58cfa6c2e6
Bring linux-user write(2) handling into line with linux for the case of a 0-byte write with a NULL buffer. Based on a patch originally written by Zhuowei Zhang. Addresses https://bugs.launchpad.net/qemu/+bug/1716292. >From Zhuowei Zhang's patch (https://lists.gnu.org/archive/html/qemu-devel/2017-09/msg08073.html): Linux returns success for the special case of calling write with a zero-length NULL buffer: compiling and running int main() { ssize_t ret = write(STDOUT_FILENO, NULL, 0); fprintf(stderr, "write returned %ld\n", ret); return 0; } gives "write returned 0" when run directly, but "write returned -1" in QEMU. This commit checks for this situation and returns success if found. Subsequent discussion raised the following questions (and my answers): - Q. Should TARGET_NR_read pass through to safe_read in this situation too? A. I'm wary of changing unrelated code to the specific problem I'm addressing. TARGET_NR_read is already consistent with Linux for this case. - Q. Do pread64/pwrite64 need to be changed similarly? A. Experiment suggests not: both linux and linux-user yield -1 for NULL 0-length reads/writes. Signed-off-by: Tony Garnock-Jones <tonygarnockjones@gmail.com> Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org> Reviewed-by: Laurent Vivier <laurent@vivier.eu> Message-Id: <20180908182205.GB409@mornington.dcs.gla.ac.uk> Signed-off-by: Laurent Vivier <laurent@vivier.eu> |
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| aarch64 | ||
| alpha | ||
| arm | ||
| cris | ||
| generic | ||
| host | ||
| hppa | ||
| i386 | ||
| m68k | ||
| microblaze | ||
| mips | ||
| mips64 | ||
| nios2 | ||
| openrisc | ||
| ppc | ||
| riscv | ||
| s390x | ||
| sh4 | ||
| sparc | ||
| sparc64 | ||
| tilegx | ||
| x86_64 | ||
| xtensa | ||
| cpu_loop-common.h | ||
| elfload.c | ||
| errno_defs.h | ||
| exit.c | ||
| fd-trans.c | ||
| fd-trans.h | ||
| flat.h | ||
| flatload.c | ||
| ioctls.h | ||
| linux_loop.h | ||
| linuxload.c | ||
| m68k-sim.c | ||
| main.c | ||
| Makefile.objs | ||
| mmap.c | ||
| qemu.h | ||
| safe-syscall.S | ||
| signal-common.h | ||
| signal.c | ||
| socket.h | ||
| strace.c | ||
| strace.list | ||
| syscall_defs.h | ||
| syscall_types.h | ||
| syscall.c | ||
| target_flat.h | ||
| trace-events | ||
| uaccess.c | ||
| uname.c | ||
| uname.h | ||
| vm86.c | ||