[PATCH v3 08/19] write_or_die: raise SIGPIPE when we get EPIPE
- From
Jeff King <peff@peff.net>
- Date
- Feb 20, 2013, 20:01 UTC
- Message-ID
- <20130220200136.GH25647@sigill.intra.peff.net>
- In-Reply-To
- <20130220195147.GA25332@sigill.intra.peff.net>
The write_or_die function will always die on an error, including EPIPE. However, it currently treats EPIPE specially by suppressing any error message, and by exiting with exit code 0.
Suppressing the error message makes some sense; a pipe death may just be a sign that the other side is not interested in what we have to say. However, exiting with a successful error code is not a good idea, as write_or_die is frequently used in cases where we want to be careful about having written all of the output, and we may need to signal to our caller that we have done so (e.g., you would not want a push whose other end has hung up to report success).
This distinction doesn't typically matter in git, because we do not ignore SIGPIPE in the first place. Which means that we will not get EPIPE, but instead will just die when we get a SIGPIPE. But it's possible for a default handler to be set by a parent process, or for us to add a callsite inside one of our few SIGPIPE-ignoring blocks of code.
This patch converts write_or_die to actually raise SIGPIPE when we see EPIPE, rather than exiting with zero. This brings the behavior in line with the "normal" case that we die from SIGPIPE (and any callers who want to check why we died will see the same thing). We also give the same treatment to other related functions, including write_or_whine_pipe and maybe_flush_or_die.
Signed-off-by: Jeff King <peff@peff.net> --- write_or_die.c | 19 +++++++++++++------ 1 file changed, 13 insertions(+), 6 deletions(-)
diff --git a/write_or_die.c b/write_or_die.c index 960f448..b50f99a 100644 --- a/write_or_die.c +++ b/write_or_die.c @@ -1,5 +1,15 @@ #include "cache.h" +static void check_pipe(int err) +{ + if (err == EPIPE) { + signal(SIGPIPE, SIG_DFL); + raise(SIGPIPE); + /* Should never happen, but just in case... */ + exit(141); + } +} + /* * Some cases use stdio, but want to flush after the write * to get error handling (and to get better interactive @@ -34,8 +44,7 @@ void maybe_flush_or_die(FILE *f, const char *desc) return; } if (fflush(f)) { - if (errno == EPIPE) - exit(0); + check_pipe(errno); die_errno("write failure on '%s'", desc); } } @@ -50,8 +59,7 @@ void write_or_die(int fd, const void *buf, size_t count) void write_or_die(int fd, const void *buf, size_t count) { if (write_in_full(fd, buf, count) < 0) { - if (errno == EPIPE) - exit(0); + check_pipe(errno); die_errno("write error"); } } @@ -59,8 +67,7 @@ int write_or_whine_pipe(int fd, const void *buf, size_t count, const char *msg) int write_or_whine_pipe(int fd, const void *buf, size_t count, const char *msg) { if (write_in_full(fd, buf, count) < 0) { - if (errno == EPIPE) - exit(0); + check_pipe(errno); fprintf(stderr, "%s: write error (%s)\n", msg, strerror(errno)); return 0;
-- 1.8.2.rc0.9.g352092c