{"record":{"id":"99d144531f56e84c","repo":"nodejs/node","slug":"ares-init-s","errorCode":null,"errorMessage":"ares_init: %s\n","messagePattern":"ares_init: (.+?)\n","errorType":"console","errorClass":null,"httpStatus":null,"severity":"error","filePath":"deps/cares/src/tools/ahost.c","lineNumber":148,"sourceCode":"      case '?':\n        print_help_info_ahost();\n        break;\n      default:\n        usage();\n        break;\n    }\n  }\n\n  argc -= state.optind;\n  argv += state.optind;\n  if (argc < 1) {\n    usage();\n  }\n\n  status = ares_init_options(&channel, &options, optmask);\n  if (status != ARES_SUCCESS) {\n    free(servers);\n    fprintf(stderr, \"ares_init: %s\\n\", ares_strerror(status));\n    return 1;\n  }\n\n  if (servers) {\n    status = ares_set_servers_csv(channel, servers);\n    if (status != ARES_SUCCESS) {\n      fprintf(stderr, \"ares_set_serveres_csv: %s\\n\", ares_strerror(status));\n      free(servers);\n      usage();\n      return 1;\n    }\n    free(servers);\n  }\n\n  /* Initiate the queries, one per command-line argument. */\n  for (; *argv; argv++) {\n    if (ares_inet_pton(AF_INET, *argv, &addr4) == 1) {\n      ares_gethostbyaddr(channel, &addr4, sizeof(addr4), AF_INET, callback,","sourceCodeStart":130,"sourceCodeEnd":166,"githubUrl":"https://github.com/nodejs/node/blob/1b2de5e052fc0fb95fd7fb6846dcec4ade598e9e/deps/cares/src/tools/ahost.c#L130-L166","documentation":"Printed by ahost's main() at ahost.c:148 when ares_init_options() fails to create the DNS channel. The function is called with &channel, &options, and optmask (accumulated from -D domain flags). The ares_strerror(status) detail is included. Before printing, the tool frees the servers string to avoid a leak. Returns 1.","triggerScenarios":"Calling ares_init_options() at line 146 after command-line parsing completes. Fails when the options struct and optmask are inconsistent — e.g., ARES_OPT_DOMAINS is set but options.domains contains malformed entries (from -D flags), or the system lacks resources to create internal sockets.","commonSituations":"A user passes malformed domain search list entries via -D. The system is out of file descriptors or memory for the channel's internal sockets. The optmask has bits set for options that were not properly initialized in the options struct.","solutions":["Check the ares_strerror() output for the specific status code.","Simplify: run ahost without -D flags to see if the domain list is the cause.","Validate domain names passed via -D — ensure they are syntactically valid DNS names.","Check system resource limits (ulimit -n) if the failure is resource-related."],"exampleFix":"// before: malformed domain causes init failure\nahost -D 'invalid..domain' example.com\n// -> 'ares_init: ...'\n\n// after: use valid domain\nahost -D 'example.com' example.com","handlingStrategy":"validation","validationCode":"// Validate domain search list entries before calling ares_init_options\nfor (int i = 0; i < options.ndomains; i++) {\n    if (options.domains[i] == NULL || options.domains[i][0] == '\\0') {\n        fprintf(stderr, \"empty domain at index %d\\n\", i);\n        return -1;\n    }\n}","typeGuard":null,"tryCatchPattern":"status = ares_init_options(&channel, &options, optmask);\nif (status != ARES_SUCCESS) {\n    fprintf(stderr, \"ares_init: %s\\n\", ares_strerror(status));\n    // retry with minimal options\n    optmask = 0;\n    memset(&options, 0, sizeof(options));\n    status = ares_init_options(&channel, &options, optmask);\n}","preventionTips":["Validate domain names passed via -D before running ahost.","Zero-initialize the ares_options struct before populating it.","Only set optmask bits for fields you have explicitly configured."],"tags":["c-ares","ahost","channel-init","configuration","ares-init"],"backgroundTag":null,"analyzedSha":"1b2de5e052fc0fb95fd7fb6846dcec4ade598e9e","analyzedAt":"2026-08-13T00:53:24.642Z","schemaVersion":2},"datasetVersion":"2026-08-13T04:17:16.726Z"}