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 <jrnieder@xxxxxxxxx>
---
Changes from v1:
- rewrite the commit message from the pov of a person who does not
care about this patch's origin as a brown paper bag
- drop the "if"s. If the fussy compiler/library combination was
right in some strange sense after all, then it does not make much
sense to take the opportunity to make another token effort to
appease it as a preventative step.
run-command.c | 15 +++++++++------
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);
exit(128);
}
#endif
--
1.7.5.rc2
--
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