summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorDenys Vlasenko <vda.linux@googlemail.com>2011-02-11 21:01:33 (GMT)
committer Denys Vlasenko <vda.linux@googlemail.com>2011-02-11 21:01:33 (GMT)
commitf9af3756687840c76d8ba4e34b33916b6e36ca61 (patch)
treeeb5e724f14d3327bec15b6306598d920b2ab45ad
parent8766a791e847fdf1f3f00222f18c18833f40abda (diff)
downloadbusybox-f9af3756687840c76d8ba4e34b33916b6e36ca61.tar.gz
busybox-f9af3756687840c76d8ba4e34b33916b6e36ca61.tar.bz2
wget: explain clearerr more clearly
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
-rw-r--r--networking/wget.c11
1 files changed, 10 insertions, 1 deletions
diff --git a/networking/wget.c b/networking/wget.c
index 4868864..673113b 100644
--- a/networking/wget.c
+++ b/networking/wget.c
@@ -466,6 +466,14 @@ static void NOINLINE retrieve_file_data(FILE *dfp, int output_fd)
polldata.fd = fileno(dfp);
polldata.events = POLLIN | POLLPRI;
+
+ /* Must use nonblocking I/O, otherwise fread will loop
+ * and *block* until it reads full buffer,
+ * which messes up progress bar and/or timing out.
+ * Because of nonblocking I/O, we need to dance
+ * very carefully around EAGAIN. See explanation at
+ * clearerr() call.
+ */
ndelay_on(polldata.fd);
#endif
progress_meter(PROGRESS_START);
@@ -504,7 +512,7 @@ static void NOINLINE retrieve_file_data(FILE *dfp, int output_fd)
/* 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.
@@ -515,6 +523,7 @@ static void NOINLINE retrieve_file_data(FILE *dfp, int output_fd)
*/
clearerr(dfp);
errno = 0;
+#endif
n = fread(G.wget_buf, 1, rdsz, dfp);
/* man fread:
* If error occurs, or EOF is reached, the return value