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libgloss/arm: monitor_stderr [PATCH]
- From: Shaun Jackman <sjackman at gmail dot com>
- To: newlib at sources dot redhat dot com
- Date: Thu, 4 Aug 2005 11:39:16 -0600
- Subject: libgloss/arm: monitor_stderr [PATCH]
- Reply-to: Shaun Jackman <sjackman at gmail dot com>
libgloss for ARM remaps user space file descriptors to ARM kernel
space file descriptors to support descriptors 0, 1, and 2 being their
usual stdin, stdout, and stderr. monitor_stdin is set to the result of
SWI_open(":tt", "r") and monitor_stdout is set to the result of
SWI_open(":tt", "w"). monitor_stderr is set to the same value as
monitor_stdout. This results in libgloss mapping both descriptors 1
and 2 to the same value, making it impossible for the kernel to
distinguish the two.
A patch I've been using and sitting on for a while sets monitor_stderr
to the result of SWI_open(":tt", "a"). Since "a" is a write mode like
"w", most ARM kernels should act sensibly, I'm hoping. The GDB
simulator, for example, returns 1 for both "w" and "a", so it behaves
exactly the same with this patch as without. However, a kernel in the
know can now return 1 for "w" and 2 for "a".
If someone knows of an ARM kernel that does *not* work with this
patch, I'd like to know how the kernel responds to the
SWI_open(":tt", "a") call so that I can work around it.
Cheers,
Shaun
2005-08-04 Shaun Jackman <sjackman@gmail.com>
* libgloss/syscalls.c (initialise_monitor_handles): Set
monitor_stdout to the result of SWI_open(":tt", "a")
instead of simply duplicating stdout.
Index: syscalls.c
===================================================================
RCS file: /cvs/src/src/libgloss/arm/syscalls.c,v
retrieving revision 1.5
diff -u -r1.5 syscalls.c
--- syscalls.c 18 Jul 2005 16:18:17 -0000 1.5
+++ syscalls.c 4 Aug 2005 17:18:22 -0000
@@ -145,7 +145,12 @@
block[0] = (int) ":tt";
block[2] = 3; /* length of filename */
block[1] = 4; /* mode "w" */
- monitor_stdout = monitor_stderr = do_AngelSWI
(AngelSWI_Reason_Open, (void *) block);
+ monitor_stdout = do_AngelSWI (AngelSWI_Reason_Open, (void *) block);
+
+ block[0] = (int) ":tt";
+ block[2] = 3; /* length of filename */
+ block[1] = 8; /* mode "a" */
+ monitor_stderr = do_AngelSWI (AngelSWI_Reason_Open, (void *) block);
#else
int fh;
const char * name;
@@ -162,7 +167,14 @@
: "=r"(fh)
: "i" (SWI_Open),"r"(name)
: "r0","r1");
- monitor_stdout = monitor_stderr = fh;
+ monitor_stdout = fh;
+
+ name = ":tt";
+ asm ("mov r0,%2; mov r1, #8; swi %a1; mov %0, r0"
+ : "=r"(fh)
+ : "i" (SWI_Open),"r"(name)
+ : "r0","r1");
+ monitor_stderr = fh;
#endif
for (i = 0; i < MAX_OPEN_FILES; i ++)
@@ -172,6 +184,8 @@
openfiles[0].pos = 0;
openfiles[1].handle = monitor_stdout;
openfiles[1].pos = 0;
+ openfiles[2].handle = monitor_stderr;
+ openfiles[2].pos = 0;
}
static int
2005-08-04 Shaun Jackman <sjackman@gmail.com>
* libgloss/syscalls.c (initialise_monitor_handles): Set
monitor_stdout to the result of SWI_open(":tt", "a")
instead of simply duplicating stdout.
Index: syscalls.c
===================================================================
RCS file: /cvs/src/src/libgloss/arm/syscalls.c,v
retrieving revision 1.5
diff -u -r1.5 syscalls.c
--- syscalls.c 18 Jul 2005 16:18:17 -0000 1.5
+++ syscalls.c 4 Aug 2005 17:18:22 -0000
@@ -145,7 +145,12 @@
block[0] = (int) ":tt";
block[2] = 3; /* length of filename */
block[1] = 4; /* mode "w" */
- monitor_stdout = monitor_stderr = do_AngelSWI (AngelSWI_Reason_Open, (void *) block);
+ monitor_stdout = do_AngelSWI (AngelSWI_Reason_Open, (void *) block);
+
+ block[0] = (int) ":tt";
+ block[2] = 3; /* length of filename */
+ block[1] = 8; /* mode "a" */
+ monitor_stderr = do_AngelSWI (AngelSWI_Reason_Open, (void *) block);
#else
int fh;
const char * name;
@@ -162,7 +167,14 @@
: "=r"(fh)
: "i" (SWI_Open),"r"(name)
: "r0","r1");
- monitor_stdout = monitor_stderr = fh;
+ monitor_stdout = fh;
+
+ name = ":tt";
+ asm ("mov r0,%2; mov r1, #8; swi %a1; mov %0, r0"
+ : "=r"(fh)
+ : "i" (SWI_Open),"r"(name)
+ : "r0","r1");
+ monitor_stderr = fh;
#endif
for (i = 0; i < MAX_OPEN_FILES; i ++)
@@ -172,6 +184,8 @@
openfiles[0].pos = 0;
openfiles[1].handle = monitor_stdout;
openfiles[1].pos = 0;
+ openfiles[2].handle = monitor_stderr;
+ openfiles[2].pos = 0;
}
static int