Add support for dynamic BuildRequires

Supports new %generate_buildrequires section in the spec file which is executed
after %prep. Stdout is captured and turned into BuildRequires. These are then
checked. If they cannot be fulfilled a source package is created with all
BuildRequires and the build is terminated after that.

rpmbuild has now the following new build modes -br, -tr, -rr and exits with 11
if build requirements are not met.

That means for users:
* No %generate_buildrequires
  * rpmbuild -br is equivalent to rpmbuild -bs
  * rpmbuild -br --nodeps is equivalent to rpmbuild -bs
* %generate_buildrequires
  * rpmbuild -br will check dynamic BuildRequires
    * Satisfied → src.rpm
    * Unsatisfied → buildreqs.nosrc.rpm
  * rpmbuild -br --nodeps will always generate buildreqs.nosrc.rpm

Source packages contain
Requires: rpmlib(DynamicBuildRequires) <= 4.15.0-1
if the spec contains a %generate_buildrequires section and
Provide: rpmlib(DynamicBuildRequires) = 4.15.0-1
if the results been added to the source package.

Co-authored-by: Igor Gnatenko <i.gnatenko.brain@gmail.com>

build/build.c

@@ -71,6 +71,11 @@ rpmRC doScript(rpmSpec spec, rpmBuildFlags what, const char *name,
 	mPost = "%{__spec_prep_post}";
 	mCmd = "%{__spec_prep_cmd}";
 	break;
+    case RPMBUILD_BUILDREQUIRES:
+	mTemplate = "%{__spec_buildrequires_template}";
+	mPost = "%{__spec_buildrequires_post}";
+	mCmd = "%{__spec_buildrequires_cmd}";
+	break;
     case RPMBUILD_BUILD:
 	mTemplate = "%{__spec_build_template}";
 	mPost = "%{__spec_build_post}";
@@ -174,6 +179,52 @@ rpmRC doScript(rpmSpec spec, rpmBuildFlags what, const char *name,
     return rc;
 }
 
+static int doBuildRequires(rpmSpec spec, int test)
+{
+    StringBuf sb_stdout = NULL;
+    int outc;
+    ARGV_t output = NULL;
+
+    int rc = 1; /* assume failure */
+
+    if (!spec->buildrequires) {
+	rc = RPMRC_OK;
+	goto exit;
+    }
+
+    if ((rc = doScript(spec, RPMBUILD_BUILDREQUIRES, "%generate_buildrequires",
+		       getStringBuf(spec->buildrequires), test, &sb_stdout)))
+	goto exit;
+
+    /* add results to requires of the srpm */
+    argvSplit(&output, getStringBuf(sb_stdout), "\n\r");
+    outc = argvCount(output);
+
+    if (!outc) {
+	goto exit;
+    }
+
+    for (int i = 0; i < outc; i++) {
+	parseRCPOT(spec, spec->sourcePackage, output[i], RPMTAG_REQUIRENAME,
+		   0, 0, addReqProvPkg, NULL);
+    }
+
+    rpmdsPutToHeader(
+	*packageDependencies(spec->sourcePackage, RPMTAG_REQUIRENAME),
+	spec->sourcePackage->header);
+
+    parseRCPOT(spec, spec->sourcePackage,
+	       "rpmlib(DynamicBuildRequires) = 4.15.0-1",
+	       RPMTAG_PROVIDENAME, 0, RPMSENSE_FIND_PROVIDES | RPMSENSE_RPMLIB,
+	       addReqProvPkg, NULL);
+    rc = RPMRC_MISSINGBUILDREQUIRES;
+
+ exit:
+    freeStringBuf(sb_stdout);
+    free(output);
+    return rc;
+}
+
 static rpmRC doCheckBuildRequires(rpmts ts, rpmSpec spec, int test)
 {
     rpmRC rc = RPMRC_OK;
@@ -182,9 +233,9 @@ static rpmRC doCheckBuildRequires(rpmts ts, rpmSpec spec, int test)
     if (ps) {
 	rpmlog(RPMLOG_ERR, _("Failed build dependencies:\n"));
 	rpmpsPrint(NULL, ps);
-    }
-    if (ps != NULL)
 	rc = RPMRC_MISSINGBUILDREQUIRES;
+    }
+
     rpmpsFree(ps);
     return rc;
 }
@@ -230,6 +281,14 @@ static rpmRC buildSpec(rpmts ts, BTA_t buildArgs, rpmSpec spec, int what)
 	}
     } else {
 	int didBuild = (what & (RPMBUILD_PREP|RPMBUILD_BUILD|RPMBUILD_INSTALL));
+	int sourceOnly = ((what & RPMBUILD_PACKAGESOURCE) &&
+	   !(what & (RPMBUILD_BUILD|RPMBUILD_INSTALL|RPMBUILD_PACKAGEBINARY)));
+
+	if (!spec->buildrequires && sourceOnly) {
+		/* don't run prep if not needed for source build */
+		/* with(out) dynamic build requires*/
+	    what &= ~(RPMBUILD_PREP);
+	}
 
 	if ((what & RPMBUILD_CHECKBUILDREQUIRES) &&
 	    (rc = doCheckBuildRequires(ts, spec, test)))
@@ -240,6 +299,29 @@ static rpmRC buildSpec(rpmts ts, BTA_t buildArgs, rpmSpec spec, int what)
 			   getStringBuf(spec->prep), test, NULL)))
 		goto exit;
 
+	if (what & RPMBUILD_BUILDREQUIRES)
+            rc = doBuildRequires(spec, test);
+	if ((what & RPMBUILD_CHECKBUILDREQUIRES) &&
+	        (rc == RPMRC_MISSINGBUILDREQUIRES))
+	    rc = doCheckBuildRequires(ts, spec, test);
+	if (rc == RPMRC_MISSINGBUILDREQUIRES) {
+	    if (what & RPMBUILD_DUMPBUILDREQUIRES) {
+		/* Create buildreqs package */
+		char *nvr = headerGetAsString(spec->packages->header, RPMTAG_NVR);
+		rasprintf(&spec->sourceRpmName, "%s.buildreqs.nosrc.rpm", nvr);
+		free(nvr);
+		/* free sources to not include them in the buildreqs package */
+		spec->sources = freeSources(spec->sources);
+		spec->numSources = 0;
+		missing_buildreqs = 1;
+		what = RPMBUILD_PACKAGESOURCE;
+	    } else {
+		rc = RPMRC_OK;
+	    }
+	} else if (rc) {
+	    goto exit;
+	}
+
 	if ((what & RPMBUILD_BUILD) &&
 	    (rc = doScript(spec, RPMBUILD_BUILD, "%build",
 			   getStringBuf(spec->build), test, NULL)))

build/pack.c

@@ -782,6 +782,10 @@ rpmRC packageSources(rpmSpec spec, char **cookie)
     headerPutUint32(sourcePkg->header, RPMTAG_BUILDTIME, &(spec->buildTime), 1);
     headerPutUint32(sourcePkg->header, RPMTAG_SOURCEPACKAGE, &one, 1);
 
+    if (spec->buildrequires) {
+	(void) rpmlibNeedsFeature(sourcePkg, "DynamicBuildRequires", "4.15.0-1");
+    }
+
     /* XXX this should be %_srpmdir */
     {	sourcePkg->filename = rpmGetPath("%{_srcrpmdir}/", spec->sourceRpmName,NULL);
 	char *pkgcheck = rpmExpand("%{?_build_pkgcheck_srpm} ", sourcePkg->filename, NULL);

build/parseSpec.c

@@ -43,6 +43,7 @@ static const struct PartRec {
 } partList[] = {
     { PART_PREAMBLE,      LEN_AND_STR("%package")},
     { PART_PREP,          LEN_AND_STR("%prep")},
+    { PART_BUILDREQUIRES, LEN_AND_STR("%generate_buildrequires")},
     { PART_BUILD,         LEN_AND_STR("%build")},
     { PART_INSTALL,       LEN_AND_STR("%install")},
     { PART_CHECK,         LEN_AND_STR("%check")},
@@ -906,6 +907,10 @@ static rpmSpec parseSpec(const char *specFile, rpmSpecFlags flags,
 	case PART_PREP:
 	    parsePart = parsePrep(spec);
 	    break;
+	case PART_BUILDREQUIRES:
+	    parsePart = parseSimpleScript(spec, "%generate_buildrequires",
+					  &(spec->buildrequires));
+	    break;
 	case PART_BUILD:
 	    parsePart = parseSimpleScript(spec, "%build", &(spec->build));
 	    break;

build/reqprov.c

@@ -19,9 +19,15 @@ int addReqProv(Package pkg, rpmTagVal tagN,
 
     dsp = packageDependencies(pkg, tagN);
 
-    /* rpmlib() dependency sanity: only requires permitted, ensure sense bit */
+    /* rpmlib() dependency sanity:
+     * - Provides are permitted only for source packages
+     * - Otherwise only requires
+     * - Ensure sense bit
+     */
     if (rstreqn(N, "rpmlib(", sizeof("rpmlib(")-1)) {
-	if (tagN != RPMTAG_REQUIRENAME) return 1;
+	if (tagN != RPMTAG_REQUIRENAME &&
+	        (tagN == RPMTAG_PROVIDENAME && !(Flags & RPMSENSE_RPMLIB)))
+	    return 1;
 	Flags |= RPMSENSE_RPMLIB;
     }
 

build/rpmbuild.h

@@ -36,6 +36,8 @@ enum rpmBuildFlags_e {
     RPMBUILD_FILE_LIST  = (1 << 17),    /*!< rpmSpecPkgGetSection: %files */
     RPMBUILD_POLICY     = (1 << 18),    /*!< rpmSpecPkgGetSection: %policy */
     RPMBUILD_CHECKBUILDREQUIRES	= (1 <<  19),	/*!< Check %%buildrequires. */
+    RPMBUILD_BUILDREQUIRES	= (1 <<  20), /*!< Execute %%buildrequires. */
+    RPMBUILD_DUMPBUILDREQUIRES	= (1 <<  21), /*!< Write buildrequires.nosrc.rpm. */
 
     RPMBUILD_NOBUILD	= (1 << 31)	/*!< Don't execute or package. */
 };
@@ -109,7 +111,9 @@ rpmds rpmSpecDS(rpmSpec spec, rpmTagVal tag);
  * @param ts		rpm transaction set
  * @param spec		spec file control structure
  * @param buildArgs	build arguments
- * @return		RPMRC_OK on success, RPMRC_MISSINGBUILDREQUIRES or 1
+ * @return		0 on success, 1 on build error,
+ *			RPMRC_MISSINGBUILDREQUIRES on missing build
+ *			requirements
  */
 int rpmSpecBuild(rpmts ts, rpmSpec spec, BTA_t buildArgs);
 

build/rpmbuild_internal.h

@@ -140,6 +140,7 @@ struct rpmSpec_s {
     rpmstrPool pool;
 
     StringBuf prep;		/*!< %prep scriptlet. */
+    StringBuf buildrequires;	/*!< %buildrequires scriptlet. */
     StringBuf build;		/*!< %build scriptlet. */
     StringBuf install;		/*!< %install scriptlet. */
     StringBuf check;		/*!< %check scriptlet. */
@@ -237,7 +238,8 @@ typedef enum rpmParseState_e {
     PART_EMPTY			= 39+PART_BASE, /*!< */
     PART_PATCHLIST		= 40+PART_BASE, /*!< */
     PART_SOURCELIST		= 41+PART_BASE, /*!< */
-    PART_LAST			= 42+PART_BASE  /*!< */
+    PART_BUILDREQUIRES		= 42+PART_BASE, /*!< */
+    PART_LAST			= 43+PART_BASE  /*!< */
 } rpmParseState; 
 
 

doc/rpmbuild.8

@@ -11,13 +11,13 @@ rpmbuild \- Build RPM Package(s)
 .PP
 
 
-\fBrpmbuild\fR {\fB-ba|-bb|-bp|-bc|-bi|-bl|-bs\fR} [\fBrpmbuild-options\fR] \fB\fISPECFILE\fB\fR\fI ...\fR
+\fBrpmbuild\fR {\fB-ba|-bb|-bp|-bc|-bi|-bl|-bs|-br\fR} [\fBrpmbuild-options\fR] \fB\fISPECFILE\fB\fR\fI ...\fR
 
 
-\fBrpmbuild\fR {\fB-ra|-rb|-rp|-rc|-ri|-rl|-rs\fR} [\fBrpmbuild-options\fR] \fB\fISOURCEPACKAGE\fB\fR\fI ...\fR
+\fBrpmbuild\fR {\fB-ra|-rb|-rp|-rc|-ri|-rl|-rs|-rr\fR} [\fBrpmbuild-options\fR] \fB\fISOURCEPACKAGE\fB\fR\fI ...\fR
 
 
-\fBrpmbuild\fR {\fB-ta|-tb|-tp|-tc|-ti|-tl|-ts\fR} [\fBrpmbuild-options\fR] \fB\fITARBALL\fB\fR\fI ...\fR
+\fBrpmbuild\fR {\fB-ta|-tb|-tp|-tc|-ti|-tl|-ts|-tr\fR} [\fBrpmbuild-options\fR] \fB\fITARBALL\fB\fR\fI ...\fR
 
 
 
@@ -162,6 +162,9 @@ exists.
 .TP
 \fB-bs\fR
 Build just the source package.
+.TP
+\fB-br\fR
+Build just the source package - but calculate and include the dynamic build requires.
 .PP
 The following options may also be used:
 .TP

lib/rpmds.c

@@ -1249,6 +1249,9 @@ static const struct rpmlibProvides_s rpmlibProvides[] = {
     { "rpmlib(RichDependencies)",    "4.12.0-1",
 	(		RPMSENSE_EQUAL),
     N_("support for rich dependencies.") },
+    { "rpmlib(DynamicBuildRequires)", "4.15.0-1",
+	(RPMSENSE_RPMLIB|RPMSENSE_EQUAL),
+    N_("support for dynamic buildrequires.") },
 #ifdef HAVE_ZSTD
     { "rpmlib(PayloadIsZstd)",		"5.4.18-1",
 	(RPMSENSE_RPMLIB|RPMSENSE_EQUAL),

macros.in

@@ -846,6 +846,21 @@ package or when debugging this package.\
 #%{__spec_prep_post}\
 #%{nil}
 
+%__spec_buildrequires_shell	%{___build_shell}
+%__spec_buildrequires_args	%{___build_args}
+%__spec_buildrequires_cmd	%{___build_cmd}
+%__spec_buildrequires_pre	%{___build_pre}
+%__spec_buildrequires_body	%{___build_body}
+%__spec_buildrequires_post	%{___build_post}
+%__spec_buildrequires_template	#!%{__spec_buildrequires_shell}\
+%{__spec_buildrequires_pre}\
+%{nil}
+
+#%{__spec_buildrequires_body}\
+#%{__spec_buildrequires_post}\
+#%{nil}
+
+
 %__spec_build_shell	%{___build_shell}
 %__spec_build_args	%{___build_args}
 %__spec_build_cmd	%{___build_cmd}

rpmbuild.c

@@ -38,20 +38,23 @@ static struct rpmBuildArguments_s rpmBTArgs;
 #define	POPT_BL			0x626c
 #define	POPT_BP			0x6270
 #define	POPT_BS			0x6273
+#define	POPT_BR			0x6272
 #define	POPT_RA			0x4261
 #define	POPT_RB			0x4262
 #define	POPT_RC			0x4263
 #define	POPT_RI			0x4269
 #define	POPT_RL			0x426c
 #define	POPT_RP			0x4270
 #define	POPT_RS			0x4273
+#define	POPT_RR			0x4272
 #define	POPT_TA			0x7461
 #define	POPT_TB			0x7462
 #define	POPT_TC			0x7463
 #define	POPT_TI			0x7469
 #define	POPT_TL			0x746c
 #define	POPT_TP			0x7470
 #define	POPT_TS			0x7473
+#define	POPT_TR			0x7472
 
 extern int _fsm_debug;
 
@@ -81,20 +84,23 @@ static void buildArgCallback( poptContext con,
     case POPT_BL:
     case POPT_BP:
     case POPT_BS:
+    case POPT_BR:
     case POPT_RA:
     /* case POPT_RB: same value as POPT_REBUILD */
     case POPT_RC:
     case POPT_RI:
     case POPT_RL:
     case POPT_RP:
     case POPT_RS:
+    case POPT_RR:
     case POPT_TA:
     case POPT_TB:
     case POPT_TC:
     case POPT_TI:
     case POPT_TL:
     case POPT_TP:
     case POPT_TS:
+    case POPT_TR:
 	if (opt->val == POPT_BS || opt->val == POPT_TS)
 	    noDeps = 1;
 	if (buildMode == '\0' && buildChar == '\0') {
@@ -156,6 +162,9 @@ static struct poptOption rpmBuildPoptTable[] = {
  { "bs", 0, POPT_ARGFLAG_ONEDASH, 0, POPT_BS,
 	N_("build source package only from <specfile>"),
 	N_("<specfile>") },
+ { "br", 0, POPT_ARGFLAG_ONEDASH, 0, POPT_BR,
+	N_("build source package only from <specfile> - calculate dynamic build requires"),
+	N_("<specfile>") },
 
  { "rp", 0, POPT_ARGFLAG_ONEDASH, 0, POPT_RP,
 	N_("build through %prep (unpack sources and apply patches) from <source package>"),
@@ -178,6 +187,9 @@ static struct poptOption rpmBuildPoptTable[] = {
  { "rs", 0, POPT_ARGFLAG_ONEDASH, 0, POPT_RS,
 	N_("build source package only from <source package>"),
 	N_("<source package>") },
+ { "rr", 0, POPT_ARGFLAG_ONEDASH, 0, POPT_RR,
+	N_("build source package only from <source package> - calculate dynamic build requires"),
+	N_("<source package>") },
 
  { "tp", 0, POPT_ARGFLAG_ONEDASH, 0, POPT_TP,
 	N_("build through %prep (unpack sources and apply patches) from <tarball>"),
@@ -200,7 +212,9 @@ static struct poptOption rpmBuildPoptTable[] = {
  { "ts", 0, POPT_ARGFLAG_ONEDASH, 0, POPT_TS,
 	N_("build source package only from <tarball>"),
 	N_("<tarball>") },
-
+ { "tr", 0, POPT_ARGFLAG_ONEDASH, 0, POPT_TR,
+	N_("build source package only from <tarball> - calculate dynamic build requires"),
+	N_("<tarball>") },
  { "rebuild", '\0', 0, 0, POPT_REBUILD,
 	N_("build binary package from <source package>"),
 	N_("<source package>") },
@@ -623,7 +637,9 @@ int main(int argc, char *argv[])
 	    break;
     case 'c':
 	ba->buildAmount |= RPMBUILD_BUILD;
+	ba->buildAmount |= RPMBUILD_BUILDREQUIRES;
 	if (!noDeps) {
+	    ba->buildAmount |= RPMBUILD_DUMPBUILDREQUIRES;
 	    ba->buildAmount |= RPMBUILD_CHECKBUILDREQUIRES;
 	}
 	if ((buildChar == 'c') && shortCircuit)
@@ -634,6 +650,12 @@ int main(int argc, char *argv[])
     case 'l':
 	ba->buildAmount |= RPMBUILD_FILECHECK;
 	break;
+    case 'r':
+	ba->buildAmount |= RPMBUILD_PREP;
+	ba->buildAmount |= RPMBUILD_BUILDREQUIRES;
+	ba->buildAmount |= RPMBUILD_DUMPBUILDREQUIRES;
+	if (!noDeps)
+	    ba->buildAmount |= RPMBUILD_CHECKBUILDREQUIRES;
     case 's':
 	ba->buildAmount |= RPMBUILD_PACKAGESOURCE;
 	break;