pcm: file plugin - implement safe_write

The syscalls may return EINTR when a signal is handled.
Implement safe_write() function which does simple write
retry.

Signed-off-by: Jaroslav Kysela <perex@perex.cz>

diff --git a/src/pcm/pcm_file.c b/src/pcm/pcm_file.c
index a02b2dc01d388104f4f7df3fc35dc342e82e9c32..7709a5549dbe18cb3b4f37e865ee997d2481e724 100644 (file)
--- a/src/pcm/pcm_file.c
+++ b/src/pcm/pcm_file.c
@@ -100,6 +100,21 @@ typedef struct {
 #define TO_LE16(x)     bswap_16(x)
 #endif
 
+static ssize_t safe_write(int fd, const void *buf, size_t len)
+{
+       while (1) {
+               ssize_t r = write(fd, buf, len);
+               if (r < 0) {
+                       if (errno == EINTR)
+                               continue;
+                       if (errno == EPIPE)
+                               return -EIO;
+                       return -errno;
+               }
+               return r;
+       }
+}
+
 static int snd_pcm_file_append_value(char **string_p, char **index_ch_p,
                int *len_p, const char *value)
 {
@@ -339,15 +354,15 @@ static int write_wav_header(snd_pcm_t *pcm)
        
        setup_wav_header(pcm, &file->wav_header);
 
-       res = write(file->fd, header, sizeof(header));
+       res = safe_write(file->fd, header, sizeof(header));
        if (res != sizeof(header))
                goto write_error;
 
-       res = write(file->fd, &file->wav_header, sizeof(file->wav_header));
+       res = safe_write(file->fd, &file->wav_header, sizeof(file->wav_header));
        if (res != sizeof(file->wav_header))
                goto write_error;
 
-       res = write(file->fd, header2, sizeof(header2));
+       res = safe_write(file->fd, header2, sizeof(header2));
        if (res != sizeof(header2))
                goto write_error;
 
@@ -381,7 +396,7 @@ static void fixup_wav_header(snd_pcm_t *pcm)
                len = (file->filelen + 0x24) > 0x7fffffff ?
                        0x7fffffff : (int)(file->filelen + 0x24);
                len = TO_LE32(len);
-               ret = write(file->fd, &len, 4);
+               ret = safe_write(file->fd, &len, 4);
                if (ret < 0)
                        return;
        }
@@ -390,7 +405,7 @@ static void fixup_wav_header(snd_pcm_t *pcm)
                len = file->filelen > 0x7fffffff ?
                        0x7fffffff : (int)file->filelen;
                len = TO_LE32(len);
-               ret = write(file->fd, &len, 4);
+               ret = safe_write(file->fd, &len, 4);
                if (ret < 0)
                        return;
        }
@@ -421,9 +436,8 @@ static int snd_pcm_file_write_bytes(snd_pcm_t *pcm, size_t bytes)
                size_t cont = file->wbuf_size_bytes - file->file_ptr_bytes;
                if (n > cont)
                        n = cont;
-               err = write(file->fd, file->wbuf + file->file_ptr_bytes, n);
+               err = safe_write(file->fd, file->wbuf + file->file_ptr_bytes, n);
                if (err < 0) {
-                       err = -errno;
                        file->wbuf_used_bytes = 0;
                        file->file_ptr_bytes = 0;
                        SYSERR("%s write failed, file data may be corrupt", file->fname);