hush: fix "true | exit 3; echo $?" bug
This commit is contained in:
Denis Vlasenko
parent
f2fffd0014
commit
e725bfe6e0
13
shell/README
13
shell/README
@ -1,5 +1,18 @@
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Various bits of what is known about busybox shells, in no particular order.
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2007-05-03
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hush: update on "sleep 1 | exit 3; echo $?" bug.
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parse_stream_outer() repeatedly calls parse_stream().
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parse_stream() is now fixed to stop on ';' in this example,
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fixing it (parse_stream_outer() will call parse_stream() 1st time,
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execute the parse tree, call parse_stream() 2nd time and execute the tree).
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But it's not the end of story.
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In more complex situations we _must_ parse way farther before executing.
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Example #2: "{ sleep 1 | exit 3; echo $?; ...few_lines... } >file".
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Because of redirection, we cannot execute 1st pipe before we parse it all.
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We probably need to learn to store $var expressions in parse tree.
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Debug printing of parse tree would be nice too.
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2007-04-28
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hush: Ctrl-C and Ctrl-Z for single NOFORK commands are working.
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Memory and other resource leaks (opendir) are not addressed
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138
shell/hush.c
138
shell/hush.c
@ -89,6 +89,7 @@
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/* Finer-grained debug switch */
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#define debug_printf_jobs(...) do {} while (0)
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#define debug_printf_exec(...) do {} while (0)
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#define debug_printf_parse(...) do {} while (0)
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#ifndef debug_printf
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@ -111,6 +112,10 @@ static const char *indenter(int i)
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#define debug_printf_exec(...) fprintf(stderr, __VA_ARGS__)
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#endif
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#ifndef debug_printf_parse
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#define debug_printf_parse(...) fprintf(stderr, __VA_ARGS__)
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#endif
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#if !ENABLE_HUSH_INTERACTIVE
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#undef ENABLE_FEATURE_EDITING
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@ -259,8 +264,14 @@ static int last_return_code;
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extern char **environ; /* This is in <unistd.h>, but protected with __USE_GNU */
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/* "globals" within this file */
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static const char *ifs;
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enum {
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MAP_ORDINARY = 0,
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MAP_FLOWTROUGH_IF_QUOTED = 1,
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MAP_IFS_IF_UNQUOTED = 2, /* flow through if quoted too */
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MAP_NEVER_FLOWTROUGH = 3,
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};
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static unsigned char map[256];
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static const char *ifs;
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static int fake_mode;
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static struct close_me *close_me_head;
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static const char *cwd;
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@ -390,13 +401,13 @@ static int done_pipe(struct p_context *ctx, pipe_style type);
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/* primary string parsing: */
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static int redirect_dup_num(struct in_str *input);
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static int redirect_opt_num(o_string *o);
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static int process_command_subs(o_string *dest, struct p_context *ctx, struct in_str *input, int subst_end);
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static int process_command_subs(o_string *dest, struct p_context *ctx, struct in_str *input, const char *subst_end);
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static int parse_group(o_string *dest, struct p_context *ctx, struct in_str *input, int ch);
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static const char *lookup_param(const char *src);
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static char *make_string(char **inp);
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static int handle_dollar(o_string *dest, struct p_context *ctx, struct in_str *input);
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static int parse_string(o_string *dest, struct p_context *ctx, const char *src);
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static int parse_stream(o_string *dest, struct p_context *ctx, struct in_str *input0, int end_trigger);
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static int parse_stream(o_string *dest, struct p_context *ctx, struct in_str *input0, const char *end_trigger);
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/* setup: */
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static int parse_stream_outer(struct in_str *inp, int flag);
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static int parse_string_outer(const char *s, int flag);
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@ -1977,8 +1988,9 @@ static int run_list_real(struct pipe *pi)
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{
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rcode = checkjobs(pi);
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}
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debug_printf("checkjobs returned %d\n", rcode);
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debug_printf_exec("checkjobs returned %d\n", rcode);
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}
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debug_printf_exec("setting last_return_code=%d\n", rcode);
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last_return_code = rcode;
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pi->num_progs = save_num_progs; /* restore number of programs */
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if (rmode == RES_IF || rmode == RES_ELIF)
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@ -2519,7 +2531,7 @@ static int reserved_word(o_string *dest, struct p_context *ctx)
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return 0;
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}
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/* normal return is 0.
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/* Normal return is 0.
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* Syntax or xglob errors return 1. */
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static int done_word(o_string *dest, struct p_context *ctx)
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{
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@ -2527,9 +2539,9 @@ static int done_word(o_string *dest, struct p_context *ctx)
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glob_t *glob_target;
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int gr, flags = 0;
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debug_printf("done_word: %s %p\n", dest->data, child);
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debug_printf_parse("done_word: '%s' %p\n", dest->data, child);
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if (dest->length == 0 && !dest->nonnull) {
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debug_printf(" true null, ignored\n");
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debug_printf_parse("done_word return 0: true null, ignored\n");
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return 0;
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}
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if (ctx->pending_redirect) {
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@ -2537,24 +2549,31 @@ static int done_word(o_string *dest, struct p_context *ctx)
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} else {
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if (child->group) {
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syntax();
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return 1; /* syntax error, groups and arglists don't mix */
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debug_printf_parse("done_word return 1: syntax error, groups and arglists don't mix\n");
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return 1;
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}
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if (!child->argv && (ctx->type & FLAG_PARSE_SEMICOLON)) {
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debug_printf("checking %s for reserved-ness\n", dest->data);
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if (reserved_word(dest, ctx))
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debug_printf_parse(": checking %s for reserved-ness\n", dest->data);
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if (reserved_word(dest, ctx)) {
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debug_printf_parse("done_word return %d\n", (ctx->w == RES_SNTX));
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return (ctx->w == RES_SNTX);
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}
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}
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glob_target = &child->glob_result;
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if (child->argv) flags |= GLOB_APPEND;
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}
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gr = xglob(dest, flags, glob_target);
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if (gr != 0) return 1;
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if (gr != 0) {
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debug_printf_parse("done_word return 1: xglob returned %d\n", gr);
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return 1;
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}
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b_reset(dest);
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if (ctx->pending_redirect) {
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ctx->pending_redirect = NULL;
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if (glob_target->gl_pathc != 1) {
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bb_error_msg("ambiguous redirect");
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debug_printf_parse("done_word return 1: ambiguous redirect\n");
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return 1;
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}
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} else {
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@ -2564,6 +2583,7 @@ static int done_word(o_string *dest, struct p_context *ctx)
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done_word(dest, ctx);
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done_pipe(ctx, PIPE_SEQ);
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}
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debug_printf_parse("done_word return 0\n");
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return 0;
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}
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@ -2614,7 +2634,7 @@ static int done_pipe(struct p_context *ctx, pipe_style type)
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{
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struct pipe *new_p;
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done_command(ctx); /* implicit closure of previous command */
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debug_printf("done_pipe, type %d\n", type);
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debug_printf_parse("done_pipe, type %d\n", type);
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ctx->pipe->followup = type;
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ctx->pipe->r_mode = ctx->w;
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new_p = new_pipe();
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@ -2710,7 +2730,8 @@ static FILE *generate_stream_from_list(struct pipe *head)
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/* this version hacked for testing purposes */
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/* return code is exit status of the process that is run. */
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static int process_command_subs(o_string *dest, struct p_context *ctx, struct in_str *input, int subst_end)
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static int process_command_subs(o_string *dest, struct p_context *ctx,
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struct in_str *input, const char *subst_end)
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{
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int retcode;
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o_string result = NULL_O_STRING;
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@ -2732,7 +2753,7 @@ static int process_command_subs(o_string *dest, struct p_context *ctx, struct in
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setup_file_in_str(&pipe_str, p);
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/* now send results of command back into original context */
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retcode = parse_stream(dest, ctx, &pipe_str, '\0');
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retcode = parse_stream(dest, ctx, &pipe_str, NULL);
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/* XXX In case of a syntax error, should we try to kill the child?
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* That would be tough to do right, so just read until EOF. */
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if (retcode == 1) {
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@ -2757,21 +2778,25 @@ static int process_command_subs(o_string *dest, struct p_context *ctx, struct in
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static int parse_group(o_string *dest, struct p_context *ctx,
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struct in_str *input, int ch)
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{
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int rcode, endch = 0;
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int rcode;
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const char *endch = NULL;
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struct p_context sub;
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struct child_prog *child = ctx->child;
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debug_printf_parse("parse_group entered\n");
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if (child->argv) {
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syntax();
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return 1; /* syntax error, groups and arglists don't mix */
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debug_printf_parse("parse_group return 1: syntax error, groups and arglists don't mix\n");
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return 1;
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}
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initialize_context(&sub);
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switch (ch) {
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case '(':
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endch = ')';
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endch = ")";
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child->subshell = 1;
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break;
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case '{':
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endch = '}';
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endch = "}";
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break;
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default:
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syntax(); /* really logic error */
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@ -2780,6 +2805,8 @@ static int parse_group(o_string *dest, struct p_context *ctx,
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done_word(dest, &sub); /* finish off the final word in the subcontext */
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done_pipe(&sub, PIPE_SEQ); /* and the final command there, too */
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child->group = sub.list_head;
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debug_printf_parse("parse_group return %d\n", rcode);
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return rcode;
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/* child remains "open", available for possible redirects */
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}
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@ -2880,7 +2907,7 @@ static int handle_dollar(o_string *dest, struct p_context *ctx, struct in_str *i
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break;
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case '(':
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b_getch(input);
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process_command_subs(dest, ctx, input, ')');
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process_command_subs(dest, ctx, input, ")");
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break;
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case '*':
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sep[0] = ifs[0];
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@ -2913,12 +2940,12 @@ static int parse_string(o_string *dest, struct p_context *ctx, const char *src)
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{
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struct in_str foo;
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setup_string_in_str(&foo, src);
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return parse_stream(dest, ctx, &foo, '\0');
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return parse_stream(dest, ctx, &foo, NULL);
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}
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/* return code is 0 for normal exit, 1 for syntax error */
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static int parse_stream(o_string *dest, struct p_context *ctx,
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struct in_str *input, int end_trigger)
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struct in_str *input, const char *end_trigger)
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{
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int ch, m;
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int redir_fd;
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@ -2929,30 +2956,38 @@ static int parse_stream(o_string *dest, struct p_context *ctx,
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* A single-quote triggers a bypass of the main loop until its mate is
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* found. When recursing, quote state is passed in via dest->quote. */
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debug_printf("parse_stream, end_trigger=%d\n", end_trigger);
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debug_printf_parse("parse_stream entered, end_trigger='%s'\n", end_trigger);
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while ((ch = b_getch(input)) != EOF) {
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m = map[ch];
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next = (ch == '\n') ? 0 : b_peek(input);
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debug_printf("parse_stream: ch=%c (%d) m=%d quote=%d\n",
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debug_printf_parse(": ch=%c (%d) m=%d quote=%d\n",
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ch, ch, m, dest->quote);
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if (m == 0 || ((m == 1 || m == 2) && dest->quote)) {
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if (m == MAP_ORDINARY
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|| (m != MAP_NEVER_FLOWTROUGH && dest->quote)
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) {
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b_addqchr(dest, ch, dest->quote);
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continue;
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}
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if (m == 2) { /* unquoted IFS */
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if (m == MAP_IFS_IF_UNQUOTED) {
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if (done_word(dest, ctx)) {
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debug_printf_parse("parse_stream return 1\n");
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return 1;
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}
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/* If we aren't performing a substitution, treat a newline as a
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* command separator. */
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if (end_trigger != '\0' && ch == '\n')
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/* If we aren't performing a substitution, treat
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* a newline as a command separator.
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* [why we don't handle it exactly like ';'? --vda] */
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if (end_trigger && ch == '\n') {
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done_pipe(ctx, PIPE_SEQ);
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}
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if (ch == end_trigger && !dest->quote && ctx->w == RES_NONE) {
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debug_printf("leaving parse_stream (triggered)\n");
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}
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if ((end_trigger && strchr(end_trigger, ch))
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&& !dest->quote && ctx->w == RES_NONE
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) {
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debug_printf_parse("parse_stream return 0\n");
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return 0;
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}
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if (m == 2)
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if (m == MAP_IFS_IF_UNQUOTED)
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continue;
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switch (ch) {
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case '#':
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@ -2970,13 +3005,17 @@ static int parse_stream(o_string *dest, struct p_context *ctx,
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case '\\':
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if (next == EOF) {
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syntax();
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debug_printf_parse("parse_stream return 1\n");
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return 1;
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}
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b_addqchr(dest, '\\', dest->quote);
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b_addqchr(dest, b_getch(input), dest->quote);
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break;
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case '$':
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if (handle_dollar(dest, ctx, input) != 0) return 1;
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if (handle_dollar(dest, ctx, input) != 0) {
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debug_printf_parse("parse_stream return 1: handle_dollar returned non-0\n");
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return 1;
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}
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break;
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case '\'':
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dest->nonnull = 1;
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@ -2988,6 +3027,7 @@ static int parse_stream(o_string *dest, struct p_context *ctx,
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}
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if (ch == EOF) {
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syntax();
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debug_printf_parse("parse_stream return 1\n");
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return 1;
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}
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break;
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@ -2996,7 +3036,7 @@ static int parse_stream(o_string *dest, struct p_context *ctx,
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dest->quote = !dest->quote;
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break;
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case '`':
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process_command_subs(dest, ctx, input, '`');
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process_command_subs(dest, ctx, input, "`");
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break;
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case '>':
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redir_fd = redirect_opt_num(dest);
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@ -3007,6 +3047,7 @@ static int parse_stream(o_string *dest, struct p_context *ctx,
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b_getch(input);
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} else if (next == '(') {
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syntax(); /* until we support >(list) Process Substitution */
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debug_printf_parse("parse_stream return 1: >(process) not supported\n");
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return 1;
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}
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setup_redirect(ctx, redir_fd, redir_style, input);
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@ -3023,6 +3064,7 @@ static int parse_stream(o_string *dest, struct p_context *ctx,
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b_getch(input);
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} else if (next == '(') {
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syntax(); /* until we support <(list) Process Substitution */
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debug_printf_parse("parse_stream return 1: <(process) not supported\n");
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return 1;
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}
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setup_redirect(ctx, redir_fd, redir_style, input);
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@ -3054,28 +3096,32 @@ static int parse_stream(o_string *dest, struct p_context *ctx,
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break;
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case '(':
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case '{':
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if (parse_group(dest, ctx, input, ch) != 0)
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if (parse_group(dest, ctx, input, ch) != 0) {
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debug_printf_parse("parse_stream return 1: parse_group returned non-0\n");
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return 1;
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}
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break;
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case ')':
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case '}':
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syntax(); /* Proper use of this character caught by end_trigger */
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syntax(); /* Proper use of this character is caught by end_trigger */
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debug_printf_parse("parse_stream return 1: unexpected '}'\n");
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return 1;
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default:
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syntax(); /* this is really an internal logic error */
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debug_printf_parse("parse_stream return 1: internal logic error\n");
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return 1;
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}
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}
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/* complain if quote? No, maybe we just finished a command substitution
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/* Complain if quote? No, maybe we just finished a command substitution
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* that was quoted. Example:
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* $ echo "`cat foo` plus more"
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* and we just got the EOF generated by the subshell that ran "cat foo"
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* The only real complaint is if we got an EOF when end_trigger != '\0',
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* The only real complaint is if we got an EOF when end_trigger != NULL,
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* that is, we were really supposed to get end_trigger, and never got
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* one before the EOF. Can't use the standard "syntax error" return code,
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* so that parse_stream_outer can distinguish the EOF and exit smoothly. */
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debug_printf("leaving parse_stream (EOF)\n");
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if (end_trigger != '\0')
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debug_printf_parse("parse_stream return -%d\n", end_trigger != NULL);
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if (end_trigger)
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return -1;
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return 0;
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}
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@ -3097,17 +3143,17 @@ static void update_ifs_map(void)
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* The map[] array only really needs two bits each, and on most machines
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* that would be faster because of the reduced L1 cache footprint.
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*/
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memset(map, 0, sizeof(map)); /* most characters flow through always */
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mapset("\\$'\"`", 3); /* never flow through */
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mapset("<>;&|(){}#", 1); /* flow through if quoted */
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mapset(ifs, 2); /* also flow through if quoted */
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memset(map, MAP_ORDINARY, sizeof(map)); /* most chars flow through always */
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mapset("\\$'\"`", MAP_NEVER_FLOWTROUGH);
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mapset("<>;&|(){}#", MAP_FLOWTROUGH_IF_QUOTED);
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mapset(ifs, MAP_IFS_IF_UNQUOTED); /* also flow through if quoted */
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}
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/* most recursion does not come through here, the exception is
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* from builtin_source() */
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static int parse_stream_outer(struct in_str *inp, int flag)
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{
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// FIXME: 'true | exit 3; echo $?' is parsed as a whole,
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// FIXME: '{ true | exit 3; echo $? }' is parsed as a whole,
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// as a result $? is replaced by 0, not 3!
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// Need to stop & execute stuff at ';', not parse till EOL!
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||||
@ -3119,11 +3165,11 @@ static int parse_stream_outer(struct in_str *inp, int flag)
|
||||
initialize_context(&ctx);
|
||||
update_ifs_map();
|
||||
if (!(flag & FLAG_PARSE_SEMICOLON) || (flag & FLAG_REPARSING))
|
||||
mapset(";$&|", 0);
|
||||
mapset(";$&|", MAP_ORDINARY);
|
||||
#if ENABLE_HUSH_INTERACTIVE
|
||||
inp->promptmode = 1;
|
||||
#endif
|
||||
rcode = parse_stream(&temp, &ctx, inp, '\n');
|
||||
rcode = parse_stream(&temp, &ctx, inp, ";\n");
|
||||
if (rcode != 1 && ctx.old_flag != 0) {
|
||||
syntax();
|
||||
}
|
||||
|
||||
Loading…
Reference in New Issue
Block a user