Merge pull request #134 from jhunkeler/sprintf-to-snprintf

String safety

8 files changed, 83 insertions, 68 deletions

diff --git a/src/cli/stasis/args.c b/src/cli/stasis/args.c
index dbc9c2f..98b4479 100644
--- a/src/cli/stasis/args.c
+++ b/src/cli/stasis/args.c
@@ -85,28 +85,30 @@ void usage(char *progname) {
     int width = get_option_max_width(long_options);
     for (int x = 0; long_options[x].name != 0; x++) {
         char tmp[STASIS_NAME_MAX] = {0};
-        char output[sizeof(tmp)] = {0};
+        char output[STASIS_NAME_MAX] = {0};
         char opt_long[50] = {0};        // --? [ARG]?
         char opt_short[50] = {0};        // -? [ARG]?
 
-        strcat(opt_long, "--");
-        strcat(opt_long, long_options[x].name);
+        strncat(opt_long, "--", sizeof(opt_long) - strlen(opt_long) - 1);
+        strncat(opt_long, long_options[x].name, sizeof(opt_long) - strlen(opt_long) - 1);
         if (long_options[x].has_arg) {
-            strcat(opt_long, " ARG");
+            strncat(opt_long, " ARG", sizeof(opt_long) - strlen(opt_long) - 1);
         }
 
         if (long_options[x].val <= 'z') {
-            strcat(opt_short, "-");
+            strncat(opt_short, "-", sizeof(opt_short) - strlen(opt_short) - 1);
             opt_short[1] = (char) long_options[x].val;
             if (long_options[x].has_arg) {
-                strcat(opt_short, " ARG");
+                strncat(opt_short, " ARG", sizeof(opt_short) - strlen(opt_short) - 1);
             }
         } else {
-            strcat(opt_short, "  ");
+            strncat(opt_short, "  ", sizeof(opt_short) - strlen(opt_short) - 1);
         }
 
-        sprintf(tmp, "  %%-%ds\t%%s\t\t%%s", width + 4);
-        sprintf(output, tmp, opt_long, opt_short, long_options_help[x]);
+        const char *opt_fmt = "  %%-%ds\t%%s\t\t%%s";
+        size_t opt_fmt_len = snprintf(NULL, 0, opt_fmt, width);
+        snprintf(tmp, sizeof(tmp) - opt_fmt_len, opt_fmt, width + 4);
+        snprintf(output, sizeof(output), tmp, opt_long, opt_short, long_options_help[x]);
         puts(output);
     }
 }
diff --git a/src/cli/stasis/stasis_main.c b/src/cli/stasis/stasis_main.c
index 44efc4a..328d825 100644
--- a/src/cli/stasis/stasis_main.c
+++ b/src/cli/stasis/stasis_main.c
@@ -45,7 +45,7 @@ static void configure_stasis_ini(struct Delivery *ctx, char **config_input) {
     if (!*config_input) {
         SYSDEBUG("%s", "No configuration passed by argument. Using basic config.");
         char cfgfile[PATH_MAX * 2];
-        sprintf(cfgfile, "%s/%s", globals.sysconfdir, "stasis.ini");
+        snprintf(cfgfile, sizeof(cfgfile), "%s/%s", globals.sysconfdir, "stasis.ini");
         SYSDEBUG("cfgfile: %s", cfgfile);
         if (!access(cfgfile, F_OK | R_OK)) {
             *config_input = strdup(cfgfile);
@@ -161,9 +161,9 @@ static void check_conda_prefix_length(const struct Delivery *ctx) {
     }
 }
 
-static void setup_conda(struct Delivery *ctx, char *installer_url) {
+static void setup_conda(struct Delivery *ctx, char *installer_url, const size_t maxlen) {
     msg(STASIS_MSG_L1, "Conda setup\n");
-    delivery_get_conda_installer_url(ctx, installer_url);
+    delivery_get_conda_installer_url(ctx, installer_url, maxlen);
     msg(STASIS_MSG_L2, "Downloading: %s\n", installer_url);
     if (delivery_get_conda_installer(ctx, installer_url)) {
         msg(STASIS_MSG_ERROR, "download failed: %s\n", installer_url);
@@ -429,7 +429,7 @@ static void build_docker(struct Delivery *ctx, const int disabled) {
             msg(STASIS_MSG_L1 | STASIS_MSG_WARN, "Docker image building is disabled by CLI argument\n");
         } else {
             char dockerfile[PATH_MAX] = {0};
-            sprintf(dockerfile, "%s/%s", ctx->storage.build_docker_dir, "Dockerfile");
+            snprintf(dockerfile, sizeof(dockerfile), "%s/%s", ctx->storage.build_docker_dir, "Dockerfile");
             if (globals.enable_docker) {
                 if (!access(dockerfile, F_OK)) {
                     msg(STASIS_MSG_L1, "Building Docker image\n");
@@ -461,7 +461,7 @@ static void generate_release(struct Delivery *ctx, char *env_name, char *env_nam
     delivery_export(ctx, (char *[]) {env_name, env_name_testing, NULL});
 
     char specfile[PATH_MAX];
-    sprintf(specfile, "%s/%s.yml", ctx->storage.delivery_dir, env_name);
+    snprintf(specfile, sizeof(specfile), "%s/%s.yml", ctx->storage.delivery_dir, env_name);
 
     delivery_rewrite_stage1(ctx, specfile);
     build_docker(ctx, disable_docker);
@@ -532,7 +532,7 @@ int main(int argc, char *argv[]) {
                 globals.continue_on_error = true;
                 break;
             case 'p':
-                strcpy(python_override_version, optarg);
+                strncpy(python_override_version, optarg, sizeof(python_override_version) - 1);
                 break;
             case 'l':
                 globals.cpu_limit = strtol(optarg, NULL, 10);
@@ -652,9 +652,9 @@ int main(int argc, char *argv[]) {
     configure_jfrog_cli(&ctx);
 
     runtime_apply(ctx.runtime.environ);
-    strcpy(env_name, ctx.info.release_name);
-    strcpy(env_name_testing, env_name);
-    strcat(env_name_testing, "-test");
+    strncpy(env_name, ctx.info.release_name, sizeof(env_name) - 1);
+    strncpy(env_name_testing, env_name, sizeof(env_name_testing) - 1);
+    strncat(env_name_testing, "-test", sizeof(env_name_testing) - strlen(env_name_testing) - 1);
     char *envs[] = {
         "release", env_name,
         "testing", env_name_testing,
@@ -666,7 +666,7 @@ int main(int argc, char *argv[]) {
 
     check_conda_install_prefix(&ctx);
     check_conda_prefix_length(&ctx);
-    setup_conda(&ctx, installer_url);
+    setup_conda(&ctx, installer_url, sizeof(installer_url));
     configure_conda_base(&ctx, envs);
     configure_conda_purge(&ctx, envs);
     setup_activate_test_env(&ctx, env_name_testing);
diff --git a/src/cli/stasis_indexer/args.c b/src/cli/stasis_indexer/args.c
index 2d92ab0..8c9d3fe 100644
--- a/src/cli/stasis_indexer/args.c
+++ b/src/cli/stasis_indexer/args.c
@@ -30,7 +30,7 @@ void usage(char *name) {
 
     for (int i = 0; i < maxopts - 1; i++) {
         char line[255] = {0};
-        sprintf(line, "  --%s  -%c  %-20s", long_options[i].name, long_options[i].val, long_options_help[i]);
+        snprintf(line, sizeof(line), "  --%s  -%c  %-20s", long_options[i].name, long_options[i].val, long_options_help[i]);
         puts(line);
     }
 
diff --git a/src/cli/stasis_indexer/helpers.c b/src/cli/stasis_indexer/helpers.c
index 6dc653d..0debfe4 100644
--- a/src/cli/stasis_indexer/helpers.c
+++ b/src/cli/stasis_indexer/helpers.c
@@ -96,44 +96,44 @@ int pandoc_exec(const char *in_file, const char *out_file, const char *css_file,
     if (!get_pandoc_version(&pandoc_version)) {
         // < 2.19
         if (pandoc_version < 0x02130000) {
-            strcat(pandoc_versioned_args, "--self-contained ");
+            strncat(pandoc_versioned_args, "--self-contained ", sizeof(pandoc_versioned_args) - strlen(pandoc_versioned_args) - 1);
         } else {
             // >= 2.19
-            strcat(pandoc_versioned_args, "--embed-resources ");
+            strncat(pandoc_versioned_args, "--embed-resources ", sizeof(pandoc_versioned_args) - strlen(pandoc_versioned_args) - 1);
         }
 
         // >= 1.15.0.4
         if (pandoc_version >= 0x010f0004) {
-            strcat(pandoc_versioned_args, "--standalone ");
+            strncat(pandoc_versioned_args, "--standalone ", sizeof(pandoc_versioned_args) - strlen(pandoc_versioned_args) - 1);
         }
 
         // >= 1.10.0.1
         if (pandoc_version >= 0x010a0001) {
-            strcat(pandoc_versioned_args, "-f gfm+autolink_bare_uris ");
+            strncat(pandoc_versioned_args, "-f gfm+autolink_bare_uris ", sizeof(pandoc_versioned_args) - strlen(pandoc_versioned_args) - 1);
         }
 
         // > 3.1.9
         if (pandoc_version > 0x03010900) {
-            strcat(pandoc_versioned_args, "-f gfm+alerts ");
+            strncat(pandoc_versioned_args, "-f gfm+alerts ", sizeof(pandoc_versioned_args) - strlen(pandoc_versioned_args) - 1);
         }
     }
 
     // Converts a markdown file to html
     char cmd[STASIS_BUFSIZ] = {0};
-    strcpy(cmd, "pandoc ");
-    strcat(cmd, pandoc_versioned_args);
+    strncpy(cmd, "pandoc ", sizeof(cmd) - 1);
+    strncat(cmd, pandoc_versioned_args, sizeof(cmd) - strlen(cmd) - 1);
     if (css_file && strlen(css_file)) {
-        strcat(cmd, "--css ");
-        strcat(cmd, css_file);
+        strncat(cmd, "--css ", sizeof(cmd) - strlen(cmd) - 1);
+        strncat(cmd, css_file, sizeof(cmd) - strlen(cmd) - 1);
     }
-    strcat(cmd, " ");
-    strcat(cmd, "--metadata title=\"");
-    strcat(cmd, title);
-    strcat(cmd, "\" ");
-    strcat(cmd, "-o ");
-    strcat(cmd, out_file);
-    strcat(cmd, " ");
-    strcat(cmd, in_file);
+    strncat(cmd, " ", sizeof(cmd) - strlen(cmd) - 1);
+    strncat(cmd, "--metadata title=\"", sizeof(cmd) - strlen(cmd) - 1);
+    strncat(cmd, title, sizeof(cmd) - strlen(cmd) - 1);
+    strncat(cmd, "\" ", sizeof(cmd) - strlen(cmd) - 1);
+    strncat(cmd, "-o ", sizeof(cmd) - strlen(cmd) - 1);
+    strncat(cmd, out_file, sizeof(cmd) - strlen(cmd) - 1);
+    strncat(cmd, " ", sizeof(cmd) - strlen(cmd) - 1);
+    strncat(cmd, in_file, sizeof(cmd) - strlen(cmd) - 1);
 
     if (globals.verbose) {
         puts(cmd);
@@ -243,7 +243,15 @@ int get_files(struct StrList **out, const char *path, const char *pattern, ...)
     va_list args;
     va_start(args, pattern);
     char userpattern[PATH_MAX] = {0};
-    vsprintf(userpattern, pattern, args);
+    const int len = vsnprintf(userpattern, sizeof(userpattern), pattern, args);
+    if (len < 0) {
+        SYSERROR("%s", "vsnprintf failed\n");
+        va_end(args);
+        return -1;
+    }
+    if ((size_t) len > sizeof(userpattern)) {
+        fprintf(stderr, "WARNING: %s: userpattern truncated!\n", __FUNCTION__);
+    }
     va_end(args);
     if (!strlen(userpattern)) {
         userpattern[0] = '*';
@@ -377,8 +385,8 @@ int write_manifest(const char *path, char **exclude_path, FILE *fp) {
         }
         char filepath[PATH_MAX] = {0};
         strncpy(filepath, path, PATH_MAX - 1);
-        strcat(filepath, "/");
-        strcat(filepath, rec->d_name);
+        strncat(filepath, "/", sizeof(filepath) - strlen(filepath) - 1);
+        strncat(filepath, rec->d_name, sizeof(filepath) - strlen(filepath) - 1);
         if (rec->d_type == DT_DIR) {
             write_manifest(filepath, exclude_path, fp);
             continue;
diff --git a/src/cli/stasis_indexer/junitxml_report.c b/src/cli/stasis_indexer/junitxml_report.c
index 21cf729..d30ee09 100644
--- a/src/cli/stasis_indexer/junitxml_report.c
+++ b/src/cli/stasis_indexer/junitxml_report.c
@@ -98,7 +98,7 @@ static int write_report_output(struct Delivery *ctx, FILE *destfp, const char *x
 
 int indexer_junitxml_report(struct Delivery **ctx, const size_t nelem) {
     char indexfile[PATH_MAX] = {0};
-    sprintf(indexfile, "%s/README.md", (*ctx)->storage.results_dir);
+    snprintf(indexfile, sizeof(indexfile), "%s/README.md", (*ctx)->storage.results_dir);
 
     struct StrList *file_listing = listdir((*ctx)->storage.results_dir);
     if (!file_listing) {
@@ -117,7 +117,7 @@ int indexer_junitxml_report(struct Delivery **ctx, const size_t nelem) {
         int current_rc = (*ctx)->meta.rc;
         for (size_t d = 0; d < nelem; d++) {
             char pattern[PATH_MAX] = {0};
-            snprintf(pattern, sizeof(pattern) - 1, "*%s*", ctx[d]->info.release_name);
+            snprintf(pattern, sizeof(pattern), "*%s*", ctx[d]->info.release_name);
 
             // if the result directory contains tests for this release name, print them
             if (!is_file_in_listing(file_listing, pattern)) {
diff --git a/src/cli/stasis_indexer/readmes.c b/src/cli/stasis_indexer/readmes.c
index edc6312..91c936f 100644
--- a/src/cli/stasis_indexer/readmes.c
+++ b/src/cli/stasis_indexer/readmes.c
@@ -12,7 +12,7 @@ int indexer_readmes(struct Delivery **ctx, const size_t nelem) {
     }
 
     char indexfile[PATH_MAX] = {0};
-    sprintf(indexfile, "%s/README.md", (*ctx)->storage.delivery_dir);
+    snprintf(indexfile, sizeof(indexfile), "%s/README.md", (*ctx)->storage.delivery_dir);
 
     FILE *indexfp = fopen(indexfile, "w+");
     if (!indexfp) {
@@ -52,10 +52,10 @@ int indexer_readmes(struct Delivery **ctx, const size_t nelem) {
                 if (!latest_deliveries[i]->meta.name) {
                     continue;
                 }
-                sprintf(link_name, "latest-py%s-%s-%s.yml", latest_deliveries[i]->meta.python_compact, latest_deliveries[i]->system.platform[DELIVERY_PLATFORM_RELEASE], latest_deliveries[i]->system.arch);
-                sprintf(readme_name, "README-py%s-%s-%s.md", latest_deliveries[i]->meta.python_compact, latest_deliveries[i]->system.platform[DELIVERY_PLATFORM_RELEASE], latest_deliveries[i]->system.arch);
-                sprintf(conf_name, "%s.ini", latest_deliveries[i]->info.release_name);
-                sprintf(conf_name_relative, "../config/%s.ini", latest_deliveries[i]->info.release_name);
+                snprintf(link_name, sizeof(link_name), "latest-py%s-%s-%s.yml", latest_deliveries[i]->meta.python_compact, latest_deliveries[i]->system.platform[DELIVERY_PLATFORM_RELEASE], latest_deliveries[i]->system.arch);
+                snprintf(readme_name, sizeof(readme_name), "README-py%s-%s-%s.md", latest_deliveries[i]->meta.python_compact, latest_deliveries[i]->system.platform[DELIVERY_PLATFORM_RELEASE], latest_deliveries[i]->system.arch);
+                snprintf(conf_name, sizeof(conf_name), "%s.ini", latest_deliveries[i]->info.release_name);
+                snprintf(conf_name_relative, sizeof(conf_name_relative), "../config/%s.ini", latest_deliveries[i]->info.release_name);
                 if (strstr(link_name, platform) && strstr(link_name, arch)) {
                     fprintf(indexfp, "- Python %s\n", latest_deliveries[i]->meta.python);
                     fprintf(indexfp, "  - Info: [README](%s)\n", readme_name);
diff --git a/src/cli/stasis_indexer/stasis_indexer_main.c b/src/cli/stasis_indexer/stasis_indexer_main.c
index 840e897..d475c15 100644
--- a/src/cli/stasis_indexer/stasis_indexer_main.c
+++ b/src/cli/stasis_indexer/stasis_indexer_main.c
@@ -13,9 +13,9 @@ int indexer_combine_rootdirs(const char *dest, char **rootdirs, const size_t roo
     char destdir_with_output[PATH_MAX] = {0};
     char *destdir = destdir_bare;
 
-    strcpy(destdir_bare, dest);
-    strcpy(destdir_with_output, dest);
-    strcat(destdir_with_output, "/output");
+    strncpy(destdir_bare, dest, sizeof(destdir_bare) - 1);
+    strncpy(destdir_with_output, dest, sizeof(destdir_with_output) - 1);
+    strncat(destdir_with_output, "/output", sizeof(destdir_with_output) - strlen(destdir_with_output) - 1);
 
     if (!access(destdir_with_output, F_OK)) {
         destdir = destdir_with_output;
@@ -26,9 +26,9 @@ int indexer_combine_rootdirs(const char *dest, char **rootdirs, const size_t roo
         char srcdir_bare[PATH_MAX] = {0};
         char srcdir_with_output[PATH_MAX] = {0};
         char *srcdir = srcdir_bare;
-        strcpy(srcdir_bare, rootdirs[i]);
-        strcpy(srcdir_with_output, rootdirs[i]);
-        strcat(srcdir_with_output, "/output");
+        strncpy(srcdir_bare, rootdirs[i], sizeof(srcdir_bare) - 1);
+        strncpy(srcdir_with_output, rootdirs[i], sizeof(srcdir_with_output) - 1);
+        strncat(srcdir_with_output, "/output", sizeof(srcdir_with_output) - strlen(srcdir_with_output) - 1);
 
         if (access(srcdir_bare, F_OK)) {
             fprintf(stderr, "%s does not exist\n", srcdir_bare);
@@ -80,11 +80,11 @@ int indexer_symlinks(struct Delivery **ctx, const size_t nelem) {
             if (!data[i]->meta.name) {
                 continue;
             }
-            sprintf(link_name_spec, "latest-py%s-%s-%s.yml", data[i]->meta.python_compact, data[i]->system.platform[DELIVERY_PLATFORM_RELEASE], data[i]->system.arch);
-            sprintf(file_name_spec, "%s.yml", data[i]->info.release_name);
+            snprintf(link_name_spec, sizeof(link_name_spec), "latest-py%s-%s-%s.yml", data[i]->meta.python_compact, data[i]->system.platform[DELIVERY_PLATFORM_RELEASE], data[i]->system.arch);
+            snprintf(file_name_spec, sizeof(file_name_spec), "%s.yml", data[i]->info.release_name);
 
-            sprintf(link_name_readme, "README-py%s-%s-%s.md", data[i]->meta.python_compact, data[i]->system.platform[DELIVERY_PLATFORM_RELEASE], data[i]->system.arch);
-            sprintf(file_name_readme, "README-%s.md", data[i]->info.release_name);
+            snprintf(link_name_readme, sizeof(link_name_readme), "README-py%s-%s-%s.md", data[i]->meta.python_compact, data[i]->system.platform[DELIVERY_PLATFORM_RELEASE], data[i]->system.arch);
+            snprintf(file_name_readme, sizeof(file_name_readme), "README-%s.md", data[i]->info.release_name);
 
             if (!access(link_name_spec, F_OK)) {
                 if (unlink(link_name_spec)) {
@@ -151,7 +151,7 @@ void indexer_init_dirs(struct Delivery *ctx, const char *workdir) {
 
     char newpath[PATH_MAX] = {0};
     if (getenv("PATH")) {
-        sprintf(newpath, "%s/bin:%s", ctx->storage.tools_dir, getenv("PATH"));
+        snprintf(newpath, sizeof(newpath), "%s/bin:%s", ctx->storage.tools_dir, getenv("PATH"));
         setenv("PATH", newpath, 1);
     } else {
         SYSERROR("%s", "environment variable PATH is undefined. Unable to continue.");
@@ -261,11 +261,11 @@ int main(const int argc, char *argv[]) {
     char workdir_template[PATH_MAX] = {0};
     const char *system_tmp = getenv("TMPDIR");
     if (system_tmp) {
-        strcat(workdir_template, system_tmp);
+        strncat(workdir_template, system_tmp, sizeof(workdir_template) - strlen(workdir_template) - 1);
     } else {
-        strcat(workdir_template, "/tmp");
+        strncat(workdir_template, "/tmp", sizeof(workdir_template) - strlen(workdir_template) - 1);
     }
-    strcat(workdir_template, "/stasis-combine.XXXXXX");
+    strncat(workdir_template, "/stasis-combine.XXXXXX", sizeof(workdir_template) - strlen(workdir_template) - 1);
     char *workdir = mkdtemp(workdir_template);
     if (!workdir) {
         SYSERROR("Unable to create temporary directory: %s", workdir_template);
@@ -320,6 +320,11 @@ int main(const int argc, char *argv[]) {
     msg(STASIS_MSG_L1, "Loading metadata\n");
     struct StrList *metafiles = NULL;
     get_files(&metafiles, ctx.storage.meta_dir, "*.stasis");
+    if (!metafiles || !strlist_count(metafiles)) {
+        SYSERROR("%s: No metadata!", ctx.storage.meta_dir);
+        delivery_free(&ctx);
+        exit(1);
+    }
     strlist_sort(metafiles, STASIS_SORT_LEN_ASCENDING);
 
     struct Delivery **local = calloc(strlist_count(metafiles) + 1, sizeof(*local));
@@ -411,7 +416,7 @@ int main(const int argc, char *argv[]) {
 
     msg(STASIS_MSG_L1, "Copying indexed delivery to '%s'\n", destdir);
     char cmd[PATH_MAX] = {0};
-    sprintf(cmd, "rsync -ah%s --delete --exclude 'tmp/' --exclude 'tools/' '%s/' '%s/'", globals.verbose ? "v" : "q", workdir, destdir);
+    snprintf(cmd, sizeof(cmd), "rsync -ah%s --delete --exclude 'tmp/' --exclude 'tools/' '%s/' '%s/'", globals.verbose ? "v" : "q", workdir, destdir);
     guard_free(destdir);
 
     if (globals.verbose) {
diff --git a/src/cli/stasis_indexer/website.c b/src/cli/stasis_indexer/website.c
index 966391e..8a5126d 100644
--- a/src/cli/stasis_indexer/website.c
+++ b/src/cli/stasis_indexer/website.c
@@ -8,7 +8,7 @@ int indexer_make_website(struct Delivery **ctx) {
         return -1;
     }
 
-    sprintf(css_filename, "%s/%s", globals.sysconfdir, "stasis_pandoc.css");
+    snprintf(css_filename, PATH_MAX, "%s/%s", globals.sysconfdir, "stasis_pandoc.css");
     const int have_css = access(css_filename, F_OK | R_OK) == 0;
 
     struct StrList *dirs = strlist_init();
@@ -29,14 +29,14 @@ int indexer_make_website(struct Delivery **ctx) {
             char *filename = path_basename(strlist_item(inputs, x));
             char fullpath_src[PATH_MAX] = {0};
             char fullpath_dest[PATH_MAX] = {0};
-            sprintf(fullpath_src, "%s/%s", root, filename);
+            snprintf(fullpath_src, sizeof(fullpath_src), "%s/%s", root, filename);
             if (access(fullpath_src, F_OK)) {
                 continue;
             }
 
             // Replace *.md extension with *.html.
-            strcpy(fullpath_dest, fullpath_src);
-            gen_file_extension_str(fullpath_dest, ".html");
+            strncpy(fullpath_dest, fullpath_src, sizeof(fullpath_dest) - 1);
+            gen_file_extension_str(fullpath_dest, sizeof(fullpath_dest), ".html");
 
             // Convert markdown to html
             if (pandoc_exec(fullpath_src, fullpath_dest, have_css ? css_filename : NULL, "STASIS")) {
@@ -52,8 +52,8 @@ int indexer_make_website(struct Delivery **ctx) {
             if (!strcmp(filename, "README.md")) {
                 char link_from[PATH_MAX] = {0};
                 char link_dest[PATH_MAX] = {0};
-                strcpy(link_from, "README.html");
-                sprintf(link_dest, "%s/%s", root, "index.html");
+                strncpy(link_from, "README.html", sizeof(link_from) - 1);
+                snprintf(link_dest, sizeof(link_dest), "%s/%s", root, "index.html");
                 if (symlink(link_from, link_dest)) {
                     SYSERROR("Warning: symlink(%s, %s) failed: %s", link_from, link_dest, strerror(errno));
                 }