tools lib traceevent: Add append() function helper for appending strings

There's several locations that open code realloc and strcat() to append
text to strings. Add an append() function that takes a delimiter and a
string to append to another string.

Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Jaewon Lim <jaewon31.kim@samsung.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kees Kook <keescook@chromium.org>
Cc: linux-mm@kvack.org
Cc: linux-trace-devel@vger.kernel.org
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Link: http://lore.kernel.org/lkml/20200324200956.515118403@goodmis.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/lib/traceevent/event-parse.c b/tools/lib/traceevent/event-parse.c
index e1bd2a9..eec96c3 100644 (file)
--- a/tools/lib/traceevent/event-parse.c
+++ b/tools/lib/traceevent/event-parse.c
@@ -1425,6 +1425,19 @@ static unsigned int type_size(const char *name)
        return 0;
 }
 
+static int append(char **buf, const char *delim, const char *str)
+{
+       char *new_buf;
+
+       new_buf = realloc(*buf, strlen(*buf) + strlen(delim) + strlen(str) + 1);
+       if (!new_buf)
+               return -1;
+       strcat(new_buf, delim);
+       strcat(new_buf, str);
+       *buf = new_buf;
+       return 0;
+}
+
 static int event_read_fields(struct tep_event *event, struct tep_format_field **fields)
 {
        struct tep_format_field *field = NULL;
@@ -1432,6 +1445,7 @@ static int event_read_fields(struct tep_event *event, struct tep_format_field **
        char *token;
        char *last_token;
        int count = 0;
+       int ret;
 
        do {
                unsigned int size_dynamic = 0;
@@ -1490,24 +1504,15 @@ static int event_read_fields(struct tep_event *event, struct tep_format_field **
                                        field->flags |= TEP_FIELD_IS_POINTER;
 
                                if (field->type) {
-                                       char *new_type;
-                                       new_type = realloc(field->type,
-                                                          strlen(field->type) +
-                                                          strlen(last_token) + 2);
-                                       if (!new_type) {
-                                               free(last_token);
-                                               goto fail;
-                                       }
-                                       field->type = new_type;
-                                       strcat(field->type, " ");
-                                       strcat(field->type, last_token);
+                                       ret = append(&field->type, " ", last_token);
                                        free(last_token);
+                                       if (ret < 0)
+                                               goto fail;
                                } else
                                        field->type = last_token;
                                last_token = token;
                                continue;
                        }
-
                        break;
                }
 
@@ -1523,8 +1528,6 @@ static int event_read_fields(struct tep_event *event, struct tep_format_field **
                if (strcmp(token, "[") == 0) {
                        enum tep_event_type last_type = type;
                        char *brackets = token;
-                       char *new_brackets;
-                       int len;
 
                        field->flags |= TEP_FIELD_IS_ARRAY;
 
@@ -1536,29 +1539,27 @@ static int event_read_fields(struct tep_event *event, struct tep_format_field **
                                field->arraylen = 0;
 
                        while (strcmp(token, "]") != 0) {
+                               const char *delim;
+
                                if (last_type == TEP_EVENT_ITEM &&
                                    type == TEP_EVENT_ITEM)
-                                       len = 2;
+                                       delim = " ";
                                else
-                                       len = 1;
+                                       delim = "";
+
                                last_type = type;
 
-                               new_brackets = realloc(brackets,
-                                                      strlen(brackets) +
-                                                      strlen(token) + len);
-                               if (!new_brackets) {
+                               ret = append(&brackets, delim, token);
+                               if (ret < 0) {
                                        free(brackets);
                                        goto fail;
                                }
-                               brackets = new_brackets;
-                               if (len == 2)
-                                       strcat(brackets, " ");
-                               strcat(brackets, token);
                                /* We only care about the last token */
                                field->arraylen = strtoul(token, NULL, 0);
                                free_token(token);
                                type = read_token(&token);
                                if (type == TEP_EVENT_NONE) {
+                                       free(brackets);
                                        do_warning_event(event, "failed to find token");
                                        goto fail;
                                }
@@ -1566,13 +1567,11 @@ static int event_read_fields(struct tep_event *event, struct tep_format_field **
 
                        free_token(token);
 
-                       new_brackets = realloc(brackets, strlen(brackets) + 2);
-                       if (!new_brackets) {
+                       ret = append(&brackets, "", "]");
+                       if (ret < 0) {
                                free(brackets);
                                goto fail;
                        }
-                       brackets = new_brackets;
-                       strcat(brackets, "]");
 
                        /* add brackets to type */
 
@@ -1582,34 +1581,23 @@ static int event_read_fields(struct tep_event *event, struct tep_format_field **
                         * the format: type [] item;
                         */
                        if (type == TEP_EVENT_ITEM) {
-                               char *new_type;
-                               new_type = realloc(field->type,
-                                                  strlen(field->type) +
-                                                  strlen(field->name) +
-                                                  strlen(brackets) + 2);
-                               if (!new_type) {
+                               ret = append(&field->type, " ", field->name);
+                               if (ret < 0) {
                                        free(brackets);
                                        goto fail;
                                }
-                               field->type = new_type;
-                               strcat(field->type, " ");
-                               strcat(field->type, field->name);
+                               ret = append(&field->type, "", brackets);
+
                                size_dynamic = type_size(field->name);
                                free_token(field->name);
-                               strcat(field->type, brackets);
                                field->name = field->alias = token;
                                type = read_token(&token);
                        } else {
-                               char *new_type;
-                               new_type = realloc(field->type,
-                                                  strlen(field->type) +
-                                                  strlen(brackets) + 1);
-                               if (!new_type) {
+                               ret = append(&field->type, "", brackets);
+                               if (ret < 0) {
                                        free(brackets);
                                        goto fail;
                                }
-                               field->type = new_type;
-                               strcat(field->type, brackets);
                        }
                        free(brackets);
                }
@@ -2046,19 +2034,16 @@ process_op(struct tep_event *event, struct tep_print_arg *arg, char **tok)
                /* could just be a type pointer */
                if ((strcmp(arg->op.op, "*") == 0) &&
                    type == TEP_EVENT_DELIM && (strcmp(token, ")") == 0)) {
-                       char *new_atom;
+                       int ret;
 
                        if (left->type != TEP_PRINT_ATOM) {
                                do_warning_event(event, "bad pointer type");
                                goto out_free;
                        }
-                       new_atom = realloc(left->atom.atom,
-                                           strlen(left->atom.atom) + 3);
-                       if (!new_atom)
+                       ret = append(&left->atom.atom, " ", "*");
+                       if (ret < 0)
                                goto out_warn_free;
 
-                       left->atom.atom = new_atom;
-                       strcat(left->atom.atom, " *");
                        free(arg->op.op);
                        *arg = *left;
                        free(left);
@@ -3151,18 +3136,15 @@ process_arg_token(struct tep_event *event, struct tep_print_arg *arg,
                }
                /* atoms can be more than one token long */
                while (type == TEP_EVENT_ITEM) {
-                       char *new_atom;
-                       new_atom = realloc(atom,
-                                          strlen(atom) + strlen(token) + 2);
-                       if (!new_atom) {
+                       int ret;
+
+                       ret = append(&atom, " ", token);
+                       if (ret < 0) {
                                free(atom);
                                *tok = NULL;
                                free_token(token);
                                return TEP_EVENT_ERROR;
                        }
-                       atom = new_atom;
-                       strcat(atom, " ");
-                       strcat(atom, token);
                        free_token(token);
                        type = read_token_item(&token);
                }