Re: [Qemu-devel] [PATCH 10/10] linux-user: remove unused variables

[Alexander Graf]

On 14.06.2011, at 19:36, Michael S. Tsirkin wrote:

> Signed-off-by: Michael S. Tsirkin <address@hidden>
> ---
> linux-user/flatload.c  |   10 ++++++----
> linux-user/linuxload.c |   25 +------------------------
> linux-user/main.c      |    6 +++---
> linux-user/signal.c    |    5 -----
> linux-user/syscall.c   |    6 ------
> 5 files changed, 10 insertions(+), 42 deletions(-)
> 
> diff --git a/linux-user/flatload.c b/linux-user/flatload.c
> index cd7af7c..2933c5f 100644
> --- a/linux-user/flatload.c
> +++ b/linux-user/flatload.c
> @@ -379,12 +379,14 @@ static int load_flat_file(struct linux_binprm * bprm,
>     abi_long result;
>     abi_ulong realdatastart = 0;
>     abi_ulong text_len, data_len, bss_len, stack_len, flags;
> -    abi_ulong memp = 0; /* for finding the brk area */
>     abi_ulong extra;
>     abi_ulong reloc = 0, rp;
>     int i, rev, relocs = 0;
>     abi_ulong fpos;
> -    abi_ulong start_code, end_code;
> +    abi_ulong start_code;
> +#ifdef DEBUG
> +    abi_ulong end_code;
> +#endif
>     abi_ulong indx_len;
> 
>     hdr = ((struct flat_hdr *) bprm->buf);            /* exec-header */
> @@ -491,7 +493,6 @@ static int load_flat_file(struct linux_binprm * bprm,
>         }
> 
>         reloc = datapos + (ntohl(hdr->reloc_start) - text_len);
> -        memp = realdatastart;
> 
>     } else {
> 
> @@ -506,7 +507,6 @@ static int load_flat_file(struct linux_binprm * bprm,
>         realdatastart = textpos + ntohl(hdr->data_start);
>         datapos = realdatastart + indx_len;
>         reloc = (textpos + ntohl(hdr->reloc_start) + indx_len);
> -        memp = textpos;
> 
> #ifdef CONFIG_BINFMT_ZFLAT
> #error code needs checking
> @@ -552,7 +552,9 @@ static int load_flat_file(struct linux_binprm * bprm,
> 
>     /* The main program needs a little extra setup in the task structure */
>     start_code = textpos + sizeof (struct flat_hdr);
> +#ifdef DEBUG
>     end_code = textpos + text_len;
> +#endif
> 
>     DBG_FLT("%s %s: TEXT=%x-%x DATA=%x-%x BSS=%x-%x\n",
>             id ? "Lib" : "Load", bprm->filename,
> diff --git a/linux-user/linuxload.c b/linux-user/linuxload.c
> index ac8c486..62ebc7e 100644
> --- a/linux-user/linuxload.c
> +++ b/linux-user/linuxload.c
> @@ -26,22 +26,6 @@ abi_long memcpy_to_target(abi_ulong dest, const void *src,
>     return 0;
> }
> 
> -static int in_group_p(gid_t g)
> -{
> -    /* return TRUE if we're in the specified group, FALSE otherwise */
> -    int              ngroup;
> -    int              i;
> -    gid_t    grouplist[NGROUPS];
> -
> -    ngroup = getgroups(NGROUPS, grouplist);
> -    for(i = 0; i < ngroup; i++) {
> -     if(grouplist[i] == g) {
> -         return 1;
> -     }
> -    }
> -    return 0;
> -}
> -
> static int count(char ** vec)
> {
>     int               i;
> @@ -57,7 +41,7 @@ static int prepare_binprm(struct linux_binprm *bprm)
> {
>     struct stat               st;
>     int mode;
> -    int retval, id_change;
> +    int retval;
> 
>     if(fstat(bprm->fd, &st) < 0) {
>       return(-errno);
> @@ -73,14 +57,10 @@ static int prepare_binprm(struct linux_binprm *bprm)
> 
>     bprm->e_uid = geteuid();
>     bprm->e_gid = getegid();
> -    id_change = 0;
> 
>     /* Set-uid? */
>     if(mode & S_ISUID) {
>       bprm->e_uid = st.st_uid;
> -     if(bprm->e_uid != geteuid()) {
> -         id_change = 1;
> -     }
>     }
> 
>     /* Set-gid? */
> @@ -91,9 +71,6 @@ static int prepare_binprm(struct linux_binprm *bprm)
>      */
>     if ((mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) {
>       bprm->e_gid = st.st_gid;
> -     if (!in_group_p(bprm->e_gid)) {
> -             id_change = 1;
> -     }
>     }
> 
>     retval = read(bprm->fd, bprm->buf, BPRM_BUF_SIZE);
> diff --git a/linux-user/main.c b/linux-user/main.c
> index 04da0a4..9b995e5 100644
> --- a/linux-user/main.c
> +++ b/linux-user/main.c
> @@ -2053,15 +2053,15 @@ void cpu_loop(CPUMIPSState *env)
>             } else {
>                 int nb_args;
>                 abi_ulong sp_reg;
> -                abi_ulong arg5 = 0, arg6 = 0, arg7 = 0, arg8 = 0;
> +                abi_ulong arg5 = 0, arg6 = 0;
> 
>                 nb_args = mips_syscall_args[syscall_num];
>                 sp_reg = env->active_tc.gpr[29];
>                 switch (nb_args) {
>                 /* these arguments are taken from the stack */
>                 /* FIXME - what to do if get_user() fails? */
> -                case 8: get_user_ual(arg8, sp_reg + 28);
> -                case 7: get_user_ual(arg7, sp_reg + 24);
> +                case 8: /* get_user_ual(arg8, sp_reg + 28); */
> +                case 7: /* get_user_ual(arg7, sp_reg + 24); */

I'd prefer to see these and the respective variable definitions #if 0'd with a 
comment, stating that they're currently unused.

>                 case 6: get_user_ual(arg6, sp_reg + 20);
>                 case 5: get_user_ual(arg5, sp_reg + 16);
>                 default:
> diff --git a/linux-user/signal.c b/linux-user/signal.c
> index 11b25be..685ae61 100644
> --- a/linux-user/signal.c
> +++ b/linux-user/signal.c
> @@ -2080,7 +2080,6 @@ long do_sigreturn(CPUState *env)
>         uint32_t up_psr, pc, npc;
>         target_sigset_t set;
>         sigset_t host_set;
> -        abi_ulong fpu_save_addr;
>         int err, i;
> 
>         sf_addr = env->regwptr[UREG_FP];
> @@ -2120,8 +2119,6 @@ long do_sigreturn(CPUState *env)
>               err |= __get_user(env->regwptr[i + UREG_I0], 
> &sf->info.si_regs.u_regs[i+8]);
>       }
> 
> -        err |= __get_user(fpu_save_addr, &sf->fpu_save);

This probably goes along the same line. Please keep the code around - it seems 
related to the commented out code below.

> -
>         //if (fpu_save)
>         //        err |= restore_fpu_state(env, fpu_save);
> 
> @@ -2228,7 +2225,6 @@ void sparc64_set_context(CPUSPARCState *env)
>     target_mc_gregset_t *grp;
>     abi_ulong pc, npc, tstate;
>     abi_ulong fp, i7, w_addr;
> -    unsigned char fenab;
>     int err;
>     unsigned int i;
> 
> @@ -2293,7 +2289,6 @@ void sparc64_set_context(CPUSPARCState *env)
>     if (put_user(i7, w_addr + offsetof(struct target_reg_window, ins[7]), 
>                  abi_ulong) != 0)
>         goto do_sigsegv;
> -    err |= __get_user(fenab, &(ucp->tuc_mcontext.mc_fpregs.mcfpu_enab));

not sure here - might be the same as above?

>     err |= __get_user(env->fprs, &(ucp->tuc_mcontext.mc_fpregs.mcfpu_fprs));
>     {
>         uint32_t *src, *dst;
> diff --git a/linux-user/syscall.c b/linux-user/syscall.c
> index 5cb27c7..71395d5 100644
> --- a/linux-user/syscall.c
> +++ b/linux-user/syscall.c
> @@ -3751,7 +3751,6 @@ static abi_long do_get_thread_area(CPUX86State *env, 
> abi_ulong ptr)
> #ifndef TARGET_ABI32
> static abi_long do_arch_prctl(CPUX86State *env, int code, abi_ulong addr)
> {
> -    abi_long ret;
>     abi_ulong val;
>     int idx;
> 
> @@ -3776,7 +3775,6 @@ static abi_long do_arch_prctl(CPUX86State *env, int 
> code, abi_ulong addr)
>             return -TARGET_EFAULT;
>         break;
>     default:
> -        ret = -TARGET_EINVAL;

I'm fairly sure this was supposed to be "return -TARGET_EINVAL".

>         break;
>     }
>     return 0;
> @@ -7058,18 +7056,14 @@ abi_long do_syscall(void *cpu_env, int num, abi_long 
> arg1,
>     case TARGET_NR_osf_sigprocmask:
>         {
>             abi_ulong mask;
> -            int how = arg1;
>             sigset_t set, oldset;
> 
>             switch(arg1) {
>             case TARGET_SIG_BLOCK:
> -                how = SIG_BLOCK;
>                 break;
>             case TARGET_SIG_UNBLOCK:
> -                how = SIG_UNBLOCK;
>                 break;
>             case TARGET_SIG_SETMASK:
> -                how = SIG_SETMASK;

why go through the effort of setting "how" and then not using it? I'm pretty 
sure this is a bug as well. A few lines down is the following code:

   sigprocmask(arg1, &set, &oldset);

which in TARGET_NR_sigprocmask would be:

  ret = get_errno(sigprocmask(how, &set, &oldset));

So we end up sending guest masks to the host. Richard, this is Alpha specific 
code. Mind to double-check?


Alex