[srv.init] Iterate and load drivers and services from initrd

Previously we were hard-coding loading specific files (the UART driver
and logging server) from the initrd. Now j6romfs has a for_each() method
to allow iterating all files in a directory, and init loads all programs
from /jsix/drivers and /jsix/services. Eventually this will need more
dynamic loading decisions for drivers but for now it's fine.

src/user/srv.init/j6romfs.cpp

@@ -1,7 +1,9 @@
 #include <assert.h>
 #include <string.h>
 #include <util/hash.h>
+
 #include <zstd.h>
+#include <zstd_errors.h>
 
 #include "j6romfs.h"
 
@@ -37,31 +39,13 @@ fs::fs(util::const_buffer data) :
 util::const_buffer
 fs::load_simple(char const *path) const
 {
-    if (!path)
+    const inode *in = lookup_inode(path);
+    if (!in || in->type != inode_type::file)
         return {0, 0};
 
-    char element [buf_size];
-    inode const *in = m_root;
-
-    while (*path) {
-        path = copy_path_element(path, element);
-        in = lookup_inode_in_dir(in, element);
-
-        if (!in) {
-            // entry was not found
-            break;
-        } else if (*path && in->type == inode_type::file) {
-            // a directory was expected
-            break;
-        } else if (in->type == inode_type::file) {
-            // load the file
-            uint8_t *data = new uint8_t [in->size];
-            size_t total = load_inode_data(in, util::buffer::from(data, in->size));
-            return util::buffer::from(data, total);
-        }
-    }
-
-    return {0, 0};
+    uint8_t *data = new uint8_t [in->size];
+    size_t total = load_inode_data(in, util::buffer::from(data, in->size));
+    return util::buffer::from(data, total);
 }
 
 size_t
@@ -80,10 +64,43 @@ fs::load_inode_data(const inode *in, util::buffer dest) const
 
     size_t decom = ZSTD_decompress(dest.pointer, dest.count,
             src.pointer, in->compressed);
-    assert(!ZSTD_isError(decom) && "Error decompressing");
+    if (ZSTD_isError(decom)) {
+        ZSTD_ErrorCode err = ZSTD_getErrorCode(decom);
+        const char *name = ZSTD_getErrorString(err);
+        assert(!name);
+    }
+
     return decom;
 }
 
+const inode *
+fs::lookup_inode(const char *path) const
+{
+    if (!path)
+        return nullptr;
+
+    char element [buf_size];
+    inode const *in = m_root;
+
+    while (*path) {
+        path = copy_path_element(path, element);
+        in = lookup_inode_in_dir(in, element);
+
+        if (!in) {
+            // entry was not found
+            break;
+        } else if (!*path) {
+            // found it
+            return in;
+        } else if (*path && in->type == inode_type::file) {
+            // a directory was expected
+            break;
+        }
+    }
+
+    return nullptr;
+}
+
 const inode *
 fs::lookup_inode_in_dir(const inode *dir, const char *name) const
 {

src/user/srv.init/j6romfs.h

@@ -50,9 +50,36 @@ public:
     fs(util::const_buffer data);
 
     util::const_buffer load_simple(char const *path) const;
+    size_t load_inode_data(const inode *in, util::buffer dest) const;
+
+    template <typename callback>
+    size_t for_each(const char *root, callback &&cb) const
+    {
+        const inode *in = lookup_inode(root);
+        if (!in || in->type != inode_type::directory)
+            return 0;
+
+        uint8_t *dir_data = new uint8_t [in->size];
+        load_inode_data(in, util::buffer::from(dir_data, in->size));
+        const dirent *entries = reinterpret_cast<const dirent*>(dir_data);
+
+        size_t i = 0, max = in->size / sizeof(dirent);
+        for (; i < max; ++i) {
+            const dirent &e = entries[i];
+            const char *name = reinterpret_cast<const char*>(dir_data + e.name_offset);
+
+            cb(&m_inodes[e.inode], name);
+
+            size_t new_max = e.name_offset / sizeof(dirent);
+            if (new_max < max) max = new_max;
+        }
+
+        delete [] dir_data;
+        return i;
+    }
 
 private:
-    size_t load_inode_data(const inode *in, util::buffer dest) const;
+    const inode * lookup_inode(const char *path) const;
     const inode * lookup_inode_in_dir(const inode *in, const char *name) const;
 
     util::const_buffer m_data;

src/user/srv.init/loader.cpp

@@ -141,7 +141,6 @@ load_program(
         return false;
     }
 
-    delete [] reinterpret_cast<const uint8_t*>(data.pointer);
     return true;
 }
 

src/user/srv.init/main.cpp

@@ -25,24 +25,6 @@ uintptr_t _arg_modules_phys;   // This gets filled in in _start
 
 extern j6_handle_t __handle_self;
 
-util::const_buffer
-load_driver_for(const char *name, const j6romfs::fs &initrd)
-{
-    char driver[256];
-    snprintf(driver, sizeof(driver), "/jsix/drivers/drv.%s.elf", name);
-
-    return initrd.load_simple(driver);
-}
-
-util::const_buffer
-load_service(const char *name, const j6romfs::fs &initrd)
-{
-    char service[256];
-    snprintf(service, sizeof(service), "/jsix/services/srv.%s.elf", name);
-
-    return initrd.load_simple(service);
-}
-
 int
 main(int argc, const char **argv)
 {
@@ -113,23 +95,45 @@ main(int argc, const char **argv)
     // have driver_source objects..
     j6romfs::fs initrd {initrd_module->data};
 
-    char err_msg [128];
+    char message[256];
 
-    util::const_buffer uart_elf = load_driver_for("uart", initrd);
-    if (uart_elf.pointer) {
-        if (!load_program("UART driver", uart_elf, sys_child, slp_mb_child, err_msg)) {
-            j6_log(err_msg);
-            return 1;
-        }
-    }
+    initrd.for_each("/jsix/drivers",
+            [=, &message](const j6romfs::inode *in, const char *name) {
+        if (in->type != j6romfs::inode_type::file)
+            return;
 
-    util::const_buffer logger_elf = load_service("logger", initrd);
-    if (uart_elf.pointer) {
-        if (!load_program("logger service", logger_elf, sys_child, slp_mb_child, err_msg)) {
-            j6_log(err_msg);
-            return 1;
+        sprintf(message, "Loading driver: %s", name);
+        j6_log(message);
+
+        uint8_t *data = new uint8_t [in->size];
+        util::buffer program {data, in->size};
+
+        initrd.load_inode_data(in, program);
+        if (!load_program(name, program, sys_child, slp_mb_child, message)) {
+            j6_log(message);
         }
-    }
+
+        delete [] data;
+    });
+
+    initrd.for_each("/jsix/services",
+            [=, &message](const j6romfs::inode *in, const char *name) {
+        if (in->type != j6romfs::inode_type::file)
+            return;
+
+        sprintf(message, "Loading service: %s", name);
+        j6_log(message);
+
+        uint8_t *data = new uint8_t [in->size];
+        util::buffer program {data, in->size};
+
+        initrd.load_inode_data(in, program);
+        if (!load_program(name, program, sys_child, slp_mb_child, message)) {
+            j6_log(message);
+        }
+
+        delete [] data;
+    });
 
     service_locator_start(slp_mb);
     return 0;