From 888468db949e8ea1641c33d97e70b70f57eb69e9 Mon Sep 17 00:00:00 2001 From: Filip Bozuta Date: Thu, 23 Jul 2020 23:02:33 +0200 Subject: linux-user: Add strace support for printing arguments for ioctls used for terminals and serial lines Functions "print_ioctl()" and "print_syscall_ret_ioctl()" are used to print arguments of "ioctl()" with "-strace". These functions use "thunk_print()", which is defined in "thunk.c", to print the contents of ioctl's third arguments that are not basic types. However, this function doesn't handle ioctls of group ioctl_tty which are used for terminals and serial lines. These ioctls use a type "struct termios" which thunk type is defined in a non standard way using "STRUCT_SPECIAL()". This means that this type is not decoded regularly using "thunk_convert()" and uses special converting functions "target_to_host_termios()" and "host_to_target_termios()", which are defined in "syscall.c" to decode it's values. For simillar reasons, this type is also not printed regularly using "thunk_print()". That is the reason why a separate printing function "print_termios()" is defined in file "strace.c". This function decodes and prints flag values of the "termios" structure. Implementation notes: Function "print_termios()" was implemented in "strace.c" using an existing function "print_flags()" to print flag values of "struct termios" fields. Also, recently implemented function "print_enums()" was also used to print enumareted values which are contained in the fields of 'struct termios'. These flag values were defined using an existing macro "FLAG_TARGET()" that generates aproppriate target flag values and string representations of these flags. Also, the recently defined macro "ENUM_TARGET()" was used to generate aproppriate enumarated values and their respective string representations. Function "print_termios()" was declared in "qemu.h" so that it can be accessed in "syscall.c". Type "StructEntry" defined in "exec/user/thunk.h" contains information that is used to decode structure values. Field "void print(void *arg)" was added in this structure as a special print function. Also, function "thunk_print()" was changed a little so that it uses this special print function in case it is defined. This printing function was instantiated with the defined "print_termios()" in "syscall.c" in "struct_termios_def". Signed-off-by: Filip Bozuta Reviewed-by: Laurent Vivier Message-Id: <20200723210233.349690-4-Filip.Bozuta@syrmia.com> Signed-off-by: Laurent Vivier --- include/exec/user/thunk.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/exec/user') diff --git a/include/exec/user/thunk.h b/include/exec/user/thunk.h index 7992475..a5bbb2c 100644 --- a/include/exec/user/thunk.h +++ b/include/exec/user/thunk.h @@ -55,6 +55,7 @@ typedef struct { int *field_offsets[2]; /* special handling */ void (*convert[2])(void *dst, const void *src); + void (*print)(void *arg); int size[2]; int align[2]; const char *name; -- cgit v1.1