diff options
author | Simon Glass <sjg@chromium.org> | 2023-07-12 18:04:38 +0300 |
---|---|---|
committer | Bin Meng <bmeng@tinylab.org> | 2023-07-17 08:38:34 +0300 |
commit | d07861cc7aa605a64c83bc7fbe1340bc31b2c2cf (patch) | |
tree | 953715e50ae59361b9ecdd71a58dce3403905af6 /boot/bootflow.c | |
parent | 347a845aec18561d36299b0735c47c2b3f45bc71 (diff) | |
download | u-boot-d07861cc7aa605a64c83bc7fbe1340bc31b2c2cf.tar.xz |
bootstd: Add a function to update a command line
The Linux command line consists of a number of words with optional values.
At present U-Boot allows this to be changed using the bootargs environment
variable.
But this is quite painful, since the command line can be very long.
Add a function which can adjust a single field in the command line, so
that it is easier to make changes before booting.
Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Diffstat (limited to 'boot/bootflow.c')
-rw-r--r-- | boot/bootflow.c | 191 |
1 files changed, 191 insertions, 0 deletions
diff --git a/boot/bootflow.c b/boot/bootflow.c index b820678d41..26f26aee38 100644 --- a/boot/bootflow.c +++ b/boot/bootflow.c @@ -610,3 +610,194 @@ static int on_bootargs(const char *name, const char *value, enum env_op op, } U_BOOT_ENV_CALLBACK(bootargs, on_bootargs); #endif + +/** + * copy_in() - Copy a string into a cmdline buffer + * + * @buf: Buffer to copy into + * @end: End of buffer (pointer to char after the end) + * @arg: String to copy from + * @len: Number of chars to copy from @arg (note that this is not usually the + * sane as strlen(arg) since the string may contain following arguments) + * @new_val: Value to put after arg, or BOOTFLOWCL_EMPTY to use an empty value + * with no '=' sign + * Returns: Number of chars written to @buf + */ +static int copy_in(char *buf, char *end, const char *arg, int len, + const char *new_val) +{ + char *to = buf; + + /* copy the arg name */ + if (to + len >= end) + return -E2BIG; + memcpy(to, arg, len); + to += len; + + if (new_val == BOOTFLOWCL_EMPTY) { + /* no value */ + } else { + bool need_quote = strchr(new_val, ' '); + len = strlen(new_val); + + /* need space for value, equals sign and maybe two quotes */ + if (to + 1 + (need_quote ? 2 : 0) + len >= end) + return -E2BIG; + *to++ = '='; + if (need_quote) + *to++ = '"'; + memcpy(to, new_val, len); + to += len; + if (need_quote) + *to++ = '"'; + } + + return to - buf; +} + +int cmdline_set_arg(char *buf, int maxlen, const char *cmdline, + const char *set_arg, const char *new_val, int *posp) +{ + bool found_arg = false; + const char *from; + char *to, *end; + int set_arg_len; + char empty = '\0'; + int ret; + + from = cmdline ?: ∅ + + /* check if the value has quotes inside */ + if (new_val && new_val != BOOTFLOWCL_EMPTY && strchr(new_val, '"')) + return -EBADF; + + set_arg_len = strlen(set_arg); + for (to = buf, end = buf + maxlen; *from;) { + const char *val, *arg_end, *val_end, *p; + bool in_quote; + + if (to >= end) + return -E2BIG; + while (*from == ' ') + from++; + if (!*from) + break; + + /* find the end of this arg */ + val = NULL; + arg_end = NULL; + val_end = NULL; + in_quote = false; + for (p = from;; p++) { + if (in_quote) { + if (!*p) + return -EINVAL; + if (*p == '"') + in_quote = false; + continue; + } + if (*p == '=') { + arg_end = p; + val = p + 1; + } else if (*p == '"') { + in_quote = true; + } else if (!*p || *p == ' ') { + val_end = p; + if (!arg_end) + arg_end = p; + break; + } + } + /* + * At this point val_end points to the end of the value, or the + * last char after the arg name, if there is no label. + * arg_end is the char after the arg name + * val points to the value, or NULL if there is none + * char after the value. + * + * fred=1234 + * ^ ^^ ^ + * from || | + * / \ \ + * arg_end val val_end + */ + log_debug("from %s arg_end %ld val %ld val_end %ld\n", from, + (long)(arg_end - from), (long)(val - from), + (long)(val_end - from)); + + if (to != buf) { + if (to >= end) + return -E2BIG; + *to++ = ' '; + } + + /* if this is the target arg, update it */ + if (!strncmp(from, set_arg, arg_end - from)) { + if (!buf) { + bool has_quote = val_end[-1] == '"'; + + /* + * exclude any start/end quotes from + * calculations + */ + if (!val) + val = val_end; + *posp = val - cmdline + has_quote; + return val_end - val - 2 * has_quote; + } + found_arg = true; + if (!new_val) { + /* delete this arg */ + from = val_end + (*val_end == ' '); + log_debug("delete from: %s\n", from); + if (to != buf) + to--; /* drop the space we added */ + continue; + } + + ret = copy_in(to, end, from, arg_end - from, new_val); + if (ret < 0) + return ret; + to += ret; + + /* if not the target arg, copy it unchanged */ + } else if (to) { + int len; + + len = val_end - from; + if (to + len >= end) + return -E2BIG; + memcpy(to, from, len); + to += len; + } + from = val_end; + } + + /* If we didn't find the arg, add it */ + if (!found_arg) { + /* trying to delete something that is not there */ + if (!new_val || !buf) + return -ENOENT; + if (to >= end) + return -E2BIG; + + /* add a space to separate it from the previous arg */ + if (to != buf && to[-1] != ' ') + *to++ = ' '; + ret = copy_in(to, end, set_arg, set_arg_len, new_val); + log_debug("ret=%d, to: %s buf: %s\n", ret, to, buf); + if (ret < 0) + return ret; + to += ret; + } + + /* delete any trailing space */ + if (to > buf && to[-1] == ' ') + to--; + + if (to >= end) + return -E2BIG; + *to++ = '\0'; + + return to - buf; +} |