programmatically retrieve rpm package details

Programmatically Retrieve RPM Package Details

Programmatically Retrieve RPMPackage Details

Finnbarr P. Murphy([email protected])

Recently, I needed to retrieve details about software packages installed on Fedora 15, Red HatEnterprise Linux, CentOS and other distributions which distribute their software packages usingthe RPM Package Manager. To my surprise, what should have been a relatively simple task turnedout to be quite messy because of changes in the RPM library APIs and internal format over the lastfew years. In this post, I demonstrate how to retrieve information about RPM packages using Cand Python.

RPM is a command-line or API driven package management system capable of installing,uninstalling, verifying, querying, and updating Linux or Unix software packages. Each softwarepackage consists of an archive of files together with information about the package such as itsversion number, a summary and a description, and dependency information. There is also a libraryAPI to enable developers to manage such transactions from compiled programming languagessuch as C or scripting languages such Python. Package files are written to disk in network byteorder. If necessary, RPM automatically converts data to host byte order when the package file isread.

RPM was initially developed in 1997 by Erik Troan and Marc Ewing for use in the Red Hat Linuxdistribution. For many years it was an opensource project which did not receive much love orattention. That picture changed in early 2007 when two separate (and competing) developmentcommunities were launched.

The more prominent RPM development community is rpm.org which is led by Red Hat. Accordingto their website:

After a long development break rpm.org was relaunched in 2007 with the goal toreclaim the position as upstream home of RPM. As a first step patches that had piledup in the different distributions have been integrated into the code base as far aspossible. We want RPM not be the province of one company, or a small set ofdevelopers. It needs to be developed in an open community, consumed andcontributed to by many companies, users, distributions, and developers. We thereforewelcome any and all contributors.….RPM will stay backward compatible to 4.4.2 for a quite long time. It is essential thatthird party packages can be installed without the need to recompile them – especiallyfor enterprise distributions.

In May 2007 Red Hat hired Panu Matilainen to work on the RPM project. The first major coderevision was in July 2007; version 4.8 was released in January 2010, and 4.9 in March 2011. Thisversion is used by distributions such as Fedora, Red Hat Enterprise Linux, openSUSE, SUSE LinuxEnterprise and CentOS.

The other RPM development community is rpm5.org which is lead by Jeff Johnson who was amaintainer of RPM whilst an employee of Red Hat. RPM version 5.0 was released in May 2007.

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08-15-2011 Copyright 2004-2011 Finnbarr P. Murphy. All rights reserved. 1/16

http://blog.fpmurphy.com/2011/08/programmatically-retrieve-rpm-package-details.html

http://blog.fpmurphy.com/2011/08/programmatically-retrieve-rpm-package-details.html

http://en.wikipedia.org/wiki/RPM_Package_Manager

http://lwn.net/Articles/214255/

http://rpm.org

http://laiskiainen.org/

http://www.mandriva.com

http://rpm5.org


Their latest version is 5.3.11 dated 02-Jun-2011. This version of RPM is used by distributions suchas Unity Linux and cAos Linux, and also by the OpenPKG project which provides packages forsome other Unix-like platforms. Apparently Mandriva has recently switched to it also althoughthere seems to be some controversy about that particular decision.

The format of an RPM package is binary and consists of three sections in the following order:

The lead section identifies the file as an RPM file. It contains a number of obsolete headers●

which in previous previous versions of RPM were used to store information used internally byRPM. Today, however, the lead section’s only purpose is to make it easy to identify an RPMpackage file.The signature section contains information that can be used to verify the integrity, and●

optionally, the authenticity of the majority of the package. This section is implemented using aheader structure (see below).The header section contains the package metadata such as name, version, architecture, list of●

files included and suchlike. It too is implemented as a header structure.Th final section contains the actual file archive, which is usually in cpio format, compressed with●

gzip but more recent versions of RPM can also use bzip2, lzma or xz compression and xar (XMLArchive) is supported by RPM 5.0.

Here is what the lead contains. Do not use anything from the lead except the major number andsignature type.

struct rpmlead_s { unsigned char magic[4]; unsigned char major; unsigned char minor; short type; short archnum; char name[66]; short osnum; short signature_type; /*!< Signature header type (RPMSIG_HEADERSIG) */char reserved[16]; /*!< Pad to 96 bytes -- 8 byte aligned! */};

The header structure concept is RPM's solution to the problem of easily manipulating informationin a standardized way. The purpose of a header structure is to contain zero or more pieces of data.There are three sections to each header structure. The first section is known as the headerstructure header. The header structure header is used to identify the start of a header structure,its size, and the number of data items it contains. Following the header structure header is anarea called the index.

The header structure's index is made up of zero or more index entries. Each entry is sixteen byteslong. The first four bytes contain a tag — a numeric value that identifies what type of data ispointed to by the entry. There are a large number of header tags defined in rpmtag.h. Here are afew of them:

typedef enum rpmTag_e { .... RPMTAG_NAME = 1000, /* s */ RPMTAG_VERSION = 1001, /* s */ RPMTAG_RELEASE = 1002, /* s */ RPMTAG_EPOCH = 1003, /* i */ RPMTAG_SUMMARY = 1004, /* s{} */ RPMTAG_DESCRIPTION = 1005, /* s{} */ RPMTAG_BUILDTIME = 1006, /* i */ RPMTAG_BUILDHOST = 1007, /* s */

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http://lwn.net/Articles/441085/



RPMTAG_INSTALLTIME = 1008, /* i */ RPMTAG_SIZE = 1009, /* i */ RPMTAG_DISTRIBUTION = 1010, /* s */ RPMTAG_VENDOR = 1011, /* s */ ..... /* tags 1997-4999 reserved */ RPMTAG_FILENAMES = 5000, /* s[] extension */ RPMTAG_FILEPROVIDE = 5001, /* s[] extension */ RPMTAG_FILEREQUIRE = 5002, /* s[] extension */ RPMTAG_FSNAMES = 5003, /* s[] (unimplemented) */ RPMTAG_FSSIZES = 5004, /* l[] (unimplemented) */ RPMTAG_TRIGGERCONDS = 5005, /* s[] extension */ RPMTAG_TRIGGERTYPE = 5006, /* s[] extension */ RPMTAG_ORIGFILENAMES = 5007, /* s[] extension */ RPMTAG_LONGFILESIZES = 5008, /* l[] */ RPMTAG_LONGSIZE = 5009, /* l */} rpmTag;

Following each tag, is a four-byte type, which is a numeric value that describes the format of thedata pointed to by the entry. Here is the current list of types defined in rpmtag.h:

typedef enum rpmTagType_e { RPM_NULL_TYPE = 0, RPM_CHAR_TYPE = 1, RPM_INT8_TYPE = 2, RPM_INT16_TYPE = 3, RPM_INT32_TYPE = 4, RPM_INT64_TYPE = 5, RPM_STRING_TYPE = 6, RPM_BIN_TYPE = 7, RPM_STRING_ARRAY_TYPE = 8, RPM_I18NSTRING_TYPE = 9,} rpmTagType;

Most of these types should be self explanatory. The difference between a STRING type and aSTRING_ARRAY type is that the former is a regular null terminated string whereas the latter is acollection of strings. RPM_I18NSTRING_TYPE is depreciated.

Next is a 4-byte offset value that contains the actual position of the data, relative to the beginningof the store. Finally, there is a four-byte count that contains the number of data items pointed toby the index entry. STRING data always has a count of 1, while STRING_ARRAY data has a countequal to the number of strings contained in the store.

After the index comes the store. It is in the store that actual data items are kept. The data in thestore is packed together as closely as possible in network byte order, i.e. most significant byte first.STRING data is terminated with a null byte. Integer data is stored at the natural boundary for itstype, i.e. a 32-bit integer is stored on an 4-byte boundary.

Okay, time to talk about how to programmatically access RPM packages. However before youstart using the RPM library, you need to figure out what version of the RPM library you are using.If you are writing a shell script, this is easy to do. For example on Fedora 15:

$ /usr/lib/rpm/rpmdeps --versionRPM version 4.9.0

The RPM library from rpm5.org has the rpmlibVersion API which can be used to retrieve thelibrary version or you can simply access the RPMVERSION string as shown below.

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#include <stdio.h>#include <rpm/rpmlib.h>intmain(){ fprintf(stderr, "RPM Version: %s\n", RPMVERSION);}

Unfortunately the RPM library from rpm.org does not have anything similar. Note to rpm.orgdevelopers! Please add the rpmlibVersion API to your list of supported public APIs so thatapplications that need to programmatically access RPM packages and databases can easily figureout which flavor and release of an RPM library they are dealing with and adjust their codeaccordingly.

On Fedora 15, the version string that is returned is 4.9.0 which indicates a version of RPM thatwas released in March 2011. On CentOS 5.6, the version string that is returned is 4.4.2.3 whichindicates a significantly older version of RPM released in April 2008. There are significant andmajor differences between these versions. In particular C code written for one of these twoparticular RPM versions will probably not work for the other version without modification.

It gets worse, by the way, as Fedora 15 and Red Hat Enterprise Linux 6 use the newer RPMlibrary which also includes a new format and SHA hash. This causes problems when you try toinstall an RPM built on one of these platforms on an older platform such as CentOS 5.6 which doesnot know about the new format and hash. As a result, CentOS 5.6 will complain that it cannotconfirm the integrity of the RPM package.

You also need to be able to determine what features a particular version of RPM supports. Here isone way of doing it:

#include <stdio.h>#include <stdlib.h>#include <rpm/rpmlib.h>#include <rpm/rpmds.h>intmain(int argc, char *argv[]){ const char *DNEVR; rpmds ds = NULL; int rc; rpmReadConfigFiles(NULL, NULL); rc = rpmdsRpmlib(&ds, NULL); ds = rpmdsInit(ds); fprintf(stdout, "Supported features:\n"); while (rpmdsNext(ds) >= 0) { if ((DNEVR = rpmdsDNEVR(ds)) != NULL) fprintf(stdout, "%s\n", DNEVR + 2); } ds = rpmdsFree(ds); exit(0);}

You have to have the RPM development package (rpm-devel) installed in order to be able tocompile the above code.

This code simply prints out the supported RPM feature set. Here is what is outputted for the RPMlibrary on Fedora 15:

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ttp://en.wikipedia.org/wiki/Secure_Hash_Algorithm


Supported features:rpmlib(BuiltinLuaScripts) = 4.2.2-1rpmlib(CompressedFileNames) = 3.0.4-1rpmlib(ConcurrentAccess) = 4.1-1rpmlib(ExplicitPackageProvide) = 4.0-1rpmlib(FileCaps) = 4.6.1-1rpmlib(FileDigests) = 4.6.0-1rpmlib(HeaderLoadSortsTags) = 4.0.1-1rpmlib(PartialHardlinkSets) = 4.0.4-1rpmlib(PayloadFilesHavePrefix) = 4.0-1rpmlib(PayloadIsBzip2) = 3.0.5-1rpmlib(PayloadIsLzma) = 4.4.2-1rpmlib(PayloadIsXz) = 5.2-1rpmlib(ScriptletExpansion) = 4.9.0-1rpmlib(ScriptletInterpreterArgs) = 4.0.3-1rpmlib(VersionedDependencies) = 3.0.3-1

By the way, there is draft documentation for an RPM Guide on the Fedora Project website. I do notknow when this guide was produced (probably 2003) but the latest copyright notice includes 2010.I cannot speak for the rest of this guide but the chapters on Programming RPM with C andProgramming RPM with Python are frankly rubbish and downright misleading.

For example, listing 16-1 (rpm1.c), shown below, will not even compile on Fedora 15 or even onCentos 5.6 which has a far older version of RPM.

#include <stdio.h>#include <stdlib.h>#include <rpmlib.h>intmain(int argc, char * argv[]){ int status = rpmReadConfigFiles( (const char*) NULL, (const char*) NULL); if (status != 0) { printf("Error reading RC files.\n"); exit(-1); } else { printf("Read RC OK\n"); } rpmSetVerbosity(RPMMESS_NORMAL); rpmShowRC( stdout ); exit(0);}

The listing is not even pretty formatted in the guide. The above formatting is all mine. TheRPMMESS_* defines were removed way back in 2007. As an aside, where did the convention touse exit(-1) come from? That looks more like something from the Microsoft Windows world! Thecompilation instructions are also wierd.

$ cc -I/usr/include/rpm -o rpm1 rpm1.c -lrpm -lrpmdb -lrpmio –lpopt

Why the need to reference lrpmdb and libpopt? No routines from either of these libraries are usedin the above code.

Here is the above example rewritten to work on Fedora 15:

#include <stdio.h>

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http://docs.fedoraproject.org/en-US/Fedora_Draft_Documentation/0.1/html/RPM_Guide/index.html

http://docs.fedoraproject.org/en-US/Fedora_Draft_Documentation/0.1/html/RPM_Guide/ch-programming-c.html

http://docs.fedoraproject.org/en-US/Fedora_Draft_Documentation/0.1/html/RPM_Guide/ch-rpm-programming-python.html


#include <stdlib.h>#include <rpm/rpmlib.h>#include <rpm/rpmlog.h>intmain(int argc, char * argv[]){ int status; if ((status = rpmReadConfigFiles( (const char*) NULL, (const char*) NULL))) { printf("ERROR: reading RC files\n"); exit(1); } rpmSetVerbosity(RPMLOG_NOTICE); rpmShowRC(stdout); exit(0);}

You can compile the above code using gcc -o rpm1 rpm1.c -lrpm -lrpmio.

The following example shows the way that you will traditionally see being used to generate a listof the installed RPM packages on a system if you do a search for such code on the Internet.

#include <stdio.h>#include <stdlib.h>#include <string.h>#include <fcntl.h>#include <unistd.h>#include <rpm/rpmlib.h>#include <rpm/header.h>#include <rpm/rpmdb.h>intmain(int argc, char *argv[]){ rpmdbMatchIterator mi; int type, count; char *name; rpmdb db; Header h; rpmReadConfigFiles( NULL, NULL ); if (rpmdbOpen( "", &db, O_RDONLY, 0644 ) != 0) { fprintf( stderr, "ERROR: Cannot open RPM database\n"); exit(1); } mi = rpmdbInitIterator(db, RPMDBI_PACKAGES, NULL, 0); while ((h = rpmdbNextIterator(mi))) { headerGetEntry(h, RPMTAG_NAME, &type, (void **) &name, &count); printf("%s\n", name); } rpmdbFreeIterator(mi); rpmdbClose(db); exit(0);}

It uses rpmdbOpen and rpmdbClose to open and close the RPM database, and arpmdbMatchInterator to iterate through the RPM database looking for matching entries forRPMTAG_NAME.

This works for CentOS 5.6 but is not supported in Fedora 15. In RPM 4.9.0, almost all low-levelrpmdb manipulation functions including the rpmdbOpen, rpmdbClose and rpmdbMatchInteratorroutines used above were removed or internalized. See the RPM 4.9.0 Release Notes for fulldetails.

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http://rpm.org/wiki/Realeases/4.9.0/


The following example works on Fedora 15 and outputs a list of the name (RPMTAG_NAME) andsize (RPMTAG_SIZE) of each installed package.

#include <stdio.h>#include <stdlib.h>#include <rpm/rpmlib.h>#include <rpm/header.h>#include <rpm/rpmts.h>#include <rpm/rpmdb.h>intmain(){ rpmts ts = NULL; Header h; rpmdbMatchIterator mi; rpmtd td, tn; char time_buffer[512]; int rc1, rc2; td = rpmtdNew(); tn = rpmtdNew(); ts = rpmtsCreate(); rpmReadConfigFiles( NULL, NULL ); mi = rpmtsInitIterator( ts, RPMDBI_PACKAGES, NULL, 0); while (NULL != (h = rpmdbNextIterator(mi))) { h = headerLink(h); rc1 = headerGet(h, RPMTAG_NAME, tn, HEADERGET_EXT); rc2 = headerGet(h, RPMTAG_SIZE, td, HEADERGET_EXT); // output installed package name and size fprintf(stdout, "%s (%llu)\n", rpmtdGetString(tn), rpmtdGetNumber(td)); rpmtdReset(td); rpmtdReset(tn); headerFree(h); } rpmdbFreeIterator(mi); rpmtsFree(ts); exit(0);}

The following example shows how to print out more information about of the installed packages onyour system.

#include <stdio.h>#include <stdlib.h>#include <rpm/rpmlib.h>#include <rpm/header.h>#include <rpm/rpmts.h>#include <rpm/rpmdb.h>intmain(int argc, char *argv[]){ rpmts ts = NULL; Header h; rpmdbMatchIterator mi; char *n, *v, *r, *g, *a; ts = rpmtsCreate(); rpmReadConfigFiles( NULL, NULL ); mi = rpmtsInitIterator( ts, RPMDBI_PACKAGES, NULL, 0); while (NULL != (h = rpmdbNextIterator(mi))) { h = headerLink( h ); headerGetEntry( h, RPMTAG_NAME, NULL, (void**)&n, NULL); headerGetEntry( h, RPMTAG_VERSION, NULL, (void**)&v, NULL); headerGetEntry( h, RPMTAG_RELEASE, NULL, (void**)&r, NULL); headerGetEntry( h, RPMTAG_GROUP, NULL, (void**)&g, NULL);

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headerGetEntry( h, RPMTAG_ARCH, NULL, (void**)&a, NULL); fprintf(stdout, "%s-%s-%s.%s\n", n, v, r, a); headerFree(h); } rpmdbFreeIterator(mi); rpmtsFree(ts); exit(0);}

This example works on both CentOS 5.6 and Fedora 15. Here is some sample output:

iso-codes-0.53-1.noarchzlib-1.2.3-3.x86_64libstdc++-4.1.2-50.el5.x86_64db4-4.3.29-10.el5_5.2.x86_64info-4.8-14.el5.x86_64gawk-3.1.5-14.el5.x86_64libgcrypt-1.4.4-5.el5.x86_64libfontenc-1.0.2-2.2.el5.x86_64libieee1284-0.2.9-4.el5.x86_64grep-2.5.1-55.el5.x86_64....

By the way, RPM has Python, Perl and Lua support. Here is the equivalent code written in Python:

#!/usr/bin/pythonimport rpmts=rpm.ts()mi=ts.dbMatch()for hdr in mi: print "%s-%s-%s.%s" % (hdr['name'], hdr['version'], hdr['release'], hdr['arch'])

As you can see Python can greatly simplify things when you wish to work with RPM packages.

The following example demonstrates how to print out a number of tags in XML format for eachinstalled package.

#include <stdio.h>#include <stdlib.h>#include <string.h>#include <inttypes.h>#include <rpm/rpmlib.h>#include <rpm/header.h>#include <rpm/rpmts.h>#include <rpm/rpmdb.h>struct tag { int tagno; char *element;};truct tag tags[] = { { RPMTAG_NAME, "Name"}, { RPMTAG_VERSION, "Version" }, { RPMTAG_RELEASE, "Release" }, { RPMTAG_SUMMARY, "Summary" }, { RPMTAG_BUILDTIME, "BuildTime"}, { RPMTAG_BUILDHOST, "BuildHost" }, { RPMTAG_INSTALLTIME, "InstallTime" }, { RPMTAG_SIZE, "Size" }, { RPMTAG_LICENSE, "License"},

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http://blog.fpmurphy.com/www.lua.org


{ RPMTAG_URL, "SourceUrl" }, { RPMTAG_PAYLOADFORMAT, "PayloadFormat" }, { RPMTAG_PAYLOADCOMPRESSOR, "PayloadCompressor" }};#define NTAGS (sizeof(tags)/sizeof(struct tag))intmain(int argc, char *argv[]){ rpmdbMatchIterator mi; rpmts ts = NULL; rpmtd td; Header h; int i; td = rpmtdNew(); ts = rpmtsCreate(); rpmReadConfigFiles(NULL, NULL); printf("<InstalledPackages>\n"); mi = rpmtsInitIterator( ts, RPMDBI_PACKAGES, NULL, 0); while (NULL != (h = rpmdbNextIterator(mi))) { h = headerLink(h); printf(" <Package>\n"); for ( i = 0; i < NTAGS; i++) { headerGet(h, (rpm_tag_t)tags[i].tagno, td, HEADERGET_ALLOC | HEADERGET_EXT); if (td->data) { switch(td->type) { case RPM_NULL_TYPE: break; case RPM_CHAR_TYPE: printf(" <%s>%s</%s>\n", tags[i].element, td->data, tags[i].element); break; case RPM_INT8_TYPE: case RPM_INT16_TYPE: printf(" <%s>%d</%s>\n", tags[i].element, td->data, tags[i].element); break; case RPM_INT32_TYPE: if ((tags[i].tagno == RPMTAG_BUILDTIME) || (tags[i].tagno == RPMTAG_INSTALLTIME)) { printf(" <%s>%s</%s>\n", tags[i].element, rpmtdFormat(td, RPMTD_FORMAT_DATE , NULL), tags[i].element); } else if (tags[i].tagno == RPMTAG_SIZE) { printf(" <%s>%" PRIu64 "<%s>\n", tags[i].element, rpmtdGetNumber(td), tags[i].element); } else { printf(" <%s>%u</%s>\n", tags[i].element, td->data, tags[i].element); } break; case RPM_INT64_TYPE: printf(" <%s>%" PRIu64 "</%s>\n", tags[i].element, rpmtdGetNumber(td), tags[i].element); break; case RPM_STRING_TYPE: printf(" <%s>%s</%s>\n", tags[i].element, rpmtdGetString(td), tags[i].element); break; case RPM_BIN_TYPE: printf(" <%s>%x</%s>\n", tags[i].element, td->data, tags[i].element); break; case RPM_STRING_ARRAY_TYPE: default: break; } } rpmtdReset(td); }

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headerFree(h); printf(" </Package>\n"); } printf("</InstalledPackages>\n"); rpmdbFreeIterator(mi); rpmtsFree(ts); exit(0);}

This works on Fedora 15. Here is example output:

<InstalledPackages> <Package> <Name>file-roller</Name> <Version>3.0.2</Version> <Release>1.fc15</Release> <Summary>Tool for viewing and creating archives</Summary> <BuildTime>Wed May 25 19:57:10 2011</BuildTime> <BuildHost>x86-06.phx2.fedoraproject.org</BuildHost> <InstallTime>Thu Jun 2 17:45:29 2011</InstallTime> <Size>5928015<Size> <License>GPLv2+</License> <SourceUrl>http://download.gnome.org/sources/file-roller/</SourceUrl> <PayloadFormat>cpio</PayloadFormat> <PayloadCompressor>xz</PayloadCompressor> </Package> <Package> <Name>expect</Name> <Version>5.45</Version> <Release>3.fc15</Release> <Summary>A program-script interaction and testing utility</Summary> <BuildTime>Wed Mar 16 09:58:49 2011</BuildTime> <BuildHost>x86-12.phx2.fedoraproject.org</BuildHost> <InstallTime>Mon Jun 13 10:24:25 2011</InstallTime> <Size>559676<Size> <License>Public Domain</License> <SourceUrl>http://expect.nist.gov/</SourceUrl> <PayloadFormat>cpio</PayloadFormat> <PayloadCompressor>xz</PayloadCompressor> </Package> ..... <Package> <Name>libxkbfile-devel</Name> <Version>1.0.7</Version> <Release>2.fc15</Release> <Summary>X.Org X11 libxkbfile development package</Summary> <BuildTime>Tue Feb 8 08:03:57 2011</BuildTime> <BuildHost>x86-13.phx2.fedoraproject.org</BuildHost> <InstallTime>Thu Jun 2 17:56:48 2011</InstallTime> <Size>38055<Size> <License>MIT</License> <SourceUrl>http://www.x.org</SourceUrl> <PayloadFormat>cpio</PayloadFormat> <PayloadCompressor>xz</PayloadCompressor> </Package></InstalledPackages>

Note that the version of RPM on CentOS 5.6 does not support RPM_INT64_TYPE. As a result datesand suchlike are stored in a RPM_INT32_TYPE.

Turning now to how to examine individual RPM packages. The following simple example show youhow to query a package file:

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#include <stdio.h>#include <stdlib.h>#include <rpm/rpmlib.h>#include <rpm/header.h>#include <rpm/rpmts.h>#include <rpm/rpmdb.h>#include <rpm/rpmlog.h>intmain(int argc, char *argv[]){ int i; rpmts ts; FD_t fd; rpmRC rc; Header hdr; char *pkg_name, *pkg_version, *pkg_release; rpmVSFlags vsflags = 0; rc = rpmReadConfigFiles(NULL, NULL); if (rc != RPMRC_OK) { rpmlog(RPMLOG_NOTICE, "Unable to read RPM configuration.\n"); exit(1); } fd = Fopen(argv[1], "r.ufdio"); if ((!fd) || Ferror(fd)) { rpmlog(RPMLOG_NOTICE, "Failed to open package file (%s)\n", Fstrerror(fd)); if (fd) { Fclose(fd); } exit(1); } ts = rpmtsCreate(); vsflags |= _RPMVSF_NODIGESTS; vsflags |= _RPMVSF_NOSIGNATURES; vsflags |= RPMVSF_NOHDRCHK; (void) rpmtsSetVSFlags(ts, vsflags); rc = rpmReadPackageFile(ts, fd, argv[1], &hdr); if (rc != RPMRC_OK) { rpmlog(RPMLOG_NOTICE, "Could not read package file\n"); Fclose(fd); exit(1); } Fclose(fd); if (headerNVR(hdr, (const char **) &pkg_name, (const char **) &pkg_version, (const char **) &pkg_release)) { rpmlog(RPMLOG_NOTICE, "Header read failed\n"); } else { printf("Package is: %s-%s-%s\n", pkg_name, pkg_version, pkg_release); headerFreeData(pkg_name, RPM_STRING_TYPE); headerFreeData(pkg_version, RPM_STRING_TYPE); headerFreeData(pkg_release, RPM_STRING_TYPE); } headerFree(hdr); rpmtsFree(ts); exit(0);}

You can compile the above example using gcc -o example example.c -lrpm -lrpmio. This compileswith no errors or warnings on CentOS 5.6 but issues a warning that headerNVR is depreciated onFedora 15.

Suppose you want to find out the list of requirements a particular installed RPM package has. Oneway is to use rpm -qR . Another way is to use find-requires or rpmdeps as shown below:

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$ rpm -ql rpm-devel | /usr/lib/rpm/find-requireslibacl.so.1()(64bit)libbz2.so.1()(64bit)libcap.so.2()(64bit)libc.so.6()(64bit)libc.so.6(GLIBC_2.14)(64bit)libc.so.6(GLIBC_2.2.5)(64bit)libc.so.6(GLIBC_2.3.4)(64bit)libdb-4.8.so()(64bit)libdl.so.2()(64bit)libelf.so.1()(64bit)liblua-5.1.so()(64bit)liblzma.so.5()(64bit)libm.so.6()(64bit)libnss3.so()(64bit)libpopt.so.0()(64bit)libpthread.so.0()(64bit)librpmio.so.2()(64bit)librpm.so.2()(64bit)librt.so.1()(64bit)libselinux.so.1()(64bit)libz.so.1()(64bit)

$ rpm -ql rpm-devel | /usr/lib/rpm/rpmdeps -R/usr/bin/pkg-configlibacl.so.1()(64bit)libbz2.so.1()(64bit)libc.so.6()(64bit)libc.so.6(GLIBC_2.14)(64bit)libc.so.6(GLIBC_2.2.5)(64bit)libc.so.6(GLIBC_2.3.4)(64bit)libcap.so.2()(64bit)libdb-4.8.so()(64bit)libdl.so.2()(64bit)libelf.so.1()(64bit)liblua-5.1.so()(64bit)liblzma.so.5()(64bit)libm.so.6()(64bit)libnss3.so()(64bit)libpopt.so.0()(64bit)libpopt.so.0(LIBPOPT_0)(64bit)libpthread.so.0()(64bit)librpm.so.2()(64bit)librpmbuild.so.2()(64bit)librpmio.so.2()(64bit)librpmsign.so.0()(64bit)librt.so.1()(64bit)libselinux.so.1()(64bit)libz.so.1()(64bit)rtld(GNU_HASH)

Here is an example of a C program that will print out the equivalent information together withinstalled files, conflicts and obsoletes:

#include <stdio.h>#include <stdlib.h>#include <rpm/rpmlib.h>#include <rpm/rpmds.h>#include <rpm/rpmts.h>#include <rpm/rpmdb.h>intmain(int argc, char *argv[]){ const char *DNEVR;

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rpmdbMatchIterator mi; rpmds ds = NULL; Header h; rpmtd td_name, td_version, td_release, td_size, td_group, td_installtime; rpmts ts = NULL; rpmfi fi; if (argc != 2) { fprintf(stderr, "ERROR: No RPM specified on command line.\n"); exit(1); } td_name = rpmtdNew(); td_version = rpmtdNew(); td_release = rpmtdNew(); td_size = rpmtdNew(); td_group = rpmtdNew(); td_installtime = rpmtdNew(); ts = rpmtsCreate(); rpmReadConfigFiles(NULL, NULL); mi = rpmtsInitIterator(ts, RPMTAG_NAME, argv[1], 0); if (NULL != (h = rpmdbNextIterator(mi))) { h = headerLink(h); headerGet(h, RPMTAG_NAME, td_name, HEADERGET_EXT); headerGet(h, RPMTAG_VERSION, td_version, HEADERGET_EXT); headerGet(h, RPMTAG_RELEASE, td_release, HEADERGET_EXT); headerGet(h, RPMTAG_SIZE, td_size, HEADERGET_EXT); headerGet(h, RPMTAG_GROUP, td_group, HEADERGET_EXT); headerGet(h, RPMTAG_INSTALLTIME, td_installtime, HEADERGET_EXT); printf("%-20s: %s-%s-%s\n", "Package", rpmtdGetString(td_name), rpmtdGetString(td_version), rpmtdGetString(td_release)); printf("%-20s: %s\n", "Group", rpmtdGetString(td_group)); printf("%-20s: %llu\n", "Size", rpmtdGetNumber(td_size)); printf("%-20s: %s\n", "Installed on", rpmtdFormat(td_installtime, RPMTD_FORMAT_DATE, NULL)); fi = rpmfiNew(NULL, h, RPMTAG_BASENAMES, RPMFI_KEEPHEADER); if (fi) { fprintf(stdout, "\nFiles Provided:\n"); while (rpmfiNext(fi) != -1) fprintf(stdout, " %s\n", rpmfiFN(fi)); fi = rpmfiFree(fi); }#if EXTRA ds = rpmdsNew(h, RPMTAG_PROVIDENAME, 0); if (ds) { fprintf(stdout, "\nProvides:\n"); while (rpmdsNext(ds) >= 0) { if ((DNEVR = rpmdsDNEVR(ds)) != NULL) fprintf(stdout, " %s\n", DNEVR + 1); } ds = rpmdsFree(ds); }#endif ds = rpmdsNew(h, RPMTAG_REQUIRENAME, 0); if (ds) { fprintf(stdout, "\nRequires:\n"); while (rpmdsNext(ds) >= 0) { if ((DNEVR = rpmdsDNEVR(ds)) != NULL) fprintf(stdout, " %s\n", DNEVR + 1); } ds = rpmdsFree(ds); } ds = rpmdsNew(h, RPMTAG_OBSOLETENAME, 0); if (ds) { fprintf(stdout, "\nObsoletes:\n"); while (rpmdsNext(ds) >= 0) { if ((DNEVR = rpmdsDNEVR(ds)) != NULL) fprintf(stdout, " %s\n", DNEVR + 1); } ds = rpmdsFree(ds);

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} ds = rpmdsNew(h, RPMTAG_CONFLICTNAME, 0); if (ds) { fprintf(stdout, "\nConflicts:\n"); while (rpmdsNext(ds) >= 0) { if ((DNEVR = rpmdsDNEVR(ds)) != NULL) fprintf(stdout, " %s\n", DNEVR + 1); } ds = rpmdsFree(ds); } headerFree(h); } rpmdbFreeIterator(mi); rpmtsFree(ts); exit(0);}

This works on Fedora 15 but not on CentOS 5.6. However, it is relatively easy to modify to get it towork on CentOS 5.6 and thus I will leave that as an exercise for you. The main changes relate tothe use of the rpmtd type. These need to be eliminated as the version of RPM on CentOS 5.6 doesnot support the rpmtd type.

Here is what is outputted for the xorg-x11-xkb-utils package:

./rpminfo.py xorg-x11-xkb-utilsPackage : xorg-x11-xkb-utils-7.5-3.fc15Group : User Interface/XSize : 199629Installed on : Thu Jun 2 17:39:31 2011

Files Provided: /usr/bin/setxkbmap /usr/bin/xkbcomp /usr/share/man/man1/setxkbmap.1.gz /usr/share/man/man1/xkbcomp.1.gz

Requires: libX11.so.6()(64bit) libc.so.6()(64bit) libc.so.6(GLIBC_2.2.5)(64bit) libc.so.6(GLIBC_2.3)(64bit) libc.so.6(GLIBC_2.3.4)(64bit) libc.so.6(GLIBC_2.4)(64bit) libc.so.6(GLIBC_2.7)(64bit) libxkbfile.so.1()(64bit) rpmlib(CompressedFileNames) <= 3.0.4-1rpmlib(FileDigests) <= 4.6.0-1rpmlib(PayloadFilesHavePrefix) <= 4.0-1rtld(GNU_HASH)rpmlib(PayloadIsXz) <= 5.2-1

Obsoletes:XFree86xorg-x11

Here is how to do the same thing using Python. It is loosely based on the example given in listing17-3 in the Fedora Project RPM Guide which by the way, does not work nor, I suspect, everworked! The output produced by this script is somewhat more comprehensive than that of the Cversion even though the script has fewer lines of code.

#!/usr/bin/python

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import rpm, sysdef stringfromds(ds): retlist=[] for dataset in ds: t=dataset[0] values=t.split(" ")[1:] retlist.append(" ".join(values)) return retlistdef printEntry(header, label, format, extra): value = header.sprintf(format).strip() print "%-20s: %s %s" % (label, value, extra)def printHeader(h): if h[rpm.RPMTAG_SOURCEPACKAGE]: extra = " source package" else: extra = " binary package" printEntry(h, 'Package', "%{NAME}-%{VERSION}-%{RELEASE}", extra) printEntry(h, 'Group', "%{GROUP}", '') printEntry(h, 'Summary', "%{Summary}", '') printEntry(h, 'Arch-OS-Platform', "%{ARCH}-%{OS}-%{PLATFORM}", '') printEntry(h, 'Vendor', "%{Vendor}", '') printEntry(h, 'URL', "%{URL}", '') printEntry(h, 'Size', "%{Size}", '') printEntry(h, 'Installed on', "%{INSTALLTID:date}", '') print "%-20s: %s" % ("Description", h['Description']) print "\nFiles Provided:" for fi in h.fiFromHeader(): print " ", fi[0], " ", fi[1], " ", fi[12] ds = rpm.ds(h, 'requires') if ds: print "\nRequires:" for d in stringfromds(ds): print " ", d ds = rpm.ds(h, 'obsoletes') if ds: print "\nObsoletes:" for d in stringfromds(ds): print " ", d ds = rpm.ds(h, 'conflicts') if ds: print "\nConflicts:" for d in stringfromds(ds): print " ", ddef main(argv): ts = rpm.TransactionSet() for h in ts.dbMatch( 'name', argv[1]): printHeader(h)if __name__ == "__main__": if len(sys.argv) == 1: print "ERROR: No RPM specified on command line." sys.exit(1) else: main(sys.argv)

Here is what is outputted for the xorg-x11-xkb-utils package:

$ ./rpminfo.py xorg-x11-xkb-utilsPackage : xorg-x11-xkb-utils-7.5-3.fc15 binary packageGroup : User Interface/XSummary : X.Org X11 xkb utilitiesArch-OS-Platform : x86_64-linux-x86_64-redhat-linux-gnuVendor : Fedora ProjectURL : http://www.x.orgSize : 199629Installed on : Thu Jun 2 17:38:11 2011

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Description : X.Org X11 xkb core utilities

Files Provided: /usr/bin/setxkbmap 19224 e5e5757d15ca331474c43a0319d0307920fb17b3ed9d04c041e13b56c4aa08e4 /usr/bin/xkbcomp 176960 e6b265d05cd6432859d7a24fb8f6d6ccec3cbd668abd54afd9606322d3dd9a9e /usr/share/man/man1/setxkbmap.1.gz 1753 4a91c43a425699e4209880cf80a28eeae565763ece6cffaa8308a92139fd3250 /usr/share/man/man1/xkbcomp.1.gz 1692 29d16f6c864bf62b7f3e3e0400e121def3f85e6d64676dffb6d92c54503a0c76

Requires: libX11.so.6()(64bit) libc.so.6()(64bit) libc.so.6(GLIBC_2.2.5)(64bit) libc.so.6(GLIBC_2.3)(64bit) libc.so.6(GLIBC_2.3.4)(64bit) libc.so.6(GLIBC_2.4)(64bit) libc.so.6(GLIBC_2.7)(64bit) libxkbfile.so.1()(64bit) rpmlib(CompressedFileNames) <= 3.0.4-1rpmlib(FileDigests) <= 4.6.0-1rpmlib(PayloadFilesHavePrefix) <= 4.0-1rtld(GNU_HASH)rpmlib(PayloadIsXz) <= 5.2-1

Obsoletes:XFree86xorg-x11

Once again, you can see it is far easier to use Python than C when working with RPM packageinternals.

Before I sign off on this post, I have to say that the Linux world does not need two differentdevelopment communities around RPM. Yes, competition between the two RPM developmentcommunities had lead to some improvements in the RPM Package Manager but it also has lead towell known documented APIs such as rpmdbOpen and rpmdbClose being removed in recentreleases. These two communities should bury the ax and merge their efforts. Sometimes forkingcommunity projects is good and leads to really useful innovation. In this case it is my opinion thatit is not!

I also have to say that the documentation for using the RPM library APIs is frankly atrocious andboth RPM developer communities seems to make no serious attempt to inform users of theirlibraries of major changes in APIs other than obscure references to the changes in their respectiverelease notes. This needs to be corrected. A step in the right direction would be to provide simpleexamples of API usage when a new API is introduced or an old API removed.

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programmatically retrieve rpm package details

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