[lxc-devel] [PATCH 1/1] lxc_info: flush stdout before calling routines which may fork

[Tycho Andersen]

On Wed, Nov 12, 2014 at 03:51:04AM +0000, Serge Hallyn wrote:
> Otherwise both resulting takss will print what they had flushed when they
> exit.
> 
> This fixes https://bugs.launchpad.net/bugs/1389244
> 
> Signed-off-by: Serge Hallyn <serge.hallyn at ubuntu.com>

Tested-by: Tycho Andersen <tycho.andersen at canonical.com>

Thanks!

> ---
>  src/lxc/lxc_info.c | 10 ++++++++++
>  1 file changed, 10 insertions(+)
> 
> diff --git a/src/lxc/lxc_info.c b/src/lxc/lxc_info.c
> index e1e39c0..b360aa8 100644
> --- a/src/lxc/lxc_info.c
> +++ b/src/lxc/lxc_info.c
> @@ -169,6 +169,7 @@ static void print_net_stats(struct lxc_container *c)
>  		if (!ifname)
>  			return;
>  		printf("%-15s %s\n", "Link:", ifname);
> +		fflush(stdout);
>  
>  		/* XXX: tx and rx are reversed from the host vs container
>  		 * perspective, print them from the container perspective
> @@ -179,6 +180,7 @@ static void print_net_stats(struct lxc_container *c)
>  			str_chomp(buf);
>  			rx_bytes = str_size_humanize(buf, sizeof(buf));
>  			printf("%-15s %s\n", " TX bytes:", buf);
> +			fflush(stdout);
>  		}
>  
>  		snprintf(path, sizeof(path), "/sys/class/net/%s/statistics/tx_bytes", ifname);
> @@ -187,11 +189,13 @@ static void print_net_stats(struct lxc_container *c)
>  			str_chomp(buf);
>  			tx_bytes = str_size_humanize(buf, sizeof(buf));
>  			printf("%-15s %s\n", " RX bytes:", buf);
> +			fflush(stdout);
>  		}
>  
>  		sprintf(buf, "%llu", rx_bytes + tx_bytes);
>  		str_size_humanize(buf, sizeof(buf));
>  		printf("%-15s %s\n", " Total bytes:", buf);
> +		fflush(stdout);
>  		free(ifname);
>  	}
>  }
> @@ -210,6 +214,7 @@ static void print_stats(struct lxc_container *c)
>  		} else {
>  			printf("%-15s %s\n", "CPU use:", buf);
>  		}
> +		fflush(stdout);
>  	}
>  
>  	ret = c->get_cgroup_item(c, "blkio.throttle.io_service_bytes", buf, sizeof(buf));
> @@ -229,6 +234,7 @@ static void print_stats(struct lxc_container *c)
>  			str_size_humanize(buf, sizeof(buf));
>  			printf("%-15s %s\n", "BlkIO use:", buf);
>  		}
> +		fflush(stdout);
>  	}
>  
>  	static const struct {
> @@ -246,6 +252,7 @@ static void print_stats(struct lxc_container *c)
>  			str_chomp(buf);
>  			str_size_humanize(buf, sizeof(buf));
>  			printf("%-15s %s\n", lxstat[i].name, buf);
> +			fflush(stdout);
>  		}
>  	}
>  }
> @@ -260,6 +267,7 @@ static void print_info_msg_int(const char *key, int value)
>  		else
>  			printf("%-15s %d\n", key, value);
>  	}
> +	fflush(stdout);
>  }
>  
>  static void print_info_msg_str(const char *key, const char *value)
> @@ -272,6 +280,7 @@ static void print_info_msg_str(const char *key, const char *value)
>  		else
>  			printf("%-15s %s\n", key, value);
>  	}
> +	fflush(stdout);
>  }
>  
>  static int print_info(const char *name, const char *lxcpath)
> @@ -359,6 +368,7 @@ static int print_info(const char *name, const char *lxcpath)
>  		} else {
>  			fprintf(stderr, "%s invalid\n", key[i]);
>  		}
> +		fflush(stdout);
>  	}
>  
>  	lxc_container_put(c);
> -- 
> 2.1.0
> 
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