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Diffstat (limited to '')
| -rw-r--r-- | libnetdata/procfile/Makefile.am | 8 | ||||
| -rw-r--r-- | libnetdata/procfile/README.md | 67 | ||||
| -rw-r--r-- | libnetdata/procfile/procfile.c | 472 | ||||
| -rw-r--r-- | libnetdata/procfile/procfile.h | 106 |
4 files changed, 653 insertions, 0 deletions
diff --git a/libnetdata/procfile/Makefile.am b/libnetdata/procfile/Makefile.am new file mode 100644 index 0000000..161784b --- /dev/null +++ b/libnetdata/procfile/Makefile.am @@ -0,0 +1,8 @@ +# SPDX-License-Identifier: GPL-3.0-or-later + +AUTOMAKE_OPTIONS = subdir-objects +MAINTAINERCLEANFILES = $(srcdir)/Makefile.in + +dist_noinst_DATA = \ + README.md \ + $(NULL) diff --git a/libnetdata/procfile/README.md b/libnetdata/procfile/README.md new file mode 100644 index 0000000..3eeb1e2 --- /dev/null +++ b/libnetdata/procfile/README.md @@ -0,0 +1,67 @@ +<!-- +title: "PROCFILE" +custom_edit_url: https://github.com/netdata/netdata/edit/master/libnetdata/procfile/README.md +--> + +# PROCFILE + +procfile is a library for reading text data files (i.e `/proc` files) in the fastest possible way. + +## How it works + +The library automatically adapts (through the iterations) its memory so that each file +is read with single `read()` call. + +Then the library splits the file into words, using the supplied separators. +The library also supported quoted words (i.e. strings within of which the separators are ignored). + +### Initialization + +Initially the caller: + +- calls `procfile_open()` to open the file and allocate the structures needed. + +### Iterations + +For each iteration, the caller: + +- calls `procfile_readall()` to read updated contents. + This call also rewinds (`lseek()` to 0) before reading it. + + For every file, a [BUFFER](/libnetdata/buffer/README.md) is used that is automatically adjusted to fit the entire + file contents of the file. So the file is read with a single `read()` call (providing atomicity / consistency when + the data are read from the kernel). + + Once the data are read, 2 arrays of pointers are updated: + + - a `words` array, pointing to each word in the data read + - a `lines` array, pointing to the first word for each line + + This is highly optimized. Both arrays are automatically adjusted to + fit all contents and are updated in a single pass on the data. + + The library provides a number of macros: + + - `procfile_lines()` returns the # of lines read + - `procfile_linewords()` returns the # of words in the given line + - `procfile_word()` returns a pointer the given word # + - `procfile_line()` returns a pointer to the first word of the given line # + - `procfile_lineword()` returns a pointer to the given word # of the given line # + +### Cleanup + +When the caller exits: + +- calls `procfile_free()` to close the file and free all memory used. + +### Performance + +- a **raspberry Pi 1** (the oldest single core one) can process 5.000+ `/proc` files per second. +- a **J1900 Celeron** processor can process 23.000+ `/proc` files per second per core. + +To achieve this kind of performance, the library tries to work in batches so that the code +and the data are inside the processor's caches. + +This library is extensively used in Netdata and its plugins. + +[](<>) diff --git a/libnetdata/procfile/procfile.c b/libnetdata/procfile/procfile.c new file mode 100644 index 0000000..4a812ba --- /dev/null +++ b/libnetdata/procfile/procfile.c @@ -0,0 +1,472 @@ +// SPDX-License-Identifier: GPL-3.0-or-later + +#include "../libnetdata.h" + +#define PF_PREFIX "PROCFILE" + +#define PFWORDS_INCREASE_STEP 200 +#define PFLINES_INCREASE_STEP 10 +#define PROCFILE_INCREMENT_BUFFER 512 + +int procfile_open_flags = O_RDONLY; + +int procfile_adaptive_initial_allocation = 0; + +// if adaptive allocation is set, these store the +// max values we have seen so far +size_t procfile_max_lines = PFLINES_INCREASE_STEP; +size_t procfile_max_words = PFWORDS_INCREASE_STEP; +size_t procfile_max_allocation = PROCFILE_INCREMENT_BUFFER; + + +// ---------------------------------------------------------------------------- + +char *procfile_filename(procfile *ff) { + if(ff->filename[0]) return ff->filename; + + char buffer[FILENAME_MAX + 1]; + snprintfz(buffer, FILENAME_MAX, "/proc/self/fd/%d", ff->fd); + + ssize_t l = readlink(buffer, ff->filename, FILENAME_MAX); + if(unlikely(l == -1)) + snprintfz(ff->filename, FILENAME_MAX, "unknown filename for fd %d", ff->fd); + else + ff->filename[l] = '\0'; + + // on non-linux systems, something like this will be needed + // fcntl(ff->fd, F_GETPATH, ff->filename) + + return ff->filename; +} + +// ---------------------------------------------------------------------------- +// An array of words + +static inline void pfwords_add(procfile *ff, char *str) { + // debug(D_PROCFILE, PF_PREFIX ": adding word No %d: '%s'", fw->len, str); + + pfwords *fw = ff->words; + if(unlikely(fw->len == fw->size)) { + // debug(D_PROCFILE, PF_PREFIX ": expanding words"); + + ff->words = fw = reallocz(fw, sizeof(pfwords) + (fw->size + PFWORDS_INCREASE_STEP) * sizeof(char *)); + fw->size += PFWORDS_INCREASE_STEP; + } + + fw->words[fw->len++] = str; +} + +NEVERNULL +static inline pfwords *pfwords_new(void) { + // debug(D_PROCFILE, PF_PREFIX ": initializing words"); + + size_t size = (procfile_adaptive_initial_allocation) ? procfile_max_words : PFWORDS_INCREASE_STEP; + + pfwords *new = mallocz(sizeof(pfwords) + size * sizeof(char *)); + new->len = 0; + new->size = size; + return new; +} + +static inline void pfwords_reset(pfwords *fw) { + // debug(D_PROCFILE, PF_PREFIX ": reseting words"); + fw->len = 0; +} + +static inline void pfwords_free(pfwords *fw) { + // debug(D_PROCFILE, PF_PREFIX ": freeing words"); + + freez(fw); +} + + +// ---------------------------------------------------------------------------- +// An array of lines + +NEVERNULL +static inline size_t *pflines_add(procfile *ff) { + // debug(D_PROCFILE, PF_PREFIX ": adding line %d at word %d", fl->len, first_word); + + pflines *fl = ff->lines; + if(unlikely(fl->len == fl->size)) { + // debug(D_PROCFILE, PF_PREFIX ": expanding lines"); + + ff->lines = fl = reallocz(fl, sizeof(pflines) + (fl->size + PFLINES_INCREASE_STEP) * sizeof(ffline)); + fl->size += PFLINES_INCREASE_STEP; + } + + ffline *ffl = &fl->lines[fl->len++]; + ffl->words = 0; + ffl->first = ff->words->len; + + return &ffl->words; +} + +NEVERNULL +static inline pflines *pflines_new(void) { + // debug(D_PROCFILE, PF_PREFIX ": initializing lines"); + + size_t size = (unlikely(procfile_adaptive_initial_allocation)) ? procfile_max_words : PFLINES_INCREASE_STEP; + + pflines *new = mallocz(sizeof(pflines) + size * sizeof(ffline)); + new->len = 0; + new->size = size; + return new; +} + +static inline void pflines_reset(pflines *fl) { + // debug(D_PROCFILE, PF_PREFIX ": reseting lines"); + + fl->len = 0; +} + +static inline void pflines_free(pflines *fl) { + // debug(D_PROCFILE, PF_PREFIX ": freeing lines"); + + freez(fl); +} + + +// ---------------------------------------------------------------------------- +// The procfile + +void procfile_close(procfile *ff) { + if(unlikely(!ff)) return; + + debug(D_PROCFILE, PF_PREFIX ": Closing file '%s'", procfile_filename(ff)); + + if(likely(ff->lines)) pflines_free(ff->lines); + if(likely(ff->words)) pfwords_free(ff->words); + + if(likely(ff->fd != -1)) close(ff->fd); + freez(ff); +} + +NOINLINE +static void procfile_parser(procfile *ff) { + // debug(D_PROCFILE, PF_PREFIX ": Parsing file '%s'", ff->filename); + + char *s = ff->data // our current position + , *e = &ff->data[ff->len] // the terminating null + , *t = ff->data; // the first character of a word (or quoted / parenthesized string) + + // the look up array to find our type of character + PF_CHAR_TYPE *separators = ff->separators; + + char quote = 0; // the quote character - only when in quoted string + size_t opened = 0; // counts the number of open parenthesis + + size_t *line_words = pflines_add(ff); + + while(s < e) { + PF_CHAR_TYPE ct = separators[(unsigned char)(*s)]; + + // this is faster than a switch() + // read more here: http://lazarenko.me/switch/ + if(likely(ct == PF_CHAR_IS_WORD)) { + s++; + } + else if(likely(ct == PF_CHAR_IS_SEPARATOR)) { + if(!quote && !opened) { + if (s != t) { + // separator, but we have word before it + *s = '\0'; + pfwords_add(ff, t); + (*line_words)++; + t = ++s; + } + else { + // separator at the beginning + // skip it + t = ++s; + } + } + else { + // we are inside a quote or parenthesized string + s++; + } + } + else if(likely(ct == PF_CHAR_IS_NEWLINE)) { + // end of line + + *s = '\0'; + pfwords_add(ff, t); + (*line_words)++; + t = ++s; + + // debug(D_PROCFILE, PF_PREFIX ": ended line %d with %d words", l, ff->lines->lines[l].words); + + line_words = pflines_add(ff); + } + else if(likely(ct == PF_CHAR_IS_QUOTE)) { + if(unlikely(!quote && s == t)) { + // quote opened at the beginning + quote = *s; + t = ++s; + } + else if(unlikely(quote && quote == *s)) { + // quote closed + quote = 0; + + *s = '\0'; + pfwords_add(ff, t); + (*line_words)++; + t = ++s; + } + else + s++; + } + else if(likely(ct == PF_CHAR_IS_OPEN)) { + if(s == t) { + opened++; + t = ++s; + } + else if(opened) { + opened++; + s++; + } + else + s++; + } + else if(likely(ct == PF_CHAR_IS_CLOSE)) { + if(opened) { + opened--; + + if(!opened) { + *s = '\0'; + pfwords_add(ff, t); + (*line_words)++; + t = ++s; + } + else + s++; + } + else + s++; + } + else + fatal("Internal Error: procfile_readall() does not handle all the cases."); + } + + if(likely(s > t && t < e)) { + // the last word + if(unlikely(ff->len >= ff->size)) { + // we are going to loose the last byte + s = &ff->data[ff->size - 1]; + } + + *s = '\0'; + pfwords_add(ff, t); + (*line_words)++; + // t = ++s; + } +} + +procfile *procfile_readall(procfile *ff) { + // debug(D_PROCFILE, PF_PREFIX ": Reading file '%s'.", ff->filename); + + ff->len = 0; // zero the used size + ssize_t r = 1; // read at least once + while(r > 0) { + ssize_t s = ff->len; + ssize_t x = ff->size - s; + + if(unlikely(!x)) { + debug(D_PROCFILE, PF_PREFIX ": Expanding data buffer for file '%s'.", procfile_filename(ff)); + ff = reallocz(ff, sizeof(procfile) + ff->size + PROCFILE_INCREMENT_BUFFER); + ff->size += PROCFILE_INCREMENT_BUFFER; + } + + debug(D_PROCFILE, "Reading file '%s', from position %zd with length %zd", procfile_filename(ff), s, (ssize_t)(ff->size - s)); + r = read(ff->fd, &ff->data[s], ff->size - s); + if(unlikely(r == -1)) { + if(unlikely(!(ff->flags & PROCFILE_FLAG_NO_ERROR_ON_FILE_IO))) error(PF_PREFIX ": Cannot read from file '%s' on fd %d", procfile_filename(ff), ff->fd); + procfile_close(ff); + return NULL; + } + + ff->len += r; + } + + // debug(D_PROCFILE, "Rewinding file '%s'", ff->filename); + if(unlikely(lseek(ff->fd, 0, SEEK_SET) == -1)) { + if(unlikely(!(ff->flags & PROCFILE_FLAG_NO_ERROR_ON_FILE_IO))) error(PF_PREFIX ": Cannot rewind on file '%s'.", procfile_filename(ff)); + procfile_close(ff); + return NULL; + } + + pflines_reset(ff->lines); + pfwords_reset(ff->words); + procfile_parser(ff); + + if(unlikely(procfile_adaptive_initial_allocation)) { + if(unlikely(ff->len > procfile_max_allocation)) procfile_max_allocation = ff->len; + if(unlikely(ff->lines->len > procfile_max_lines)) procfile_max_lines = ff->lines->len; + if(unlikely(ff->words->len > procfile_max_words)) procfile_max_words = ff->words->len; + } + + // debug(D_PROCFILE, "File '%s' updated.", ff->filename); + return ff; +} + +NOINLINE +static void procfile_set_separators(procfile *ff, const char *separators) { + static PF_CHAR_TYPE def[256]; + static char initilized = 0; + + if(unlikely(!initilized)) { + // this is thread safe + // if initialized is zero, multiple threads may be executing + // this code at the same time, setting in def[] the exact same values + int i = 256; + while(i--) { + if(unlikely(i == '\n' || i == '\r')) + def[i] = PF_CHAR_IS_NEWLINE; + + else if(unlikely(isspace(i) || !isprint(i))) + def[i] = PF_CHAR_IS_SEPARATOR; + + else + def[i] = PF_CHAR_IS_WORD; + } + + initilized = 1; + } + + // copy the default + PF_CHAR_TYPE *ffs = ff->separators, *ffd = def, *ffe = &def[256]; + while(ffd != ffe) + *ffs++ = *ffd++; + + // set the separators + if(unlikely(!separators)) + separators = " \t=|"; + + ffs = ff->separators; + const char *s = separators; + while(*s) + ffs[(int)*s++] = PF_CHAR_IS_SEPARATOR; +} + +void procfile_set_quotes(procfile *ff, const char *quotes) { + PF_CHAR_TYPE *ffs = ff->separators; + + // remove all quotes + int i = 256; + while(i--) + if(unlikely(ffs[i] == PF_CHAR_IS_QUOTE)) + ffs[i] = PF_CHAR_IS_WORD; + + // if nothing given, return + if(unlikely(!quotes || !*quotes)) + return; + + // set the quotes + const char *s = quotes; + while(*s) + ffs[(int)*s++] = PF_CHAR_IS_QUOTE; +} + +void procfile_set_open_close(procfile *ff, const char *open, const char *close) { + PF_CHAR_TYPE *ffs = ff->separators; + + // remove all open/close + int i = 256; + while(i--) + if(unlikely(ffs[i] == PF_CHAR_IS_OPEN || ffs[i] == PF_CHAR_IS_CLOSE)) + ffs[i] = PF_CHAR_IS_WORD; + + // if nothing given, return + if(unlikely(!open || !*open || !close || !*close)) + return; + + // set the openings + const char *s = open; + while(*s) + ffs[(int)*s++] = PF_CHAR_IS_OPEN; + + // set the closings + s = close; + while(*s) + ffs[(int)*s++] = PF_CHAR_IS_CLOSE; +} + +procfile *procfile_open(const char *filename, const char *separators, uint32_t flags) { + debug(D_PROCFILE, PF_PREFIX ": Opening file '%s'", filename); + + int fd = open(filename, procfile_open_flags, 0666); + if(unlikely(fd == -1)) { + if(unlikely(!(flags & PROCFILE_FLAG_NO_ERROR_ON_FILE_IO))) error(PF_PREFIX ": Cannot open file '%s'", filename); + return NULL; + } + + // info("PROCFILE: opened '%s' on fd %d", filename, fd); + + size_t size = (unlikely(procfile_adaptive_initial_allocation)) ? procfile_max_allocation : PROCFILE_INCREMENT_BUFFER; + procfile *ff = mallocz(sizeof(procfile) + size); + + //strncpyz(ff->filename, filename, FILENAME_MAX); + ff->filename[0] = '\0'; + + ff->fd = fd; + ff->size = size; + ff->len = 0; + ff->flags = flags; + + ff->lines = pflines_new(); + ff->words = pfwords_new(); + + procfile_set_separators(ff, separators); + + debug(D_PROCFILE, "File '%s' opened.", filename); + return ff; +} + +procfile *procfile_reopen(procfile *ff, const char *filename, const char *separators, uint32_t flags) { + if(unlikely(!ff)) return procfile_open(filename, separators, flags); + + if(likely(ff->fd != -1)) { + // info("PROCFILE: closing fd %d", ff->fd); + close(ff->fd); + } + + ff->fd = open(filename, procfile_open_flags, 0666); + if(unlikely(ff->fd == -1)) { + procfile_close(ff); + return NULL; + } + + // info("PROCFILE: opened '%s' on fd %d", filename, ff->fd); + + //strncpyz(ff->filename, filename, FILENAME_MAX); + ff->filename[0] = '\0'; + ff->flags = flags; + + // do not do the separators again if NULL is given + if(likely(separators)) procfile_set_separators(ff, separators); + + return ff; +} + +// ---------------------------------------------------------------------------- +// example parsing of procfile data + +void procfile_print(procfile *ff) { + size_t lines = procfile_lines(ff), l; + char *s; + (void)s; + + debug(D_PROCFILE, "File '%s' with %zu lines and %zu words", procfile_filename(ff), ff->lines->len, ff->words->len); + + for(l = 0; likely(l < lines) ;l++) { + size_t words = procfile_linewords(ff, l); + + debug(D_PROCFILE, " line %zu starts at word %zu and has %zu words", l, ff->lines->lines[l].first, ff->lines->lines[l].words); + + size_t w; + for(w = 0; likely(w < words) ;w++) { + s = procfile_lineword(ff, l, w); + debug(D_PROCFILE, " [%zu.%zu] '%s'", l, w, s); + } + } +} diff --git a/libnetdata/procfile/procfile.h b/libnetdata/procfile/procfile.h new file mode 100644 index 0000000..b107358 --- /dev/null +++ b/libnetdata/procfile/procfile.h @@ -0,0 +1,106 @@ +// SPDX-License-Identifier: GPL-3.0-or-later + +#ifndef NETDATA_PROCFILE_H +#define NETDATA_PROCFILE_H 1 + +#include "../libnetdata.h" + +// ---------------------------------------------------------------------------- +// An array of words + +typedef struct { + size_t len; // used entries + size_t size; // capacity + char *words[]; // array of pointers +} pfwords; + + +// ---------------------------------------------------------------------------- +// An array of lines + +typedef struct { + size_t words; // how many words this line has + size_t first; // the id of the first word of this line + // in the words array +} ffline; + +typedef struct { + size_t len; // used entries + size_t size; // capacity + ffline lines[]; // array of lines +} pflines; + + +// ---------------------------------------------------------------------------- +// The procfile + +#define PROCFILE_FLAG_DEFAULT 0x00000000 +#define PROCFILE_FLAG_NO_ERROR_ON_FILE_IO 0x00000001 + +typedef enum procfile_separator { + PF_CHAR_IS_SEPARATOR, + PF_CHAR_IS_NEWLINE, + PF_CHAR_IS_WORD, + PF_CHAR_IS_QUOTE, + PF_CHAR_IS_OPEN, + PF_CHAR_IS_CLOSE +} PF_CHAR_TYPE; + +typedef struct { + char filename[FILENAME_MAX + 1]; // not populated until profile_filename() is called + + uint32_t flags; + int fd; // the file desriptor + size_t len; // the bytes we have placed into data + size_t size; // the bytes we have allocated for data + pflines *lines; + pfwords *words; + PF_CHAR_TYPE separators[256]; + char data[]; // allocated buffer to keep file contents +} procfile; + +// close the proc file and free all related memory +extern void procfile_close(procfile *ff); + +// (re)read and parse the proc file +extern procfile *procfile_readall(procfile *ff); + +// open a /proc or /sys file +extern procfile *procfile_open(const char *filename, const char *separators, uint32_t flags); + +// re-open a file +// if separators == NULL, the last separators are used +extern procfile *procfile_reopen(procfile *ff, const char *filename, const char *separators, uint32_t flags); + +// example walk-through a procfile parsed file +extern void procfile_print(procfile *ff); + +extern void procfile_set_quotes(procfile *ff, const char *quotes); +extern void procfile_set_open_close(procfile *ff, const char *open, const char *close); + +extern char *procfile_filename(procfile *ff); + +// ---------------------------------------------------------------------------- + +// set to the O_XXXX flags, to have procfile_open and procfile_reopen use them when opening proc files +extern int procfile_open_flags; + +// set this to 1, to have procfile adapt its initial buffer allocation to the max allocation used so far +extern int procfile_adaptive_initial_allocation; + +// return the number of lines present +#define procfile_lines(ff) ((ff)->lines->len) + +// return the number of words of the Nth line +#define procfile_linewords(ff, line) (((line) < procfile_lines(ff)) ? (ff)->lines->lines[(line)].words : 0) + +// return the Nth word of the file, or empty string +#define procfile_word(ff, word) (((word) < (ff)->words->len) ? (ff)->words->words[(word)] : "") + +// return the first word of the Nth line, or empty string +#define procfile_line(ff, line) (((line) < procfile_lines(ff)) ? procfile_word((ff), (ff)->lines->lines[(line)].first) : "") + +// return the Nth word of the current line +#define procfile_lineword(ff, line, word) (((line) < procfile_lines(ff) && (word) < procfile_linewords((ff), (line))) ? procfile_word((ff), (ff)->lines->lines[(line)].first + (word)) : "") + +#endif /* NETDATA_PROCFILE_H */ |