bc: parse file arguments piecemeal (do not read entire file)

function                                             old     new   delta
bc_read_line                                         336     406     +70
zbc_vm_execute_FILE                                    -      67     +67
zbc_lex_next                                        2309    2318      +9
zbc_program_exec                                    4002    4008      +6
bc_program_index                                      66      64      -2
bc_vm_run                                            139     124     -15
zbc_vm_file                                          208      32    -176
------------------------------------------------------------------------------
(add/remove: 1/0 grow/shrink: 3/3 up/down: 152/-193)          Total: -41 bytes
   text	   data	    bss	    dec	    hex	filename
 981736	    485	   7296	 989517	  f194d	busybox_old
 981667	    485	   7296	 989448	  f1908	busybox_unstripped

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 78 insertions, 105 deletions

diff --git a/miscutils/bc.c b/miscutils/bc.c
index c92f6f813..2570e8313 100644
--- a/miscutils/bc.c
+++ b/miscutils/bc.c
@@ -694,7 +694,6 @@ struct globals {
         IF_FEATURE_BC_SIGNALS(smallint ttyin;)
         IF_FEATURE_CLEAN_UP(smallint exiting;)
         smallint in_read;
-        smallint use_stdin;
 
         BcParse prs;
         BcProgram prog;
@@ -704,7 +703,8 @@ struct globals {
         unsigned err_line;
 
         BcVec files;
-        BcVec stdin_buffer;
+        BcVec input_buffer;
+        FILE *input_fp;
 
         char *env_args;
 
@@ -1317,8 +1317,8 @@ static int bad_input_byte(char c)
         return 0;
 }
 
-// Note: it _appends_ data from the stdin to vec.
-static void bc_read_line(BcVec *vec)
+// Note: it _appends_ data from fp to vec.
+static void bc_read_line(BcVec *vec, FILE *fp)
 {
  again:
         fflush_and_check();
@@ -1326,6 +1326,17 @@ static void bc_read_line(BcVec *vec)
 #if ENABLE_FEATURE_BC_SIGNALS
         if (G_interrupt) { // ^C was pressed
  intr:
+                if (fp != stdin) {
+                        // ^C while running a script (bc SCRIPT): die.
+                        // We do not return to interactive prompt:
+                        // user might be running us from a shell,
+                        // and SCRIPT might be intended to terminate
+                        // (e.g. contain a "halt" stmt).
+                        // ^C dropping user into a bc prompt instead of
+                        // the shell would be unexpected.
+                        xfunc_die();
+                }
+                // ^C while interactive input
                 G_interrupt = 0;
                 // GNU bc says "interrupted execution."
                 // GNU dc says "Interrupt!"
@@ -1333,14 +1344,14 @@ static void bc_read_line(BcVec *vec)
         }
 
 # if ENABLE_FEATURE_EDITING
-        if (G_ttyin) {
+        if (G_ttyin && fp == stdin) {
                 int n, i;
 #  define line_buf bb_common_bufsiz1
                 n = read_line_input(G.line_input_state, "", line_buf, COMMON_BUFSIZE);
                 if (n <= 0) { // read errors or EOF, or ^D, or ^C
                         if (n == 0) // ^C
                                 goto intr;
-                        bc_vec_pushZeroByte(vec);
+                        bc_vec_pushZeroByte(vec); // ^D or EOF (or error)
                         return;
                 }
                 i = 0;
@@ -1359,60 +1370,38 @@ static void bc_read_line(BcVec *vec)
                 bool bad_chars = 0;
                 size_t len = vec->len;
 
-                IF_FEATURE_BC_SIGNALS(errno = 0;)
                 do {
-                        c = fgetc(stdin);
-#if ENABLE_FEATURE_BC_SIGNALS && !ENABLE_FEATURE_EDITING
-                        // Both conditions appear simultaneously, check both just in case
-                        if (errno == EINTR || G_interrupt) {
-                                // ^C was pressed
-                                clearerr(stdin);
+#if ENABLE_FEATURE_BC_SIGNALS
+                        if (G_interrupt) {
+                                // ^C was pressed: ignore entire line, get another one
+                                vec->len = len;
                                 goto intr;
                         }
 #endif
+                        c = fgetc(fp);
                         if (c == EOF) {
-                                if (ferror(stdin))
-                                        quit(); // this emits error message
-                                // Note: EOF does not append '\n', therefore:
-                                // printf 'print 123\n' | bc - works
-                                // printf 'print 123' | bc   - fails (syntax error)
+                                if (ferror(fp))
+                                        bb_perror_msg_and_die("input error");
+                                // Note: EOF does not append '\n'
                                 break;
                         }
                         bad_chars |= bad_input_byte(c);
                         bc_vec_pushByte(vec, (char)c);
                 } while (c != '\n');
+
                 if (bad_chars) {
-                        // Bad chars on this line, ignore entire line
-                        vec->len = len;
-                        goto again;
+                        // Bad chars on this line
+                        if (!G.prog.file) { // stdin
+                                // ignore entire line, get another one
+                                vec->len = len;
+                                goto again;
+                        }
+                        bb_perror_msg_and_die("file '%s' is not text", G.prog.file);
                 }
                 bc_vec_pushZeroByte(vec);
         }
 }
 
-static char* bc_read_file(const char *path)
-{
-        char *buf;
-        size_t size = ((size_t) -1);
-        size_t i;
-
-        // Never returns NULL (dies on errors)
-        buf = xmalloc_xopen_read_close(path, &size);
-
-        for (i = 0; i < size; ++i) {
-                char c = buf[i];
-                if ((c < ' ' && c != '\t' && c != '\r' && c != '\n') // also allow '\v' '\f'?
-                 || c > 0x7e
-                ) {
-                        free(buf);
-                        buf = NULL;
-                        break;
-                }
-        }
-
-        return buf;
-}
-
 static void bc_num_setToZero(BcNum *n, size_t scale)
 {
         n->len = 0;
@@ -2912,7 +2901,7 @@ static bool bc_lex_more_input(BcLex *l)
         size_t str;
         bool comment;
 
-        bc_vec_pop_all(&G.stdin_buffer);
+        bc_vec_pop_all(&G.input_buffer);
 
         // This loop is complex because the vm tries not to send any lines that end
         // with a backslash to the parser. The reason for that is because the parser
@@ -2921,18 +2910,18 @@ static bool bc_lex_more_input(BcLex *l)
         comment = false;
         str = 0;
         for (;;) {
-                size_t prevlen = G.stdin_buffer.len;
+                size_t prevlen = G.input_buffer.len;
                 char *string;
 
-                bc_read_line(&G.stdin_buffer);
+                bc_read_line(&G.input_buffer, G.input_fp);
                 // No more input means EOF
-                if (G.stdin_buffer.len <= prevlen + 1) // (we expect +1 for NUL byte)
+                if (G.input_buffer.len <= prevlen + 1) // (we expect +1 for NUL byte)
                         break;
 
-                string = G.stdin_buffer.v + prevlen;
+                string = G.input_buffer.v + prevlen;
                 while (*string) {
                         char c = *string;
-                        if (string == G.stdin_buffer.v || string[-1] != '\\') {
+                        if (string == G.input_buffer.v || string[-1] != '\\') {
                                 if (IS_BC)
                                         str ^= (c == '"');
                                 else {
@@ -2954,7 +2943,7 @@ static bool bc_lex_more_input(BcLex *l)
                         }
                 }
                 if (str != 0 || comment) {
-                        G.stdin_buffer.len--; // backstep over the trailing NUL byte
+                        G.input_buffer.len--; // backstep over the trailing NUL byte
                         continue;
                 }
 
@@ -2963,21 +2952,20 @@ static bool bc_lex_more_input(BcLex *l)
                 // if it is not, then it's EOF, and looping back
                 // to bc_read_line() will detect it:
                 string -= 2;
-                if (string >= G.stdin_buffer.v && *string == '\\') {
-                        G.stdin_buffer.len--;
+                if (string >= G.input_buffer.v && *string == '\\') {
+                        G.input_buffer.len--;
                         continue;
                 }
 
                 break;
         }
 
-        l->buf = G.stdin_buffer.v;
+        l->buf = G.input_buffer.v;
         l->i = 0;
-//bb_error_msg("G.stdin_buffer.len:%d '%s'", G.stdin_buffer.len, G.stdin_buffer.v);
-        l->len = G.stdin_buffer.len - 1; // do not include NUL
+//      bb_error_msg("G.input_buffer.len:%d '%s'", G.input_buffer.len, G.input_buffer.v);
+        l->len = G.input_buffer.len - 1; // do not include NUL
 
-        G.use_stdin = (l->len != 0);
-        return G.use_stdin;
+        return l->len != 0;
 }
 
 static BC_STATUS zbc_lex_next(BcLex *l)
@@ -2989,22 +2977,23 @@ static BC_STATUS zbc_lex_next(BcLex *l)
 
         l->line += l->newline;
         G.err_line = l->line;
-
-        l->t.t = BC_LEX_EOF;
-//this NL handling is bogus
-        l->newline = (l->i == l->len);
-        if (l->newline) {
-                if (!G.use_stdin || !bc_lex_more_input(l))
-                        RETURN_STATUS(BC_STATUS_SUCCESS);
-                // here it's guaranteed that l->i is below l->len
-                l->newline = false;
-        }
+        l->newline = false;
 
         // Loop until failure or we don't have whitespace. This
         // is so the parser doesn't get inundated with whitespace.
         // Comments are also BC_LEX_WHITESPACE tokens and eaten here.
         s = BC_STATUS_SUCCESS;
         do {
+                l->t.t = BC_LEX_EOF;
+                if (l->i == l->len) {
+                        if (!G.input_fp)
+                                RETURN_STATUS(BC_STATUS_SUCCESS);
+                        if (!bc_lex_more_input(l)) {
+                                G.input_fp = NULL;
+                                RETURN_STATUS(BC_STATUS_SUCCESS);
+                        }
+                        // here it's guaranteed that l->i is below l->len
+                }
                 dbg_lex("next string to parse:'%.*s'",
                         (int)(strchrnul(l->buf + l->i, '\n') - (l->buf + l->i)),
                         l->buf + l->i);
@@ -5351,7 +5340,7 @@ static BC_STATUS zbc_program_read(void)
         G.in_read = 1;
 
         bc_char_vec_init(&buf);
-        bc_read_line(&buf);
+        bc_read_line(&buf, stdin);
 
         bc_parse_create(&parse, BC_PROG_READ);
         bc_lex_file(&parse.l);
@@ -6931,60 +6920,44 @@ static BC_STATUS zbc_vm_process(const char *text)
 # define zbc_vm_process(...) (zbc_vm_process(__VA_ARGS__), BC_STATUS_SUCCESS)
 #endif
 
-static BC_STATUS zbc_vm_file(const char *file)
+static BC_STATUS zbc_vm_execute_FILE(FILE *fp, const char *filename)
 {
         // So far bc/dc have no way to include a file from another file,
         // therefore we know G.prog.file == NULL on entry
         //const char *sv_file;
-        char *data;
         BcStatus s;
-        BcFunc *main_func;
-        BcInstPtr *ip;
-
-        data = bc_read_file(file);
-        if (!data) RETURN_STATUS(bc_error_fmt("file '%s' is not text", file));
 
-        //sv_file = G.prog.file;
-        G.prog.file = file;
+        G.prog.file = filename;
+        G.input_fp = fp;
         bc_lex_file(&G.prs.l);
-        s = zbc_vm_process(data);
-        if (s) goto err;
-
-        main_func = bc_program_func(BC_PROG_MAIN);
-        ip = bc_vec_item(&G.prog.stack, 0);
-
-        if (main_func->code.len < ip->idx)
-                s = bc_error_fmt("file '%s' is not executable", file);
 
-err:
-        //G.prog.file = sv_file;
+        do {
+                s = zbc_vm_process("");
+                // We do not stop looping on errors here if reading stdin.
+                // Example: start interactive bc and enter "return".
+                // It should say "'return' not in a function"
+                // but should not exit.
+        } while (G.input_fp == stdin);
         G.prog.file = NULL;
-        free(data);
         RETURN_STATUS(s);
 }
 #if ERRORS_ARE_FATAL
-# define zbc_vm_file(...) (zbc_vm_file(__VA_ARGS__), BC_STATUS_SUCCESS)
+# define zbc_vm_execute_FILE(...) (zbc_vm_execute_FILE(__VA_ARGS__), BC_STATUS_SUCCESS)
 #endif
 
-static BC_STATUS zbc_vm_stdin(void)
+static BC_STATUS zbc_vm_file(const char *file)
 {
         BcStatus s;
+        FILE *fp;
 
-        //G.prog.file = NULL; - already is
-        bc_lex_file(&G.prs.l);
+        fp = xfopen_for_read(file);
+        s = zbc_vm_execute_FILE(fp, file);
+        fclose(fp);
 
-        G.use_stdin = 1;
-        do {
-                s = zbc_vm_process("");
-                // We do not stop looping on errors here.
-                // Example: start interactive bc and enter "return".
-                // It should say "'return' not in a function"
-                // but should not exit.
-        } while (G.use_stdin);
         RETURN_STATUS(s);
 }
 #if ERRORS_ARE_FATAL
-# define zbc_vm_stdin(...) (zbc_vm_stdin(__VA_ARGS__), BC_STATUS_SUCCESS)
+# define zbc_vm_file(...) (zbc_vm_file(__VA_ARGS__), BC_STATUS_SUCCESS)
 #endif
 
 #if ENABLE_BC
@@ -7257,7 +7230,7 @@ static BC_STATUS zbc_vm_exec(void)
         }
 
         if (IS_BC || (option_mask32 & BC_FLAG_I))
-                s = zbc_vm_stdin();
+                s = zbc_vm_execute_FILE(stdin, /*filename:*/ NULL);
 
         RETURN_STATUS(s);
 }
@@ -7287,7 +7260,7 @@ static void bc_program_free(void)
         bc_num_free(&G.prog.last);
         bc_num_free(&G.prog.zero);
         bc_num_free(&G.prog.one);
-        bc_vec_free(&G.stdin_buffer);
+        bc_vec_free(&G.input_buffer);
 }
 
 static void bc_vm_free(void)
@@ -7352,7 +7325,7 @@ static void bc_program_init(void)
         bc_vec_init(&G.prog.stack, sizeof(BcInstPtr), NULL);
         bc_vec_push(&G.prog.stack, &ip);
 
-        bc_char_vec_init(&G.stdin_buffer);
+        bc_char_vec_init(&G.input_buffer);
 }
 
 static int bc_vm_init(const char *env_len)