From: Paulo de Rezende Pinatti <ppinatti@xxxxxxxxxxxxx>
Introduce two utility functions to parse a kernel command
line string according to the kernel code parsing rules in
order to enable the caller to perform operations such as
verifying whether certain argument=value combinations are
present or retrieving an argument's value.
Signed-off-by: Paulo de Rezende Pinatti <ppinatti@xxxxxxxxxxxxx>
Reviewed-by: Boris Fiuczynski <fiuczy@xxxxxxxxxxxxx>
---
src/libvirt_private.syms | 2 +
src/util/virutil.c | 173 +++++++++++++++++++++++++++++++++++++++
src/util/virutil.h | 18 ++++
tests/utiltest.c | 130 +++++++++++++++++++++++++++++
4 files changed, 323 insertions(+)
diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
index 935ef7303b..25b22a3e3f 100644
--- a/src/libvirt_private.syms
+++ b/src/libvirt_private.syms
@@ -3428,6 +3428,8 @@ virHostGetDRMRenderNode;
virHostHasIOMMU;
virIndexToDiskName;
virIsDevMapperDevice;
+virKernelCmdlineGetValue;
+virKernelCmdlineMatchParam;
virMemoryLimitIsSet;
virMemoryLimitTruncate;
virMemoryMaxValue;
diff --git a/src/util/virutil.c b/src/util/virutil.c
index fb46501142..264aae8d01 100644
--- a/src/util/virutil.c
+++ b/src/util/virutil.c
@@ -1725,6 +1725,179 @@ virHostGetDRMRenderNode(void)
return ret;
}
+
+#define VIR_IS_CMDLINE_SPACE(value) \
+ (g_ascii_isspace(value) || (unsigned char) value == 160)
+
+
+static bool virKernelArgsAreEqual(const char *arg1,
+ const char *arg2,
+ size_t n)
+{
+ size_t i;
+
+ for (i = 0; i < n; i++) {
+ if ((arg1[i] == '-' && arg2[i] == '_') ||
+ (arg1[i] == '_' && arg2[i] == '-') || (arg1[i] == arg2[i])) {
+ if (arg1[i] == '\0')
+ return true;
+ continue;
+ }
+ return false;
+ }
+ return true;
+}
+
+
+/*
+ * Parse the kernel cmdline and store the value of @arg in @val
+ * which can be NULL if @arg has no value or if it's not found.
+ * In addition, store in @next the address right after
+ * @arg=@value for possible further processing.
+ *
+ * @arg: kernel command line argument
+ * @cmdline: kernel command line string to be checked for @arg
+ * @val: pointer to hold retrieved value of @arg
+ * @next: pointer to hold address right after @arg=@val, will
+ * point to the string's end (NULL) in case @arg is not found
+ *
+ * Returns 0 if @arg is present in @cmdline, 1 otherwise
+ */
+int virKernelCmdlineGetValue(const char *arg,
+ const char *cmdline,
+ char **val,
+ const char **next)
+{
+ size_t i = 0, param_i;
+ size_t arg_len = strlen(arg);
+ bool is_quoted, match;
+
+ *next = cmdline;
+ *val = NULL;
+
+ while (cmdline[i] != '\0') {
+ /* remove leading spaces */
+ while (VIR_IS_CMDLINE_SPACE(cmdline[i]))
+ i++;
+ if (cmdline[i] == '"') {
+ i++;
+ is_quoted = true;
+ } else {
+ is_quoted = false;
+ }
+ for (param_i = i; cmdline[param_i]; param_i++) {
+ if ((VIR_IS_CMDLINE_SPACE(cmdline[param_i]) && !is_quoted) ||
+ cmdline[param_i] == '=')
+ break;
+ if (cmdline[param_i] == '"')
+ is_quoted = !is_quoted;
+ }
+ if (param_i-i == arg_len && virKernelArgsAreEqual(cmdline+i, arg, arg_len))
+ match = true;
+ else
+ match = false;
+ /* arg has no value */
+ if (cmdline[param_i] != '=') {
+ if (match) {
+ *next = cmdline+param_i;
+ return 0;
+ }
+ i = param_i;
+ continue;
+ }
+ param_i++;
+ if (cmdline[param_i] == '\0')
+ break;
+
+ if (cmdline[param_i] == '"') {
+ param_i++;
+ is_quoted = !is_quoted;
+ }
+ i = param_i;
+
+ for (; cmdline[param_i]; param_i++) {
+ if (VIR_IS_CMDLINE_SPACE(cmdline[param_i]) && !is_quoted)
+ break;
+ if (cmdline[param_i] == '"')
+ is_quoted = !is_quoted;
+ }
+ if (match) {
+ *next = cmdline+param_i;
+ if (cmdline[param_i-1] == '"')
+ *val = g_strndup(cmdline+i, param_i-i-1);
+ else
+ *val = g_strndup(cmdline+i, param_i-i);
+ return 0;
+ }
+ i = param_i;
+ }
+ *next = cmdline+i;
+ return 1;
+}
+
+
+#define VIR_CMDLINE_STR_CMP(kernel_val, caller_val, flags) \
+ (((flags & VIR_KERNEL_CMDLINE_FLAGS_CMP_EQ) && \
+ STREQ(kernel_val, caller_val)) || ((flags & VIR_KERNEL_CMDLINE_FLAGS_CMP_PREFIX) && \
+ STRPREFIX(kernel_val, caller_val)))
+
+
+/*
+ * Try to match the provided kernel cmdline string with the provided @arg
+ * and the list @values of possible values according to the matching strategy
+ * defined in @flags. Possible options include:
+ * - VIR_KERNEL_CMDLINE_FLAGS_CMP_PREFIX: do a substring comparison of values
+ * (uses size of value provided as input)
+ * - VIR_KERNEL_CMDLINE_FLAGS_CMP_EQ: do a strict string comparison
+ * - VIR_KERNEL_CMDLINE_FLAGS_SEARCH_STICKY: first positive match satifies search
+ * (in case of multiple argument occurrences)
+ * - VIR_KERNEL_CMDLINE_FLAGS_SEARCH_LAST: use the result of last argument occurence
+ * (in case of multiple argument occurrences)
+ *
+ *
+ * @cmdline: kernel command line string to be checked for @arg
+ * @arg: kernel command line argument
+ * @values: array of possible values to match @arg
+ * @len_values: size of array, it can be 0 meaning a match will be positive if the
+ * argument has no value.
+ * @flags: flag mask defining the strategy for matching and comparing
+ *
+ * Returns true if a match is found, false otherwise
+ */
+bool virKernelCmdlineMatchParam(const char *cmdline,
+ const char *arg,
+ const char **values,
+ size_t len_values,
+ virKernelCmdlineFlags flags)
+{
+ bool match = false;
+ size_t i;
+ const char *next = cmdline;
+ g_autofree char *kval = NULL;
+
+ while (next[0] != '\0') {
+ VIR_FREE(kval);
+ if (virKernelCmdlineGetValue(arg, next, &kval, &next) != 0)
+ break;
+ if (!kval) {
+ match = (len_values == 0) ? true : false;
+ } else {
+ match = false;
+ for (i = 0; i < len_values; i++) {
+ if (VIR_CMDLINE_STR_CMP(kval, values[i], flags)) {
+ match = true;
+ break;
+ }
+ }
+ }
+ if (match && (flags & VIR_KERNEL_CMDLINE_FLAGS_SEARCH_STICKY))
+ break;
+ }
+
+ return match;
+}
+
+
/*
* Get a password from the console input stream.
* The caller must free the returned password.
diff --git a/src/util/virutil.h b/src/util/virutil.h
index 49b4bf440f..1edb415fbe 100644
--- a/src/util/virutil.h
+++ b/src/util/virutil.h
@@ -147,6 +147,24 @@ bool virHostHasIOMMU(void);
char *virHostGetDRMRenderNode(void) G_GNUC_NO_INLINE;
+typedef enum {
+ VIR_KERNEL_CMDLINE_FLAGS_CMP_PREFIX = 1,
+ VIR_KERNEL_CMDLINE_FLAGS_CMP_EQ = 2,
+ VIR_KERNEL_CMDLINE_FLAGS_SEARCH_STICKY = 4,
+ VIR_KERNEL_CMDLINE_FLAGS_SEARCH_LAST = 8,
+} virKernelCmdlineFlags;
+
+int virKernelCmdlineGetValue(const char *arg,
+ const char *cmdline,
+ char **val,
+ const char **next);
+
+bool virKernelCmdlineMatchParam(const char *cmdline,
+ const char *arg,
+ const char **values,
+ size_t len_values,
+ virKernelCmdlineFlags flags);
+
/**
* VIR_ASSIGN_IS_OVERFLOW:
* @rvalue: value that is checked (evaluated twice)
diff --git a/tests/utiltest.c b/tests/utiltest.c
index 5ae04585cb..1edc6a728e 100644
--- a/tests/utiltest.c
+++ b/tests/utiltest.c
@@ -254,6 +254,134 @@ testOverflowCheckMacro(const void *data G_GNUC_UNUSED)
}
+struct testKernelCmdlineGetValueData
+{
+ const char *cmdline;
+ const char *arg;
+ int rc;
+ const char *val;
+ size_t next;
+};
+
+static struct testKernelCmdlineGetValueData kEntries[] = {
+ { "arg1 arg2 arg3=val1", "arg4", 1, NULL, 19 },
+ { "arg1=val1 arg2 arg3=val3 arg4", "arg2", 0, NULL, 14 },
+ { "arg1=val1 arg2 arg3=val3 arg4", "arg3", 0, "val3", 24 },
+ { "arg1=val1 arg2 arg-3=val3 arg4", "arg_3", 0, "val3", 25 },
+ { "arg1=val1 arg2 arg_3=val3 arg4", "arg-3", 0, "val3", 25 },
+ { "arg1=val1 arg2 arg_3=val3 arg4", "arg_3", 0, "val3", 25 },
+ { "arg1=val1 arg2 arg-3=val3 arg4", "arg-3", 0, "val3", 25 },
+ { "arg1=val1 arg2=\"value with spaces\" arg3=val3", "arg2", 0, "value with spaces", 34 },
+ { "arg1=val1 arg2=\"value with spaces\" arg3=val3", "arg3", 0, "val3", 44 },
+ { "arg1=val1 \"arg2=value with spaces\" arg3=val3", "arg2", 0, "value with spaces", 34 },
+ { "arg1=val1 \"arg2=value with spaces\" arg3=val3", "arg3", 0, "val3", 44 },
+ { "arg1=val1 arg2=\"val\"ue arg3", "arg2", 0, "val\"ue", 22 },
+ { "arg1=val1 arg2=\"val\"ue arg3\" escaped=val2\"", "arg3\" escaped", 0, "val2", 42 },
+ { "arg1=val1 arg2longer=someval arg2=val2 arg3", "arg2", 0, "val2", 38 },
+};
+
+static int
+testKernelCmdlineGetValue(const void *data G_GNUC_UNUSED)
+{
+ int rc;
+ char *val = NULL;
+ const char *next;
+ size_t i;
+
+ for (i = 0; i < G_N_ELEMENTS(kEntries); ++i) {
+ VIR_FREE(val);
+
+ rc = virKernelCmdlineGetValue(kEntries[i].arg, kEntries[i].cmdline,
+ &val, &next);
+
+ if (rc != kEntries[i].rc || STRNEQ_NULLABLE(val, kEntries[i].val) ||
+ (next - kEntries[i].cmdline) != kEntries[i].next) {
+ VIR_TEST_DEBUG("\nKernel cmdline [%s]", kEntries[i].cmdline);
+ VIR_TEST_DEBUG("Kernel argument [%s]", kEntries[i].arg);
+ VIR_TEST_DEBUG("Expect rc [%d]", kEntries[i].rc);
+ VIR_TEST_DEBUG("Actual rc [%d]", rc);
+ VIR_TEST_DEBUG("Expect value [%s]", kEntries[i].val);
+ VIR_TEST_DEBUG("Actual value [%s]", val);
+ VIR_TEST_DEBUG("Expect next index [%lu]", kEntries[i].next);
+ VIR_TEST_DEBUG("Actual next index [%lu]",
+ (size_t)(next - kEntries[i].cmdline));
+
+ VIR_FREE(val);
+
+ return -1;
+ }
+ }
+
+ VIR_FREE(val);
+
+ return 0;
+}
+
+
+struct testKernelCmdlineMatchData
+{
+ const char *cmdline;
+ const char *arg;
+ const char *values[2];
+ virKernelCmdlineFlags flags;
+ bool result;
+};
+
+static struct testKernelCmdlineMatchData kMatchEntries[] = {
+ {"arg1 myarg=no arg2=val2 myarg=yes arg4=val4 myarg=no arg5", "myarg", {"1", "y"}, VIR_KERNEL_CMDLINE_FLAGS_SEARCH_STICKY | VIR_KERNEL_CMDLINE_FLAGS_CMP_EQ, false },
+ {"arg1 myarg=no arg2=val2 myarg=yes arg4=val4 myarg=no arg5", "myarg", {"on", "yes"}, VIR_KERNEL_CMDLINE_FLAGS_SEARCH_STICKY | VIR_KERNEL_CMDLINE_FLAGS_CMP_EQ, true },
+ {"arg1 myarg=no arg2=val2 myarg=yes arg4=val4 myarg=no arg5", "myarg", {"1", "y"}, VIR_KERNEL_CMDLINE_FLAGS_SEARCH_STICKY | VIR_KERNEL_CMDLINE_FLAGS_CMP_PREFIX, true },
+ {"arg1 myarg=no arg2=val2 myarg=yes arg4=val4 myarg=no arg5", "myarg", {"a", "b"}, VIR_KERNEL_CMDLINE_FLAGS_SEARCH_STICKY | VIR_KERNEL_CMDLINE_FLAGS_CMP_PREFIX, false },
+ {"arg1 myarg=no arg2=val2 myarg=yes arg4=val4 myarg=no arg5", "myarg", {"on", "yes"}, VIR_KERNEL_CMDLINE_FLAGS_SEARCH_LAST | VIR_KERNEL_CMDLINE_FLAGS_CMP_EQ, false},
+ {"arg1 myarg=no arg2=val2 myarg=yes arg4=val4 myarg=no arg5", "myarg", {"1", "y"}, VIR_KERNEL_CMDLINE_FLAGS_SEARCH_LAST | VIR_KERNEL_CMDLINE_FLAGS_CMP_PREFIX, false},
+ {"arg1 myarg=no arg2=val2 arg4=val4 myarg=yes arg5", "myarg", {"on", "yes"}, VIR_KERNEL_CMDLINE_FLAGS_SEARCH_LAST | VIR_KERNEL_CMDLINE_FLAGS_CMP_EQ, true },
+ {"arg1 myarg=no arg2=val2 arg4=val4 myarg=yes arg5", "myarg", {"1", "y"}, VIR_KERNEL_CMDLINE_FLAGS_SEARCH_LAST | VIR_KERNEL_CMDLINE_FLAGS_CMP_PREFIX, true },
+ {"arg1 myarg=no arg2=val2 arg4=val4 myarg arg5", "myarg", {NULL, NULL}, VIR_KERNEL_CMDLINE_FLAGS_SEARCH_LAST, true },
+ {"arg1 myarg arg2=val2 arg4=val4 myarg=yes arg5", "myarg", {NULL, NULL}, VIR_KERNEL_CMDLINE_FLAGS_SEARCH_STICKY, true },
+ {"arg1 myarg arg2=val2 arg4=val4 myarg=yes arg5", "myarg", {NULL, NULL}, VIR_KERNEL_CMDLINE_FLAGS_SEARCH_LAST, false },
+};
+
+
+static int
+testKernelCmdlineMatchParam(const void *data G_GNUC_UNUSED)
+{
+ bool result;
+ size_t i, lenValues;
+
+ for (i = 0; i < G_N_ELEMENTS(kMatchEntries); ++i) {
+ if (kMatchEntries[i].values[0] == NULL)
+ lenValues = 0;
+ else
+ lenValues = G_N_ELEMENTS(kMatchEntries[i].values);
+
+ result = virKernelCmdlineMatchParam(kMatchEntries[i].cmdline,
+ kMatchEntries[i].arg,
+ kMatchEntries[i].values,
+ lenValues,
+ kMatchEntries[i].flags);
+
+ if (result != kMatchEntries[i].result) {
+ VIR_TEST_DEBUG("\nKernel cmdline [%s]", kMatchEntries[i].cmdline);
+ VIR_TEST_DEBUG("Kernel argument [%s]", kMatchEntries[i].arg);
+ VIR_TEST_DEBUG("Kernel values [%s] [%s]", kMatchEntries[i].values[0],
+ kMatchEntries[i].values[1]);
+ if (kMatchEntries[i].flags & VIR_KERNEL_CMDLINE_FLAGS_CMP_PREFIX)
+ VIR_TEST_DEBUG("Flag [VIR_KERNEL_CMDLINE_FLAGS_CMP_PREFIX]");
+ if (kMatchEntries[i].flags & VIR_KERNEL_CMDLINE_FLAGS_CMP_EQ)
+ VIR_TEST_DEBUG("Flag [VIR_KERNEL_CMDLINE_FLAGS_CMP_EQ]");
+ if (kMatchEntries[i].flags & VIR_KERNEL_CMDLINE_FLAGS_SEARCH_STICKY)
+ VIR_TEST_DEBUG("Flag [VIR_KERNEL_CMDLINE_FLAGS_SEARCH_STICKY]");
+ if (kMatchEntries[i].flags & VIR_KERNEL_CMDLINE_FLAGS_SEARCH_LAST)
+ VIR_TEST_DEBUG("Flag [VIR_KERNEL_CMDLINE_FLAGS_SEARCH_LAST]");
+ VIR_TEST_DEBUG("Expect result [%d]", kMatchEntries[i].result);
+ VIR_TEST_DEBUG("Actual result [%d]", result);
+
+ return -1;
+ }
+ }
+
+ return 0;
+}
static int
@@ -277,6 +405,8 @@ mymain(void)
DO_TEST(ParseVersionString);
DO_TEST(RoundValueToPowerOfTwo);
DO_TEST(OverflowCheckMacro);
+ DO_TEST(KernelCmdlineGetValue);
+ DO_TEST(KernelCmdlineMatchParam);
return result == 0 ? EXIT_SUCCESS : EXIT_FAILURE;
}
--
2.25.1
