genode/repos/os/src/server/trace_fs/util.h

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os: initial version of trace_fs The trace_fs server provides access to a Trace_session by using a File_system_session as frontend. Each trace subject is represented by a directory ('thread_name.subject') that contains specific files ('active', 'cleanup', 'enable', 'events', 'buffer_size' and 'policy'), which are used to control the tracing process of the thread as well as storing the content of its trace buffer. The tracing of a thread is only activated if there is a valid policy installed and the intend to trace the subject was made clear by writing '1' to the 'enable' file. The tracing of a thread may be deactived by writing a '0' to the 'enable' file. A policy may be changed by overwriting the currently used one. In this case the old policy is replaced by the new policy and is automatically utilize. Writing a value to the 'buffer_size' file changes the appointed size of the trace buffer. This value is only evaluted by reactivating the tracing process. The content of the trace buffer may be accessed by reading from the 'events' file. Throughout all tracing session new trace events are appended to this file. Nodes of UNTRACED subjects are kept as long as they do not change their tracing state to DEAD. In this case all nodes are removed from the file system. Subjects that were traced before and are now UNTRACED will only be removed by writing '1' to the 'cleanup' file - even if they are DEAD by now. To use the trace_fs a config similar to the following may be used: ! <start name="trace_fs"> ! <resource name="RAM" quantum="128M"/> ! <provides><service name="File_system"/></provides> ! <config> ! <policy label="noux -> trace" interval="1000" subject_limit="512" trace_quota="64M" /> ! </config> ! </start> 'interval' sets the periode in which the Trace_session is polled. The time is given in milliseconds. 'subject_limit' speficies how many trace subject should by acquired at most when the Trace_session is polled. 'trace_quota' is the amount of quota the trace_fs should use for the Trace_session connection. The remaing amount of RAM quota will be used for the actual nodes of the file system and the 'policy' as well as the 'events' files. In addiition there are 'buffer_size' and 'buffer_size_limit' that define the initial and the upper limit of the size of a trace buffer. Tracing of parent processes or rather threads may be enabled by setting 'parent_levels' to a value greater than '0' (though this attribute is available, the trace session component within core still lacks support for it). A ready-to-use runscript can by found in 'ports/run/noux_trace_fs.run'. Fixes #1049.
2014-01-17 16:04:04 +01:00
/*
* \brief Utilities
* \author Norman Feske
* \date 2012-04-11
*/
#ifndef _UTIL_H_
#define _UTIL_H_
/**
* Return base-name portion of null-terminated path string
*/
static inline char const *basename(char const *path)
{
char const *start = path;
for (; *path; path++)
if (*path == '/')
start = path + 1;
return start;
}
/**
* Return true if specified path is a base name (contains no path delimiters)
*/
static inline bool is_basename(char const *path)
{
for (; *path; path++)
if (*path == '/')
return false;
return true;
}
/**
* Return true if character 'c' occurs in null-terminated string 'str'
*/
static inline bool string_contains(char const *str, char c)
{
for (; *str; str++)
if (*str == c)
return true;
return false;
}
/**
* Return true if 'str' is a valid node name
*/
static inline bool valid_name(char const *str)
{
if (string_contains(str, '/')) return false;
/* must have at least one character */
if (str[0] == 0) return false;
return true;
}
/**
* Return true if 'str' is a valid file name
*/
static inline bool valid_filename(char const *str)
{
if (!str) return false;
/* must have at least one character */
if (str[0] == 0) return false;
/* must not contain '/' or '\' or ':' */
if (string_contains(str, '/') ||
string_contains(str, '\\') ||
string_contains(str, ':'))
return false;
return true;
}
#endif /* _UTIL_H_ */