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Diffstat (limited to 'lib/tar/number.c')
-rw-r--r--lib/tar/number.c94
1 files changed, 94 insertions, 0 deletions
diff --git a/lib/tar/number.c b/lib/tar/number.c
new file mode 100644
index 0000000..e85866d
--- /dev/null
+++ b/lib/tar/number.c
@@ -0,0 +1,94 @@
+/* SPDX-License-Identifier: GPL-3.0-or-later */
+#include "internal.h"
+
+int read_octal(const char *str, int digits, uint64_t *out)
+{
+ uint64_t result = 0;
+
+ while (digits > 0 && isspace(*str)) {
+ ++str;
+ --digits;
+ }
+
+ while (digits > 0 && *str >= '0' && *str <= '7') {
+ if (result > 0x1FFFFFFFFFFFFFFFUL) {
+ fputs("numeric overflow parsing tar header\n", stderr);
+ return -1;
+ }
+
+ result = (result << 3) | (*(str++) - '0');
+ --digits;
+ }
+
+ *out = result;
+ return 0;
+}
+
+int read_binary(const char *str, int digits, uint64_t *out)
+{
+ uint64_t x, ov, result = 0;
+ bool first = true;
+
+ while (digits > 0) {
+ x = *((const unsigned char *)str++);
+ --digits;
+
+ if (first) {
+ first = false;
+ if (x == 0xFF) {
+ result = 0xFFFFFFFFFFFFFFFFUL;
+ } else {
+ x &= 0x7F;
+ result = 0;
+ if (digits > 7 && x != 0)
+ goto fail_ov;
+ }
+ }
+
+ ov = (result >> 56) & 0xFF;
+
+ if (ov != 0 && ov != 0xFF)
+ goto fail_ov;
+
+ result = (result << 8) | x;
+ }
+
+ *out = result;
+ return 0;
+fail_ov:
+ fputs("numeric overflow parsing tar header\n", stderr);
+ return -1;
+}
+
+int read_number(const char *str, int digits, uint64_t *out)
+{
+ if (*((unsigned char *)str) & 0x80)
+ return read_binary(str, digits, out);
+
+ return read_octal(str, digits, out);
+}
+
+int pax_read_decimal(const char *str, uint64_t *out)
+{
+ uint64_t result = 0;
+
+ while (*str >= '0' && *str <= '9') {
+ if (result > 0xFFFFFFFFFFFFFFFFUL / 10) {
+ fputs("numeric overflow parsing pax header\n", stderr);
+ return -1;
+ }
+
+ result = (result * 10) + (*(str++) - '0');
+ }
+
+ *out = result;
+ return 0;
+}
+
+void write_octal(char *dst, unsigned int value, int digits)
+{
+ char temp[64];
+
+ sprintf(temp, "%0*o ", digits, value);
+ memcpy(dst, temp, strlen(temp));
+}