Command-line utility: avoid NULL dereference when displaying string config settings

[browser-switch] / config-ui / browser-switchboard-config.c

diff --git a/config-ui/browser-switchboard-config.c b/config-ui/browser-switchboard-config.c
index c14b80f..ec1e509 100644 (file)
--- a/config-ui/browser-switchboard-config.c
+++ b/config-ui/browser-switchboard-config.c
@@ -22,6 +22,7 @@
 
 
 #include <stdlib.h>
+#include <stddef.h>
 #include <string.h>
 #include <stdio.h>
 #include <getopt.h>
@@ -32,8 +33,8 @@ extern struct swb_config_option swb_config_options[];
 
 static int get_config_value(char *name) {
        struct swb_config cfg;
-       int i;
-       struct swb_config_option optinfo;
+       struct swb_config_option *optinfo;
+       ptrdiff_t i;
        int retval = 1;
 
        swb_config_init(&cfg);
@@ -41,14 +42,15 @@ static int get_config_value(char *name) {
        if (!swb_config_load(&cfg))
                return 1;
 
-       for (i = 0; swb_config_options[i].name; ++i) {
-               optinfo = swb_config_options[i];
-               if (strcmp(name, optinfo.name))
+       for (optinfo = swb_config_options; optinfo->name; ++optinfo) {
+               if (strcmp(name, optinfo->name))
                        continue;
 
-               switch (optinfo.type) {
+               i = optinfo - swb_config_options;
+               switch (optinfo->type) {
                  case SWB_CONFIG_OPT_STRING:
-                       printf("%s\n", *(char **)cfg.entries[i]);
+                       if (*(char **)cfg.entries[i])
+                               printf("%s\n", *(char **)cfg.entries[i]);
                        break;
                  case SWB_CONFIG_OPT_INT:
                        printf("%d\n", *(int *)cfg.entries[i]);
@@ -67,8 +69,8 @@ static int get_config_value(char *name) {
 
 static int set_config_value(char *name, char *value) {
        struct swb_config cfg;
-       int i;
-       struct swb_config_option optinfo;
+       struct swb_config_option *optinfo;
+       ptrdiff_t i;
        int retval = 1;
 
        swb_config_init(&cfg);
@@ -76,39 +78,39 @@ static int set_config_value(char *name, char *value) {
        if (!swb_config_load(&cfg))
                return 1;
 
-       for (i = 0; swb_config_options[i].name; ++i) {
-               optinfo = swb_config_options[i];
-               if (strcmp(name, optinfo.name))
+       for (optinfo = swb_config_options; optinfo->name; ++optinfo) {
+               if (strcmp(name, optinfo->name))
                        continue;
 
-               switch (optinfo.type) {
+               i = optinfo - swb_config_options;
+               switch (optinfo->type) {
                  case SWB_CONFIG_OPT_STRING:
                        /* Free any existing string */
-                       if (cfg.flags & optinfo.set_mask)
+                       if (cfg.flags & optinfo->set_mask)
                                free(*(char **)cfg.entries[i]);
 
                        if (strlen(value) == 0) {
                                /* If the new value is empty, clear the config
                                   setting */
                                *(char **)cfg.entries[i] = NULL;
-                               cfg.flags &= ~optinfo.set_mask;
+                               cfg.flags &= ~optinfo->set_mask;
                        } else {
                                /* Make a copy of the string -- it's not safe
                                   to free value, which comes from argv */
                                if (!(*(char **)cfg.entries[i] =
                                      strdup(value)))
                                        exit(1);
-                               cfg.flags |= optinfo.set_mask;
+                               cfg.flags |= optinfo->set_mask;
                        }
                        break;
                  case SWB_CONFIG_OPT_INT:
                        if (strlen(value) == 0) {
                                /* If the new value is empty, clear the config
                                   setting */
-                               cfg.flags &= ~optinfo.set_mask;
+                               cfg.flags &= ~optinfo->set_mask;
                        } else {
                                *(int *)cfg.entries[i] = atoi(value);
-                               cfg.flags |= optinfo.set_mask;
+                               cfg.flags |= optinfo->set_mask;
                        }
                        break;
                }