From: Andre Noll <maan@tuebingen.mpg.de>
Date: Sun, 5 Sep 2021 20:38:41 +0000 (+0200)
Subject: Remove ->fd of struct audio file data.
X-Git-Tag: v0.6.4~6
X-Git-Url: http://git.tuebingen.mpg.de/?p=paraslash.git;a=commitdiff_plain;h=2176cbf10d8f3815f0a17bcc35e4d2e79440d26c

Remove ->fd of struct audio file data.

This structure contains information about the next audio file. It
is stored in a shared memory area, and a reference to this area is
sent through a pipe from the afs process to the server process. The
file descriptor of the next audio file, however, must be passed via
Unix socket magic (SCM_RIGHTS) and thus does not need to be part of
the structure.

Moreover, it's easier to define the afd structure in
open_and_update_audio_file() of aft.c rather than in its caller,
open_next_audio_file() of afs.c, because the caller only needs the
fd of the audio file and the shared memory ID but not the audio file
data structure itself.

Expand the documentation of open_and_update_audio_file() a bit while
at it.
---

diff --git a/afh.h b/afh.h
index 881db3c2..b3295f6e 100644
--- a/afh.h
+++ b/afh.h
@@ -58,8 +58,6 @@ struct afh_info {
 
 /** Data about the current audio file, passed from afs to server. */
 struct audio_file_data {
-	/** The open file descriptor to the current audio file. */
-	int fd;
 	/** Vss needs this for streaming. */
 	struct afh_info afhi;
 	/**
diff --git a/afs.c b/afs.c
index 050e1965..b6cce36f 100644
--- a/afs.c
+++ b/afs.c
@@ -418,11 +418,10 @@ static int pass_afd(int fd, char *buf, size_t size)
  */
 static int open_next_audio_file(void)
 {
-	struct audio_file_data afd;
-	int ret, shmid;
+	int ret, shmid, fd;
 	char buf[8];
 
-	ret = open_and_update_audio_file(&afd);
+	ret = open_and_update_audio_file(&fd);
 	if (ret < 0) {
 		if (ret != -OSL_ERRNO_TO_PARA_ERROR(E_OSL_RB_KEY_NOT_FOUND))
 			PARA_ERROR_LOG("%s\n", para_strerror(-ret));
@@ -435,8 +434,8 @@ static int open_next_audio_file(void)
 	}
 	*(uint32_t *)buf = NEXT_AUDIO_FILE;
 	*(uint32_t *)(buf + 4) = (uint32_t)shmid;
-	ret = pass_afd(afd.fd, buf, 8);
-	close(afd.fd);
+	ret = pass_afd(fd, buf, 8);
+	close(fd);
 	if (ret >= 0)
 		return ret;
 destroy:
diff --git a/afs.h b/afs.h
index cfa9cc6d..b1606493 100644
--- a/afs.h
+++ b/afs.h
@@ -255,7 +255,7 @@ int attribute_check_callback(struct afs_callback_arg *aca);
 void aft_init(struct afs_table *t);
 int aft_get_row_of_path(const char *path, struct osl_row **row);
 int aft_check_attributes(uint64_t att_mask, struct para_buffer *pb);
-int open_and_update_audio_file(struct audio_file_data *afd);
+int open_and_update_audio_file(int *fd);
 int load_afd(int shmid, struct audio_file_data *afd);
 int get_afsi_of_row(const struct osl_row *row, struct afs_info *afsi);
 int get_afhi_of_row(const struct osl_row *row, struct afh_info *afhi);
diff --git a/aft.c b/aft.c
index b358c96c..c8c98e7a 100644
--- a/aft.c
+++ b/aft.c
@@ -1024,7 +1024,14 @@ out:
 /**
  * Open the audio file with highest score and set up an afd structure.
  *
- * \param afd Result pointer.
+ * This determines and opens the next audio file, verifies that it did not
+ * change by comparing the recomputed the hash value of the file contents
+ * against the value stored in the audio file table. If all goes well, it
+ * creates a shared memory area containing the serialized version of the afd
+ * structure, including the chunk table, if any. The caller can then send the
+ * ID of this area and the open fd to the server process.
+ *
+ * \param fd Result pointer for the file descriptor of the audio file.
  *
  * On success, the numplayed field of the audio file selector info is increased
  * and the lastplayed time is set to the current time. Finally, the score of
@@ -1032,7 +1039,7 @@ out:
  *
  * \return Positive shmid on success, negative on errors.
  */
-int open_and_update_audio_file(struct audio_file_data *afd)
+int open_and_update_audio_file(int *fd)
 {
 	unsigned char file_hash[HASH_SIZE];
 	struct osl_object afsi_obj;
@@ -1042,6 +1049,7 @@ int open_and_update_audio_file(struct audio_file_data *afd)
 	struct osl_object map, chunk_table_obj;
 	struct ls_data *d = &status_item_ls_data;
 	unsigned char *tmp_hash;
+	struct audio_file_data afd;
 again:
 	ret = score_get_best(&current_aft_row, &d->score);
 	if (ret < 0)
@@ -1074,11 +1082,11 @@ again:
 	ret = load_afsi(&d->afsi, &afsi_obj);
 	if (ret < 0)
 		return ret;
-	ret = get_afhi_of_row(current_aft_row, &afd->afhi);
+	ret = get_afhi_of_row(current_aft_row, &afd.afhi);
 	if (ret < 0)
 		return ret;
-	d->afhi = afd->afhi;
-	d->afhi.chunk_table = afd->afhi.chunk_table = NULL;
+	d->afhi = afd.afhi;
+	d->afhi.chunk_table = afd.afhi.chunk_table = NULL;
 	ret = osl(osl_open_disk_object(audio_file_table, current_aft_row,
 		AFTCOL_CHUNKS, &chunk_table_obj));
 	if (ret < 0) {
@@ -1090,7 +1098,7 @@ again:
 	} else {
 		PARA_INFO_LOG("chunk table: %zu bytes\n", chunk_table_obj.size);
 	}
-	ret = mmap_full_file(d->path, O_RDONLY, &map.data, &map.size, &afd->fd);
+	ret = mmap_full_file(d->path, O_RDONLY, &map.data, &map.size, fd);
 	if (ret < 0)
 		goto out;
 	hash_function(map.data, map.size, file_hash);
@@ -1105,8 +1113,8 @@ again:
 	new_afsi.last_played = time(NULL);
 	save_afsi(&new_afsi, &afsi_obj); /* in-place update */
 
-	afd->audio_format_id = d->afsi.audio_format_id;
-	load_chunk_table(&afd->afhi, &chunk_table_obj);
+	afd.audio_format_id = d->afsi.audio_format_id;
+	load_chunk_table(&afd.afhi, &chunk_table_obj);
 	aced.aft_row = current_aft_row;
 	aced.old_afsi = &d->afsi;
 	/*
@@ -1116,9 +1124,9 @@ again:
 	ret = afs_event(AFSI_CHANGE, NULL, &aced);
 	if (ret < 0)
 		goto out;
-	ret = save_afd(afd);
+	ret = save_afd(&afd);
 out:
-	free(afd->afhi.chunk_table);
+	free(afd.afhi.chunk_table);
 	if (chunk_table_obj.data)
 		osl_close_disk_object(&chunk_table_obj);
 	if (ret < 0) {