hush: do not allow sh -c '{ echo boo }'

[oweals/busybox.git] / shell / ash.c

diff --git a/shell/ash.c b/shell/ash.c
index fc1b5d9275d54a5b8c532d9554439491616389b3..87f2127a1f491d81da431e2692a2bbe8cb94a0dd 100644 (file)
--- a/shell/ash.c
+++ b/shell/ash.c
@@ -32,6 +32,7 @@
 #define DEBUG_TIME 0
 #define DEBUG_PID 1
 #define DEBUG_SIG 1
+#define DEBUG_INTONOFF 0
 
 #define PROFILE 0
 
@@ -442,10 +443,18 @@ static void exitshell(void) NORETURN;
  * much more efficient and portable.  (But hacking the kernel is so much
  * more fun than worrying about efficiency and portability. :-))
  */
-#define INT_OFF do { \
+#if DEBUG_INTONOFF
+# define INT_OFF do { \
+       TRACE(("%s:%d INT_OFF(%d)\n", __func__, __LINE__, suppress_int)); \
        suppress_int++; \
        barrier(); \
 } while (0)
+#else
+# define INT_OFF do { \
+       suppress_int++; \
+       barrier(); \
+} while (0)
+#endif
 
 /*
  * Called to raise an exception.  Since C doesn't include exceptions, we
@@ -513,7 +522,14 @@ int_on(void)
                raise_interrupt();
        }
 }
-#define INT_ON int_on()
+#if DEBUG_INTONOFF
+# define INT_ON do { \
+       TRACE(("%s:%d INT_ON(%d)\n", __func__, __LINE__, suppress_int-1)); \
+       int_on(); \
+} while (0)
+#else
+# define INT_ON int_on()
+#endif
 static IF_ASH_OPTIMIZE_FOR_SIZE(inline) void
 force_int_on(void)
 {
@@ -844,13 +860,8 @@ trace_vprintf(const char *fmt, va_list va)
 {
        if (debug != 1)
                return;
-       if (DEBUG_TIME)
-               fprintf(tracefile, "%u ", (int) time(NULL));
-       if (DEBUG_PID)
-               fprintf(tracefile, "[%u] ", (int) getpid());
-       if (DEBUG_SIG)
-               fprintf(tracefile, "pending s:%d i:%d(supp:%d) ", pending_sig, pending_int, suppress_int);
        vfprintf(tracefile, fmt, va);
+       fprintf(tracefile, "\n");
 }
 
 static void
@@ -1243,11 +1254,10 @@ ash_vmsg_and_raise(int cond, const char *msg, va_list ap)
 {
 #if DEBUG
        if (msg) {
-               TRACE(("ash_vmsg_and_raise(%d, \"", cond));
+               TRACE(("ash_vmsg_and_raise(%d):", cond));
                TRACEV((msg, ap));
-               TRACE(("\") pid=%d\n", getpid()));
        } else
-               TRACE(("ash_vmsg_and_raise(%d, NULL) pid=%d\n", cond, getpid()));
+               TRACE(("ash_vmsg_and_raise(%d):NULL\n", cond));
        if (msg)
 #endif
                ash_vmsg(msg, ap);
@@ -3939,6 +3949,8 @@ wait_block_or_sig(int *status)
        int pid;
 
        do {
+               sigset_t mask;
+
                /* Poll all children for changes in their state */
                got_sigchld = 0;
                /* if job control is active, accept stopped processes too */
@@ -3947,14 +3959,13 @@ wait_block_or_sig(int *status)
                        break; /* Error (e.g. EINTR, ECHILD) or pid */
 
                /* Children exist, but none are ready. Sleep until interesting signal */
-#if 0 /* dash does this */
-               sigset_t mask;
+#if 1
                sigfillset(&mask);
                sigprocmask(SIG_SETMASK, &mask, &mask);
                while (!got_sigchld && !pending_sig)
                        sigsuspend(&mask);
                sigprocmask(SIG_SETMASK, &mask, NULL);
-#else
+#else /* unsafe: a signal can set pending_sig after check, but before pause() */
                while (!got_sigchld && !pending_sig)
                        pause();
 #endif
@@ -3993,9 +4004,9 @@ dowait(int block, struct job *job)
         * either enter a sleeping waitpid() (BUG), or need to busy-loop.
         *
         * Because of this, we run inside INT_OFF, but use a special routine
-        * which combines waitpid() and pause().
+        * which combines waitpid() and sigsuspend().
         * This is the reason why we need to have a handler for SIGCHLD:
-        * SIG_DFL handler does not wake pause().
+        * SIG_DFL handler does not wake sigsuspend().
         */
        INT_OFF;
        if (block == DOWAIT_BLOCK_OR_SIG) {
@@ -7053,6 +7064,21 @@ expandmeta(struct strlist *str /*, int flag*/)
 
                if (fflag)
                        goto nometa;
+
+               /* Avoid glob() (and thus, stat() et al) for words like "echo" */
+               p = str->text;
+               while (*p) {
+                       if (*p == '*')
+                               goto need_glob;
+                       if (*p == '?')
+                               goto need_glob;
+                       if (*p == '[')
+                               goto need_glob;
+                       p++;
+               }
+               goto nometa;
+
+ need_glob:
                INT_OFF;
                p = preglob(str->text, RMESCAPE_ALLOC | RMESCAPE_HEAP);
 // GLOB_NOMAGIC (GNU): if no *?[ chars in pattern, return it even if no match
@@ -9091,7 +9117,7 @@ mklocal(char *name)
                        /* else:
                         * it's a duplicate "local VAR" declaration, do nothing
                         */
-                       return;
+                       goto ret;
                }
                lvp = lvp->next;
        }
@@ -9130,6 +9156,7 @@ mklocal(char *name)
        lvp->vp = vp;
        lvp->next = localvars;
        localvars = lvp;
+ ret:
        INT_ON;
 }
 
@@ -10125,6 +10152,9 @@ popfile(void)
 {
        struct parsefile *pf = g_parsefile;
 
+       if (pf == &basepf)
+               return;
+
        INT_OFF;
        if (pf->pf_fd >= 0)
                close(pf->pf_fd);
@@ -12286,7 +12316,7 @@ expandstr(const char *ps)
 static int
 evalstring(char *s, int flags)
 {
-       struct jmploc *volatile savehandler = exception_handler;
+       struct jmploc *volatile savehandler;
        struct jmploc jmploc;
        int ex;
 
@@ -12307,10 +12337,10 @@ evalstring(char *s, int flags)
         * But if we skip popfile(), we hit EOF in eval's string, and exit.
         */
        savehandler = exception_handler;
-       exception_handler = &jmploc;
        ex = setjmp(jmploc.loc);
        if (ex)
                goto out;
+       exception_handler = &jmploc;
 
        while ((n = parsecmd(0)) != NODE_EOF) {
                int i;
@@ -13419,16 +13449,15 @@ int ash_main(int argc UNUSED_PARAM, char **argv)
                goto state4;
        }
        exception_handler = &jmploc;
-#if DEBUG
-       opentrace();
-       TRACE(("Shell args: "));
-       trace_puts_args(argv);
-#endif
        rootpid = getpid();
 
        init();
        setstackmark(&smark);
        procargs(argv);
+#if DEBUG
+       TRACE(("Shell args: "));
+       trace_puts_args(argv);
+#endif
 
        if (argv[0] && argv[0][0] == '-')
                isloginsh = 1;