SystemTap: print.c Source File

00001 #ifndef _PRINT_C_ /* -*- linux-c -*- */
-00002 #define _PRINT_C_
-00003 
-00004 #include <linux/config.h>
-00005 
-00006 #include "io.c"
-00007 
-00008 /** @file print.c
-00009  * @addtogroup print Print Buffer
-00010  * Print Buffer Functions.
-00011  * The print buffer is for collecting output to send to the user daemon.
-00012  * This is a per-cpu static buffer.  The buffer is sent when
-00013  * _stp_print_flush() is called.
-00014  *
-00015  * The reason to do this is to allow multiple small prints to be combined then
-00016  * timestamped and sent together to stpd. It could flush automatically on newlines,
-00017  * but what about stack traces which span many lines?  So try this and see how it works for us.
-00018  * @{
-00019  */
-00020 
-00021 /** Size of buffer, not including terminating NULL */
-00022 #define STP_PRINT_BUF_LEN 8000
-00023 
-00024 static int _stp_pbuf_len[NR_CPUS];
-00025 
-00026 #ifdef STP_NETLINK_ONLY
-00027 #define STP_PRINT_BUF_START 0
-00028 static char _stp_pbuf[NR_CPUS][STP_PRINT_BUF_LEN + 1];
-00029 
-00030 void _stp_print_flush (void)
-00031 {
-00032         int cpu = smp_processor_id();
-00033         char *buf = &_stp_pbuf[cpu][0];
-00034         int len = _stp_pbuf_len[cpu];
-00035 
-00036         if (len == 0)
-00037                 return;
-00038 
-00039         if ( app.logging == 0) {
-00040                 _stp_pbuf_len[cpu] = 0;
-00041                 return;
-00042         }
-00043         
-00044         /* enforce newline at end  */
-00045         if (buf[len - 1] != '\n') {
-00046                 buf[len++] = '\n';
-00047                 buf[len] = '\0';
-00048         }
-00049         
-00050         send_reply (STP_REALTIME_DATA, buf, len + 1, stpd_pid);
-00051         _stp_pbuf_len[cpu] = 0;
-00052 }
-00053 
-00054 #else /* ! STP_NETLINK_ONLY */
-00055 /* size of timestamp, in bytes, including space */
-00056 #define TIMESTAMP_SIZE 19
-00057 #define STP_PRINT_BUF_START (TIMESTAMP_SIZE + 1)
-00058 static char _stp_pbuf[NR_CPUS][STP_PRINT_BUF_LEN + STP_PRINT_BUF_START + 1];
-00059 
-00060 /** Send the print buffer now.
-00061  * Output accumulates in the print buffer until this is called.
-00062  * Size is limited by length of print buffer, #STP_PRINT_BUF_LEN.
-00063  */
-00064 
-00065 void _stp_print_flush (void)
-00066 {
-00067         int cpu = smp_processor_id();
-00068         char *buf = &_stp_pbuf[cpu][0];
-00069         char *ptr = buf + STP_PRINT_BUF_START;
-00070         struct timeval tv;
-00071 
-00072         if (_stp_pbuf_len[cpu] == 0)
-00073                 return;
-00074         
-00075         /* enforce newline at end  */
-00076         if (ptr[_stp_pbuf_len[cpu]-1] != '\n') {
-00077                 ptr[_stp_pbuf_len[cpu]++] = '\n';
-00078                 ptr[_stp_pbuf_len[cpu]] = '\0';
-00079         }
-00080         
-00081         do_gettimeofday(&tv);
-00082         scnprintf (buf, TIMESTAMP_SIZE+1, "[%li.%06li] ", tv.tv_sec, tv.tv_usec);
-00083         buf[TIMESTAMP_SIZE] = ' ';
-00084         relayapp_write(buf, _stp_pbuf_len[cpu] + TIMESTAMP_SIZE + 2);
-00085         _stp_pbuf_len[cpu] = 0;
-00086 }
-00087 #endif /* STP_NETLINK_ONLY */
-00088 
-00089 /** Print into the print buffer.
-00090  * Like printf, except output goes to the print buffer.
-00091  * Safe because overflowing the buffer is not allowed.
-00092  * Size is limited by length of print buffer, #STP_PRINT_BUF_LEN.
-00093  * 
-00094  * @param fmt A printf-style format string followed by a 
-00095  * variable number of args.
-00096  * @sa _stp_print_flush()
-00097  */
-00098 
-00099 void _stp_printf (const char *fmt, ...)
-00100 {
-00101         int num;
-00102         va_list args;
-00103         int cpu = smp_processor_id();
-00104         char *buf = &_stp_pbuf[cpu][STP_PRINT_BUF_START] + _stp_pbuf_len[cpu];
-00105         va_start(args, fmt);
-00106         num = vscnprintf(buf, STP_PRINT_BUF_LEN - _stp_pbuf_len[cpu], fmt, args);
-00107         va_end(args);
-00108         if (num > 0)
-00109                 _stp_pbuf_len[cpu] += num;
-00110 }
-00111 
-00112 /** Print into the print buffer.
-00113  * Use this if your function already has a va_list.
-00114  * You probably want _stp_printf().
-00115  */
-00116 
-00117 void _stp_vprintf (const char *fmt, va_list args)
-00118 {
-00119         int num;
-00120         int cpu = smp_processor_id();
-00121         char *buf = &_stp_pbuf[cpu][STP_PRINT_BUF_START] + _stp_pbuf_len[cpu];
-00122         num = vscnprintf(buf, STP_PRINT_BUF_LEN -_stp_pbuf_len[cpu], fmt, args);
-00123         if (num > 0)
-00124                 _stp_pbuf_len[cpu] += num;
-00125 }
-00126 
-00127 /** Write a C string into the print buffer.
-00128  * Copies a string into a print buffer.
-00129  * Safe because overflowing the buffer is not allowed.
-00130  * Size is limited by length of print buffer, #STP_PRINT_BUF_LEN.
-00131  * This is more efficient than using _stp_printf() if you don't
-00132  * need fancy formatting.
-00133  *
-00134  * @param str A C string.
-00135  * @sa _stp_print
-00136  */
-00137 
-00138 void _stp_print_cstr (const char *str)
-00139 {
-00140         int cpu = smp_processor_id();
-00141         char *buf = &_stp_pbuf[cpu][STP_PRINT_BUF_START] + _stp_pbuf_len[cpu];
-00142         int num = strlen (str);
-00143         if (num > STP_PRINT_BUF_LEN - _stp_pbuf_len[cpu])
-00144                 num = STP_PRINT_BUF_LEN - _stp_pbuf_len[cpu];
-00145         strncpy (buf, str, num+1);
-00146         _stp_pbuf_len[cpu] += num;
-00147 }
-00148 
-00149 /** Clear the scratch buffer.
-00150  * This function should be called before anything is written to 
-00151  * the scratch buffer.  Output will accumulate in the buffer
-00152  * until this function is called again.  
-00153  * @returns A pointer to the buffer.
-00154  */
-00155 
-00156 char *_stp_print_clear (void)
-00157 {
-00158         int cpu = smp_processor_id();
-00159         _stp_pbuf_len[cpu] = 0;
-00160         return &_stp_pbuf[cpu][STP_PRINT_BUF_START];
-00161 }
-00162 
-00163 #include "string.c"
-00164 
-00165 /** Write a String into the print buffer.
-00166  * Copies a String into a print buffer.
-00167  * Safe because overflowing the buffer is not allowed.
-00168  * Size is limited by length of print buffer, #STP_PRINT_BUF_LEN.
-00169  * This is more efficient than using _stp_printf() if you don't
-00170  * need fancy formatting.
-00171  *
-00172  * @param str A String.
-00173  * @sa _stp_print
-00174  */
-00175 
-00176 void _stp_print_string (String str)
-00177 {
-00178         if (str->len)
-00179                 _stp_print_cstr (str->buf);
-00180 }
-00181 
-00182 /** Write a String or C string into the print buffer.
-00183  * This macro selects the proper function to call.
-00184  * @param str A String or C string (char *)
-00185  * @sa _stp_print_cstr _stp_print_string
-00186  */
-00187 
-00188 #define _stp_print(str)                                                 \
-00189         ({                                                              \
-00190           if (__builtin_types_compatible_p (typeof (str), char[])) {    \
-00191                   char *x = (char *)str;                                \
-00192                   _stp_print_cstr(x);                                   \
-00193           } else {                                                      \
-00194                   String x = (String)str;                               \
-00195                   _stp_print_string(x);                                 \
-00196           }                                                             \
-00197   })
-00198 
-00199 /** @} */
-00200 #endif /* _PRINT_C_ */
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