From 0f9c90e0edd27d2db04d48e7bd98bb46d2c4a918 Mon Sep 17 00:00:00 2001 From: Matt Widmann Date: Sat, 25 Nov 2017 13:59:07 -0800 Subject: io: retry fgets on EINTR (#7632) The calls to `fgets` in `src/nvim/if_cscope.c` (and elsewhere) can show communication errors to the user if a signal is delivered during its system calls. For plugins that proxy subprocess output into cscope requests, a `SIGCHLD` might *always* interfere with calls into `fgets`. To see this in a debugger, put a breakpoint on `cs_reading_emsg` and watch signals come in (with lldb, using `process handle --notify true --pass true`). Next, run a subcommand from neovim that calls through cscope when it returns. A tag picker plugin, like vim-picker and fzy, with `cscopetag` and `cscopetagorder=0` set, reproduced this reliably. The breakpoint will hit after a `SIGCHLD` is delivered, and `errno` will be set to 4, `EINTR`. The caller of `fgets` should retry when `NULL` is returned with `errno` set to `EINTR`. --- src/nvim/if_cscope.c | 17 +++++++++++++++-- 1 file changed, 15 insertions(+), 2 deletions(-) (limited to 'src/nvim/if_cscope.c') diff --git a/src/nvim/if_cscope.c b/src/nvim/if_cscope.c index 0f9ecdf2d7..21e4b84074 100644 --- a/src/nvim/if_cscope.c +++ b/src/nvim/if_cscope.c @@ -553,9 +553,15 @@ static int cs_cnt_matches(size_t idx) char *buf = xmalloc(CSREAD_BUFSIZE); for (;; ) { + errno = 0; if (!fgets(buf, CSREAD_BUFSIZE, csinfo[idx].fr_fp)) { - if (feof(csinfo[idx].fr_fp)) + if (errno == EINTR) { + continue; + } + + if (feof(csinfo[idx].fr_fp)) { errno = EIO; + } cs_reading_emsg(idx); @@ -1381,9 +1387,16 @@ static char *cs_parse_results(size_t cnumber, char *buf, int bufsize, char *p; char *name; +retry: + errno = 0; if (fgets(buf, bufsize, csinfo[cnumber].fr_fp) == NULL) { - if (feof(csinfo[cnumber].fr_fp)) + if (errno == EINTR) { + goto retry; + } + + if (feof(csinfo[cnumber].fr_fp)) { errno = EIO; + } cs_reading_emsg(cnumber); -- cgit