Root/sound/core/info.c

1/*
2 * Information interface for ALSA driver
3 * Copyright (c) by Jaroslav Kysela <perex@perex.cz>
4 *
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
19 *
20 */
21
22#include <linux/init.h>
23#include <linux/time.h>
24#include <linux/mm.h>
25#include <linux/slab.h>
26#include <linux/string.h>
27#include <sound/core.h>
28#include <sound/minors.h>
29#include <sound/info.h>
30#include <sound/version.h>
31#include <linux/proc_fs.h>
32#include <linux/mutex.h>
33#include <stdarg.h>
34
35/*
36 *
37 */
38
39#ifdef CONFIG_PROC_FS
40
41int snd_info_check_reserved_words(const char *str)
42{
43    static char *reserved[] =
44    {
45        "version",
46        "meminfo",
47        "memdebug",
48        "detect",
49        "devices",
50        "oss",
51        "cards",
52        "timers",
53        "synth",
54        "pcm",
55        "seq",
56        NULL
57    };
58    char **xstr = reserved;
59
60    while (*xstr) {
61        if (!strcmp(*xstr, str))
62            return 0;
63        xstr++;
64    }
65    if (!strncmp(str, "card", 4))
66        return 0;
67    return 1;
68}
69
70static DEFINE_MUTEX(info_mutex);
71
72struct snd_info_private_data {
73    struct snd_info_buffer *rbuffer;
74    struct snd_info_buffer *wbuffer;
75    struct snd_info_entry *entry;
76    void *file_private_data;
77};
78
79static int snd_info_version_init(void);
80static int snd_info_version_done(void);
81static void snd_info_disconnect(struct snd_info_entry *entry);
82
83
84/* resize the proc r/w buffer */
85static int resize_info_buffer(struct snd_info_buffer *buffer,
86                  unsigned int nsize)
87{
88    char *nbuf;
89
90    nsize = PAGE_ALIGN(nsize);
91    nbuf = krealloc(buffer->buffer, nsize, GFP_KERNEL);
92    if (! nbuf)
93        return -ENOMEM;
94
95    buffer->buffer = nbuf;
96    buffer->len = nsize;
97    return 0;
98}
99
100/**
101 * snd_iprintf - printf on the procfs buffer
102 * @buffer: the procfs buffer
103 * @fmt: the printf format
104 *
105 * Outputs the string on the procfs buffer just like printf().
106 *
107 * Returns the size of output string.
108 */
109int snd_iprintf(struct snd_info_buffer *buffer, const char *fmt, ...)
110{
111    va_list args;
112    int len, res;
113    int err = 0;
114
115    might_sleep();
116    if (buffer->stop || buffer->error)
117        return 0;
118    len = buffer->len - buffer->size;
119    va_start(args, fmt);
120    for (;;) {
121        va_list ap;
122        va_copy(ap, args);
123        res = vsnprintf(buffer->buffer + buffer->curr, len, fmt, ap);
124        va_end(ap);
125        if (res < len)
126            break;
127        err = resize_info_buffer(buffer, buffer->len + PAGE_SIZE);
128        if (err < 0)
129            break;
130        len = buffer->len - buffer->size;
131    }
132    va_end(args);
133
134    if (err < 0)
135        return err;
136    buffer->curr += res;
137    buffer->size += res;
138    return res;
139}
140
141EXPORT_SYMBOL(snd_iprintf);
142
143/*
144
145 */
146
147static struct proc_dir_entry *snd_proc_root;
148struct snd_info_entry *snd_seq_root;
149EXPORT_SYMBOL(snd_seq_root);
150
151#ifdef CONFIG_SND_OSSEMUL
152struct snd_info_entry *snd_oss_root;
153#endif
154
155static void snd_remove_proc_entry(struct proc_dir_entry *parent,
156                  struct proc_dir_entry *de)
157{
158    if (de)
159        remove_proc_entry(de->name, parent);
160}
161
162static loff_t snd_info_entry_llseek(struct file *file, loff_t offset, int orig)
163{
164    struct snd_info_private_data *data;
165    struct snd_info_entry *entry;
166    loff_t ret = -EINVAL, size;
167
168    data = file->private_data;
169    entry = data->entry;
170    mutex_lock(&entry->access);
171    if (entry->content == SNDRV_INFO_CONTENT_DATA &&
172        entry->c.ops->llseek) {
173        offset = entry->c.ops->llseek(entry,
174                          data->file_private_data,
175                          file, offset, orig);
176        goto out;
177    }
178    if (entry->content == SNDRV_INFO_CONTENT_DATA)
179        size = entry->size;
180    else
181        size = 0;
182    switch (orig) {
183    case SEEK_SET:
184        break;
185    case SEEK_CUR:
186        offset += file->f_pos;
187        break;
188    case SEEK_END:
189        if (!size)
190            goto out;
191        offset += size;
192        break;
193    default:
194        goto out;
195    }
196    if (offset < 0)
197        goto out;
198    if (size && offset > size)
199        offset = size;
200    file->f_pos = offset;
201    ret = offset;
202 out:
203    mutex_unlock(&entry->access);
204    return ret;
205}
206
207static ssize_t snd_info_entry_read(struct file *file, char __user *buffer,
208                   size_t count, loff_t * offset)
209{
210    struct snd_info_private_data *data;
211    struct snd_info_entry *entry;
212    struct snd_info_buffer *buf;
213    size_t size = 0;
214    loff_t pos;
215
216    data = file->private_data;
217    if (snd_BUG_ON(!data))
218        return -ENXIO;
219    pos = *offset;
220    if (pos < 0 || (long) pos != pos || (ssize_t) count < 0)
221        return -EIO;
222    if ((unsigned long) pos + (unsigned long) count < (unsigned long) pos)
223        return -EIO;
224    entry = data->entry;
225    switch (entry->content) {
226    case SNDRV_INFO_CONTENT_TEXT:
227        buf = data->rbuffer;
228        if (buf == NULL)
229            return -EIO;
230        if (pos >= buf->size)
231            return 0;
232        size = buf->size - pos;
233        size = min(count, size);
234        if (copy_to_user(buffer, buf->buffer + pos, size))
235            return -EFAULT;
236        break;
237    case SNDRV_INFO_CONTENT_DATA:
238        if (pos >= entry->size)
239            return 0;
240        if (entry->c.ops->read) {
241            size = entry->size - pos;
242            size = min(count, size);
243            size = entry->c.ops->read(entry,
244                          data->file_private_data,
245                          file, buffer, size, pos);
246        }
247        break;
248    }
249    if ((ssize_t) size > 0)
250        *offset = pos + size;
251    return size;
252}
253
254static ssize_t snd_info_entry_write(struct file *file, const char __user *buffer,
255                    size_t count, loff_t * offset)
256{
257    struct snd_info_private_data *data;
258    struct snd_info_entry *entry;
259    struct snd_info_buffer *buf;
260    ssize_t size = 0;
261    loff_t pos;
262
263    data = file->private_data;
264    if (snd_BUG_ON(!data))
265        return -ENXIO;
266    entry = data->entry;
267    pos = *offset;
268    if (pos < 0 || (long) pos != pos || (ssize_t) count < 0)
269        return -EIO;
270    if ((unsigned long) pos + (unsigned long) count < (unsigned long) pos)
271        return -EIO;
272    switch (entry->content) {
273    case SNDRV_INFO_CONTENT_TEXT:
274        buf = data->wbuffer;
275        if (buf == NULL)
276            return -EIO;
277        mutex_lock(&entry->access);
278        if (pos + count >= buf->len) {
279            if (resize_info_buffer(buf, pos + count)) {
280                mutex_unlock(&entry->access);
281                return -ENOMEM;
282            }
283        }
284        if (copy_from_user(buf->buffer + pos, buffer, count)) {
285            mutex_unlock(&entry->access);
286            return -EFAULT;
287        }
288        buf->size = pos + count;
289        mutex_unlock(&entry->access);
290        size = count;
291        break;
292    case SNDRV_INFO_CONTENT_DATA:
293        if (entry->c.ops->write && count > 0) {
294            size_t maxsize = entry->size - pos;
295            count = min(count, maxsize);
296            size = entry->c.ops->write(entry,
297                           data->file_private_data,
298                           file, buffer, count, pos);
299        }
300        break;
301    }
302    if ((ssize_t) size > 0)
303        *offset = pos + size;
304    return size;
305}
306
307static int snd_info_entry_open(struct inode *inode, struct file *file)
308{
309    struct snd_info_entry *entry;
310    struct snd_info_private_data *data;
311    struct snd_info_buffer *buffer;
312    struct proc_dir_entry *p;
313    int mode, err;
314
315    mutex_lock(&info_mutex);
316    p = PDE(inode);
317    entry = p == NULL ? NULL : (struct snd_info_entry *)p->data;
318    if (entry == NULL || ! entry->p) {
319        mutex_unlock(&info_mutex);
320        return -ENODEV;
321    }
322    if (!try_module_get(entry->module)) {
323        err = -EFAULT;
324        goto __error1;
325    }
326    mode = file->f_flags & O_ACCMODE;
327    if (mode == O_RDONLY || mode == O_RDWR) {
328        if ((entry->content == SNDRV_INFO_CONTENT_DATA &&
329             entry->c.ops->read == NULL)) {
330                err = -ENODEV;
331                goto __error;
332        }
333    }
334    if (mode == O_WRONLY || mode == O_RDWR) {
335        if ((entry->content == SNDRV_INFO_CONTENT_DATA &&
336             entry->c.ops->write == NULL)) {
337                err = -ENODEV;
338                goto __error;
339        }
340    }
341    data = kzalloc(sizeof(*data), GFP_KERNEL);
342    if (data == NULL) {
343        err = -ENOMEM;
344        goto __error;
345    }
346    data->entry = entry;
347    switch (entry->content) {
348    case SNDRV_INFO_CONTENT_TEXT:
349        if (mode == O_RDONLY || mode == O_RDWR) {
350            buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
351            if (buffer == NULL)
352                goto __nomem;
353            data->rbuffer = buffer;
354            buffer->len = PAGE_SIZE;
355            buffer->buffer = kmalloc(buffer->len, GFP_KERNEL);
356            if (buffer->buffer == NULL)
357                goto __nomem;
358        }
359        if (mode == O_WRONLY || mode == O_RDWR) {
360            buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
361            if (buffer == NULL)
362                goto __nomem;
363            data->wbuffer = buffer;
364            buffer->len = PAGE_SIZE;
365            buffer->buffer = kmalloc(buffer->len, GFP_KERNEL);
366            if (buffer->buffer == NULL)
367                goto __nomem;
368        }
369        break;
370    case SNDRV_INFO_CONTENT_DATA: /* data */
371        if (entry->c.ops->open) {
372            if ((err = entry->c.ops->open(entry, mode,
373                              &data->file_private_data)) < 0) {
374                kfree(data);
375                goto __error;
376            }
377        }
378        break;
379    }
380    file->private_data = data;
381    mutex_unlock(&info_mutex);
382    if (entry->content == SNDRV_INFO_CONTENT_TEXT &&
383        (mode == O_RDONLY || mode == O_RDWR)) {
384        if (entry->c.text.read) {
385            mutex_lock(&entry->access);
386            entry->c.text.read(entry, data->rbuffer);
387            mutex_unlock(&entry->access);
388        }
389    }
390    return 0;
391
392 __nomem:
393    if (data->rbuffer) {
394        kfree(data->rbuffer->buffer);
395        kfree(data->rbuffer);
396    }
397    if (data->wbuffer) {
398        kfree(data->wbuffer->buffer);
399        kfree(data->wbuffer);
400    }
401    kfree(data);
402    err = -ENOMEM;
403      __error:
404    module_put(entry->module);
405      __error1:
406    mutex_unlock(&info_mutex);
407    return err;
408}
409
410static int snd_info_entry_release(struct inode *inode, struct file *file)
411{
412    struct snd_info_entry *entry;
413    struct snd_info_private_data *data;
414    int mode;
415
416    mode = file->f_flags & O_ACCMODE;
417    data = file->private_data;
418    entry = data->entry;
419    switch (entry->content) {
420    case SNDRV_INFO_CONTENT_TEXT:
421        if (data->rbuffer) {
422            kfree(data->rbuffer->buffer);
423            kfree(data->rbuffer);
424        }
425        if (data->wbuffer) {
426            if (entry->c.text.write) {
427                entry->c.text.write(entry, data->wbuffer);
428                if (data->wbuffer->error) {
429                    snd_printk(KERN_WARNING "data write error to %s (%i)\n",
430                        entry->name,
431                        data->wbuffer->error);
432                }
433            }
434            kfree(data->wbuffer->buffer);
435            kfree(data->wbuffer);
436        }
437        break;
438    case SNDRV_INFO_CONTENT_DATA:
439        if (entry->c.ops->release)
440            entry->c.ops->release(entry, mode,
441                          data->file_private_data);
442        break;
443    }
444    module_put(entry->module);
445    kfree(data);
446    return 0;
447}
448
449static unsigned int snd_info_entry_poll(struct file *file, poll_table * wait)
450{
451    struct snd_info_private_data *data;
452    struct snd_info_entry *entry;
453    unsigned int mask;
454
455    data = file->private_data;
456    if (data == NULL)
457        return 0;
458    entry = data->entry;
459    mask = 0;
460    switch (entry->content) {
461    case SNDRV_INFO_CONTENT_DATA:
462        if (entry->c.ops->poll)
463            return entry->c.ops->poll(entry,
464                          data->file_private_data,
465                          file, wait);
466        if (entry->c.ops->read)
467            mask |= POLLIN | POLLRDNORM;
468        if (entry->c.ops->write)
469            mask |= POLLOUT | POLLWRNORM;
470        break;
471    }
472    return mask;
473}
474
475static long snd_info_entry_ioctl(struct file *file, unsigned int cmd,
476                unsigned long arg)
477{
478    struct snd_info_private_data *data;
479    struct snd_info_entry *entry;
480
481    data = file->private_data;
482    if (data == NULL)
483        return 0;
484    entry = data->entry;
485    switch (entry->content) {
486    case SNDRV_INFO_CONTENT_DATA:
487        if (entry->c.ops->ioctl)
488            return entry->c.ops->ioctl(entry,
489                           data->file_private_data,
490                           file, cmd, arg);
491        break;
492    }
493    return -ENOTTY;
494}
495
496static int snd_info_entry_mmap(struct file *file, struct vm_area_struct *vma)
497{
498    struct inode *inode = file->f_path.dentry->d_inode;
499    struct snd_info_private_data *data;
500    struct snd_info_entry *entry;
501
502    data = file->private_data;
503    if (data == NULL)
504        return 0;
505    entry = data->entry;
506    switch (entry->content) {
507    case SNDRV_INFO_CONTENT_DATA:
508        if (entry->c.ops->mmap)
509            return entry->c.ops->mmap(entry,
510                          data->file_private_data,
511                          inode, file, vma);
512        break;
513    }
514    return -ENXIO;
515}
516
517static const struct file_operations snd_info_entry_operations =
518{
519    .owner = THIS_MODULE,
520    .llseek = snd_info_entry_llseek,
521    .read = snd_info_entry_read,
522    .write = snd_info_entry_write,
523    .poll = snd_info_entry_poll,
524    .unlocked_ioctl = snd_info_entry_ioctl,
525    .mmap = snd_info_entry_mmap,
526    .open = snd_info_entry_open,
527    .release = snd_info_entry_release,
528};
529
530int __init snd_info_init(void)
531{
532    struct proc_dir_entry *p;
533
534    p = proc_mkdir("asound", NULL);
535    if (p == NULL)
536        return -ENOMEM;
537    snd_proc_root = p;
538#ifdef CONFIG_SND_OSSEMUL
539    {
540        struct snd_info_entry *entry;
541        if ((entry = snd_info_create_module_entry(THIS_MODULE, "oss", NULL)) == NULL)
542            return -ENOMEM;
543        entry->mode = S_IFDIR | S_IRUGO | S_IXUGO;
544        if (snd_info_register(entry) < 0) {
545            snd_info_free_entry(entry);
546            return -ENOMEM;
547        }
548        snd_oss_root = entry;
549    }
550#endif
551#if defined(CONFIG_SND_SEQUENCER) || defined(CONFIG_SND_SEQUENCER_MODULE)
552    {
553        struct snd_info_entry *entry;
554        if ((entry = snd_info_create_module_entry(THIS_MODULE, "seq", NULL)) == NULL)
555            return -ENOMEM;
556        entry->mode = S_IFDIR | S_IRUGO | S_IXUGO;
557        if (snd_info_register(entry) < 0) {
558            snd_info_free_entry(entry);
559            return -ENOMEM;
560        }
561        snd_seq_root = entry;
562    }
563#endif
564    snd_info_version_init();
565    snd_minor_info_init();
566    snd_minor_info_oss_init();
567    snd_card_info_init();
568    return 0;
569}
570
571int __exit snd_info_done(void)
572{
573    snd_card_info_done();
574    snd_minor_info_oss_done();
575    snd_minor_info_done();
576    snd_info_version_done();
577    if (snd_proc_root) {
578#if defined(CONFIG_SND_SEQUENCER) || defined(CONFIG_SND_SEQUENCER_MODULE)
579        snd_info_free_entry(snd_seq_root);
580#endif
581#ifdef CONFIG_SND_OSSEMUL
582        snd_info_free_entry(snd_oss_root);
583#endif
584        snd_remove_proc_entry(NULL, snd_proc_root);
585    }
586    return 0;
587}
588
589/*
590
591 */
592
593
594/*
595 * create a card proc file
596 * called from init.c
597 */
598int snd_info_card_create(struct snd_card *card)
599{
600    char str[8];
601    struct snd_info_entry *entry;
602
603    if (snd_BUG_ON(!card))
604        return -ENXIO;
605
606    sprintf(str, "card%i", card->number);
607    if ((entry = snd_info_create_module_entry(card->module, str, NULL)) == NULL)
608        return -ENOMEM;
609    entry->mode = S_IFDIR | S_IRUGO | S_IXUGO;
610    if (snd_info_register(entry) < 0) {
611        snd_info_free_entry(entry);
612        return -ENOMEM;
613    }
614    card->proc_root = entry;
615    return 0;
616}
617
618/*
619 * register the card proc file
620 * called from init.c
621 */
622int snd_info_card_register(struct snd_card *card)
623{
624    struct proc_dir_entry *p;
625
626    if (snd_BUG_ON(!card))
627        return -ENXIO;
628
629    if (!strcmp(card->id, card->proc_root->name))
630        return 0;
631
632    p = proc_symlink(card->id, snd_proc_root, card->proc_root->name);
633    if (p == NULL)
634        return -ENOMEM;
635    card->proc_root_link = p;
636    return 0;
637}
638
639/*
640 * called on card->id change
641 */
642void snd_info_card_id_change(struct snd_card *card)
643{
644    mutex_lock(&info_mutex);
645    if (card->proc_root_link) {
646        snd_remove_proc_entry(snd_proc_root, card->proc_root_link);
647        card->proc_root_link = NULL;
648    }
649    if (strcmp(card->id, card->proc_root->name))
650        card->proc_root_link = proc_symlink(card->id,
651                            snd_proc_root,
652                            card->proc_root->name);
653    mutex_unlock(&info_mutex);
654}
655
656/*
657 * de-register the card proc file
658 * called from init.c
659 */
660void snd_info_card_disconnect(struct snd_card *card)
661{
662    if (!card)
663        return;
664    mutex_lock(&info_mutex);
665    if (card->proc_root_link) {
666        snd_remove_proc_entry(snd_proc_root, card->proc_root_link);
667        card->proc_root_link = NULL;
668    }
669    if (card->proc_root)
670        snd_info_disconnect(card->proc_root);
671    mutex_unlock(&info_mutex);
672}
673
674/*
675 * release the card proc file resources
676 * called from init.c
677 */
678int snd_info_card_free(struct snd_card *card)
679{
680    if (!card)
681        return 0;
682    snd_info_free_entry(card->proc_root);
683    card->proc_root = NULL;
684    return 0;
685}
686
687
688/**
689 * snd_info_get_line - read one line from the procfs buffer
690 * @buffer: the procfs buffer
691 * @line: the buffer to store
692 * @len: the max. buffer size - 1
693 *
694 * Reads one line from the buffer and stores the string.
695 *
696 * Returns zero if successful, or 1 if error or EOF.
697 */
698int snd_info_get_line(struct snd_info_buffer *buffer, char *line, int len)
699{
700    int c = -1;
701
702    if (len <= 0 || buffer->stop || buffer->error)
703        return 1;
704    while (--len > 0) {
705        c = buffer->buffer[buffer->curr++];
706        if (c == '\n') {
707            if (buffer->curr >= buffer->size)
708                buffer->stop = 1;
709            break;
710        }
711        *line++ = c;
712        if (buffer->curr >= buffer->size) {
713            buffer->stop = 1;
714            break;
715        }
716    }
717    while (c != '\n' && !buffer->stop) {
718        c = buffer->buffer[buffer->curr++];
719        if (buffer->curr >= buffer->size)
720            buffer->stop = 1;
721    }
722    *line = '\0';
723    return 0;
724}
725
726EXPORT_SYMBOL(snd_info_get_line);
727
728/**
729 * snd_info_get_str - parse a string token
730 * @dest: the buffer to store the string token
731 * @src: the original string
732 * @len: the max. length of token - 1
733 *
734 * Parses the original string and copy a token to the given
735 * string buffer.
736 *
737 * Returns the updated pointer of the original string so that
738 * it can be used for the next call.
739 */
740const char *snd_info_get_str(char *dest, const char *src, int len)
741{
742    int c;
743
744    while (*src == ' ' || *src == '\t')
745        src++;
746    if (*src == '"' || *src == '\'') {
747        c = *src++;
748        while (--len > 0 && *src && *src != c) {
749            *dest++ = *src++;
750        }
751        if (*src == c)
752            src++;
753    } else {
754        while (--len > 0 && *src && *src != ' ' && *src != '\t') {
755            *dest++ = *src++;
756        }
757    }
758    *dest = 0;
759    while (*src == ' ' || *src == '\t')
760        src++;
761    return src;
762}
763
764EXPORT_SYMBOL(snd_info_get_str);
765
766/**
767 * snd_info_create_entry - create an info entry
768 * @name: the proc file name
769 *
770 * Creates an info entry with the given file name and initializes as
771 * the default state.
772 *
773 * Usually called from other functions such as
774 * snd_info_create_card_entry().
775 *
776 * Returns the pointer of the new instance, or NULL on failure.
777 */
778static struct snd_info_entry *snd_info_create_entry(const char *name)
779{
780    struct snd_info_entry *entry;
781    entry = kzalloc(sizeof(*entry), GFP_KERNEL);
782    if (entry == NULL)
783        return NULL;
784    entry->name = kstrdup(name, GFP_KERNEL);
785    if (entry->name == NULL) {
786        kfree(entry);
787        return NULL;
788    }
789    entry->mode = S_IFREG | S_IRUGO;
790    entry->content = SNDRV_INFO_CONTENT_TEXT;
791    mutex_init(&entry->access);
792    INIT_LIST_HEAD(&entry->children);
793    INIT_LIST_HEAD(&entry->list);
794    return entry;
795}
796
797/**
798 * snd_info_create_module_entry - create an info entry for the given module
799 * @module: the module pointer
800 * @name: the file name
801 * @parent: the parent directory
802 *
803 * Creates a new info entry and assigns it to the given module.
804 *
805 * Returns the pointer of the new instance, or NULL on failure.
806 */
807struct snd_info_entry *snd_info_create_module_entry(struct module * module,
808                           const char *name,
809                           struct snd_info_entry *parent)
810{
811    struct snd_info_entry *entry = snd_info_create_entry(name);
812    if (entry) {
813        entry->module = module;
814        entry->parent = parent;
815    }
816    return entry;
817}
818
819EXPORT_SYMBOL(snd_info_create_module_entry);
820
821/**
822 * snd_info_create_card_entry - create an info entry for the given card
823 * @card: the card instance
824 * @name: the file name
825 * @parent: the parent directory
826 *
827 * Creates a new info entry and assigns it to the given card.
828 *
829 * Returns the pointer of the new instance, or NULL on failure.
830 */
831struct snd_info_entry *snd_info_create_card_entry(struct snd_card *card,
832                         const char *name,
833                         struct snd_info_entry * parent)
834{
835    struct snd_info_entry *entry = snd_info_create_entry(name);
836    if (entry) {
837        entry->module = card->module;
838        entry->card = card;
839        entry->parent = parent;
840    }
841    return entry;
842}
843
844EXPORT_SYMBOL(snd_info_create_card_entry);
845
846static void snd_info_disconnect(struct snd_info_entry *entry)
847{
848    struct list_head *p, *n;
849    struct proc_dir_entry *root;
850
851    list_for_each_safe(p, n, &entry->children) {
852        snd_info_disconnect(list_entry(p, struct snd_info_entry, list));
853    }
854
855    if (! entry->p)
856        return;
857    list_del_init(&entry->list);
858    root = entry->parent == NULL ? snd_proc_root : entry->parent->p;
859    snd_BUG_ON(!root);
860    snd_remove_proc_entry(root, entry->p);
861    entry->p = NULL;
862}
863
864static int snd_info_dev_free_entry(struct snd_device *device)
865{
866    struct snd_info_entry *entry = device->device_data;
867    snd_info_free_entry(entry);
868    return 0;
869}
870
871static int snd_info_dev_register_entry(struct snd_device *device)
872{
873    struct snd_info_entry *entry = device->device_data;
874    return snd_info_register(entry);
875}
876
877/**
878 * snd_card_proc_new - create an info entry for the given card
879 * @card: the card instance
880 * @name: the file name
881 * @entryp: the pointer to store the new info entry
882 *
883 * Creates a new info entry and assigns it to the given card.
884 * Unlike snd_info_create_card_entry(), this function registers the
885 * info entry as an ALSA device component, so that it can be
886 * unregistered/released without explicit call.
887 * Also, you don't have to register this entry via snd_info_register(),
888 * since this will be registered by snd_card_register() automatically.
889 *
890 * The parent is assumed as card->proc_root.
891 *
892 * For releasing this entry, use snd_device_free() instead of
893 * snd_info_free_entry().
894 *
895 * Returns zero if successful, or a negative error code on failure.
896 */
897int snd_card_proc_new(struct snd_card *card, const char *name,
898              struct snd_info_entry **entryp)
899{
900    static struct snd_device_ops ops = {
901        .dev_free = snd_info_dev_free_entry,
902        .dev_register = snd_info_dev_register_entry,
903        /* disconnect is done via snd_info_card_disconnect() */
904    };
905    struct snd_info_entry *entry;
906    int err;
907
908    entry = snd_info_create_card_entry(card, name, card->proc_root);
909    if (! entry)
910        return -ENOMEM;
911    if ((err = snd_device_new(card, SNDRV_DEV_INFO, entry, &ops)) < 0) {
912        snd_info_free_entry(entry);
913        return err;
914    }
915    if (entryp)
916        *entryp = entry;
917    return 0;
918}
919
920EXPORT_SYMBOL(snd_card_proc_new);
921
922/**
923 * snd_info_free_entry - release the info entry
924 * @entry: the info entry
925 *
926 * Releases the info entry. Don't call this after registered.
927 */
928void snd_info_free_entry(struct snd_info_entry * entry)
929{
930    if (entry == NULL)
931        return;
932    if (entry->p) {
933        mutex_lock(&info_mutex);
934        snd_info_disconnect(entry);
935        mutex_unlock(&info_mutex);
936    }
937    kfree(entry->name);
938    if (entry->private_free)
939        entry->private_free(entry);
940    kfree(entry);
941}
942
943EXPORT_SYMBOL(snd_info_free_entry);
944
945/**
946 * snd_info_register - register the info entry
947 * @entry: the info entry
948 *
949 * Registers the proc info entry.
950 *
951 * Returns zero if successful, or a negative error code on failure.
952 */
953int snd_info_register(struct snd_info_entry * entry)
954{
955    struct proc_dir_entry *root, *p = NULL;
956
957    if (snd_BUG_ON(!entry))
958        return -ENXIO;
959    root = entry->parent == NULL ? snd_proc_root : entry->parent->p;
960    mutex_lock(&info_mutex);
961    p = create_proc_entry(entry->name, entry->mode, root);
962    if (!p) {
963        mutex_unlock(&info_mutex);
964        return -ENOMEM;
965    }
966    if (!S_ISDIR(entry->mode))
967        p->proc_fops = &snd_info_entry_operations;
968    p->size = entry->size;
969    p->data = entry;
970    entry->p = p;
971    if (entry->parent)
972        list_add_tail(&entry->list, &entry->parent->children);
973    mutex_unlock(&info_mutex);
974    return 0;
975}
976
977EXPORT_SYMBOL(snd_info_register);
978
979/*
980
981 */
982
983static struct snd_info_entry *snd_info_version_entry;
984
985static void snd_info_version_read(struct snd_info_entry *entry, struct snd_info_buffer *buffer)
986{
987    snd_iprintf(buffer,
988            "Advanced Linux Sound Architecture Driver Version "
989            CONFIG_SND_VERSION CONFIG_SND_DATE ".\n"
990           );
991}
992
993static int __init snd_info_version_init(void)
994{
995    struct snd_info_entry *entry;
996
997    entry = snd_info_create_module_entry(THIS_MODULE, "version", NULL);
998    if (entry == NULL)
999        return -ENOMEM;
1000    entry->c.text.read = snd_info_version_read;
1001    if (snd_info_register(entry) < 0) {
1002        snd_info_free_entry(entry);
1003        return -ENOMEM;
1004    }
1005    snd_info_version_entry = entry;
1006    return 0;
1007}
1008
1009static int __exit snd_info_version_done(void)
1010{
1011    snd_info_free_entry(snd_info_version_entry);
1012    return 0;
1013}
1014
1015#endif /* CONFIG_PROC_FS */
1016

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