Minor code improvements and split into multiple c files

Signed-off-by: Mattias Andrée <m@maandree.se>

1 files changed, 119 insertions, 0 deletions

diff --git a/libcoopgamma_query__.c b/libcoopgamma_query__.c
new file mode 100644
index 0000000..706a3cf
--- /dev/null
+++ b/libcoopgamma_query__.c
@@ -0,0 +1,119 @@
+/* See LICENSE file for copyright and license details. */
+#include "common.h"
+
+
+/**
+ * Run coopgammad with -q or -qq and return the response
+ * 
+ * SIGCHLD must not be ignored or blocked
+ * 
+ * @param   method   The adjustment method, `NULL` for automatic
+ * @param   site     The site, `NULL` for automatic
+ * @param   arg      "-q" or "-qq", which shall be passed to coopgammad?
+ * @return           The output of coopgammad, `NULL` on error. This
+ *                   will be NUL-terminated and will not contain any
+ *                   other `NUL` bytes.
+ */
+char *
+libcoopgamma_query__(const char *restrict method, const char *restrict site, const char *restrict arg)
+{
+	const char *(args[7]) = {COOPGAMMAD, arg};
+	size_t i = 2, n = 0, size = 0;
+	int pipe_rw[2] = { -1, -1 };
+	pid_t pid;
+	int saved_errno, status;
+	char *msg = NULL;
+	ssize_t got;
+	void *new;
+
+	if (method) args[i++] = "-m", args[i++] = method;
+	if (site)   args[i++] = "-s", args[i++] = site;
+	args[i] = NULL;
+
+	if (pipe(pipe_rw) < 0)
+		goto fail;
+
+	switch ((pid = fork())) {
+	case -1:
+		goto fail;
+
+	case 0:
+		/* Child */
+		close(pipe_rw[0]);
+		if (pipe_rw[1] != STDOUT_FILENO) {
+			close(STDOUT_FILENO);
+			if (dup2(pipe_rw[1], STDOUT_FILENO) < 0)
+				goto fail_child;
+			close(pipe_rw[1]);
+		}
+#if defined(__GNUC__)
+# pragma GCC diagnostic push
+# pragma GCC diagnostic ignored "-Wcast-qual"
+#endif
+		execvp(COOPGAMMAD, (char* const*)(args));
+#if defined(__GNUC__)
+# pragma GCC diagnostic pop
+#endif
+	fail_child:
+		saved_errno = errno;
+		perror(NAME_OF_THE_PROCESS);
+		if (write(STDOUT_FILENO, &saved_errno, sizeof(int)) != sizeof(int))
+			perror(NAME_OF_THE_PROCESS);
+		exit(1);
+
+	default:
+		/* Parent */
+		close(pipe_rw[1]), pipe_rw[1] = -1;
+		for (;;) {
+			if (n == size) {
+				new = realloc(msg, size = (n ? (n << 1) : 256U));
+				if (!new)
+					goto fail;
+				msg = new;
+			}
+			got = read(pipe_rw[0], &msg[n], size - n);
+			if (got < 0) {
+				if (errno == EINTR)
+					continue;
+				goto fail;
+			} else if (got == 0) {
+				break;
+			}
+			n += (size_t)got;
+		}
+		close(pipe_rw[0]), pipe_rw[0] = -1;
+		if (waitpid(pid, &status, 0) < 0)
+			goto fail;
+		if (status) {
+			errno = EINVAL;
+			if (n == sizeof(int) && *(int *)msg)
+				errno = *(int*)msg;
+		}
+		break;
+	}
+
+	if (n == size) {
+		new = realloc(msg, n + 1U);
+		if (!new)
+			goto fail;
+		msg = new;
+	}
+	msg[n] = '\0';
+
+	if (strchr(msg, '\0') != msg + n) {
+		errno = EBADMSG;
+		goto fail;
+	}
+
+	return msg;
+
+fail:
+	saved_errno = errno;
+	if (pipe_rw[0] >= 0)
+		close(pipe_rw[0]);
+	if (pipe_rw[1] >= 0)
+		close(pipe_rw[1]);
+	free(msg);
+	errno = saved_errno;
+	return NULL;
+}