feat: shell and signal demo as loadable user executable

[lunaix-os.git] / lunaix-os / kernel / loader / elf.c

diff --git a/lunaix-os/kernel/loader/elf.c b/lunaix-os/kernel/loader/elf.c
index 7880fe60517d7a325178165afba3e1bce0adac0b..f6d494759591a2c6e42c124ff387e405e1cbc9a8 100644 (file)
--- a/lunaix-os/kernel/loader/elf.c
+++ b/lunaix-os/kernel/loader/elf.c
@@ -7,39 +7,13 @@
 #include <lunaix/mm/vmm.h>
 #include <lunaix/spike.h>
 
-int
-__elf_populate_mapped(struct mm_region* region, void* pg, off_t offset)
-{
-    struct elf32_phdr* phdr = (struct elf32_phdr*)region->data;
-    size_t segsz = phdr->p_filesz;
-    size_t segoff = offset - phdr->p_offset;
-
-    if (segoff >= segsz) {
-        return 0;
-    }
-
-    struct v_file* file = region->mfile;
-    size_t rdlen = MIN(segsz - segoff, PG_SIZE);
-
-    if (rdlen == PG_SIZE) {
-        // This is because we want to exploit any optimization on read_page
-        return file->ops->read_page(file->inode, pg, PG_SIZE, offset);
-    } else {
-        return file->ops->read(file->inode, pg, rdlen, offset);
-    }
-}
-
-void
-__elf_destruct_mapped(struct mm_region* region)
-{
-    vfree(region->data);
-}
-
 int
 elf_map_segment(struct ld_param* ldparam,
                 struct v_file* elfile,
                 struct elf32_phdr* phdr)
 {
+    assert(PG_ALIGNED(phdr->p_offset));
+
     int proct = 0;
     if ((phdr->p_flags & PF_R)) {
         proct |= PROT_READ;
@@ -51,24 +25,22 @@ elf_map_segment(struct ld_param* ldparam,
         proct |= PROT_EXEC;
     }
 
-    struct mm_region* seg_reg;
     struct mmap_param param = { .vms_mnt = ldparam->vms_mnt,
-                                .regions = &ldparam->proc->mm.regions,
+                                .pvms = &ldparam->proc->mm,
                                 .proct = proct,
-                                .offset = phdr->p_offset,
-                                .length = ROUNDUP(phdr->p_memsz, PG_SIZE),
-                                .flags =
-                                  MAP_FIXED | MAP_PRIVATE | REGION_TYPE_CODE };
+                                .offset = PG_ALIGN(phdr->p_offset),
+                                .mlen = ROUNDUP(phdr->p_memsz, PG_SIZE),
+                                .flen = phdr->p_filesz + PG_MOD(phdr->p_va),
+                                .flags = MAP_FIXED | MAP_PRIVATE,
+                                .type = REGION_TYPE_CODE };
 
+    struct mm_region* seg_reg;
     int status = mem_map(NULL, &seg_reg, PG_ALIGN(phdr->p_va), elfile, &param);
 
     if (!status) {
-        struct elf32_phdr* phdr_ = valloc(sizeof(SIZE_PHDR));
-        *phdr_ = *phdr;
-        seg_reg->data = phdr;
-
-        seg_reg->init_page = __elf_populate_mapped;
-        seg_reg->destruct_region = __elf_destruct_mapped;
+        size_t next_addr = phdr->p_memsz + phdr->p_va;
+        ldparam->info.end = MAX(ldparam->info.end, ROUNDUP(next_addr, PG_SIZE));
+        ldparam->info.mem_sz += phdr->p_memsz;
     }
 
     return status;
@@ -89,18 +61,34 @@ elf_setup_mapping(struct ld_param* ldparam,
     }
 
     tbl_sz = 1 << ILOG2(tbl_sz);
-    phdrs = elfile->ops->read(elfile->inode, phdrs, tbl_sz, ehdr->e_phoff);
+    status = elfile->ops->read(elfile->inode, phdrs, tbl_sz, ehdr->e_phoff);
+
+    if (status < 0) {
+        goto done;
+    }
+
+    if (PG_ALIGN(phdrs[0].p_va) != USER_START) {
+        status = ENOEXEC;
+        goto done;
+    }
 
     size_t entries = tbl_sz / SIZE_PHDR;
     for (size_t i = 0; i < entries; i++) {
         struct elf32_phdr* phdr = &phdrs[i];
 
         if (phdr->p_type == PT_LOAD) {
-            status = elf_map_segment(ldparam, elfile, phdr);
+            if (phdr->p_align == PG_SIZE) {
+                status = elf_map_segment(ldparam, elfile, phdr);
+            } else {
+                // surprising alignment!
+                status = ENOEXEC;
+            }
         }
         // TODO process other types of segments
 
         if (status) {
+            // errno in the middle of mapping restructuring, it is impossible
+            // to recover!
             ldparam->status |= LD_STAT_FKUP;
             goto done;
         }
@@ -117,7 +105,7 @@ elf_load(struct ld_param* ldparam, struct v_file* elfile)
     struct elf32_ehdr* ehdr = valloc(SIZE_EHDR);
     int status = elfile->ops->read(elfile->inode, ehdr, SIZE_EHDR, 0);
 
-    if (status) {
+    if (status < 0) {
         goto done;
     }
 
@@ -130,7 +118,7 @@ elf_load(struct ld_param* ldparam, struct v_file* elfile)
         goto done;
     }
 
-    ldparam->ehdr_out = *ehdr;
+    ldparam->info.ehdr_out = *ehdr;
 
 done:
     vfree(ehdr);