Experimental support for embeded newline. (im evil)

Fix segfault when using 'N' with an odd number of lines.

2 files changed, 64 insertions, 10 deletions

diff --git a/editors/Config.in b/editors/Config.in
index 4f2817598..c75267759 100644
--- a/editors/Config.in
+++ b/editors/Config.in
@@ -24,6 +24,15 @@ config CONFIG_SED
         help
           Please submit a patch to add help text for this item.
 
+config CONFIG_FEATURE_SED_EMBEDED_NEWLINE
+        bool " Embeded newline (EXPERIMENTAL)"
+        default n
+        depends on CONFIG_SED
+        help
+          This is a hack to allow matching of '\n' in regular expressions.
+          It works by translating '\n' to "\n" and back.
+          It may introduce unexpected results if you use "\n" in your text.
+
 config CONFIG_VI
         bool "vi"
         default n
diff --git a/editors/sed.c b/editors/sed.c
index 1cbf974b6..292bc8662 100644
--- a/editors/sed.c
+++ b/editors/sed.c
@@ -430,7 +430,7 @@ static char *parse_cmd_str(sed_cmd_t * const sed_cmd, char *cmdstr)
 
 static char *add_cmd(sed_cmd_t *sed_cmd, char *cmdstr)
 {
-        
+
         /* Skip over leading whitespace and semicolons */
         cmdstr += strspn(cmdstr, semicolon_whitespace);
 
@@ -491,7 +491,6 @@ static char *add_cmd(sed_cmd_t *sed_cmd, char *cmdstr)
                         cmdstr++;
                 }
 #endif
-
         }
 
         /* last part (mandatory) will be a command */
@@ -529,6 +528,18 @@ static char *add_cmd(sed_cmd_t *sed_cmd, char *cmdstr)
 
 static void add_cmd_str(char *cmdstr)
 {
+#ifdef CONFIG_FEATURE_SED_EMBEDED_NEWLINE
+        char *cmdstr_ptr = cmdstr;
+
+        /* HACK: convert "\n" to match tranlated '\n' string */
+        while((cmdstr_ptr = strstr(cmdstr_ptr, "\\n")) != NULL) {
+                cmdstr = xrealloc(cmdstr, strlen(cmdstr) + 2);
+                cmdstr_ptr = strstr(cmdstr, "\\n");
+                memmove(cmdstr_ptr + 1, cmdstr_ptr, strlen(cmdstr_ptr) + 1);
+                cmdstr_ptr[0] = '\\';
+                cmdstr_ptr += 3;
+        }
+#endif
         do {
                 sed_cmd_t *sed_cmd;
                 sed_cmd = xcalloc(1, sizeof(sed_cmd_t));
@@ -795,8 +806,35 @@ static void process_file(FILE *file)
                                                  *    flag exists in the first place.
                                                  */
 
+#ifdef CONFIG_FEATURE_SED_EMBEDED_NEWLINE
+                                                /* HACK: escape newlines twice so regex can match them */
+                                                {
+                                                        int offset = 0;
+                                                        while(strchr(line + offset, '\n') != NULL) {
+                                                                char *tmp;
+                                                                line = xrealloc(line, strlen(line) + 2);
+                                                                tmp = strchr(line + offset, '\n');
+                                                                memmove(tmp + 1, tmp, strlen(tmp) + 1);
+                                                                tmp[0] = '\\';
+                                                                tmp[1] = 'n';
+                                                                offset = tmp - line + 2;
+                                                        }
+                                                }
+#endif
                                                 /* we print the line once, unless we were told to be quiet */
                                                 substituted = do_subst_command(sed_cmd, &line);
+
+#ifdef CONFIG_FEATURE_SED_EMBEDED_NEWLINE
+                                                /* undo HACK: escape newlines twice so regex can match them */
+                                                {
+                                                        char *tmp = line;
+
+                                                        while((tmp = strstr(tmp, "\\n")) != NULL) {
+                                                                memmove(tmp, tmp + 1, strlen(tmp + 1) + 1);
+                                                                tmp[0] = '\n';
+                                                        }
+                                                }
+#endif
                                                 altered |= substituted;
                                                 if (!be_quiet && altered && ((sed_cmd->linear == NULL) || (sed_cmd->linear->cmd != 's'))) {
                                                         force_print = 1;
@@ -857,11 +895,13 @@ static void process_file(FILE *file)
                                                 linenum++;
                                                 break;
                                         case 'N':       /* Append the next line to the current line */
-                                                line = realloc(line, strlen(line) + strlen(next_line) + 2);
-                                                strcat(line, "\n");
-                                                strcat(line, next_line);
-                                                next_line = bb_get_chomped_line_from_file(file);
-                                                linenum++;
+                                                if (next_line) {
+                                                        line = realloc(line, strlen(line) + strlen(next_line) + 2);
+                                                        strcat(line, "\n");
+                                                        strcat(line, next_line);
+                                                        next_line = bb_get_chomped_line_from_file(file);
+                                                        linenum++;
+                                                }
                                                 break;
                                         case 'b':
                                                 sed_cmd = branch_to(sed_cmd->label);
@@ -934,9 +974,12 @@ extern int sed_main(int argc, char **argv)
                         case 'n':
                                 be_quiet++;
                                 break;
-                        case 'e':
-                                add_cmd_str(optarg);
+                        case 'e': {
+                                char *str_cmd = strdup(optarg);
+                                add_cmd_str(str_cmd);
+                                free(str_cmd);
                                 break;
+                        }
                         case 'f': 
                                 load_cmd_file(optarg);
                                 break;
@@ -951,7 +994,9 @@ extern int sed_main(int argc, char **argv)
                 if (argv[optind] == NULL)
                         bb_show_usage();
                 else {
-                        add_cmd_str(argv[optind]);
+                        char *str_cmd = strdup(argv[optind]);
+                        add_cmd_str(strdup(str_cmd));
+                        free(str_cmd);
                         optind++;
                 }
         }