Imbus/xv6-riscv-kernel
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make new code like old code

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Variable declarations at top of function,
separate from initialization.

Use == 0 instead of ! for checking pointers.

Consistent spacing around {, *, casts.

Declare 0-parameter functions as (void) not ().

Integer valued functions return -1 on failure, 0 on success.
This commit is contained in:
Russ Cox 2011-01-11 13:01:13 -05:00
parent 240679608c
commit 1a81e38b17
21 changed files with 227 additions and 199 deletions
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24
exec.c
View file

@ -10,16 +10,17 @@ int
exec(char *path, char **argv)
{
char *s, *last;
int i, off;
uint sz = 0;
int i, off, argc;
uint sz, sp, strings[MAXARG];
struct elfhdr elf;
struct inode *ip = 0;
struct inode *ip;
struct proghdr ph;
pde_t *pgdir = 0, *oldpgdir;
pde_t *pgdir, *oldpgdir;
if((ip = namei(path)) == 0)
return -1;
ilock(ip);
pgdir = 0;
// Check ELF header
if(readi(ip, (char*)&elf, 0, sizeof(elf)) < sizeof(elf))
@ -27,10 +28,11 @@ exec(char *path, char **argv)
if(elf.magic != ELF_MAGIC)
goto bad;
if(!(pgdir = setupkvm()))
if((pgdir = setupkvm()) == 0)
goto bad;
// Load program into memory.
sz = 0;
for(i=0, off=elf.phoff; i<elf.phnum; i++, off+=sizeof(ph)){
if(readi(ip, (char*)&ph, off, sizeof(ph)) != sizeof(ph))
goto bad;
@ -38,9 +40,9 @@ exec(char *path, char **argv)
continue;
if(ph.memsz < ph.filesz)
goto bad;
if(!(sz = allocuvm(pgdir, sz, ph.va + ph.memsz)))
if((sz = allocuvm(pgdir, sz, ph.va + ph.memsz)) == 0)
goto bad;
if(!loaduvm(pgdir, (char *)ph.va, ip, ph.offset, ph.filesz))
if(loaduvm(pgdir, (char*)ph.va, ip, ph.offset, ph.filesz) < 0)
goto bad;
}
iunlockput(ip);
@ -48,7 +50,7 @@ exec(char *path, char **argv)
// Allocate a one-page stack at the next page boundary
sz = PGROUNDUP(sz);
if(!(sz = allocuvm(pgdir, sz, sz + PGSIZE)))
if((sz = allocuvm(pgdir, sz, sz + PGSIZE)) == 0)
goto bad;
// initialize stack content:
@ -64,24 +66,22 @@ exec(char *path, char **argv)
// argc -- argc argument to main()
// ffffffff -- return PC for main() call
uint sp = sz;
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);
}
#define PUSH(x) { int xx = (int)(x); sp -= 4; copyout(pgdir, sp, &xx, 4); }
#define PUSH(x){ int xx = (int)(x); sp -= 4; copyout(pgdir, sp, &xx, 4); }
PUSH(0); // argv[argc] is zero