Init commit of jobs output/error message peek project.

src/worker/src/controller_connector.c

@@ -1,3 +1,4 @@
+#include "client.h"
 #include "controller_connector.h"
 #include "netio.h"
 #include "uv_ipc.h"
@@ -11,6 +12,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <sys/stat.h>
 
 #ifdef _WIN32
 #include <windows.h>
@@ -1097,6 +1099,89 @@ static int handle_runtasks(xce_request_t* request)
     return 0;
 }
 
+/**
+ * @brief Handles the fetchfile request from the controller.
+ *
+ * Reads up to msg->max_bytes bytes from msg->filepath starting at msg->offset
+ * and sends the data back to the controller as an OPCode_reply.
+ *
+ * @param request Pointer to the xce_request_t containing the fetchfile msg.
+ * @return int 0 on success, -1 on failure.
+ */
+static int handle_fetchfile(xce_request_t* request)
+{
+    xce_fetchfile_t*      msg = request->body.fetchfilemsg;
+    xce_fetchfile_reply_t freply;
+    struct stat           st;
+    uint8_t*              buf = NULL;
+    int                   fd;
+    ssize_t               nread;
+    uint32_t              maxbytes;
+
+    XCECD_LOG(XCE_LOG_DEBUG,
+              "Fetchfile request: jobid=%lu path=%s offset=%lu max=%u",
+              msg->jobid, msg->filepath, msg->offset, msg->max_bytes);
+
+    memset(&freply, 0, sizeof(freply));
+    freply.jobid = msg->jobid;
+
+    if (msg->filepath == NULL || msg->filepath[0] == '\0') {
+        XCECD_LOG(XCE_LOG_ERROR, "Fetchfile: empty filepath");
+        freply.error = -EINVAL;
+        goto send;
+    }
+
+    /* Bound max_bytes to avoid huge allocations */
+    maxbytes = (msg->max_bytes == 0 || msg->max_bytes > 4 * 1024 * 1024)
+                   ? 4 * 1024 * 1024
+                   : msg->max_bytes;
+
+    fd = open(msg->filepath, O_RDONLY);
+    if (fd < 0) {
+        XCECD_LOG(XCE_LOG_ERROR, "Fetchfile: open(%s) failed: %s",
+                  msg->filepath, strerror(errno));
+        freply.error = -errno;
+        goto send;
+    }
+
+    if (fstat(fd, &st) < 0) {
+        freply.error = -errno;
+        close(fd);
+        goto send;
+    }
+    freply.file_size = (uint64_t)st.st_size;
+
+    buf = malloc(maxbytes);
+    if (buf == NULL) {
+        freply.error = -ENOMEM;
+        close(fd);
+        goto send;
+    }
+
+    nread = pread(fd, buf, maxbytes, (off_t)msg->offset);
+    close(fd);
+
+    if (nread < 0) {
+        XCECD_LOG(XCE_LOG_ERROR, "Fetchfile: pread failed: %s",
+                  strerror(errno));
+        freply.error      = -errno;
+        freply.bytes_read = 0;
+        free(buf);
+        buf = NULL;
+    } else {
+        freply.error      = 0;
+        freply.bytes_read = (uint32_t)nread;
+        freply.content    = buf;
+        buf               = NULL; /* ownership passed to freply */
+    }
+
+send:
+    xcecli_reply_fetchfile(xcecli_ctx, request, &freply);
+    free(freply.content);
+    free(buf);
+    return 0;
+}
+
 /**
  * @brief Handles the runtasks request from the controller.
  *
@@ -1234,6 +1319,9 @@ static int myreq_handler(xce_request_t* request, void* args)
     case OPCode_jobcontrol:
         ret = handle_jobcontrol(request);
         break;
+    case OPCode_fetchfile:
+        ret = handle_fetchfile(request);
+        break;
     default:
         break;
     }