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-rw-r--r--src/basic/proc-cmdline.c376
1 files changed, 376 insertions, 0 deletions
diff --git a/src/basic/proc-cmdline.c b/src/basic/proc-cmdline.c
new file mode 100644
index 0000000..0b6fb13
--- /dev/null
+++ b/src/basic/proc-cmdline.c
@@ -0,0 +1,376 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <stdbool.h>
+#include <stddef.h>
+
+#include "alloc-util.h"
+#include "efivars.h"
+#include "extract-word.h"
+#include "fileio.h"
+#include "macro.h"
+#include "parse-util.h"
+#include "proc-cmdline.h"
+#include "process-util.h"
+#include "special.h"
+#include "string-util.h"
+#include "util.h"
+#include "virt.h"
+
+int proc_cmdline(char **ret) {
+ const char *e;
+ assert(ret);
+
+ /* For testing purposes it is sometimes useful to be able to override what we consider /proc/cmdline to be */
+ e = secure_getenv("SYSTEMD_PROC_CMDLINE");
+ if (e) {
+ char *m;
+
+ m = strdup(e);
+ if (!m)
+ return -ENOMEM;
+
+ *ret = m;
+ return 0;
+ }
+
+ if (detect_container() > 0)
+ return get_process_cmdline(1, SIZE_MAX, 0, ret);
+ else
+ return read_one_line_file("/proc/cmdline", ret);
+}
+
+static int proc_cmdline_extract_first(const char **p, char **ret_word, ProcCmdlineFlags flags) {
+ const char *q = *p;
+ int r;
+
+ for (;;) {
+ _cleanup_free_ char *word = NULL;
+ const char *c;
+
+ r = extract_first_word(&q, &word, NULL, EXTRACT_UNQUOTE|EXTRACT_RELAX);
+ if (r < 0)
+ return r;
+ if (r == 0)
+ break;
+
+ /* Filter out arguments that are intended only for the initrd */
+ c = startswith(word, "rd.");
+ if (c) {
+ if (!in_initrd())
+ continue;
+
+ if (FLAGS_SET(flags, PROC_CMDLINE_STRIP_RD_PREFIX)) {
+ r = free_and_strdup(&word, c);
+ if (r < 0)
+ return r;
+ }
+
+ } else if (FLAGS_SET(flags, PROC_CMDLINE_RD_STRICT) && in_initrd())
+ continue; /* And optionally filter out arguments that are intended only for the host */
+
+ *p = q;
+ *ret_word = TAKE_PTR(word);
+ return 1;
+ }
+
+ *p = q;
+ *ret_word = NULL;
+ return 0;
+}
+
+int proc_cmdline_parse_given(const char *line, proc_cmdline_parse_t parse_item, void *data, ProcCmdlineFlags flags) {
+ const char *p;
+ int r;
+
+ assert(parse_item);
+
+ /* The PROC_CMDLINE_VALUE_OPTIONAL flag doesn't really make sense for proc_cmdline_parse(), let's make this
+ * clear. */
+ assert(!FLAGS_SET(flags, PROC_CMDLINE_VALUE_OPTIONAL));
+
+ p = line;
+ for (;;) {
+ _cleanup_free_ char *word = NULL;
+ char *value;
+
+ r = proc_cmdline_extract_first(&p, &word, flags);
+ if (r < 0)
+ return r;
+ if (r == 0)
+ break;
+
+ value = strchr(word, '=');
+ if (value)
+ *(value++) = 0;
+
+ r = parse_item(word, value, data);
+ if (r < 0)
+ return r;
+ }
+
+ return 0;
+}
+
+int proc_cmdline_parse(proc_cmdline_parse_t parse_item, void *data, ProcCmdlineFlags flags) {
+ _cleanup_free_ char *line = NULL;
+ int r;
+
+ assert(parse_item);
+
+ /* We parse the EFI variable first, because later settings have higher priority. */
+
+ if (!FLAGS_SET(flags, PROC_CMDLINE_IGNORE_EFI_OPTIONS)) {
+ r = systemd_efi_options_variable(&line);
+ if (r < 0) {
+ if (r != -ENODATA)
+ log_debug_errno(r, "Failed to get SystemdOptions EFI variable, ignoring: %m");
+ } else {
+ r = proc_cmdline_parse_given(line, parse_item, data, flags);
+ if (r < 0)
+ return r;
+
+ line = mfree(line);
+ }
+ }
+
+ r = proc_cmdline(&line);
+ if (r < 0)
+ return r;
+
+ return proc_cmdline_parse_given(line, parse_item, data, flags);
+}
+
+static bool relaxed_equal_char(char a, char b) {
+ return a == b ||
+ (a == '_' && b == '-') ||
+ (a == '-' && b == '_');
+}
+
+char *proc_cmdline_key_startswith(const char *s, const char *prefix) {
+ assert(s);
+ assert(prefix);
+
+ /* Much like startswith(), but considers "-" and "_" the same */
+
+ for (; *prefix != 0; s++, prefix++)
+ if (!relaxed_equal_char(*s, *prefix))
+ return NULL;
+
+ return (char*) s;
+}
+
+bool proc_cmdline_key_streq(const char *x, const char *y) {
+ assert(x);
+ assert(y);
+
+ /* Much like streq(), but considers "-" and "_" the same */
+
+ for (; *x != 0 || *y != 0; x++, y++)
+ if (!relaxed_equal_char(*x, *y))
+ return false;
+
+ return true;
+}
+
+static int cmdline_get_key(const char *line, const char *key, ProcCmdlineFlags flags, char **ret_value) {
+ _cleanup_free_ char *ret = NULL;
+ bool found = false;
+ const char *p;
+ int r;
+
+ assert(line);
+ assert(key);
+
+ p = line;
+ for (;;) {
+ _cleanup_free_ char *word = NULL;
+
+ r = proc_cmdline_extract_first(&p, &word, flags);
+ if (r < 0)
+ return r;
+ if (r == 0)
+ break;
+
+ if (ret_value) {
+ const char *e;
+
+ e = proc_cmdline_key_startswith(word, key);
+ if (!e)
+ continue;
+
+ if (*e == '=') {
+ r = free_and_strdup(&ret, e+1);
+ if (r < 0)
+ return r;
+
+ found = true;
+
+ } else if (*e == 0 && FLAGS_SET(flags, PROC_CMDLINE_VALUE_OPTIONAL))
+ found = true;
+
+ } else {
+ if (streq(word, key)) {
+ found = true;
+ break; /* we found what we were looking for */
+ }
+ }
+ }
+
+ if (ret_value)
+ *ret_value = TAKE_PTR(ret);
+
+ return found;
+}
+
+int proc_cmdline_get_key(const char *key, ProcCmdlineFlags flags, char **ret_value) {
+ _cleanup_free_ char *line = NULL, *v = NULL;
+ int r;
+
+ /* Looks for a specific key on the kernel command line and (with lower priority) the EFI variable.
+ * Supports three modes:
+ *
+ * a) The "ret_value" parameter is used. In this case a parameter beginning with the "key" string followed by
+ * "=" is searched for, and the value following it is returned in "ret_value".
+ *
+ * b) as above, but the PROC_CMDLINE_VALUE_OPTIONAL flag is set. In this case if the key is found as a separate
+ * word (i.e. not followed by "=" but instead by whitespace or the end of the command line), then this is
+ * also accepted, and "value" is returned as NULL.
+ *
+ * c) The "ret_value" parameter is NULL. In this case a search for the exact "key" parameter is performed.
+ *
+ * In all three cases, > 0 is returned if the key is found, 0 if not. */
+
+ if (isempty(key))
+ return -EINVAL;
+
+ if (FLAGS_SET(flags, PROC_CMDLINE_VALUE_OPTIONAL) && !ret_value)
+ return -EINVAL;
+
+ r = proc_cmdline(&line);
+ if (r < 0)
+ return r;
+
+ if (FLAGS_SET(flags, PROC_CMDLINE_IGNORE_EFI_OPTIONS)) /* Shortcut */
+ return cmdline_get_key(line, key, flags, ret_value);
+
+ r = cmdline_get_key(line, key, flags, ret_value ? &v : NULL);
+ if (r < 0)
+ return r;
+ if (r > 0) {
+ if (ret_value)
+ *ret_value = TAKE_PTR(v);
+
+ return r;
+ }
+
+ line = mfree(line);
+ r = systemd_efi_options_variable(&line);
+ if (r == -ENODATA) {
+ if (ret_value)
+ *ret_value = NULL;
+
+ return false; /* Not found */
+ }
+ if (r < 0)
+ return r;
+
+ return cmdline_get_key(line, key, flags, ret_value);
+}
+
+int proc_cmdline_get_bool(const char *key, bool *ret) {
+ _cleanup_free_ char *v = NULL;
+ int r;
+
+ assert(ret);
+
+ r = proc_cmdline_get_key(key, PROC_CMDLINE_VALUE_OPTIONAL, &v);
+ if (r < 0)
+ return r;
+ if (r == 0) { /* key not specified at all */
+ *ret = false;
+ return 0;
+ }
+
+ if (v) { /* key with parameter passed */
+ r = parse_boolean(v);
+ if (r < 0)
+ return r;
+ *ret = r;
+ } else /* key without parameter passed */
+ *ret = true;
+
+ return 1;
+}
+
+int proc_cmdline_get_key_many_internal(ProcCmdlineFlags flags, ...) {
+ _cleanup_free_ char *line = NULL;
+ bool processing_efi = true;
+ const char *p;
+ va_list ap;
+ int r, ret = 0;
+
+ /* The PROC_CMDLINE_VALUE_OPTIONAL flag doesn't really make sense for proc_cmdline_get_key_many(), let's make
+ * this clear. */
+ assert(!FLAGS_SET(flags, PROC_CMDLINE_VALUE_OPTIONAL));
+
+ /* This call may clobber arguments on failure! */
+
+ if (!FLAGS_SET(flags, PROC_CMDLINE_IGNORE_EFI_OPTIONS)) {
+ r = systemd_efi_options_variable(&line);
+ if (r < 0 && r != -ENODATA)
+ log_debug_errno(r, "Failed to get SystemdOptions EFI variable, ignoring: %m");
+ }
+
+ p = line;
+ for (;;) {
+ _cleanup_free_ char *word = NULL;
+
+ r = proc_cmdline_extract_first(&p, &word, flags);
+ if (r < 0)
+ return r;
+ if (r == 0) {
+ /* We finished with this command line. If this was the EFI one, then let's proceed with the regular one */
+ if (processing_efi) {
+ processing_efi = false;
+
+ line = mfree(line);
+ r = proc_cmdline(&line);
+ if (r < 0)
+ return r;
+
+ p = line;
+ continue;
+ }
+
+ break;
+ }
+
+ va_start(ap, flags);
+
+ for (;;) {
+ char **v;
+ const char *k, *e;
+
+ k = va_arg(ap, const char*);
+ if (!k)
+ break;
+
+ assert_se(v = va_arg(ap, char**));
+
+ e = proc_cmdline_key_startswith(word, k);
+ if (e && *e == '=') {
+ r = free_and_strdup(v, e + 1);
+ if (r < 0) {
+ va_end(ap);
+ return r;
+ }
+
+ ret++;
+ }
+ }
+
+ va_end(ap);
+ }
+
+ return ret;
+}
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