[ovs-dev] [worker 09/12] vlog: Use system calls instead of stdio to write log files.

[Ethan Jackson]

Looks good, thanks.

Ethan

On Tue, May 22, 2012 at 5:19 PM, Ben Pfaff <blp at nicira.com> wrote:
> This will be easier to deal with in an upcoming commit that will use a
> subprocess to do asynchronous log I/O.
>
> Signed-off-by: Ben Pfaff <blp at nicira.com>
> ---
>  lib/vlog.c |   24 ++++++++++++------------
>  1 files changed, 12 insertions(+), 12 deletions(-)
>
> diff --git a/lib/vlog.c b/lib/vlog.c
> index fdc1b17..f7030b9 100644
> --- a/lib/vlog.c
> +++ b/lib/vlog.c
> @@ -19,6 +19,7 @@
>  #include <assert.h>
>  #include <ctype.h>
>  #include <errno.h>
> +#include <fcntl.h>
>  #include <stdarg.h>
>  #include <stdlib.h>
>  #include <string.h>
> @@ -84,7 +85,7 @@ static struct facility facilities[VLF_N_FACILITIES] = {
>
>  /* VLF_FILE configuration. */
>  static char *log_file_name;
> -static FILE *log_file;
> +static int log_fd = -1;
>
>  /* vlog initialized? */
>  static bool vlog_inited;
> @@ -186,7 +187,7 @@ update_min_level(struct vlog_module *module)
>
>     module->min_level = VLL_OFF;
>     for (facility = 0; facility < VLF_N_FACILITIES; facility++) {
> -        if (log_file || facility != VLF_FILE) {
> +        if (log_fd >= 0 || facility != VLF_FILE) {
>             enum vlog_level level = module->levels[facility];
>             if (level > module->min_level) {
>                 module->min_level = level;
> @@ -279,10 +280,10 @@ vlog_set_log_file(const char *file_name)
>     int error;
>
>     /* Close old log file. */
> -    if (log_file) {
> +    if (log_fd >= 0) {
>         VLOG_INFO("closing log file");
> -        fclose(log_file);
> -        log_file = NULL;
> +        close(log_fd);
> +        log_fd = -1;
>     }
>
>     /* Update log file name and free old name.  The ordering is important
> @@ -296,13 +297,13 @@ vlog_set_log_file(const char *file_name)
>
>     /* Open new log file and update min_levels[] to reflect whether we actually
>      * have a log_file. */
> -    log_file = fopen(log_file_name, "a");
> +    log_fd = open(log_file_name, O_WRONLY | O_CREAT | O_APPEND, 0666);
>     for (mp = vlog_modules; mp < &vlog_modules[n_vlog_modules]; mp++) {
>         update_min_level(*mp);
>     }
>
>     /* Log success or failure. */
> -    if (!log_file) {
> +    if (log_fd < 0) {
>         VLOG_WARN("failed to open %s for logging: %s",
>                   log_file_name, strerror(errno));
>         error = errno;
> @@ -330,8 +331,8 @@ vlog_reopen_log_file(void)
>     /* Skip re-opening if it would be a no-op because the old and new files are
>      * the same.  (This avoids writing "closing log file" followed immediately
>      * by "opened log file".) */
> -    if (log_file
> -        && !fstat(fileno(log_file), &old)
> +    if (log_fd >= 0
> +        && !fstat(log_fd, &old)
>         && !stat(log_file_name, &new)
>         && old.st_dev == new.st_dev
>         && old.st_ino == new.st_ino) {
> @@ -682,7 +683,7 @@ vlog_valist(const struct vlog_module *module, enum vlog_level level,
>  {
>     bool log_to_console = module->levels[VLF_CONSOLE] >= level;
>     bool log_to_syslog = module->levels[VLF_SYSLOG] >= level;
> -    bool log_to_file = module->levels[VLF_FILE] >= level && log_file;
> +    bool log_to_file = module->levels[VLF_FILE] >= level && log_fd >= 0;
>     if (log_to_console || log_to_syslog || log_to_file) {
>         int save_errno = errno;
>         static unsigned int msg_num;
> @@ -718,8 +719,7 @@ vlog_valist(const struct vlog_module *module, enum vlog_level level,
>             format_log_message(module, level, VLF_FILE, msg_num,
>                                message, args, &s);
>             ds_put_char(&s, '\n');
> -            fputs(ds_cstr(&s), log_file);
> -            fflush(log_file);
> +            write(log_fd, s.string, s.length);
>         }
>
>         ds_destroy(&s);
> --
> 1.7.2.5
>
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