[PATCH 6/6] UML - Error handling fixes

From: Jeff Dike
Date: Fri Apr 28 2006 - 13:02:13 EST


Blairsorblade noticed some confusion between our use of a system
call's return value and errno. This patch fixes a number of related
bugs -
using errno instead of a return value
using a return value instead of errno
forgetting to negate a error return to get a positive error code

Signed-off-by: Jeff Dike <jdike@xxxxxxxxxxx>

Index: linux-2.6.16/arch/um/os-Linux/file.c
===================================================================
--- linux-2.6.16.orig/arch/um/os-Linux/file.c 2006-04-27 20:53:08.000000000 -0400
+++ linux-2.6.16/arch/um/os-Linux/file.c 2006-04-27 20:57:20.000000000 -0400
@@ -171,7 +171,7 @@ int os_sigio_async(int master, int slave

flags = fcntl(master, F_GETFL);
if(flags < 0)
- return errno;
+ return -errno;

if((fcntl(master, F_SETFL, flags | O_NONBLOCK | O_ASYNC) < 0) ||
(fcntl(master, F_SETOWN, os_getpid()) < 0))
Index: linux-2.6.16/arch/um/os-Linux/skas/process.c
===================================================================
--- linux-2.6.16.orig/arch/um/os-Linux/skas/process.c 2006-04-27 20:53:08.000000000 -0400
+++ linux-2.6.16/arch/um/os-Linux/skas/process.c 2006-04-27 20:57:20.000000000 -0400
@@ -344,12 +344,12 @@ int copy_context_skas0(unsigned long new
err = ptrace_setregs(pid, regs);
if(err < 0)
panic("copy_context_skas0 : PTRACE_SETREGS failed, "
- "pid = %d, errno = %d\n", pid, errno);
+ "pid = %d, errno = %d\n", pid, -err);

err = ptrace_setfpregs(pid, fp_regs);
if(err < 0)
panic("copy_context_skas0 : PTRACE_SETFPREGS failed, "
- "pid = %d, errno = %d\n", pid, errno);
+ "pid = %d, errno = %d\n", pid, -err);

/* set a well known return code for detection of child write failure */
child_data->err = 12345678;
@@ -362,7 +362,7 @@ int copy_context_skas0(unsigned long new
pid = data->err;
if(pid < 0)
panic("copy_context_skas0 - stub-parent reports error %d\n",
- pid);
+ -pid);

/* Wait, until child has finished too: read child's result from
* child's stack and check it.
Index: linux-2.6.16/arch/um/os-Linux/sys-i386/registers.c
===================================================================
--- linux-2.6.16.orig/arch/um/os-Linux/sys-i386/registers.c 2006-04-27 20:53:42.000000000 -0400
+++ linux-2.6.16/arch/um/os-Linux/sys-i386/registers.c 2006-04-27 20:57:20.000000000 -0400
@@ -104,7 +104,7 @@ void init_registers(int pid)
err = ptrace(PTRACE_GETREGS, pid, 0, exec_regs);
if(err)
panic("check_ptrace : PTRACE_GETREGS failed, errno = %d",
- err);
+ errno);

errno = 0;
err = ptrace(PTRACE_GETFPXREGS, pid, 0, exec_fpx_regs);
@@ -119,7 +119,7 @@ void init_registers(int pid)
err = ptrace(PTRACE_GETFPREGS, pid, 0, exec_fp_regs);
if(err)
panic("check_ptrace : PTRACE_GETFPREGS failed, errno = %d",
- err);
+ errno);
}

void get_safe_registers(unsigned long *regs, unsigned long *fp_regs)
Index: linux-2.6.16/arch/um/os-Linux/sys-x86_64/registers.c
===================================================================
--- linux-2.6.16.orig/arch/um/os-Linux/sys-x86_64/registers.c 2006-04-27 20:53:42.000000000 -0400
+++ linux-2.6.16/arch/um/os-Linux/sys-x86_64/registers.c 2006-04-27 20:57:20.000000000 -0400
@@ -62,12 +62,12 @@ void init_registers(int pid)
err = ptrace(PTRACE_GETREGS, pid, 0, exec_regs);
if(err)
panic("check_ptrace : PTRACE_GETREGS failed, errno = %d",
- err);
+ errno);

err = ptrace(PTRACE_GETFPREGS, pid, 0, exec_fp_regs);
if(err)
panic("check_ptrace : PTRACE_GETFPREGS failed, errno = %d",
- err);
+ errno);
}

void get_safe_registers(unsigned long *regs, unsigned long *fp_regs)
Index: linux-2.6.16/arch/um/os-Linux/umid.c
===================================================================
--- linux-2.6.16.orig/arch/um/os-Linux/umid.c 2006-04-27 20:53:08.000000000 -0400
+++ linux-2.6.16/arch/um/os-Linux/umid.c 2006-04-27 20:57:20.000000000 -0400
@@ -178,14 +178,14 @@ static void __init create_pid_file(void)
fd = open(file, O_RDWR | O_CREAT | O_EXCL, 0644);
if(fd < 0){
printk("Open of machine pid file \"%s\" failed: %s\n",
- file, strerror(-fd));
+ file, strerror(errno));
return;
}

snprintf(pid, sizeof(pid), "%d\n", getpid());
n = write(fd, pid, strlen(pid));
if(n != strlen(pid))
- printk("Write of pid file failed - err = %d\n", -n);
+ printk("Write of pid file failed - err = %d\n", errno);

close(fd);
}

-
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