Create qemu-option.h

This patch creates a new header file and the corresponding implementation file
for parsing of parameter strings for options (like used in -drive). Part of
this is code moved from vl.c (so qemu-img can use it later).

The idea is to have a data structure describing all accepted parameters. When
parsing a parameter string, the structure is copied and filled with the
parameter values.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

1 files changed, 349 insertions, 0 deletions

diff --git a/qemu-option.c b/qemu-option.c
new file mode 100644
index 000000000..3cebdd51e
--- /dev/null
+++ b/qemu-option.c
@@ -0,0 +1,349 @@
+/*
+ * Commandline option parsing functions
+ *
+ * Copyright (c) 2003-2008 Fabrice Bellard
+ * Copyright (c) 2009 Kevin Wolf <kwolf@redhat.com>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include <stdio.h>
+#include <string.h>
+
+#include "qemu-common.h"
+#include "qemu-option.h"
+
+/*
+ * Extracts the name of an option from the parameter string (p points at the
+ * first byte of the option name)
+ *
+ * The option name is delimited by delim (usually , or =) or the string end
+ * and is copied into buf. If the option name is longer than buf_size, it is
+ * truncated. buf is always zero terminated.
+ *
+ * The return value is the position of the delimiter/zero byte after the option
+ * name in p.
+ */
+const char *get_opt_name(char *buf, int buf_size, const char *p, char delim)
+{
+    char *q;
+
+    q = buf;
+    while (*p != '\0' && *p != delim) {
+        if (q && (q - buf) < buf_size - 1)
+            *q++ = *p;
+        p++;
+    }
+    if (q)
+        *q = '\0';
+
+    return p;
+}
+
+/*
+ * Extracts the value of an option from the parameter string p (p points at the
+ * first byte of the option value)
+ *
+ * This function is comparable to get_opt_name with the difference that the
+ * delimiter is fixed to be comma which starts a new option. To specify an
+ * option value that contains commas, double each comma.
+ */
+const char *get_opt_value(char *buf, int buf_size, const char *p)
+{
+    char *q;
+
+    q = buf;
+    while (*p != '\0') {
+        if (*p == ',') {
+            if (*(p + 1) != ',')
+                break;
+            p++;
+        }
+        if (q && (q - buf) < buf_size - 1)
+            *q++ = *p;
+        p++;
+    }
+    if (q)
+        *q = '\0';
+
+    return p;
+}
+
+/*
+ * Searches an option list for an option with the given name
+ */
+QEMUOptionParameter *get_option_parameter(QEMUOptionParameter *list,
+    const char *name)
+{
+    while (list && list->name) {
+        if (!strcmp(list->name, name)) {
+            return list;
+        }
+        list++;
+    }
+
+    return NULL;
+}
+
+/*
+ * Sets the value of a parameter in a given option list. The parsing of the
+ * value depends on the type of option:
+ *
+ * OPT_FLAG (uses value.n):
+ *      If no value is given, the flag is set to 1.
+ *      Otherwise the value must be "on" (set to 1) or "off" (set to 0)
+ *
+ * OPT_STRING (uses value.s):
+ *      value is strdup()ed and assigned as option value
+ *
+ * OPT_SIZE (uses value.n):
+ *      The value is converted to an integer. Suffixes for kilobytes etc. are
+ *      allowed (powers of 1024).
+ *
+ * Returns 0 on succes, -1 in error cases
+ */
+int set_option_parameter(QEMUOptionParameter *list, const char *name,
+    const char *value)
+{
+    // Find a matching parameter
+    list = get_option_parameter(list, name);
+    if (list == NULL) {
+        fprintf(stderr, "Unknown option '%s'\n", name);
+        return -1;
+    }
+
+    // Process parameter
+    switch (list->type) {
+    case OPT_FLAG:
+        if (value != NULL) {
+            if (!strcmp(value, "on")) {
+                list->value.n = 1;
+            } else if (!strcmp(value, "off")) {
+                list->value.n = 0;
+            } else {
+                fprintf(stderr, "Option '%s': Use 'on' or 'off'\n", name);
+                return -1;
+            }
+        } else {
+            list->value.n = 1;
+        }
+        break;
+
+    case OPT_STRING:
+        if (value != NULL) {
+            list->value.s = strdup(value);
+        } else {
+            fprintf(stderr, "Option '%s' needs a parameter\n", name);
+            return -1;
+        }
+        break;
+
+    case OPT_SIZE:
+        if (value != NULL) {
+            double sizef = strtod(value, (char**) &value);
+
+            switch (*value) {
+            case 'T':
+                sizef *= 1024;
+            case 'G':
+                sizef *= 1024;
+            case 'M':
+                sizef *= 1024;
+            case 'K':
+            case 'k':
+                sizef *= 1024;
+            case 'b':
+            case '\0':
+                list->value.n = (uint64_t) sizef;
+                break;
+            default:
+                fprintf(stderr, "Option '%s' needs size as parameter\n", name);
+                fprintf(stderr, "You may use k, M, G or T suffixes for "
+                    "kilobytes, megabytes, gigabytes and terabytes.\n");
+                return -1;
+            }
+        } else {
+            fprintf(stderr, "Option '%s' needs a parameter\n", name);
+            return -1;
+        }
+        break;
+    default:
+        fprintf(stderr, "Bug: Option '%s' has an unknown type\n", name);
+        return -1;
+    }
+
+    return 0;
+}
+
+/*
+ * Sets the given parameter to an integer instead of a string.
+ * This function cannot be used to set string options.
+ *
+ * Returns 0 on success, -1 in error cases
+ */
+int set_option_parameter_int(QEMUOptionParameter *list, const char *name,
+    uint64_t value)
+{
+    // Find a matching parameter
+    list = get_option_parameter(list, name);
+    if (list == NULL) {
+        fprintf(stderr, "Unknown option '%s'\n", name);
+        return -1;
+    }
+
+    // Process parameter
+    switch (list->type) {
+    case OPT_FLAG:
+    case OPT_NUMBER:
+    case OPT_SIZE:
+        list->value.n = value;
+        break;
+
+    default:
+        return -1;
+    }
+
+    return 0;
+}
+
+/*
+ * Frees a option list. If it contains strings, the strings are freed as well.
+ */
+void free_option_parameters(QEMUOptionParameter *list)
+{
+    QEMUOptionParameter *cur = list;
+
+    while (cur && cur->name) {
+        if (cur->type == OPT_STRING) {
+            free(cur->value.s);
+        }
+        cur++;
+    }
+
+    free(list);
+}
+
+/*
+ * Parses a parameter string (param) into an option list (dest).
+ *
+ * list is the templace is. If dest is NULL, a new copy of list is created for
+ * it. If list is NULL, this function fails.
+ *
+ * A parameter string consists of one or more parameters, separated by commas.
+ * Each parameter consists of its name and possibly of a value. In the latter
+ * case, the value is delimited by an = character. To specify a value which
+ * contains commas, double each comma so it won't be recognized as the end of
+ * the parameter.
+ *
+ * For more details of the parsing see above.
+ *
+ * Returns a pointer to the first element of dest (or the newly allocated copy)
+ * or NULL in error cases
+ */
+QEMUOptionParameter *parse_option_parameters(const char *param,
+    QEMUOptionParameter *list, QEMUOptionParameter *dest)
+{
+    QEMUOptionParameter *cur;
+    QEMUOptionParameter *allocated = NULL;
+    char name[256];
+    char value[256];
+    char *param_delim, *value_delim;
+    char next_delim;
+    size_t num_options;
+
+    if (list == NULL) {
+        return NULL;
+    }
+
+    if (dest == NULL) {
+        // Count valid options
+        num_options = 0;
+        cur = list;
+        while (cur->name) {
+            num_options++;
+            cur++;
+        }
+
+        // Create a copy of the option list to fill in values
+        dest = qemu_mallocz((num_options + 1) * sizeof(QEMUOptionParameter));
+        allocated = dest;
+        memcpy(dest, list, (num_options + 1) * sizeof(QEMUOptionParameter));
+    }
+
+    while (*param) {
+
+        // Find parameter name and value in the string
+        param_delim = strchr(param, ',');
+        value_delim = strchr(param, '=');
+
+        if (value_delim && (value_delim < param_delim || !param_delim)) {
+            next_delim = '=';
+        } else {
+            next_delim = ',';
+            value_delim = NULL;
+        }
+
+        param = get_opt_name(name, sizeof(name), param, next_delim);
+        if (value_delim) {
+            param = get_opt_value(value, sizeof(value), param + 1);
+        }
+        if (*param != '\0') {
+            param++;
+        }
+
+        // Set the parameter
+        if (set_option_parameter(dest, name, value_delim ? value : NULL)) {
+            goto fail;
+        }
+    }
+
+    return dest;
+
+fail:
+    // Only free the list if it was newly allocated
+    free_option_parameters(allocated);
+    return NULL;
+}
+
+/*
+ * Prints all options of a list that have a value to stdout
+ */
+void print_option_parameters(QEMUOptionParameter *list)
+{
+    while (list && list->name) {
+        switch (list->type) {
+            case OPT_STRING:
+                 if (list->value.s != NULL) {
+                     printf("%s='%s' ", list->name, list->value.s);
+                 }
+                break;
+            case OPT_FLAG:
+                printf("%s=%s ", list->name, list->value.n ? "on" : "off");
+                break;
+            case OPT_SIZE:
+            case OPT_NUMBER:
+                printf("%s=%" PRId64 " ", list->name, list->value.n);
+                break;
+            default:
+                printf("%s=(unkown type) ", list->name);
+                break;
+        }
+        list++;
+    }
+}