wasi-libc

History

Henri Nurmi 1b19fc65ad getaddrinfo: improve the service/port resolution (#524 ) Hello, While experimenting with the `wasm32-wasip2` target and CPython, I discovered an issue with the `getaddrinfo()` implementation: it fails to resolve the provided service into a port number, causing `sin_port` to always be set to 0. This issue leads to failures in network-related functions that rely on `getaddrinfo()`, such as Python's `urllib3` library, which passes the result directly to `connect()`. This results in connection attempts using a port value of 0, which naturally fails. ### Minimal example to reproduce the problem ```c #include <arpa/inet.h> #include <netdb.h> #include <stdio.h> int main(void) { struct addrinfo res = NULL; getaddrinfo("google.com", "443", NULL, &res); for (struct addrinfo i = res; i != NULL; i = i->ai_next) { char str[INET6_ADDRSTRLEN]; if (i->ai_addr->sa_family == AF_INET) { struct sockaddr_in p = (struct sockaddr_in )i->ai_addr; int port = ntohs(p->sin_port); printf("%s: %i\n", inet_ntop(AF_INET, &p->sin_addr, str, sizeof(str)), port); } else if (i->ai_addr->sa_family == AF_INET6) { struct sockaddr_in6 p = (struct sockaddr_in6 )i->ai_addr; int port = ntohs(p->sin6_port); printf("%s: %i\n", inet_ntop(AF_INET6, &p->sin6_addr, str, sizeof(str)), port); } } return 0; } ``` ``` $ /opt/wasi-sdk/bin/clang -target wasm32-wasip2 -o foo foo.c $ wasmtime run -S allow-ip-name-lookup=y foo 216.58.211.238: 0 2a00:1450:4026:808::200e: 0 ``` Expected output: ``` 216.58.211.238: 443 2a00:1450:4026:808::200e: 443 ``` ### Root Cause The root cause is that `getaddrinfo()` does not correctly translate the provided service into a port number. As described in the `getaddrinfo()` man [page](https://man7.org/linux/man-pages/man3/getaddrinfo.3.html), the function should: > service sets the port in each returned address structure. If this argument is a service name (see [services(5)](https://man7.org/linux/man-pages/man5/services.5.html)), it is translated to the corresponding port number. This argument can also be specified as a decimal number, which is simply converted to binary. If service is NULL, then the port number of the returned socket addresses will be left uninitialized. ### Proposed Fix This pull request addresses the issue by implementing the following behavior for `getaddrinfo()`: * If the service is `NULL`, the port number in the returned socket addresses remains uninitialized. * The value is converted to an integer and validated if the service is numeric. The PR does not currently add support for translating named services into port numbers because `getservbyname()` has not been implemented. In cases where a named service is provided, the `EAI_NONAME` error code is returned.		2 months ago
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math	Merge the basics component into libc-bottom-half. (#199)	4 years ago
__errno_location.c	Define an `__errno_location` function. (#347)	2 years ago
__main_void.c	add shared library support (#429)	1 year ago
__wasilibc_dt.c	Add implementation file.	3 years ago
__wasilibc_environ.c	Also add a way to read `environ` without triggering eager init.	4 years ago
__wasilibc_fd_renumber.c	wasip2 support for `close`, `poll`, `pselect` (#486)	7 months ago
__wasilibc_initialize_environ.c	Move `weak` attribute to front (#310)	2 years ago
__wasilibc_real.c	Rename thread_spawn import (#387)	2 years ago
__wasilibc_rmdirat.c	Fix missing errno assignments.	2 years ago
__wasilibc_tell.c	Wasi snapshot preview1 (#140)	5 years ago
__wasilibc_unlinkat.c	Delete several blocks of unused code. (#294)	2 years ago
abort.c	Merge the basics component into libc-bottom-half. (#199)	4 years ago
accept-wasip1.c	implement basic TCP/UDP server support (#481)	8 months ago
accept-wasip2.c	implement basic TCP/UDP server support (#481)	8 months ago
at_fdcwd.c	AT_FDCWD support.	4 years ago
bind.c	implement basic TCP/UDP server support (#481)	8 months ago
chdir.c	Fix `make THREAD_MODEL=posix` (#311)	2 years ago
complex-builtins.c	Implement the cimag/creal functions for all types consistently.	4 years ago
connect.c	implement basic TCP/UDP client support (#477)	8 months ago
descriptor_table.c	implement basic TCP/UDP client support (#477)	8 months ago
environ.c	Use MUSL's `weak*` feature in bottom half (#306)	2 years ago
errno.c	Merge the basics component into libc-bottom-half. (#199)	4 years ago
getcwd.c	Fix `make THREAD_MODEL=posix` (#311)	2 years ago
getentropy.c	Fix `make THREAD_MODEL=posix` (#311)	2 years ago
getsockpeername.c	implement `getsockname`, `getpeername`, and `getaddrinfo` (#488)	7 months ago
isatty.c	Wasi snapshot preview1 (#140)	5 years ago
listen.c	implement basic TCP/UDP server support (#481)	8 months ago
netdb.c	getaddrinfo: improve the service/port resolution (#524)	2 months ago
poll-wasip2.c	wasip2 support for `close`, `poll`, `pselect` (#486)	7 months ago
posix.c	add stubs for `statvfs`, `chmod`, etc. (#463)	10 months ago
preopens.c	Remove extra lock-taking in preopen setup (#491)	6 months ago
reallocarray.c	Merge the basics component into libc-bottom-half. (#199)	4 years ago
recv.c	implement basic TCP/UDP client support (#477)	8 months ago
sbrk.c	Use consistent style for wasi-libc C source files. (#131)	5 years ago
send.c	implement basic TCP/UDP client support (#477)	8 months ago
shutdown.c	add wasip2 implementations of more socket APIs (#482)	8 months ago
socket.c	implement basic TCP/UDP client support (#477)	8 months ago
sockets_utils.c	getaddrinfo: improve the service/port resolution (#524)	2 months ago
sockopt.c	add wasip2 implementations of more socket APIs (#482)	8 months ago
truncate.c	Avoid varargs conventions when calling open (#126)	5 years ago
wasip2.c	Start renaming preview1 to p1 and preview2 to p2 (#478)	8 months ago
wasip2_component_type.o	Start renaming preview1 to p1 and preview2 to p2 (#478)	8 months ago