multiboot: set bootloader cmdline

README.md

@@ -17,6 +17,7 @@ bhyveload -h <hostbase> -m <memsize> -l /path/to/multiboot.so [[-e <key>=<value>
 
 With the following environment variables specified with -e:
 
-| name     | optional | description                                                                     |
-|----------|----------|---------------------------------------------------------------------------------|
-| `kernel` | no       | Path to the kernel image relative to `hostbase`. Must start with a leading `/`. |
+| name      | optional | description                                                                     |
+|-----------|----------|---------------------------------------------------------------------------------|
+| `kernel`  | no       | Path to the kernel image relative to `hostbase`. Must start with a leading `/`. |
+| `cmdline` | yes      | command line to pass to the kernel                                              |

loader.c

@@ -18,7 +18,8 @@ size_t highmem = 0;
 jmp_buf jb;
 
 struct args loader_args = {
-    .kernel_filename = NULL
+    .kernel_filename = NULL,
+    .cmdline = NULL,
 };
 
 uint32_t
@@ -47,6 +48,10 @@ parse_args(struct args* args)
 
             args->kernel_filename = value;
         }
+
+        if (!strncmp(var, "cmdline", delim-var)) {
+            args->cmdline = value;
+        }
     }
 
     return 0;
@@ -124,6 +129,13 @@ loader_main(struct loader_callbacks *cb, void *arg, int version, int ndisks)
         if (multiboot_load(kernel, kernsz, mb)) {
             goto error;
         }
+
+        if (loader_args.cmdline &&
+            multiboot_info_set_cmdline(&mb->info, loader_args.cmdline))
+        {
+            ERROR(EINVAL, "Could not set kernel command line");
+            goto error;
+        }
     }
 
     /* Cleanup. */

loader.h

@@ -51,6 +51,7 @@ extern jmp_buf jb;
 
 struct args {
     const char* kernel_filename;
+	const char* cmdline;
 };
 
 extern struct loader_args args;

multiboot.c

@@ -27,6 +27,7 @@
 
 #include <stdio.h>
 #include <stdlib.h>
+#include <string.h>
 #include <errno.h>
 
 #include <sys/types.h>
@@ -41,6 +42,22 @@
 
 void *entry = NULL;
 
+uint32_t
+multiboot_info_set_cmdline(struct multiboot_info* info, const char* cmdline)
+{
+    uint32_t error = 0;
+    size_t length = strlen(cmdline);
+    void* p_addr = allocate(length+1);
+
+    if (!p_addr)
+        return ENOMEM;
+
+    error = CALLBACK(copyin, cmdline, p_addr, length+1);
+    info->cmdline = p_addr;
+    info->flags |= MULTIBOOT_CMDLINE;
+    return error;
+}
+
 struct multiboot*
 mb_scan(void *kernel, size_t kernsz)
 {

multiboot.h

@@ -221,4 +221,13 @@ multiboot_load_elf(void *kernel, size_t kernsz, Elf *kernel_elf);
 uint32_t
 multiboot_load(void* kernel, size_t kernsz, struct multiboot *mb);
 
+/**
+ * @brief Set multiboot info command line
+ *
+ * @param info pointer to the multiboot_info struct
+ * @param cmdline command line to set
+ * @return uint32_t 0 on success, error code on failure
+ */
+uint32_t
+multiboot_info_set_cmdline(struct multiboot_info* info, const char* cmdline);
 /* vim: set noexpandtab ts=4 : */