f32f3638f4
- Got rid of dummy proc[0]. Now proc[0] is init. - Added initcode.S to exec /init, so that /init is just a regular binary. - Moved exec out of sysfile to exec.c - Moved code dealing with fs guts (like struct inode) from sysfile.c to fs.c. Code dealing with system call arguments stays in sysfile.c - Refactored directory routines in fs.c; should be simpler. - Changed iget to return *unlocked* inode structure. This solves the lookup-then-use race in namei without introducing deadlocks. It also enabled getting rid of the dummy proc[0].
137 lines
2.5 KiB
C
137 lines
2.5 KiB
C
#include "types.h"
|
|
#include "stat.h"
|
|
#include "param.h"
|
|
#include "mmu.h"
|
|
#include "proc.h"
|
|
#include "defs.h"
|
|
#include "x86.h"
|
|
#include "traps.h"
|
|
#include "syscall.h"
|
|
#include "spinlock.h"
|
|
#include "buf.h"
|
|
#include "fs.h"
|
|
#include "fsvar.h"
|
|
#include "elf.h"
|
|
#include "file.h"
|
|
#include "fcntl.h"
|
|
|
|
int
|
|
exec(char *path, char **argv)
|
|
{
|
|
uint sz, sp, p1, p2;
|
|
int i, nargs, argbytes, len;
|
|
struct inode *ip;
|
|
struct elfhdr elf;
|
|
struct proghdr ph;
|
|
char *mem;
|
|
char *s, *last;
|
|
|
|
sz = 0;
|
|
mem = 0;
|
|
|
|
if((ip = namei(path)) == 0)
|
|
return -1;
|
|
|
|
if(readi(ip, (char*)&elf, 0, sizeof(elf)) < sizeof(elf))
|
|
goto bad;
|
|
|
|
if(elf.magic != ELF_MAGIC)
|
|
goto bad;
|
|
|
|
for(i = 0; i < elf.phnum; i++){
|
|
if(readi(ip, (char*)&ph, elf.phoff + i * sizeof(ph),
|
|
sizeof(ph)) != sizeof(ph))
|
|
goto bad;
|
|
if(ph.type != ELF_PROG_LOAD)
|
|
continue;
|
|
if(ph.memsz < ph.filesz)
|
|
goto bad;
|
|
sz += ph.memsz;
|
|
}
|
|
|
|
sz += 4096 - (sz % 4096);
|
|
sz += 4096;
|
|
|
|
mem = kalloc(sz);
|
|
if(mem == 0)
|
|
goto bad;
|
|
memset(mem, 0, sz);
|
|
|
|
argbytes = 0;
|
|
for(i = 0; argv[i]; i++){
|
|
len = strlen(argv[i]);
|
|
argbytes += len + 1;
|
|
}
|
|
nargs = i;
|
|
|
|
// argn\0
|
|
// ...
|
|
// arg0\0
|
|
// 0
|
|
// ptr to argn
|
|
// ...
|
|
// 12: ptr to arg0
|
|
// 8: argv (points to ptr to arg0)
|
|
// 4: argc
|
|
// 0: fake return pc
|
|
sp = sz - argbytes - (nargs+1)*4 - 4 - 4 - 4;
|
|
*(uint*)(mem + sp) = 0xffffffff;
|
|
*(uint*)(mem + sp + 4) = nargs;
|
|
*(uint*)(mem + sp + 8) = (uint)(sp + 12);
|
|
|
|
p1 = sp + 12;
|
|
p2 = sp + 12 + (nargs + 1) * 4;
|
|
for(i = 0; i < nargs; i++){
|
|
len = strlen(argv[i]);
|
|
memmove(mem + p2, argv[i], len + 1);
|
|
*(uint*)(mem + p1) = p2;
|
|
p1 += 4;
|
|
p2 += len + 1;
|
|
}
|
|
*(uint*)(mem + p1) = 0;
|
|
|
|
// Save name for debugging.
|
|
for(last=s=path; *s; s++)
|
|
if(*s == '/')
|
|
last = s+1;
|
|
safestrcpy(cp->name, last, sizeof cp->name);
|
|
|
|
// commit to the new image.
|
|
kfree(cp->mem, cp->sz);
|
|
cp->sz = sz;
|
|
cp->mem = mem;
|
|
mem = 0;
|
|
|
|
for(i = 0; i < elf.phnum; i++){
|
|
if(readi(ip, (char*)&ph, elf.phoff + i * sizeof(ph),
|
|
sizeof(ph)) != sizeof(ph))
|
|
goto bad2;
|
|
if(ph.type != ELF_PROG_LOAD)
|
|
continue;
|
|
if(ph.va + ph.memsz > sz)
|
|
goto bad2;
|
|
if(readi(ip, cp->mem + ph.va, ph.offset, ph.filesz) != ph.filesz)
|
|
goto bad2;
|
|
memset(cp->mem + ph.va + ph.filesz, 0, ph.memsz - ph.filesz);
|
|
}
|
|
|
|
iput(ip);
|
|
|
|
cp->tf->eip = elf.entry;
|
|
cp->tf->esp = sp;
|
|
setupsegs(cp);
|
|
|
|
return 0;
|
|
|
|
bad:
|
|
if(mem)
|
|
kfree(mem, sz);
|
|
iput(ip);
|
|
return -1;
|
|
|
|
bad2:
|
|
iput(ip);
|
|
proc_exit();
|
|
return 0;
|
|
}
|