more: do not allocate shell command buffer from stack

This change has three possitive effects:  Avoid expansion code when it is
not needed.  Stop wasting memory from stack for something rarely needed.
When command buffer is needed stop limiting it's size artificially.

Signed-off-by: Sami Kerola <kerolasa@iki.fi>

diff --git a/text-utils/more.c b/text-utils/more.c
index 98303b4f123c55b1db169975292227eace26f83a..f061e12fd277a74c98263768e17dff577bad4e5e 100644 (file)
--- a/text-utils/more.c
+++ b/text-utils/more.c
@@ -99,7 +99,6 @@
 #define NUM_COLUMNS    80
 #define TERMINAL_BUF   4096
 #define INIT_BUF       80
-#define SHELL_LINE     1000
 #define COMMAND_BUF    200
 #define REGERR_BUF     NUM_COLUMNS
 
@@ -138,7 +137,6 @@ struct more_control {
        char **file_names;              /* The list of file names */
        int num_files;                  /* Number of files left to process */
        char *shell;                    /* name of the shell to use */
-       int previous_shell;             /* does previous shell command exist */
        int sigfd;                      /* signalfd() file descriptor */
        sigset_t sigset;                /* signal operations */
        char *line_buf;                 /* line buffer */
@@ -166,7 +164,7 @@ struct more_control {
        int last_key_command;           /* previous more key command */
        int last_key_arg;               /* previous key command argument */
        int last_colon_command;         /* is a colon-prefixed key command */
-       char shell_line[SHELL_LINE];
+       char *shell_line;               /* line to execute in subshell */
        unsigned int
                bad_stdout:1,           /* true if overwriting does not turn off standout */
                catch_suspend:1,        /* we should catch the SIGTSTP signal */
@@ -748,6 +746,7 @@ static void __attribute__((__noreturn__)) more_exit(struct more_control *ctl)
        } else
                fputc('\n', stderr);
        free(ctl->previous_search);
+       free(ctl->shell_line);
        free(ctl->line_buf);
        _exit(EXIT_SUCCESS);
 }
@@ -979,24 +978,24 @@ static void ttyin(struct more_control *ctl, char buf[], int nmax, char pchar)
                more_error(ctl, _("Line too long"));
 }
 
-static int expand(struct more_control *ctl, char **outbuf, char *inbuf)
+/* Expand shell command line. */
+static void expand(struct more_control *ctl, char *inbuf)
 {
        char *inpstr;
        char *outstr;
        char c;
        char *temp;
-       int changed = 0;
        int tempsz, xtra, offset;
 
        xtra = strlen(ctl->file_names[ctl->argv_position]) + strlen(ctl->shell_line) + 1;
-       tempsz = 200 + xtra;
+       tempsz = COMMAND_BUF + xtra;
        temp = xmalloc(tempsz);
        inpstr = inbuf;
        outstr = temp;
        while ((c = *inpstr++) != '\0') {
                offset = outstr - temp;
                if (tempsz - offset - 1 < xtra) {
-                       tempsz += 200 + xtra;
+                       tempsz += COMMAND_BUF + xtra;
                        temp = xrealloc(temp, tempsz);
                        outstr = temp + offset;
                }
@@ -1005,17 +1004,16 @@ static int expand(struct more_control *ctl, char **outbuf, char *inbuf)
                        if (!ctl->no_tty_in) {
                                strcpy(outstr, ctl->file_names[ctl->argv_position]);
                                outstr += strlen(ctl->file_names[ctl->argv_position]);
-                               changed++;
                        } else
                                *outstr++ = c;
                        break;
                case '!':
-                       if (!ctl->previous_shell)
+                       if (ctl->shell_line) {
+                               strcpy(outstr, ctl->shell_line);
+                               outstr += strlen(ctl->shell_line);
+                       } else
                                more_error(ctl, _
                                           ("No previous command to substitute for"));
-                       strcpy(outstr, ctl->shell_line);
-                       outstr += strlen(ctl->shell_line);
-                       changed++;
                        break;
                case '\\':
                        if (*inpstr == '%' || *inpstr == '!') {
@@ -1028,8 +1026,8 @@ static int expand(struct more_control *ctl, char **outbuf, char *inbuf)
                }
        }
        *outstr++ = '\0';
-       *outbuf = temp;
-       return changed;
+       free(ctl->shell_line);
+       ctl->shell_line = temp;
 }
 
 static void set_tty(struct more_control *ctl)
@@ -1138,39 +1136,27 @@ static void execute(struct more_control *ctl, char *filename, char *cmd, ...)
 static void run_shell(struct more_control *ctl, char *filename)
 {
        char cmdbuf[COMMAND_BUF];
-       int rc;
-       char *expanded;
 
        kill_line(ctl);
        putchar('!');
        fflush(stdout);
        ctl->prompt_len = 1;
-       if (ctl->run_previous_command)
+       if (ctl->run_previous_command && ctl->shell_line)
                fputs(ctl->shell_line, stdout);
        else {
                ttyin(ctl, cmdbuf, sizeof(cmdbuf) - 2, '!');
-               expanded = NULL;
-               rc = expand(ctl, &expanded, cmdbuf);
-               if (expanded) {
-                       if (strlen(expanded) < sizeof(ctl->shell_line))
-                               strcpy(ctl->shell_line, expanded);
-                       else
-                               rc = -1;
-                       free(expanded);
-               }
-               if (rc < 0) {
-                       fputs(_("  Overflow\n"), stderr);
-                       output_prompt(ctl, filename);
-                       return;
-               } else if (rc > 0) {
-                       kill_line(ctl);
-                       ctl->prompt_len = printf("!%s", ctl->shell_line);
+               if (strpbrk(cmdbuf, "%!\\"))
+                       expand(ctl, cmdbuf);
+               else {
+                       free(ctl->shell_line);
+                       ctl->shell_line = xstrdup(cmdbuf);
                }
+               kill_line(ctl);
+               ctl->prompt_len = printf("!%s", ctl->shell_line);
        }
        fflush(stdout);
        fputc('\n', stderr);
        ctl->prompt_len = 0;
-       ctl->previous_shell = 1;
        execute(ctl, filename, ctl->shell, ctl->shell, "-c", ctl->shell_line, 0);
 }