/*++ /* NAME /* qmgr_feedback 3 /* SUMMARY /* delivery agent feedback management /* SYNOPSIS /* #include "qmgr.h" /* /* void qmgr_feedback_init(fbck_ctl, name_prefix, name_tail, /* def_name, def_value) /* QMGR_FEEDBACK *fbck_ctl; /* const char *name_prefix; /* const char *name_tail; /* const char *def_name; /* const char *def_value; /* /* double QMGR_FEEDBACK_VAL(fbck_ctl, concurrency) /* QMGR_FEEDBACK *fbck_ctl; /* const int concurrency; /* DESCRIPTION /* Upon completion of a delivery request, a delivery agent /* provides a hint that the scheduler should dedicate fewer or /* more resources to a specific destination. /* /* qmgr_feedback_init() looks up transport-dependent positive /* or negative concurrency feedback control information from /* main.cf, and converts it to internal form. /* /* QMGR_FEEDBACK_VAL() computes a concurrency adjustment based /* on a preprocessed feedback control information and the /* current concurrency window. This is an "unsafe" macro that /* evaluates some arguments multiple times. /* /* Arguments: /* .IP fbck_ctl /* Pointer to QMGR_FEEDBACK structure where the result will /* be stored. /* .IP name_prefix /* Mail delivery transport name, used as the initial portion /* of a transport-dependent concurrency feedback parameter /* name. /* .IP name_tail /* The second, and fixed, portion of a transport-dependent /* concurrency feedback parameter. /* .IP def_name /* The name of a default feedback parameter. /* .IP def_val /* The value of the default feedback parameter. /* .IP concurrency /* Delivery concurrency for concurrency-dependent feedback calculation. /* DIAGNOSTICS /* Warning: configuration error or unreasonable input. The program /* uses name_tail feedback instead. /* Panic: consistency check failure. /* LICENSE /* .ad /* .fi /* The Secure Mailer license must be distributed with this software. /* AUTHOR(S) /* Wietse Venema /* IBM T.J. Watson Research /* P.O. Box 704 /* Yorktown Heights, NY 10598, USA /*--*/ /* System library. */ #include <sys_defs.h> #include <stdlib.h> #include <limits.h> /* INT_MAX */ #include <stdio.h> /* sscanf() */ #include <string.h> /* Utility library. */ #include <msg.h> #include <name_code.h> #include <stringops.h> #include <mymalloc.h> /* Global library. */ #include <mail_params.h> #include <mail_conf.h> /* Application-specific. */ #include "qmgr.h" /* * Lookup tables for main.cf feedback method names. */ const NAME_CODE qmgr_feedback_map[] = { CONC_FDBACK_NAME_WIN, QMGR_FEEDBACK_IDX_WIN, #ifdef QMGR_FEEDBACK_IDX_SQRT_WIN CONC_FDBACK_NAME_SQRT_WIN, QMGR_FEEDBACK_IDX_SQRT_WIN, #endif 0, QMGR_FEEDBACK_IDX_NONE, }; /* qmgr_feedback_init - initialize feedback control */ void qmgr_feedback_init(QMGR_FEEDBACK *fb, const char *name_prefix, const char *name_tail, const char *def_name, const char *def_val) { double enum_val; char denom_str[30 + 1]; double denom_val; char slash; char junk; char *fbck_name; char *fbck_val; /* * Look up the transport-dependent feedback value. */ fbck_name = concatenate(name_prefix, name_tail, (char *) 0); fbck_val = get_mail_conf_str(fbck_name, def_val, 1, 0); /* * We allow users to express feedback as 1/8, as a more user-friendly * alternative to 0.125 (or worse, having users specify the number of * events in a feedback hysteresis cycle). * * We use some sscanf() fu to parse the value into numerator and optional * "/" followed by denominator. We're doing this only a few times during * the process life time, so we strive for convenience instead of speed. */ #define INCLUSIVE_BOUNDS(val, low, high) ((val) >= (low) && (val) <= (high)) fb->hysteresis = 1; /* legacy */ fb->base = -1; /* assume error */ switch (sscanf(fbck_val, "%lf %1[/] %30s%c", &enum_val, &slash, denom_str, &junk)) { case 1: fb->index = QMGR_FEEDBACK_IDX_NONE; fb->base = enum_val; break; case 3: if ((fb->index = name_code(qmgr_feedback_map, NAME_CODE_FLAG_NONE, denom_str)) != QMGR_FEEDBACK_IDX_NONE) { fb->base = enum_val; } else if (INCLUSIVE_BOUNDS(enum_val, 0, INT_MAX) && sscanf(denom_str, "%lf%c", &denom_val, &junk) == 1 && INCLUSIVE_BOUNDS(denom_val, 1.0 / INT_MAX, INT_MAX)) { fb->base = enum_val / denom_val; } break; } /* * Sanity check. If input is bad, we just warn and use a reasonable * default. */ if (!INCLUSIVE_BOUNDS(fb->base, 0, 1)) { msg_warn("%s: ignoring malformed or unreasonable feedback: %s", strcmp(fbck_val, def_val) ? fbck_name : def_name, fbck_val); fb->index = QMGR_FEEDBACK_IDX_NONE; fb->base = 1; } /* * Performance debugging/analysis. */ if (var_conc_feedback_debug) msg_info("%s: %s feedback type %d value at %d: %g", name_prefix, strcmp(fbck_val, def_val) ? fbck_name : def_name, fb->index, var_init_dest_concurrency, QMGR_FEEDBACK_VAL(*fb, var_init_dest_concurrency)); myfree(fbck_name); myfree(fbck_val); }