// Copyright (c) Meta Platforms, Inc. and affiliates.
// SPDX-License-Identifier: LGPL-2.1-or-later

static struct drgn_error *parse_vmcoreinfo_u64(const char *value,
					       const char *newline, int base,
					       uint64_t *ret)
{
	errno = 0;
	char *end;
	*ret = strtoull(value, &end, base);
	if (errno == ERANGE) {
		return drgn_error_create(DRGN_ERROR_OVERFLOW,
					 "number in VMCOREINFO is too large");
	} else if (errno || end == value || end != newline) {
		return drgn_error_create(DRGN_ERROR_OTHER,
					 "number in VMCOREINFO is invalid");
	}
	return NULL;
}

struct drgn_error *drgn_program_parse_vmcoreinfo(struct drgn_program *prog,
						 const char *desc,
						 size_t descsz)
{
	struct drgn_error *err;

	prog->vmcoreinfo.raw_size = descsz;
	prog->vmcoreinfo.raw = memdup(desc, descsz);
	if (!prog->vmcoreinfo.raw)
		return &drgn_enomem;
	for (const char *line = desc, *end = &desc[descsz], *newline;
	     (newline = memchr(line, '\n', end - line));
	     line = newline + 1) {
		const char *equals = memchr(line, '=', newline - line);
		if (!equals)
			continue;

		const char *value = equals + 1;
		@memswitch (line, equals - line)@
		@case "OSRELEASE"@
			if ((size_t)(newline - value) >=
			    sizeof(prog->vmcoreinfo.osrelease)) {
				return drgn_error_create(DRGN_ERROR_OTHER,
							 "OSRELEASE in VMCOREINFO is too long");
			}
			memcpy(prog->vmcoreinfo.osrelease, value,
			       newline - value);
			prog->vmcoreinfo.osrelease[newline - value] = '\0';
			break;
		@case "PAGESIZE"@
			err = parse_vmcoreinfo_u64(value, newline, 0,
						   &prog->vmcoreinfo.page_size);
			if (err)
				return err;
			break;
		@case "KERNELOFFSET"@
			err = parse_vmcoreinfo_u64(value, newline, 16,
						   &prog->vmcoreinfo.kaslr_offset);
			if (err)
				return err;
			break;
		@case "SYMBOL(swapper_pg_dir)"@
			err = parse_vmcoreinfo_u64(value, newline, 16,
						   &prog->vmcoreinfo.swapper_pg_dir);
			if (err)
				return err;
			break;
		@case "LENGTH(mem_section)"@
			err = parse_vmcoreinfo_u64(value, newline, 0,
						   &prog->vmcoreinfo.mem_section_length);
			if (err)
				return err;
			break;
		@case "NUMBER(pgtable_l5_enabled)"@
		{
			uint64_t tmp;
			err = parse_vmcoreinfo_u64(value, newline, 0, &tmp);
			if (err)
				return err;
			prog->vmcoreinfo.pgtable_l5_enabled = tmp;
			break;
		}
		@case "NUMBER(phys_base)"@
		{
			err = parse_vmcoreinfo_u64(value, newline, 0,
						   &prog->vmcoreinfo.phys_base);;
			if (err)
				return err;
			break;
		}
		@case "NUMBER(KERNELPACMASK)"@
			err = parse_vmcoreinfo_u64(value, newline, 16,
						   &prog->aarch64_insn_pac_mask);
			if (err)
				return err;
			break;
		@case "NUMBER(VA_BITS)"@
			err = parse_vmcoreinfo_u64(value, newline, 0,
						   &prog->vmcoreinfo.va_bits);
			if (err)
				return err;
			break;
		@endswitch@
	}
	if (!prog->vmcoreinfo.osrelease[0]) {
		return drgn_error_create(DRGN_ERROR_OTHER,
					 "VMCOREINFO does not contain valid OSRELEASE");
	}
	if (!is_power_of_two(prog->vmcoreinfo.page_size)) {
		return drgn_error_create(DRGN_ERROR_OTHER,
					 "VMCOREINFO does not contain valid PAGESIZE");
	}
	prog->vmcoreinfo.page_shift = ctz(prog->vmcoreinfo.page_size);
	if (!prog->vmcoreinfo.swapper_pg_dir) {
		return drgn_error_create(DRGN_ERROR_OTHER,
					 "VMCOREINFO does not contain valid swapper_pg_dir");
	}
	// Everything else is optional.
	return NULL;
}