[pulseaudio-discuss] [PATCH 1/2] Log feature:Add a new log target to a file descriptor

[Becker, VincentX]

>-----Original Message-----
>From: pulseaudio-discuss-bounces at mail.0pointer.de [mailto:pulseaudio-
>discuss-bounces at mail.0pointer.de] On Behalf Of Maarten Bosmans
>Sent: Wednesday, March 09, 2011 5:31 PM
>To: General PulseAudio Discussion
>Subject: Re: [pulseaudio-discuss] [PATCH 1/2] Log feature:Add a new log
>target to a file descriptor
>
>2011/3/9 Vincent Becker <vincentx.becker at intel.com>:
>> @@ -185,7 +193,23 @@ int pa_daemon_conf_set_log_target(pa_daemon_conf
>*c, const char *string) {
>>     } else if (!strcmp(string, "stderr")) {
>>         c->auto_log_target = 0;
>>         c->log_target = PA_LOG_STDERR;
>> -    } else
>> +    } else if (pa_startswith(string, "file:")) {
>> +        char file_path[512];
>> +
>> +        strncpy(file_path, string+5, sizeof(file_path));
>
>This is potentially unsafe, use pa_strlcpy.

Ok I will use it instead.

>
>> +
>> +        /* Open target file with user rights */
>> +        if ((log_fd = open(file_path, O_RDWR|O_TRUNC|O_CREAT,
>S_IRWXU)) >= 0) {
>> +            c->auto_log_target = 0;
>> +            c->log_target = PA_LOG_FD;
>> +            pa_log_set_fd(log_fd);
>> +        }
>> +        else {
>> +            printf("Failed to open target file %s, error : %s\n",
>file_path, pa_cstrerror(errno));
>> +            return -1;
>> +        }
>> +    }
>> +    else
>>         return -1;
>>
>>     return 0;
>
>
>> @@ -399,6 +407,24 @@ void pa_log_levelv_meta(
>>             }
>>  #endif
>>
>> +            case PA_LOG_FD: {
>> +                if (log_fd != -1) {
>> +                    char metadata[256];
>> +
>> +                    pa_snprintf(metadata, sizeof(metadata), "\n%c
>%s%s", level_to_char[level], timestamp, location);
>> +
>> +                    if ((write(log_fd, metadata, strlen(metadata)) <
>0) || (write(log_fd, t, strlen(t)) < 0)) {
>> +                        saved_errno = errno;
>> +                        pa_close(log_fd);
>> +                        log_fd = -1;
>> +                    }
>> +                }
>> +                else
>> +                    fprintf(stderr, "%s\n", "Invalid file descriptor.
>Could not write log message.");
>
>Wouldn't this result in lots and lots of the same messages to stderr?
>It seems better to move this message to the case when the write fails,
>or just print the log message here, or both.

Yes it will indeed. So we probably prefer to print first the log message itself then print a warning message with the errno - using printf, then change the target dynamically to PA_LOG_STDERR as Arun suggested, using pa_log_set_target(). Also the target in daemon configuration will stay PA_LOG_FD which should be no problem. Also calling twice pa_close is harmless I guess, but we could probably remove it from here. 

>
>> +
>> +                break;
>> +            }
>> +
>>             case PA_LOG_NULL:
>>             default:
>>                 break;
>
>Maarten
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