Fixed cat command causing an unknown exception. Added more proc functions.

Author: pradosh-arduino

source/kernel/C/filesystems/layers/proc.c

@@ -12,6 +12,7 @@
 #include <basics.h>
 #include <strings.h>
 #include <heap.h>
+#include <memory.h>
 
 #define PROCFS_MAX_FILES 32
 
@@ -86,6 +87,59 @@ static procfs_entry_t proc_heap = {
     .priv  = NULL
 };
 
+extern struct memory_context* limine_memory_ctx;
+
+static int proc_meminfo_read(vfs_file_t* file, uint8_t* buf, uint32_t size, void* priv) {
+    (void)priv;
+
+    char tmp[512];
+    int len = 0;
+
+    // Convert bytes to KB
+    uint64_t kb_total       = limine_memory_ctx->total / 1024;
+    uint64_t kb_free        = limine_memory_ctx->usable / 1024;
+    uint64_t kb_reserved    = limine_memory_ctx->reserved / 1024;
+    uint64_t kb_acpi_reclaim= limine_memory_ctx->acpi_reclaimable / 1024;
+    uint64_t kb_acpi_nvs    = limine_memory_ctx->acpi_nvs / 1024;
+    uint64_t kb_bad         = limine_memory_ctx->bad / 1024;
+    uint64_t kb_boot        = limine_memory_ctx->bootloader_reclaimable / 1024;
+    uint64_t kb_kernel      = limine_memory_ctx->kernel_modules / 1024;
+    uint64_t kb_fb          = limine_memory_ctx->framebuffer / 1024;
+    uint64_t kb_unknown     = limine_memory_ctx->unknown / 1024;
+
+    // Build meminfo string like Linux
+    len += snprintf(tmp + len, sizeof(tmp) - len,
+        "MemTotal:       %u kB\n"
+        "MemFree:        %u kB\n"
+        "MemReserved:    %u kB\n"
+        "ACPI Reclaim:   %u kB\n"
+        "ACPI NVS:       %u kB\n"
+        "BadMem:         %u kB\n"
+        "Bootloader:     %u kB\n"
+        "KernelModules:  %u kB\n"
+        "Framebuffer:    %u kB\n"
+        "Unknown:        %u kB\n",
+        kb_total, kb_free, kb_reserved, kb_acpi_reclaim,
+        kb_acpi_nvs, kb_bad, kb_boot, kb_kernel, kb_fb, kb_unknown
+    );
+
+    // Handle file offset for multiple reads
+    if (file->pos >= (uint32_t)len) return 0;
+
+    uint32_t rem = len - file->pos;
+    if (rem > size) rem = size;
+
+    memcpy(buf, tmp + file->pos, rem);
+    file->pos += rem;
+    return rem;
+}
+
+static procfs_entry_t proc_meminfo = {
+    .name  = "meminfo",
+    .read  = proc_meminfo_read,
+    .write = NULL,
+    .priv  = NULL
+};
 
 /* END */
 
@@ -94,6 +148,7 @@ void procfs_init(void) {
     memset(proc_files, 0, sizeof(proc_files));
     procfs_register(&proc_stat);
     procfs_register(&proc_heap);
+    procfs_register(&proc_meminfo);
 }
 
 /* Register a virtual proc file */
@@ -115,30 +170,40 @@ static procfs_entry_t* procfs_find(const char* name) {
 }
 
 int procfs_open(vfs_file_t* file) {
+    if (!file || !file->rel_path)
+        return -1;
+
     procfs_entry_t* e = procfs_find(file->rel_path);
     if (!e)
-        return -1;
+        return -1; // file doesn't exist
 
     file->pos = 0;
     return 0;
 }
 
 int procfs_read(vfs_file_t* file, uint8_t* buf, uint32_t size) {
+    if (!file || !file->rel_path || !buf)
+        return -1;
+
     procfs_entry_t* e = procfs_find(file->rel_path);
-    if (!e || !e->read)
-        return 0;
+    if (!e) return -1;        // file not found
+    if (!e->read) return -1;  // read not supported
 
     return e->read(file, buf, size, e->priv);
 }
 
 int procfs_write(vfs_file_t* file, const uint8_t* buf, uint32_t size) {
-    procfs_entry_t* e = procfs_find(file->rel_path);
-    if (!e || !e->write)
+    if (!file || !file->rel_path || !buf)
         return -1;
 
+    procfs_entry_t* e = procfs_find(file->rel_path);
+    if (!e) return -1;
+    if (!e->write) return -1;
+
     return e->write(file, buf, size, e->priv);
 }
 
+
 void procfs_close(vfs_file_t* file) {
     (void)file;
 }

source/kernel/C/filesystems/vfs.c

@@ -246,7 +246,11 @@ int vfs_open(const char* path, int flags, vfs_file_t* out)
         strncpy(out->rel_path, res.rel_path, sizeof(out->rel_path));
         out->mnt = res.mnt;
         out->flags = flags;
-        return procfs_open(out);
+        
+        if (procfs_open(out) != 0)  // if file not found
+            return -1;
+        
+        return 0;
     }
 
     if (res.mnt->type == FS_FAT16) {

source/kernel/C/kernel.c

@@ -50,6 +50,7 @@ struct limine_module_request module_request = {
 
 struct flanterm_context *ft_ctx = null;
 struct limine_framebuffer *framebuffer = null;
+struct memory_context* limine_memory_ctx;
 
 bool isBufferReady = no;
 
@@ -159,7 +160,7 @@ void main(void) {
     // void* heap_page = allocate_pages(64 MiB / PAGE_SIZE);
     // mm_init(heap_page, 64 MiB);
 
-    struct memory_context* memory = (struct memory_context*)kmalloc(sizeof(struct memory_context));
+    limine_memory_ctx = (struct memory_context*)kmalloc(sizeof(struct memory_context));
 
     acpi_init();
 
@@ -170,7 +171,7 @@ void main(void) {
 
     RTL8139 = (struct rtl8139*) kmalloc(sizeof(struct rtl8139));
 
-    analyze_memory_map(memory, memory_map_request);
+    analyze_memory_map(limine_memory_ctx, memory_map_request);
 
     uintptr_t page1 = allocate_page();
     uintptr_t page2 = allocate_page();
@@ -196,10 +197,10 @@ void main(void) {
     printf("Display Resolution: %dx%d (%d) pixels. Pitch: %d", framebuffer->width, framebuffer->height, framebuffer->width*framebuffer->height, framebuffer->pitch);
 
     info("Memory Values begin! ===", __FILE__);
-    display_memory_formatted(memory);
+    display_memory_formatted(limine_memory_ctx);
     info(reset_color "Memory values end! =====", __FILE__);
 
-    if(memory->bad != 0){
+    if(limine_memory_ctx->bad != 0){
         warn("Bad blocks of memory found, it is recommended to replace your RAM.", __FILE__);
     }
 

source/kernel/C/shell/commands/cat.c

@@ -49,12 +49,12 @@ int cmd_cat(int argc, char** argv)
                 printfnoln("%c", buf[j]);
         }
 
+        if(j != 0)
+            if(buf[j-1] != '\n')
+                print("\n");
+
         vfs_close(&file);
     }
-
-    if(j != 0)
-        if(buf[j-1] != '\n')
-            print("\n");
 
     return 0;
 }