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>
Signed-off-by: Boris Fiuczynski <fiuczy@xxxxxxxxxxxxx>
---
src/libvirt_private.syms | 2 +
src/util/virutil.c | 169 +++++++++++++++++++++++++++++++++++++++
src/util/virutil.h | 17 ++++
tests/utiltest.c | 141 ++++++++++++++++++++++++++++++++
4 files changed, 329 insertions(+)
diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
index a6af44fe1c..a206a943c5 100644
--- a/src/libvirt_private.syms
+++ b/src/libvirt_private.syms
@@ -3433,6 +3433,8 @@ virHostGetDRMRenderNode;
virHostHasIOMMU;
virIndexToDiskName;
virIsDevMapperDevice;
+virKernelCmdlineMatchParam;
+virKernelCmdlineNextParam;
virMemoryLimitIsSet;
virMemoryLimitTruncate;
virMemoryMaxValue;
diff --git a/src/util/virutil.c b/src/util/virutil.c
index fb46501142..749c9d7116 100644
--- a/src/util/virutil.c
+++ b/src/util/virutil.c
@@ -1725,6 +1725,175 @@ virHostGetDRMRenderNode(void)
return ret;
}
+
+static const char *virKernelCmdlineSkipDbQuote(const char *cmdline,
+ bool *is_quoted)
+{
+ if (cmdline[0] == '"') {
+ *is_quoted = !(*is_quoted);
+ cmdline++;
+ }
+ return cmdline;
+}
+
+
+static size_t virKernelCmdlineSearchForward(const char *cmdline,
+ bool *is_quoted,
+ bool include_equal)
+{
+ size_t index;
+
+ for (index = 0; cmdline[index]; index++) {
+ if ((!(*is_quoted) && g_ascii_isspace(cmdline[index])) ||
+ (include_equal && cmdline[index] == '='))
+ break;
+ virKernelCmdlineSkipDbQuote(cmdline + index, is_quoted);
+ }
+ return index;
+}
+
+
+static size_t virKernelCmdlineNextSpace(const char *cmdline,
+ bool *is_quoted)
+{
+ return virKernelCmdlineSearchForward(cmdline, is_quoted, false);
+}
+
+
+static size_t virKernelCmdlineNextSpaceOrEqual(const char *cmdline,
+ bool *is_quoted)
+{
+ return virKernelCmdlineSearchForward(cmdline, is_quoted, true);
+}
+
+
+static char* virKernelArgNormalize(const char *arg)
+{
+ return virStringReplace(arg, "_", "-");
+}
+
+
+static char* virKernelCmdlineArgNormalize(const char *cmdline, size_t offset)
+{
+ g_autofree char *param = g_strndup((cmdline), offset);
+
+ return virKernelArgNormalize(param);
+}
+
+
+/*
+ * Parse the kernel cmdline and store the next parameter in @param
+ * and the value of @param in @val which can be NULL if @param has
+ * no value. In addition returns the address right after @param=@value
+ * for possible further processing.
+ *
+ * @cmdline: kernel command line string to be checked for next parameter
+ * @param: pointer to hold retrieved parameter, will be NULL if none found
+ * @val: pointer to hold retrieved value of @param
+ *
+ * Returns a pointer to address right after @param=@val in the
+ * kernel command line, will point to the string's end (NULL)
+ * in case no next parameter is found
+ */
+const char *virKernelCmdlineNextParam(const char *cmdline,
+ char **param,
+ char **val)
+{
+ size_t offset;
+ bool is_quoted = false;
+ *param = NULL;
+ *val = NULL;
+
+ virSkipSpaces(&cmdline);
+ cmdline = virKernelCmdlineSkipDbQuote(cmdline, &is_quoted);
+ offset = virKernelCmdlineNextSpaceOrEqual(cmdline, &is_quoted);
+ if (offset == 0)
+ return cmdline;
+
+ *param = virKernelCmdlineArgNormalize(cmdline, offset);
+ cmdline = cmdline + offset;
+ /* param has no value */
+ if (*cmdline != '=')
+ return cmdline;
+
+ cmdline = virKernelCmdlineSkipDbQuote(++cmdline, &is_quoted);
+ offset = virKernelCmdlineNextSpace(cmdline, &is_quoted);
+ if (cmdline[offset-1] == '"')
+ *val = g_strndup(cmdline, offset-1);
+ else
+ *val = g_strndup(cmdline, offset);
+
+ return cmdline + offset;
+}
+
+
+#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 of values
+ * - 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 *norm_arg = virKernelArgNormalize(arg);
+ g_autofree char *kparam = NULL;
+ g_autofree char *kval = NULL;
+
+ while (next[0] != '\0') {
+ VIR_FREE(kparam);
+ VIR_FREE(kval);
+ next = virKernelCmdlineNextParam(next, &kparam, &kval);
+ if (!kparam)
+ break;
+ if (STRNEQ(kparam, norm_arg))
+ continue;
+ 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..7499b78153 100644
--- a/src/util/virutil.h
+++ b/src/util/virutil.h
@@ -147,6 +147,23 @@ 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;
+
+const char *virKernelCmdlineNextParam(const char *cmdline,
+ char **param,
+ char **val);
+
+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..01fb8c89f5 100644
--- a/tests/utiltest.c
+++ b/tests/utiltest.c
@@ -254,6 +254,145 @@ testOverflowCheckMacro(const void *data G_GNUC_UNUSED)
}
+struct testKernelCmdlineNextParamData
+{
+ const char *cmdline;
+ const char *param;
+ const char *val;
+ const char *next;
+};
+
+static struct testKernelCmdlineNextParamData kEntries[] = {
+ { "arg1 arg2 arg3=val1", "arg1", NULL, " arg2 arg3=val1" },
+ { "arg1=val1 arg2 arg3=val3 arg4", "arg1", "val1", " arg2 arg3=val3 arg4" },
+ { "arg3=val3 ", "arg3", "val3", " " },
+ { "arg3=val3", "arg3", "val3", "" },
+ { "arg-3=val3 arg4", "arg-3", "val3", " arg4" },
+ { "arg_3=val3 arg4", "arg-3", "val3", " arg4" },
+ { " arg_3=val3 arg4", "arg-3", "val3", " arg4" },
+ { " arg-3=val3 arg4", "arg-3", "val3", " arg4" },
+ { "arg2=\"value with spaces\" arg3=val3", "arg2", "value with spaces", " arg3=val3" },
+ { " arg2=\"value with spaces\" arg3=val3", "arg2", "value with spaces", " arg3=val3" },
+ { " \"arg2=value with spaces\" arg3=val3", "arg2", "value with spaces", " arg3=val3" },
+ { "arg2=\"val\"ue arg3", "arg2", "val\"ue", " arg3" },
+ { " arg3\" escaped=val2\"", "arg3\" escaped", "val2", "" },
+ { " arg2longer=someval arg2=val2 arg3 ", "arg2longer", "someval", " arg2=val2 arg3 " },
+ { "=val1 arg2=val2", NULL, NULL, "=val1 arg2=val2" },
+ { " ", NULL, NULL, "" },
+ { "", NULL, NULL, "" },
+};
+
+static int
+testKernelCmdlineNextParam(const void *data G_GNUC_UNUSED)
+{
+ char *param = NULL;
+ char *val = NULL;
+ const char *next;
+ size_t i;
+
+ for (i = 0; i < G_N_ELEMENTS(kEntries); ++i) {
+ VIR_FREE(param);
+ VIR_FREE(val);
+
+ next = virKernelCmdlineNextParam(kEntries[i].cmdline, ¶m, &val);
+
+ if (STRNEQ_NULLABLE(param, kEntries[i].param) ||
+ STRNEQ_NULLABLE(val, kEntries[i].val) ||
+ STRNEQ(next, kEntries[i].next)) {
+ VIR_TEST_DEBUG("\nKernel cmdline [%s]", kEntries[i].cmdline);
+ VIR_TEST_DEBUG("Expect param [%s]", kEntries[i].param);
+ VIR_TEST_DEBUG("Actual param [%s]", param);
+ VIR_TEST_DEBUG("Expect value [%s]", kEntries[i].val);
+ VIR_TEST_DEBUG("Actual value [%s]", val);
+ VIR_TEST_DEBUG("Expect next [%s]", kEntries[i].next);
+ VIR_TEST_DEBUG("Actual next [%s]", next);
+
+ VIR_FREE(param);
+ VIR_FREE(val);
+
+ return -1;
+ }
+ }
+
+ VIR_FREE(param);
+ 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 },
+ {"arg1 my-arg=no arg2=val2 arg4=val4 my_arg=yes arg5", "my-arg", {"on", "yes"}, VIR_KERNEL_CMDLINE_FLAGS_SEARCH_LAST | VIR_KERNEL_CMDLINE_FLAGS_CMP_EQ, true },
+ {"arg1 my-arg=no arg2=val2 arg4=val4 my_arg=yes arg5 ", "my-arg", {"on", "yes"}, VIR_KERNEL_CMDLINE_FLAGS_SEARCH_LAST | VIR_KERNEL_CMDLINE_FLAGS_CMP_EQ, true },
+ {"arg1 my-arg arg2=val2 arg4=val4 my_arg=yes arg5", "my_arg", {NULL, NULL}, VIR_KERNEL_CMDLINE_FLAGS_SEARCH_STICKY, true },
+ {"arg1 my-arg arg2=val2 arg4=val4 my-arg=yes arg5", "my_arg", {NULL, NULL}, VIR_KERNEL_CMDLINE_FLAGS_SEARCH_STICKY, true },
+ {"=val1 my-arg arg2=val2 arg4=val4 my-arg=yes arg5", "myarg", {NULL, NULL}, VIR_KERNEL_CMDLINE_FLAGS_SEARCH_STICKY, false },
+ {"arg1 arg2=", "arg2", {"", ""}, VIR_KERNEL_CMDLINE_FLAGS_SEARCH_LAST | VIR_KERNEL_CMDLINE_FLAGS_CMP_EQ, true },
+ {" ", "myarg", {NULL, NULL}, VIR_KERNEL_CMDLINE_FLAGS_SEARCH_LAST, false },
+ {"", "", {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 +416,8 @@ mymain(void)
DO_TEST(ParseVersionString);
DO_TEST(RoundValueToPowerOfTwo);
DO_TEST(OverflowCheckMacro);
+ DO_TEST(KernelCmdlineNextParam);
+ DO_TEST(KernelCmdlineMatchParam);
return result == 0 ? EXIT_SUCCESS : EXIT_FAILURE;
}
--
2.25.4
