diff options
| -rw-r--r-- | shell/README | 13 | ||||
| -rw-r--r-- | shell/hush.c | 138 |
2 files changed, 105 insertions, 46 deletions
diff --git a/shell/README b/shell/README index 40447cacb..989587a4f 100644 --- a/shell/README +++ b/shell/README @@ -1,5 +1,18 @@ Various bits of what is known about busybox shells, in no particular order. +2007-05-03 +hush: update on "sleep 1 | exit 3; echo $?" bug. +parse_stream_outer() repeatedly calls parse_stream(). +parse_stream() is now fixed to stop on ';' in this example, +fixing it (parse_stream_outer() will call parse_stream() 1st time, +execute the parse tree, call parse_stream() 2nd time and execute the tree). +But it's not the end of story. +In more complex situations we _must_ parse way farther before executing. +Example #2: "{ sleep 1 | exit 3; echo $?; ...few_lines... } >file". +Because of redirection, we cannot execute 1st pipe before we parse it all. +We probably need to learn to store $var expressions in parse tree. +Debug printing of parse tree would be nice too. + 2007-04-28 hush: Ctrl-C and Ctrl-Z for single NOFORK commands are working. Memory and other resource leaks (opendir) are not addressed diff --git a/shell/hush.c b/shell/hush.c index f3be78547..4d5e41244 100644 --- a/shell/hush.c +++ b/shell/hush.c @@ -89,6 +89,7 @@ /* Finer-grained debug switch */ #define debug_printf_jobs(...) do {} while (0) #define debug_printf_exec(...) do {} while (0) +#define debug_printf_parse(...) do {} while (0) #ifndef debug_printf @@ -111,6 +112,10 @@ static const char *indenter(int i) #define debug_printf_exec(...) fprintf(stderr, __VA_ARGS__) #endif +#ifndef debug_printf_parse +#define debug_printf_parse(...) fprintf(stderr, __VA_ARGS__) +#endif + #if !ENABLE_HUSH_INTERACTIVE #undef ENABLE_FEATURE_EDITING @@ -259,8 +264,14 @@ static int last_return_code; extern char **environ; /* This is in <unistd.h>, but protected with __USE_GNU */ /* "globals" within this file */ -static const char *ifs; +enum { + MAP_ORDINARY = 0, + MAP_FLOWTROUGH_IF_QUOTED = 1, + MAP_IFS_IF_UNQUOTED = 2, /* flow through if quoted too */ + MAP_NEVER_FLOWTROUGH = 3, +}; static unsigned char map[256]; +static const char *ifs; static int fake_mode; static struct close_me *close_me_head; static const char *cwd; @@ -390,13 +401,13 @@ static int done_pipe(struct p_context *ctx, pipe_style type); /* primary string parsing: */ static int redirect_dup_num(struct in_str *input); static int redirect_opt_num(o_string *o); -static int process_command_subs(o_string *dest, struct p_context *ctx, struct in_str *input, int subst_end); +static int process_command_subs(o_string *dest, struct p_context *ctx, struct in_str *input, const char *subst_end); static int parse_group(o_string *dest, struct p_context *ctx, struct in_str *input, int ch); static const char *lookup_param(const char *src); static char *make_string(char **inp); static int handle_dollar(o_string *dest, struct p_context *ctx, struct in_str *input); static int parse_string(o_string *dest, struct p_context *ctx, const char *src); -static int parse_stream(o_string *dest, struct p_context *ctx, struct in_str *input0, int end_trigger); +static int parse_stream(o_string *dest, struct p_context *ctx, struct in_str *input0, const char *end_trigger); /* setup: */ static int parse_stream_outer(struct in_str *inp, int flag); static int parse_string_outer(const char *s, int flag); @@ -1977,8 +1988,9 @@ static int run_list_real(struct pipe *pi) { rcode = checkjobs(pi); } - debug_printf("checkjobs returned %d\n", rcode); + debug_printf_exec("checkjobs returned %d\n", rcode); } + debug_printf_exec("setting last_return_code=%d\n", rcode); last_return_code = rcode; pi->num_progs = save_num_progs; /* restore number of programs */ if (rmode == RES_IF || rmode == RES_ELIF) @@ -2519,7 +2531,7 @@ static int reserved_word(o_string *dest, struct p_context *ctx) return 0; } -/* normal return is 0. +/* Normal return is 0. * Syntax or xglob errors return 1. */ static int done_word(o_string *dest, struct p_context *ctx) { @@ -2527,9 +2539,9 @@ static int done_word(o_string *dest, struct p_context *ctx) glob_t *glob_target; int gr, flags = 0; - debug_printf("done_word: %s %p\n", dest->data, child); + debug_printf_parse("done_word: '%s' %p\n", dest->data, child); if (dest->length == 0 && !dest->nonnull) { - debug_printf(" true null, ignored\n"); + debug_printf_parse("done_word return 0: true null, ignored\n"); return 0; } if (ctx->pending_redirect) { @@ -2537,24 +2549,31 @@ static int done_word(o_string *dest, struct p_context *ctx) } else { if (child->group) { syntax(); - return 1; /* syntax error, groups and arglists don't mix */ + debug_printf_parse("done_word return 1: syntax error, groups and arglists don't mix\n"); + return 1; } if (!child->argv && (ctx->type & FLAG_PARSE_SEMICOLON)) { - debug_printf("checking %s for reserved-ness\n", dest->data); - if (reserved_word(dest, ctx)) + debug_printf_parse(": checking %s for reserved-ness\n", dest->data); + if (reserved_word(dest, ctx)) { + debug_printf_parse("done_word return %d\n", (ctx->w == RES_SNTX)); return (ctx->w == RES_SNTX); + } } glob_target = &child->glob_result; if (child->argv) flags |= GLOB_APPEND; } gr = xglob(dest, flags, glob_target); - if (gr != 0) return 1; + if (gr != 0) { + debug_printf_parse("done_word return 1: xglob returned %d\n", gr); + return 1; + } b_reset(dest); if (ctx->pending_redirect) { ctx->pending_redirect = NULL; if (glob_target->gl_pathc != 1) { bb_error_msg("ambiguous redirect"); + debug_printf_parse("done_word return 1: ambiguous redirect\n"); return 1; } } else { @@ -2564,6 +2583,7 @@ static int done_word(o_string *dest, struct p_context *ctx) done_word(dest, ctx); done_pipe(ctx, PIPE_SEQ); } + debug_printf_parse("done_word return 0\n"); return 0; } @@ -2614,7 +2634,7 @@ static int done_pipe(struct p_context *ctx, pipe_style type) { struct pipe *new_p; done_command(ctx); /* implicit closure of previous command */ - debug_printf("done_pipe, type %d\n", type); + debug_printf_parse("done_pipe, type %d\n", type); ctx->pipe->followup = type; ctx->pipe->r_mode = ctx->w; new_p = new_pipe(); @@ -2710,7 +2730,8 @@ static FILE *generate_stream_from_list(struct pipe *head) /* this version hacked for testing purposes */ /* return code is exit status of the process that is run. */ -static int process_command_subs(o_string *dest, struct p_context *ctx, struct in_str *input, int subst_end) +static int process_command_subs(o_string *dest, struct p_context *ctx, + struct in_str *input, const char *subst_end) { int retcode; o_string result = NULL_O_STRING; @@ -2732,7 +2753,7 @@ static int process_command_subs(o_string *dest, struct p_context *ctx, struct in setup_file_in_str(&pipe_str, p); /* now send results of command back into original context */ - retcode = parse_stream(dest, ctx, &pipe_str, '\0'); + retcode = parse_stream(dest, ctx, &pipe_str, NULL); /* XXX In case of a syntax error, should we try to kill the child? * That would be tough to do right, so just read until EOF. */ if (retcode == 1) { @@ -2757,21 +2778,25 @@ static int process_command_subs(o_string *dest, struct p_context *ctx, struct in static int parse_group(o_string *dest, struct p_context *ctx, struct in_str *input, int ch) { - int rcode, endch = 0; + int rcode; + const char *endch = NULL; struct p_context sub; struct child_prog *child = ctx->child; + + debug_printf_parse("parse_group entered\n"); if (child->argv) { syntax(); - return 1; /* syntax error, groups and arglists don't mix */ + debug_printf_parse("parse_group return 1: syntax error, groups and arglists don't mix\n"); + return 1; } initialize_context(&sub); switch (ch) { case '(': - endch = ')'; + endch = ")"; child->subshell = 1; break; case '{': - endch = '}'; + endch = "}"; break; default: syntax(); /* really logic error */ @@ -2780,6 +2805,8 @@ static int parse_group(o_string *dest, struct p_context *ctx, done_word(dest, &sub); /* finish off the final word in the subcontext */ done_pipe(&sub, PIPE_SEQ); /* and the final command there, too */ child->group = sub.list_head; + + debug_printf_parse("parse_group return %d\n", rcode); return rcode; /* child remains "open", available for possible redirects */ } @@ -2880,7 +2907,7 @@ static int handle_dollar(o_string *dest, struct p_context *ctx, struct in_str *i break; case '(': b_getch(input); - process_command_subs(dest, ctx, input, ')'); + process_command_subs(dest, ctx, input, ")"); break; case '*': sep[0] = ifs[0]; @@ -2913,12 +2940,12 @@ static int parse_string(o_string *dest, struct p_context *ctx, const char *src) { struct in_str foo; setup_string_in_str(&foo, src); - return parse_stream(dest, ctx, &foo, '\0'); + return parse_stream(dest, ctx, &foo, NULL); } /* return code is 0 for normal exit, 1 for syntax error */ static int parse_stream(o_string *dest, struct p_context *ctx, - struct in_str *input, int end_trigger) + struct in_str *input, const char *end_trigger) { int ch, m; int redir_fd; @@ -2929,30 +2956,38 @@ static int parse_stream(o_string *dest, struct p_context *ctx, * A single-quote triggers a bypass of the main loop until its mate is * found. When recursing, quote state is passed in via dest->quote. */ - debug_printf("parse_stream, end_trigger=%d\n", end_trigger); + debug_printf_parse("parse_stream entered, end_trigger='%s'\n", end_trigger); + while ((ch = b_getch(input)) != EOF) { m = map[ch]; next = (ch == '\n') ? 0 : b_peek(input); - debug_printf("parse_stream: ch=%c (%d) m=%d quote=%d\n", + debug_printf_parse(": ch=%c (%d) m=%d quote=%d\n", ch, ch, m, dest->quote); - if (m == 0 || ((m == 1 || m == 2) && dest->quote)) { + if (m == MAP_ORDINARY + || (m != MAP_NEVER_FLOWTROUGH && dest->quote) + ) { b_addqchr(dest, ch, dest->quote); continue; } - if (m == 2) { /* unquoted IFS */ + if (m == MAP_IFS_IF_UNQUOTED) { if (done_word(dest, ctx)) { + debug_printf_parse("parse_stream return 1\n"); return 1; } - /* If we aren't performing a substitution, treat a newline as a - * command separator. */ - if (end_trigger != '\0' && ch == '\n') + /* If we aren't performing a substitution, treat + * a newline as a command separator. + * [why we don't handle it exactly like ';'? --vda] */ + if (end_trigger && ch == '\n') { done_pipe(ctx, PIPE_SEQ); + } } - if (ch == end_trigger && !dest->quote && ctx->w == RES_NONE) { - debug_printf("leaving parse_stream (triggered)\n"); + if ((end_trigger && strchr(end_trigger, ch)) + && !dest->quote && ctx->w == RES_NONE + ) { + debug_printf_parse("parse_stream return 0\n"); return 0; } - if (m == 2) + if (m == MAP_IFS_IF_UNQUOTED) continue; switch (ch) { case '#': @@ -2970,13 +3005,17 @@ static int parse_stream(o_string *dest, struct p_context *ctx, case '\\': if (next == EOF) { syntax(); + debug_printf_parse("parse_stream return 1\n"); return 1; } b_addqchr(dest, '\\', dest->quote); b_addqchr(dest, b_getch(input), dest->quote); break; case '$': - if (handle_dollar(dest, ctx, input) != 0) return 1; + if (handle_dollar(dest, ctx, input) != 0) { + debug_printf_parse("parse_stream return 1: handle_dollar returned non-0\n"); + return 1; + } break; case '\'': dest->nonnull = 1; @@ -2988,6 +3027,7 @@ static int parse_stream(o_string *dest, struct p_context *ctx, } if (ch == EOF) { syntax(); + debug_printf_parse("parse_stream return 1\n"); return 1; } break; @@ -2996,7 +3036,7 @@ static int parse_stream(o_string *dest, struct p_context *ctx, dest->quote = !dest->quote; break; case '`': - process_command_subs(dest, ctx, input, '`'); + process_command_subs(dest, ctx, input, "`"); break; case '>': redir_fd = redirect_opt_num(dest); @@ -3007,6 +3047,7 @@ static int parse_stream(o_string *dest, struct p_context *ctx, b_getch(input); } else if (next == '(') { syntax(); /* until we support >(list) Process Substitution */ + debug_printf_parse("parse_stream return 1: >(process) not supported\n"); return 1; } setup_redirect(ctx, redir_fd, redir_style, input); @@ -3023,6 +3064,7 @@ static int parse_stream(o_string *dest, struct p_context *ctx, b_getch(input); } else if (next == '(') { syntax(); /* until we support <(list) Process Substitution */ + debug_printf_parse("parse_stream return 1: <(process) not supported\n"); return 1; } setup_redirect(ctx, redir_fd, redir_style, input); @@ -3054,28 +3096,32 @@ static int parse_stream(o_string *dest, struct p_context *ctx, break; case '(': case '{': - if (parse_group(dest, ctx, input, ch) != 0) + if (parse_group(dest, ctx, input, ch) != 0) { + debug_printf_parse("parse_stream return 1: parse_group returned non-0\n"); return 1; + } break; case ')': case '}': - syntax(); /* Proper use of this character caught by end_trigger */ + syntax(); /* Proper use of this character is caught by end_trigger */ + debug_printf_parse("parse_stream return 1: unexpected '}'\n"); return 1; default: syntax(); /* this is really an internal logic error */ + debug_printf_parse("parse_stream return 1: internal logic error\n"); return 1; } } - /* complain if quote? No, maybe we just finished a command substitution + /* Complain if quote? No, maybe we just finished a command substitution * that was quoted. Example: * $ echo "`cat foo` plus more" * and we just got the EOF generated by the subshell that ran "cat foo" - * The only real complaint is if we got an EOF when end_trigger != '\0', + * The only real complaint is if we got an EOF when end_trigger != NULL, * that is, we were really supposed to get end_trigger, and never got * one before the EOF. Can't use the standard "syntax error" return code, * so that parse_stream_outer can distinguish the EOF and exit smoothly. */ - debug_printf("leaving parse_stream (EOF)\n"); - if (end_trigger != '\0') + debug_printf_parse("parse_stream return -%d\n", end_trigger != NULL); + if (end_trigger) return -1; return 0; } @@ -3097,17 +3143,17 @@ static void update_ifs_map(void) * The map[] array only really needs two bits each, and on most machines * that would be faster because of the reduced L1 cache footprint. */ - memset(map, 0, sizeof(map)); /* most characters flow through always */ - mapset("\\$'\"`", 3); /* never flow through */ - mapset("<>;&|(){}#", 1); /* flow through if quoted */ - mapset(ifs, 2); /* also flow through if quoted */ + memset(map, MAP_ORDINARY, sizeof(map)); /* most chars flow through always */ + mapset("\\$'\"`", MAP_NEVER_FLOWTROUGH); + mapset("<>;&|(){}#", MAP_FLOWTROUGH_IF_QUOTED); + mapset(ifs, MAP_IFS_IF_UNQUOTED); /* also flow through if quoted */ } /* most recursion does not come through here, the exception is * from builtin_source() */ static int parse_stream_outer(struct in_str *inp, int flag) { -// FIXME: 'true | exit 3; echo $?' is parsed as a whole, +// FIXME: '{ true | exit 3; echo $? }' is parsed as a whole, // as a result $? is replaced by 0, not 3! // Need to stop & execute stuff at ';', not parse till EOL! @@ -3119,11 +3165,11 @@ static int parse_stream_outer(struct in_str *inp, int flag) initialize_context(&ctx); update_ifs_map(); if (!(flag & FLAG_PARSE_SEMICOLON) || (flag & FLAG_REPARSING)) - mapset(";$&|", 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(); } |