libmount: add mnt_optstr_* functions

This set of functions allows to set/get/remove/append option in
unparsed options string.

Signed-off-by: Karel Zak <kzak@redhat.com>

1 files changed, 416 insertions, 0 deletions

diff --git a/shlibs/mount/src/optstr.c b/shlibs/mount/src/optstr.c
new file mode 100644
index 000000000..3e4eb482d
--- /dev/null
+++ b/shlibs/mount/src/optstr.c
@@ -0,0 +1,416 @@
+/*
+ * Copyright (C) 2008-2009 Karel Zak <kzak@redhat.com>
+ *
+ * This file may be redistributed under the terms of the
+ * GNU Lesser General Public License.
+ */
+
+#include <string.h>
+#include <stdlib.h>
+#include <ctype.h>
+#include <errno.h>
+
+#include "nls.h"
+#include "mountP.h"
+
+/*
+ * Parses the first option from @optstr. The @optstr pointer is set to begin of
+ * the next option.
+ *
+ * Returns -1 on parse error, 1 at the end of optstr and 0 on success.
+ */
+static int mnt_optstr_parse_next(char **optstr,	 char **name, size_t *namesz,
+					char **value, size_t *valsz)
+{
+	int open_quote = 0;
+	char *start = NULL, *stop = NULL, *p, *sep = NULL;
+	char *optstr0;
+
+	assert(optstr);
+	assert(*optstr);
+
+	optstr0 = *optstr;
+
+	if (name)
+		*name = NULL;
+	if (namesz)
+		*namesz = 0;
+	if (value)
+		*value = NULL;
+	if (valsz)
+		*valsz = 0;
+
+	for (p = optstr0; p && *p; p++) {
+		if (!start)
+			start = p;		/* begin of the option item */
+		if (*p == '"')
+			open_quote ^= 1;	/* reverse the status */
+		if (open_quote)
+			continue;		/* still in quoted block */
+		if (!sep && *p == '=')
+			sep = p;		/* name and value separator */
+		if (*p == ',')
+			stop = p;		/* terminate the option item */
+		else if (*(p + 1) == '\0')
+			stop = p + 1;		/* end of optstr */
+		if (!start || !stop)
+			continue;
+		if (stop <= start)
+			goto error;
+
+		if (name)
+			*name = start;
+		if (namesz)
+			*namesz = sep ? sep - start : stop - start;
+		*optstr = *stop ? stop + 1 : stop;
+
+		if (sep) {
+			if (value)
+				*value = sep + 1;
+			if (valsz)
+				*valsz = stop - sep - 1;
+		}
+		return 0;
+	}
+
+	return 1;				/* end of optstr */
+
+error:
+	DBG(DEBUG_OPTIONS, fprintf(stderr,
+			"libmount: parse error: \"%s\"\n", optstr0));
+	return -1;
+}
+
+/*
+ * Locates the first option that match with @name. The @end is set to
+ * char behind the option (it means ',' or \0).
+ *
+ * Returns -1 on parse error, 1 when not found and 0 on success.
+ */
+static int mnt_optstr_locate_option(char *optstr, const char *name, char **begin,
+					char **end, char **value, size_t *valsz)
+{
+	char *n;
+	size_t namesz, nsz;
+	int rc;
+
+	assert(name);
+	assert(optstr);
+
+	namesz = strlen(name);
+
+	do {
+		rc = mnt_optstr_parse_next(&optstr, &n, &nsz, value, valsz);
+		if (rc)
+			break;
+
+		if (namesz == nsz && strncmp(n, name, nsz) == 0) {
+			if (begin)
+				*begin = n;
+			if (end)
+				*end = *(optstr - 1) == ',' ?
+					optstr - 1 : optstr;
+			return 0;
+		}
+	} while(1);
+
+	DBG(DEBUG_OPTIONS, fprintf(stderr,
+			"libmount: can't found '%s' option\n", name));
+	return rc;
+}
+
+/**
+ * mnt_optstr_next_option:
+ * @optstr: option string, returns position to next option
+ * @name: returns option name
+ * @namesz: returns option name length
+ * @value: returns option value or NULL
+ * @valuesz: returns option value length or zero
+ *
+ * Parses the first option in @optstr  or -1 in case of error.
+ *
+ * Returns 0 on success, 1 at the end of @optstr or -1 in case of error.
+ */
+int mnt_optstr_next_option(char **optstr, char **name, size_t *namesz,
+					char **value, size_t *valuesz)
+{
+	if (!optstr || !*optstr)
+		return -1;
+	return mnt_optstr_parse_next(optstr, name, namesz, value, valuesz);
+}
+
+/**
+ * mnt_optstr_append_option:
+ * @optstr: option string or NULL
+ * @name: value name
+ * @value: value
+ *
+ * Returns: reallocated (or newly allocated) @optstr with ,name=value
+ */
+int mnt_optstr_append_option(char **optstr, const char *name, const char *value)
+{
+	char *p;
+	size_t sz, vsz, osz, nsz;
+
+	if (!name)
+		return -1;
+
+	osz = *optstr ? strlen(*optstr) : 0;
+	nsz = strlen(name);
+	vsz = value ? strlen(value) : 0;
+
+	sz = osz + nsz + 1;		/* 1: '\0' */
+	if (osz)
+		sz++;			/* ',' options separator */
+	if (vsz)
+		sz += vsz + 1;		/* 1: '=' */
+
+	p = realloc(*optstr, sz);
+	if (!p)
+		return -1;
+	*optstr = p;
+
+	if (osz) {
+		p += osz;
+		*p++ = ',';
+	}
+
+	memcpy(p, name, nsz);
+	p += nsz;
+
+	if (vsz) {
+		*p++ = '=';
+		memcpy(p, value, vsz);
+		p += vsz;
+	}
+	*p = '\0';
+
+	return 0;
+}
+
+/**
+ * mnt_optstr_get_option:
+ * @optstr: string with comma separated list of options
+ * @name: requested option name
+ * @value: returns pointer to the begin of the value (e.g. name=VALUE) or NULL
+ * @valsz: returns size of the value or 0
+ *
+ * Returns: 0 on success, 1 when not found the @name or -1 in case of error.
+ */
+int mnt_optstr_get_option(char *optstr, const char *name,
+				char **value, size_t *valsz)
+{
+	return mnt_optstr_locate_option(optstr, name, NULL, NULL, value, valsz);
+}
+
+/* Removes substring located between @begin and @end from @str
+ * -- result never starts or ends with comma or contains two commas
+ *    (e.g. ",aaa,bbb" or "aaa,,bbb" or "aaa,")
+ */
+static void remove_substring(char *str, char *begin, char *end)
+{
+	size_t sz = strlen(end);
+
+	if ((begin == str || *(begin - 1) == ',') && *end == ',')
+		end++;
+
+	memmove(begin, end, sz + 1);
+	if (!*begin && *(begin - 1) == ',')
+		*(begin - 1) = '\0';
+}
+
+/* insert '=substr' to @str on position @pos */
+static int insert_substring(char **str, char *pos, const char *substr)
+{
+	char *p;
+	size_t ssz = strlen(substr);	/* substring size */
+
+	p = realloc(*str, strlen(*str) + 1 + ssz);
+	if (!p)
+		return -1;
+	*str = p;
+
+	memmove(pos + ssz + 1, pos, strlen(pos) + 1);
+	*pos++ = '=';
+	memcpy(pos, substr, ssz);
+	return 0;
+}
+
+/**
+ * mnt_optstr_set_option:
+ * @optstr: string with comma separated list of options
+ * @name: requested option
+ * @value: new value or NULL
+ *
+ * Set or unset option @value.
+ *
+ * Returns: 0 on success, 1 when not found the @name or -1 in case of error.
+ */
+int mnt_optstr_set_option(char **optstr, const char *name, const char *value)
+{
+	char *val = NULL, *begin, *end, *nameend;
+	size_t valsz;
+	int rc = 1;
+
+	if (!optstr)
+		return -1;
+	if (*optstr)
+		rc = mnt_optstr_locate_option(*optstr, name,
+					&begin, &end, &val, &valsz);
+	if (rc == -1)
+		/* parse error */
+		return -1;
+	if (rc == 1)
+		/* not found */
+		return mnt_optstr_append_option(optstr, name, value);
+
+	nameend = begin + strlen(name);
+
+	if (value == NULL && val && valsz)
+		/* remove unwanted "=value" */
+		remove_substring(*optstr, nameend, end);
+
+	else if (value && val == NULL)
+		/* insert "=value" */
+		rc = insert_substring(optstr, nameend, value);
+
+	else if (value && val && strlen(value) == valsz)
+		/* simply replace =value */
+		memcpy(val, value, valsz);
+
+	else if (value && val) {
+		remove_substring(*optstr, nameend, end);
+		rc = insert_substring(optstr, nameend, value);
+	}
+
+
+	return 0;
+}
+
+/**
+ * mnt_optstr_remove_option:
+ * @optstr: string with comma separated list of options
+ * @name: requested option name
+ *
+ * Returns: 0 on success, 1 when not found the @name or -1 in case of error.
+ */
+int mnt_optstr_remove_option(char **optstr, const char *name)
+{
+	char *begin, *end;
+	int rc;
+
+	rc = mnt_optstr_locate_option(*optstr, name,
+				&begin, &end, NULL, NULL);
+	if (rc != 0)
+		return rc;
+
+	remove_substring(*optstr, begin, end);
+	return 0;
+}
+
+#ifdef TEST_PROGRAM
+
+int test_append(struct mtest *ts, int argc, char *argv[])
+{
+	const char *value = NULL, *name;
+	char *optstr;
+
+	if (argc < 3)
+		goto done;
+	optstr = strdup(argv[1]);
+	name = argv[2];
+
+	if (argc == 4)
+		value = argv[3];
+
+	if (mnt_optstr_append_option(&optstr, name, value) == 0) {
+		printf("result: >%s<\n", optstr);
+		return 0;
+	}
+done:
+	return -1;
+}
+
+int test_set(struct mtest *ts, int argc, char *argv[])
+{
+	const char *value = NULL, *name;
+	char *optstr;
+
+	if (argc < 3)
+		goto done;
+	optstr = strdup(argv[1]);
+	name = argv[2];
+
+	if (argc == 4)
+		value = argv[3];
+
+	if (mnt_optstr_set_option(&optstr, name, value) == 0) {
+		printf("result: >%s<\n", optstr);
+		return 0;
+	}
+done:
+	return -1;
+}
+
+int test_get(struct mtest *ts, int argc, char *argv[])
+{
+	char *optstr;
+	const char *name;
+	char *val = NULL;
+	size_t sz = 0;
+	int rc;
+
+	if (argc < 2)
+		goto done;
+	optstr = argv[1];
+	name = argv[2];
+
+	rc = mnt_optstr_get_option(optstr, name, &val, &sz);
+	if (rc == 0) {
+		printf("found; name: %s", name);
+		if (sz) {
+			printf(", argument: size=%zd data=", sz);
+			if (fwrite(val, 1, sz, stdout) != sz)
+				goto done;
+		}
+		printf("\n");
+		return 0;
+	} else if (rc == 1)
+		printf("%s: not found\n", name);
+	else
+		printf("parse error: %s\n", optstr);
+done:
+	return -1;
+}
+
+int test_remove(struct mtest *ts, int argc, char *argv[])
+{
+	const char *name;
+	char *optstr;
+
+	if (argc < 3)
+		goto done;
+	optstr = strdup(argv[1]);
+	name = argv[2];
+
+	if (mnt_optstr_remove_option(&optstr, name) == 0) {
+		printf("result: >%s<\n", optstr);
+		return 0;
+	}
+done:
+	return -1;
+}
+
+
+int main(int argc, char *argv[])
+{
+	struct mtest tss[] = {
+		{ "--append", test_append, "<optstr> <name> [<value>]  append value to optstr" },
+		{ "--set",    test_set,    "<optstr> <name> [<value>]  (un)set value" },
+		{ "--get",    test_get,    "<optstr> <name>            search name in optstr" },
+		{ "--remove", test_remove, "<optstr> <name>            remove name in optstr" },
+		{ NULL }
+	};
+	return  mnt_run_test(tss, argc, argv);
+}
+#endif /* TEST_PROGRAM */