diff options
Diffstat (limited to 'init/main.c')
| -rw-r--r-- | init/main.c | 97 |
1 files changed, 96 insertions, 1 deletions
diff --git a/init/main.c b/init/main.c index 07a3116811c5..b84818ad9685 100644 --- a/init/main.c +++ b/init/main.c @@ -906,6 +906,101 @@ static void __init early_numa_node_init(void) #endif } +#define KERNEL_CMDLINE_PREFIX "Kernel command line: " +#define KERNEL_CMDLINE_PREFIX_LEN (sizeof(KERNEL_CMDLINE_PREFIX) - 1) +#define KERNEL_CMDLINE_CONTINUATION " \\" +#define KERNEL_CMDLINE_CONTINUATION_LEN (sizeof(KERNEL_CMDLINE_CONTINUATION) - 1) + +#define MIN_CMDLINE_LOG_WRAP_IDEAL_LEN (KERNEL_CMDLINE_PREFIX_LEN + \ + KERNEL_CMDLINE_CONTINUATION_LEN) +#define CMDLINE_LOG_WRAP_IDEAL_LEN (CONFIG_CMDLINE_LOG_WRAP_IDEAL_LEN > \ + MIN_CMDLINE_LOG_WRAP_IDEAL_LEN ? \ + CONFIG_CMDLINE_LOG_WRAP_IDEAL_LEN : \ + MIN_CMDLINE_LOG_WRAP_IDEAL_LEN) + +#define IDEAL_CMDLINE_LEN (CMDLINE_LOG_WRAP_IDEAL_LEN - KERNEL_CMDLINE_PREFIX_LEN) +#define IDEAL_CMDLINE_SPLIT_LEN (IDEAL_CMDLINE_LEN - KERNEL_CMDLINE_CONTINUATION_LEN) + +/** + * print_kernel_cmdline() - Print the kernel cmdline with wrapping. + * @cmdline: The cmdline to print. + * + * Print the kernel command line, trying to wrap based on the Kconfig knob + * CONFIG_CMDLINE_LOG_WRAP_IDEAL_LEN. + * + * Wrapping is based on spaces, ignoring quotes. All lines are prefixed + * with "Kernel command line: " and lines that are not the last line have + * a " \" suffix added to them. The prefix and suffix count towards the + * line length for wrapping purposes. The ideal length will be exceeded + * if no appropriate place to wrap is found. + * + * Example output if CONFIG_CMDLINE_LOG_WRAP_IDEAL_LEN is 40: + * Kernel command line: loglevel=7 \ + * Kernel command line: init=/sbin/init \ + * Kernel command line: root=PARTUUID=8c3efc1a-768b-6642-8d0c-89eb782f19f0/PARTNROFF=1 \ + * Kernel command line: rootwait ro \ + * Kernel command line: my_quoted_arg="The \ + * Kernel command line: quick brown fox \ + * Kernel command line: jumps over the \ + * Kernel command line: lazy dog." + */ +static void __init print_kernel_cmdline(const char *cmdline) +{ + size_t len; + + /* Config option of 0 or anything longer than the max disables wrapping */ + if (CONFIG_CMDLINE_LOG_WRAP_IDEAL_LEN == 0 || + IDEAL_CMDLINE_LEN >= COMMAND_LINE_SIZE - 1) { + pr_notice("%s%s\n", KERNEL_CMDLINE_PREFIX, cmdline); + return; + } + + len = strlen(cmdline); + while (len > IDEAL_CMDLINE_LEN) { + const char *first_space; + const char *prev_cutoff; + const char *cutoff; + int to_print; + size_t used; + + /* Find the last ' ' that wouldn't make the line too long */ + prev_cutoff = NULL; + cutoff = cmdline; + while (true) { + cutoff = strchr(cutoff + 1, ' '); + if (!cutoff || cutoff - cmdline > IDEAL_CMDLINE_SPLIT_LEN) + break; + prev_cutoff = cutoff; + } + if (prev_cutoff) + cutoff = prev_cutoff; + else if (!cutoff) + break; + + /* Find the beginning and end of the string of spaces */ + first_space = cutoff; + while (first_space > cmdline && first_space[-1] == ' ') + first_space--; + to_print = first_space - cmdline; + while (*cutoff == ' ') + cutoff++; + used = cutoff - cmdline; + + /* If the whole string is used, break and do the final printout */ + if (len == used) + break; + + if (to_print) + pr_notice("%s%.*s%s\n", KERNEL_CMDLINE_PREFIX, + to_print, cmdline, KERNEL_CMDLINE_CONTINUATION); + + len -= used; + cmdline += used; + } + if (len) + pr_notice("%s%s\n", KERNEL_CMDLINE_PREFIX, cmdline); +} + asmlinkage __visible __init __no_sanitize_address __noreturn __no_stack_protector void start_kernel(void) { @@ -942,7 +1037,7 @@ void start_kernel(void) early_numa_node_init(); boot_cpu_hotplug_init(); - pr_notice("Kernel command line: %s\n", saved_command_line); + print_kernel_cmdline(saved_command_line); /* parameters may set static keys */ parse_early_param(); after_dashes = parse_args("Booting kernel", |