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* grub-core/io/bufio.c (grub_bufio_read): Fix handling of corner cases.

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Vladimir 'phcoder' Serbinenko 2011-12-25 15:43:15 +01:00
parent bbc47747ad
commit cc4fddf5f5
2 changed files with 22 additions and 22 deletions
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4
ChangeLog
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@ -1,3 +1,7 @@
2011-12-25 Vladimir Serbinenko <phcoder@gmail.com>
* grub-core/io/bufio.c (grub_bufio_read): Fix handling of corner cases.
2011-12-25 Vladimir Serbinenko <phcoder@gmail.com>
* docs/grub.texi (Filesystems): Mention AFS.

40
grub-core/io/bufio.c
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@ -107,7 +107,9 @@ static grub_ssize_t
grub_bufio_read (grub_file_t file, char *buf, grub_size_t len)
{
grub_size_t res = 0;
grub_off_t next_buf;
grub_bufio_t bufio = file->data;
grub_ssize_t really_read;
if (file->size == GRUB_FILE_SIZE_UNKNOWN)
file->size = bufio->file->size;
@ -130,22 +132,19 @@ grub_bufio_read (grub_file_t file, char *buf, grub_size_t len)
buf += n;
}
if (! len)
if (len == 0)
return res;
/* Need to read some more. */
bufio->buffer_at = grub_divmod64 (file->offset + res + len, bufio->block_size,
0) * bufio->block_size;
next_buf = (file->offset + res + len - 1) & ~((grub_off_t) bufio->block_size - 1);
/* Now read between file->offset + res and bufio->buffer_at. */
if (file->offset + res < bufio->buffer_at)
if (file->offset + res < next_buf)
{
grub_size_t read_now;
grub_ssize_t really_read;
read_now = bufio->buffer_at - (file->offset + res);
read_now = next_buf - (file->offset + res);
grub_file_seek (bufio->file, file->offset + res);
really_read = grub_file_read (bufio->file, buf, read_now);
if (grub_errno)
if (really_read < 0)
return -1;
if (file->size == GRUB_FILE_SIZE_UNKNOWN)
file->size = bufio->file->size;
@ -168,24 +167,21 @@ grub_bufio_read (grub_file_t file, char *buf, grub_size_t len)
}
/* Read into buffer. */
grub_file_seek (bufio->file, bufio->buffer_at);
bufio->buffer_len = grub_file_read (bufio->file, bufio->buffer,
bufio->block_size);
if (grub_errno)
grub_file_seek (bufio->file, next_buf);
really_read = grub_file_read (bufio->file, bufio->buffer,
bufio->block_size);
if (really_read < 0)
return -1;
bufio->buffer_at = next_buf;
bufio->buffer_len = really_read;
if (file->size == GRUB_FILE_SIZE_UNKNOWN)
file->size = bufio->file->size;
if (len < bufio->buffer_len)
{
grub_memcpy (buf, &bufio->buffer[0], len);
res += len;
}
else
{
grub_memcpy (buf, &bufio->buffer[0], bufio->buffer_len);
res += bufio->buffer_len;
}
if (len > bufio->buffer_len)
len = bufio->buffer_len;
grub_memcpy (buf, &bufio->buffer[file->offset + res - next_buf], len);
res += len;
return res;
}