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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 16:18:56 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 16:18:56 +0000 |
commit | b7c15c31519dc44c1f691e0466badd556ffe9423 (patch) | |
tree | f944572f288bab482a615e09af627d9a2b6727d8 /src/cleanup/cleanup_region.c | |
parent | Initial commit. (diff) | |
download | postfix-upstream.tar.xz postfix-upstream.zip |
Adding upstream version 3.7.10.upstream/3.7.10upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r-- | src/cleanup/cleanup_region.c | 232 |
1 files changed, 232 insertions, 0 deletions
diff --git a/src/cleanup/cleanup_region.c b/src/cleanup/cleanup_region.c new file mode 100644 index 0000000..b2acbee --- /dev/null +++ b/src/cleanup/cleanup_region.c @@ -0,0 +1,232 @@ +/*++ +/* NAME +/* cleanup_region 3 +/* SUMMARY +/* queue file region manager +/* SYNOPSIS +/* #include "cleanup.h" +/* +/* void cleanup_region_init(state) +/* CLEANUP_STATE *state; +/* +/* CLEANUP_REGION *cleanup_region_open(state, space_needed) +/* CLEANUP_STATE *state; +/* ssize_t space_needed; +/* +/* int cleanup_region_close(state, rp) +/* CLEANUP_STATE *state; +/* CLEANUP_REGION *rp; +/* +/* CLEANUP_REGION *cleanup_region_return(state, rp) +/* CLEANUP_STATE *state; +/* CLEANUP_REGION *rp; +/* +/* void cleanup_region_done(state) +/* CLEANUP_STATE *state; +/* DESCRIPTION +/* This module maintains queue file regions. Regions are created +/* on-the-fly and can be reused multiple times. Each region +/* structure consists of a file offset, a length (0 for an +/* open-ended region at the end of the file), a write offset +/* (maintained by the caller), and list linkage. Region +/* boundaries are not enforced by this module. It is up to the +/* caller to ensure that they stay within bounds. +/* +/* cleanup_region_init() performs mandatory initialization and +/* overlays an initial region structure over an already existing +/* queue file. This function must not be called before the +/* queue file is complete. +/* +/* cleanup_region_open() opens an existing region or creates +/* a new region that can accommodate at least the specified +/* amount of space. A new region is an open-ended region at +/* the end of the file; it must be closed (see next) before +/* unrelated data can be appended to the same file. +/* +/* cleanup_region_close() indicates that a region will not be +/* updated further. With an open-ended region, the region's +/* end is frozen just before the caller-maintained write offset. +/* With a close-ended region, unused space (beginning at the +/* caller-maintained write offset) may be returned to the free +/* pool. +/* +/* cleanup_region_return() returns a list of regions to the +/* free pool, and returns a null pointer. To avoid fragmentation, +/* adjacent free regions may be coalesced together. +/* +/* cleanup_region_done() destroys all in-memory information +/* that was allocated for administering queue file regions. +/* +/* Arguments: +/* .IP state +/* Queue file and message processing state. This state is +/* updated as records are processed and as errors happen. +/* .IP space_needed +/* The minimum region size needed. +/* 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 <sys/stat.h> + +/* Utility library. */ + +#include <msg.h> +#include <mymalloc.h> +#include <warn_stat.h> + +/* Application-specific. */ + +#include <cleanup.h> + +/* cleanup_region_alloc - create queue file region */ + +static CLEANUP_REGION *cleanup_region_alloc(off_t start, off_t len) +{ + CLEANUP_REGION *rp; + + rp = (CLEANUP_REGION *) mymalloc(sizeof(*rp)); + rp->write_offs = rp->start = start; + rp->len = len; + rp->next = 0; + + return (rp); +} + +/* cleanup_region_free - destroy region list */ + +static CLEANUP_REGION *cleanup_region_free(CLEANUP_REGION *regions) +{ + CLEANUP_REGION *rp; + CLEANUP_REGION *next; + + for (rp = regions; rp != 0; rp = next) { + next = rp->next; + myfree((void *) rp); + } + return (0); +} + +/* cleanup_region_init - create initial region overlay */ + +void cleanup_region_init(CLEANUP_STATE *state) +{ + const char *myname = "cleanup_region_init"; + + /* + * Sanity check. + */ + if (state->free_regions != 0 || state->body_regions != 0) + msg_panic("%s: repeated call", myname); + + /* + * Craft the first regions on the fly, from circumstantial evidence. + */ + state->body_regions = + cleanup_region_alloc(state->append_hdr_pt_target, + state->xtra_offset - state->append_hdr_pt_target); + if (msg_verbose) + msg_info("%s: body start %ld len %ld", + myname, (long) state->body_regions->start, (long) state->body_regions->len); +} + +/* cleanup_region_open - open existing region or create new region */ + +CLEANUP_REGION *cleanup_region_open(CLEANUP_STATE *state, ssize_t len) +{ + const char *myname = "cleanup_region_open"; + CLEANUP_REGION **rpp; + CLEANUP_REGION *rp; + struct stat st; + + /* + * Find the first region that is large enough, or create a new region. + */ + for (rpp = &state->free_regions; /* see below */ ; rpp = &(rp->next)) { + + /* + * Create an open-ended region at the end of the queue file. We + * freeze the region size after we stop writing to it. XXX Assume + * that fstat() returns a file size that is never less than the file + * append offset. It is not a problem if fstat() returns a larger + * result; we would just waste some space. + */ + if ((rp = *rpp) == 0) { + if (fstat(vstream_fileno(state->dst), &st) < 0) + msg_fatal("%s: fstat file %s: %m", myname, cleanup_path); + rp = cleanup_region_alloc(st.st_size, 0); + break; + } + + /* + * Reuse an existing region. + */ + if (rp->len >= len) { + (*rpp) = rp->next; + rp->next = 0; + rp->write_offs = rp->start; + break; + } + + /* + * Skip a too small region. + */ + if (msg_verbose) + msg_info("%s: skip start %ld len %ld < %ld", + myname, (long) rp->start, (long) rp->len, (long) len); + } + if (msg_verbose) + msg_info("%s: done start %ld len %ld", + myname, (long) rp->start, (long) rp->len); + return (rp); +} + +/* cleanup_region_close - freeze queue file region size */ + +void cleanup_region_close(CLEANUP_STATE *unused_state, CLEANUP_REGION *rp) +{ + const char *myname = "cleanup_region_close"; + + /* + * If this region is still open ended, freeze the size. If this region is + * closed, some future version of this routine may shrink the size and + * return the unused portion to the free pool. + */ + if (rp->len == 0) + rp->len = rp->write_offs - rp->start; + if (msg_verbose) + msg_info("%s: freeze start %ld len %ld", + myname, (long) rp->start, (long) rp->len); +} + +/* cleanup_region_return - return region list to free pool */ + +CLEANUP_REGION *cleanup_region_return(CLEANUP_STATE *state, CLEANUP_REGION *rp) +{ + CLEANUP_REGION **rpp; + + for (rpp = &state->free_regions; (*rpp) != 0; rpp = &(*rpp)->next) + /* void */ ; + *rpp = rp; + return (0); +} + +/* cleanup_region_done - destroy region metadata */ + +void cleanup_region_done(CLEANUP_STATE *state) +{ + if (state->free_regions != 0) + state->free_regions = cleanup_region_free(state->free_regions); + if (state->body_regions != 0) + state->body_regions = cleanup_region_free(state->body_regions); +} |