Messages in this thread Patch in this message | | | From | Denys Vlasenko <> | Subject | [PATCH 2/2] ptrace: simplify PTRACE_foo constants and PTRACE_SETOPTIONS code | Date | Fri, 9 Sep 2011 08:29:34 +0200 |
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ptrace: simplify PTRACE_foo constants and PTRACE_SETOPTIONS code
Exchange PT_TRACESYSGOOD and PT_PTRACE_CAP bit positions, which makes PT_option bits contiguous and therefore makes code in ptrace_setoptions() much simpler.
Every PTRACE_O_TRACEevent is defined to (1 << PTRACE_EVENT_event) instead of using explicit numeric constants, to ensure we don't mess up relationship between bit positions and event ids.
PT_EVENT_FLAG_SHIFT was not particularly useful, PT_OPT_FLAG_SHIFT with value of PT_EVENT_FLAG_SHIFT-1 is easier to use.
PT_TRACE_MASK constant is nuked, the only its use is replaced by (PTRACE_O_MASK << PT_OPT_FLAG_SHIFT).
Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com> ---
diff --git a/include/linux/ptrace.h b/include/linux/ptrace.h index 800f113..0911100 100644 --- a/include/linux/ptrace.h +++ b/include/linux/ptrace.h @@ -54,17 +54,6 @@ /* flags in @data for PTRACE_SEIZE */ #define PTRACE_SEIZE_DEVEL 0x80000000 /* temp flag for development */ -/* options set using PTRACE_SETOPTIONS */ -#define PTRACE_O_TRACESYSGOOD 0x00000001 -#define PTRACE_O_TRACEFORK 0x00000002 -#define PTRACE_O_TRACEVFORK 0x00000004 -#define PTRACE_O_TRACECLONE 0x00000008 -#define PTRACE_O_TRACEEXEC 0x00000010 -#define PTRACE_O_TRACEVFORKDONE 0x00000020 -#define PTRACE_O_TRACEEXIT 0x00000040 - -#define PTRACE_O_MASK 0x0000007f - /* Wait extended result codes for the above trace options. */ #define PTRACE_EVENT_FORK 1 #define PTRACE_EVENT_VFORK 2 @@ -74,6 +63,17 @@ #define PTRACE_EVENT_EXIT 6 #define PTRACE_EVENT_STOP 7 +/* options set using PTRACE_SETOPTIONS */ +#define PTRACE_O_TRACESYSGOOD 1 +#define PTRACE_O_TRACEFORK (1 << PTRACE_EVENT_FORK) +#define PTRACE_O_TRACEVFORK (1 << PTRACE_EVENT_VFORK) +#define PTRACE_O_TRACECLONE (1 << PTRACE_EVENT_CLONE) +#define PTRACE_O_TRACEEXEC (1 << PTRACE_EVENT_EXEC) +#define PTRACE_O_TRACEVFORKDONE (1 << PTRACE_EVENT_VFORK_DONE) +#define PTRACE_O_TRACEEXIT (1 << PTRACE_EVENT_EXIT) + +#define PTRACE_O_MASK 0x0000007f + #include <asm/ptrace.h> #ifdef __KERNEL__ @@ -88,13 +88,12 @@ #define PT_SEIZED 0x00010000 /* SEIZE used, enable new behavior */ #define PT_PTRACED 0x00000001 #define PT_DTRACE 0x00000002 /* delayed trace (used on m68k, i386) */ -#define PT_TRACESYSGOOD 0x00000004 -#define PT_PTRACE_CAP 0x00000008 /* ptracer can follow suid-exec */ +#define PT_PTRACE_CAP 0x00000004 /* ptracer can follow suid-exec */ +#define PT_OPT_FLAG_SHIFT 3 /* PT_TRACE_* event enable flags */ -#define PT_EVENT_FLAG_SHIFT 4 -#define PT_EVENT_FLAG(event) (1 << (PT_EVENT_FLAG_SHIFT + (event) - 1)) - +#define PT_EVENT_FLAG(event) (1 << (PT_OPT_FLAG_SHIFT + (event))) +#define PT_TRACESYSGOOD PT_EVENT_FLAG(0) #define PT_TRACE_FORK PT_EVENT_FLAG(PTRACE_EVENT_FORK) #define PT_TRACE_VFORK PT_EVENT_FLAG(PTRACE_EVENT_VFORK) #define PT_TRACE_CLONE PT_EVENT_FLAG(PTRACE_EVENT_CLONE) @@ -102,8 +101,6 @@ #define PT_TRACE_VFORK_DONE PT_EVENT_FLAG(PTRACE_EVENT_VFORK_DONE) #define PT_TRACE_EXIT PT_EVENT_FLAG(PTRACE_EVENT_EXIT) -#define PT_TRACE_MASK 0x000003f4 - /* single stepping state bits (used on ARM and PA-RISC) */ #define PT_SINGLESTEP_BIT 31 #define PT_SINGLESTEP (1<<PT_SINGLESTEP_BIT) diff --git a/kernel/ptrace.c b/kernel/ptrace.c index 02df3c1..6664923 100644 --- a/kernel/ptrace.c +++ b/kernel/ptrace.c @@ -243,7 +243,7 @@ static int ptrace_attach(struct task_struct *task, long request, /* * Protect exec's credential calculations against our interference; - * interference; SUID, SGID and LSM creds get determined differently + * SUID, SGID and LSM creds get determined differently * under ptrace. */ retval = -ERESTARTNOINTR; @@ -509,31 +509,16 @@ int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long ds static int ptrace_setoptions(struct task_struct *child, unsigned long data) { + unsigned flags; + if (data & ~(unsigned long)PTRACE_O_MASK) return -EINVAL; - child->ptrace &= ~PT_TRACE_MASK; - - if (data & PTRACE_O_TRACESYSGOOD) - child->ptrace |= PT_TRACESYSGOOD; - - if (data & PTRACE_O_TRACEFORK) - child->ptrace |= PT_TRACE_FORK; - - if (data & PTRACE_O_TRACEVFORK) - child->ptrace |= PT_TRACE_VFORK; - - if (data & PTRACE_O_TRACECLONE) - child->ptrace |= PT_TRACE_CLONE; - - if (data & PTRACE_O_TRACEEXEC) - child->ptrace |= PT_TRACE_EXEC; - - if (data & PTRACE_O_TRACEVFORKDONE) - child->ptrace |= PT_TRACE_VFORK_DONE; - - if (data & PTRACE_O_TRACEEXIT) - child->ptrace |= PT_TRACE_EXIT; + /* Avoid intermediate state when all opts are cleared */ + flags = child->ptrace; + flags &= ~(PTRACE_O_MASK << PT_OPT_FLAG_SHIFT); + flags |= (data << PT_OPT_FLAG_SHIFT); + child->ptrace = flags; return 0; }
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