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提交 4655d42e 创建 作者: Robert Morris's avatar Robert Morris
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copyout() copies data to a va in a pagetable, for exec() &c

usertest that passes too many arguments, break exec
上级 a9183883
隐藏空白字符变更
内嵌 并排
正在显示 包含 95 行增加 和 45 行删除
defs.h
浏览文件 @ 4655d42e
......@@ -165,6 +165,7 @@ int loaduvm(pde_t*, char*, struct inode *, uint, uint);
pde_t* copyuvm(pde_t*,uint);
void switchuvm(struct proc*);
void switchkvm();
int copyout(pde_t *pgdir, uint va, void *buf, uint len);
// number of elements in fixed-size array
#define NELEM(x) (sizeof(x)/sizeof((x)[0]))
exec.c
浏览文件 @ 4655d42e
......@@ -9,16 +9,13 @@
int
exec(char *path, char **argv)
{
char *mem, *s, *last;
int i, argc, arglen, len, off;
uint sz, sp, spbottom, argp;
char *s, *last;
int i, off;
uint sz = 0;
struct elfhdr elf;
struct inode *ip;
struct inode *ip = 0;
struct proghdr ph;
pde_t *pgdir, *oldpgdir;
pgdir = 0;
sz = 0;
pde_t *pgdir = 0, *oldpgdir;
if((ip = namei(path)) == 0)
return -1;
......@@ -48,40 +45,65 @@ exec(char *path, char **argv)
}
iunlockput(ip);
// Allocate and initialize stack at sz
sz = spbottom = PGROUNDUP(sz);
// Allocate a one-page stack at the next page boundary
sz = PGROUNDUP(sz);
if(!(sz = allocuvm(pgdir, sz, sz + PGSIZE)))
goto bad;
mem = uva2ka(pgdir, (char *)spbottom);
arglen = 0;
for(argc=0; argv[argc]; argc++)
arglen += strlen(argv[argc]) + 1;
arglen = (arglen+3) & ~3;
sp = sz;
argp = sz - arglen - 4*(argc+1);
// XXX rtm: does the following code work if the
// arguments &c do not fit in one page?
// Copy argv strings and pointers to stack.
*(uint*)(mem+argp-spbottom + 4*argc) = 0; // argv[argc]
for(i=argc-1; i>=0; i--){
len = strlen(argv[i]) + 1;
sp -= len;
memmove(mem+sp-spbottom, argv[i], len);
*(uint*)(mem+argp-spbottom + 4*i) = sp; // argv[i]
// initialize stack content:
// "argumentN" -- nul-terminated string
// ...
// "argument0"
// 0 -- argv[argc]
// address of argumentN
// ...
// address of argument0 -- argv[0]
// address of address of argument0 -- argv argument to main()
// argc -- argc argument to main()
// ffffffff -- return PC for main() call
uint sp = sz;
// count arguments
int argc;
for(argc = 0; argv[argc]; argc++)
;
if(argc >= MAXARG)
goto bad;
// push strings and remember where they are
uint strings[MAXARG];
for(i = argc - 1; i >= 0; --i){
sp -= strlen(argv[i]) + 1;
strings[i] = sp;
copyout(pgdir, sp, argv[i], strlen(argv[i]) + 1);
}
// push 0 for argv[argc]
sp -= 4;
int zero = 0;
copyout(pgdir, sp, &zero, 4);
// push argv[] elements
for(i = argc - 1; i >= 0; --i){
sp -= 4;
copyout(pgdir, sp, &strings[i], 4);
}
// Stack frame for main(argc, argv), below arguments.
sp = argp;
// push argv
uint argvaddr = sp;
sp -= 4;
*(uint*)(mem+sp-spbottom) = argp;
copyout(pgdir, sp, &argvaddr, 4);
// push argc
sp -= 4;
*(uint*)(mem+sp-spbottom) = argc;
copyout(pgdir, sp, &argc, 4);
// push 0 in case main returns
sp -= 4;
*(uint*)(mem+sp-spbottom) = 0xffffffff; // fake return pc
uint ffffffff = 0xffffffff;
copyout(pgdir, sp, &ffffffff, 4);
// Save program name for debugging.
for(last=s=path; *s; s++)
......@@ -103,6 +125,7 @@ exec(char *path, char **argv)
return 0;
bad:
cprintf("kernel: exec failed\n");
if(pgdir) freevm(pgdir);
iunlockput(ip);
return -1;
......
param.h
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......@@ -7,4 +7,6 @@
#define NINODE 50 // maximum number of active i-nodes
#define NDEV 10 // maximum major device number
#define ROOTDEV 1 // device number of file system root disk
#define USERTOP 0xA0000 // end of user address space
#define PHYSTOP 0x1000000 // use phys mem up to here as free pool
#define MAXARG 32 // max exec arguments
sysfile.c
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......@@ -344,7 +344,7 @@ sys_chdir(void)
int
sys_exec(void)
{
char *path, *argv[20];
char *path, *argv[MAXARG];
int i;
uint uargv, uarg;
......
usertests.c
浏览文件 @ 4655d42e
......@@ -1445,11 +1445,11 @@ bigargtest(void)
ppid = getpid();
pid = fork();
if(pid == 0){
char *args[100];
char *args[32];
int i;
for(i = 0; i < 99; i++)
args[i] = "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx";
args[99] = 0;
for(i = 0; i < 32-1; i++)
args[i] = "bigargs test: failed\n ";
args[32-1] = 0;
printf(stdout, "bigarg test\n");
exec("echo", args);
printf(stdout, "bigarg test ok\n");
......@@ -1472,7 +1472,7 @@ main(int argc, char *argv[])
}
close(open("usertests.ran", O_CREATE));
// bigargtest();
bigargtest();
bsstest();
sbrktest();
validatetest();
......
vm.c
浏览文件 @ 4655d42e
......@@ -6,8 +6,6 @@
#include "proc.h"
#include "elf.h"
#define USERTOP 0xA0000
static pde_t *kpgdir; // for use in scheduler()
// Set up CPU's kernel segment descriptors.
......@@ -126,7 +124,7 @@ setupkvm(void)
{
pde_t *pgdir;
extern char etext[];
char *rwstart = PGROUNDDOWN(etext) - PGSIZE;
char *rwstart = PGROUNDDOWN(etext);
uint rwlen = (uint)rwstart - 0x100000;
// Allocate page directory
......@@ -193,7 +191,10 @@ char*
uva2ka(pde_t *pgdir, char *uva)
{
pte_t *pte = walkpgdir(pgdir, uva, 0);
if(pte == 0) return 0;
if((*pte & PTE_P) == 0)
return 0;
if((*pte & PTE_U) == 0)
return 0;
uint pa = PTE_ADDR(*pte);
return (char *)pa;
}
......@@ -326,3 +327,26 @@ bad:
return 0;
}
// copy some data to user address va in page table pgdir.
// most useful when pgdir is not the current page table.
// returns 1 if everthing OK, 0 on error.
// uva2ka ensures this only works for PTE_U pages.
int
copyout(pde_t *pgdir, uint va, void *xbuf, uint len)
{
char *buf = (char *) xbuf;
while(len > 0){
uint va0 = (uint)PGROUNDDOWN(va);
char *pa0 = uva2ka(pgdir, (char*) va0);
if(pa0 == 0)
return 0;
uint n = PGSIZE - (va - va0);
if(n > len)
n = len;
memmove(pa0 + (va - va0), buf, n);
len -= n;
buf += n;
va = va0 + PGSIZE;
}
return 1;
}
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