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wget: correctly handle rare case when we get EAGAIN _on first_ read

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Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko 2011-02-11 21:42:00 +01:00
parent ab8d00d64f
commit 8766a791e8
1 changed files with 26 additions and 6 deletions
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32
networking/wget.c
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@ -487,6 +487,7 @@ static void NOINLINE retrieve_file_data(FILE *dfp, int output_fd)
rdsz = (unsigned)G.content_len;
}
}
#if ENABLE_FEATURE_WGET_STATUSBAR || ENABLE_FEATURE_WGET_TIMEOUT
# if ENABLE_FEATURE_WGET_TIMEOUT
second_cnt = G.timeout_seconds;
@ -497,22 +498,41 @@ static void NOINLINE retrieve_file_data(FILE *dfp, int output_fd)
# if ENABLE_FEATURE_WGET_TIMEOUT
if (second_cnt != 0 && --second_cnt == 0) {
progress_meter(PROGRESS_END);
bb_perror_msg_and_die("download timed out");
bb_error_msg_and_die("download timed out");
}
# endif
/* Needed for "stalled" indicator */
progress_meter(PROGRESS_BUMP);
}
#endif
/* fread internally uses read loop, which in our case
* is usually exited when we get EAGAIN.
* In this case, libc sets error marker on the stream.
* Need to clear it before next fread to avoid possible
* rare false positive ferror below. Rare because usually
* fread gets more than zero bytes, and we don't fall
* into if (n <= 0) ...
*/
clearerr(dfp);
errno = 0;
n = fread(G.wget_buf, 1, rdsz, dfp);
/* man fread:
* If error occurs, or EOF is reached, the return value
* is a short item count (or zero).
* fread does not distinguish between EOF and error.
*/
if (n <= 0) {
if (ferror(dfp)) {
/* perror will not work: ferror doesn't set errno */
bb_error_msg_and_die(bb_msg_read_error);
}
break;
#if ENABLE_FEATURE_WGET_STATUSBAR || ENABLE_FEATURE_WGET_TIMEOUT
if (errno == EAGAIN) /* poll lied, there is no data? */
continue; /* yes */
#endif
if (ferror(dfp))
bb_perror_msg_and_die(bb_msg_read_error);
break; /* EOF, not error */
}
xwrite(output_fd, G.wget_buf, n);
#if ENABLE_FEATURE_WGET_STATUSBAR
G.transferred += n;
progress_meter(PROGRESS_BUMP);