conf: Search included files under user specified configuration directories

Users can include file by giving a relative path or just a file name via
alsaconf syntax <xxx>. ALSA conf will search the file in top configuration
directory and additional configuration directories defined by users via
alsaconf syntax <searchdir:xxx>.

ALSA conf will search and open an included file in the following order
of priority:

1. directly open the file by its name;
2. search for the file name in top config direcotry "/usr/share/alsa/";
3. search for the file name in additional configuration directories
   specified by users, via alsaconf syntax
   <searchdir:relative-path/to/user/share/alsa>;
   These directories will be searched in the same order as their
   definition.

The configuration directories defined by a file will only be used to
search the files included by this file.

Signed-off-by: Mengdong Lin <mengdong.lin@linux.intel.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

diff --git a/src/conf.c b/src/conf.c
index a516611427acda7406e4936b8cb5ef06f87f5b9a..fbd90ac277caae30e633ed572577419e07863acf 100644 (file)
--- a/src/conf.c
+++ b/src/conf.c
@@ -456,6 +456,18 @@ struct filedesc {
        snd_input_t *in;
        unsigned int line, column;
        struct filedesc *next;
+
+       /* list of the include paths (configuration directories),
+        * defined by <searchdir:relative-path/to/top-alsa-conf-dir>,
+        * for searching its included files.
+        */
+       struct list_head include_paths;
+};
+
+/* path to search included files */
+struct include_path {
+       char *dir;
+       struct list_head list;
 };
 
 #define LOCAL_ERROR                    (-0x68000000)
@@ -501,6 +513,108 @@ static inline void snd_config_unlock(void) { }
 
 #endif
 
+/*
+ * Add a diretory to the paths to search included files.
+ * param fd -  File object that owns these paths to search files included by it.
+ * param dir - Path of the directory to add. Allocated externally and need to
+*              be freed manually later.
+ * return - Zero if successful, otherwise a negative error code.
+ *
+ * The direcotry should be a subdiretory of top configuration directory
+ * "/usr/share/alsa/".
+ */
+static int add_include_path(struct filedesc *fd, char *dir)
+{
+       struct include_path *path;
+
+       path = calloc(1, sizeof(*path));
+       if (!path)
+               return -ENOMEM;
+
+       path->dir = dir;
+       list_add_tail(&path->list, &fd->include_paths);
+       return 0;
+}
+
+/*
+ * Free all include paths of a file descriptor.
+ * param fd - File object that owns these paths to search files included by it.
+ */
+static void free_include_paths(struct filedesc *fd)
+{
+       struct list_head *pos, *npos, *base;
+       struct include_path *path;
+
+       base = &fd->include_paths;
+       list_for_each_safe(pos, npos, base) {
+               path = list_entry(pos, struct include_path, list);
+               list_del(&path->list);
+               if (path->dir)
+                       free(path->dir);
+               free(path);
+       }
+}
+
+/*
+ * Search and open a file, and creates a new input object reading from the file.
+ * param inputp - The functions puts the pointer to the new input object
+ *               at the address specified by \p inputp.
+ * param file - Name of the configuration file.
+ * param include_paths - Optional, addtional directories to search the file.
+ * return - Zero if successful, otherwise a negative error code.
+ *
+ * This function will search and open the file in the following order
+ * of priority:
+ * 1. directly open the file by its name;
+ * 2. search for the file name in top configuration directory
+ *     "/usr/share/alsa/";
+ * 3. search for the file name in in additional configuration directories
+ *     specified by users, via alsaconf syntax
+ *     <searchdir:relative-path/to/user/share/alsa>;
+ *     These directories should be subdirectories of /usr/share/alsa.
+ */
+static int input_stdio_open(snd_input_t **inputp, const char *file,
+                           struct list_head *include_paths)
+{
+       struct list_head *pos, *base;
+       struct include_path *path;
+       char full_path[PATH_MAX + 1];
+       int err = 0;
+
+       err = snd_input_stdio_open(inputp, file, "r");
+       if (err == 0)
+               goto out;
+
+       if (file[0] == '/') /* not search file with absolute path */
+               return err;
+
+       /* search file in top configuration directory /usr/share/alsa */
+       snprintf(full_path, PATH_MAX, "%s/%s", ALSA_CONFIG_DIR, file);
+       err = snd_input_stdio_open(inputp, full_path, "r");
+       if (err == 0)
+               goto out;
+
+       /* search file in user specified include paths. These directories
+        * are subdirectories of /usr/share/alsa.
+        */
+       if (include_paths) {
+               base = include_paths;
+               list_for_each(pos, base) {
+                       path = list_entry(pos, struct include_path, list);
+                       if (!path->dir)
+                               continue;
+
+                       snprintf(full_path, PATH_MAX, "%s/%s", path->dir, file);
+                       err = snd_input_stdio_open(inputp, full_path, "r");
+                       if (err == 0)
+                               goto out;
+               }
+       }
+
+out:
+       return err;
+}
+
 static int safe_strtoll(const char *str, long long *val)
 {
        long long v;
@@ -629,10 +743,44 @@ static int get_char_skip_comments(input_t *input)
                        char *str;
                        snd_input_t *in;
                        struct filedesc *fd;
+                       DIR *dirp;
                        int err = get_delimstring(&str, '>', input);
                        if (err < 0)
                                return err;
+
+                       if (!strncmp(str, "searchdir:", 10)) {
+                               /* directory to search included files */
+                               char *tmp;
+
+                               tmp = malloc(strlen(ALSA_CONFIG_DIR) + 1
+                                            + strlen(str + 10) + 1);
+                               if (tmp == NULL) {
+                                       free(str);
+                                       return -ENOMEM;
+                               }
+                               sprintf(tmp, ALSA_CONFIG_DIR "/%s", str + 10);
+                               free(str);
+                               str = tmp;
+
+                               dirp = opendir(str);
+                               if (!dirp) {
+                                       SNDERR("Invalid search dir %s", str);
+                                       free(str);
+                                       return -EINVAL;
+                               }
+                               closedir(dirp);
+
+                               err = add_include_path(input->current, str);
+                               if (err < 0) {
+                                       SNDERR("Cannot add search dir %s", str);
+                                       free(str);
+                                       return err;
+                               }
+                               continue;
+                       }
+
                        if (!strncmp(str, "confdir:", 8)) {
+                               /* file in the specified directory */
                                char *tmp = malloc(strlen(ALSA_CONFIG_DIR) + 1 + strlen(str + 8) + 1);
                                if (tmp == NULL) {
                                        free(str);
@@ -641,8 +789,12 @@ static int get_char_skip_comments(input_t *input)
                                sprintf(tmp, ALSA_CONFIG_DIR "/%s", str + 8);
                                free(str);
                                str = tmp;
+                               err = snd_input_stdio_open(&in, str, "r");
+                       } else { /* absolute or relative file path */
+                               err = input_stdio_open(&in, str,
+                                               &input->current->include_paths);
                        }
-                       err = snd_input_stdio_open(&in, str, "r");
+
                        if (err < 0) {
                                SNDERR("Cannot access file %s", str);
                                free(str);
@@ -658,6 +810,7 @@ static int get_char_skip_comments(input_t *input)
                        fd->next = input->current;
                        fd->line = 1;
                        fd->column = 0;
+                       INIT_LIST_HEAD(&fd->include_paths);
                        input->current = fd;
                        continue;
                }
@@ -1668,6 +1821,7 @@ static int snd_config_load1(snd_config_t *config, snd_input_t *in, int override)
        fd->line = 1;
        fd->column = 0;
        fd->next = NULL;
+       INIT_LIST_HEAD(&fd->include_paths);
        input.current = fd;
        input.unget = 0;
        err = parse_defs(config, &input, 0, override);
@@ -1708,9 +1862,12 @@ static int snd_config_load1(snd_config_t *config, snd_input_t *in, int override)
                fd_next = fd->next;
                snd_input_close(fd->in);
                free(fd->name);
+               free_include_paths(fd);
                free(fd);
                fd = fd_next;
        }
+
+       free_include_paths(fd);
        free(fd);
        return err;
 }