Debug code to see remote kmsgs
[akaros.git] / kern / src / elf.c
index 1df6994..6cf23b1 100644 (file)
 #include <mm.h>
-#include <ros/mman.h>
+#include <frontend.h>
+#include <string.h>
 #include <kmalloc.h>
 #include <syscall.h>
 #include <elf.h>
 #include <pmap.h>
-
-struct elf_info
-{
-       long entry;
-       long phdr;
-       int phnum;
-       int dynamic;
-       char interp[256];
-};
-
-int load_one_elf(struct proc* p, int fd, int pgoffset, struct elf_info* ei)
+#include <smp.h>
+#include <arch/arch.h>
+
+#ifdef KERN64
+# define elf_field(obj, field) (elf64 ? (obj##64)->field : (obj##32)->field)
+#else
+# define elf_field(obj, field) ((obj##32)->field)
+#endif
+
+/* We need the writable flag for ld.  Even though the elf header says it wants
+ * RX (and not W) for its main program header, it will page fault (eip 56f0,
+ * 46f0 after being relocated to 0x1000, va 0x20f4). */
+static int load_one_elf(struct proc *p, struct file *f, uintptr_t pgoffset,
+                        elf_info_t *ei, bool writable)
 {
        int ret = -1;
        ei->phdr = -1;
        ei->dynamic = 0;
-
-       char* elf = (char*)kmalloc(PGSIZE,0);
-       if(!elf || read_page(p,fd,PADDR(elf),0) == -1)
+       ei->highest_addr = 0;
+       off_t f_off = 0;
+       void* phdrs = 0;
+       int mm_perms, mm_flags = MAP_FIXED;
+       
+       /* When reading on behalf of the kernel, we need to make sure no proc is
+        * "current".  This is a bit ghetto (TODO: KFOP) */
+       struct proc *cur_proc = current;
+       current = 0;
+
+       /* Read in ELF header. */
+       elf64_t elfhdr_storage;
+       elf32_t* elfhdr32 = (elf32_t*)&elfhdr_storage;
+       elf64_t* elfhdr64 = &elfhdr_storage;
+       if (f->f_op->read(f, (char*)elfhdr64, sizeof(elf64_t), &f_off) == -1)
                goto fail;
 
-       elf_t* elfhdr = (elf_t*)elf;
-       proghdr_t* proghdrs = (proghdr_t*)(elf+elfhdr->e_phoff);
-       if(elfhdr->e_phoff+elfhdr->e_phnum*sizeof(proghdr_t) > PGSIZE)
+       bool elf32 = elfhdr32->e_ident[ELF_IDENT_CLASS] == ELFCLASS32;
+       bool elf64 = elfhdr64->e_ident[ELF_IDENT_CLASS] == ELFCLASS64;
+       if (elf64 == elf32)
                goto fail;
-       if(elfhdr->e_phentsize != sizeof(proghdr_t))
+       #ifndef KERN64
+       if(elf64)
                goto fail;
-
-       for(int i = 0; i < elfhdr->e_phnum; i++)
-       {
-               proghdr_t* ph = proghdrs+i;
-               if(ph->p_type == ELF_PROG_PHDR)
-                       ei->phdr = ph->p_va;
-               if(ph->p_type == ELF_PROG_INTERP)
-               {
-                       int maxlen = MIN(PGSIZE-ph->p_offset,sizeof(ei->interp));
-                       int len = strnlen(elf+ph->p_offset,maxlen);
-                       if(len < maxlen)
-                       {
-                               memcpy(ei->interp,elf+ph->p_offset,maxlen+1);
-                               ei->dynamic = 1;
-                       }
-                       else
-                               goto fail;
+       #endif
+
+       size_t phsz = elf64 ? sizeof(proghdr64_t) : sizeof(proghdr32_t);
+       uint16_t e_phnum = elf_field(elfhdr, e_phnum);
+       uint16_t e_phoff = elf_field(elfhdr, e_phoff);
+
+       /* Read in program headers. */
+       if (e_phnum > 10000 || e_phoff % (elf32 ? 4 : 8) != 0)
+         goto fail;
+       phdrs = kmalloc(e_phnum * phsz, 0);
+       f_off = e_phoff;
+       if (!phdrs || f->f_op->read(f, phdrs, e_phnum * phsz, &f_off) == -1)
+               goto fail;
+       for (int i = 0; i < e_phnum; i++) {
+               proghdr32_t* ph32 = (proghdr32_t*)phdrs + i;
+               proghdr64_t* ph64 = (proghdr64_t*)phdrs + i;
+               uint16_t p_type = elf_field(ph, p_type);
+               uintptr_t p_va = elf_field(ph, p_va);
+               uintptr_t p_offset = elf_field(ph, p_offset);
+               uintptr_t p_align = elf_field(ph, p_align);
+               uintptr_t p_memsz = elf_field(ph, p_memsz);
+               uintptr_t p_filesz = elf_field(ph, p_filesz);
+               uintptr_t p_flags = elf_field(ph, p_flags);
+
+               /* Here's the ld hack, mentioned above */
+               p_flags |= (writable ? ELF_PROT_WRITE : 0);
+               /* All mmaps need to be fixed to their VAs.  If the program wants it to
+                * be a writable region, we also need the region to be private. */
+               mm_flags = MAP_FIXED | (p_flags & ELF_PROT_WRITE ? MAP_PRIVATE : 0);
+
+               if (p_type == ELF_PROG_PHDR)
+                       ei->phdr = p_va;
+               else if (p_type == ELF_PROG_INTERP) {
+                       f_off = p_offset;
+                       ssize_t maxlen = sizeof(ei->interp);
+                       ssize_t bytes = f->f_op->read(f, ei->interp, maxlen, &f_off);
+                       if (bytes == -1)
+                         goto fail;
+
+                       maxlen = MIN(maxlen, bytes);
+                       if (strnlen(ei->interp, maxlen) == maxlen)
+                         goto fail;
+
+                       ei->dynamic = 1;
                }
-
-               if(ph->p_type == ELF_PROG_LOAD && ph->p_memsz)
-               {
-                       if(ph->p_align % PGSIZE)
+               else if (p_type == ELF_PROG_LOAD && p_memsz) {
+                       if (p_align % PGSIZE)
                                goto fail;
-                       if(ph->p_offset % PGSIZE != ph->p_va % PGSIZE)
+                       if (p_offset % PGSIZE != p_va % PGSIZE)
                                goto fail;
 
-                       uintptr_t filestart = ROUNDDOWN(ph->p_offset,PGSIZE);
-                       uintptr_t fileend = ph->p_offset+ph->p_filesz;
-                       uintptr_t filesz = fileend-filestart;
-
-                       uintptr_t memstart = ROUNDDOWN(ph->p_va,PGSIZE);
-                       uintptr_t memend = ROUNDUP(ph->p_va + ph->p_memsz,PGSIZE);
-                       uintptr_t memsz = memend-memstart;
-
-                       // mmap will zero the rest of the page if filesz % PGSIZE != 0
-                       if(filesz)
-                               // TODO: waterman, figure out proper permissions
-                               if(mmap(p, memstart+pgoffset*PGSIZE, filesz,
-                                       PROT_READ|PROT_WRITE|PROT_EXEC, MAP_FIXED,
-                                       fd, filestart/PGSIZE) == MAP_FAILED)
-                                       goto fail;
-
-                       filesz = ROUNDUP(filesz,PGSIZE);
-                       if(filesz < memsz)
-                               if(mmap(p, memstart+filesz+pgoffset*PGSIZE, memsz-filesz,
-                                       PROT_READ|PROT_WRITE|PROT_EXEC, MAP_FIXED|MAP_ANON,
-                                       -1, 0) == MAP_FAILED)
+                       uintptr_t filestart = ROUNDDOWN(p_offset, PGSIZE);
+                       uintptr_t filesz = p_offset + p_filesz - filestart;
+
+                       uintptr_t memstart = ROUNDDOWN(p_va, PGSIZE);
+                       uintptr_t memsz = ROUNDUP(p_va + p_memsz, PGSIZE) - memstart;
+                       memstart += pgoffset * PGSIZE;
+
+                       if (memstart + memsz > ei->highest_addr)
+                               ei->highest_addr = memstart + memsz;
+
+                       mm_perms = 0;
+                       mm_perms |= (p_flags & ELF_PROT_READ  ? PROT_READ : 0);
+                       mm_perms |= (p_flags & ELF_PROT_WRITE ? PROT_WRITE : 0);
+                       mm_perms |= (p_flags & ELF_PROT_EXEC  ? PROT_EXEC : 0);
+
+                       if (filesz) {
+                               /* Due to elf-ghetto-ness, we need to zero the first part of
+                                * the BSS from the last page of the data segment.  If we end
+                                * on a partial page, we map it in separately with
+                                * MAP_POPULATE so that we can zero the rest of it now. We
+                                * translate to the KVA so we don't need to worry about using
+                                * the proc's mapping */
+                               uintptr_t partial = PGOFF(filesz);
+
+                               if (filesz - partial) {
+                                       /* Map the complete pages. */
+                                       if (do_mmap(p, memstart, filesz - partial, mm_perms,
+                                                   mm_flags, f, filestart) == MAP_FAILED)
+                                               goto fail;
+                               }
+                               /* Note that we (probably) only need to do this zeroing the end
+                                * of a partial file page when we are dealing with
+                                * ELF_PROT_WRITE-able PHs, and not for all cases.  */
+                               if (partial) {
+                                       /* Need our own populated, private copy of the page so that
+                                        * we can zero the remainder - and not zero chunks of the
+                                        * real file in the page cache. */
+                                       mm_flags |= MAP_PRIVATE | MAP_POPULATE;
+
+                                       /* Map the final partial page. */
+                                       uintptr_t last_page = memstart + filesz - partial;
+                                       if (do_mmap(p, last_page, PGSIZE, mm_perms, mm_flags,
+                                                   f, filestart + filesz - partial) == MAP_FAILED)
+                                               goto fail;
+
+                                       /* Zero the end of it. */
+                                       pte_t *pte = pgdir_walk(p->env_pgdir, (void*)last_page, 0);
+                                       assert(pte);
+                                       void* last_page_kva = ppn2kva(PTE2PPN(*pte));
+                                       memset(last_page_kva + partial, 0, PGSIZE - partial);
+
+                                       filesz = ROUNDUP(filesz, PGSIZE);
+                               }
+                       }
+                       /* Any extra pages are mapped anonymously... (a bit weird) */
+                       if (filesz < memsz)
+                               if (do_mmap(p, memstart + filesz, memsz-filesz,
+                                           PROT_READ | PROT_WRITE, MAP_PRIVATE,
+                                               NULL, 0) == MAP_FAILED)
                                        goto fail;
                }
        }
-
-       ei->entry = elfhdr->e_entry + pgoffset*PGSIZE;
-       ei->phnum = elfhdr->e_phnum;
-
+       /* map in program headers anyway if not present in binary.
+        * useful for TLS in static programs. */
+       if (ei->phdr == -1) {
+               uintptr_t filestart = ROUNDDOWN(e_phoff, PGSIZE);
+               uintptr_t filesz = e_phoff + (e_phnum * phsz) - filestart;
+               void *phdr_addr = do_mmap(p, 0, filesz, PROT_READ | PROT_WRITE,
+                                         MAP_PRIVATE, f, filestart);
+               if (phdr_addr == MAP_FAILED)
+                       goto fail;
+               ei->phdr = (long)phdr_addr + e_phoff;
+       }
+       ei->entry = elf_field(elfhdr, e_entry) + pgoffset*PGSIZE;
+       ei->phnum = e_phnum;
+       ei->elf64 = elf64;
        ret = 0;
+       goto out;
 fail:
-       kfree(elf);
+       printk("[kernel] Load failed during loadelf of file %s!\n", file_name(f));
+out:
+       if (phdrs)
+               kfree(phdrs);
+       current = cur_proc;
        return ret;
 }
 
-int load_elf(struct proc* p, const char* fn)
+int load_elf(struct proc* p, struct file* f)
 {
-       struct elf_info ei,interp_ei;
-       int fd = open_file(p,fn,0,0);
-       if(fd == -1 || load_one_elf(p,fd,0,&ei))
+       elf_info_t ei, interp_ei;
+       if (load_one_elf(p, f, 0, &ei, FALSE))
                return -1;
-       close_file(p,fd);
 
-       if(ei.dynamic)
-       {
-               int fd2 = open_file(p,ei.interp,0,0);
-               if(fd2 == -1 || load_one_elf(p,fd2,1,&interp_ei))
+       if (ei.dynamic) {
+               struct file *interp = do_file_open(ei.interp, 0, 0);
+               if (!interp)
                        return -1;
-               close_file(p,fd2);
-
-               // fill in info for dynamic linker
-               elf_aux_t auxp[] = {{ELF_AUX_PHDR,ei.phdr},
-                                   {ELF_AUX_PHENT,sizeof(proghdr_t)},
-                                   {ELF_AUX_PHNUM,ei.phnum},
-                                   {ELF_AUX_ENTRY,ei.entry},
-                                   {0,0}};
-
-               // put auxp after argv, envp in procinfo
-               int auxp_pos = -1;
-               for(int i = 0, zeros = 0; i < PROCINFO_MAX_ARGP; i++)
-                       if(p->env_procinfo->argp[i] == NULL)
-                               if(++zeros == 2)
-                                       auxp_pos = i+1;
-               if(auxp_pos == -1 ||
-                  auxp_pos+sizeof(auxp)/sizeof(char*) >= PROCINFO_MAX_ARGP)
+               /* Load dynamic linker one page into the address space */
+               int error = load_one_elf(p, interp, 1, &interp_ei, TRUE);
+               kref_put(&interp->f_kref);
+               if (error)
                        return -1;
-               memcpy(p->env_procinfo->argp+auxp_pos,auxp,sizeof(auxp));
        }
 
-       intptr_t core0_entry = ei.dynamic ? interp_ei.entry : ei.entry;
+       // fill in auxiliary info for dynamic linker/runtime
+       elf_aux_t auxp[] = {{ELF_AUX_PHDR, ei.phdr},
+                           {ELF_AUX_PHENT, sizeof(proghdr32_t)},
+                           {ELF_AUX_PHNUM, ei.phnum},
+                           {ELF_AUX_ENTRY, ei.entry},
+                           #ifdef __sparc_v8__
+                           {ELF_AUX_HWCAP, ELF_HWCAP_SPARC_FLUSH},
+                           #endif
+                           {0, 0}};
+
+       // put auxp after argv, envp in procinfo
+       int auxp_pos = -1;
+       for (int i = 0, zeros = 0; i < PROCINFO_MAX_ARGP; i++)
+               if (p->procinfo->argp[i] == NULL)
+                       if (++zeros == 2)
+                               auxp_pos = i + 1;
+       if (auxp_pos == -1 ||
+           auxp_pos + sizeof(auxp) / sizeof(char*) >= PROCINFO_MAX_ARGP)
+               return -1;
+       memcpy(p->procinfo->argp+auxp_pos,auxp,sizeof(auxp));
+
+       uintptr_t core0_entry = ei.dynamic ? interp_ei.entry : ei.entry;
        proc_init_trapframe(&p->env_tf,0,core0_entry,USTACKTOP);
        p->env_entry = ei.entry;
 
+       int flags = MAP_FIXED | MAP_ANONYMOUS;
+       #ifdef __sparc_v8__
+       flags |= MAP_POPULATE; // SPARC stacks must be mapped in
+       #endif
        uintptr_t stacksz = USTACK_NUM_PAGES*PGSIZE;
-       if(mmap(p,USTACKTOP-stacksz,stacksz,PROT_READ|PROT_WRITE,
-               MAP_FIXED|MAP_ANON,-1,0) == MAP_FAILED)
-               return -1;
-
-       return 0;
-}
-
-intreg_t sys_exec(struct proc* p, const char fn[MAX_PATH_LEN], procinfo_t* pi)
-{
-       if(p->state != PROC_RUNNING_S)
+       if (do_mmap(p, USTACKTOP-stacksz, stacksz, PROT_READ | PROT_WRITE,
+                   flags, NULL, 0) == MAP_FAILED)
                return -1;
 
-       char kfn[MAX_PATH_LEN];
-       if(memcpy_from_user(p,kfn,fn,MAX_PATH_LEN))
-               return -1;
-
-       if(memcpy_from_user(p,p->env_procinfo,pi,sizeof(procinfo_t)))
-       {
-               proc_destroy(p);
-               return -1;
-       }
-       proc_init_procinfo(p);
-
-       env_segment_free(p,0,USTACKTOP);
-
-       if(load_elf(p,kfn))
-       {
-               proc_destroy(p);
-               return -1;
-       }
-       *current_tf = p->env_tf;
+       // Set the heap bottom and top to just past where the text 
+       // region has been loaded
+       p->heap_top = (void*)ei.highest_addr;
+       p->procinfo->heap_bottom = p->heap_top;
 
        return 0;
 }