diff options
Diffstat (limited to 'src/qmgr/qmgr_feedback.c')
| -rw-r--r-- | src/qmgr/qmgr_feedback.c | 177 |
1 files changed, 177 insertions, 0 deletions
diff --git a/src/qmgr/qmgr_feedback.c b/src/qmgr/qmgr_feedback.c new file mode 100644 index 0000000..bf7aebb --- /dev/null +++ b/src/qmgr/qmgr_feedback.c @@ -0,0 +1,177 @@ +/*++ +/* 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[1 + 1]; + 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); +} |