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[PATCH 3/5] linux-user: Add strace support for printing arguments of lse
From: |
Filip Bozuta |
Subject: |
[PATCH 3/5] linux-user: Add strace support for printing arguments of lseek() |
Date: |
Tue, 2 Jun 2020 13:53:29 +0200 |
From: Filip Bozuta <Filip.Bozuta@syrmia.com>
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 <Filip.Bozuta@syrmia.com>
---
linux-user/strace.c | 32 ++++++++++++++++++++++++++++++++
linux-user/strace.list | 2 +-
2 files changed, 33 insertions(+), 1 deletion(-)
diff --git a/linux-user/strace.c b/linux-user/strace.c
index 5cf419989c..b7f012f1b5 100644
--- a/linux-user/strace.c
+++ b/linux-user/strace.c
@@ -1768,6 +1768,38 @@ 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("%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);
+ qemu_log(" /* SEEK_??? */");
+ }
+ 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 8d51c54bca..5a56212532 100644
--- a/linux-user/strace.list
+++ b/linux-user/strace.list
@@ -513,7 +513,7 @@
{ TARGET_NR_lremovexattr, "lremovexattr" , NULL, NULL, 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 },
--
2.17.1
- [PATCH 0/5] Add strace support for printing arguments of selected syscalls, Filip Bozuta, 2020/06/02
- [PATCH 2/5] linux-user: Add strace support for printing argument of syscalls used for extend attributes, Filip Bozuta, 2020/06/02
- [PATCH 1/5] linux-user: Add strace support for a group of syscalls, Filip Bozuta, 2020/06/02
- [PATCH 4/5] linux-user: Add strace support for printing arguments of chown()/lchown(), Filip Bozuta, 2020/06/02
- [PATCH 5/5] linux-user: Add strace support for printing arguments of fallocate(), Filip Bozuta, 2020/06/02
- [PATCH 3/5] linux-user: Add strace support for printing arguments of lseek(),
Filip Bozuta <=
- Re: [PATCH 0/5] Add strace support for printing arguments of selected syscalls, no-reply, 2020/06/02
- Re: [PATCH 0/5] Add strace support for printing arguments of selected syscalls, Alex Bennée, 2020/06/03