy_list *which, char *argv[])
   }
 
   // Free old toys contents (to be reentrant), but leave rebound if any
-
-  if (toys.optargs != toys.argv+1) free(toys.optargs);
+  // 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 (toys.recursion > 1) memset(&this, 0, sizeof(this));
+  if (oldwhich) memset(&this, 0, sizeof(this));
 
-  // Subset of init needed by singlemain.
+  // Continue to portion of init needed by standalone commands
   toy_singleinit(which, argv);
 }
 
@@ -129,14 +133,18 @@ void toy_exec(char *argv[])
 {
   struct toy_list *which;
 
-  // Return if we can't find it, or need to re-exec to acquire root,
-  // or if stack depth is getting silly.
-  if (!(which = toy_find(argv[0]))) return;
-  if (toys.recursion && (which->flags & TOYFLAG_ROOTONLY) && getuid()) return;
-  if (toys.recursion++ > 5) return;
+  // Return if we can't find it (which includes no multiplexer case),
+  if (!(which = toy_find(*argv))) return;
 
-  // don't blank old optargs if our new argc lives in the old optargs.
-  if (argv>=toys.optargs && argv<=toys.optargs+toys.optc) toys.optargs = 0;
+  // 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).)
+  if (!CFG_TOYBOX_NORECURSE)
+    if (toys.stacktop && 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);
@@ -146,16 +154,19 @@ void toy_exec(char *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.)
+  if (toys.argv[1]) toy_exec(toys.argv+1);
+
+  // For early error reporting
   toys.which = toy_list;
+
   if (toys.argv[1]) {
-    toys.optc = toys.recursion = 0;
-    toy_exec(toys.argv+1);
     if (!strcmp("--version", toys.argv[1])) {
       xputs(TOYBOX_VERSION);
       xexit();
@@ -185,13 +196,27 @@ void toybox_main(void)
 
 int main(int argc, char *argv[])
 {
-  // We check our own stdout errors, disable sigpipe killer
-  signal(SIGPIPE, SIG_IGN);
+  if (!*argv) return 127;
 
-  if (CFG_TOYBOX) {
-    // Trim path off of command name
-    *argv = basename(*argv);
+  // 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;
+  }
+  *argv = getbasename(*argv);
+
+  // 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;