Hello! I've been investigating an issue on my Alpine linux server running cgit 1.2.3-r2. When I call the CGI program and redirect to a regular file (or just output to tty), the output is correct, however if the standard output is a pipe, the output is truncated at 65523 bytes.
Here is the end of the diff between strace outputs: open("/var/cache/cgit/a1000000", O_RDONLY|O_LARGEFILE) = 3 fstat(3, {st_mode=S_IFREG|0600, st_size=157003, ...}) = 0 read(3, "st/tree/st.c\0Content-Type: text/"..., 4096) = 4096 -sendfile(1, 3, [13] => [157003], 156990) = 156990 +sendfile(1, 3, [13] => [65536], 156990) = 65523 close(3) = 0 exit_group(0) = ? +++ exited with 0 +++ I have managed to work around the issue by wrapping cgit and redirecting to a temporary file. Looks like the sendfile call comes from cache.c:95 - https://git.zx2c4.com/cgit/tree/cache.c?h=v1.2.3&id=55fa25adb097d2681607d8b0f51a0c393cc9af1a#n95 senfile(2) says that a successful call may write fewer bytes than requested; the caller should be prepared to retry the call if there were unsent bytes