Messages in this thread |  | | Date | Thu, 22 Nov 2001 08:36:23 -0600 | From | Phil Howard <> | Subject | EINTR vs ERESTARTSYS, ERESTARTSYS not defined |
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The accept() call does indeed return errno==ERESTARTSYS to user space when coming back from signal handling, even though other things like poll() return errno==EINTR. This would not really be a problem except for this in include/linux/errno.h starting at line 6:
+============================================================================= | #ifdef __KERNEL__ | | /* Should never be seen by user programs */ | #define ERESTARTSYS 512 | #define ERESTARTNOINTR 513 | #define ERESTARTNOHAND 514 /* restart if no handler.. */ | #define ENOIOCTLCMD 515 /* No ioctl command */ +=============================================================================
So which way is it _supposed_ to be (so someone can patch things up to make it consistent):
1. User space should never see ERESTARTSYS from any system call
2. ERESTARTSYS can be seen from system call and is defined somewhere
In user space I have to define __KERNEL__ to get programs to compile when coded to know about all possible (valid?) values of errno from system calls. As seen from strace:
+============================================================================= | [pid 6453] accept(5, 0xbffff908, [16]) = ? ERESTARTSYS (To be restarted) | [pid 6453] --- SIGALRM (Alarm clock) --- | [pid 6453] getppid() = 6452 | [pid 6453] gettimeofday({1006439405, 5879}, NULL) = 0 | [pid 6453] setitimer(ITIMER_REAL, {it_interval={0, 0}, it_value={9, 994121}}, NULL) = 0 | [pid 6453] rt_sigreturn(0x5) = -1 EINTR (Interrupted system call) | [pid 6453] accept(5, 0xbffff908, [16]) = ? ERESTARTSYS (To be restarted) | [pid 6453] --- SIGALRM (Alarm clock) --- | [pid 6453] getppid() = 6452 | [pid 6453] gettimeofday({1006439415, 6422}, NULL) = 0 | [pid 6453] setitimer(ITIMER_REAL, {it_interval={0, 0}, it_value={9, 993578}}, NULL) = 0 | [pid 6453] rt_sigreturn(0x5) = -1 EINTR (Interrupted system call) | [pid 6453] accept(5, 0xbffff908, [16]) = ? ERESTARTSYS (To be restarted) +=============================================================================
-- ----------------------------------------------------------------- | Phil Howard - KA9WGN | Dallas | http://linuxhomepage.com/ | | phil-nospam@ipal.net | Texas, USA | http://phil.ipal.org/ | ----------------------------------------------------------------- - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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