hush: fix environment and memory leaks, add tests for them

function                                             old     new   delta
add_malloced_string_to_strings                         -     110    +110
run_list                                            1999    2086     +87
free_strings_and_unsetenv                              -      87     +87
hush_version_str                                       -      18     +18
pseudo_exec_argv                                     139     146      +7
static.version_str                                    17       -     -17
free_pipe                                            237     210     -27
done_word                                            790     642    -148
------------------------------------------------------------------------------
(add/remove: 3/1 grow/shrink: 2/2 up/down: 309/-192)          Total: 117 bytes

6 files changed, 218 insertions, 58 deletions

diff --git a/shell/hush.c b/shell/hush.c
index d5955dd93..7cf2f3322 100644
--- a/shell/hush.c
+++ b/shell/hush.c
@@ -54,7 +54,7 @@
  *      port selected bugfixes from post-0.49 busybox lash - done?
  *      change { and } from special chars to reserved words
  *      builtins: return, trap, ulimit
- *      test magic exec
+ *      test magic exec with redirection only
  *      check setting of global_argc and global_argv
  *      follow IFS rules more precisely, including update semantics
  *      figure out what to do with backslash-newline
@@ -73,7 +73,7 @@
 #include <fnmatch.h>
 #endif
 
-#define HUSH_VER_STR "0.9"
+#define HUSH_VER_STR "0.91"
 
 #if !BB_MMU && ENABLE_HUSH_TICK
 //#undef ENABLE_HUSH_TICK
@@ -525,13 +525,13 @@ static int free_pipe(struct pipe *pi, int indent);
 static int setup_redirects(struct command *prog, int squirrel[]);
 static int run_list(struct pipe *pi);
 #if BB_MMU
-#define pseudo_exec_argv(ptrs2free, argv, assignment_cnt, argv_expanded) \
+#define pseudo_exec_argv(ptr_ptrs2free, argv, assignment_cnt, argv_expanded) \
         pseudo_exec_argv(argv, assignment_cnt, argv_expanded)
-#define pseudo_exec(ptrs2free, command, argv_expanded) \
+#define pseudo_exec(ptr_ptrs2free, command, argv_expanded) \
         pseudo_exec(command, argv_expanded)
 #endif
-static void pseudo_exec_argv(char **ptrs2free, char **argv, int assignment_cnt, char **argv_expanded) NORETURN;
-static void pseudo_exec(char **ptrs2free, struct command *command, char **argv_expanded) NORETURN;
+static void pseudo_exec_argv(char ***ptr_ptrs2free, char **argv, int assignment_cnt, char **argv_expanded) NORETURN;
+static void pseudo_exec(char ***ptr_ptrs2free, struct command *command, char **argv_expanded) NORETURN;
 static int run_pipe(struct pipe *pi);
 /*   data structure manipulation: */
 static int setup_redirect(struct parse_context *ctx, int fd, redir_type style, struct in_str *input);
@@ -576,6 +576,9 @@ static int set_local_var(char *str, int flg_export);
 static void unset_local_var(const char *name);
 
 
+static const char hush_version_str[] ALIGN1 = "HUSH_VERSION="HUSH_VER_STR;
+
+
 static int glob_needed(const char *s)
 {
         while (*s) {
@@ -650,26 +653,44 @@ static char **add_malloced_string_to_strings(char **strings, char *add)
         return add_malloced_strings_to_strings(strings, v);
 }
 
-static void free_strings(char **strings)
+static void free_strings_and_unsetenv(char **strings, int unset)
 {
-        if (strings) {
-                char **v = strings;
-                while (*v)
-                        free(*v++);
-                free(strings);
+        char **v;
+
+        if (!strings)
+                return;
+
+        v = strings;
+        while (*v) {
+                if (unset) {
+                        char *copy;
+#if !BB_MMU
+                        /* If this is a magic guard pointer, do not free it,
+                         * and stop unsetting */
+                        if (*v == hush_version_str) {
+                                unset = 0;
+                                v++;
+                                continue;
+                        }
+#endif
+                        /* *strchrnul(*v, '=') = '\0'; -- BAD
+                         * In case *v was putenv'ed, we can't
+                         * unsetenv(*v) after taking out '=':
+                         * it won't work, env is modified by taking out!
+                         * horror :( */
+                        copy = xstrndup(*v, strchrnul(*v, '=') - *v);
+                        unsetenv(copy);
+                        free(copy);
+                }
+                free(*v++);
         }
+        free(strings);
 }
 
-#if !BB_MMU
-#define EXTRA_PTRS 5 /* 1 for NULL, 1 for args, 3 for paranoid reasons */
-static char **alloc_ptrs(char **argv)
+static void free_strings(char **strings)
 {
-        char **v = argv;
-        while (*v)
-                v++;
-        return xzalloc((v - argv + EXTRA_PTRS) * sizeof(v[0]));
+        free_strings_and_unsetenv(strings, 0);
 }
-#endif
 
 
 /* Function prototypes for builtins */
@@ -1393,34 +1414,36 @@ static void restore_redirects(int squirrel[])
  * XXX no exit() here.  If you don't exec, use _exit instead.
  * The at_exit handlers apparently confuse the calling process,
  * in particular stdin handling.  Not sure why? -- because of vfork! (vda) */
-static void pseudo_exec_argv(char **ptrs2free, char **argv, int assignment_cnt, char **argv_expanded)
+static void pseudo_exec_argv(char ***ptr_ptrs2free, char **argv, int assignment_cnt, char **argv_expanded)
 {
         int i, rcode;
         char *p;
         const struct built_in_command *x;
 
-        for (i = 0; i < assignment_cnt; i++) {
-                debug_printf_exec("pid %d environment modification: %s\n",
-                                getpid(), argv[i]);
-                p = expand_string_to_string(argv[i]);
-#if !BB_MMU
-                *ptrs2free++ = p;
-#endif
-                putenv(p);
-        }
-        argv += i;
         /* If a variable is assigned in a forest, and nobody listens,
          * was it ever really set?
          */
-        if (!argv[0])
+        if (!argv[assignment_cnt])
                 _exit(EXIT_SUCCESS);
 
+        for (i = 0; i < assignment_cnt; i++) {
+                debug_printf_exec("pid %d environment modification: %s\n",
+                                getpid(), *argv);
+                p = expand_string_to_string(*argv);
+                putenv(p);
+#if !BB_MMU
+                *ptr_ptrs2free = add_malloced_string_to_strings(*ptr_ptrs2free, p);
+#endif
+                argv++;
+        }
         if (argv_expanded) {
                 argv = argv_expanded;
         } else {
                 argv = expand_strvec_to_strvec(argv);
 #if !BB_MMU
-                *ptrs2free++ = (char*) argv;
+                /* Inserting magic guard pointer to not unsetenv junk later */
+                *ptr_ptrs2free = add_malloced_string_to_strings(*ptr_ptrs2free, (char*)hush_version_str);
+                *ptr_ptrs2free = add_malloced_string_to_strings(*ptr_ptrs2free, (char*)argv);
 #endif
         }
 
@@ -1466,10 +1489,10 @@ static void pseudo_exec_argv(char **ptrs2free, char **argv, int assignment_cnt,
 
 /* Called after [v]fork() in run_pipe()
  */
-static void pseudo_exec(char **ptrs2free, struct command *command, char **argv_expanded)
+static void pseudo_exec(char ***ptr_ptrs2free, struct command *command, char **argv_expanded)
 {
         if (command->argv)
-                pseudo_exec_argv(ptrs2free, command->argv, command->assignment_cnt, argv_expanded);
+                pseudo_exec_argv(ptr_ptrs2free, command->argv, command->assignment_cnt, argv_expanded);
 
         if (command->group) {
 #if !BB_MMU
@@ -1745,6 +1768,7 @@ static int run_pipe(struct pipe *pi)
         int nextin;
         int pipefds[2];         /* pipefds[0] is for reading */
         struct command *command;
+        char **ptrs2free = NULL;
         char **argv_expanded = NULL;
         char **argv;
         const struct built_in_command *x;
@@ -1796,7 +1820,7 @@ static int run_pipe(struct pipe *pi)
                 for (i = 0; i < command->assignment_cnt; i++) {
                         p = expand_string_to_string(argv[i]);
                         putenv(p);
-//FIXME: do we leak p?!
+                        ptrs2free = add_malloced_string_to_strings(ptrs2free, p);
                 }
 
                 /* Expand the rest into (possibly) many strings each */
@@ -1805,9 +1829,10 @@ static int run_pipe(struct pipe *pi)
                 for (x = bltins; x != &bltins[ARRAY_SIZE(bltins)]; x++) {
                         if (strcmp(argv_expanded[0], x->cmd) == 0) {
                                 if (x->function == builtin_exec && argv_expanded[1] == NULL) {
-                                        debug_printf("magic exec\n");
+                                        debug_printf("exec with redirects only\n");
                                         setup_redirects(command, NULL);
-                                        return EXIT_SUCCESS;
+                                        rcode = EXIT_SUCCESS;
+                                        goto clean_up_and_ret1;
                                 }
                                 debug_printf("builtin inline %s\n", argv_expanded[0]);
                                 /* XXX setup_redirects acts on file descriptors, not FILEs.
@@ -1817,10 +1842,13 @@ static int run_pipe(struct pipe *pi)
                                 setup_redirects(command, squirrel);
                                 debug_printf_exec(": builtin '%s' '%s'...\n", x->cmd, argv_expanded[1]);
                                 rcode = x->function(argv_expanded) & 0xff;
-                                free(argv_expanded);
+ USE_FEATURE_SH_STANDALONE(clean_up_and_ret:)
                                 restore_redirects(squirrel);
-                                debug_printf_exec("run_pipe return %d\n", rcode);
+ clean_up_and_ret1:
+                                free_strings_and_unsetenv(ptrs2free, 1);
+                                free(argv_expanded);
                                 IF_HAS_KEYWORDS(if (pi->pi_inverted) rcode = !rcode;)
+                                debug_printf_exec("run_pipe return %d\n", rcode);
                                 return rcode;
                         }
                 }
@@ -1832,11 +1860,7 @@ static int run_pipe(struct pipe *pi)
                                 save_nofork_data(&G.nofork_save);
                                 debug_printf_exec(": run_nofork_applet '%s' '%s'...\n", argv_expanded[0], argv_expanded[1]);
                                 rcode = run_nofork_applet_prime(&G.nofork_save, a, argv_expanded);
-                                free(argv_expanded);
-                                restore_redirects(squirrel);
-                                debug_printf_exec("run_pipe return %d\n", rcode);
-                                IF_HAS_KEYWORDS(if (pi->pi_inverted) rcode = !rcode;)
-                                return rcode;
+                                goto clean_up_and_ret;
                         }
                 }
 #endif
@@ -1856,14 +1880,15 @@ static int run_pipe(struct pipe *pi)
 
         for (i = 0; i < pi->num_cmds; i++) {
 #if !BB_MMU
-                char **ptrs2free = NULL;
+                /* Avoid confusion WHAT is volatile. Pointer is volatile,
+                 * not the stuff it points to. */
+                typedef char **ppchar_t;
+                volatile ppchar_t shared_across_vfork;
 #endif
+
                 command = &(pi->cmds[i]);
                 if (command->argv) {
                         debug_printf_exec(": pipe member '%s' '%s'...\n", command->argv[0], command->argv[1]);
-#if !BB_MMU
-                        ptrs2free = alloc_ptrs(command->argv);
-#endif
                 } else
                         debug_printf_exec(": pipe member with no argv\n");
 
@@ -1873,6 +1898,9 @@ static int run_pipe(struct pipe *pi)
                 if ((i + 1) < pi->num_cmds)
                         xpipe(pipefds);
 
+#if !BB_MMU
+                shared_across_vfork = ptrs2free;
+#endif
                 command->pid = BB_MMU ? fork() : vfork();
                 if (!command->pid) { /* child */
                         if (ENABLE_HUSH_JOB)
@@ -1906,13 +1934,19 @@ static int run_pipe(struct pipe *pi)
                         set_jobctrl_sighandler(SIG_DFL);
                         set_misc_sighandler(SIG_DFL);
                         signal(SIGCHLD, SIG_DFL);
-                        pseudo_exec(ptrs2free, command, argv_expanded); /* does not return */
+/* comment how it sets env????
+for single_and_fg, it's already set yes? */
+                        pseudo_exec((char ***) &shared_across_vfork, command, argv_expanded);
+                        /* pseudo_exec() does not return */
                 }
-                free(argv_expanded);
-                argv_expanded = NULL;
+                /* parent */
 #if !BB_MMU
-                free_strings(ptrs2free);
+                ptrs2free = shared_across_vfork;
 #endif
+                free(argv_expanded);
+                argv_expanded = NULL;
+                free_strings_and_unsetenv(ptrs2free, 1);
+                ptrs2free = NULL;
                 if (command->pid < 0) { /* [v]fork failed */
                         /* Clearly indicate, was it fork or vfork */
                         bb_perror_msg(BB_MMU ? "fork" : "vfork");
@@ -4077,10 +4111,9 @@ static void setup_job_control(void)
 int hush_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 int hush_main(int argc, char **argv)
 {
-        static const char version_str[] ALIGN1 = "HUSH_VERSION="HUSH_VER_STR;
         static const struct variable const_shell_ver = {
                 .next = NULL,
-                .varstr = (char*)version_str,
+                .varstr = (char*)hush_version_str,
                 .max_len = 1, /* 0 can provoke free(name) */
                 .flg_export = 1,
                 .flg_read_only = 1,
@@ -4114,7 +4147,7 @@ int hush_main(int argc, char **argv)
                 }
                 e++;
         }
-        putenv((char *)version_str); /* reinstate HUSH_VERSION */
+        putenv((char *)hush_version_str); /* reinstate HUSH_VERSION */
 
 #if ENABLE_FEATURE_EDITING
         G.line_input_state = new_line_input_t(FOR_SHELL);
@@ -4338,10 +4371,10 @@ static int builtin_exec(char **argv)
                 return EXIT_SUCCESS; /* bash does this */
         {
 #if !BB_MMU
-                char **ptrs2free = alloc_ptrs(argv);
+                char **ptrs2free = NULL;
 #endif
 // FIXME: if exec fails, bash does NOT exit! We do...
-                pseudo_exec_argv(ptrs2free, argv + 1, 0, NULL);
+                pseudo_exec_argv(&ptrs2free, argv + 1, 0, NULL);
                 /* never returns */
         }
 }
diff --git a/shell/hush_test/hush-vars/var_leaks.right b/shell/hush_test/hush-vars/var_leaks.right
new file mode 100644
index 000000000..d86bac9de
--- /dev/null
+++ b/shell/hush_test/hush-vars/var_leaks.right
@@ -0,0 +1 @@
+OK
diff --git a/shell/hush_test/hush-vars/var_leaks.tests b/shell/hush_test/hush-vars/var_leaks.tests
new file mode 100755
index 000000000..27c8c6504
--- /dev/null
+++ b/shell/hush_test/hush-vars/var_leaks.tests
@@ -0,0 +1,14 @@
+# external program
+a=b /bin/true
+env | grep ^a=
+
+# builtin
+a=b true
+env | grep ^a=
+
+# exec with redirection only
+# in bash, this leaks!
+a=b exec 1>&1
+env | grep ^a=
+
+echo OK
diff --git a/shell/hush_test/hush-z_slow/leak_var.tests b/shell/hush_test/hush-z_slow/leak_var.tests
index 388d6a734..b3e13e308 100755
--- a/shell/hush_test/hush-z_slow/leak_var.tests
+++ b/shell/hush_test/hush-z_slow/leak_var.tests
@@ -42,6 +42,53 @@ while test $i != X; do
 done
 end=`ps -o pid,vsz | grep "^ *$pid "`
 
+# Warm up again (I do need it on my machine)
+beg=`ps -o pid,vsz | grep "^ *$pid "`
+i=1
+while test $i != X; do
+    unset t
+    t=111111111111111111111111111111111111111111111111111111111111111111111111
+    export t
+    unset t
+    t=111111111111111111111111111111111111111111111111111111111111111111111111
+    export t
+    unset t
+    t=111111111111111111111111111111111111111111111111111111111111111111111111
+    export t
+    unset t
+    t=111111111111111111111111111111111111111111111111111111111111111111111111
+    export t
+    unset t
+    t=111111111111111111111111111111111111111111111111111111111111111111111111
+    export t
+    i=1$i
+    if test $i = 1111111111111111111111111111111111111111111111; then i=2; fi
+    if test $i = 1111111111111111111111111111111111111111111112; then i=3; fi
+    if test $i = 1111111111111111111111111111111111111111111113; then i=4; fi
+    if test $i = 1111111111111111111111111111111111111111111114; then i=5; fi
+    if test $i = 1111111111111111111111111111111111111111111115; then i=6; fi
+    if test $i = 1111111111111111111111111111111111111111111116; then i=7; fi
+    if test $i = 1111111111111111111111111111111111111111111117; then i=8; fi
+    if test $i = 1111111111111111111111111111111111111111111118; then i=9; fi
+    if test $i = 1111111111111111111111111111111111111111111119; then i=a; fi
+    if test $i = 111111111111111111111111111111111111111111111a; then i=b; fi
+    if test $i = 111111111111111111111111111111111111111111111b; then i=c; fi
+    if test $i = 111111111111111111111111111111111111111111111c; then i=d; fi
+    if test $i = 111111111111111111111111111111111111111111111d; then i=e; fi
+    if test $i = 111111111111111111111111111111111111111111111e; then i=f; fi
+    if test $i = 111111111111111111111111111111111111111111111f; then i=g; fi
+    if test $i = 111111111111111111111111111111111111111111111g; then i=h; fi
+    if test $i = 111111111111111111111111111111111111111111111h; then i=i; fi
+    if test $i = 111111111111111111111111111111111111111111111i; then i=j; fi
+    if test $i = 111111111111111111111111111111111111111111111j; then i=X; fi
+done
+end=`ps -o pid,vsz | grep "^ *$pid "`
+if test "$beg" != "$end"; then
+    true echo "vsz grows: $beg -> $end"
+else
+    true echo "vsz does not grow"
+fi
+
 echo "Measuring memory leak..."
 beg=`ps -o pid,vsz | grep "^ *$pid "`
 i=1
diff --git a/shell/hush_test/hush-z_slow/leak_var2.right b/shell/hush_test/hush-z_slow/leak_var2.right
new file mode 100644
index 000000000..7bccc1eef
--- /dev/null
+++ b/shell/hush_test/hush-z_slow/leak_var2.right
@@ -0,0 +1,2 @@
+Measuring memory leak...
+vsz does not grow
diff --git a/shell/hush_test/hush-z_slow/leak_var2.tests b/shell/hush_test/hush-z_slow/leak_var2.tests
new file mode 100755
index 000000000..09f247552
--- /dev/null
+++ b/shell/hush_test/hush-z_slow/leak_var2.tests
@@ -0,0 +1,63 @@
+pid=$$
+
+t=1
+export t
+
+# Warm up
+beg=`ps -o pid,vsz | grep "^ *$pid "`
+i=1
+while test $i != X; do
+    t=111111111111111111111111111111111111111111111111111111111111111111111110$i
+    t=111111111111111111111111111111111111111111111111111111111111111111111111$i true
+    t=111111111111111111111111111111111111111111111111111111111111111111111112$i /bin/true
+    t=111111111111111111111111111111111111111111111111111111111111111111111113$i exec 1>&1
+    i=1$i
+    if test $i = 1111111111111111111111111111111111111111111111; then i=2; fi
+    if test $i = 1111111111111111111111111111111111111111111112; then i=3; fi
+    if test $i = 1111111111111111111111111111111111111111111113; then i=4; fi
+    if test $i = 1111111111111111111111111111111111111111111114; then i=X; fi
+done
+end=`ps -o pid,vsz | grep "^ *$pid "`
+
+# Warm up again (I do need it on my machine)
+beg=`ps -o pid,vsz | grep "^ *$pid "`
+i=1
+while test $i != X; do
+    t=111111111111111111111111111111111111111111111111111111111111111111111110$i
+    t=111111111111111111111111111111111111111111111111111111111111111111111111$i true
+    t=111111111111111111111111111111111111111111111111111111111111111111111112$i /bin/true
+    t=111111111111111111111111111111111111111111111111111111111111111111111113$i exec 1>&1
+    i=1$i
+    if test $i = 1111111111111111111111111111111111111111111111; then i=2; fi
+    if test $i = 1111111111111111111111111111111111111111111112; then i=3; fi
+    if test $i = 1111111111111111111111111111111111111111111113; then i=4; fi
+    if test $i = 1111111111111111111111111111111111111111111114; then i=X; fi
+done
+end=`ps -o pid,vsz | grep "^ *$pid "`
+if test "$beg" != "$end"; then
+    true echo "vsz grows: $beg -> $end"
+else
+    true echo "vsz does not grow"
+fi
+
+echo "Measuring memory leak..."
+beg=`ps -o pid,vsz | grep "^ *$pid "`
+i=1
+while test $i != X; do
+    t=111111111111111111111111111111111111111111111111111111111111111111111110$i
+    t=111111111111111111111111111111111111111111111111111111111111111111111111$i true
+    t=111111111111111111111111111111111111111111111111111111111111111111111112$i /bin/true
+    t=111111111111111111111111111111111111111111111111111111111111111111111113$i exec 1>&1
+    i=1$i
+    if test $i = 1111111111111111111111111111111111111111111111; then i=2; fi
+    if test $i = 1111111111111111111111111111111111111111111112; then i=3; fi
+    if test $i = 1111111111111111111111111111111111111111111113; then i=4; fi
+    if test $i = 1111111111111111111111111111111111111111111114; then i=X; fi
+done
+end=`ps -o pid,vsz | grep "^ *$pid "`
+
+if test "$beg" != "$end"; then
+    echo "vsz grows: $beg -> $end"
+else
+    echo "vsz does not grow"
+fi