2 * procfile is a library for reading kernel files from /proc
6 * - every file is opened once with procfile_open().
8 * - to read updated contents, we rewind it (lseek() to 0) and read again
9 * with procfile_readall().
11 * - for every file, we use a buffer that is adjusted to fit its entire
12 * contents in memory, allowing us to read it with a single read() call.
13 * (this provides atomicity / consistency on the data read from the kernel)
15 * - once the data are read, we update two arrays of pointers:
16 * - a words array, pointing to each word in the data read
17 * - a lines array, pointing to the first word for each line
19 * This is highly optimized. Both arrays are automatically adjusted to
20 * fit all contents and are updated in a single pass on the data:
21 * - a raspberry Pi can process 5.000+ files / sec.
22 * - a J1900 celeron processor can process 23.000+ files / sec.
26 #ifndef NETDATA_PROCFILE_H
27 #define NETDATA_PROCFILE_H 1
29 // ----------------------------------------------------------------------------
33 size_t len; // used entries
34 size_t size; // capacity
35 char *words[]; // array of pointers
39 // ----------------------------------------------------------------------------
43 size_t words; // how many words this line has
44 size_t first; // the id of the first word of this line
49 size_t len; // used entries
50 size_t size; // capacity
51 ffline lines[]; // array of lines
55 // ----------------------------------------------------------------------------
58 #define PROCFILE_FLAG_DEFAULT 0x00000000
59 #define PROCFILE_FLAG_NO_ERROR_ON_FILE_IO 0x00000001
62 char filename[FILENAME_MAX + 1]; // not populated until profile_filename() is called
65 int fd; // the file desriptor
66 size_t len; // the bytes we have placed into data
67 size_t size; // the bytes we have allocated for data
71 char data[]; // allocated buffer to keep file contents
74 // close the proc file and free all related memory
75 extern void procfile_close(procfile *ff);
77 // (re)read and parse the proc file
78 extern procfile *procfile_readall(procfile *ff);
80 // open a /proc or /sys file
81 extern procfile *procfile_open(const char *filename, const char *separators, uint32_t flags);
84 // if separators == NULL, the last separators are used
85 extern procfile *procfile_reopen(procfile *ff, const char *filename, const char *separators, uint32_t flags);
87 // example walk-through a procfile parsed file
88 extern void procfile_print(procfile *ff);
90 extern void procfile_set_quotes(procfile *ff, const char *quotes);
91 extern void procfile_set_open_close(procfile *ff, const char *open, const char *close);
93 extern char *procfile_filename(procfile *ff);
95 // ----------------------------------------------------------------------------
97 // set this to 1, to have procfile adapt its initial buffer allocation to the max allocation used so far
98 extern int procfile_adaptive_initial_allocation;
100 // return the number of lines present
101 #define procfile_lines(ff) (ff->lines->len)
103 // return the number of words of the Nth line
104 #define procfile_linewords(ff, line) (((line) < procfile_lines(ff)) ? (ff)->lines->lines[(line)].words : 0)
106 // return the Nth word of the file, or empty string
107 #define procfile_word(ff, word) (((word) < (ff)->words->len) ? (ff)->words->words[(word)] : "")
109 // return the first word of the Nth line, or empty string
110 #define procfile_line(ff, line) (((line) < procfile_lines(ff)) ? procfile_word((ff), (ff)->lines->lines[(line)].first) : "")
112 // return the Nth word of the current line
113 #define procfile_lineword(ff, line, word) (((line) < procfile_lines(ff) && (word) < procfile_linewords(ff, (line))) ? procfile_word((ff), (ff)->lines->lines[(line)].first + word) : "")
115 #endif /* NETDATA_PROCFILE_H */