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linux-user: Use ARRAY_SIZE with bitmask_transtbl
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Rather than using a zero tuple to end the table, use a macro
to apply ARRAY_SIZE and pass that on to the convert functions.

This fixes two bugs in which the conversion functions required
that both the target and host masks be non-zero in order to
continue, rather than require both target and host masks be
zero in order to terminate.

This affected mmap_flags_tbl when the host does not support
all of the flags we wish to convert (e.g. MAP_UNINITIALIZED).
Mapping these flags to zero is good enough, and matches how
the kernel ignores bits that are unknown.

Fixes: 4b840f9 ("linux-user: Populate more bits in mmap_flags_tbl")
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
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rth7680 committed Aug 9, 2023
1 parent 9ab8d07 commit a05cee9
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Showing 4 changed files with 25 additions and 22 deletions.
2 changes: 2 additions & 0 deletions bsd-user/syscall_defs.h
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Original file line number Diff line number Diff line change
Expand Up @@ -227,7 +227,9 @@ type safe_##name(type1 arg1, type2 arg2, type3 arg3, type4 arg4, \
}

/* So far all target and host bitmasks are the same */
#undef target_to_host_bitmask
#define target_to_host_bitmask(x, tbl) (x)
#undef host_to_target_bitmask
#define host_to_target_bitmask(x, tbl) (x)

#endif /* SYSCALL_DEFS_H */
15 changes: 11 additions & 4 deletions include/exec/user/thunk.h
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Original file line number Diff line number Diff line change
Expand Up @@ -193,10 +193,17 @@ static inline int thunk_type_align(const argtype *type_ptr, int is_host)
}
}

unsigned int target_to_host_bitmask(unsigned int target_mask,
const bitmask_transtbl * trans_tbl);
unsigned int host_to_target_bitmask(unsigned int host_mask,
const bitmask_transtbl * trans_tbl);
unsigned int target_to_host_bitmask_len(unsigned int target_mask,
const bitmask_transtbl *trans_tbl,
size_t trans_len);
unsigned int host_to_target_bitmask_len(unsigned int host_mask,
const bitmask_transtbl * trans_tbl,
size_t trans_len);

#define target_to_host_bitmask(M, T) \
target_to_host_bitmask_len(M, T, ARRAY_SIZE(T))
#define host_to_target_bitmask(M, T) \
host_to_target_bitmask_len(M, T, ARRAY_SIZE(T))

void thunk_init(unsigned int max_structs);

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6 changes: 0 additions & 6 deletions linux-user/syscall.c
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Original file line number Diff line number Diff line change
Expand Up @@ -455,7 +455,6 @@ static const bitmask_transtbl fcntl_flags_tbl[] = {
#if TARGET_O_LARGEFILE != 0 || O_LARGEFILE != 0
{ TARGET_O_LARGEFILE, TARGET_O_LARGEFILE, O_LARGEFILE, O_LARGEFILE, },
#endif
{ 0, 0, 0, 0 }
};

_syscall2(int, sys_getcwd1, char *, buf, size_t, size)
Expand Down Expand Up @@ -5813,7 +5812,6 @@ static const bitmask_transtbl iflag_tbl[] = {
{ TARGET_IXOFF, TARGET_IXOFF, IXOFF, IXOFF },
{ TARGET_IMAXBEL, TARGET_IMAXBEL, IMAXBEL, IMAXBEL },
{ TARGET_IUTF8, TARGET_IUTF8, IUTF8, IUTF8},
{ 0, 0, 0, 0 }
};

static const bitmask_transtbl oflag_tbl[] = {
Expand Down Expand Up @@ -5841,7 +5839,6 @@ static const bitmask_transtbl oflag_tbl[] = {
{ TARGET_VTDLY, TARGET_VT1, VTDLY, VT1 },
{ TARGET_FFDLY, TARGET_FF0, FFDLY, FF0 },
{ TARGET_FFDLY, TARGET_FF1, FFDLY, FF1 },
{ 0, 0, 0, 0 }
};

static const bitmask_transtbl cflag_tbl[] = {
Expand Down Expand Up @@ -5876,7 +5873,6 @@ static const bitmask_transtbl cflag_tbl[] = {
{ TARGET_HUPCL, TARGET_HUPCL, HUPCL, HUPCL },
{ TARGET_CLOCAL, TARGET_CLOCAL, CLOCAL, CLOCAL },
{ TARGET_CRTSCTS, TARGET_CRTSCTS, CRTSCTS, CRTSCTS },
{ 0, 0, 0, 0 }
};

static const bitmask_transtbl lflag_tbl[] = {
Expand All @@ -5896,7 +5892,6 @@ static const bitmask_transtbl lflag_tbl[] = {
{ TARGET_PENDIN, TARGET_PENDIN, PENDIN, PENDIN },
{ TARGET_IEXTEN, TARGET_IEXTEN, IEXTEN, IEXTEN },
{ TARGET_EXTPROC, TARGET_EXTPROC, EXTPROC, EXTPROC},
{ 0, 0, 0, 0 }
};

static void target_to_host_termios (void *dst, const void *src)
Expand Down Expand Up @@ -6008,7 +6003,6 @@ static const bitmask_transtbl mmap_flags_tbl[] = {
MAP_FIXED_NOREPLACE, MAP_FIXED_NOREPLACE },
{ TARGET_MAP_UNINITIALIZED, TARGET_MAP_UNINITIALIZED,
MAP_UNINITIALIZED, MAP_UNINITIALIZED },
{ 0, 0, 0, 0 }
};

/*
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24 changes: 12 additions & 12 deletions linux-user/thunk.c
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Original file line number Diff line number Diff line change
Expand Up @@ -436,29 +436,29 @@ const argtype *thunk_print(void *arg, const argtype *type_ptr)
/* Utility function: Table-driven functions to translate bitmasks
* between host and target formats
*/
unsigned int target_to_host_bitmask(unsigned int target_mask,
const bitmask_transtbl * trans_tbl)
unsigned int target_to_host_bitmask_len(unsigned int target_mask,
const bitmask_transtbl *tbl,
size_t len)
{
const bitmask_transtbl *btp;
unsigned int host_mask = 0;

for (btp = trans_tbl; btp->target_mask && btp->host_mask; btp++) {
if ((target_mask & btp->target_mask) == btp->target_bits) {
host_mask |= btp->host_bits;
for (size_t i = 0; i < len; ++i) {
if ((target_mask & tbl[i].target_mask) == tbl[i].target_bits) {
host_mask |= tbl[i].host_bits;
}
}
return host_mask;
}

unsigned int host_to_target_bitmask(unsigned int host_mask,
const bitmask_transtbl * trans_tbl)
unsigned int host_to_target_bitmask_len(unsigned int host_mask,
const bitmask_transtbl *tbl,
size_t len)
{
const bitmask_transtbl *btp;
unsigned int target_mask = 0;

for (btp = trans_tbl; btp->target_mask && btp->host_mask; btp++) {
if ((host_mask & btp->host_mask) == btp->host_bits) {
target_mask |= btp->target_bits;
for (size_t i = 0; i < len; ++i) {
if ((host_mask & tbl[i].host_mask) == tbl[i].host_bits) {
target_mask |= tbl[i].target_bits;
}
}
return target_mask;
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