From af861deaed5aa979522ec72425913295dc050f10 Mon Sep 17 00:00:00 2001 From: Filip Bozuta Date: Fri, 19 Jun 2020 14:33:29 +0200 Subject: [PATCH] linux-user: Add strace support for printing arguments of lseek() This patch implements strace argument printing functionality for syscall: *lseek - reposition read/write file offset off_t lseek(int fd, off_t offset, int whence) man page: https://www.man7.org/linux/man-pages/man2/lseek.2.html Implementation notes: The syscall's third argument "whence" has predefined values: "SEEK_SET","SEEK_CUR","SEEK_END","SEEK_DATA","SEEK_HOLE" and thus a separate printing function "print_lseek" was stated in file "strace.list". This function is defined in "strace.c" by using an existing function "print_raw_param()" to print the first and second argument and a switch(case) statement for the predefined values of the third argument. Values "SEEK_DATA" and "SEEK_HOLE" are defined in kernel version 3.1. That is the reason why case statements for these values are enwrapped in #ifdef directive. Signed-off-by: Filip Bozuta Reviewed-by: Laurent Vivier Message-Id: <20200619123331.17387-5-filip.bozuta@syrmia.com> Signed-off-by: Laurent Vivier --- linux-user/strace.c | 31 +++++++++++++++++++++++++++++++ linux-user/strace.list | 2 +- 2 files changed, 32 insertions(+), 1 deletion(-) diff --git a/linux-user/strace.c b/linux-user/strace.c index 760020132b..a26736516b 100644 --- a/linux-user/strace.c +++ b/linux-user/strace.c @@ -1833,6 +1833,37 @@ print__llseek(const struct syscallname *name, } #endif +#ifdef TARGET_NR_lseek +static void +print_lseek(const struct syscallname *name, + abi_long arg0, abi_long arg1, abi_long arg2, + abi_long arg3, abi_long arg4, abi_long arg5) +{ + print_syscall_prologue(name); + print_raw_param("%d", arg0, 0); + print_raw_param(TARGET_ABI_FMT_ld, arg1, 0); + switch (arg2) { + case SEEK_SET: + qemu_log("SEEK_SET"); break; + case SEEK_CUR: + qemu_log("SEEK_CUR"); break; + case SEEK_END: + qemu_log("SEEK_END"); break; +#ifdef SEEK_DATA + case SEEK_DATA: + qemu_log("SEEK_DATA"); break; +#endif +#ifdef SEEK_HOLE + case SEEK_HOLE: + qemu_log("SEEK_HOLE"); break; +#endif + default: + print_raw_param("%#x", arg2, 1); + } + print_syscall_epilogue(name); +} +#endif + #if defined(TARGET_NR_socket) static void print_socket(const struct syscallname *name, diff --git a/linux-user/strace.list b/linux-user/strace.list index d04ad507b0..a4a8c61969 100644 --- a/linux-user/strace.list +++ b/linux-user/strace.list @@ -516,7 +516,7 @@ { TARGET_NR_lremovexattr, "lremovexattr" , NULL, print_lremovexattr, NULL }, #endif #ifdef TARGET_NR_lseek -{ TARGET_NR_lseek, "lseek" , NULL, NULL, NULL }, +{ TARGET_NR_lseek, "lseek" , NULL, print_lseek, NULL }, #endif #ifdef TARGET_NR_lsetxattr { TARGET_NR_lsetxattr, "lsetxattr" , NULL, NULL, NULL },