Add a simple unix controller

Signed-off-by: Adrien Gallouët <adrien@gallouet.fr>

src/ctl.c

@@ -0,0 +1,79 @@
+#include "common.h"
+
+#include "ctl.h"
+#include "str.h"
+
+#include <stdio.h>
+#include <sys/socket.h>
+#include <sys/stat.h>
+#include <sys/un.h>
+
+int
+ctl_init(const char *dir, const char *file)
+{
+    if (str_empty(dir) || str_empty(file)) {
+        errno = EINVAL;
+        return -1;
+    }
+
+    if (mkdir(dir, 0700) == -1 && errno != EEXIST) {
+        perror("mkdir");
+        return -1;
+    }
+
+    const char *strs[] = {dir, "/", file};
+    char *path = str_cat(strs, 3);
+
+    if (!path)
+        return -1;
+
+    int fd = socket(AF_UNIX, SOCK_DGRAM, 0);
+
+    if (fd == -1) {
+        int err = errno;
+        free(path);
+        errno = err;
+        return -1;
+    }
+
+    struct sockaddr_un sun = {
+        .sun_family = AF_UNIX,
+    };
+
+    str_cpy(sun.sun_path, path, sizeof(sun.sun_path) - 1);
+    free(path);
+    unlink(sun.sun_path);
+
+    if (bind(fd, (struct sockaddr *)&sun, sizeof(sun)) == -1) {
+        int err = errno;
+        close(fd);
+        errno = err;
+        return -1;
+    }
+
+    return fd;
+}
+
+int
+ctl_connect(int fd, const char *dir, const char *file)
+{
+    if (fd < 0 || str_empty(dir) || str_empty(file)) {
+        errno = EINVAL;
+        return -1;
+    }
+
+    const char *strs[] = {dir, "/", file};
+    char *path = str_cat(strs, 3);
+
+    if (!path)
+        return -1;
+
+    struct sockaddr_un sun = {
+        .sun_family = AF_UNIX,
+    };
+
+    str_cpy(sun.sun_path, path, sizeof(sun.sun_path) - 1);
+    free(path);
+
+    return connect(fd, (struct sockaddr *)&sun, sizeof(sun));
+}