← Commit list

d17a91db6

Denys Vlasenko

2016-09-29

SUCCESS Duration: 267s

Subject

hush: rework input char buffering to allow more than one-deep peek

Binary

No binary (build failed)

Architecture & Compiler Flags

Architecture: x86_64-linux-gnu Compiler: gcc (Ubuntu 11.4.0-1ubuntu1~22.04.3) 11.4.0

—

Build Log

(log yok)

Commit Diff GitHub →

shell/hush.c +125 -68

shell/hush.c+125 -68

@@ -462,19 +462,19 @@ static const char *const assignment_flag[] = {

	typedef struct in_str {
	const char *p;
-	/* eof_flag=1: last char in ->p is really an EOF */
-	char eof_flag; /* meaningless if ->p == NULL */
-	char peek_buf[2];
	#if ENABLE_HUSH_INTERACTIVE
	smallint promptmode; /* 0: PS1, 1: PS2 */
	#endif
+	int peek_buf[2];
	int last_char;
	FILE *file;
	int (get) (struct in_str ) FAST_FUNC;
	int (peek) (struct in_str ) FAST_FUNC;
+	int (peek2) (struct in_str ) FAST_FUNC;
	} in_str;
	#define i_getch(input) ((input)->get(input))
-	#define i_peek(input) ((input)->peek(input))
+	#define i_peek(input) ((input)->peek(input))
+	#define i_peek2(input) ((input)->peek2(input))

	/* The descrip member of this structure is only used to make
	* debugging output pretty */
@@ -2122,28 +2122,11 @@ static void reinit_unicode_for_hush(void)
	}
	}

-
	/*
-	* in_str support
+	* in_str support (strings, and "strings" read from files).
	*/
-	static int FAST_FUNC static_get(struct in_str *i)
-	{
-	int ch = *i->p;
-	if (ch != '\0') {
-	i->p++;
-	i->last_char = ch;
-	return ch;
-	}
-	return EOF;
-	}
-
-	static int FAST_FUNC static_peek(struct in_str *i)
-	{
-	return *i->p;
-	}

	#if ENABLE_HUSH_INTERACTIVE
-
	static void cmdedit_update_prompt(void)
	{
	if (ENABLE_FEATURE_EDITING_FANCY_PROMPT) {
@@ -2157,7 +2140,6 @@ static void cmdedit_update_prompt(void)
	if (G.PS2 == NULL)
	G.PS2 = "> ";
	}
-
	static const char *setup_prompt_string(int promptmode)
	{
	const char *prompt_str;
@@ -2178,8 +2160,7 @@ static const char *setup_prompt_string(int promptmode)
	debug_printf("result '%s'\n", prompt_str);
	return prompt_str;
	}
-
-	static void get_user_input(struct in_str *i)
+	static int get_user_input(struct in_str *i)
	{
	int r;
	const char *prompt_str;
@@ -2197,11 +2178,14 @@ static void get_user_input(struct in_str *i)
	/* catch SIGINT etc (^C is handled by read_line_input) */
	check_and_run_traps();
	} while (r == 0 \|\| G.flag_SIGINT); /* repeat if ^C or SIGINT */
-	i->eof_flag = (r < 0);
-	if (i->eof_flag) { /* EOF/error detected */
-	G.user_input_buf[0] = EOF; /* yes, it will be truncated, it's ok */
-	G.user_input_buf[1] = '\0';
+	i->p = G.user_input_buf;
+	if (r < 0) {
+	/* EOF/error detected */
+	G.user_input_buf[0] = '\0';
+	i->peek_buf[1] = i->peek_buf[0] = r = EOF;
+	return r;
	}
+	return (unsigned char)*i->p++;
	# else
	do {
	G.flag_SIGINT = 0;
@@ -2215,14 +2199,11 @@ static void get_user_input(struct in_str *i)
	fputs(prompt_str, stdout);
	}
	fflush_all();
-	G.user_input_buf[0] = r = fgetc(i->file);
-	/G.user_input_buf[1] = '\0'; - already is and never changed /
-	} while (G.flag_SIGINT);
-	i->eof_flag = (r == EOF);
+	r = fgetc(i->file);
+	} while (G.flag_SIGINT \|\| r == '\0');
+	return r;
	# endif
-	i->p = G.user_input_buf;
	}
-
	#endif /* INTERACTIVE */

	/* This is the magic location that prints prompts
@@ -2232,28 +2213,36 @@ static int FAST_FUNC file_get(struct in_str *i)
	int ch;

	/* If there is data waiting, eat it up */
-	if (i->p && *i->p) {
-	#if ENABLE_HUSH_INTERACTIVE
-	take_cached:
-	#endif
-	ch = *i->p++;
-	if (i->eof_flag && !*i->p)
-	ch = EOF;
-	/* note: ch is never NUL */
-	} else {
-	/* need to double check i->file because we might be doing something
-	* more complicated by now, like sourcing or substituting. */
+	/* peek_buf[] is an int array, not char. Can contain EOF. */
+	ch = i->peek_buf[0];
+	if (ch != '\0') {
+	int ch2 = i->peek_buf[1];
+	i->peek_buf[0] = ch2;
+	if (ch2 == 0) /* very likely, avoid redundant write */
+	goto out;
+	i->peek_buf[1] = 0;
+	goto out;
+	}
+
	#if ENABLE_HUSH_INTERACTIVE
-	if (G_interactive_fd && i->file == stdin) {
-	do {
-	get_user_input(i);
-	} while (!i->p); / need non-empty line */
-	i->promptmode = 1; /* PS2 */
-	goto take_cached;
-	}
-	#endif
-	do ch = fgetc(i->file); while (ch == '\0');
+	/* This can be stdin, check line editing char[] buffer */
+	if (i->p && *i->p != '\0') {
+	ch = (unsigned char)*i->p++;
+	goto out;
+	}
+	/* It's empty.
+	* If it's interactive stdin, get new line.
+	*/
+	if (G_interactive_fd && i->file == stdin) {
+	/* Returns first char (or EOF), the rest are in i->p[] */
+	ch = get_user_input(i);
+	i->promptmode = 1; /* PS2 */
+	goto out;
	}
+	/* Not stdin: script file */
+	#endif
+	do ch = fgetc(i->file); while (ch == '\0');
+	out:
	debug_printf("file_get: got '%c' %d\n", ch, ch);
	i->last_char = ch;
	return ch;
@@ -2265,26 +2254,82 @@ static int FAST_FUNC file_get(struct in_str *i)
	static int FAST_FUNC file_peek(struct in_str *i)
	{
	int ch;
-	if (i->p && *i->p) {
-	if (i->eof_flag && !i->p[1])
-	return EOF;
-	return *i->p;
-	/* note: ch is never NUL */
-	}
+
+	/* peek_buf[] is an int array, not char. Can contain EOF. */
+	ch = i->peek_buf[0];
+	if (ch != '\0')
+	return ch;
+
+	#if ENABLE_HUSH_INTERACTIVE
+	/* This can be stdin, check line editing char[] buffer */
+	if (i->p && *i->p != '\0')
+	return (unsigned char)*i->p;
+	#endif
+
	do ch = fgetc(i->file); while (ch == '\0');
-	i->eof_flag = (ch == EOF);
	i->peek_buf[0] = ch;
-	i->peek_buf[1] = '\0';
-	i->p = i->peek_buf;
+	i->peek_buf[1] = 0;
	debug_printf("file_peek: got '%c' %d\n", ch, ch);
	return ch;
	}

+	/* Only ever called if i_peek() was called, and did not return EOF */
+	static int FAST_FUNC file_peek2(struct in_str *i)
+	{
+	int ch;
+
+	/* peek_buf[] is an int array, not char. Can contain EOF. */
+	ch = i->peek_buf[0];
+	if (ch != 0) {
+	/* peek_buf[] is not empty. Is there 2nd char? */
+	ch = i->peek_buf[1];
+	if (ch == 0) {
+	/* We did not read it yet, get it now */
+	do ch = fgetc(i->file); while (ch == '\0');
+	i->peek_buf[1] = ch;
+	}
+	goto out;
+	}
+
+	#if ENABLE_HUSH_INTERACTIVE
+	/* This can be stdin, check line editing char[] buffer */
+	if (i->p && i->p[0] != '\0')
+	ch = i->p[1];
+	#endif
+	out:
+	debug_printf("file_peek2: got '%c' %d\n", ch, ch);
+	return ch;
+	}
+
+	static int FAST_FUNC static_get(struct in_str *i)
+	{
+	int ch = *i->p;
+	if (ch != '\0') {
+	i->p++;
+	i->last_char = ch;
+	return ch;
+	}
+	return EOF;
+	}
+
+	static int FAST_FUNC static_peek(struct in_str *i)
+	{
+	/* Doesn't report EOF on NUL. None of the callers care. */
+	return *i->p;
+	}
+
+	/* Only ever called if i_peek() was called, and did not return EOF */
+	static int FAST_FUNC static_peek2(struct in_str *i)
+	{
+	return i->p[1];
+	}
+
	static void setup_file_in_str(struct in_str i, FILE f)
	{
	memset(i, 0, sizeof(*i));
-	i->peek = file_peek;
	i->get = file_get;
+	i->peek = file_peek;
+	i->peek2 = file_peek2;
	/* i->promptmode = 0; - PS1 (memset did it) */
	i->file = f;
	/* i->p = NULL; */
@@ -2293,11 +2338,11 @@ static void setup_file_in_str(struct in_str i, FILE f)
	static void setup_string_in_str(struct in_str i, const char s)
	{
	memset(i, 0, sizeof(*i));
-	i->peek = static_peek;
	i->get = static_get;
+	i->peek = static_peek;
+	i->peek2 = static_peek2;
	/* i->promptmode = 0; - PS1 (memset did it) */
	i->p = s;
-	/* i->eof_flag = 0; */
	}


@@ -4040,9 +4085,21 @@ static int parse_dollar(o_string *as_string,
	debug_printf_parse(": '%c'\n", ch);
	o_addchr(dest, ch \| quote_mask);
	quote_mask = 0;
+	next_ch:
	ch = i_peek(input);
-	if (!isalnum(ch) && ch != '_')
+	if (!isalnum(ch) && ch != '_') {
+	if (ch == '\\') {
+	/* If backslash+newline, skip it */
+	int ch2 = i_peek2(input);
+	if (ch2 == '\n') {
+	i_getch(input);
+	i_getch(input);
+	goto next_ch;
+	}
+	}
+	/* End of variable name reached */
	break;
+	}
	ch = i_getch(input);
	nommu_addchr(as_string, ch);
	}