git/common-main.c

#include "cache.h"
#include "exec_cmd.h"

/*
 * Many parts of Git have subprograms communicate via pipe, expect the
 * upstream of a pipe to die with SIGPIPE when the downstream of a
 * pipe does not need to read all that is written.  Some third-party
 * programs that ignore or block SIGPIPE for their own reason forget
 * to restore SIGPIPE handling to the default before spawning Git and
 * break this carefully orchestrated machinery.
 *
 * Restore the way SIGPIPE is handled to default, which is what we
 * expect.
 */
static void restore_sigpipe_to_default(void)
{
	sigset_t unblock;

	sigemptyset(&unblock);
	sigaddset(&unblock, SIGPIPE);
	sigprocmask(SIG_UNBLOCK, &unblock, NULL);
	signal(SIGPIPE, SIG_DFL);
}

int main(int argc, char **av)
{
	/*
	 * This const trickery is explained in
	 * 84d32bf7678259c08406571cd6ce4b7a6724dcba
	 */
	const char **argv = (const char **)av;

	/*
	 * Always open file descriptors 0/1/2 to avoid clobbering files
	 * in die().  It also avoids messing up when the pipes are dup'ed
	 * onto stdin/stdout/stderr in the child processes we spawn.
	 */
	sanitize_stdfds();

	git_setup_gettext();

	argv[0] = git_extract_argv0_path(argv[0]);

	restore_sigpipe_to_default();

	return cmd_main(argc, argv);
}