diff options
Diffstat (limited to 'sysdeps/unix/sysv/linux/i386/sysdep.h')
| -rw-r--r-- | sysdeps/unix/sysv/linux/i386/sysdep.h | 25 |
1 files changed, 18 insertions, 7 deletions
diff --git a/sysdeps/unix/sysv/linux/i386/sysdep.h b/sysdeps/unix/sysv/linux/i386/sysdep.h index 1bf20bd718..b00c976351 100644 --- a/sysdeps/unix/sysv/linux/i386/sysdep.h +++ b/sysdeps/unix/sysv/linux/i386/sysdep.h @@ -37,16 +37,25 @@ Cambridge, MA 02139, USA. */ #ifdef ASSEMBLER -/* Linux uses a negative return value to indicate syscall errors, unlike - most Unices, which use the condition codes' carry flag. */ +/* Linux uses a negative return value to indicate syscall errors, + unlike most Unices, which use the condition codes' carry flag. + + Since version 2.1 the return value of a system call might be + negative even if the call succeeded. E.g., the `lseek' system call + might return a large offset. Therefore we must not anymore test + for < 0, but test for a real error by making sure the value in %eax + is a real error number. For now (as of 2.1.1) 122 is the largest + defined error number. Given a bit room for development, Linus + chose in <asm/unistd.h> to use the values -125 to -1 for error + values. We follow him here. */ #undef PSEUDO #define PSEUDO(name, syscall_name, args) \ .text; \ SYSCALL_ERROR_HANDLER \ ENTRY (name) \ DO_CALL (args, syscall_name); \ - testl %eax, %eax; \ - jl syscall_error; + cmpl $-125, %eax; \ + jae syscall_error; #ifndef PIC #define SYSCALL_ERROR_HANDLER /* Nothing here; code in sysdep.S is used. */ @@ -70,9 +79,10 @@ syscall_error: \ popl %ebx; \ movl %ecx, (%eax); \ movl $-1, %eax; \ - ret; + ret; \ + .size syscall_error,.-syscall-error; /* A quick note: it is assumed that the call to `__errno_location' does - not modify the parameter value! */ + not modify the stack! */ #else #define SYSCALL_ERROR_HANDLER \ .type syscall_error,@function; \ @@ -85,7 +95,8 @@ syscall_error: \ movl errno@GOT(%ecx), %ecx; \ movl %edx, (%ecx); \ movl $-1, %eax; \ - ret; + ret; \ + .size syscall_error,.-syscall-error; #endif /* _LIBC_REENTRANT */ #endif /* PIC */ |