hush: move towards more correct variable expansion
hush: fix a few cases in FOR v IN ... construct
unfortunately, code growth is big - ~600 bytes
diff --git a/shell/hush.c b/shell/hush.c
index dfb8191..803970b 100644
--- a/shell/hush.c
+++ b/shell/hush.c
@@ -85,13 +85,14 @@
/* If you comment out one of these below, it will be #defined later
* to perform debug printfs to stderr: */
-#define debug_printf(...) do {} while (0)
+#define debug_printf(...) do {} while (0)
/* Finer-grained debug switches */
-#define debug_printf_parse(...) do {} while (0)
-#define debug_print_tree(a, b) do {} while (0)
-#define debug_printf_exec(...) do {} while (0)
-#define debug_printf_jobs(...) do {} while (0)
-#define debug_printf_clean(...) do {} while (0)
+#define debug_printf_parse(...) do {} while (0)
+#define debug_print_tree(a, b) do {} while (0)
+#define debug_printf_exec(...) do {} while (0)
+#define debug_printf_jobs(...) do {} while (0)
+#define debug_printf_expand(...) do {} while (0)
+#define debug_printf_clean(...) do {} while (0)
#ifndef debug_printf
#define debug_printf(...) fprintf(stderr, __VA_ARGS__)
@@ -110,6 +111,11 @@
#define DEBUG_SHELL_JOBS 1
#endif
+#ifndef debug_printf_expand
+#define debug_printf_expand(...) fprintf(stderr, __VA_ARGS__)
+#define DEBUG_EXPAND 1
+#endif
+
#ifndef debug_printf_clean
/* broken, of course, but OK for testing */
static const char *indenter(int i)
@@ -229,6 +235,12 @@
int sp; /* number of SPECIAL_VAR_SYMBOL */
int type;
};
+// sp counting seems to be broken...
+/* argv vector may contain variable references (^Cvar^C, ^C0^C etc)
+ * and on execution these are substituted with their values.
+ * Substitution can make _several_ words out of one argv[n]!
+ * Example: argv[0]=='.^C*^C.' here: echo .$*.
+ */
struct pipe {
struct pipe *next;
@@ -430,7 +442,7 @@
int checkjobs_and_fg_shell(struct pipe* fg_pipe); /* never called */
#endif
/* local variable support */
-static char **make_list_in(char **inp, char *name);
+static char **do_variable_expansion(char **argv);
static char *insert_var_value(char *inp);
static const char *get_local_var(const char *var);
static int set_local_var(const char *s, int flg_export);
@@ -1265,10 +1277,8 @@
for (i = 0; i < 3; i++) {
fd = squirrel[i];
if (fd != -1) {
- /* No error checking. I sure wouldn't know what
- * to do with an error if I found one! */
- dup2(fd, i);
- close(fd);
+ /* We simply die on error */
+ xmove_fd(fd, i);
}
}
}
@@ -1916,9 +1926,9 @@
enum { level = 0 };
#endif
- char *save_name = NULL;
- char **list = NULL;
- char **save_list = NULL;
+ char *for_varname = NULL;
+ char **for_lcur = NULL;
+ char **for_list = NULL;
struct pipe *rpipe;
int flag_rep = 0;
int save_num_progs;
@@ -2018,30 +2028,29 @@
if (rmode == RES_ELIF && !if_code)
break;
if (rmode == RES_FOR && pi->num_progs) {
- if (!list) {
+ if (!for_lcur) {
/* if no variable values after "in" we skip "for" */
if (!pi->next->progs->argv)
continue;
/* create list of variable values */
- list = make_list_in(pi->next->progs->argv,
- pi->progs->argv[0]);
- save_list = list;
- save_name = pi->progs->argv[0];
+ for_list = do_variable_expansion(pi->next->progs->argv);
+ for_lcur = for_list;
+ for_varname = pi->progs->argv[0];
pi->progs->argv[0] = NULL;
flag_rep = 1;
}
- if (!*list) {
- free(pi->progs->argv[0]);
- free(save_list);
- list = NULL;
+ free(pi->progs->argv[0]);
+ if (!*for_lcur) {
+ free(for_list);
+ for_lcur = NULL;
flag_rep = 0;
- pi->progs->argv[0] = save_name;
+ pi->progs->argv[0] = for_varname;
pi->progs->glob_result.gl_pathv[0] = pi->progs->argv[0];
continue;
}
- /* insert new value from list for variable */
- free(pi->progs->argv[0]);
- pi->progs->argv[0] = *list++;
+ /* insert next value from for_lcur */
+ //vda: does it need escaping?
+ pi->progs->argv[0] = xasprintf("%s=%s", for_varname, *for_lcur++);
pi->progs->glob_result.gl_pathv[0] = pi->progs->argv[0];
}
if (rmode == RES_IN)
@@ -2288,50 +2297,267 @@
return gr;
}
-static char **make_list_in(char **inp, char *name)
-{
- int len, i;
-#if 0
- int name_len = strlen(name);
-#endif
- int n;
- char **list;
- char *p1, *p2, *p3;
- /* create list of variable values */
- list = xmalloc(sizeof(*list));
- n = 0;
- for (i = 0; inp[i]; i++) {
- p3 = insert_var_value(inp[i]);
- p1 = p3;
- while (*p1) {
- if (*p1 == ' ') {
- p1++;
- continue;
- }
- p2 = strchrnul(p1, ' ');
- len = p2 - p1;
- /* we use n + 2 in realloc for list, because we add
- * new element and then we will add NULL element */
- list = xrealloc(list, sizeof(*list) * (n + 2));
- list[n] = xasprintf("%s=%.*s", name, len, p1);
-#if 0 /* faster, but more code */
- list[n] = xmalloc(2 + name_len + len);
- strcpy(list[n], name);
- list[n][name_len] = '=';
- strncat(&(list[n][name_len + 1]), p1, len);
- list[n][name_len + len + 1] = '\0';
-#endif
- n++;
- p1 = p2;
- }
- if (p3 != inp[i])
- free(p3);
+/* do_variable_expansion() takes a list of strings, expands
+ * all variable references within and returns a pointer to
+ * a list of expanded strings, possibly with larger number
+ * of strings. (Think VAR="a b"; echo $VAR).
+ * This new list is allocated as a single malloc block.
+ * NULL-terminated list of char* pointers is at the beginning of it,
+ * followed by strings themself.
+ * Caller can deallocate entire list by single free(list). */
+
+/* Helpers first:
+ * count_XXX estimates, how large block do we need. It's okay
+ * to over-estimate sizes a bit, if it makes code simpler */
+static int count_ifs(const char *str)
+{
+ int cnt = 0;
+ debug_printf_expand("count_ifs('%s') ifs='%s'", str, ifs);
+ while (1) {
+ str += strcspn(str, ifs);
+ if (!*str) break;
+ str++; // str += strspn(str, ifs); ?
+ cnt++; // cnt += strspn(str, ifs); ?
}
+ debug_printf_expand(" return %d\n", cnt);
+ return cnt;
+}
+
+static void count_var_expansion_space(int *countp, int *lenp, char *arg)
+{
+ char first_ch;
+ int i;
+ int len = *lenp;
+ int count = *countp;
+ const char *val;
+ char *p;
+
+ while ((p = strchr(arg, SPECIAL_VAR_SYMBOL))) {
+ len += p - arg;
+ arg = ++p;
+ p = strchr(p, SPECIAL_VAR_SYMBOL);
+ first_ch = arg[0];
+
+ switch (first_ch & 0x7f) {
+ /* high bit in 1st_ch indicates that var is double-quoted */
+ case '$': /* pid */
+ case '!': /* bg pid */
+ case '?': /* exitcode */
+ case '#': /* argc */
+ len += sizeof(int)*3 + 1; /* enough for int */
+ break;
+ case '*':
+ case '@':
+ for (i = 1; i < global_argc; i++) {
+ len += strlen(global_argv[i]) + 1;
+ count++;
+ if (!(first_ch & 0x80))
+ count += count_ifs(global_argv[i]);
+ }
+ break;
+ default:
+ *p = '\0';
+ arg[0] = first_ch & 0x7f;
+ val = lookup_param(arg);
+ arg[0] = first_ch;
+ *p = SPECIAL_VAR_SYMBOL;
+
+ if (val) {
+ len += strlen(val) + 1;
+ if (!(first_ch & 0x80))
+ count += count_ifs(val);
+ }
+ }
+ arg = ++p;
+ }
+
+ len += strlen(arg) + 1;
+ count++;
+ *lenp = len;
+ *countp = count;
+}
+
+/* Store given string, finalizing the word and starting new one whenever
+ * we encounter ifs char(s). This is used for expanding variable values.
+ * End-of-string does NOT finalize word, because cases like echo -$VAR- */
+static int expand_on_ifs(char **list, int n, char **posp, const char *str)
+{
+ char *pos = *posp;
+ while (1) {
+ int word_len = strcspn(str, ifs);
+ if (word_len) {
+ memcpy(pos, str, word_len); /* store non-ifs chars */
+ pos += word_len;
+ str += word_len;
+ if (!*str) /* EOL - do not finalize word */
+ break;
+ *pos++ = '\0';
+ if (n) debug_printf_expand("expand_on_ifs finalized list[%d]=%p '%s' "
+ "strlen=%d next=%p pos=%p\n", n-1, list[n-1], list[n-1],
+ strlen(list[n-1]), list[n-1] + strlen(list[n-1]) + 1, pos);
+ list[n++] = pos;
+ }
+ if (!*str) break; /* EOL, not ifs char */
+ str += strspn(str, ifs); /* skip ifs chars */
+ }
+ *posp = pos;
+ return n;
+}
+
+/* Expand all variable references in given string, adding words to list[]
+ * at n, n+1,... positions. Return updated n (so that list[n] is next one
+ * to be filled). This routine is extremely tricky: has to deal with
+ * variables/parameters with whitespace, $* and $@, and constructs like
+ * 'echo -$*-'. If you play here, you must run testsuite afterwards! */
+/* NB: support for double-quoted expansion is not used yet (we never set
+ * magic bit 0x80 elsewhere...) */
+/* NB: another bug is that we cannot detect empty strings yet:
+ * "" or $empty"" expands to zero words, has to expand to empty word */
+static int expand_vars_to_list(char **list, int n, char **posp, char *arg)
+{
+ char first_ch, ored_ch;
+ const char *val;
+ char *p;
+ char *pos = *posp;
+
+ ored_ch = 0;
+
+ if (n) debug_printf_expand("expand_vars_to_list finalized list[%d]=%p '%s' "
+ "strlen=%d next=%p pos=%p\n", n-1, list[n-1], list[n-1],
+ strlen(list[n-1]), list[n-1] + strlen(list[n-1]) + 1, pos);
+ list[n++] = pos;
+
+ while ((p = strchr(arg, SPECIAL_VAR_SYMBOL))) {
+ memcpy(pos, arg, p - arg);
+ pos += (p - arg);
+ arg = ++p;
+ p = strchr(p, SPECIAL_VAR_SYMBOL);
+
+ first_ch = arg[0];
+ ored_ch |= first_ch;
+ val = NULL;
+ switch (first_ch & 0x7f) {
+ /* Highest bit in first_ch indicates that var is double-quoted */
+ case '$': /* pid */
+ /* FIXME: (echo $$) should still print pid of main shell */
+ val = utoa(getpid());
+ break;
+ case '!': /* bg pid */
+ val = last_bg_pid ? utoa(last_bg_pid) : (char*)"";
+ break;
+ case '?': /* exitcode */
+ val = utoa(last_return_code);
+ break;
+ case '#': /* argc */
+ val = utoa(global_argc ? global_argc-1 : 0);
+ break;
+ case '*':
+ case '@':
+ if (!(first_ch & 0x80)) { /* unquoted $* or $@ */
+ int i = 1;
+ while (i < global_argc) {
+ n = expand_on_ifs(list, n, &pos, global_argv[i]);
+ debug_printf_expand("expand_vars_to_list: argv %d (last %d)\n", i, global_argc-1);
+ if (global_argv[i++][0] && i < global_argc) {
+ /* this argv[] is not empty and not last:
+ * put terminating NUL, start new word */
+ *pos++ = '\0';
+ if (n) debug_printf_expand("expand_vars_to_list 2 finalized list[%d]=%p '%s' "
+ "strlen=%d next=%p pos=%p\n", n-1, list[n-1], list[n-1],
+ strlen(list[n-1]), list[n-1] + strlen(list[n-1]) + 1, pos);
+ list[n++] = pos;
+ }
+ }
+ } else if (first_ch == ('@'|0x80)) { /* quoted $@ */
+ /* TODO */
+ } else { /* quoted $* */
+ /* TODO */
+ }
+ break;
+ default:
+ *p = '\0';
+ arg[0] = first_ch & 0x7f;
+ val = lookup_param(arg);
+ arg[0] = first_ch;
+ *p = SPECIAL_VAR_SYMBOL;
+ if (!(first_ch & 0x80)) { /* unquoted var */
+ if (val) {
+ n = expand_on_ifs(list, n, &pos, val);
+ val = NULL;
+ }
+ }
+ }
+ if (val) {
+ strcpy(pos, val);
+ pos += strlen(val);
+ }
+ arg = ++p;
+ }
+ debug_printf_expand("expand_vars_to_list adding tail '%s' at %p\n", arg, pos);
+ strcpy(pos, arg);
+ pos += strlen(arg) + 1;
+ if (pos == list[n-1] + 1) { /* expansion is empty */
+ if (!(ored_ch & 0x80)) { /* all vars were not quoted... */
+ debug_printf_expand("expand_vars_to_list list[%d] empty, going back\n", n);
+ pos--;
+ n--;
+ }
+ }
+
+ *posp = pos;
+ return n;
+}
+
+static char **do_variable_expansion(char **argv)
+{
+ int n;
+ int count = 1;
+ int len = 0;
+ char *pos, **v, **list;
+
+ v = argv;
+ if (!*v) debug_printf_expand("count_var_expansion_space: "
+ "argv[0]=NULL count=%d len=%d alloc_space=%d\n",
+ count, len, sizeof(char*) * count + len);
+ while (*v) {
+ count_var_expansion_space(&count, &len, *v);
+ debug_printf_expand("count_var_expansion_space: "
+ "'%s' count=%d len=%d alloc_space=%d\n",
+ *v, count, len, sizeof(char*) * count + len);
+ v++;
+ }
+ len += sizeof(char*) * count; /* total to alloc */
+ list = xmalloc(len);
+ pos = (char*)(list + count);
+ debug_printf_expand("list=%p, list[0] should be %p\n", list, pos);
+ n = 0;
+ v = argv;
+ while (*v)
+ n = expand_vars_to_list(list, n, &pos, *v++);
+
+ if(n) debug_printf_expand("finalized list[%d]=%p '%s' "
+ "strlen=%d next=%p pos=%p\n", n-1, list[n-1], list[n-1],
+ strlen(list[n-1]), list[n-1] + strlen(list[n-1]) + 1, pos);
list[n] = NULL;
+
+#ifdef DEBUG_EXPAND
+ {
+ int m = 0;
+ while (m <= n) {
+ debug_printf_expand("list[%d]=%p '%s'\n", m, list[m], list[m]);
+ m++;
+ }
+ debug_printf_expand("used_space=%d\n", pos - (char*)list);
+ }
+#endif
+ /* To be removed / made conditional later. */
+ if (pos - (char*)list > len)
+ bb_error_msg_and_die("BUG in varexp");
return list;
}
+
static char *insert_var_value(char *inp)
{
int res_str_len = 0;
@@ -2404,6 +2630,21 @@
return (res_str == NULL) ? inp : res_str;
}
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
/* This is used to get/check local shell variables */
static const char *get_local_var(const char *s)
{
@@ -2986,7 +3227,7 @@
}
/* Make new string for parser */
-static char* make_string(char ** inp)
+static char* make_string(char **inp)
{
char *p;
char *str = NULL;
