On [Sat, 23.02.2008 12:00], Takashi Yoshii wrote: > getgroups() and getgroups32() returns NGROUPS_MAX when both its two args are > zero. But because we pass a ptr to allocated space as 2nd arg, this function > are interfered. The patch attached fixed it. > /yoshii > --- > linux-user/syscall.c: fix getgroups{,32} when both args are zero. >
My version of patch to fix same problem: getgroups: return total number of supplementary group IDs for the process if size == 0 diff --git a/linux-user/syscall.c b/linux-user/syscall.c index ad97871..96a11a9 100644 --- a/linux-user/syscall.c +++ b/linux-user/syscall.c @@ -5029,6 +5029,8 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1, grouplist = alloca(gidsetsize * sizeof(gid_t)); ret = get_errno(getgroups(gidsetsize, grouplist)); + if (gidsetsize == 0) + break; if (!is_error(ret)) { target_grouplist = lock_user(VERIFY_WRITE, arg2, gidsetsize * 2, 0); if (!target_grouplist) @@ -5179,6 +5181,8 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1, grouplist = alloca(gidsetsize * sizeof(gid_t)); ret = get_errno(getgroups(gidsetsize, grouplist)); + if (gidsetsize == 0) + break; if (!is_error(ret)) { target_grouplist = lock_user(VERIFY_WRITE, arg2, gidsetsize * 4, 0); if (!target_grouplist) { Another patch for getgroups: Trivial optimization of getgroups syscall implementation: swap only returned groups, not all group in list. diff --git a/linux-user/syscall.c b/linux-user/syscall.c index 6f2872f..ad97871 100644 --- a/linux-user/syscall.c +++ b/linux-user/syscall.c @@ -5033,7 +5033,7 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1, target_grouplist = lock_user(VERIFY_WRITE, arg2, gidsetsize * 2, 0); if (!target_grouplist) goto efault; - for(i = 0;i < gidsetsize; i++) + for(i = 0;i < ret; i++) target_grouplist[i] = tswap16(grouplist[i]); unlock_user(target_grouplist, arg2, gidsetsize * 2); } @@ -5185,7 +5185,7 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1, ret = -TARGET_EFAULT; goto fail; } - for(i = 0;i < gidsetsize; i++) + for(i = 0;i < ret; i++) target_grouplist[i] = tswap32(grouplist[i]); unlock_user(target_grouplist, arg2, gidsetsize * 4); } It makes getgroups much faster in some cases. -- Regards, Kirill A. Shutemov + Belarus, Minsk + Velesys Ltd, http://www.velesys.com/ + ALT Linux Team, http://www.altlinux.com/
signature.asc
Description: Digital signature