8766a791e
Denys Vlasenko
2011-02-11
Subject
wget: correctly handle rare case when we get EAGAIN _on first_ read
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networking/wget.c+26 -6
| @@ -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); | |