From: Andre Noll <maan@systemlinux.org>
Date: Fri, 25 Nov 2011 12:13:35 +0000 (+0100)
Subject: Merge branch 't/generic_match_count'
X-Git-Tag: v0.4.9~3
X-Git-Url: http://git.tuebingen.mpg.de/?p=paraslash.git;a=commitdiff_plain;h=4867d9a4948aadde4dd59436e1c5fb0fc141ba89;hp=e65bdaa6b207d5cd409acaa5d0d33fe85dd7a28d

Merge branch 't/generic_match_count'
---

diff --git a/Makefile.in b/Makefile.in
index 68aa6bc9..23ceda47 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -66,7 +66,6 @@ CPPFLAGS += -I$(cmdline_dir)
 CPPFLAGS += @osl_cppflags@
 
 man_pages := $(patsubst %, man/man1/%.1, @executables@)
-man_pages_in := $(patsubst %, web/%.man.in.html, @executables@)
 
 ggo_dir := ggo
 object_dir := objects
@@ -120,8 +119,6 @@ tarball: $(tarball)
 	@[ -z "$(Q)" ] || echo 'GEN $@'
 	$(Q) ./command_util.sh man < $< > $@
 
-server_command_lists_ch = server_command_list.c afs_command_list.c \
-	server_command_list.h afs_command_list.h
 server_command_lists_man = server_command_list.man afs_command_list.man
 man/man1/para_server.1: para_server $(server_command_lists_man) | $(man_dir)
 	@[ -z "$(Q)" ] || echo 'MAN $<'
@@ -255,7 +252,7 @@ para_gui: $(gui_objs)
 	@[ -z "$(Q)" ] || echo 'LD $@'
 	$(Q) $(CC) $(LDFLAGS) -o $@ $(gui_objs) -lcurses
 
-para_audiod: audiod_command_list.c audiod_command_list.h $(audiod_objs)
+para_audiod: $(audiod_objs)
 	@[ -z "$(Q)" ] || echo 'LD $@'
 	$(Q) $(CC) $(LDFLAGS) -o $@ $(audiod_objs) @audiod_ldflags@
 
@@ -267,7 +264,7 @@ para_fade: $(fade_objs)
 	@[ -z "$(Q)" ] || echo 'LD $@'
 	$(Q) $(CC) $(LDFLAGS) -o $@ $(fade_objs) @fade_ldflags@
 
-para_server: $(server_command_lists_ch) $(server_objs)
+para_server: $(server_objs)
 	@[ -z "$(Q)" ] || echo 'LD $@'
 	$(Q) $(CC) $(LDFLAGS) -o $@ $(server_objs)  @server_ldflags@
 
diff --git a/NEWS b/NEWS
index a79cc29f..0b8b33e8 100644
--- a/NEWS
+++ b/NEWS
@@ -15,6 +15,11 @@
 	  communication between para_server and para_audiod.
 	- The alsa writer eats up less CPU cycles when configured to
 	  use the DMIX plugin.
+	- Simplified and unified receiver code.
+	- Makefile cleanups.
+	- Commands which print a list of matching audio files now
+	  emit a meaningful error message if no audio file matched the
+	  given pattern(s).
 
 --------------------------------------
 0.4.8 (2011-08-19) "nested assignment"
diff --git a/audiod.c b/audiod.c
index 4864c855..8008e2cb 100644
--- a/audiod.c
+++ b/audiod.c
@@ -1381,7 +1381,7 @@ int main(int argc, char *argv[])
 	init_command_task(cmd_task);
 
 	if (conf.daemon_given)
-		daemonize();
+		daemonize(false /* parent exits immediately */);
 
 	register_task(&sig_task->task);
 	register_task(&cmd_task->task);
diff --git a/daemon.c b/daemon.c
index ffdec4e3..0bf2f0ac 100644
--- a/daemon.c
+++ b/daemon.c
@@ -12,6 +12,7 @@
 #include <grp.h>
 #include <sys/time.h>
 #include <stdbool.h>
+#include <signal.h>
 
 #include "para.h"
 #include "daemon.h"
@@ -142,14 +143,25 @@ static bool daemon_test_flag(unsigned flag)
 	return me->flags & flag;
 }
 
+static void dummy_sighandler(__a_unused int s)
+{
+}
+
 /**
  * Do the usual stuff to become a daemon.
  *
- * Fork, become session leader, dup fd 0, 1, 2 to /dev/null.
+ * \param parent_waits Whether the parent process should pause before exit.
  *
- * \sa fork(2), setsid(2), dup(2).
+ * Fork, become session leader, cd to /, and dup fd 0, 1, 2 to /dev/null. If \a
+ * parent_waits is false, the parent process terminates immediately.
+ * Otherwise, it calls pause() to sleep until it receives \p SIGTERM or \p
+ * SIGCHLD and exits successfully thereafter. This behaviour is useful if the
+ * daemon process should not detach from the console until the child process
+ * has completed its setup.
+ *
+ * \sa fork(2), setsid(2), dup(2), pause(2).
  */
-void daemonize(void)
+void daemonize(bool parent_waits)
 {
 	pid_t pid;
 	int null;
@@ -158,8 +170,14 @@ void daemonize(void)
 	pid = fork();
 	if (pid < 0)
 		goto err;
-	if (pid)
+	if (pid) {
+		if (parent_waits) {
+			signal(SIGTERM, dummy_sighandler);
+			signal(SIGCHLD, dummy_sighandler);
+			pause();
+		}
 		exit(EXIT_SUCCESS); /* parent exits */
+	}
 	/* become session leader */
 	if (setsid() < 0)
 		goto err;
diff --git a/daemon.h b/daemon.h
index d5583f58..3fe72ea9 100644
--- a/daemon.h
+++ b/daemon.h
@@ -1,7 +1,7 @@
 /** \file daemon.h exported symbols from daemon.c */
 
 
-void daemonize(void);
+void daemonize(bool parent_waits);
 void daemon_open_log_or_die(void);
 void daemon_close_log(void);
 void log_welcome(const char *whoami);
diff --git a/dccp_recv.c b/dccp_recv.c
index a9eab006..41518539 100644
--- a/dccp_recv.c
+++ b/dccp_recv.c
@@ -27,33 +27,15 @@
 
 #include "dccp_recv.cmdline.h"
 
-/**
- * data specific to the dccp receiver
- *
- * \sa receiver receiver_node
- */
-struct private_dccp_recv_data {
-	/** the file descriptor for the dccp socket */
-	int fd;
-	struct btr_pool *btrp;
-};
-
 static void dccp_recv_close(struct receiver_node *rn)
 {
-	struct private_dccp_recv_data *pdd = rn->private_data;
-
-	if (!pdd)
-		return;
-	if (pdd->fd > 0)
-		close(pdd->fd);
-	btr_pool_free(pdd->btrp);
-	free(pdd);
-	rn->private_data = NULL;
+	if (rn->fd > 0)
+		close(rn->fd);
+	btr_pool_free(rn->btrp);
 }
 
 static int dccp_recv_open(struct receiver_node *rn)
 {
-	struct private_dccp_recv_data *pdd;
 	struct dccp_recv_args_info *conf = rn->conf;
 	struct flowopts *fo = NULL;
 	uint8_t *ccids = NULL;
@@ -87,9 +69,8 @@ static int dccp_recv_open(struct receiver_node *rn)
 	ret = mark_fd_nonblocking(fd);
 	if (ret < 0)
 		goto err;
-	rn->private_data = pdd = para_calloc(sizeof(struct private_dccp_recv_data));
-	pdd->btrp = btr_pool_new("dccp_recv", 320 * 1024);
-	pdd->fd = fd;
+	rn->btrp = btr_pool_new("dccp_recv", 320 * 1024);
+	rn->fd = fd;
 	return 1;
 err:
 	close(fd);
@@ -136,18 +117,16 @@ static void *dccp_recv_parse_config(int argc, char **argv)
 static void dccp_recv_pre_select(struct sched *s, struct task *t)
 {
 	struct receiver_node *rn = container_of(t, struct receiver_node, task);
-	struct private_dccp_recv_data *pdd = rn->private_data;
 
 	t->error = 0;
 	if (generic_recv_pre_select(s, t) <= 0)
 		return;
-	para_fd_set(pdd->fd, &s->rfds, &s->max_fileno);
+	para_fd_set(rn->fd, &s->rfds, &s->max_fileno);
 }
 
 static void dccp_recv_post_select(struct sched *s, struct task *t)
 {
 	struct receiver_node *rn = container_of(t, struct receiver_node, task);
-	struct private_dccp_recv_data *pdd = rn->private_data;
 	struct btr_node *btrn = rn->btrn;
 	struct iovec iov[2];
 	int ret, iovcnt;
@@ -156,18 +135,18 @@ static void dccp_recv_post_select(struct sched *s, struct task *t)
 	ret = btr_node_status(btrn, 0, BTR_NT_ROOT);
 	if (ret <= 0)
 		goto out;
-	iovcnt = btr_pool_get_buffers(pdd->btrp, iov);
+	iovcnt = btr_pool_get_buffers(rn->btrp, iov);
 	ret = -E_DCCP_OVERRUN;
 	if (iovcnt == 0)
 		goto out;
-	ret = readv_nonblock(pdd->fd, iov, iovcnt, &s->rfds, &num_bytes);
+	ret = readv_nonblock(rn->fd, iov, iovcnt, &s->rfds, &num_bytes);
 	if (num_bytes == 0)
 		goto out;
 	if (num_bytes <= iov[0].iov_len) /* only the first buffer was filled */
-		btr_add_output_pool(pdd->btrp, num_bytes, btrn);
+		btr_add_output_pool(rn->btrp, num_bytes, btrn);
 	else { /* both buffers contain data */
-		btr_add_output_pool(pdd->btrp, iov[0].iov_len, btrn);
-		btr_add_output_pool(pdd->btrp, num_bytes - iov[0].iov_len, btrn);
+		btr_add_output_pool(rn->btrp, iov[0].iov_len, btrn);
+		btr_add_output_pool(rn->btrp, num_bytes - iov[0].iov_len, btrn);
 	}
 out:
 	if (ret >= 0)
diff --git a/http_recv.c b/http_recv.c
index 5717692c..e6031e75 100644
--- a/http_recv.c
+++ b/http_recv.c
@@ -44,24 +44,6 @@ struct private_http_recv_data {
 	 * \sa receiver::open, receiver_node.
 	 */
 	enum http_recv_status status;
-	/**
-	 * The file descriptor used for receiving the http stream.
-	 *
-	 * The pre_select function of the http receiver adds this file descriptor to
-	 * the set of file descriptors which are checked for reading/writing (depending
-	 * on the current status) by the select loop of the application (para_audiod or
-	 * para_recv).
-	 *
-	 * The post_select function of the http receiver uses \a fd, if ready, to
-	 * establish the http connection, and updates \a status according to the new
-	 * state of the connection.  As soon as \a status is \p HTTP_STREAMING, \a fd is
-	 * going to be only checked for reading. If data is available, it is read into
-	 * the output buffer of the receiver node by post_select.
-	 *
-	 * \sa receiver::pre_select receiver::post_select receiver_node, http_recv_status
-	 */
-	int fd;
-	struct btr_pool *btrp;
 };
 
 static char *make_request_msg(void)
@@ -82,43 +64,48 @@ static void http_recv_pre_select(struct sched *s, struct task *t)
 	if (generic_recv_pre_select(s, t) <= 0)
 		return;
 	if  (phd->status == HTTP_CONNECTED)
-		para_fd_set(phd->fd, &s->wfds, &s->max_fileno);
+		para_fd_set(rn->fd, &s->wfds, &s->max_fileno);
 	else
-		para_fd_set(phd->fd, &s->rfds, &s->max_fileno);
+		para_fd_set(rn->fd, &s->rfds, &s->max_fileno);
 }
 
+/*
+ * Establish the http connection. If already established, fill the buffer pool
+ * area with data read from the socket. In any case, update the state of the
+ * connection if necessary.
+ */
 static void http_recv_post_select(struct sched *s, struct task *t)
 {
 	struct receiver_node *rn = container_of(t, struct receiver_node, task);
 	struct private_http_recv_data *phd = rn->private_data;
 	struct btr_node *btrn = rn->btrn;
-	int ret;
-	char *buf;
-	size_t sz, n;
+	int ret, iovcnt;
+	struct iovec iov[2];
+	size_t num_bytes;
 
 	t->error = 0;
 	ret = btr_node_status(btrn, 0, BTR_NT_ROOT);
 	if (ret < 0)
-		goto err;
+		goto out;
 	if (ret == 0)
 		return;
 	if (phd->status == HTTP_CONNECTED) {
 		char *rq;
-		if (!FD_ISSET(phd->fd, &s->wfds))
+		if (!FD_ISSET(rn->fd, &s->wfds))
 			return;
 		rq = make_request_msg();
 		PARA_INFO_LOG("sending http request\n");
-		ret = send_va_buffer(phd->fd, "%s", rq);
+		ret = send_va_buffer(rn->fd, "%s", rq);
 		free(rq);
 		if (ret < 0)
-			goto err;
+			goto out;
 		phd->status = HTTP_SENT_GET_REQUEST;
 		return;
 	}
 	if (phd->status == HTTP_SENT_GET_REQUEST) {
-		ret = read_pattern(phd->fd, HTTP_OK_MSG, strlen(HTTP_OK_MSG), &s->rfds);
+		ret = read_pattern(rn->fd, HTTP_OK_MSG, strlen(HTTP_OK_MSG), &s->rfds);
 		if (ret < 0)
-			goto err;
+			goto out;
 		if (ret == 0)
 			return;
 		PARA_INFO_LOG("received ok msg, streaming\n");
@@ -126,25 +113,29 @@ static void http_recv_post_select(struct sched *s, struct task *t)
 		return;
 	}
 	ret = -E_HTTP_RECV_OVERRUN;
-	sz = btr_pool_get_buffer(phd->btrp, &buf);
-	if (sz == 0)
-		goto err;
-	ret = read_nonblock(phd->fd, buf, sz, &s->rfds, &n);
-	if (n > 0)
-		btr_add_output_pool(phd->btrp, n, btrn);
+	iovcnt = btr_pool_get_buffers(rn->btrp, iov);
+	if (iovcnt == 0)
+		goto out;
+	ret = readv_nonblock(rn->fd, iov, iovcnt, &s->rfds, &num_bytes);
+	if (num_bytes == 0)
+		goto out;
+	if (num_bytes <= iov[0].iov_len) /* only the first buffer was filled */
+		btr_add_output_pool(rn->btrp, num_bytes, btrn);
+	else { /* both buffers contain data */
+		btr_add_output_pool(rn->btrp, iov[0].iov_len, btrn);
+		btr_add_output_pool(rn->btrp, num_bytes - iov[0].iov_len, btrn);
+	}
+out:
 	if (ret >= 0)
 		return;
-err:
 	btr_remove_node(rn->btrn);
 	t->error = ret;
 }
 
 static void http_recv_close(struct receiver_node *rn)
 {
-	struct private_http_recv_data *phd = rn->private_data;
-
-	close(phd->fd);
-	btr_pool_free(phd->btrp);
+	close(rn->fd);
+	btr_pool_free(rn->btrp);
 	free(rn->private_data);
 }
 
@@ -174,9 +165,9 @@ static int http_recv_open(struct receiver_node *rn)
 		return ret;
 	}
 	rn->private_data = phd = para_calloc(sizeof(struct private_http_recv_data));
-	phd->fd = fd;
+	rn->fd = fd;
 	phd->status = HTTP_CONNECTED;
-	phd->btrp = btr_pool_new("http_recv", 320 * 1024);
+	rn->btrp = btr_pool_new("http_recv", 320 * 1024);
 	return 1;
 }
 
diff --git a/recv.h b/recv.h
index 7555dfb4..92b63d27 100644
--- a/recv.h
+++ b/recv.h
@@ -20,6 +20,21 @@ struct receiver_node {
 	struct task task;
 	/** The receiver node is always the root of the buffer tree. */
 	struct btr_node *btrn;
+	/** Each receiver node maintains a buffer pool for the received data. */
+	struct btr_pool *btrp;
+	/**
+	 * The file descriptor to receive the stream.
+	 *
+	 * The pre_select function of the receiver adds this file descriptor to
+	 * the set of file descriptors which are watched for readability or
+	 * writability, depending on the state of the connection (if any).
+	 *
+	 * If \a fd is readable, the post_select function of the receiver reads
+	 * data from this fd into the buffer pool area of \a btrp.
+	 *
+	 * \sa \ref receiver.
+	 */
+	int fd;
 };
 
 /**
diff --git a/server.c b/server.c
index 0cfac607..7f020c8f 100644
--- a/server.c
+++ b/server.c
@@ -491,10 +491,9 @@ static void server_init(int argc, char **argv)
 	gettimeofday(now, NULL);
 	set_server_start_time(now);
 	init_user_list(user_list_file);
-	init_server_command_task(argc, argv);
 	/* become daemon */
 	if (conf.daemon_given)
-		daemonize();
+		daemonize(true /* parent waits for SIGTERM */);
 	PARA_NOTICE_LOG("initializing audio format handlers\n");
 	afh_init();
 
@@ -519,6 +518,9 @@ static void server_init(int argc, char **argv)
 	para_unblock_signal(SIGCHLD);
 	PARA_NOTICE_LOG("initializing virtual streaming system\n");
 	init_vss_task(afs_socket);
+	init_server_command_task(argc, argv);
+	if (conf.daemon_given)
+		kill(getppid(), SIGTERM);
 	PARA_NOTICE_LOG("server init complete\n");
 }
 
diff --git a/udp_recv.c b/udp_recv.c
index 45d24eae..964b60d4 100644
--- a/udp_recv.c
+++ b/udp_recv.c
@@ -22,25 +22,13 @@
 #include "fd.h"
 #include "buffer_tree.h"
 
-/**
- * Data specific to the udp receiver.
- *
- * \sa \ref receiver, \ref receiver_node.
- */
-struct private_udp_recv_data {
-	/** The socket file descriptor. */
-	int fd;
-	struct btr_pool *btrp;
-};
-
 static void udp_recv_pre_select(struct sched *s, struct task *t)
 {
 	struct receiver_node *rn = container_of(t, struct receiver_node, task);
-	struct private_udp_recv_data *purd = rn->private_data;
 
 	if (generic_recv_pre_select(s, t) <= 0)
 		return;
-	para_fd_set(purd->fd, &s->rfds, &s->max_fileno);
+	para_fd_set(rn->fd, &s->rfds, &s->max_fileno);
 }
 
 static int udp_check_eof(size_t sz, struct iovec iov[2])
@@ -64,7 +52,6 @@ static int udp_check_eof(size_t sz, struct iovec iov[2])
 static void udp_recv_post_select(__a_unused struct sched *s, struct task *t)
 {
 	struct receiver_node *rn = container_of(t, struct receiver_node, task);
-	struct private_udp_recv_data *purd = rn->private_data;
 	struct btr_node *btrn = rn->btrn;
 	size_t num_bytes;
 	struct iovec iov[2];
@@ -74,11 +61,11 @@ static void udp_recv_post_select(__a_unused struct sched *s, struct task *t)
 	ret = btr_node_status(btrn, 0, BTR_NT_ROOT);
 	if (ret <= 0)
 		goto out;
-	iovcnt = btr_pool_get_buffers(purd->btrp, iov);
+	iovcnt = btr_pool_get_buffers(rn->btrp, iov);
 	ret = -E_UDP_OVERRUN;
 	if (iovcnt == 0)
 		goto out;
-	ret = readv_nonblock(purd->fd, iov, iovcnt, &s->rfds, &num_bytes);
+	ret = readv_nonblock(rn->fd, iov, iovcnt, &s->rfds, &num_bytes);
 	if (num_bytes == 0)
 		goto out;
 	readv_ret = ret;
@@ -86,10 +73,10 @@ static void udp_recv_post_select(__a_unused struct sched *s, struct task *t)
 	if (ret < 0)
 		goto out;
 	if (iov[0].iov_len >= num_bytes)
-		btr_add_output_pool(purd->btrp, num_bytes, btrn);
+		btr_add_output_pool(rn->btrp, num_bytes, btrn);
 	else { /* both buffers contain data */
-		btr_add_output_pool(purd->btrp, iov[0].iov_len, btrn);
-		btr_add_output_pool(purd->btrp, num_bytes - iov[0].iov_len,
+		btr_add_output_pool(rn->btrp, iov[0].iov_len, btrn);
+		btr_add_output_pool(rn->btrp, num_bytes - iov[0].iov_len,
 			btrn);
 	}
 	ret = readv_ret;
@@ -98,18 +85,15 @@ out:
 		return;
 	btr_remove_node(btrn);
 	t->error = ret;
-	close(purd->fd);
-	purd->fd = -1;
+	close(rn->fd);
+	rn->fd = -1;
 }
 
 static void udp_recv_close(struct receiver_node *rn)
 {
-	struct private_udp_recv_data *purd = rn->private_data;
-
-	if (purd->fd >= 0)
-		close(purd->fd);
-	btr_pool_free(purd->btrp);
-	free(rn->private_data);
+	if (rn->fd >= 0)
+		close(rn->fd);
+	btr_pool_free(rn->btrp);
 }
 
 static void *udp_recv_parse_config(int argc, char **argv)
@@ -188,36 +172,31 @@ err:
 
 static int udp_recv_open(struct receiver_node *rn)
 {
-	struct private_udp_recv_data *purd;
 	struct udp_recv_args_info *c = rn->conf;
 	char  *iface = c->iface_given ? c->iface_arg : NULL;
 	int ret;
 
-	rn->private_data = para_calloc(sizeof(struct private_udp_recv_data));
-	purd = rn->private_data;
-
 	ret = makesock(IPPROTO_UDP, 1, c->host_arg, c->port_arg, NULL);
 	if (ret < 0)
 		goto err;
-	purd->fd = ret;
+	rn->fd = ret;
 
-	ret = mcast_receiver_setup(purd->fd, iface);
+	ret = mcast_receiver_setup(rn->fd, iface);
 	if (ret < 0) {
-		close(purd->fd);
+		close(rn->fd);
 		goto err;
 	}
 
-	ret = mark_fd_nonblocking(purd->fd);
+	ret = mark_fd_nonblocking(rn->fd);
 	if (ret < 0) {
-		close(purd->fd);
+		close(rn->fd);
 		goto err;
 	}
 	PARA_INFO_LOG("receiving from %s:%d, fd=%d\n", c->host_arg,
-		c->port_arg, purd->fd);
-	purd->btrp = btr_pool_new("udp_recv", 320 * 1024);
-	return purd->fd;
+		c->port_arg, rn->fd);
+	rn->btrp = btr_pool_new("udp_recv", 320 * 1024);
+	return rn->fd;
 err:
-	free(rn->private_data);
 	return ret;
 }
 
diff --git a/vss.c b/vss.c
index e336a9e7..4a8aafa8 100644
--- a/vss.c
+++ b/vss.c
@@ -361,8 +361,17 @@ static void vss_get_chunk(int chunk_num, struct vss_task *vsst,
 static void compute_group_size(struct vss_task *vsst, struct fec_group *g,
 		int max_bytes)
 {
+	char *buf;
+	size_t len;
 	int i, max_chunks = PARA_MAX(1LU, 150 / tv2ms(vss_chunk_time()));
 
+	if (g->first_chunk == 0) {
+		g->num_chunks = 1;
+		vss_get_chunk(0, vsst, &buf, &len);
+		g->bytes = len;
+		return;
+	}
+
 	g->num_chunks = 0;
 	g->bytes = 0;
 	/*
@@ -372,8 +381,6 @@ static void compute_group_size(struct vss_task *vsst, struct fec_group *g,
 	 * of exactly one chunk for these audio formats.
 	 */
 	for (i = 0;; i++) {
-		char *buf;
-		size_t len;
 		int chunk_num = g->first_chunk + i;
 
 		if (g->bytes > 0 && i >= max_chunks) /* duration limit */
@@ -502,7 +509,7 @@ static int setup_next_fec_group(struct fec_client *fc, struct vss_task *vsst)
 {
 	int ret, i, k, n, data_slices;
 	size_t len;
-	char *buf;
+	char *buf, *p;
 	struct fec_group *g = &fc->group;
 
 	if (fc->state == FEC_STATE_NONE) {
@@ -562,16 +569,20 @@ static int setup_next_fec_group(struct fec_client *fc, struct vss_task *vsst)
 		assert(i == g->num_header_slices - 1);
 	}
 
-	/* setup data slices */
+	/*
+	 * Setup data slices. Note that for ogg streams chunk 0 points to a
+	 * buffer on the heap rather than to the mapped audio file.
+	 */
 	vss_get_chunk(g->first_chunk, vsst, &buf, &len);
-	for (; i < g->num_header_slices + data_slices; i++) {
-		if (buf + g->slice_bytes > vsst->map + mmd->size) {
+	for (p = buf; i < g->num_header_slices + data_slices; i++) {
+		if (p + g->slice_bytes > buf + g->bytes) {
 			/*
-			 * Can not use the memory mapped audio file for this
-			 * slice as it goes beyond the map.
+			 * We must make a copy for this slice since using p
+			 * directly would exceed the buffer.
 			 */
-			uint32_t payload_size = vsst->map + mmd->size - buf;
-			memcpy(fc->extra_src_buf, buf, payload_size);
+			uint32_t payload_size = buf + g->bytes - p;
+			assert(payload_size + FEC_HEADER_SIZE <= fc->mps);
+			memcpy(fc->extra_src_buf, p, payload_size);
 			if (payload_size < g->slice_bytes)
 				memset(fc->extra_src_buf + payload_size, 0,
 					g->slice_bytes - payload_size);
@@ -579,8 +590,8 @@ static int setup_next_fec_group(struct fec_client *fc, struct vss_task *vsst)
 			i++;
 			break;
 		}
-		fc->src_data[i] = (const unsigned char *)buf;
-		buf += g->slice_bytes;
+		fc->src_data[i] = (const unsigned char *)p;
+		p += g->slice_bytes;
 	}
 	if (i < k) {
 		/* use arbitrary data for all remaining slices */
@@ -1079,8 +1090,6 @@ static void vss_send(struct vss_task *vsst)
 			senders[i].send(mmd->current_chunk, mmd->chunks_sent,
 				buf, len, vsst->header_buf, vsst->header_len);
 		}
-		mmd->chunks_sent++;
-		mmd->current_chunk++;
 		/*
 		 * Prefault next chunk(s)
 		 *
@@ -1093,11 +1102,15 @@ static void vss_send(struct vss_task *vsst)
 		 * eliminate the delays completely. Moreover, it is supported
 		 * only on Linux. So we do our own read-ahead here.
 		 */
-		buf += len;
-		for (i = 0; i < 5 && buf < vsst->map + mmd->size; i++) {
-			__a_unused volatile char x = *buf;
-			buf += 4096;
+		if (mmd->current_chunk > 0) { /* chunk 0 might be on the heap */
+			buf += len;
+			for (i = 0; i < 5 && buf < vsst->map + mmd->size; i++) {
+				__a_unused volatile char x = *buf;
+				buf += 4096;
+			}
 		}
+		mmd->chunks_sent++;
+		mmd->current_chunk++;
 	}
 }