[alsa-devel] [RFCv2][PATCH 02/38] axfer: add a sub-command to print list of PCMs/devices
Takashi Sakamoto
o-takashi at sakamocchi.jp
Tue Sep 19 02:43:42 CEST 2017
Original aplay implementation has a feature to output two types of list;
devices and PCMs. The list of devices is a result to query sound card and
pcm component structured maintained in kernel land. The list of PCMs is a
result to parse runtime configuration files in alsa-lib. Entries in the
former list is corresponding to ALSA PCM character device
('/dev/snd/pcm%uC%uD[p|c]'), while entries in the latter list includes
some 'virtual' instances in application runtime.
This commit adds an implementation for the above functionality. This is
executed by taking 'list' sub-command. A 'device' option has the same
effect as '--list-devices' and '-L' of aplay. A 'pcm' option has the same
effect as '--list-pcms' and '-l' of aplay. In both cases, an additional
option is required for stream direction. Below is examples of new command
system for this sub-command.
$ axfer list device -C (= arecord --list-devices)
$ axfer list pcm -P (= aplay -l)
Signed-off-by: Takashi Sakamoto <o-takashi at sakamocchi.jp>
---
axfer/Makefile.am | 3 +-
axfer/main.c | 2 +-
axfer/subcmd-list.c | 234 ++++++++++++++++++++++++++++++++++++++++++++++++++++
axfer/subcmd.h | 2 +
4 files changed, 239 insertions(+), 2 deletions(-)
create mode 100644 axfer/subcmd-list.c
diff --git a/axfer/Makefile.am b/axfer/Makefile.am
index b48b9c57..4e37b92f 100644
--- a/axfer/Makefile.am
+++ b/axfer/Makefile.am
@@ -20,4 +20,5 @@ noinst_HEADERS = \
axfer_SOURCES = \
misc.h \
subcmd.h \
- main.c
+ main.c \
+ subcmd-list.c
diff --git a/axfer/main.c b/axfer/main.c
index 6ea10842..9bf02fd9 100644
--- a/axfer/main.c
+++ b/axfer/main.c
@@ -182,7 +182,7 @@ int main(int argc, char *const *argv)
if (subcmd == SUBCMD_TRANSFER)
printf("execute 'transfer' subcmd.\n");
else if (subcmd == SUBCMD_LIST)
- printf("execute 'list' subcmd.\n");
+ err = subcmd_list(argc, argv, direction);
else if (subcmd == SUBCMD_VERSION)
print_version(argv[0]);
else
diff --git a/axfer/subcmd-list.c b/axfer/subcmd-list.c
new file mode 100644
index 00000000..de4bbd76
--- /dev/null
+++ b/axfer/subcmd-list.c
@@ -0,0 +1,234 @@
+/*
+ * subcmd-list.c - operations for list sub command.
+ *
+ * Copyright (c) 2017 Takashi Sakamoto <o-takashi at sakamocchi.jp>
+ *
+ * Licensed under the terms of the GNU General Public License, version 2.
+ */
+
+#include "subcmd.h"
+#include "misc.h"
+
+#include <getopt.h>
+
+static int dump_device(snd_ctl_t *handle, const char *id, const char *name,
+ snd_pcm_stream_t direction, snd_pcm_info_t *info)
+{
+ unsigned int count;
+ int i;
+ int err;
+
+ printf(_("card %i: %s [%s], device %i: %s [%s]\n"),
+ snd_pcm_info_get_card(info), id, name,
+ snd_pcm_info_get_device(info), snd_pcm_info_get_id(info),
+ snd_pcm_info_get_name(info));
+
+ count = snd_pcm_info_get_subdevices_count(info);
+ printf(_(" Subdevices: %i/%i\n"),
+ snd_pcm_info_get_subdevices_avail(info), count);
+
+ for (i = 0; i < count; ++i) {
+ snd_pcm_info_set_subdevice(info, i);
+
+ err = snd_ctl_pcm_info(handle, info);
+ if (err < 0) {
+ printf("control digital audio playback info (%i): %s",
+ snd_pcm_info_get_card(info), snd_strerror(err));
+ continue;
+ }
+
+ printf(_(" Subdevice #%i: %s\n"),
+ i, snd_pcm_info_get_subdevice_name(info));
+ }
+
+ return 0;
+}
+
+static int dump_devices(snd_ctl_t *handle, const char *id, const char *name,
+ snd_pcm_stream_t direction)
+{
+ snd_pcm_info_t *info;
+ int device = -1;
+ int err;
+
+ err = snd_pcm_info_malloc(&info);
+ if (err < 0)
+ return err;
+
+ while (1) {
+ err = snd_ctl_pcm_next_device(handle, &device);
+ if (err < 0)
+ break;
+ if (device < 0)
+ break;
+
+ snd_pcm_info_set_device(info, device);
+ snd_pcm_info_set_subdevice(info, 0);
+ snd_pcm_info_set_stream(info, direction);
+ err = snd_ctl_pcm_info(handle, info);
+ if (err < 0)
+ continue;
+
+ err = dump_device(handle, id, name, direction, info);
+ if (err < 0)
+ break;
+ }
+
+ free(info);
+ return err;
+}
+
+static int list_devices(snd_pcm_stream_t direction)
+{
+ int card = -1;
+ char name[32];
+ snd_ctl_t *handle;
+ snd_ctl_card_info_t *info;
+ int err;
+
+ err = snd_ctl_card_info_malloc(&info);
+ if (err < 0)
+ return err;
+
+ /* Not found. */
+ if (snd_card_next(&card) < 0 || card < 0)
+ goto end;
+
+ printf(_("**** List of %s Hardware Devices ****\n"),
+ snd_pcm_stream_name(direction));
+
+ while (card >= 0) {
+ sprintf(name, "hw:%d", card);
+ err = snd_ctl_open(&handle, name, 0);
+ if (err < 0) {
+ printf("control open (%i): %s",
+ card, snd_strerror(err));
+ } else {
+ err = snd_ctl_card_info(handle, info);
+ if (err < 0) {
+ printf("control hardware info (%i): %s",
+ card, snd_strerror(err));
+ } else {
+ err = dump_devices(handle,
+ snd_ctl_card_info_get_id(info),
+ snd_ctl_card_info_get_name(info),
+ direction);
+ }
+ snd_ctl_close(handle);
+ }
+
+ if (err < 0)
+ break;
+
+ /* Go to next. */
+ if (snd_card_next(&card) < 0) {
+ printf("snd_card_next");
+ break;
+ }
+ }
+end:
+ free(info);
+ return err;
+}
+
+static int list_pcms(snd_pcm_stream_t direction)
+{
+ static const char *const filters[] = {
+ [SND_PCM_STREAM_CAPTURE] = "Input",
+ [SND_PCM_STREAM_PLAYBACK] = "Output",
+ };
+ const char *filter;
+ void **hints;
+ void **n;
+ char *io;
+ char *name;
+ char *desc;
+
+ if (snd_device_name_hint(-1, "pcm", &hints) < 0)
+ return -EINVAL;
+
+ filter = filters[direction];
+
+ n = hints;
+ for (n = hints; *n != NULL; ++n) {
+ io = snd_device_name_get_hint(*n, "IOID");
+ if (io != NULL && strcmp(io, filter) != 0) {
+ free(io);
+ continue;
+ }
+
+ name = snd_device_name_get_hint(*n, "NAME");
+ desc = snd_device_name_get_hint(*n, "DESC");
+
+ printf("%s\n", name);
+ if (desc == NULL) {
+ free(name);
+ free(desc);
+ continue;
+ }
+
+
+ printf(" ");
+ while (*desc) {
+ if (*desc == '\n')
+ printf("\n ");
+ else
+ putchar(*desc);
+ desc++;
+ }
+ putchar('\n');
+ }
+
+ snd_device_name_free_hint(hints);
+
+ return 0;
+}
+
+static void print_help(void)
+{
+ printf("help for list sub-command.\n");
+}
+
+int subcmd_list(int argc, char *const *argv, snd_pcm_stream_t direction)
+{
+ static const struct {
+ const char *const category;
+ int (*func)(snd_pcm_stream_t direction);
+ } ops[] = {
+ {"device", list_devices},
+ {"pcm", list_pcms},
+ };
+ int i;
+ static const char *s_opts = "hlL";
+ static const struct option l_opts[] = {
+ {"list-devices", 0, NULL, 'l'},
+ {"list-pcms", 0, NULL, 'L'},
+ {NULL, 0, NULL, 0}
+ };
+ int c;
+
+ /* Renewed command system. */
+ if (argc > 2 && !strcmp(argv[1], "list")) {
+ for (i = 0; i < ARRAY_SIZE(ops); ++i) {
+ if (!strcmp(ops[i].category, argv[2]))
+ return ops[i].func(direction);
+ }
+ }
+
+ /* Original command system. */
+ optind = 0;
+ opterr = 0;
+ while (1) {
+ c = getopt_long(argc, argv, s_opts, l_opts, NULL);
+ if (c < 0)
+ break;
+ if (c == 'l')
+ return list_devices(direction);
+ if (c == 'L')
+ return list_pcms(direction);
+ }
+
+ print_help();
+
+ return 1;
+}
diff --git a/axfer/subcmd.h b/axfer/subcmd.h
index 7b52ddc7..940d6814 100644
--- a/axfer/subcmd.h
+++ b/axfer/subcmd.h
@@ -11,4 +11,6 @@
#include <alsa/asoundlib.h>
+int subcmd_list(int argc, char *const *argv, snd_pcm_stream_t direction);
+
#endif
--
2.11.0
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