Adding upstream version 1.12.0.upstream/1.12.0upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1454 insertions, 0 deletions

diff --git a/libnetdata/libnetdata.c b/libnetdata/libnetdata.c
new file mode 100644
index 0000000..095c38c
--- /dev/null
+++ b/libnetdata/libnetdata.c
@@ -0,0 +1,1454 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+#include "libnetdata.h"
+
+#ifdef __APPLE__
+#define INHERIT_NONE 0
+#endif /* __APPLE__ */
+#if defined(__FreeBSD__) || defined(__APPLE__)
+#    define O_NOATIME     0
+#    define MADV_DONTFORK INHERIT_NONE
+#endif /* __FreeBSD__ || __APPLE__*/
+
+struct rlimit rlimit_nofile = { .rlim_cur = 1024, .rlim_max = 1024 };
+int enable_ksm = 1;
+
+volatile sig_atomic_t netdata_exit = 0;
+const char *os_type = NETDATA_OS_TYPE;
+const char *program_version = VERSION;
+
+// ----------------------------------------------------------------------------
+// memory allocation functions that handle failures
+
+// although netdata does not use memory allocations too often (netdata tries to
+// maintain its memory footprint stable during runtime, i.e. all buffers are
+// allocated during initialization and are adapted to current use throughout
+// its lifetime), these can be used to override the default system allocation
+// routines.
+
+#ifdef NETDATA_LOG_ALLOCATIONS
+static __thread struct memory_statistics {
+    volatile ssize_t malloc_calls_made;
+    volatile ssize_t calloc_calls_made;
+    volatile ssize_t realloc_calls_made;
+    volatile ssize_t strdup_calls_made;
+    volatile ssize_t free_calls_made;
+    volatile ssize_t memory_calls_made;
+    volatile ssize_t allocated_memory;
+    volatile ssize_t mmapped_memory;
+} memory_statistics = { 0, 0, 0, 0, 0, 0, 0, 0 };
+
+__thread size_t log_thread_memory_allocations = 0;
+
+static inline void print_allocations(const char *file, const char *function, const unsigned long line, const char *type, size_t size) {
+    static __thread struct memory_statistics old = { 0, 0, 0, 0, 0, 0, 0, 0 };
+
+    fprintf(stderr, "%s iteration %zu MEMORY TRACE: %lu@%s : %s : %s : %zu\n",
+            netdata_thread_tag(),
+            log_thread_memory_allocations,
+            line, file, function,
+            type, size
+    );
+
+    fprintf(stderr, "%s iteration %zu MEMORY ALLOCATIONS: (%04lu@%-40.40s:%-40.40s): Allocated %zd KiB (%+zd B), mmapped %zd KiB (%+zd B): %s : malloc %zd (%+zd), calloc %zd (%+zd), realloc %zd (%+zd), strdup %zd (%+zd), free %zd (%+zd)\n",
+            netdata_thread_tag(),
+            log_thread_memory_allocations,
+            line, file, function,
+            (memory_statistics.allocated_memory + 512) / 1024, memory_statistics.allocated_memory - old.allocated_memory,
+            (memory_statistics.mmapped_memory + 512) / 1024, memory_statistics.mmapped_memory - old.mmapped_memory,
+            type,
+            memory_statistics.malloc_calls_made, memory_statistics.malloc_calls_made - old.malloc_calls_made,
+            memory_statistics.calloc_calls_made, memory_statistics.calloc_calls_made - old.calloc_calls_made,
+            memory_statistics.realloc_calls_made, memory_statistics.realloc_calls_made - old.realloc_calls_made,
+            memory_statistics.strdup_calls_made, memory_statistics.strdup_calls_made - old.strdup_calls_made,
+            memory_statistics.free_calls_made, memory_statistics.free_calls_made - old.free_calls_made
+    );
+
+    memcpy(&old, &memory_statistics, sizeof(struct memory_statistics));
+}
+
+static inline void mmap_accounting(size_t size) {
+    if(log_thread_memory_allocations) {
+        memory_statistics.memory_calls_made++;
+        memory_statistics.mmapped_memory += size;
+    }
+}
+
+void *mallocz_int(const char *file, const char *function, const unsigned long line, size_t size) {
+    if(log_thread_memory_allocations) {
+        memory_statistics.memory_calls_made++;
+        memory_statistics.malloc_calls_made++;
+        memory_statistics.allocated_memory += size;
+        print_allocations(file, function, line, "malloc()", size);
+    }
+
+    size_t *n = (size_t *)malloc(sizeof(size_t) + size);
+    if (unlikely(!n)) fatal("mallocz() cannot allocate %zu bytes of memory.", size);
+    *n = size;
+    return (void *)&n[1];
+}
+
+void *callocz_int(const char *file, const char *function, const unsigned long line, size_t nmemb, size_t size) {
+    size = nmemb * size;
+
+    if(log_thread_memory_allocations) {
+        memory_statistics.memory_calls_made++;
+        memory_statistics.calloc_calls_made++;
+        memory_statistics.allocated_memory += size;
+        print_allocations(file, function, line, "calloc()", size);
+    }
+
+    size_t *n = (size_t *)calloc(1, sizeof(size_t) + size);
+    if (unlikely(!n)) fatal("callocz() cannot allocate %zu bytes of memory.", size);
+    *n = size;
+    return (void *)&n[1];
+}
+
+void *reallocz_int(const char *file, const char *function, const unsigned long line, void *ptr, size_t size) {
+    if(!ptr) return mallocz_int(file, function, line, size);
+
+    size_t *n = (size_t *)ptr;
+    n--;
+    size_t old_size = *n;
+
+    n = realloc(n, sizeof(size_t) + size);
+    if (unlikely(!n)) fatal("reallocz() cannot allocate %zu bytes of memory (from %zu bytes).", size, old_size);
+
+    if(log_thread_memory_allocations) {
+        memory_statistics.memory_calls_made++;
+        memory_statistics.realloc_calls_made++;
+        memory_statistics.allocated_memory += (size - old_size);
+        print_allocations(file, function, line, "realloc()", size - old_size);
+    }
+
+    *n = size;
+    return (void *)&n[1];
+}
+
+char *strdupz_int(const char *file, const char *function, const unsigned long line, const char *s) {
+    size_t size = strlen(s) + 1;
+
+    if(log_thread_memory_allocations) {
+        memory_statistics.memory_calls_made++;
+        memory_statistics.strdup_calls_made++;
+        memory_statistics.allocated_memory += size;
+        print_allocations(file, function, line, "strdup()", size);
+    }
+
+    size_t *n = (size_t *)malloc(sizeof(size_t) + size);
+    if (unlikely(!n)) fatal("strdupz() cannot allocate %zu bytes of memory.", size);
+
+    *n = size;
+    char *t = (char *)&n[1];
+    strcpy(t, s);
+    return t;
+}
+
+void freez_int(const char *file, const char *function, const unsigned long line, void *ptr) {
+    if(unlikely(!ptr)) return;
+
+    size_t *n = (size_t *)ptr;
+    n--;
+    size_t size = *n;
+
+    if(log_thread_memory_allocations) {
+        memory_statistics.memory_calls_made++;
+        memory_statistics.free_calls_made++;
+        memory_statistics.allocated_memory -= size;
+        print_allocations(file, function, line, "free()", size);
+    }
+
+    free(n);
+}
+#else
+
+char *strdupz(const char *s) {
+    char *t = strdup(s);
+    if (unlikely(!t)) fatal("Cannot strdup() string '%s'", s);
+    return t;
+}
+
+void freez(void *ptr) {
+    free(ptr);
+}
+
+void *mallocz(size_t size) {
+    void *p = malloc(size);
+    if (unlikely(!p)) fatal("Cannot allocate %zu bytes of memory.", size);
+    return p;
+}
+
+void *callocz(size_t nmemb, size_t size) {
+    void *p = calloc(nmemb, size);
+    if (unlikely(!p)) fatal("Cannot allocate %zu bytes of memory.", nmemb * size);
+    return p;
+}
+
+void *reallocz(void *ptr, size_t size) {
+    void *p = realloc(ptr, size);
+    if (unlikely(!p)) fatal("Cannot re-allocate memory to %zu bytes.", size);
+    return p;
+}
+
+#endif
+
+// --------------------------------------------------------------------------------------------------------------------
+
+void json_escape_string(char *dst, const char *src, size_t size) {
+    const char *t;
+    char *d = dst, *e = &dst[size - 1];
+
+    for(t = src; *t && d < e ;t++) {
+        if(unlikely(*t == '\\' || *t == '"')) {
+            if(unlikely(d + 1 >= e)) break;
+            *d++ = '\\';
+        }
+        *d++ = *t;
+    }
+
+    *d = '\0';
+}
+
+void json_fix_string(char *s) {
+    unsigned char c;
+    while((c = (unsigned char)*s)) {
+        if(unlikely(c == '\\'))
+            *s++ = '/';
+        else if(unlikely(c == '"'))
+            *s++ = '\'';
+        else if(unlikely(isspace(c) || iscntrl(c)))
+            *s++ = ' ';
+        else if(unlikely(!isprint(c) || c > 127))
+            *s++ = '_';
+        else
+            s++;
+    }
+}
+
+unsigned char netdata_map_chart_names[256] = {
+        [0] = '\0', //
+        [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] = '0', // 0
+        [49] = '1', // 1
+        [50] = '2', // 2
+        [51] = '3', // 3
+        [52] = '4', // 4
+        [53] = '5', // 5
+        [54] = '6', // 6
+        [55] = '7', // 7
+        [56] = '8', // 8
+        [57] = '9', // 9
+        [58] = '_', // :
+        [59] = '_', // ;
+        [60] = '_', // <
+        [61] = '_', // =
+        [62] = '_', // >
+        [63] = '_', // ?
+        [64] = '_', // @
+        [65] = 'a', // A
+        [66] = 'b', // B
+        [67] = 'c', // C
+        [68] = 'd', // D
+        [69] = 'e', // E
+        [70] = 'f', // F
+        [71] = 'g', // G
+        [72] = 'h', // H
+        [73] = 'i', // I
+        [74] = 'j', // J
+        [75] = 'k', // K
+        [76] = 'l', // L
+        [77] = 'm', // M
+        [78] = 'n', // N
+        [79] = 'o', // O
+        [80] = 'p', // P
+        [81] = 'q', // Q
+        [82] = 'r', // R
+        [83] = 's', // S
+        [84] = 't', // T
+        [85] = 'u', // U
+        [86] = 'v', // V
+        [87] = 'w', // W
+        [88] = 'x', // X
+        [89] = 'y', // Y
+        [90] = 'z', // Z
+        [91] = '_', // [
+        [92] = '/', // backslash
+        [93] = '_', // ]
+        [94] = '_', // ^
+        [95] = '_', // _
+        [96] = '_', // `
+        [97] = 'a', // a
+        [98] = 'b', // b
+        [99] = 'c', // c
+        [100] = 'd', // d
+        [101] = 'e', // e
+        [102] = 'f', // f
+        [103] = 'g', // g
+        [104] = 'h', // h
+        [105] = 'i', // i
+        [106] = 'j', // j
+        [107] = 'k', // k
+        [108] = 'l', // l
+        [109] = 'm', // m
+        [110] = 'n', // n
+        [111] = 'o', // o
+        [112] = 'p', // p
+        [113] = 'q', // q
+        [114] = 'r', // r
+        [115] = 's', // s
+        [116] = 't', // t
+        [117] = 'u', // u
+        [118] = 'v', // v
+        [119] = 'w', // w
+        [120] = 'x', // x
+        [121] = 'y', // y
+        [122] = 'z', // z
+        [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] = '_'  //
+};
+
+// make sure the supplied string
+// is good for a netdata chart/dimension ID/NAME
+void netdata_fix_chart_name(char *s) {
+    while ((*s = netdata_map_chart_names[(unsigned char) *s])) s++;
+}
+
+unsigned char netdata_map_chart_ids[256] = {
+        [0] = '\0', //
+        [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] = '0', // 0
+        [49] = '1', // 1
+        [50] = '2', // 2
+        [51] = '3', // 3
+        [52] = '4', // 4
+        [53] = '5', // 5
+        [54] = '6', // 6
+        [55] = '7', // 7
+        [56] = '8', // 8
+        [57] = '9', // 9
+        [58] = '_', // :
+        [59] = '_', // ;
+        [60] = '_', // <
+        [61] = '_', // =
+        [62] = '_', // >
+        [63] = '_', // ?
+        [64] = '_', // @
+        [65] = 'a', // A
+        [66] = 'b', // B
+        [67] = 'c', // C
+        [68] = 'd', // D
+        [69] = 'e', // E
+        [70] = 'f', // F
+        [71] = 'g', // G
+        [72] = 'h', // H
+        [73] = 'i', // I
+        [74] = 'j', // J
+        [75] = 'k', // K
+        [76] = 'l', // L
+        [77] = 'm', // M
+        [78] = 'n', // N
+        [79] = 'o', // O
+        [80] = 'p', // P
+        [81] = 'q', // Q
+        [82] = 'r', // R
+        [83] = 's', // S
+        [84] = 't', // T
+        [85] = 'u', // U
+        [86] = 'v', // V
+        [87] = 'w', // W
+        [88] = 'x', // X
+        [89] = 'y', // Y
+        [90] = 'z', // Z
+        [91] = '_', // [
+        [92] = '/', // backslash
+        [93] = '_', // ]
+        [94] = '_', // ^
+        [95] = '_', // _
+        [96] = '_', // `
+        [97] = 'a', // a
+        [98] = 'b', // b
+        [99] = 'c', // c
+        [100] = 'd', // d
+        [101] = 'e', // e
+        [102] = 'f', // f
+        [103] = 'g', // g
+        [104] = 'h', // h
+        [105] = 'i', // i
+        [106] = 'j', // j
+        [107] = 'k', // k
+        [108] = 'l', // l
+        [109] = 'm', // m
+        [110] = 'n', // n
+        [111] = 'o', // o
+        [112] = 'p', // p
+        [113] = 'q', // q
+        [114] = 'r', // r
+        [115] = 's', // s
+        [116] = 't', // t
+        [117] = 'u', // u
+        [118] = 'v', // v
+        [119] = 'w', // w
+        [120] = 'x', // x
+        [121] = 'y', // y
+        [122] = 'z', // z
+        [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] = '_'  //
+};
+
+// make sure the supplied string
+// is good for a netdata chart/dimension ID/NAME
+void netdata_fix_chart_id(char *s) {
+    while ((*s = netdata_map_chart_ids[(unsigned char) *s])) s++;
+}
+
+/*
+// http://stackoverflow.com/questions/7666509/hash-function-for-string
+uint32_t simple_hash(const char *name)
+{
+    const char *s = name;
+    uint32_t hash = 5381;
+    int i;
+
+    while((i = *s++)) hash = ((hash << 5) + hash) + i;
+
+    // fprintf(stderr, "HASH: %lu %s\n", hash, name);
+
+    return hash;
+}
+*/
+
+/*
+// http://isthe.com/chongo/tech/comp/fnv/#FNV-1a
+uint32_t simple_hash(const char *name) {
+    unsigned char *s = (unsigned char *) name;
+    uint32_t hval = 0x811c9dc5;
+
+    // FNV-1a algorithm
+    while (*s) {
+        // multiply by the 32 bit FNV magic prime mod 2^32
+        // NOTE: No need to optimize with left shifts.
+        //       GCC will use imul instruction anyway.
+        //       Tested with 'gcc -O3 -S'
+        //hval += (hval<<1) + (hval<<4) + (hval<<7) + (hval<<8) + (hval<<24);
+        hval *= 16777619;
+
+        // xor the bottom with the current octet
+        hval ^= (uint32_t) *s++;
+    }
+
+    // fprintf(stderr, "HASH: %u = %s\n", hval, name);
+    return hval;
+}
+
+uint32_t simple_uhash(const char *name) {
+    unsigned char *s = (unsigned char *) name;
+    uint32_t hval = 0x811c9dc5, c;
+
+    // FNV-1a algorithm
+    while ((c = *s++)) {
+        if (unlikely(c >= 'A' && c <= 'Z')) c += 'a' - 'A';
+        hval *= 16777619;
+        hval ^= c;
+    }
+    return hval;
+}
+*/
+
+/*
+// http://eternallyconfuzzled.com/tuts/algorithms/jsw_tut_hashing.aspx
+// one at a time hash
+uint32_t simple_hash(const char *name) {
+    unsigned char *s = (unsigned char *)name;
+    uint32_t h = 0;
+
+    while(*s) {
+        h += *s++;
+        h += (h << 10);
+        h ^= (h >> 6);
+    }
+
+    h += (h << 3);
+    h ^= (h >> 11);
+    h += (h << 15);
+
+    // fprintf(stderr, "HASH: %u = %s\n", h, name);
+
+    return h;
+}
+*/
+
+void strreverse(char *begin, char *end) {
+    while (end > begin) {
+        // clearer code.
+        char aux = *end;
+        *end-- = *begin;
+        *begin++ = aux;
+    }
+}
+
+char *strsep_on_1char(char **ptr, char c) {
+    if(unlikely(!ptr || !*ptr))
+        return NULL;
+
+    // remember the position we started
+    char *s = *ptr;
+
+    // skip separators in front
+    while(*s == c) s++;
+    char *ret = s;
+
+    // find the next separator
+    while(*s++) {
+        if(unlikely(*s == c)) {
+            *s++ = '\0';
+            *ptr = s;
+            return ret;
+        }
+    }
+
+    *ptr = NULL;
+    return ret;
+}
+
+char *mystrsep(char **ptr, char *s) {
+    char *p = "";
+    while (p && !p[0] && *ptr) p = strsep(ptr, s);
+    return (p);
+}
+
+char *trim(char *s) {
+    // skip leading spaces
+    while (*s && isspace(*s)) s++;
+    if (!*s) return NULL;
+
+    // skip tailing spaces
+    // this way is way faster. Writes only one NUL char.
+    ssize_t l = strlen(s);
+    if (--l >= 0) {
+        char *p = s + l;
+        while (p > s && isspace(*p)) p--;
+        *++p = '\0';
+    }
+
+    if (!*s) return NULL;
+
+    return s;
+}
+
+inline char *trim_all(char *buffer) {
+    char *d = buffer, *s = buffer;
+
+    // skip spaces
+    while(isspace(*s)) s++;
+
+    while(*s) {
+        // copy the non-space part
+        while(*s && !isspace(*s)) *d++ = *s++;
+
+        // add a space if we have to
+        if(*s && isspace(*s)) {
+            *d++ = ' ';
+            s++;
+        }
+
+        // skip spaces
+        while(isspace(*s)) s++;
+    }
+
+    *d = '\0';
+
+    if(d > buffer) {
+        d--;
+        if(isspace(*d)) *d = '\0';
+    }
+
+    if(!buffer[0]) return NULL;
+    return buffer;
+}
+
+static int memory_file_open(const char *filename, size_t size) {
+    // info("memory_file_open('%s', %zu", filename, size);
+
+    int fd = open(filename, O_RDWR | O_CREAT | O_NOATIME, 0664);
+    if (fd != -1) {
+        if (lseek(fd, size, SEEK_SET) == (off_t) size) {
+            if (write(fd, "", 1) == 1) {
+                if (ftruncate(fd, size))
+                    error("Cannot truncate file '%s' to size %zu. Will use the larger file.", filename, size);
+            }
+            else error("Cannot write to file '%s' at position %zu.", filename, size);
+        }
+        else error("Cannot seek file '%s' to size %zu.", filename, size);
+    }
+    else error("Cannot create/open file '%s'.", filename);
+
+    return fd;
+}
+
+// mmap_shared is used for memory mode = map
+static void *memory_file_mmap(const char *filename, size_t size, int flags) {
+    // info("memory_file_mmap('%s', %zu", filename, size);
+    static int log_madvise = 1;
+
+    int fd = -1;
+    if(filename) {
+        fd = memory_file_open(filename, size);
+        if(fd == -1) return MAP_FAILED;
+    }
+
+    void *mem = mmap(NULL, size, PROT_READ | PROT_WRITE, flags, fd, 0);
+    if (mem != MAP_FAILED) {
+#ifdef NETDATA_LOG_ALLOCATIONS
+        mmap_accounting(size);
+#endif
+        int advise = MADV_SEQUENTIAL | MADV_DONTFORK;
+        if (flags & MAP_SHARED) advise |= MADV_WILLNEED;
+
+        if (madvise(mem, size, advise) != 0 && log_madvise) {
+            error("Cannot advise the kernel about shared memory usage.");
+            log_madvise--;
+        }
+    }
+
+    if(fd != -1)
+        close(fd);
+
+    return mem;
+}
+
+#ifdef MADV_MERGEABLE
+static void *memory_file_mmap_ksm(const char *filename, size_t size, int flags) {
+    // info("memory_file_mmap_ksm('%s', %zu", filename, size);
+    static int log_madvise_2 = 1, log_madvise_3 = 1;
+
+    int fd = -1;
+    if(filename) {
+        fd = memory_file_open(filename, size);
+        if(fd == -1) return MAP_FAILED;
+    }
+
+    void *mem = mmap(NULL, size, PROT_READ | PROT_WRITE, flags | MAP_ANONYMOUS, -1, 0);
+    if (mem != MAP_FAILED) {
+#ifdef NETDATA_LOG_ALLOCATIONS
+        mmap_accounting(size);
+#endif
+        if(fd != -1) {
+            if (lseek(fd, 0, SEEK_SET) == 0) {
+                if (read(fd, mem, size) != (ssize_t) size)
+                    error("Cannot read from file '%s'", filename);
+            }
+            else error("Cannot seek to beginning of file '%s'.", filename);
+        }
+
+        // don't use MADV_SEQUENTIAL|MADV_DONTFORK, they disable MADV_MERGEABLE
+        if (madvise(mem, size, MADV_SEQUENTIAL | MADV_DONTFORK) != 0 && log_madvise_2) {
+            error("Cannot advise the kernel about the memory usage (MADV_SEQUENTIAL|MADV_DONTFORK) of file '%s'.", filename);
+            log_madvise_2--;
+        }
+
+        if (madvise(mem, size, MADV_MERGEABLE) != 0 && log_madvise_3) {
+            error("Cannot advise the kernel about the memory usage (MADV_MERGEABLE) of file '%s'.", filename);
+            log_madvise_3--;
+        }
+    }
+
+    if(fd != -1)
+        close(fd);
+
+    return mem;
+}
+#else
+static void *memory_file_mmap_ksm(const char *filename, size_t size, int flags) {
+    // info("memory_file_mmap_ksm FALLBACK ('%s', %zu", filename, size);
+
+    if(filename)
+        return memory_file_mmap(filename, size, flags);
+
+    // when KSM is not available and no filename is given (memory mode = ram),
+    // we just report failure
+    return MAP_FAILED;
+}
+#endif
+
+void *mymmap(const char *filename, size_t size, int flags, int ksm) {
+    void *mem = NULL;
+
+    if (filename && (flags & MAP_SHARED || !enable_ksm || !ksm))
+        // memory mode = map | save
+        // when KSM is not enabled
+        // MAP_SHARED is used for memory mode = map (no KSM possible)
+        mem = memory_file_mmap(filename, size, flags);
+
+    else
+        // memory mode = save | ram
+        // when KSM is enabled
+        // for memory mode = ram, the filename is NULL
+        mem = memory_file_mmap_ksm(filename, size, flags);
+
+    if(mem == MAP_FAILED) return NULL;
+
+    errno = 0;
+    return mem;
+}
+
+int memory_file_save(const char *filename, void *mem, size_t size) {
+    char tmpfilename[FILENAME_MAX + 1];
+
+    snprintfz(tmpfilename, FILENAME_MAX, "%s.%ld.tmp", filename, (long) getpid());
+
+    int fd = open(tmpfilename, O_RDWR | O_CREAT | O_NOATIME, 0664);
+    if (fd < 0) {
+        error("Cannot create/open file '%s'.", filename);
+        return -1;
+    }
+
+    if (write(fd, mem, size) != (ssize_t) size) {
+        error("Cannot write to file '%s' %ld bytes.", filename, (long) size);
+        close(fd);
+        return -1;
+    }
+
+    close(fd);
+
+    if (rename(tmpfilename, filename)) {
+        error("Cannot rename '%s' to '%s'", tmpfilename, filename);
+        return -1;
+    }
+
+    return 0;
+}
+
+int fd_is_valid(int fd) {
+    return fcntl(fd, F_GETFD) != -1 || errno != EBADF;
+}
+
+char *fgets_trim_len(char *buf, size_t buf_size, FILE *fp, size_t *len) {
+    char *s = fgets(buf, (int)buf_size, fp);
+    if (!s) return NULL;
+
+    char *t = s;
+    if (*t != '\0') {
+        // find the string end
+        while (*++t != '\0');
+
+        // trim trailing spaces/newlines/tabs
+        while (--t > s && *t == '\n')
+            *t = '\0';
+    }
+
+    if (len)
+        *len = t - s + 1;
+
+    return s;
+}
+
+int vsnprintfz(char *dst, size_t n, const char *fmt, va_list args) {
+    int size = vsnprintf(dst, n, fmt, args);
+
+    if (unlikely((size_t) size > n)) {
+        // truncated
+        size = (int)n;
+    }
+
+    dst[size] = '\0';
+    return size;
+}
+
+int snprintfz(char *dst, size_t n, const char *fmt, ...) {
+    va_list args;
+
+    va_start(args, fmt);
+    int ret = vsnprintfz(dst, n, fmt, args);
+    va_end(args);
+
+    return ret;
+}
+
+/*
+// poor man cycle counting
+static unsigned long tsc;
+void begin_tsc(void) {
+    unsigned long a, d;
+    asm volatile ("cpuid\nrdtsc" : "=a" (a), "=d" (d) : "0" (0) : "ebx", "ecx");
+    tsc = ((unsigned long)d << 32) | (unsigned long)a;
+}
+unsigned long end_tsc(void) {
+    unsigned long a, d;
+    asm volatile ("rdtscp" : "=a" (a), "=d" (d) : : "ecx");
+    return (((unsigned long)d << 32) | (unsigned long)a) - tsc;
+}
+*/
+
+int recursively_delete_dir(const char *path, const char *reason) {
+    DIR *dir = opendir(path);
+    if(!dir) {
+        error("Cannot read %s directory to be deleted '%s'", reason?reason:"", path);
+        return -1;
+    }
+
+    int ret = 0;
+    struct dirent *de = NULL;
+    while((de = readdir(dir))) {
+        if(de->d_type == DT_DIR
+           && (
+                   (de->d_name[0] == '.' && de->d_name[1] == '\0')
+                   || (de->d_name[0] == '.' && de->d_name[1] == '.' && de->d_name[2] == '\0')
+           ))
+            continue;
+
+        char fullpath[FILENAME_MAX + 1];
+        snprintfz(fullpath, FILENAME_MAX, "%s/%s", path, de->d_name);
+
+        if(de->d_type == DT_DIR) {
+            int r = recursively_delete_dir(fullpath, reason);
+            if(r > 0) ret += r;
+            continue;
+        }
+
+        info("Deleting %s file '%s'", reason?reason:"", fullpath);
+        if(unlikely(unlink(fullpath) == -1))
+            error("Cannot delete %s file '%s'", reason?reason:"", fullpath);
+        else
+            ret++;
+    }
+
+    info("Deleting empty directory '%s'", path);
+    if(unlikely(rmdir(path) == -1))
+        error("Cannot delete empty directory '%s'", path);
+    else
+        ret++;
+
+    closedir(dir);
+
+    return ret;
+}
+
+static int is_virtual_filesystem(const char *path, char **reason) {
+
+#if defined(__APPLE__) || defined(__FreeBSD__)
+    (void)path;
+    (void)reason;
+#else
+    struct statfs stat;
+    // stat.f_fsid.__val[0] is a file system id
+    // stat.f_fsid.__val[1] is the inode
+    // so their combination uniquely identifies the file/dir
+
+    if (statfs(path, &stat) == -1) {
+        if(reason) *reason = "failed to statfs()";
+        return -1;
+    }
+
+    if(stat.f_fsid.__val[0] != 0 || stat.f_fsid.__val[1] != 0) {
+        errno = EINVAL;
+        if(reason) *reason = "is not a virtual file system";
+        return -1;
+    }
+#endif
+
+    return 0;
+}
+
+int verify_netdata_host_prefix() {
+    if(!netdata_configured_host_prefix)
+        netdata_configured_host_prefix = "";
+
+    if(!*netdata_configured_host_prefix)
+        return 0;
+
+    char buffer[FILENAME_MAX + 1];
+    char *path = netdata_configured_host_prefix;
+    char *reason = "unknown reason";
+    errno = 0;
+
+    struct stat sb;
+    if (stat(path, &sb) == -1) {
+        reason = "failed to stat()";
+        goto failed;
+    }
+
+    if((sb.st_mode & S_IFMT) != S_IFDIR) {
+        errno = EINVAL;
+        reason = "is not a directory";
+        goto failed;
+    }
+
+    path = buffer;
+    snprintfz(path, FILENAME_MAX, "%s/proc", netdata_configured_host_prefix);
+    if(is_virtual_filesystem(path, &reason) == -1)
+        goto failed;
+
+    snprintfz(path, FILENAME_MAX, "%s/sys", netdata_configured_host_prefix);
+    if(is_virtual_filesystem(path, &reason) == -1)
+        goto failed;
+
+    if(netdata_configured_host_prefix && *netdata_configured_host_prefix)
+        info("Using host prefix directory '%s'", netdata_configured_host_prefix);
+
+    return 0;
+
+failed:
+    error("Ignoring host prefix '%s': path '%s' %s", netdata_configured_host_prefix, path, reason);
+    netdata_configured_host_prefix = "";
+    return -1;
+}
+
+char *strdupz_path_subpath(const char *path, const char *subpath) {
+    if(unlikely(!path || !*path)) path = ".";
+    if(unlikely(!subpath)) subpath = "";
+
+    // skip trailing slashes in path
+    size_t len = strlen(path);
+    while(len > 0 && path[len - 1] == '/') len--;
+
+    // skip leading slashes in subpath
+    while(subpath[0] == '/') subpath++;
+
+    // if the last character in path is / and (there is a subpath or path is now empty)
+    // keep the trailing slash in path and remove the additional slash
+    char *slash = "/";
+    if(path[len] == '/' && (*subpath || len == 0)) {
+        slash = "";
+        len++;
+    }
+    else if(!*subpath) {
+        // there is no subpath
+        // no need for trailing slash
+        slash = "";
+    }
+
+    char buffer[FILENAME_MAX + 1];
+    snprintfz(buffer, FILENAME_MAX, "%.*s%s%s", (int)len, path, slash, subpath);
+    return strdupz(buffer);
+}
+
+int path_is_dir(const char *path, const char *subpath) {
+    char *s = strdupz_path_subpath(path, subpath);
+
+    size_t max_links = 100;
+
+    int is_dir = 0;
+    struct stat statbuf;
+    while(max_links-- && stat(s, &statbuf) == 0) {
+        if((statbuf.st_mode & S_IFMT) == S_IFDIR) {
+            is_dir = 1;
+            break;
+        }
+        else if((statbuf.st_mode & S_IFMT) == S_IFLNK) {
+            char buffer[FILENAME_MAX + 1];
+            ssize_t l = readlink(s, buffer, FILENAME_MAX);
+            if(l > 0) {
+                buffer[l] = '\0';
+                freez(s);
+                s = strdupz(buffer);
+                continue;
+            }
+            else {
+                is_dir = 0;
+                break;
+            }
+        }
+        else {
+            is_dir = 0;
+            break;
+        }
+    }
+
+    freez(s);
+    return is_dir;
+}
+
+int path_is_file(const char *path, const char *subpath) {
+    char *s = strdupz_path_subpath(path, subpath);
+
+    size_t max_links = 100;
+
+    int is_file = 0;
+    struct stat statbuf;
+    while(max_links-- && stat(s, &statbuf) == 0) {
+        if((statbuf.st_mode & S_IFMT) == S_IFREG) {
+            is_file = 1;
+            break;
+        }
+        else if((statbuf.st_mode & S_IFMT) == S_IFLNK) {
+            char buffer[FILENAME_MAX + 1];
+            ssize_t l = readlink(s, buffer, FILENAME_MAX);
+            if(l > 0) {
+                buffer[l] = '\0';
+                freez(s);
+                s = strdupz(buffer);
+                continue;
+            }
+            else {
+                is_file = 0;
+                break;
+            }
+        }
+        else {
+            is_file = 0;
+            break;
+        }
+    }
+
+    freez(s);
+    return is_file;
+}
+
+void recursive_config_double_dir_load(const char *user_path, const char *stock_path, const char *subpath, int (*callback)(const char *filename, void *data), void *data, size_t depth) {
+    if(depth > 3) {
+        error("CONFIG: Max directory depth reached while reading user path '%s', stock path '%s', subpath '%s'", user_path, stock_path, subpath);
+        return;
+    }
+
+    char *udir = strdupz_path_subpath(user_path, subpath);
+    char *sdir = strdupz_path_subpath(stock_path, subpath);
+
+    debug(D_HEALTH, "CONFIG traversing user-config directory '%s', stock config directory '%s'", udir, sdir);
+
+    DIR *dir = opendir(udir);
+    if (!dir) {
+        error("CONFIG cannot open user-config directory '%s'.", udir);
+    }
+    else {
+        struct dirent *de = NULL;
+        while((de = readdir(dir))) {
+            if(de->d_type == DT_DIR || de->d_type == DT_LNK) {
+                if( !de->d_name[0] ||
+                    (de->d_name[0] == '.' && de->d_name[1] == '\0') ||
+                    (de->d_name[0] == '.' && de->d_name[1] == '.' && de->d_name[2] == '\0')
+                        ) {
+                    debug(D_HEALTH, "CONFIG ignoring user-config directory '%s/%s'", udir, de->d_name);
+                    continue;
+                }
+
+                if(path_is_dir(udir, de->d_name)) {
+                    recursive_config_double_dir_load(udir, sdir, de->d_name, callback, data, depth + 1);
+                    continue;
+                }
+            }
+
+            if(de->d_type == DT_UNKNOWN || de->d_type == DT_REG || de->d_type == DT_LNK) {
+                size_t len = strlen(de->d_name);
+                if(path_is_file(udir, de->d_name) &&
+                   len > 5 && !strcmp(&de->d_name[len - 5], ".conf")) {
+                    char *filename = strdupz_path_subpath(udir, de->d_name);
+                    debug(D_HEALTH, "CONFIG calling callback for user file '%s'", filename);
+                    callback(filename, data);
+                    freez(filename);
+                    continue;
+                }
+            }
+
+            debug(D_HEALTH, "CONFIG ignoring user-config file '%s/%s' of type %d", udir, de->d_name, (int)de->d_type);
+        }
+
+        closedir(dir);
+    }
+
+    debug(D_HEALTH, "CONFIG traversing stock config directory '%s', user config directory '%s'", sdir, udir);
+
+    dir = opendir(sdir);
+    if (!dir) {
+        error("CONFIG cannot open stock config directory '%s'.", sdir);
+    }
+    else {
+        struct dirent *de = NULL;
+        while((de = readdir(dir))) {
+            if(de->d_type == DT_DIR || de->d_type == DT_LNK) {
+                if( !de->d_name[0] ||
+                    (de->d_name[0] == '.' && de->d_name[1] == '\0') ||
+                    (de->d_name[0] == '.' && de->d_name[1] == '.' && de->d_name[2] == '\0')
+                        ) {
+                    debug(D_HEALTH, "CONFIG ignoring stock config directory '%s/%s'", sdir, de->d_name);
+                    continue;
+                }
+
+                if(path_is_dir(sdir, de->d_name)) {
+                    // we recurse in stock subdirectory, only when there is no corresponding
+                    // user subdirectory - to avoid reading the files twice
+
+                    if(!path_is_dir(udir, de->d_name))
+                        recursive_config_double_dir_load(udir, sdir, de->d_name, callback, data, depth + 1);
+
+                    continue;
+                }
+            }
+
+            if(de->d_type == DT_UNKNOWN || de->d_type == DT_REG || de->d_type == DT_LNK) {
+                size_t len = strlen(de->d_name);
+                if(path_is_file(sdir, de->d_name) && !path_is_file(udir, de->d_name) &&
+                   len > 5 && !strcmp(&de->d_name[len - 5], ".conf")) {
+                    char *filename = strdupz_path_subpath(sdir, de->d_name);
+                    debug(D_HEALTH, "CONFIG calling callback for stock file '%s'", filename);
+                    callback(filename, data);
+                    freez(filename);
+                    continue;
+                }
+
+            }
+
+            debug(D_HEALTH, "CONFIG ignoring stock-config file '%s/%s' of type %d", udir, de->d_name, (int)de->d_type);
+        }
+
+        closedir(dir);
+    }
+
+    debug(D_HEALTH, "CONFIG done traversing user-config directory '%s', stock config directory '%s'", udir, sdir);
+
+    freez(udir);
+    freez(sdir);
+}