diff options
Diffstat (limited to 'lib/order.c')
-rw-r--r-- | lib/order.c | 655 |
1 files changed, 655 insertions, 0 deletions
diff --git a/lib/order.c b/lib/order.c new file mode 100644 index 0000000..34ad795 --- /dev/null +++ b/lib/order.c @@ -0,0 +1,655 @@ +/** \ingroup rpmts + * \file lib/depends.c + */ + +#include "system.h" + +#include <rpm/rpmtag.h> +#include <rpm/rpmmacro.h> +#include <rpm/rpmlog.h> +#include <rpm/rpmds.h> + +#include "lib/rpmte_internal.h" /* XXX tsortInfo_s */ +#include "lib/rpmts_internal.h" + +#include "debug.h" + +/* + * Strongly Connected Components + * set of packages (indirectly) requiering each other + */ +struct scc_s { + int count; /* # of external requires this SCC has */ + /* int qcnt; # of external requires pointing to this SCC */ + int size; /* # of members */ + tsortInfo * members; +}; + +typedef struct scc_s * scc; + +struct relation_s { + tsortInfo rel_suc; // pkg requiring this package + rpmsenseFlags rel_flags; // accumulated flags of the requirements + struct relation_s * rel_next; +}; + +typedef struct relation_s * relation; + +struct tsortInfo_s { + rpmte te; + int tsi_count; // #pkgs this pkg requires + int tsi_qcnt; // #pkgs requiring this package + int tsi_reqx; // requires Idx/mark as (queued/loop) + struct relation_s * tsi_relations; + struct relation_s * tsi_forward_relations; + tsortInfo tsi_suc; // used for queuing (addQ) + int tsi_SccIdx; // # of the SCC the node belongs to + // (1 for trivial SCCs) + int tsi_SccLowlink; // used for SCC detection +}; + +static void rpmTSIFree(tsortInfo tsi) +{ + relation rel; + + while (tsi->tsi_relations != NULL) { + rel = tsi->tsi_relations; + tsi->tsi_relations = tsi->tsi_relations->rel_next; + rel = _free(rel); + } + while (tsi->tsi_forward_relations != NULL) { + rel = tsi->tsi_forward_relations; + tsi->tsi_forward_relations = \ + tsi->tsi_forward_relations->rel_next; + rel = _free(rel); + } +} + +static inline int addSingleRelation(rpmte p, + rpmte q, + rpmsenseFlags dsflags) +{ + struct tsortInfo_s *tsi_p, *tsi_q; + relation rel; + rpmElementType teType = rpmteType(p); + rpmsenseFlags flags; + + /* Avoid deps outside this transaction and self dependencies */ + if (q == NULL || q == p) + return 0; + + /* Erasures are reversed installs. */ + if (teType == TR_REMOVED) { + rpmte r = p; + p = q; + q = r; + flags = isErasePreReq(dsflags); + } else { + flags = isInstallPreReq(dsflags); + } + + /* map legacy prereq to pre/preun as needed */ + if (isLegacyPreReq(dsflags)) { + flags |= (teType == TR_ADDED) ? + RPMSENSE_SCRIPT_PRE : RPMSENSE_SCRIPT_PREUN; + } + + tsi_p = rpmteTSI(p); + tsi_q = rpmteTSI(q); + + /* if relation got already added just update the flags */ + if (tsi_q->tsi_relations && tsi_q->tsi_relations->rel_suc == tsi_p) { + tsi_q->tsi_relations->rel_flags |= flags; + tsi_p->tsi_forward_relations->rel_flags |= flags; + return 0; + } + + /* Record next "q <- p" relation (i.e. "p" requires "q"). */ + if (p != q) { + /* bump p predecessor count */ + tsi_p->tsi_count++; + } + + rel = xcalloc(1, sizeof(*rel)); + rel->rel_suc = tsi_p; + rel->rel_flags = flags; + + rel->rel_next = tsi_q->tsi_relations; + tsi_q->tsi_relations = rel; + if (p != q) { + /* bump q successor count */ + tsi_q->tsi_qcnt++; + } + + rel = xcalloc(1, sizeof(*rel)); + rel->rel_suc = tsi_q; + rel->rel_flags = flags; + + rel->rel_next = tsi_p->tsi_forward_relations; + tsi_p->tsi_forward_relations = rel; + + return 0; +} + +/** + * Record next "q <- p" relation (i.e. "p" requires "q"). + * @param ts transaction set + * @param p predecessor (i.e. package that "Requires: q") + * @param requires relation + * @return 0 always + */ +static inline int addRelation(rpmts ts, + rpmal al, + rpmte p, + rpmds requires) +{ + rpmte q; + rpmsenseFlags dsflags; + + dsflags = rpmdsFlags(requires); + + /* Avoid dependendencies which are not relevant for ordering */ + if (dsflags & (RPMSENSE_RPMLIB|RPMSENSE_CONFIG|RPMSENSE_PRETRANS|RPMSENSE_POSTTRANS)) + return 0; + + q = rpmalSatisfiesDepend(al, requires); + + /* Avoid deps outside this transaction and self dependencies */ + if (q == NULL || q == p) + return 0; + + addSingleRelation(p, q, dsflags); + + return 0; +} + +/* + * Collections might have special ordering requirements. Notably + * sepolicy collection requires having all the bits in the collection + * close to each other. We try to ensure this by creating a strongly + * connected component of such "grouped" collections, by introducing + * an artificial relation loop across the all its members. + */ +static int addCollRelations(rpmal al, rpmte p, ARGV_t *seenColls) +{ + ARGV_const_t qcolls; + + for (qcolls = rpmteCollections(p); qcolls && *qcolls; qcolls++) { + char * flags; + if (argvSearch(*seenColls, *qcolls, NULL)) + continue; + + flags = rstrscat(NULL, "%{__collection_", *qcolls, "_flags}", NULL); + if (rpmExpandNumeric(flags) & 0x1) { + rpmte *tes = rpmalAllInCollection(al, *qcolls); + for (rpmte *te = tes; te && *te; te++) { + rpmte next = (*(te + 1) != NULL) ? *(te + 1) : *tes; + addSingleRelation(*te, next, RPMSENSE_ANY); + } + _free(tes); + } + free(flags); + + argvAdd(seenColls, *qcolls); + argvSort(*seenColls, NULL); + } + + return 0; +} + +/** + * Add element to list sorting by tsi_qcnt. + * @param p new element + * @retval qp address of first element + * @retval rp address of last element + * @param prefcolor + */ +static void addQ(tsortInfo p, tsortInfo * qp, tsortInfo * rp, + rpm_color_t prefcolor) +{ + tsortInfo q, qprev; + rpm_color_t pcolor = rpmteColor(p->te); + int tailcond; + + /* Mark the package as queued. */ + p->tsi_reqx = 1; + + if ((*rp) == NULL) { /* 1st element */ + /* FIX: double indirection */ + (*rp) = (*qp) = p; + return; + } + + if (rpmteType(p->te) == TR_ADDED) + tailcond = (pcolor && pcolor != prefcolor); + else + tailcond = (pcolor && pcolor == prefcolor); + + /* Find location in queue using metric tsi_qcnt and color. */ + for (qprev = NULL, q = (*qp); + q != NULL; + qprev = q, q = q->tsi_suc) + { + /* Place preferred color towards queue head on install, tail on erase */ + if (tailcond && (pcolor != rpmteColor(q->te))) + continue; + + if (q->tsi_qcnt <= p->tsi_qcnt) + break; + } + + if (qprev == NULL) { /* insert at beginning of list */ + p->tsi_suc = q; + (*qp) = p; /* new head */ + } else if (q == NULL) { /* insert at end of list */ + qprev->tsi_suc = p; + (*rp) = p; /* new tail */ + } else { /* insert between qprev and q */ + p->tsi_suc = q; + qprev->tsi_suc = p; + } +} + +typedef struct sccData_s { + int index; /* DFS node number counter */ + tsortInfo *stack; /* Stack of nodes */ + int stackcnt; /* Stack top counter */ + scc SCCs; /* Array of SCC's found */ + int sccCnt; /* Number of SCC's found */ +} * sccData; + +static void tarjan(sccData sd, tsortInfo tsi) { + tsortInfo tsi_q; + relation rel; + + /* use negative index numbers */ + sd->index--; + /* Set the depth index for p */ + tsi->tsi_SccIdx = sd->index; + tsi->tsi_SccLowlink = sd->index; + + sd->stack[sd->stackcnt++] = tsi; /* Push p on the stack */ + for (rel=tsi->tsi_relations; rel != NULL; rel=rel->rel_next) { + /* Consider successors of p */ + tsi_q = rel->rel_suc; + if (tsi_q->tsi_SccIdx > 0) + /* Ignore already found SCCs */ + continue; + if (tsi_q->tsi_SccIdx == 0){ + /* Was successor q not yet visited? */ + tarjan(sd, tsi_q); /* Recurse */ + /* negative index numers: use max as it is closer to 0 */ + tsi->tsi_SccLowlink = ( + tsi->tsi_SccLowlink > tsi_q->tsi_SccLowlink + ? tsi->tsi_SccLowlink : tsi_q->tsi_SccLowlink); + } else { + tsi->tsi_SccLowlink = ( + tsi->tsi_SccLowlink > tsi_q->tsi_SccIdx + ? tsi->tsi_SccLowlink : tsi_q->tsi_SccIdx); + } + } + + if (tsi->tsi_SccLowlink == tsi->tsi_SccIdx) { + /* v is the root of an SCC? */ + if (sd->stack[sd->stackcnt-1] == tsi) { + /* ignore trivial SCCs */ + tsi_q = sd->stack[--sd->stackcnt]; + tsi_q->tsi_SccIdx = 1; + } else { + int stackIdx = sd->stackcnt; + do { + tsi_q = sd->stack[--stackIdx]; + tsi_q->tsi_SccIdx = sd->sccCnt; + } while (tsi_q != tsi); + + stackIdx = sd->stackcnt; + do { + tsi_q = sd->stack[--stackIdx]; + /* Calculate count for the SCC */ + sd->SCCs[sd->sccCnt].count += tsi_q->tsi_count; + /* Subtract internal relations */ + for (rel=tsi_q->tsi_relations; rel != NULL; + rel=rel->rel_next) { + if (rel->rel_suc != tsi_q && + rel->rel_suc->tsi_SccIdx == sd->sccCnt) + sd->SCCs[sd->sccCnt].count--; + } + } while (tsi_q != tsi); + sd->SCCs[sd->sccCnt].size = sd->stackcnt - stackIdx; + /* copy members */ + sd->SCCs[sd->sccCnt].members = xcalloc(sd->SCCs[sd->sccCnt].size, + sizeof(tsortInfo)); + memcpy(sd->SCCs[sd->sccCnt].members, sd->stack + stackIdx, + sd->SCCs[sd->sccCnt].size * sizeof(tsortInfo)); + sd->stackcnt = stackIdx; + sd->sccCnt++; + } + } +} + +/* Search for SCCs and return an array last entry has a .size of 0 */ +static scc detectSCCs(tsortInfo orderInfo, int nelem, int debugloops) +{ + /* Set up data structures needed for the tarjan algorithm */ + scc SCCs = xcalloc(nelem+3, sizeof(*SCCs)); + tsortInfo *stack = xcalloc(nelem, sizeof(*stack)); + struct sccData_s sd = { 0, stack, 0, SCCs, 2 }; + + for (int i = 0; i < nelem; i++) { + tsortInfo tsi = &orderInfo[i]; + /* Start a DFS at each node */ + if (tsi->tsi_SccIdx == 0) + tarjan(&sd, tsi); + } + + free(stack); + + SCCs = xrealloc(SCCs, (sd.sccCnt+1)*sizeof(struct scc_s)); + + /* Debug output */ + if (sd.sccCnt > 2) { + int msglvl = debugloops ? RPMLOG_WARNING : RPMLOG_DEBUG; + rpmlog(msglvl, "%i Strongly Connected Components\n", sd.sccCnt-2); + for (int i = 2; i < sd.sccCnt; i++) { + rpmlog(msglvl, "SCC #%i: %i members (%i external dependencies)\n", + i-1, SCCs[i].size, SCCs[i].count); + + /* loop over members */ + for (int j = 0; j < SCCs[i].size; j++) { + tsortInfo member = SCCs[i].members[j]; + rpmlog(msglvl, "\t%s\n", rpmteNEVRA(member->te)); + /* show relations between members */ + relation rel = member->tsi_forward_relations; + for (; rel != NULL; rel=rel->rel_next) { + if (rel->rel_suc->tsi_SccIdx!=i) continue; + rpmlog(msglvl, "\t\t%s %s\n", + rel->rel_flags ? "=>" : "->", + rpmteNEVRA(rel->rel_suc->te)); + } + } + } + } + return SCCs; +} + +static void collectTE(rpm_color_t prefcolor, tsortInfo q, + rpmte * newOrder, int * newOrderCount, + scc SCCs, + tsortInfo * queue_end, + tsortInfo * outer_queue, + tsortInfo * outer_queue_end) +{ + char deptypechar = (rpmteType(q->te) == TR_REMOVED ? '-' : '+'); + + if (rpmIsDebug()) { + int depth = 1; + /* figure depth in tree for nice formatting */ + for (rpmte p = q->te; (p = rpmteParent(p)); depth++) {} + rpmlog(RPMLOG_DEBUG, "%5d%5d%5d%5d %*s%c%s\n", + *newOrderCount, q->tsi_count, q->tsi_qcnt, + depth, (2 * depth), "", + deptypechar, rpmteNEVRA(q->te)); + } + + newOrder[*newOrderCount] = q->te; + (*newOrderCount)++; + + /* T6. Erase relations. */ + for (relation rel = q->tsi_relations; rel != NULL; rel = rel->rel_next) { + tsortInfo p = rel->rel_suc; + /* ignore already collected packages */ + if (p->tsi_SccIdx == 0) continue; + if (p == q) continue; + + if (p && (--p->tsi_count) == 0) { + (void) rpmteSetParent(p->te, q->te); + + if (q->tsi_SccIdx > 1 && q->tsi_SccIdx != p->tsi_SccIdx) { + /* Relation point outside of this SCC: add to outside queue */ + assert(outer_queue != NULL && outer_queue_end != NULL); + addQ(p, outer_queue, outer_queue_end, prefcolor); + } else { + addQ(p, &q->tsi_suc, queue_end, prefcolor); + } + } + if (p && p->tsi_SccIdx > 1 && + p->tsi_SccIdx != q->tsi_SccIdx) { + if (--SCCs[p->tsi_SccIdx].count == 0) { + /* New SCC is ready, add this package as representative */ + (void) rpmteSetParent(p->te, q->te); + + if (outer_queue != NULL) { + addQ(p, outer_queue, outer_queue_end, prefcolor); + } else { + addQ(p, &q->tsi_suc, queue_end, prefcolor); + } + } + } + } + q->tsi_SccIdx = 0; +} + +static void collectSCC(rpm_color_t prefcolor, tsortInfo p_tsi, + rpmte * newOrder, int * newOrderCount, + scc SCCs, tsortInfo * queue_end) +{ + int sccNr = p_tsi->tsi_SccIdx; + struct scc_s SCC = SCCs[sccNr]; + int i; + int start, end; + relation rel; + + /* remove p from the outer queue */ + tsortInfo outer_queue_start = p_tsi->tsi_suc; + p_tsi->tsi_suc = NULL; + + /* + * Run a multi source Dijkstra's algorithm to find relations + * that can be zapped with least danger to pre reqs. + * As weight of the edges is always 1 it is not necessary to + * sort the vertices by distance as the queue gets them + * already in order + */ + + /* can use a simple queue as edge weights are always 1 */ + tsortInfo * queue = xmalloc((SCC.size+1) * sizeof(*queue)); + + /* + * Find packages that are prerequired and use them as + * starting points for the Dijkstra algorithm + */ + start = end = 0; + for (i = 0; i < SCC.size; i++) { + tsortInfo tsi = SCC.members[i]; + tsi->tsi_SccLowlink = INT_MAX; + for (rel=tsi->tsi_forward_relations; rel != NULL; rel=rel->rel_next) { + if (rel->rel_flags && rel->rel_suc->tsi_SccIdx == sccNr) { + if (rel->rel_suc != tsi) { + tsi->tsi_SccLowlink = 0; + queue[end++] = tsi; + } else { + tsi->tsi_SccLowlink = INT_MAX/2; + } + break; + } + } + } + + if (start == end) { /* no regular prereqs; add self prereqs to queue */ + for (i = 0; i < SCC.size; i++) { + tsortInfo tsi = SCC.members[i]; + if (tsi->tsi_SccLowlink != INT_MAX) { + queue[end++] = tsi; + } + } + } + + /* Do Dijkstra */ + while (start != end) { + tsortInfo tsi = queue[start++]; + for (rel=tsi->tsi_forward_relations; rel != NULL; rel=rel->rel_next) { + tsortInfo next_tsi = rel->rel_suc; + if (next_tsi->tsi_SccIdx != sccNr) continue; + if (next_tsi->tsi_SccLowlink > tsi->tsi_SccLowlink+1) { + next_tsi->tsi_SccLowlink = tsi->tsi_SccLowlink + 1; + queue[end++] = rel->rel_suc; + } + } + } + queue = _free(queue); + + + while (1) { + tsortInfo best = NULL; + tsortInfo inner_queue_start, inner_queue_end; + int best_score = 0; + + /* select best candidate to start with */ + for (int i = 0; i < SCC.size; i++) { + tsortInfo tsi = SCC.members[i]; + if (tsi->tsi_SccIdx == 0) /* package already collected */ + continue; + if (tsi->tsi_SccLowlink >= best_score) { + best = tsi; + best_score = tsi->tsi_SccLowlink; + } + } + + if (best == NULL) /* done */ + break; + + /* collect best candidate and all packages that get freed */ + inner_queue_start = inner_queue_end = NULL; + addQ(best, &inner_queue_start, &inner_queue_end, prefcolor); + + for (; inner_queue_start != NULL; + inner_queue_start = inner_queue_start->tsi_suc) { + /* Mark the package as unqueued. */ + inner_queue_start->tsi_reqx = 0; + collectTE(prefcolor, inner_queue_start, newOrder, newOrderCount, + SCCs, &inner_queue_end, &outer_queue_start, queue_end); + } + } + + /* restore outer queue */ + p_tsi->tsi_suc = outer_queue_start; +} + +int rpmtsOrder(rpmts ts) +{ + tsMembers tsmem = rpmtsMembers(ts); + rpm_color_t prefcolor = rpmtsPrefColor(ts); + rpmtsi pi; rpmte p; + tsortInfo q, r; + rpmte * newOrder; + int newOrderCount = 0; + int rc; + rpmal erasedPackages = rpmalCreate(5, rpmtsColor(ts), prefcolor); + scc SCCs; + int nelem = rpmtsNElements(ts); + tsortInfo sortInfo = xcalloc(nelem, sizeof(struct tsortInfo_s)); + ARGV_t seenColls = NULL; + + (void) rpmswEnter(rpmtsOp(ts, RPMTS_OP_ORDER), 0); + + /* Create erased package index. */ + pi = rpmtsiInit(ts); + while ((p = rpmtsiNext(pi, TR_REMOVED)) != NULL) { + rpmalAdd(erasedPackages, p); + } + pi = rpmtsiFree(pi); + + for (int i = 0; i < nelem; i++) { + sortInfo[i].te = tsmem->order[i]; + rpmteSetTSI(tsmem->order[i], &sortInfo[i]); + } + + /* Record relations. */ + rpmlog(RPMLOG_DEBUG, "========== recording tsort relations\n"); + pi = rpmtsiInit(ts); + while ((p = rpmtsiNext(pi, 0)) != NULL) { + rpmal al = (rpmteType(p) == TR_REMOVED) ? + erasedPackages : tsmem->addedPackages; + rpmds requires = rpmdsInit(rpmteDS(p, RPMTAG_REQUIRENAME)); + rpmds order = rpmdsInit(rpmteDS(p, RPMTAG_ORDERNAME)); + + while (rpmdsNext(requires) >= 0) { + /* Record next "q <- p" relation (i.e. "p" requires "q"). */ + (void) addRelation(ts, al, p, requires); + } + + while (rpmdsNext(order) >= 0) { + /* Record next "q <- p" ordering request */ + (void) addRelation(ts, al, p, order); + } + + addCollRelations(al, p, &seenColls); + } + + seenColls = argvFree(seenColls); + pi = rpmtsiFree(pi); + + newOrder = xcalloc(tsmem->orderCount, sizeof(*newOrder)); + SCCs = detectSCCs(sortInfo, nelem, (rpmtsFlags(ts) & RPMTRANS_FLAG_DEPLOOPS)); + + rpmlog(RPMLOG_DEBUG, "========== tsorting packages (order, #predecessors, #succesors, depth)\n"); + + for (int i = 0; i < 2; i++) { + /* Do two separate runs: installs first - then erases */ + int oType = !i ? TR_ADDED : TR_REMOVED; + q = r = NULL; + /* Scan for zeroes and add them to the queue */ + for (int e = 0; e < nelem; e++) { + tsortInfo p = &sortInfo[e]; + if (rpmteType(p->te) != oType) continue; + if (p->tsi_count != 0) + continue; + p->tsi_suc = NULL; + addQ(p, &q, &r, prefcolor); + } + + /* Add one member of each leaf SCC */ + for (int i = 2; SCCs[i].members != NULL; i++) { + tsortInfo member = SCCs[i].members[0]; + if (SCCs[i].count == 0 && rpmteType(member->te) == oType) { + addQ(member, &q, &r, prefcolor); + } + } + + while (q != NULL) { + /* Mark the package as unqueued. */ + q->tsi_reqx = 0; + if (q->tsi_SccIdx > 1) { + collectSCC(prefcolor, q, newOrder, &newOrderCount, SCCs, &r); + } else { + collectTE(prefcolor, q, newOrder, &newOrderCount, SCCs, &r, + NULL, NULL); + } + q = q->tsi_suc; + } + } + + /* Clean up tsort data */ + for (int i = 0; i < nelem; i++) { + rpmteSetTSI(tsmem->order[i], NULL); + rpmTSIFree(&sortInfo[i]); + } + free(sortInfo); + + assert(newOrderCount == tsmem->orderCount); + + tsmem->order = _free(tsmem->order); + tsmem->order = newOrder; + tsmem->orderAlloced = tsmem->orderCount; + rc = 0; + + for (int i = 2; SCCs[i].members != NULL; i++) { + free(SCCs[i].members); + } + free(SCCs); + rpmalFree(erasedPackages); + + (void) rpmswExit(rpmtsOp(ts, RPMTS_OP_ORDER), 0); + + return rc; +} |