diff options
| -rw-r--r-- | shell/brace.txt | 50 | ||||
| -rw-r--r-- | shell/hush.c | 36 | ||||
| -rw-r--r-- | shell/hush_test/hush-psubst/tick5.right | 1 | ||||
| -rwxr-xr-x | shell/hush_test/hush-psubst/tick5.tests | 1 |
4 files changed, 70 insertions, 18 deletions
diff --git a/shell/brace.txt b/shell/brace.txt new file mode 100644 index 0000000..664861b --- /dev/null +++ b/shell/brace.txt @@ -0,0 +1,50 @@ +Brace Expansion + +Brace expansion is a mechanism by which arbitrary strings may be gener- +ated. This mechanism is similar to pathname expansion, but the file- +names generated need not exist. Patterns to be brace expanded take the +form of an optional preamble, followed by either a series of comma-sep- +arated strings or a sequence expression between a pair of braces, fol- +lowed by an optional postscript. The preamble is prefixed to each +string contained within the braces, and the postscript is then appended +to each resulting string, expanding left to right. + +Brace expansions may be nested. The results of each expanded string +are not sorted; left to right order is preserved. For example, +a{d,c,b}e expands into `ade ace abe'. + +A sequence expression takes the form {x..y}, where x and y are either +integers or single characters. When integers are supplied, the expres- +sion expands to each number between x and y, inclusive. When charac- +ters are supplied, the expression expands to each character lexico- +graphically between x and y, inclusive. Note that both x and y must be +of the same type. + +Brace expansion is performed before any other expansions, and any char- +acters special to other expansions are preserved in the result. It is +strictly textual. Bash does not apply any syntactic interpretation to +the context of the expansion or the text between the braces. + +A correctly-formed brace expansion must contain unquoted opening and +closing braces, and at least one unquoted comma or a valid sequence +expression. Any incorrectly formed brace expansion is left unchanged. +A { or , may be quoted with a backslash to prevent its being considered +part of a brace expression. To avoid conflicts with parameter expan- +sion, the string ${ is not considered eligible for brace expansion. + +This construct is typically used as shorthand when the common prefix of +the strings to be generated is longer than in the above example: + + mkdir /usr/local/src/bash/{old,new,dist,bugs} +or + chown root /usr/{ucb/{ex,edit},lib/{ex?.?*,how_ex}} + +Brace expansion introduces a slight incompatibility with historical +versions of sh. sh does not treat opening or closing braces specially +when they appear as part of a word, and preserves them in the output. +Bash removes braces from words as a consequence of brace expansion. +For example, a word entered to sh as file{1,2} appears identically in +the output. The same word is output as file1 file2 after expansion by +bash. If strict compatibility with sh is desired, start bash with the ++B option or disable brace expansion with the +B option to the set com- +mand diff --git a/shell/hush.c b/shell/hush.c index 891d87b..6f394d1 100644 --- a/shell/hush.c +++ b/shell/hush.c @@ -2287,7 +2287,7 @@ static NOINLINE int expand_vars_to_list(o_string *output, int n, char *arg, char * expanded result may need to be globbed * and $IFS-splitted */ debug_printf_subst("SUBST '%s' first_ch %x\n", arg, first_ch); - process_command_subs(&subst_result, arg); + G.last_exitcode = process_command_subs(&subst_result, arg); debug_printf_subst("SUBST RES '%s'\n", subst_result.data); val = subst_result.data; goto store_val; @@ -3904,7 +3904,7 @@ static NOINLINE int run_pipe(struct pipe *pi) /* if someone gives us an empty string: `cmd with empty output` */ if (!argv_expanded[0]) { debug_leave(); - return 0; + return 0; // or G.last_exitcode? see emptytick.tests } x = find_builtin(argv_expanded[0]); @@ -5202,10 +5202,10 @@ static int fetch_heredocs(int heredoc_cnt, struct parse_context *ctx, struct in_ #if ENABLE_HUSH_TICK -static FILE *generate_stream_from_string(const char *s) +static FILE *generate_stream_from_string(const char *s, pid_t *pid_p) { - FILE *pf; - int pid, channel[2]; + pid_t pid; + int channel[2]; # if !BB_MMU char **to_free; # endif @@ -5291,6 +5291,7 @@ static FILE *generate_stream_from_string(const char *s) } /* parent */ + *pid_p = pid; # if ENABLE_HUSH_FAST G.count_SIGCHLD++; //bb_error_msg("[%d] fork in generate_stream_from_string: G.count_SIGCHLD:%d G.handled_SIGCHLD:%d", getpid(), G.count_SIGCHLD, G.handled_SIGCHLD); @@ -5300,8 +5301,8 @@ static FILE *generate_stream_from_string(const char *s) free(to_free); # endif close(channel[1]); - pf = fdopen(channel[0], "r"); - return pf; +//TODO: libbb: fdopen_or_die? + return fdopen(channel[0], "r"); } /* Return code is exit status of the process that is run. */ @@ -5309,9 +5310,10 @@ static int process_command_subs(o_string *dest, const char *s) { FILE *pf; struct in_str pipe_str; - int ch, eol_cnt; + pid_t pid; + int status, ch, eol_cnt; - pf = generate_stream_from_string(s); + pf = generate_stream_from_string(s, &pid); if (pf == NULL) return 1; close_on_exec_on(fileno(pf)); @@ -5331,16 +5333,14 @@ static int process_command_subs(o_string *dest, const char *s) o_addQchr(dest, ch); } - debug_printf("done reading from pipe, pclose()ing\n"); - /* Note: we got EOF, and we just close the read end of the pipe. - * We do not wait for the `cmd` child to terminate. bash and ash do. - * Try these: - * echo `echo Hi; exec 1>&-; sleep 2` - bash waits 2 sec - * `false`; echo $? - bash outputs "1" - */ + debug_printf("done reading from `cmd` pipe, closing it\n"); fclose(pf); - debug_printf("closed FILE from child. return 0\n"); - return 0; + /* We need to extract exitcode. Test case + * "true; echo `sleep 1; false` $?" + * should print 1 */ + safe_waitpid(pid, &status, 0); + debug_printf("child exited. returning its exitcode:%d\n", WEXITSTATUS(status)); + return WEXITSTATUS(status); } #endif /* ENABLE_HUSH_TICK */ diff --git a/shell/hush_test/hush-psubst/tick5.right b/shell/hush_test/hush-psubst/tick5.right new file mode 100644 index 0000000..d00491f --- /dev/null +++ b/shell/hush_test/hush-psubst/tick5.right @@ -0,0 +1 @@ +1 diff --git a/shell/hush_test/hush-psubst/tick5.tests b/shell/hush_test/hush-psubst/tick5.tests new file mode 100755 index 0000000..bd160c9 --- /dev/null +++ b/shell/hush_test/hush-psubst/tick5.tests @@ -0,0 +1 @@ +true; echo `false` $? |