Add support for a --one-device flag

src/main.c

@@ -157,7 +157,14 @@ int main(int argc, char **argv) {
             log_debug("searching path %s for %s", paths[i], opts.query);
             symhash = NULL;
             ignores *ig = init_ignore(root_ignores, "", 0);
-            search_dir(ig, base_paths[i], paths[i], 0);
+            struct stat s = {.st_dev = 0};
+            /* The device is ignored if opts.one_dev is false, so it's fine
+             * to leave it at the default 0
+             */
+            if (opts.one_dev && lstat(paths[i], &s) == -1) {
+                log_err("Failed to get device information for path %s. Skipping...", paths[i]);
+            }
+            search_dir(ig, base_paths[i], paths[i], 0, s.st_dev);
             cleanup_ignore(ig);
         }
         pthread_mutex_lock(&work_queue_mtx);

src/options.c

@@ -77,6 +77,7 @@ Search Options:\n\
                           (literal file/directory names also allowed)\n\
      --ignore-dir NAME    Alias for --ignore for compatibility with ack.\n\
   -m --max-count NUM      Skip the rest of a file after NUM matches (Default: 10,000)\n\
+     --one-device         Don't follow links to other devices.\n\
   -p --path-to-agignore STRING\n\
                           Use .agignore file at STRING\n\
   -Q --literal            Don't parse PATTERN as a regular expression\n\
@@ -125,6 +126,7 @@ void init_options(void) {
     opts.color_match = ag_strdup(color_match);
     opts.color_line_number = ag_strdup(color_line_number);
     opts.use_thread_affinity = TRUE;
+    opts.one_dev = FALSE;
 }
 
 void cleanup_options(void) {
@@ -230,6 +232,7 @@ void parse_options(int argc, char **argv, char **base_paths[], char **paths[]) {
         { "nopager", no_argument, NULL, 0 },
         { "null", no_argument, NULL, '0' },
         { "only-matching", no_argument, NULL, 'o' },
+        { "one-device", no_argument, &opts.one_dev, 1 },
         { "pager", required_argument, NULL, 0 },
         { "parallel", no_argument, &opts.parallel, 1 },
         { "passthrough", no_argument, &opts.passthrough, 1 },

src/options.h

@@ -50,6 +50,7 @@ typedef struct {
     int literal_ends_wordchar;
     size_t max_matches_per_file;
     int max_search_depth;
+    int one_dev;
     int only_matching;
     char path_sep;
     char *path_to_agignore;

src/search.c

@@ -378,7 +378,8 @@ static int check_symloop_leave(dirkey_t *dirkey) {
 /* TODO: Append matches to some data structure instead of just printing them out.
  * Then ag can have sweet summaries of matches/files scanned/time/etc.
  */
-void search_dir(ignores *ig, const char *base_path, const char *path, const int depth) {
+void search_dir(ignores *ig, const char *base_path, const char *path, const int depth,
+                dev_t original_dev) {
     struct dirent **dir_list = NULL;
     struct dirent *dir = NULL;
     scandir_baton_t scandir_baton;
@@ -445,6 +446,17 @@ void search_dir(ignores *ig, const char *base_path, const char *path, const int
         queue_item = NULL;
         dir = dir_list[i];
         ag_asprintf(&dir_full_path, "%s/%s", path, dir->d_name);
+        if (opts.one_dev) {
+            struct stat s;
+            if (lstat(dir_full_path, &s) != 0) {
+                log_err("Failed to get device information for %s. Skipping...", dir->d_name);
+                goto cleanup;
+            }
+            if (s.st_dev != original_dev) {
+                log_debug("File %s crosses a device boundary (is probably a mount point.) Skipping...", dir->d_name);
+                goto cleanup;
+            }
+        }
 
         /* If a link points to a directory then we need to treat it as a directory. */
         if (!opts.follow_symlinks && is_symlink(path, dir)) {
@@ -491,7 +503,8 @@ void search_dir(ignores *ig, const char *base_path, const char *path, const int
                 // #else
                 // child_ig = init_ignore(ig, dir->d_name, dir->d_namlen);
                 // #endif
-                search_dir(child_ig, base_path, dir_full_path, depth + 1);
+                search_dir(child_ig, base_path, dir_full_path, depth + 1,
+                           original_dev);
                 cleanup_ignore(child_ig);
             } else {
                 if (opts.max_search_depth == DEFAULT_MAX_SEARCH_DEPTH) {

src/search.h

@@ -72,6 +72,6 @@ void search_file(const char *file_full_path);
 
 void *search_file_worker(void *i);
 
-void search_dir(ignores *ig, const char *base_path, const char *path, const int depth);
+void search_dir(ignores *ig, const char *base_path, const char *path, const int depth, dev_t original_dev);
 
 #endif