/* 9p/defs.c - TODO * * Copyright (C) 2024 Luke T. Shumaker * SPDX-Licence-Identifier: AGPL-3.0-or-later */ #include /* for PRIu{n} */ #include /* for va_* */ #include /* for vsnprintf() */ #include /* for strncpy() */ #include "9p/defs.h" #include "9p/linux-errno.h" #include "9p/internal.h" static struct version *versions[_P9_VER_CNT] = { [P9_VER_9P2000] = &version_9P2000, /* [P9_VER_9P2000u] = &version_9P2000u, */ }; int p9_error(struct p9_ctx *ctx, uint32_t linux_errno, char const *msg) { strncpy(ctx->err_msg, msg, sizeof(ctx->err_msg)); ctx->err_msg[sizeof(ctx->err_msg)-1] = '\0'; ctx->err_num = linux_errno; return -1; } int p9_errorf(struct p9_ctx *ctx, uint32_t linux_errno, char const *fmt, ...) { int n; va_list args; va_start(args, fmt); n = vsnprintf(ctx->err_msg, sizeof(ctx->err_msg), fmt, args); va_end(args); if ((size_t)(n+1) < sizeof(ctx->err_msg)) memset(&ctx->err_msg[n+1], 0, sizeof(ctx->err_msg)-(n+1)); ctx->err_num = linux_errno; return -1; } size_t p9_unmarshal_size(struct p9_ctx *ctx, uint8_t *net_bytes) { /* Header */ uint32_t net_len = decode_u32le(net_bytes); if (net_len < 7) return p9_error(ctx, LINUX_EBADMSG, "message is too short"); uint8_t typ = net_bytes[4]; uint32_t net_offset = 7; /* Body */ if (!versions[ctx->version]->msgs[typ].unmarshal_extrasize) return p9_errorf(ctx, LINUX_EOPNOTSUPP, "unknown message type %"PRIu8, typ); size_t host_size = versions[ctx->version]->msgs[typ].unmarshal_basesize; if (versions[ctx->version]->msgs[typ].unmarshal_extrasize(net_len, net_bytes, &net_offset, &host_size)) return p9_error(ctx, LINUX_EBADMSG, "message is too short for content"); return host_size; } uint8_t p9_unmarshal(struct p9_ctx *ctx, uint8_t *net_bytes, uint16_t *out_tag, void *out_body) { /* Header */ uint8_t typ = net_bytes[4]; *out_tag = decode_u16le(&net_bytes[5]); uint32_t net_offset = 7; /* Body */ void *host_extra = out_body + versions[ctx->version]->msgs[typ].unmarshal_basesize; if (versions[ctx->version]->msgs[typ].unmarshal(net_bytes, &net_offset, &host_extra, out_body)) return p9_error(ctx, LINUX_EBADMSG, "message contains invalid UTF-8"); return typ; } uint32_t _p9_marshal(struct p9_ctx *ctx, uint8_t typ, uint16_t msgid, void *body, uint8_t *out_bytes) { /* Header */ out_bytes[4] = typ; encode_u16le(msgid, &out_bytes[5]); uint32_t net_offset = 7; /* Body */ if (versions[ctx->version]->msgs[typ].marshal(ctx, body, out_bytes, &net_offset)) return 0; /* Header, again */ encode_u32le(net_offset, out_bytes); return net_offset; }