about summary refs log tree commit diff
path: root/src/libutil/util.hh
blob: d7d3e5edf817faa19b22ee413551c04fa74e2e3c (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
#ifndef __UTIL_H
#define __UTIL_H

#include "types.hh"

#include <sys/types.h>
#include <dirent.h>
#include <unistd.h>
#include <signal.h>

#include <cstdio>


namespace nix {


#define foreach(it_type, it, collection)                                \
    for (it_type it = collection.begin(); it != collection.end(); ++it)


/* Return an environment variable. */
string getEnv(const string & key, const string & def = "");

/* Return an absolutized path, resolving paths relative to the
   specified directory, or the current directory otherwise.  The path
   is also canonicalised. */
Path absPath(Path path, Path dir = "");

/* Canonicalise a path by removing all `.' or `..' components and
   double or trailing slashes.  Optionally resolves all symlink
   components such that each component of the resulting path is *not*
   a symbolic link. */
Path canonPath(const Path & path, bool resolveSymlinks = false);

/* Return the directory part of the given canonical path, i.e.,
   everything before the final `/'.  If the path is the root or an
   immediate child thereof (e.g., `/foo'), this means an empty string
   is returned. */
Path dirOf(const Path & path);

/* Return the base name of the given canonical path, i.e., everything
   following the final `/'. */
string baseNameOf(const Path & path);

/* Return true iff the given path exists. */
bool pathExists(const Path & path);

/* Read the contents (target) of a symbolic link.  The result is not
   in any way canonicalised. */
Path readLink(const Path & path);

bool isLink(const Path & path);

/* Read the contents of a directory.  The entries `.' and `..' are
   removed. */
Strings readDirectory(const Path & path);

/* Read the contents of a file into a string. */
string readFile(int fd);
string readFile(const Path & path);

/* Write a string to a file. */
void writeFile(const Path & path, const string & s);

/* Read a line from a file descriptor. */
string readLine(int fd);

/* Write a line to a file descriptor. */
void writeLine(int fd, string s);

/* Compute the sum of the sizes of all files in `path'. */
void computePathSize(const Path & path,
    unsigned long long & bytes, unsigned long long & blocks);

/* Delete a path; i.e., in the case of a directory, it is deleted
   recursively.  Don't use this at home, kids.  The second variant
   returns the number of bytes and blocks freed. */
void deletePath(const Path & path);

void deletePath(const Path & path, unsigned long long & bytesFreed,
    unsigned long long & blocksFreed);

/* Make a path read-only recursively. */
void makePathReadOnly(const Path & path);

/* Create a temporary directory. */
Path createTempDir(const Path & tmpRoot = "", const Path & prefix = "nix",
    bool includePid = true, bool useGlobalCounter = true);

/* Create a directory and all its parents, if necessary.  Returns the
   list of created directories, in order of creation. */
Paths createDirs(const Path & path);

/* Create a file and write the given text to it.  The file is written
   in binary mode (i.e., no end-of-line conversions).  The path should
   not already exist. */
void writeStringToFile(const Path & path, const string & s);

template<class T, class A>
T singleton(const A & a)
{
    T t;
    t.insert(a);
    return t;
}


/* Messages. */


typedef enum {
    ltPretty,   /* nice, nested output */
    ltEscapes,  /* nesting indicated using escape codes (for log2xml) */
    ltFlat      /* no nesting */
} LogType;

extern LogType logType;
extern Verbosity verbosity; /* suppress msgs > this */

class Nest
{
private:
    bool nest;
public:
    Nest();
    ~Nest();
    void open(Verbosity level, const format & f);
    void close();
};

void printMsg_(Verbosity level, const format & f);

#define startNest(varName, level, f) \
    Nest varName; \
    if (level <= verbosity) { \
      varName.open(level, (f)); \
    }

#define printMsg(level, f) \
    do { \
        if (level <= verbosity) { \
            printMsg_(level, (f)); \
        } \
    } while (0)

#define debug(f) printMsg(lvlDebug, f)

void warnOnce(bool & haveWarned, const format & f);

extern void (*writeToStderr) (const unsigned char * buf, size_t count);


/* Wrappers arount read()/write() that read/write exactly the
   requested number of bytes. */
void readFull(int fd, unsigned char * buf, size_t count);
void writeFull(int fd, const unsigned char * buf, size_t count);

MakeError(EndOfFile, Error)


/* Read a file descriptor until EOF occurs. */
string drainFD(int fd);



/* Automatic cleanup of resources. */


template <class T>
struct AutoDeleteArray
{
    T * p;
    AutoDeleteArray(T * p) : p(p) { }
    ~AutoDeleteArray() 
    {
        delete [] p;
    }
};


class AutoDelete
{
    Path path;
    bool del;
    bool recursive;    
public:
    AutoDelete(const Path & p, bool recursive = true);
    ~AutoDelete();
    void cancel();
};


class AutoCloseFD
{
    int fd;
public:
    AutoCloseFD();
    AutoCloseFD(int fd);
    AutoCloseFD(const AutoCloseFD & fd);
    ~AutoCloseFD();
    void operator =(int fd);
    operator int() const;
    void close();
    bool isOpen();
    int borrow();
};


class Pipe
{
public:
    AutoCloseFD readSide, writeSide;
    void create();
};


class AutoCloseDir
{
    DIR * dir;
public:
    AutoCloseDir();
    AutoCloseDir(DIR * dir);
    ~AutoCloseDir();
    void operator =(DIR * dir);
    operator DIR *();
};


class Pid
{
    pid_t pid;
    bool separatePG;
    int killSignal;
public:
    Pid();
    ~Pid();
    void operator =(pid_t pid);
    operator pid_t();
    void kill();
    int wait(bool block);
    void setSeparatePG(bool separatePG);
    void setKillSignal(int signal);
};


/* Kill all processes running under the specified uid by sending them
   a SIGKILL. */
void killUser(uid_t uid);


/* Run a program and return its stdout in a string (i.e., like the
   shell backtick operator). */
string runProgram(Path program, bool searchPath = false,
    const Strings & args = Strings());

/* Close all file descriptors except stdin, stdout, stderr, and those
   listed in the given set.  Good practice in child processes. */
void closeMostFDs(const set<int> & exceptions);

/* Wrapper around _exit() on Unix and ExitProcess() on Windows.  (On
   Cygwin, _exit() doesn't seem to do the right thing.) */
void quickExit(int status);

/* Common initialisation for setuid programs: clear the environment,
   sanitize file handles 0, 1 and 2. */
void setuidCleanup();


/* User interruption. */

extern volatile sig_atomic_t _isInterrupted;

void _interrupted();

void inline checkInterrupt()
{
    if (_isInterrupted) _interrupted();
}

MakeError(Interrupted, BaseError)


/* String packing / unpacking. */
string packStrings(const Strings & strings);
Strings unpackStrings(const string & s);


/* String tokenizer. */
Strings tokenizeString(const string & s, const string & separators = " \t\n\r");


/* Convert the exit status of a child as returned by wait() into an
   error string. */
string statusToString(int status);

bool statusOk(int status);


/* Parse a string into an integer. */
template<class N> bool string2Int(const string & s, N & n)
{
    std::istringstream str(s);
    str >> n;
    return str && str.get() == EOF;
}

string int2String(int n);


/* Return true iff `s' ends in `suffix'. */
bool hasSuffix(const string & s, const string & suffix);


/* Exception handling in destructors: print an error message, then
   ignore the exception. */
void ignoreException();


/* STL functions such as sort() pass a binary function object around
   by value, so it gets cloned a lot.  This is bad if the function
   object has state or is simply large.  This adapter wraps the
   function object to simulate passing by reference. */
template<class F>
struct binary_function_ref_adapter
{
    F * p;

    binary_function_ref_adapter(F * _p)
    {
        p = _p;
    }
    
    typename F::result_type operator () (
        const typename F::first_argument_type & x,
        const typename F::second_argument_type & y)
    {
        return (*p)(x, y);
    }
};


}


#endif /* !__UTIL_H */