shell: Add vfs command

usage: vfs r /path/to/file nbytes offset

Only reading is currently supported

Author: Joakim Nohlgård

sys/shell/commands/Makefile

@@ -69,6 +69,9 @@ endif
 ifneq (,$(filter ccn-lite-utils,$(USEMODULE)))
   SRC += sc_ccnl.c
 endif
+ifneq (,$(filter vfs,$(USEMODULE)))
+  SRC += sc_vfs.c
+endif
 
 # TODO
 # Conditional building not possible at the moment due to

sys/shell/commands/sc_vfs.c

@@ -0,0 +1,166 @@
+/*
+ * Copyright (C) 2016 Eistec AB
+ *
+ * This file is subject to the terms and conditions of the GNU Lesser
+ * General Public License v2.1. See the file LICENSE in the top level
+ * directory for more details.
+ */
+
+/**
+ * @ingroup     sys_shell_commands
+ * @{
+ *
+ * @file
+ * @brief       Shell commands for the VFS module
+ *
+ * @author      Joakim Nohlgård <joakim.nohlgard@eistec.se>
+ *
+ * @}
+ */
+
+#ifdef BOARD_MULLE
+#include <stdint.h>
+#include <inttypes.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <ctype.h>
+#include <errno.h>
+#include <unistd.h>
+#include <fcntl.h>
+
+#include "vfs.h"
+
+static void _usage(char **argv)
+{
+    printf("%s <r|w> <path> [bytes] [offset]\n", argv[0]);
+    puts("r: Read [bytes] bytes at [offset] in file <path>");
+}
+
+/* Macro used by _errno_string to expand errno labels to string and print it */
+#define _case_snprintf_errno_name(x) \
+    case x: \
+        res = snprintf(buf, buflen, #x); \
+        break
+
+static int _errno_string(int err, char *buf, size_t buflen)
+{
+    int len = 0;
+    int res;
+    if (err < 0) {
+        res = snprintf(buf, buflen, "-");
+        if (res < 0) {
+            return res;
+        }
+        if (res <= buflen) {
+            buf += res;
+            buflen -= res;
+        }
+        len += res;
+        err = -err;
+    }
+    switch (err) {
+        _case_snprintf_errno_name(EACCES);
+        _case_snprintf_errno_name(ENOENT);
+        _case_snprintf_errno_name(EINVAL);
+        _case_snprintf_errno_name(EFAULT);
+        _case_snprintf_errno_name(EROFS);
+        _case_snprintf_errno_name(EIO);
+
+        default:
+            res = snprintf(buf, buflen, "%d", err);
+            break;
+    }
+    if (res < 0) {
+        return res;
+    }
+    len += res;
+    return len;
+}
+#undef _case_snprintf_errno_name
+
+int _vfs_handler(int argc, char **argv)
+{
+    printf("vfs: %d, %p\n", argc, (void *)argv);
+    if (argc < 3) {
+        _usage(argv);
+        return 1;
+    }
+    if (strcmp(argv[1], "r") != 0) {
+        printf("Only read is currently supported");
+        return 2;
+    }
+    uint8_t buf[16];
+    size_t nbytes = sizeof(buf);
+    off_t offset = 0;
+    char *path = argv[2];
+    if (argc > 3) {
+        nbytes = atoi(argv[3]);
+    }
+    if (argc > 4) {
+        offset = atoi(argv[4]);
+    }
+
+    vfs_normalize_path(path, path, strlen(path));
+
+    int fd = vfs_open(path, O_RDONLY, 0);
+    if (fd < 0) {
+        _errno_string(fd, (char *)buf, sizeof(buf));
+        printf("Error opening file \"%s\": %s\n", path, buf);
+        return 3;
+    }
+
+    int res;
+    res = vfs_lseek(fd, offset, SEEK_SET);
+    if (res < 0) {
+        _errno_string(fd, (char *)buf, sizeof(buf));
+        printf("Seek error: %s\n", buf);
+        vfs_close(fd);
+        return 4;
+    }
+
+    while (nbytes > 0) {
+        size_t line_len = (nbytes < sizeof(buf) ? nbytes : sizeof(buf));
+        res = vfs_read(fd, buf, line_len);
+        if (res < 0) {
+            _errno_string(fd, (char *)buf, sizeof(buf));
+            printf("Read error: %s\n", buf);
+            vfs_close(fd);
+            return 5;
+        }
+        else if (res > line_len) {
+            printf("BUFFER OVERRUN! %d > %lu\n", res, (unsigned long)line_len);
+            vfs_close(fd);
+            return 6;
+        }
+        else if (res == 0) {
+            /* EOF */
+            printf("-- EOF --\n");
+            break;
+        }
+        printf("%08lx:", (unsigned long)offset);
+        for (size_t k = 0; k < res; ++k) {
+            if ((k % 2) == 0) {
+                putchar(' ');
+            }
+            printf("%02x", buf[k]);
+        }
+        putchar(' ');
+        putchar(' ');
+        for (size_t k = 0; k < res; ++k) {
+            if (isprint(buf[k])) {
+                putchar(buf[k]);
+            }
+            else {
+                putchar('.');
+            }
+        }
+        puts("");
+        offset += res;
+        nbytes -= res;
+    }
+
+    vfs_close(fd);
+    return 0;
+}
+#endif

sys/shell/commands/shell_commands.c

@@ -129,6 +129,10 @@ extern int _ccnl_interest(int argc, char **argv);
 extern int _ccnl_fib(int argc, char **argv);
 #endif
 
+#ifdef MODULE_VFS
+extern int _vfs_handler(int argc, char **argv);
+#endif
+
 const shell_command_t _shell_command_list[] = {
     {"reboot", "Reboot the node", _reboot_handler},
 #ifdef MODULE_CONFIG
@@ -209,10 +213,13 @@ const shell_command_t _shell_command_list[] = {
     {"saul", "interact with sensors and actuators using SAUL", _saul },
 #endif
 #ifdef MODULE_CCN_LITE_UTILS
-    { "ccnl_open", "opens an interface or socket", _ccnl_open},
-    { "ccnl_int", "sends an interest", _ccnl_interest},
-    { "ccnl_cont", "create content and populated it", _ccnl_content},
-    { "ccnl_fib", "shows or modifies the CCN-Lite FIB", _ccnl_fib},
+    {"ccnl_open", "opens an interface or socket", _ccnl_open},
+    {"ccnl_int", "sends an interest", _ccnl_interest},
+    {"ccnl_cont", "create content and populated it", _ccnl_content},
+    {"ccnl_fib", "shows or modifies the CCN-Lite FIB", _ccnl_fib},
+#endif
+#ifdef MODULE_VFS
+    {"vfs", "read files", _vfs_handler},
 #endif
     {NULL, NULL, NULL}
 };