Add injector

loader/src/common/socket_utils.cpp

@@ -0,0 +1,114 @@
+#include <cstddef>
+#include <sys/socket.h>
+#include <unistd.h>
+
+#include "socket_utils.h"
+
+namespace socket_utils {
+
+    ssize_t xread(int fd, void* buf, size_t count) {
+        size_t read_sz = 0;
+        ssize_t ret;
+        do {
+            ret = read(fd, (std::byte*) buf + read_sz, count - read_sz);
+            if (ret < 0) {
+                if (errno == EINTR) continue;
+                PLOGE("read");
+                return ret;
+            }
+            read_sz += ret;
+        } while (read_sz != count && ret != 0);
+        if (read_sz != count) {
+            PLOGE("read (%d != %d)", count, read_sz);
+        }
+        return read_sz;
+    }
+
+    ssize_t xwrite(int fd, const void* buf, size_t count) {
+        size_t write_sz = 0;
+        ssize_t ret;
+        do {
+            ret = write(fd, (std::byte*) buf + write_sz, count - write_sz);
+            if (ret < 0) {
+                if (errno == EINTR) continue;
+                PLOGE("write");
+                return ret;
+            }
+            write_sz += ret;
+        } while (write_sz != count && ret != 0);
+        if (write_sz != count) {
+            PLOGE("write (%d != %d)", count, write_sz);
+        }
+        return write_sz;
+    }
+
+    ssize_t xrecvmsg(int sockfd, struct msghdr* msg, int flags) {
+        int rec = recvmsg(sockfd, msg, flags);
+        if (rec < 0) PLOGE("recvmsg");
+        return rec;
+    }
+
+    void* recv_fds(int sockfd, char* cmsgbuf, size_t bufsz, int cnt) {
+        iovec iov = {
+                .iov_base = &cnt,
+                .iov_len  = sizeof(cnt),
+        };
+        msghdr msg = {
+                .msg_iov        = &iov,
+                .msg_iovlen     = 1,
+                .msg_control    = cmsgbuf,
+                .msg_controllen = bufsz
+        };
+
+        xrecvmsg(sockfd, &msg, MSG_WAITALL);
+        cmsghdr* cmsg = CMSG_FIRSTHDR(&msg);
+
+        if (msg.msg_controllen != bufsz ||
+            cmsg == nullptr ||
+            cmsg->cmsg_len != CMSG_LEN(sizeof(int) * cnt) ||
+            cmsg->cmsg_level != SOL_SOCKET ||
+            cmsg->cmsg_type != SCM_RIGHTS) {
+            return nullptr;
+        }
+
+        return CMSG_DATA(cmsg);
+    }
+
+    template<typename T>
+    inline T read_exact(int fd) {
+        T res;
+        return sizeof(T) == xread(fd, &res, sizeof(T)) ? res : -1;
+    }
+
+    template<typename T>
+    inline bool write_exact(int fd, T val) {
+        return sizeof(T) == xwrite(fd, &val, sizeof(T));
+    }
+
+    size_t read_usize(int fd) {
+        return read_exact<size_t>(fd);
+    }
+
+    std::string read_string(int fd) {
+        auto len = read_exact<size_t>(fd);
+        char buf[len + 1];
+        buf[len] = '\0';
+        xread(fd, buf, len);
+        return buf;
+    }
+
+    bool write_u8(int fd, uint8_t val) {
+        return write_exact<uint8_t>(fd, val);
+    }
+
+    int recv_fd(int sockfd) {
+        char cmsgbuf[CMSG_SPACE(sizeof(int))];
+
+        void* data = recv_fds(sockfd, cmsgbuf, sizeof(cmsgbuf), 1);
+        if (data == nullptr) return -1;
+
+        int result;
+        memcpy(&result, data, sizeof(int));
+        return result;
+    }
+}