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-rw-r--r--util/libreboot-utils/lib/string.c636
1 files changed, 636 insertions, 0 deletions
diff --git a/util/libreboot-utils/lib/string.c b/util/libreboot-utils/lib/string.c
new file mode 100644
index 00000000..c083bd6d
--- /dev/null
+++ b/util/libreboot-utils/lib/string.c
@@ -0,0 +1,636 @@
+/* SPDX-License-Identifier: MIT
+ * Copyright (c) 2026 Leah Rowe <leah@libreboot.org>
+ *
+ * String functions
+ */
+
+#include <sys/types.h>
+#include <sys/stat.h>
+
+#include <errno.h>
+#include <stdarg.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <limits.h>
+#include <stdint.h>
+
+#include "../include/common.h"
+
+/* for null detection inside
+ * word-optimised string functions
+ */
+#define ff ((size_t)-1 / 0xFF)
+#define high ((ff) * 0x80)
+/* NOTE:
+ * do not assume that a match means
+ * both words have null at the same
+ * location. see how this is handled
+ * e.g. in scmp.
+ */
+#define zeroes(x) (((x) - (ff)) & ~(x) & (high))
+
+size_t
+page_remain(const void *p)
+{
+ /* calling sysconf repeatedly
+ * is folly. cache it (static)
+ */
+ static size_t pagesz = 0;
+ if (!pagesz)
+ pagesz = (size_t)pagesize();
+
+ return pagesz - ((uintptr_t)p & (pagesz - 1));
+}
+
+long
+pagesize(void)
+{
+ static long rval = 0;
+ static int set = 0;
+
+ if (!set) {
+ if ((rval = sysconf(_SC_PAGESIZE)) < 0)
+ err_exit(errno, "could not determine page size");
+ set = 1;
+ }
+
+ return rval;
+}
+
+void
+free_and_set_null(char **buf)
+{
+ if (buf == NULL)
+ err_exit(EFAULT,
+ "null ptr (to ptr for freeing) in free_and_set_null");
+
+ if (*buf == NULL)
+ return;
+
+ free(*buf);
+ *buf = NULL;
+}
+
+/* safe(ish) malloc.
+
+ use this and free_and_set_null()
+ in your program, to reduce the
+ chance of use after frees!
+
+ if you use these functions in the
+ intended way, you will greatly reduce
+ the number of bugs in your code
+ */
+char *
+smalloc(char **buf, size_t size)
+{
+ return (char *)vmalloc((void **)buf, size);
+}
+void *
+vmalloc(void **buf, size_t size)
+{
+ void *rval = NULL;
+
+ if (size >= SIZE_MAX - 1)
+ err_exit(EOVERFLOW, "integer overflow in vmalloc");
+ if (buf == NULL)
+ err_exit(EFAULT, "Bad pointer passed to vmalloc");
+
+ /* lots of programs will
+ * re-initialise a buffer
+ * that was allocated, without
+ * freeing or NULLing it. this
+ * is here intentionally, to
+ * force the programmer to behave
+ */
+ if (*buf != NULL)
+ err_exit(EFAULT, "Non-null pointer given to vmalloc");
+
+ if (!size)
+ err_exit(EFAULT,
+ "Tried to vmalloc(0) and that is very bad. Fix it now");
+
+ if ((rval = malloc(size)) == NULL)
+ err_exit(errno, "malloc fail in vmalloc");
+
+ return *buf = rval;
+}
+
+/* strict word-based strcmp */
+int
+scmp(const char *a,
+ const char *b,
+ size_t maxlen,
+ int *rval)
+{
+ size_t i = 0;
+ size_t j;
+ size_t wa;
+ size_t wb;
+ int saved_errno = errno;
+
+ if (if_err(a == NULL || b == NULL || rval == NULL, EFAULT))
+ goto err;
+
+ for ( ; ((uintptr_t)(a + i) % sizeof(size_t)) != 0; i++) {
+
+ if (if_err(i >= maxlen, EOVERFLOW))
+ goto err;
+ else if (!ccmp(a, b, i, rval))
+ goto out;
+ }
+
+ for ( ; i + sizeof(size_t) <= maxlen;
+ i += sizeof(size_t)) {
+
+ /* prevent crossing page boundary on word check */
+ if (page_remain(a + i) < sizeof(size_t) ||
+ page_remain(b + i) < sizeof(size_t))
+ break;
+
+ memcpy(&wa, a + i, sizeof(size_t));
+ memcpy(&wb, b + i, sizeof(size_t));
+
+ if (wa != wb)
+ for (j = 0; j < sizeof(size_t); j++)
+ if (!ccmp(a, b, i + j, rval))
+ goto out;
+
+ if (!zeroes(wa))
+ continue;
+
+ *rval = 0;
+ goto out;
+ }
+
+ for ( ; i < maxlen; i++)
+ if (!ccmp(a, b, i, rval))
+ goto out;
+
+err:
+ (void) set_errno(saved_errno, EFAULT);
+ if (rval != NULL)
+ *rval = -1;
+
+ err_exit(errno, "scmp");
+ return -1;
+out:
+ errno = saved_errno;
+ return *rval;
+}
+
+int ccmp(const char *a, const char *b,
+ size_t i, int *rval)
+{
+ unsigned char ac;
+ unsigned char bc;
+
+ if (if_err(a == NULL || b == NULL || rval == NULL, EFAULT))
+ err_exit(errno, "ccmp");
+
+ ac = (unsigned char)a[i];
+ bc = (unsigned char)b[i];
+
+ if (ac != bc) {
+ *rval = ac - bc;
+ return 0;
+ } else if (ac == '\0') {
+ *rval = 0;
+ return 0;
+ }
+
+ return 1;
+}
+
+/* strict word-based strlen */
+size_t
+slen(const char *s,
+ size_t maxlen,
+ size_t *rval)
+{
+ int saved_errno = errno;
+ size_t i = 0;
+ size_t w;
+ size_t j;
+
+ if (if_err(s == NULL || rval == NULL, EFAULT))
+ goto err;
+
+ for ( ; ((uintptr_t)(s + i) % sizeof(size_t)) != 0; i++) {
+
+ if (i >= maxlen)
+ goto err;
+ if (s[i] == '\0') {
+ *rval = i;
+ goto out;
+ }
+ }
+
+ for ( ; i + sizeof(size_t) <= maxlen;
+ i += sizeof(size_t)) {
+
+ memcpy(&w, s + i, sizeof(size_t));
+ if (!zeroes(w))
+ continue;
+
+ for (j = 0; j < sizeof(size_t); j++) {
+ if (s[i + j] == '\0') {
+ *rval = i + j;
+ goto out;
+ }
+ }
+ }
+
+ for ( ; i < maxlen; i++) {
+ if (s[i] == '\0') {
+ *rval = i;
+ goto out;
+ }
+ }
+
+err:
+ (void) set_errno(saved_errno, EFAULT);
+ if (rval != NULL)
+ *rval = 0;
+
+ err_exit(errno, "slen"); /* abort */
+ return 0; /* gcc15 is happy */
+out:
+ errno = saved_errno;
+ return *rval;
+}
+
+/* strict word-based strdup */
+char *
+sdup(const char *s,
+ size_t max, char **dest)
+{
+ size_t j;
+ size_t w;
+ size_t i = 0;
+ char *out = NULL;
+ int saved_errno = errno;
+
+ if (if_err(dest == NULL || *dest != NULL || s == NULL, EFAULT))
+ goto err;
+
+ out = smalloc(dest, max);
+
+ for ( ; ((uintptr_t)(s + i) % sizeof(size_t)) != 0; i++) {
+
+ if (if_err(i >= max, EOVERFLOW))
+ goto err;
+
+ out[i] = s[i];
+ if (s[i] == '\0') {
+ *dest = out;
+ goto out;
+ }
+ }
+
+ for ( ; i + sizeof(size_t) <= max; i += sizeof(size_t)) {
+
+ if (page_remain(s + i) < sizeof(size_t))
+ break;
+
+ memcpy(&w, s + i, sizeof(size_t));
+ if (!zeroes(w)) {
+ memcpy(out + i, &w, sizeof(size_t));
+ continue;
+ }
+
+ for (j = 0; j < sizeof(size_t); j++) {
+
+ out[i + j] = s[i + j];
+ if (s[i + j] == '\0') {
+ *dest = out;
+ goto out;
+ }
+ }
+ }
+
+ for ( ; i < max; i++) {
+
+ out[i] = s[i];
+ if (s[i] == '\0') {
+ *dest = out;
+ goto out;
+ }
+ }
+
+err:
+ free_and_set_null(&out);
+ if (dest != NULL)
+ *dest = NULL;
+
+ (void) set_errno(saved_errno, EFAULT);
+ err_exit(errno, "sdup");
+
+ return NULL;
+out:
+ errno = saved_errno;
+ return *dest;
+}
+
+/* concatenate N number of strings */
+char *
+scatn(ssize_t sc, const char **sv,
+ size_t max, char **rval)
+{
+ int saved_errno = errno;
+ char *final = NULL;
+ char *rcur = NULL;
+ char *rtmp = NULL;
+ size_t i;
+
+ if (if_err(sc < 2, EINVAL) ||
+ if_err(sv == NULL, EFAULT) ||
+ if_err(rval == NULL || *rval != NULL, EFAULT))
+ goto err;
+
+ for (i = 0; i < sc; i++) {
+
+ if (if_err(sv[i] == NULL, EFAULT))
+ goto err;
+ else if (i == 0) {
+ (void) sdup(sv[0], max, &final);
+ continue;
+ }
+
+ rtmp = NULL;
+ scat(final, sv[i], max, &rtmp);
+
+ free_and_set_null(&final);
+ final = rtmp;
+ rtmp = NULL;
+ }
+
+ errno = saved_errno;
+ *rval = final;
+ return *rval;
+err:
+ free_and_set_null(&rcur);
+ free_and_set_null(&rtmp);
+ free_and_set_null(&final);
+
+ (void) set_errno(saved_errno, EFAULT);
+
+ err_exit(errno, "scatn");
+ return NULL;
+}
+
+/* strict strcat */
+char *
+scat(const char *s1, const char *s2,
+ size_t n, char **dest)
+{
+ size_t size1;
+ size_t size2;
+ char *rval = NULL;
+ int saved_errno = errno;
+
+ if (if_err(dest == NULL || *dest != NULL, EFAULT))
+ goto err;
+
+ slen(s1, n, &size1);
+ slen(s2, n, &size2);
+
+ if (if_err(size1
+ > SIZE_MAX - size2 - 1, EOVERFLOW))
+ goto err;
+
+ smalloc(&rval, size1 + size2 + 1);
+
+ memcpy(rval, s1, size1);
+ memcpy(rval + size1, s2, size2);
+ *(rval + size1 + size2) = '\0';
+
+ *dest = rval;
+ errno = saved_errno;
+ return *dest;
+err:
+ (void) set_errno(saved_errno, EINVAL);
+ if (dest != NULL)
+ *dest = NULL;
+ err_exit(errno, "scat");
+
+ return NULL;
+}
+
+/* strict split/de-cat - off is where
+ 2nd buffer will start from */
+void
+dcat(const char *s, size_t n,
+ size_t off, char **dest1,
+ char **dest2)
+{
+ size_t size;
+ char *rval1 = NULL;
+ char *rval2 = NULL;
+ int saved_errno = errno;
+
+ if (if_err(dest1 == NULL || dest2 == NULL, EFAULT))
+ goto err;
+
+ if (if_err(slen(s, n, &size) >= SIZE_MAX - 1, EOVERFLOW) ||
+ if_err(off >= size, EOVERFLOW))
+ goto err;
+
+ memcpy(smalloc(&rval1, off + 1),
+ s, off);
+ *(rval1 + off) = '\0';
+
+ memcpy(smalloc(&rval2, size - off +1),
+ s + off, size - off);
+ *(rval2 + size - off) = '\0';
+
+ *dest1 = rval1;
+ *dest2 = rval2;
+
+ errno = saved_errno;
+ return;
+
+err:
+ *dest1 = *dest2 = NULL;
+
+ free_and_set_null(&rval1);
+ free_and_set_null(&rval2);
+
+ (void) set_errno(saved_errno, EINVAL);
+ err_exit(errno, "dcat");
+}
+
+/* because no libc reimagination is complete
+ * without a reimplementation of memcmp. and
+ * no safe one is complete without null checks.
+ */
+int
+vcmp(const void *s1, const void *s2, size_t n)
+{
+ int saved_errno = errno;
+ size_t i = 0;
+ size_t a;
+ size_t b;
+
+ const unsigned char *x;
+ const unsigned char *y;
+
+ if (if_err(s1 == NULL || s2 == NULL, EFAULT))
+ err_exit(EFAULT, "vcmp: null input");
+
+ x = s1;
+ y = s2;
+
+ for ( ; i + sizeof(size_t) <= n; i += sizeof(size_t)) {
+
+ memcpy(&a, x + i, sizeof(size_t));
+ memcpy(&b, y + i, sizeof(size_t));
+
+ if (a != b)
+ break;
+ }
+
+ for ( ; i < n; i++)
+ if (x[i] != y[i])
+ return (int)x[i] - (int)y[i];
+
+ errno = saved_errno;
+ return 0;
+}
+
+/* on functions that return with errno,
+ * i sometimes have a default fallback,
+ * which is set if errno wasn't changed,
+ * under error condition.
+ */
+int
+set_errno(int saved_errno, int fallback)
+{
+ if (errno == saved_errno)
+ errno = fallback;
+ return -1;
+}
+
+/* the one for nvmutil state is in state.c */
+/* this one just exits */
+void
+err_exit(int nvm_errval, const char *msg, ...)
+{
+ va_list args;
+ int saved_errno = errno;
+ const char *p;
+
+ func_t err_cleanup = errhook(NULL);
+ err_cleanup();
+ errno = saved_errno;
+
+ if (!errno)
+ saved_errno = errno = ECANCELED;
+
+ fprintf(stderr, "%s: ", lbgetprogname());
+
+ va_start(args, msg);
+ vfprintf(stderr, msg, args);
+ va_end(args);
+
+ fprintf(stderr, ": %s\n", strerror(errno));
+
+ exit(EXIT_FAILURE);
+}
+
+/* the err function will
+ * call this upon exit, and
+ * cleanup will be performed
+ * e.g. you might want to
+ * close some files, depending
+ * on your program.
+ * see: err_exit()
+ */
+func_t errhook(func_t ptr)
+{
+ static int set = 0;
+ static func_t hook = NULL;
+
+ if (!set) {
+ set = 1;
+
+ if (ptr == NULL)
+ hook = no_op;
+ else
+ hook = ptr;
+ }
+
+ return hook;
+}
+
+void
+no_op(void)
+{
+ return;
+}
+
+const char *
+lbgetprogname(void)
+{
+ char *name = lbsetprogname(NULL);
+ char *p = NULL;
+ if (name)
+ p = strrchr(name, '/');
+ if (p)
+ return p + 1;
+ else if (name)
+ return name;
+ else
+ return "libreboot-utils";
+}
+
+/* singleton. if string not null,
+ sets the string. after set,
+ will not set anymore. either
+ way, returns the string
+ */
+char *
+lbsetprogname(char *argv0)
+{
+ static char *progname = NULL;
+ static int set = 0;
+
+ if (!set) {
+ if (argv0 == NULL)
+ return "libreboot-utils";
+ (void) sdup(argv0, 4096, &progname);
+ set = 1;
+ }
+
+ return progname;
+}
+
+/* https://man.openbsd.org/pledge.2
+ https://man.openbsd.org/unveil.2 */
+int
+xpledgex(const char *promises, const char *execpromises)
+{
+ int saved_errno = errno;
+ (void) promises, (void) execpromises, (void) saved_errno;
+#ifdef __OpenBSD__
+ if (pledge(promises, execpromises) == -1)
+ err_exit(errno, "pledge");
+#endif
+ errno = saved_errno;
+ return 0;
+}
+int
+xunveilx(const char *path, const char *permissions)
+{
+ int saved_errno = errno;
+ (void) path, (void) permissions, (void) saved_errno;
+#ifdef __OpenBSD__
+ if (pledge(promises, execpromises) == -1)
+ err_exit(errno, "pledge");
+#endif
+ errno = saved_errno;
+ return 0;
+}
generated by cgit v1.2.1 (git 2.18.0) at 2026-03-30 12:02:26 +0000