diff options
Diffstat (limited to 'kernel/exec.c')
| -rw-r--r-- | kernel/exec.c | 27 |
1 files changed, 20 insertions, 7 deletions
diff --git a/kernel/exec.c b/kernel/exec.c index 3c468e1..aee9345 100644 --- a/kernel/exec.c +++ b/kernel/exec.c @@ -7,7 +7,17 @@ #include "defs.h" #include "elf.h" -static int loadseg(pde_t *pgdir, uint64 addr, struct inode *ip, uint offset, uint sz); +static int loadseg(pde_t *, uint64, uint, struct inode *, uint, uint); + +int flags2perm(int flags) +{ + int perm = 0; + if(flags & 0x1) + perm = PTE_X; + if(flags & 0x2) + perm |= PTE_W; + return perm; +} int exec(char *path, char **argv) @@ -32,6 +42,7 @@ exec(char *path, char **argv) // Check ELF header if(readi(ip, 0, (uint64)&elf, 0, sizeof(elf)) != sizeof(elf)) goto bad; + if(elf.magic != ELF_MAGIC) goto bad; @@ -48,13 +59,15 @@ exec(char *path, char **argv) goto bad; if(ph.vaddr + ph.memsz < ph.vaddr) goto bad; + if(ph.align != PGSIZE) + goto bad; + uint64 e = PGROUNDUP(ph.vaddr + ph.memsz); uint64 sz1; - if((sz1 = uvmalloc(pagetable, sz, ph.vaddr + ph.memsz, PTE_X|PTE_W)) == 0) + if((sz1 = uvmalloc(pagetable, sz, e, flags2perm(ph.flags))) == 0) goto bad; sz = sz1; - if((ph.vaddr % PGSIZE) != 0) - goto bad; - if(loadseg(pagetable, ph.vaddr, ip, ph.off, ph.filesz) < 0) + uint64 s = PGROUNDDOWN(ph.vaddr); + if(loadseg(pagetable, s, ph.vaddr - s, ip, ph.off, ph.filesz) < 0) goto bad; } iunlockput(ip); @@ -134,7 +147,7 @@ exec(char *path, char **argv) // and the pages from va to va+sz must already be mapped. // Returns 0 on success, -1 on failure. static int -loadseg(pagetable_t pagetable, uint64 va, struct inode *ip, uint offset, uint sz) +loadseg(pagetable_t pagetable, uint64 va, uint poff, struct inode *ip, uint offset, uint sz) { uint i, n; uint64 pa; @@ -147,7 +160,7 @@ loadseg(pagetable_t pagetable, uint64 va, struct inode *ip, uint offset, uint sz n = sz - i; else n = PGSIZE; - if(readi(ip, 0, (uint64)pa, offset+i, n) != n) + if(readi(ip, 0, (uint64)pa+poff, offset+i, n) != n) return -1; } |