diff options
Diffstat (limited to 'lib/bootconfig.c')
| -rw-r--r-- | lib/bootconfig.c | 268 |
1 files changed, 240 insertions, 28 deletions
diff --git a/lib/bootconfig.c b/lib/bootconfig.c index e88d0221a826..89c88e359179 100644 --- a/lib/bootconfig.c +++ b/lib/bootconfig.c @@ -17,9 +17,15 @@ #include <linux/bug.h> #include <linux/ctype.h> #include <linux/errno.h> -#include <linux/kernel.h> +#include <linux/cache.h> +#include <linux/compiler.h> +#include <linux/init.h> +#include <linux/moduleparam.h> +#include <linux/printk.h> +#include <linux/sprintf.h> #include <linux/memblock.h> #include <linux/string.h> +#include <asm/setup.h> /* COMMAND_LINE_SIZE */ #ifdef CONFIG_BOOT_CONFIG_EMBED /* embedded_bootconfig_data is defined in bootconfig-data.S */ @@ -32,7 +38,129 @@ const char * __init xbc_get_embedded_bootconfig(size_t *size) return (*size) ? embedded_bootconfig_data : NULL; } #endif -#endif + +#ifdef CONFIG_CMDLINE_FROM_BOOTCONFIG +/* embedded_kernel_cmdline is defined in embedded-cmdline.S */ +extern __visible const char embedded_kernel_cmdline[]; +extern __visible const char embedded_kernel_cmdline_end[]; + +/* Set once the embedded cmdline has actually been prepended. */ +static bool xbc_cmdline_applied __initdata; + +/* + * str_prepend() - Prepend @src in front of the string in @dst, in place + * @dst: NUL-terminated destination buffer, currently @dst_len bytes long + * @dst_len: length of the current @dst string (excluding its NUL) + * @src: bytes to prepend (not NUL-terminated) + * @src_len: number of bytes from @src to prepend + * + * The caller must guarantee @dst has room for src_len + dst_len + 1 bytes. + * Moving dst_len + 1 bytes carries @dst's NUL terminator too, so an empty + * @dst needs no special case. + */ +static void __init str_prepend(char *dst, size_t dst_len, + const char *src, size_t src_len) +{ + memmove(dst + src_len, dst, dst_len + 1); + memcpy(dst, src, src_len); +} + +/** + * xbc_prepend_embedded_cmdline() - Prepend embedded bootconfig cmdline + * @dst: cmdline buffer to prepend into (must already contain a NUL byte) + * @size: total capacity of @dst in bytes + * + * Prepend the build-time-rendered "kernel" subtree of the embedded + * bootconfig to @dst. The rendered string already ends with a single + * space (the xbc_snprint_cmdline() invariant), which serves as the + * separator between the embedded keys and any existing content of @dst. + * On overflow, log an error and leave @dst untouched rather than + * silently truncating: booting without the embedded values is better + * than refusing to boot, and the error message tells the user why + * their embedded keys are missing. + * + * Intended to be called from setup_arch() before parse_early_param() so + * that early_param() handlers see the embedded values. + */ +void __init xbc_prepend_embedded_cmdline(char *dst, size_t size) +{ + size_t embed_len = embedded_kernel_cmdline_end - embedded_kernel_cmdline; + size_t dst_len; + + if (!size || embed_len <= 1) /* trailing NUL only */ + return; + embed_len--; /* exclude trailing NUL byte */ + + dst_len = strnlen(dst, size); + if (embed_len + dst_len + 1 > size) { + pr_err("embedded bootconfig cmdline (%zu bytes) does not fit in COMMAND_LINE_SIZE with %zu bytes already used; ignoring embedded values\n", + embed_len, dst_len); + return; + } + + str_prepend(dst, dst_len, embedded_kernel_cmdline, embed_len); + xbc_cmdline_applied = true; +} + +/** + * xbc_embedded_cmdline_applied() - Did the embedded cmdline get prepended? + * + * Return true if xbc_prepend_embedded_cmdline() actually prepended the + * embedded "kernel" subtree. setup_boot_config() uses this to avoid + * rendering the same keys a second time. + */ +bool __init xbc_embedded_cmdline_applied(void) +{ + return xbc_cmdline_applied; +} +#endif /* CONFIG_CMDLINE_FROM_BOOTCONFIG */ + +/* parse_args() callback: flag when the "bootconfig" parameter is present. */ +static int __init bootconfig_optin(char *param, char *val, + const char *unused, void *arg) +{ + if (!strcmp(param, "bootconfig")) + *(bool *)arg = true; + return 0; +} + +/** + * bootconfig_cmdline_requested() - Was "bootconfig" passed on the cmdline? + * @boot_cmdline: kernel command line to inspect (not modified) + * @end_offset: if non-NULL, set to the offset of the init arguments that + * follow a "--" separator, or 0 when there is none + * + * Parse a private copy of @boot_cmdline (parse_args() is destructive) and + * report whether "bootconfig" is present before the "--" separator. + * setup_arch() uses this to gate prepending the build-time embedded cmdline; + * setup_boot_config() uses it for the runtime opt-in and to locate the init + * arguments via @end_offset. Sharing one parser keeps the early and late + * paths agreeing on what counts as opt-in. CONFIG_BOOT_CONFIG_FORCE is not + * folded in here; callers apply it where they need it. + */ +bool __init bootconfig_cmdline_requested(const char *boot_cmdline, int *end_offset) +{ + static char tmp_cmdline[COMMAND_LINE_SIZE] __initdata; + bool found = false; + char *err; + + if (end_offset) + *end_offset = 0; + + strscpy(tmp_cmdline, boot_cmdline, COMMAND_LINE_SIZE); + err = parse_args("bootconfig", tmp_cmdline, NULL, 0, 0, 0, + &found, bootconfig_optin); + if (IS_ERR(err)) + return false; + + /* parse_args() stops at "--" and returns the address of the rest. */ + if (end_offset && err) + *end_offset = err - tmp_cmdline; + + return found; +} + +#endif /* __KERNEL__ */ /* * Extra Boot Config (XBC) is given as tree-structured ascii text of @@ -64,14 +192,14 @@ static inline void __init xbc_free_mem(void *addr, size_t size, bool early) if (early) memblock_free(addr, size); else if (addr) - memblock_free_late(__pa(addr), size); + memblock_free(addr, size); } #else /* !__KERNEL__ */ static inline void *xbc_alloc_mem(size_t size) { - return malloc(size); + return calloc(1, size); } static inline void xbc_free_mem(void *addr, size_t size, bool early) @@ -79,6 +207,7 @@ static inline void xbc_free_mem(void *addr, size_t size, bool early) free(addr); } #endif + /** * xbc_get_info() - Get the information of loaded boot config * @node_size: A pointer to store the number of nodes. @@ -112,7 +241,7 @@ static int __init xbc_parse_error(const char *msg, const char *p) * xbc_root_node() - Get the root node of extended boot config * * Return the address of root node of extended boot config. If the - * extended boot config is not initiized, return NULL. + * extended boot config is not initialized, return NULL. */ struct xbc_node * __init xbc_root_node(void) { @@ -128,9 +257,9 @@ struct xbc_node * __init xbc_root_node(void) * * Return the index number of @node in XBC node list. */ -int __init xbc_node_index(struct xbc_node *node) +uint16_t __init xbc_node_index(struct xbc_node *node) { - return node - &xbc_nodes[0]; + return (uint16_t)(node - &xbc_nodes[0]); } /** @@ -180,7 +309,7 @@ struct xbc_node * __init xbc_node_get_next(struct xbc_node *node) */ const char * __init xbc_node_get_data(struct xbc_node *node) { - int offset = node->data & ~XBC_VALUE; + size_t offset = node->data & ~XBC_VALUE; if (WARN_ON(offset >= xbc_data_size)) return NULL; @@ -192,7 +321,7 @@ static bool __init xbc_node_match_prefix(struct xbc_node *node, const char **prefix) { const char *p = xbc_node_get_data(node); - int len = strlen(p); + size_t len = strlen(p); if (strncmp(*prefix, p, len)) return false; @@ -364,7 +493,7 @@ struct xbc_node * __init xbc_node_find_next_leaf(struct xbc_node *root, node = xbc_node_get_parent(node); if (node == root) return NULL; - /* User passed a node which is not uder parent */ + /* User passed a node which is not under parent */ if (WARN_ON(!node)) return NULL; } @@ -405,13 +534,89 @@ const char * __init xbc_node_find_next_key_value(struct xbc_node *root, return ""; /* No value key */ } +static char xbc_namebuf[XBC_KEYLEN_MAX] __initdata; + +#define rest(dst, end) ((end) > (dst) ? (end) - (dst) : 0) + +/** + * xbc_snprint_cmdline() - Render bootconfig keys under @root as a cmdline string + * @buf: Destination buffer (may be NULL when @size is 0 to query the length) + * @size: Size of @buf in bytes + * @root: Subtree root whose key=value pairs should be rendered + * + * Walk all key/value pairs under @root and emit them as a space-separated + * cmdline string into @buf. Values containing whitespace are quoted with + * double quotes. Returns the number of bytes that would be written if @buf + * were large enough (matching snprintf semantics), or a negative errno on + * failure. + */ +int __init xbc_snprint_cmdline(char *buf, size_t size, struct xbc_node *root) +{ + struct xbc_node *knode, *vnode; + const char *val, *q; + size_t len = 0; + int ret; + + /* + * Track the running written length rather than advancing @buf, so we + * never form "buf + size" or "buf += ret" while @buf is NULL (the + * size-probe call passes buf=NULL, size=0). NULL pointer arithmetic + * is undefined behavior and trips host UBSan / FORTIFY_SOURCE when + * this renderer runs at kernel build time. snprintf(NULL, 0, ...) + * itself is well defined and returns the would-be length. + */ + xbc_node_for_each_key_value(root, knode, val) { + /* + * An empty or value-only @root (e.g. "kernel {}" or + * "kernel = x", possibly alongside "kernel.foo = bar") + * yields @root itself here. Skip it: composing a key for it + * would fail with -EINVAL, yet any real descendant keys must + * still be rendered. An entirely empty subtree then renders + * nothing and returns 0 rather than an error. + */ + if (knode == root) + continue; + + ret = xbc_node_compose_key_after(root, knode, + xbc_namebuf, XBC_KEYLEN_MAX); + if (ret < 0) + return ret; + + vnode = xbc_node_get_child(knode); + if (!vnode) { + ret = snprintf(buf ? buf + len : NULL, rest(len, size), + "%s ", xbc_namebuf); + if (ret < 0) + return ret; + len += ret; + continue; + } + xbc_array_for_each_value(vnode, val) { + /* + * For prettier and more readable /proc/cmdline, only + * quote the value when necessary, i.e. when it contains + * whitespace. + */ + q = strpbrk(val, " \t\r\n") ? "\"" : ""; + ret = snprintf(buf ? buf + len : NULL, rest(len, size), + "%s=%s%s%s ", xbc_namebuf, q, val, q); + if (ret < 0) + return ret; + len += ret; + } + } + + return len; +} +#undef rest + /* XBC parse and tree build */ -static int __init xbc_init_node(struct xbc_node *node, char *data, uint32_t flag) +static int __init xbc_init_node(struct xbc_node *node, char *data, uint16_t flag) { - unsigned long offset = data - xbc_data; + long offset = data - xbc_data; - if (WARN_ON(offset >= XBC_DATA_MAX)) + if (WARN_ON(offset < 0 || offset >= XBC_DATA_MAX)) return -EINVAL; node->data = (uint16_t)offset | flag; @@ -421,16 +626,17 @@ static int __init xbc_init_node(struct xbc_node *node, char *data, uint32_t flag return 0; } -static struct xbc_node * __init xbc_add_node(char *data, uint32_t flag) +static struct xbc_node * __init xbc_add_node(char *data, uint16_t flag) { struct xbc_node *node; if (xbc_node_num == XBC_NODE_MAX) return NULL; - node = &xbc_nodes[xbc_node_num++]; + node = &xbc_nodes[xbc_node_num]; if (xbc_init_node(node, data, flag) < 0) return NULL; + xbc_node_num++; return node; } @@ -451,7 +657,7 @@ static inline __init struct xbc_node *xbc_last_child(struct xbc_node *node) return node; } -static struct xbc_node * __init __xbc_add_sibling(char *data, uint32_t flag, bool head) +static struct xbc_node * __init __xbc_add_sibling(char *data, uint16_t flag, bool head) { struct xbc_node *sib, *node = xbc_add_node(data, flag); @@ -472,23 +678,24 @@ static struct xbc_node * __init __xbc_add_sibling(char *data, uint32_t flag, boo sib->next = xbc_node_index(node); } } - } else + } else { xbc_parse_error("Too many nodes", data); + } return node; } -static inline struct xbc_node * __init xbc_add_sibling(char *data, uint32_t flag) +static inline struct xbc_node * __init xbc_add_sibling(char *data, uint16_t flag) { return __xbc_add_sibling(data, flag, false); } -static inline struct xbc_node * __init xbc_add_head_sibling(char *data, uint32_t flag) +static inline struct xbc_node * __init xbc_add_head_sibling(char *data, uint16_t flag) { return __xbc_add_sibling(data, flag, true); } -static inline __init struct xbc_node *xbc_add_child(char *data, uint32_t flag) +static inline __init struct xbc_node *xbc_add_child(char *data, uint16_t flag) { struct xbc_node *node = xbc_add_sibling(data, flag); @@ -655,9 +862,9 @@ static int __init __xbc_add_key(char *k) if (unlikely(xbc_node_num == 0)) goto add_node; - if (!last_parent) /* the first level */ + if (!last_parent) { /* the first level */ node = find_match_node(xbc_nodes, k); - else { + } else { child = xbc_node_get_child(last_parent); /* Since the value node is the first child, skip it. */ if (child && xbc_node_is_value(child)) @@ -665,9 +872,9 @@ static int __init __xbc_add_key(char *k) node = find_match_node(child, k); } - if (node) + if (node) { last_parent = node; - else { + } else { add_node: node = xbc_add_child(k, XBC_KEY); if (!node) @@ -798,7 +1005,8 @@ static int __init xbc_close_brace(char **k, char *n) static int __init xbc_verify_tree(void) { - int i, depth, len, wlen; + int i, depth; + size_t len, wlen; struct xbc_node *n, *m; /* Brace closing */ @@ -815,10 +1023,14 @@ static int __init xbc_verify_tree(void) } for (i = 0; i < xbc_node_num; i++) { - if (xbc_nodes[i].next > xbc_node_num) { + if (xbc_nodes[i].next >= xbc_node_num) { return xbc_parse_error("No closing brace", xbc_node_get_data(xbc_nodes + i)); } + if (xbc_nodes[i].child >= xbc_node_num) { + return xbc_parse_error("Broken child node", + xbc_node_get_data(xbc_nodes + i)); + } } /* Key tree limitation check */ @@ -980,7 +1192,6 @@ int __init xbc_init(const char *data, size_t size, const char **emsg, int *epos) _xbc_exit(true); return -ENOMEM; } - memset(xbc_nodes, 0, sizeof(struct xbc_node) * XBC_NODE_MAX); ret = xbc_parse_tree(); if (!ret) @@ -992,8 +1203,9 @@ int __init xbc_init(const char *data, size_t size, const char **emsg, int *epos) if (emsg) *emsg = xbc_err_msg; _xbc_exit(true); - } else + } else { ret = xbc_node_num; + } return ret; } |