util: split out extract_first_word() and related calls into extract-word.[ch]

This is quite a lot of code these days, hence move it to its own source
file.

1 files changed, 274 insertions, 0 deletions

diff --git a/src/basic/extract-word.c b/src/basic/extract-word.c
new file mode 100644
index 0000000000..474e6fdd57
--- /dev/null
+++ b/src/basic/extract-word.c
@@ -0,0 +1,274 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+/***
+  This file is part of systemd.
+
+  Copyright 2010 Lennart Poettering
+
+  systemd is free software; you can redistribute it and/or modify it
+  under the terms of the GNU Lesser General Public License as published by
+  the Free Software Foundation; either version 2.1 of the License, or
+  (at your option) any later version.
+
+  systemd is distributed in the hope that it will be useful, but
+  WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+  Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public License
+  along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include "utf8.h"
+#include "util.h"
+
+#include "extract-word.h"
+
+int extract_first_word(const char **p, char **ret, const char *separators, ExtractFlags flags) {
+        _cleanup_free_ char *s = NULL;
+        size_t allocated = 0, sz = 0;
+        int r;
+
+        char quote = 0;                 /* 0 or ' or " */
+        bool backslash = false;         /* whether we've just seen a backslash */
+        bool separator = false;         /* whether we've just seen a separator */
+        bool start = true;              /* false means we're looking at a value */
+
+        assert(p);
+        assert(ret);
+
+        if (!separators)
+                separators = WHITESPACE;
+
+        /* Bail early if called after last value or with no input */
+        if (!*p)
+                goto finish_force_terminate;
+
+        /* Parses the first word of a string, and returns it in
+         * *ret. Removes all quotes in the process. When parsing fails
+         * (because of an uneven number of quotes or similar), leaves
+         * the pointer *p at the first invalid character. */
+
+        for (;;) {
+                char c = **p;
+
+                if (start) {
+                        if (flags & EXTRACT_DONT_COALESCE_SEPARATORS)
+                                if (!GREEDY_REALLOC(s, allocated, sz+1))
+                                        return -ENOMEM;
+
+                        if (c == 0)
+                                goto finish_force_terminate;
+                        else if (strchr(separators, c)) {
+                                (*p) ++;
+                                if (flags & EXTRACT_DONT_COALESCE_SEPARATORS)
+                                        goto finish_force_next;
+                                continue;
+                        }
+
+                        /* We found a non-blank character, so we will always
+                         * want to return a string (even if it is empty),
+                         * allocate it here. */
+                        if (!GREEDY_REALLOC(s, allocated, sz+1))
+                                return -ENOMEM;
+
+                        start = false;
+                }
+
+                if (backslash) {
+                        if (!GREEDY_REALLOC(s, allocated, sz+7))
+                                return -ENOMEM;
+
+                        if (c == 0) {
+                                if ((flags & EXTRACT_CUNESCAPE_RELAX) &&
+                                    (!quote || flags & EXTRACT_RELAX)) {
+                                        /* If we find an unquoted trailing backslash and we're in
+                                         * EXTRACT_CUNESCAPE_RELAX mode, keep it verbatim in the
+                                         * output.
+                                         *
+                                         * Unbalanced quotes will only be allowed in EXTRACT_RELAX
+                                         * mode, EXTRACT_CUNESCAPE_RELAX mode does not allow them.
+                                         */
+                                        s[sz++] = '\\';
+                                        goto finish_force_terminate;
+                                }
+                                if (flags & EXTRACT_RELAX)
+                                        goto finish_force_terminate;
+                                return -EINVAL;
+                        }
+
+                        if (flags & EXTRACT_CUNESCAPE) {
+                                uint32_t u;
+
+                                r = cunescape_one(*p, (size_t) -1, &c, &u);
+                                if (r < 0) {
+                                        if (flags & EXTRACT_CUNESCAPE_RELAX) {
+                                                s[sz++] = '\\';
+                                                s[sz++] = c;
+                                                goto end_escape;
+                                        }
+                                        return -EINVAL;
+                                }
+
+                                (*p) += r - 1;
+
+                                if (c != 0)
+                                        s[sz++] = c; /* normal explicit char */
+                                else
+                                        sz += utf8_encode_unichar(s + sz, u); /* unicode chars we'll encode as utf8 */
+                        } else
+                                s[sz++] = c;
+
+end_escape:
+                        backslash = false;
+
+                } else if (quote) {     /* inside either single or double quotes */
+                        if (c == 0) {
+                                if (flags & EXTRACT_RELAX)
+                                        goto finish_force_terminate;
+                                return -EINVAL;
+                        } else if (c == quote)          /* found the end quote */
+                                quote = 0;
+                        else if (c == '\\')
+                                backslash = true;
+                        else {
+                                if (!GREEDY_REALLOC(s, allocated, sz+2))
+                                        return -ENOMEM;
+
+                                s[sz++] = c;
+                        }
+
+                } else if (separator) {
+                        if (c == 0)
+                                goto finish_force_terminate;
+                        if (!strchr(separators, c))
+                                goto finish;
+
+                } else {
+                        if (c == 0)
+                                goto finish_force_terminate;
+                        else if ((c == '\'' || c == '"') && (flags & EXTRACT_QUOTES))
+                                quote = c;
+                        else if (c == '\\')
+                                backslash = true;
+                        else if (strchr(separators, c)) {
+                                if (flags & EXTRACT_DONT_COALESCE_SEPARATORS) {
+                                        (*p) ++;
+                                        goto finish_force_next;
+                                }
+                                separator = true;
+                        } else {
+                                if (!GREEDY_REALLOC(s, allocated, sz+2))
+                                        return -ENOMEM;
+
+                                s[sz++] = c;
+                        }
+                }
+
+                (*p) ++;
+        }
+
+finish_force_terminate:
+        *p = NULL;
+finish:
+        if (!s) {
+                *p = NULL;
+                *ret = NULL;
+                return 0;
+        }
+
+finish_force_next:
+        s[sz] = 0;
+        *ret = s;
+        s = NULL;
+
+        return 1;
+}
+
+int extract_first_word_and_warn(
+                const char **p,
+                char **ret,
+                const char *separators,
+                ExtractFlags flags,
+                const char *unit,
+                const char *filename,
+                unsigned line,
+                const char *rvalue) {
+
+        /* Try to unquote it, if it fails, warn about it and try again but this
+         * time using EXTRACT_CUNESCAPE_RELAX to keep the backslashes verbatim
+         * in invalid escape sequences. */
+        const char *save;
+        int r;
+
+        save = *p;
+        r = extract_first_word(p, ret, separators, flags);
+        if (r < 0 && !(flags & EXTRACT_CUNESCAPE_RELAX)) {
+
+                /* Retry it with EXTRACT_CUNESCAPE_RELAX. */
+                *p = save;
+                r = extract_first_word(p, ret, separators, flags|EXTRACT_CUNESCAPE_RELAX);
+                if (r < 0)
+                        log_syntax(unit, LOG_ERR, filename, line, r, "Unbalanced quoting in command line, ignoring: \"%s\"", rvalue);
+                else
+                        log_syntax(unit, LOG_WARNING, filename, line, 0, "Invalid escape sequences in command line: \"%s\"", rvalue);
+        }
+
+        return r;
+}
+
+int extract_many_words(const char **p, const char *separators, ExtractFlags flags, ...) {
+        va_list ap;
+        char **l;
+        int n = 0, i, c, r;
+
+        /* Parses a number of words from a string, stripping any
+         * quotes if necessary. */
+
+        assert(p);
+
+        /* Count how many words are expected */
+        va_start(ap, flags);
+        for (;;) {
+                if (!va_arg(ap, char **))
+                        break;
+                n++;
+        }
+        va_end(ap);
+
+        if (n <= 0)
+                return 0;
+
+        /* Read all words into a temporary array */
+        l = newa0(char*, n);
+        for (c = 0; c < n; c++) {
+
+                r = extract_first_word(p, &l[c], separators, flags);
+                if (r < 0) {
+                        int j;
+
+                        for (j = 0; j < c; j++)
+                                free(l[j]);
+
+                        return r;
+                }
+
+                if (r == 0)
+                        break;
+        }
+
+        /* If we managed to parse all words, return them in the passed
+         * in parameters */
+        va_start(ap, flags);
+        for (i = 0; i < n; i++) {
+                char **v;
+
+                v = va_arg(ap, char **);
+                assert(v);
+
+                *v = l[i];
+        }
+        va_end(ap);
+
+        return c;
+}