path: root/run-command.c
diff options
authorJonathan Nieder <>2011-04-20 10:40:05 (GMT)
committerJunio C Hamano <>2011-04-20 17:09:26 (GMT)
commita111eb7808bfdb90286e54b9ccdaea4f3bec3102 (patch)
tree8014a5169540c9e9d7f6332a1cc7a569726bfd5f /run-command.c
parentc0f19bf3b9c42036722396ee26d2c173d6abf761 (diff)
run-command: handle short writes and EINTR in die_child
If start_command fails after forking and before exec finishes, there is not much use in noticing an I/O error on top of that. finish_command will notice that the child exited with nonzero status anyway. So as noted in v1.7.0.3~20^2 (run-command.c: fix build warnings on Ubuntu, 2010-01-30) and v1.7.5-rc0~29^2 (2011-03-16), it is safe to ignore errors from write in this codepath. Even so, the result from write contains useful information: it tells us if the write was cancelled by a signal (EINTR) or was only partially completed (e.g., when writing to an almost-full pipe). Let's use write_in_full to loop until the desired number of bytes have been written (still ignoring errors if that fails). As a happy side effect, the assignment to a dummy variable to appease gcc -D_FORTIFY_SOURCE is no longer needed. xwrite and write_in_full check the return value from write(2). Noticed with gcc -Wunused-but-set-variable. Signed-off-by: Jonathan Nieder <> Signed-off-by: Junio C Hamano <>
Diffstat (limited to 'run-command.c')
1 files changed, 9 insertions, 6 deletions
diff --git a/run-command.c b/run-command.c
index f91e446..70e8a24 100644
--- a/run-command.c
+++ b/run-command.c
@@ -67,21 +67,24 @@ static int child_notifier = -1;
static void notify_parent(void)
- ssize_t unused;
- unused = write(child_notifier, "", 1);
+ /*
+ * execvp failed. If possible, we'd like to let start_command
+ * know, so failures like ENOENT can be handled right away; but
+ * otherwise, finish_command will still report the error.
+ */
+ xwrite(child_notifier, "", 1);
static NORETURN void die_child(const char *err, va_list params)
char msg[4096];
- ssize_t unused;
int len = vsnprintf(msg, sizeof(msg), err, params);
if (len > sizeof(msg))
len = sizeof(msg);
- unused = write(child_err, "fatal: ", 7);
- unused = write(child_err, msg, len);
- unused = write(child_err, "\n", 1);
+ write_in_full(child_err, "fatal: ", 7);
+ write_in_full(child_err, msg, len);
+ write_in_full(child_err, "\n", 1);