commit 86de065aee642585e092969c69681f7e8847a648 Author: Alexander Færøy ahf@torproject.org Date: Wed Mar 8 00:12:06 2017 +0100

Use read(2) instead of fgets(3) when reading process output.

This patch modifies `tor_read_all_handle()` to use read(2) instead of fgets(3) when reading the stdout from the child process. This should eliminate the race condition that can be triggered in the 'slow/util/*' tests on slower machines running OpenBSD, FreeBSD and HardenedBSD.

See: https://bugs.torproject.org/21654 --- src/common/util.c | 42 ++++++++++++++++++------------------------ 1 file changed, 18 insertions(+), 24 deletions(-)

diff --git a/src/common/util.c b/src/common/util.c index a69d887..e2ad5ff 100644 --- a/src/common/util.c +++ b/src/common/util.c @@ -5010,7 +5010,7 @@ tor_read_all_handle(FILE *h, char *buf, size_t count, int *eof) { size_t numread = 0; - char *retval; + ssize_t result;

if (eof) *eof = 0; @@ -5019,33 +5019,27 @@ tor_read_all_handle(FILE *h, char *buf, size_t count, return -1;

while (numread != count) { - /* Use fgets because that is what we use in log_from_pipe() */ - retval = tor_fgets(buf+numread, (int)(count-numread), h); - if (NULL == retval) { - if (feof(h)) { - log_debug(LD_GENERAL, "fgets() reached end of file"); - if (eof) - *eof = 1; + result = read(fileno(h), buf+numread, count-numread); + + if (result == 0) { + log_debug(LD_GENERAL, "read() reached end of file"); + if (eof) + *eof = 1; + break; + } else if (result < 0 && errno == EAGAIN) { + if (process) + continue; + else break; - } else { - if (EAGAIN == errno) { - if (process) - continue; - else - break; - } else { - log_warn(LD_GENERAL, "fgets() from handle failed: %s", - strerror(errno)); - return -1; - } - } + } else if (result < 0) { + log_warn(LD_GENERAL, "read() failed: %s", strerror(errno)); + return -1; } - tor_assert(retval != NULL); - tor_assert(strlen(retval) + numread <= count); - numread += strlen(retval); + + numread += result; }

- log_debug(LD_GENERAL, "fgets() read %d bytes from handle", (int)numread); + log_debug(LD_GENERAL, "read() read %d bytes from handle", (int)numread); return (ssize_t)numread; } #endif