15150396955

Committed 20 May 2025 10:32PM UTC coverage: 72.047% (-0.2%) from 72.25%

Build # 15150396955

Build Type

push

github

Committed by

web-flow

Commit Message

resolved: add new "DNS Delegate" concepts (#34368)

Various long standing issues (at least: #5573 #14159 #20485 #21260
#24532 #32022 #18056) have been asking for a way to delegate DNS
resolution of specific domains to very specific DNS servers.

This PR goes a major step towards that goal by adding a new concept "DNS
Delegate" which allows to configure just that. Basically, this adds a
third kind of DNS scope to resolved's logic: besides the per-link and
global DNS scopes there are now also "delegate" scopes, which can be
created by dropping in a new file /etc/systemd/dns-delegate/*.conf. They
carry DNS= and Domains= lines just like the global setting or what the
per-link configuration can carry.

And they are consulted the same way as link DNS scopes are considered,
following the same routing rules.

This allows to configure these DNS delegates statically via drop-in
files as mentioned, and only adds the most basic functionality. Later on
we might want to extend this:

1. Allow dynamic creation of DNS delegates via IPC with lifecycle bound
to IPC client (usecase: installing a DNS delegate that routes traffic to
some DNS-over-TLS server once basic setup is complete).
2. Allow configuration of protocol details per delegate the same way
this is currently allowed per-link.
3. Instead of strictly using DNS as delegation protocol, support an
alternative varlink based protocol (without retransmission problems and
so on) that systemd-machined and similar can implement.

This PR is not complete yet. Lacks docs and tests. Seems to work fine in
my local tests however.

Fixes: #5573
Fixes: #18056
Fixes: #20485

Run Details

470 of 586 new or added lines in 14 files covered. (80.2%)

3358 existing lines in 54 files now uncovered.

299091 of 415134 relevant lines covered (72.05%)

703065.7 hits per line

Source File
Press 'n' to go to next uncovered line, 'b' for previous

91.03

/src/basic/string-util.c

/* SPDX-License-Identifier: LGPL-2.1-or-later */

#include <errno.h>
#include <stdarg.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>

#include "alloc-util.h"
#include "escape.h"
#include "extract-word.h"
#include "fd-util.h"
#include "fileio.h"
#include "glyph-util.h"
#include "gunicode.h"
#include "locale-util.h"
#include "log.h"
#include "macro.h"
#include "memory-util.h"
#include "memstream-util.h"
#include "path-util.h"
#include "string-util.h"
#include "strv.h"
#include "terminal-util.h"
#include "utf8.h"

char* first_word(const char *s, const char *word) {
        assert(s);
        assert(word);

        /* Checks if the string starts with the specified word, either followed by NUL or by whitespace.
         * Returns a pointer to the NUL or the first character after the whitespace. */

        if (isempty(word))
                return (char*) s;

        const char *p = startswith(s, word);
        if (!p)
                return NULL;
        if (*p == '\0')
                return (char*) p;

        const char *nw = skip_leading_chars(p, WHITESPACE);
        if (p == nw)
                return NULL;

        return (char*) nw;
}

char* strprepend(char **x, const char *s) {
        assert(x);

        if (isempty(s) && *x)
                return *x;

        char *p = strjoin(strempty(s), *x);
        if (!p)
                return NULL;

        free_and_replace(*x, p);
        return *x;
}

char* strextendn(char **x, const char *s, size_t l) {
        assert(x);
        assert(s || l == 0);

        if (l > 0)
                l = strnlen(s, l); /* ignore trailing noise */

        if (l > 0 || !*x) {
                size_t q;
                char *m;

                q = strlen_ptr(*x);
                m = realloc(*x, q + l + 1);
                if (!m)
                        return NULL;

                *mempcpy_typesafe(m + q, s, l) = 0;

                *x = m;
        }

        return *x;
}

char* strstrip(char *s) {
        if (!s)
                return NULL;

        /* Drops trailing whitespace. Modifies the string in place. Returns pointer to first non-space character */

        return delete_trailing_chars(skip_leading_chars(s, WHITESPACE), WHITESPACE);
}

char* delete_chars(char *s, const char *bad) {
        char *f, *t;

        /* Drops all specified bad characters, regardless where in the string */

        if (!s)
                return NULL;

        if (!bad)
                bad = WHITESPACE;

        for (f = s, t = s; *f; f++) {
                if (strchr(bad, *f))
                        continue;

                *(t++) = *f;
        }

        *t = 0;

        return s;
}

char* delete_trailing_chars(char *s, const char *bad) {
        char *c = s;

        /* Drops all specified bad characters, at the end of the string */

        if (!s)
                return NULL;

        if (!bad)
                bad = WHITESPACE;

        for (char *p = s; *p; p++)
                if (!strchr(bad, *p))
                        c = p + 1;

        *c = 0;

        return s;
}

char* truncate_nl_full(char *s, size_t *ret_len) {
        size_t n;

        assert(s);

        n = strcspn(s, NEWLINE);
        s[n] = '\0';
        if (ret_len)
                *ret_len = n;
        return s;
}

char ascii_tolower(char x) {

        if (x >= 'A' && x <= 'Z')
                return x - 'A' + 'a';

        return x;
}

char ascii_toupper(char x) {

        if (x >= 'a' && x <= 'z')
                return x - 'a' + 'A';

        return x;
}

char* ascii_strlower(char *t) {
        assert(t);

        for (char *p = t; *p; p++)
                *p = ascii_tolower(*p);

        return t;
}

char* ascii_strupper(char *t) {
        assert(t);

        for (char *p = t; *p; p++)
                *p = ascii_toupper(*p);

        return t;
}

char* ascii_strlower_n(char *t, size_t n) {
        if (n <= 0)
                return t;

        for (size_t i = 0; i < n; i++)
                t[i] = ascii_tolower(t[i]);

        return t;
}

int ascii_strcasecmp_n(const char *a, const char *b, size_t n) {

        for (; n > 0; a++, b++, n--) {
                int x, y;

                x = (int) (uint8_t) ascii_tolower(*a);
                y = (int) (uint8_t) ascii_tolower(*b);

                if (x != y)
                        return x - y;
        }

        return 0;
}

int ascii_strcasecmp_nn(const char *a, size_t n, const char *b, size_t m) {
        int r;

        r = ascii_strcasecmp_n(a, b, MIN(n, m));
        if (r != 0)
                return r;

        return CMP(n, m);
}

bool chars_intersect(const char *a, const char *b) {
        /* Returns true if any of the chars in a are in b. */
        for (const char *p = a; *p; p++)
                if (strchr(b, *p))
                        return true;

        return false;
}

bool string_has_cc(const char *p, const char *ok) {
        assert(p);

        /*
         * Check if a string contains control characters. If 'ok' is
         * non-NULL it may be a string containing additional CCs to be
         * considered OK.
         */

        for (const char *t = p; *t; t++) {
                if (ok && strchr(ok, *t))
                        continue;

                if (char_is_cc(*t))
                        return true;
        }

        return false;
}

static int write_ellipsis(char *buf, bool unicode) {
        const char *s = glyph_full(GLYPH_ELLIPSIS, unicode);
        assert(strlen(s) == 3);
        memcpy(buf, s, 3);
        return 3;
}

static size_t ansi_sequence_length(const char *s, size_t len) {
        assert(s);

        if (len < 2)
                return 0;

        if (s[0] != 0x1B)  /* ASCII 27, aka ESC, aka Ctrl-[ */
                return 0;  /* Not the start of a sequence */

        if (s[1] == 0x5B) { /* [, start of CSI sequence */
                size_t i = 2;

                if (i == len)
                        return 0;

                while (s[i] >= 0x30 && s[i] <= 0x3F) /* Parameter bytes */
                        if (++i == len)
                                return 0;
                while (s[i] >= 0x20 && s[i] <= 0x2F) /* Intermediate bytes */
                        if (++i == len)
                                return 0;
                if (s[i] >= 0x40 && s[i] <= 0x7E) /* Final byte */
                        return i + 1;
                return 0;  /* Bad sequence */

        } else if (s[1] >= 0x40 && s[1] <= 0x5F) /* other non-CSI Fe sequence */
                return 2;

        return 0;  /* Bad escape? */
}

static bool string_has_ansi_sequence(const char *s, size_t len) {
        const char *t = s;

        while ((t = memchr(s, 0x1B, len - (t - s))))
                if (ansi_sequence_length(t, len - (t - s)) > 0)
                        return true;
        return false;
}

static size_t previous_ansi_sequence(const char *s, size_t length, const char **ret_where) {
        /* Locate the previous ANSI sequence and save its start in *ret_where and return length. */

        for (size_t i = length - 2; i > 0; i--) {  /* -2 because at least two bytes are needed */
                size_t slen = ansi_sequence_length(s + (i - 1), length - (i - 1));
                if (slen == 0)
                        continue;

                *ret_where = s + (i - 1);
                return slen;
        }

        *ret_where = NULL;
        return 0;
}

static char *ascii_ellipsize_mem(const char *s, size_t old_length, size_t new_length, unsigned percent) {
        size_t x, need_space, suffix_len;
        char *t;

        assert(s);
        assert(percent <= 100);
        assert(new_length != SIZE_MAX);

        if (old_length <= new_length)
                return strndup(s, old_length);

        /* Special case short ellipsations */
        switch (new_length) {

        case 0:
                return strdup("");

        case 1:
                if (is_locale_utf8())
                        return strdup("…");
                else
                        return strdup(".");

        case 2:
                if (!is_locale_utf8())
                        return strdup("..");
                break;
        }

        /* Calculate how much space the ellipsis will take up. If we are in UTF-8 mode we only need space for one
         * character ("…"), otherwise for three characters ("..."). Note that in both cases we need 3 bytes of storage,
         * either for the UTF-8 encoded character or for three ASCII characters. */
        need_space = is_locale_utf8() ? 1 : 3;

        t = new(char, new_length+3);
        if (!t)
                return NULL;

        assert(new_length >= need_space);

        x = ((new_length - need_space) * percent + 50) / 100;
        assert(x <= new_length - need_space);

        write_ellipsis(mempcpy(t, s, x), /* unicode = */ false);
        suffix_len = new_length - x - need_space;
        memcpy(t + x + 3, s + old_length - suffix_len, suffix_len);
        *(t + x + 3 + suffix_len) = '\0';

        return t;
}

char* ellipsize_mem(const char *s, size_t old_length, size_t new_length, unsigned percent) {
        size_t x, k, len, len2;
        const char *i, *j;
        int r;

        /* Note that 'old_length' refers to bytes in the string, while 'new_length' refers to character cells taken up
         * on screen. This distinction doesn't matter for ASCII strings, but it does matter for non-ASCII UTF-8
         * strings.
         *
         * Ellipsation is done in a locale-dependent way:
         * 1. If the string passed in is fully ASCII and the current locale is not UTF-8, three dots are used ("...")
         * 2. Otherwise, a unicode ellipsis is used ("…")
         *
         * In other words: you'll get a unicode ellipsis as soon as either the string contains non-ASCII characters or
         * the current locale is UTF-8.
         */

        assert(s);
        assert(percent <= 100);

        if (new_length == SIZE_MAX)
                return strndup(s, old_length);

        if (new_length == 0)
                return strdup("");

        bool has_ansi_seq = string_has_ansi_sequence(s, old_length);

        /* If no multibyte characters or ANSI sequences, use ascii_ellipsize_mem for speed */
        if (!has_ansi_seq && ascii_is_valid_n(s, old_length))
                return ascii_ellipsize_mem(s, old_length, new_length, percent);

        x = (new_length - 1) * percent / 100;
        assert(x <= new_length - 1);

        k = 0;
        for (i = s; i < s + old_length; ) {
                size_t slen = has_ansi_seq ? ansi_sequence_length(i, old_length - (i - s)) : 0;
                if (slen > 0) {
                        i += slen;
                        continue;  /* ANSI sequences don't take up any space in output */
                }

                char32_t c;
                r = utf8_encoded_to_unichar(i, &c);
                if (r < 0)
                        return NULL;

                int w = unichar_iswide(c) ? 2 : 1;
                if (k + w > x)
                        break;

                k += w;
                i += r;
        }

        const char *ansi_start = s + old_length;
        size_t ansi_len = 0;

        for (const char *t = j = s + old_length; t > i && k < new_length; ) {
                char32_t c;
                int w;
                const char *tt;

                if (has_ansi_seq && ansi_start >= t)
                        /* Figure out the previous ANSI sequence, if any */
                        ansi_len = previous_ansi_sequence(s, t - s, &ansi_start);

                /* If the sequence extends all the way to the current position, skip it. */
                if (has_ansi_seq && ansi_len > 0 && ansi_start + ansi_len == t) {
                        t = ansi_start;
                        continue;
                }

                tt = utf8_prev_char(t);
                r = utf8_encoded_to_unichar(tt, &c);
                if (r < 0)
                        return NULL;

                w = unichar_iswide(c) ? 2 : 1;
                if (k + w > new_length)
                        break;

                k += w;
                j = t = tt;  /* j should always point to the first "real" character */
        }

        /* We don't actually need to ellipsize */
        if (i >= j)
                return memdup_suffix0(s, old_length);

        if (k >= new_length) {
                /* Make space for ellipsis, if required and possible. We know that the edge character is not
                 * part of an ANSI sequence (because then we'd skip it). If the last character we looked at
                 * was wide, we don't need to make space. */
                if (j < s + old_length)
                        j = utf8_next_char(j);
                else if (i > s)
                        i = utf8_prev_char(i);
        }

        len = i - s;
        len2 = s + old_length - j;

        /* If we have ANSI, allow the same length as the source string + ellipsis. It'd be too involved to
         * figure out what exact space is needed. Strings with ANSI sequences are most likely to be fairly
         * short anyway. */
        size_t alloc_len = has_ansi_seq ? old_length + 3 + 1 : len + 3 + len2 + 1;

        char *e = new(char, alloc_len);
        if (!e)
                return NULL;

        memcpy_safe(e, s, len);
        write_ellipsis(e + len, /* unicode = */ true);

        char *dst = e + len + 3;

        if (has_ansi_seq)
                /* Copy over any ANSI sequences in full */
                for (const char *p = s + len; p < j; ) {
                        size_t slen = ansi_sequence_length(p, j - p);
                        if (slen > 0) {
                                dst = mempcpy(dst, p, slen);
                                p += slen;
                        } else
                                p = utf8_next_char(p);
                }

        memcpy_safe(dst, j, len2);
        dst[len2] = '\0';

        return e;
}

char* cellescape(char *buf, size_t len, const char *s) {
        /* Escape and ellipsize s into buffer buf of size len. Only non-control ASCII
         * characters are copied as they are, everything else is escaped. The result
         * is different then if escaping and ellipsization was performed in two
         * separate steps, because each sequence is either stored in full or skipped.
         *
         * This function should be used for logging about strings which expected to
         * be plain ASCII in a safe way.
         *
         * An ellipsis will be used if s is too long. It was always placed at the
         * very end.
         */

        size_t i = 0, last_char_width[4] = {}, k = 0;

        assert(buf);
        assert(len > 0); /* at least a terminating NUL */
        assert(s);

        for (;;) {
                char four[4];
                int w;

                if (*s == 0) /* terminating NUL detected? then we are done! */
                        goto done;

                w = cescape_char(*s, four);
                if (i + w + 1 > len) /* This character doesn't fit into the buffer anymore? In that case let's
                                      * ellipsize at the previous location */
                        break;

                /* OK, there was space, let's add this escaped character to the buffer */
                memcpy(buf + i, four, w);
                i += w;

                /* And remember its width in the ring buffer */
                last_char_width[k] = w;
                k = (k + 1) % 4;

                s++;
        }

        /* Ellipsation is necessary. This means we might need to truncate the string again to make space for 4
         * characters ideally, but the buffer is shorter than that in the first place take what we can get */
        for (size_t j = 0; j < ELEMENTSOF(last_char_width); j++) {

                if (i + 4 <= len) /* nice, we reached our space goal */
                        break;

                k = k == 0 ? 3 : k - 1;
                if (last_char_width[k] == 0) /* bummer, we reached the beginning of the strings */
                        break;

                assert(i >= last_char_width[k]);
                i -= last_char_width[k];
        }

        if (i + 4 <= len) /* yay, enough space */
                i += write_ellipsis(buf + i, /* unicode = */ false);
        else if (i + 3 <= len) { /* only space for ".." */
                buf[i++] = '.';
                buf[i++] = '.';
        } else if (i + 2 <= len) /* only space for a single "." */
                buf[i++] = '.';
        else
                assert(i + 1 <= len);

done:
        buf[i] = '\0';
        return buf;
}

char* strshorten(char *s, size_t l) {
        assert(s);

        if (l >= SIZE_MAX-1) /* Would not change anything */
                return s;

        if (strnlen(s, l+1) > l)
                s[l] = 0;

        return s;
}

int strgrowpad0(char **s, size_t l) {
        size_t sz;

        assert(s);

        if (*s) {
                sz = strlen(*s) + 1;
                if (sz >= l) /* never shrink */
                        return 0;
        } else
                sz = 0;

        char *q = realloc(*s, l);
        if (!q)
                return -ENOMEM;

        *s = q;

        memzero(*s + sz, l - sz);
        return 0;
}

char* strreplace(const char *text, const char *old_string, const char *new_string) {
        size_t l, old_len, new_len;
        char *t, *ret = NULL;
        const char *f;

        assert(old_string);
        assert(new_string);

        if (!text)
                return NULL;

        old_len = strlen(old_string);
        new_len = strlen(new_string);

        l = strlen(text);
        if (!GREEDY_REALLOC(ret, l+1))
                return NULL;

        f = text;
        t = ret;
        while (*f) {
                size_t d, nl;

                if (!startswith(f, old_string)) {
                        *(t++) = *(f++);
                        continue;
                }

                d = t - ret;
                nl = l - old_len + new_len;

                if (!GREEDY_REALLOC(ret, nl + 1))
                        return mfree(ret);

                l = nl;
                t = ret + d;

                t = stpcpy(t, new_string);
                f += old_len;
        }

        *t = 0;
        return ret;
}

static void advance_offsets(
                ssize_t diff,
                size_t offsets[2], /* note: we can't use [static 2] here, since this may be NULL */
                size_t shift[static 2],
                size_t size) {

        if (!offsets)
                return;

        assert(shift);

        if ((size_t) diff < offsets[0])
                shift[0] += size;
        if ((size_t) diff < offsets[1])
                shift[1] += size;
}

char* strip_tab_ansi(char **ibuf, size_t *_isz, size_t highlight[2]) {
        const char *begin = NULL;
        enum {
                STATE_OTHER,
                STATE_ESCAPE,
                STATE_CSI,
                STATE_OSC,
                STATE_OSC_CLOSING,
        } state = STATE_OTHER;
        _cleanup_(memstream_done) MemStream m = {};
        size_t isz, shift[2] = {}, n_carriage_returns = 0;
        FILE *f;

        assert(ibuf);
        assert(*ibuf);

        /* This does three things:
         *
         * 1. Replaces TABs by 8 spaces
         * 2. Strips ANSI color sequences (a subset of CSI), i.e. ESC '[' … 'm' sequences
         * 3. Strips ANSI operating system sequences (OSC), i.e. ESC ']' … ST sequences
         * 4. Strip trailing \r characters (since they would "move the cursor", but have no
         *    other effect).
         *
         * Everything else will be left as it is. In particular other ANSI sequences are left as they are, as
         * are any other special characters. Truncated ANSI sequences are left-as is too. This call is
         * supposed to suppress the most basic formatting noise, but nothing else.
         *
         * Why care for OSC sequences? Well, to undo what terminal_urlify() and friends generate. */

        isz = _isz ? *_isz : strlen(*ibuf);

        /* Note we turn off internal locking on f for performance reasons. It's safe to do so since we
         * created f here and it doesn't leave our scope. */
        f = memstream_init(&m);
        if (!f)
                return NULL;

        for (const char *i = *ibuf; i < *ibuf + isz + 1; i++) {

                bool eot = i >= *ibuf + isz;

                switch (state) {

                case STATE_OTHER:
                        if (eot)
                                break;

                        if (*i == '\r') {
                                n_carriage_returns++;
                                break;
                        } else if (*i == '\n')
                                /* Ignore carriage returns before new line */
                                n_carriage_returns = 0;
                        for (; n_carriage_returns > 0; n_carriage_returns--)
                                fputc('\r', f);

                        if (*i == '\x1B')
                                state = STATE_ESCAPE;
                        else if (*i == '\t') {
                                fputs("        ", f);
                                advance_offsets(i - *ibuf, highlight, shift, 7);
                        } else
                                fputc(*i, f);

                        break;

                case STATE_ESCAPE:
                        assert(n_carriage_returns == 0);

                        if (eot) {
                                fputc('\x1B', f);
                                advance_offsets(i - *ibuf, highlight, shift, 1);
                                break;
                        } else if (*i == '[') { /* ANSI CSI */
                                state = STATE_CSI;
                                begin = i + 1;
                        } else if (*i == ']') { /* ANSI OSC */
                                state = STATE_OSC;
                                begin = i + 1;
                        } else {
                                fputc('\x1B', f);
                                fputc(*i, f);
                                advance_offsets(i - *ibuf, highlight, shift, 1);
                                state = STATE_OTHER;
                        }

                        break;

                case STATE_CSI:
                        assert(n_carriage_returns == 0);

                        if (eot || !strchr("01234567890;m", *i)) { /* EOT or invalid chars in sequence */
                                fputc('\x1B', f);
                                fputc('[', f);
                                advance_offsets(i - *ibuf, highlight, shift, 2);
                                state = STATE_OTHER;
                                i = begin-1;
                        } else if (*i == 'm')
                                state = STATE_OTHER;

                        break;

                case STATE_OSC:
                        assert(n_carriage_returns == 0);

                        /* There are three kinds of OSC terminators: \x07, \x1b\x5c or \x9c. We only support
                         * the first two, because the last one is a valid UTF-8 codepoint and hence creates
                         * an ambiguity (many Terminal emulators refuse to support it as well). */
                        if (eot || (!IN_SET(*i, '\x07', '\x1b') && !osc_char_is_valid(*i))) { /* EOT or invalid chars in sequence */
                                fputc('\x1B', f);
                                fputc(']', f);
                                advance_offsets(i - *ibuf, highlight, shift, 2);
                                state = STATE_OTHER;
                                i = begin-1;
                        } else if (*i == '\x07') /* Single character ST */
                                state = STATE_OTHER;
                        else if (*i == '\x1B')
                                state = STATE_OSC_CLOSING;

                        break;

                case STATE_OSC_CLOSING:
                        if (eot || *i != '\x5c') { /* EOT or incomplete two-byte ST in sequence */
                                fputc('\x1B', f);
                                fputc(']', f);
                                advance_offsets(i - *ibuf, highlight, shift, 2);
                                state = STATE_OTHER;
                                i = begin-1;
                        } else if (*i == '\x5c')
                                state = STATE_OTHER;

                        break;
                }
        }

        char *obuf;
        if (memstream_finalize(&m, &obuf, _isz) < 0)
                return NULL;

        free_and_replace(*ibuf, obuf);

        if (highlight) {
                highlight[0] += shift[0];
                highlight[1] += shift[1];
        }

        return *ibuf;
}

char* strextend_with_separator_internal(char **x, const char *separator, ...) {
        _cleanup_free_ char *buffer = NULL;
        size_t f, l, l_separator;
        bool need_separator;
        char *nr, *p;
        va_list ap;

        if (!x)
                x = &buffer;

        l = f = strlen_ptr(*x);

        need_separator = !isempty(*x);
        l_separator = strlen_ptr(separator);

        va_start(ap, separator);
        for (const char *t;;) {
                size_t n;

                t = va_arg(ap, const char *);
                if (!t)
                        break;
                if (t == POINTER_MAX)
                        continue;

                n = strlen(t);

                if (need_separator)
                        n += l_separator;

                if (n >= SIZE_MAX - l) {
                        va_end(ap);
                        return NULL;
                }

                l += n;
                need_separator = true;
        }
        va_end(ap);

        need_separator = !isempty(*x);

        nr = realloc(*x, GREEDY_ALLOC_ROUND_UP(l+1));
        if (!nr)
                return NULL;

        *x = nr;
        p = nr + f;

        va_start(ap, separator);
        for (;;) {
                const char *t;

                t = va_arg(ap, const char *);
                if (!t)
                        break;
                if (t == POINTER_MAX)
                        continue;

                if (need_separator && separator)
                        p = stpcpy(p, separator);

                p = stpcpy(p, t);

                need_separator = true;
        }
        va_end(ap);

        assert(p == nr + l);
        *p = 0;

        /* If no buffer to extend was passed in return the start of the buffer */
        if (buffer)
                return TAKE_PTR(buffer);

        /* Otherwise we extended the buffer: return the end */
        return p;
}

int strextendf_with_separator(char **x, const char *separator, const char *format, ...) {
        size_t m, a, l_separator;
        va_list ap;
        int l;

        /* Appends a formatted string to the specified string. Don't use this in inner loops, since then
         * we'll spend a tonload of time in determining the length of the string passed in, over and over
         * again. */

        assert(x);
        assert(format);

        l_separator = isempty(*x) ? 0 : strlen_ptr(separator);

        /* Let's try to use the allocated buffer, if there's room at the end still. Otherwise let's extend by 64 chars. */
        if (*x) {
                m = strlen(*x);
                a = MALLOC_SIZEOF_SAFE(*x);
                assert(a >= m + 1);
        } else
                m = a = 0;

        if (a - m < 17 + l_separator) { /* if there's less than 16 chars space, then enlarge the buffer first */
                char *n;

                if (_unlikely_(l_separator > SIZE_MAX - 64)) /* overflow check #1 */
                        return -ENOMEM;
                if (_unlikely_(m > SIZE_MAX - 64 - l_separator)) /* overflow check #2 */
                        return -ENOMEM;

                n = realloc(*x, m + 64 + l_separator);
                if (!n)
                        return -ENOMEM;

                *x = n;
                a = MALLOC_SIZEOF_SAFE(*x);
        }

        /* Now, let's try to format the string into it */
        memcpy_safe(*x + m, separator, l_separator);
        va_start(ap, format);
        l = vsnprintf(*x + m + l_separator, a - m - l_separator, format, ap);
        va_end(ap);

        assert(l >= 0);

        if ((size_t) l < a - m - l_separator) {
                char *n;

                /* Nice! This worked. We are done. But first, let's return the extra space we don't
                 * need. This should be a cheap operation, since we only lower the allocation size here,
                 * never increase. */
                n = realloc(*x, m + (size_t) l + l_separator + 1);
                if (n)
                        *x = n;
        } else {
                char *n;

                /* Wasn't enough. Then let's allocate exactly what we need. */

                if (_unlikely_((size_t) l > SIZE_MAX - (l_separator + 1))) /* overflow check #1 */
                        goto oom;
                if (_unlikely_(m > SIZE_MAX - ((size_t) l + l_separator + 1))) /* overflow check #2 */
                        goto oom;

                a = m + (size_t) l + l_separator + 1;
                n = realloc(*x, a);
                if (!n)
                        goto oom;
                *x = n;

                va_start(ap, format);
                l = vsnprintf(*x + m + l_separator, a - m - l_separator, format, ap);
                va_end(ap);

                assert((size_t) l < a - m - l_separator);
        }

        return 0;

oom:
        /* truncate the bytes added after memcpy_safe() again */
        (*x)[m] = 0;
        return -ENOMEM;
}

char* strrep(const char *s, unsigned n) {
        char *r, *p;
        size_t l;

        assert(s);

        l = strlen(s);
        p = r = malloc(l * n + 1);
        if (!r)
                return NULL;

        for (unsigned i = 0; i < n; i++)
                p = stpcpy(p, s);

        *p = 0;
        return r;
}

int split_pair(const char *s, const char *sep, char **ret_first, char **ret_second) {
        assert(s);
        assert(!isempty(sep));
        assert(ret_first);
        assert(ret_second);

        const char *x = strstr(s, sep);
        if (!x)
                return -EINVAL;

        _cleanup_free_ char *a = strndup(s, x - s);
        if (!a)
                return -ENOMEM;

        _cleanup_free_ char *b = strdup(x + strlen(sep));
        if (!b)
                return -ENOMEM;

        *ret_first = TAKE_PTR(a);
        *ret_second = TAKE_PTR(b);
        return 0;
}

int free_and_strdup(char **p, const char *s) {
        char *t;

        assert(p);

        /* Replaces a string pointer with a strdup()ed new string,
         * possibly freeing the old one. */

        if (streq_ptr(*p, s))
                return 0;

        if (s) {
                t = strdup(s);
                if (!t)
                        return -ENOMEM;
        } else
                t = NULL;

        free_and_replace(*p, t);

        return 1;
}

int free_and_strdup_warn(char **p, const char *s) {
        int r;

        r = free_and_strdup(p, s);
        if (r < 0)
                return log_oom();
        return r;
}

int free_and_strndup(char **p, const char *s, size_t l) {
        char *t;

        assert(p);
        assert(s || l == 0);

        /* Replaces a string pointer with a strndup()ed new string,
         * freeing the old one. */

        if (!*p && !s)
                return 0;

        if (*p && s && strneq(*p, s, l) && (l > strlen(*p) || (*p)[l] == '\0'))
                return 0;

        if (s) {
                t = strndup(s, l);
                if (!t)
                        return -ENOMEM;
        } else
                t = NULL;

        free_and_replace(*p, t);
        return 1;
}

int strdup_to_full(char **ret, const char *src) {
        if (!src) {
                if (ret)
                        *ret = NULL;

                return 0;
        } else {
                if (ret) {
                        char *t = strdup(src);
                        if (!t)
                                return -ENOMEM;
                        *ret = t;
                }

                return 1;
        }
};

bool string_is_safe(const char *p) {
        if (!p)
                return false;

        /* Checks if the specified string contains no quotes or control characters */

        for (const char *t = p; *t; t++) {
                if (*t > 0 && *t < ' ') /* no control characters */
                        return false;

                if (strchr(QUOTES "\\\x7f", *t))
                        return false;
        }

        return true;
}

bool string_is_safe_ascii(const char *p) {
        return ascii_is_valid(p) && string_is_safe(p);
}

char* str_realloc(char *p) {
        /* Reallocate *p to actual size. Ignore failure, and return the original string on error. */

        if (!p)
                return NULL;

        return realloc(p, strlen(p) + 1) ?: p;
}

char* string_erase(char *x) {
        if (!x)
                return NULL;

        /* A delicious drop of snake-oil! To be called on memory where we stored passphrases or so, after we
         * used them. */
        explicit_bzero_safe(x, strlen(x));
        return x;
}

int string_truncate_lines(const char *s, size_t n_lines, char **ret) {
        const char *p = s, *e = s;
        bool truncation_applied = false;
        char *copy;
        size_t n = 0;

        assert(s);

        /* Truncate after the specified number of lines. Returns > 0 if a truncation was applied or == 0 if
         * there were fewer lines in the string anyway. Trailing newlines on input are ignored, and not
         * generated either. */

        for (;;) {
                size_t k;

                k = strcspn(p, "\n");

                if (p[k] == 0) {
                        if (k == 0) /* final empty line */
                                break;

                        if (n >= n_lines) /* above threshold */
                                break;

                        e = p + k; /* last line to include */
                        break;
                }

                assert(p[k] == '\n');

                if (n >= n_lines)
                        break;

                if (k > 0)
                        e = p + k;

                p += k + 1;
                n++;
        }

        /* e points after the last character we want to keep */
        if (isempty(e))
                copy = strdup(s);
        else {
                if (!in_charset(e, "\n")) /* We only consider things truncated if we remove something that
                                           * isn't a new-line or a series of them */
                        truncation_applied = true;

                copy = strndup(s, e - s);
        }
        if (!copy)
                return -ENOMEM;

        *ret = copy;
        return truncation_applied;
}

int string_extract_line(const char *s, size_t i, char **ret) {
        const char *p = s;
        size_t c = 0;

        /* Extract the i'nth line from the specified string. Returns > 0 if there are more lines after that,
         * and == 0 if we are looking at the last line or already beyond the last line. As special
         * optimization, if the first line is requested and the string only consists of one line we return
         * NULL, indicating the input string should be used as is, and avoid a memory allocation for a very
         * common case. */

        for (;;) {
                const char *q;

                q = strchr(p, '\n');
                if (i == c) {
                        /* The line we are looking for! */

                        if (q) {
                                char *m;

                                m = strndup(p, q - p);
                                if (!m)
                                        return -ENOMEM;

                                *ret = m;
                                return !isempty(q + 1); /* More coming? */
                        } else
                                /* Tell the caller to use the input string if equal */
                                return strdup_to(ret, p != s ? p : NULL);
                }

                if (!q)
                        /* No more lines, return empty line */
                        return strdup_to(ret, "");

                p = q + 1;
                c++;
        }
}

int string_contains_word_strv(const char *string, const char *separators, char * const *words, const char **ret_word) {
        /* In the default mode with no separators specified, we split on whitespace and coalesce separators. */
        const ExtractFlags flags = separators ? EXTRACT_DONT_COALESCE_SEPARATORS : 0;
        const char *found = NULL;
        int r;

        for (;;) {
                _cleanup_free_ char *w = NULL;

                r = extract_first_word(&string, &w, separators, flags);
                if (r < 0)
                        return r;
                if (r == 0)
                        break;

                found = strv_find(words, w);
                if (found)
                        break;
        }

        if (ret_word)
                *ret_word = found;
        return !!found;
}

bool streq_skip_trailing_chars(const char *s1, const char *s2, const char *ok) {
        if (!s1 && !s2)
                return true;
        if (!s1 || !s2)
                return false;

        if (!ok)
                ok = WHITESPACE;

        for (; *s1 && *s2; s1++, s2++)
                if (*s1 != *s2)
                        break;

        return in_charset(s1, ok) && in_charset(s2, ok);
}

char* string_replace_char(char *str, char old_char, char new_char) {
        assert(str);
        assert(old_char != '\0');
        assert(new_char != '\0');
        assert(old_char != new_char);

        for (char *p = strchr(str, old_char); p; p = strchr(p + 1, old_char))
                *p = new_char;

        return str;
}

int make_cstring(const char *s, size_t n, MakeCStringMode mode, char **ret) {
        char *b;

        assert(s || n == 0);
        assert(mode >= 0);
        assert(mode < _MAKE_CSTRING_MODE_MAX);

        /* Converts a sized character buffer into a NUL-terminated NUL string, refusing if there are embedded
         * NUL bytes. Whether to expect a trailing NUL byte can be specified via 'mode' */

        if (n == 0) {
                if (mode == MAKE_CSTRING_REQUIRE_TRAILING_NUL)
                        return -EINVAL;

                if (!ret)
                        return 0;

                b = new0(char, 1);
        } else {
                const char *nul;

                nul = memchr(s, 0, n);
                if (nul) {
                        if (nul < s + n - 1 || /* embedded NUL? */
                            mode == MAKE_CSTRING_REFUSE_TRAILING_NUL)
                                return -EINVAL;

                        n--;
                } else if (mode == MAKE_CSTRING_REQUIRE_TRAILING_NUL)
                        return -EINVAL;

                if (!ret)
                        return 0;

                b = memdup_suffix0(s, n);
        }
        if (!b)
                return -ENOMEM;

        *ret = b;
        return 0;
}

size_t strspn_from_end(const char *str, const char *accept) {
        size_t n = 0;

        if (isempty(str))
                return 0;

        if (isempty(accept))
                return 0;

        for (const char *p = str + strlen(str); p > str && strchr(accept, p[-1]); p--)
                n++;

        return n;
}

char* strdupspn(const char *a, const char *accept) {
        if (isempty(a) || isempty(accept))
                return strdup("");

        return strndup(a, strspn(a, accept));
}

char* strdupcspn(const char *a, const char *reject) {
        if (isempty(a))
                return strdup("");
        if (isempty(reject))
                return strdup(a);

        return strndup(a, strcspn(a, reject));
}

char* find_line_startswith(const char *haystack, const char *needle) {
        char *p;

        assert(haystack);
        assert(needle);

        /* Finds the first line in 'haystack' that starts with the specified string. Returns a pointer to the
         * first character after it */

        p = strstr(haystack, needle);
        if (!p)
                return NULL;

        if (p > haystack)
                while (p[-1] != '\n') {
                        p = strstr(p + 1, needle);
                        if (!p)
                                return NULL;
                }

        return p + strlen(needle);
}

char* find_line(const char *haystack, const char *needle) {
        char *p;

        assert(haystack);
        assert(needle);

        /* Finds the first line in 'haystack' that match the specified string. Returns a pointer to the
         * beginning of the line */

        p = find_line_startswith(haystack, needle);
        if (!p)
                return NULL;

        if (*p == 0 || strchr(NEWLINE, *p))
                return p - strlen(needle);

        return NULL;
}

char* find_line_after(const char *haystack, const char *needle) {
        char *p;

        assert(haystack);
        assert(needle);

        /* Finds the first line in 'haystack' that match the specified string. Returns a pointer to the
         * next line after it */

        p = find_line_startswith(haystack, needle);
        if (!p)
                return NULL;

        if (*p == 0)
                return p;
        if (strchr(NEWLINE, *p))
                return p + 1;

        return NULL;
}

bool version_is_valid(const char *s) {
        if (isempty(s))
                return false;

        if (!filename_part_is_valid(s))
                return false;

        /* This is a superset of the characters used by semver. We additionally allow "," and "_". */
        if (!in_charset(s, ALPHANUMERICAL ".,_-+"))
                return false;

        return true;
}

bool version_is_valid_versionspec(const char *s) {
        if (!filename_part_is_valid(s))
                return false;

        if (!in_charset(s, ALPHANUMERICAL "-.~^"))
                return false;

        return true;
}

ssize_t strlevenshtein(const char *x, const char *y) {
        _cleanup_free_ size_t *t0 = NULL, *t1 = NULL, *t2 = NULL;
        size_t xl, yl;

        /* This is inspired from the Linux kernel's Levenshtein implementation */

        if (streq_ptr(x, y))
                return 0;

        xl = strlen_ptr(x);
        if (xl > SSIZE_MAX)
                return -E2BIG;

        yl = strlen_ptr(y);
        if (yl > SSIZE_MAX)
                return -E2BIG;

        if (isempty(x))
                return yl;
        if (isempty(y))
                return xl;

        t0 = new0(size_t, yl + 1);
        if (!t0)
                return -ENOMEM;
        t1 = new0(size_t, yl + 1);
        if (!t1)
                return -ENOMEM;
        t2 = new0(size_t, yl + 1);
        if (!t2)
                return -ENOMEM;

        for (size_t i = 0; i <= yl; i++)
                t1[i] = i;

        for (size_t i = 0; i < xl; i++) {
                t2[0] = i + 1;

                for (size_t j = 0; j < yl; j++) {
                        /* Substitution */
                        t2[j+1] = t1[j] + (x[i] != y[j]);

                        /* Swap */
                        if (i > 0 && j > 0 && x[i-1] == y[j] && x[i] == y[j-1] && t2[j+1] > t0[j-1] + 1)
                                t2[j+1] = t0[j-1] + 1;

                        /* Deletion */
                        if (t2[j+1] > t1[j+1] + 1)
                                t2[j+1] = t1[j+1] + 1;

                        /* Insertion */
                        if (t2[j+1] > t2[j] + 1)
                                t2[j+1] = t2[j] + 1;
                }

                size_t *dummy = t0;
                t0 = t1;
                t1 = t2;
                t2 = dummy;
        }

        return t1[yl];
}

char* strrstr(const char *haystack, const char *needle) {
        /* Like strstr() but returns the last rather than the first occurrence of "needle" in "haystack". */

        if (!haystack || !needle)
                return NULL;

        /* Special case: for the empty string we return the very last possible occurrence, i.e. *after* the
         * last char, not before. */
        if (*needle == 0)
                return strchr(haystack, 0);

        for (const char *p = strstr(haystack, needle), *q; p; p = q) {
                q = strstr(p + 1, needle);
                if (!q)
                        return (char *) p;
        }
        return NULL;
}

size_t str_common_prefix(const char *a, const char *b) {
        assert(a);
        assert(b);

        /* Returns the length of the common prefix of the two specified strings, or SIZE_MAX in case the
         * strings are fully identical. */

        for (size_t n = 0;; n++) {
                char c = a[n];
                if (c != b[n])
                        return n;
                if (c == 0)
                        return SIZE_MAX;
        }
}

systemd / systemd / 15150396955

Source File Press 'n' to go to next uncovered line, 'b' for previous

Source File
Press 'n' to go to next uncovered line, 'b' for previous