1dpkg-shlibdeps(1) dpkg suite dpkg-shlibdeps(1)
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6 dpkg-shlibdeps - generate shared library substvar dependencies
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9 dpkg-shlibdeps [option...] [-e] executable [option...]
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12 dpkg-shlibdeps calculates shared library dependencies for executables
13 named in its arguments. The dependencies are added to the substitution
14 variables file debian/substvars as variable names shlibs:dependency-
15 field where dependency-field is a dependency field name. Any other
16 variables starting with shlibs: are removed from the file.
17 dpkg-shlibdeps has two possible sources of information to generate
19 dependency information. Either symbols files or shlibs files. For each
20 binary that dpkg-shlibdeps analyzes, it finds out the list of libraries
21 that it's linked with. Then, for each library, it looks up either the
22 symbols file, or the shlibs file (if the former doesn't exist or if
23 debian/shlibs.local contains the relevant dependency). Both files are
24 supposed to be provided by the library package and should thus be
25 available as /var/lib/dpkg/info/package.symbols or
26 /var/lib/dpkg/info/package.shlibs. The package name is identified in
27 two steps: find the library file on the system (looking in the same
28 directories that ld.so would use), then use dpkg -S library-file to
29 lookup the package providing the library.
30 Symbols files
32 Symbols files contain finer-grained dependency information by providing
33 the minimum dependency for each symbol that the library exports. The
34 script tries to find a symbols file associated to a library package in
35 the following places (first match is used):
36 debian/*/DEBIAN/symbols
38 Shared library information generated by the current build process
39 that also invoked dpkg-shlibdeps. They are generated by dpkg-
40 gensymbols(1). They are only used if the library is found in a
41 package's build tree. The symbols file in that build tree takes
42 precedence over symbols files from other binary packages.
43 /etc/dpkg/symbols/package.symbols.arch
45 /etc/dpkg/symbols/package.symbols
46 Per-system overriding shared library dependency information. arch
47 is the architecture of the current system (obtained by dpkg-
48 architecture -qDEB_HOST_ARCH).
49 Output from “dpkg-query --control-path package symbols”
51 Package-provided shared library dependency information. Unless
52 overridden by --admindir, those files are located in /var/lib/dpkg.
53 While scanning the symbols used by all binaries, dpkg-shlibdeps
55 remembers the (biggest) minimal version needed for each library. At the
56 end of the process, it is able to write out the minimal dependency for
57 every library used (provided that the information of the symbols files
58 are accurate).
59 As a safe-guard measure, a symbols file can provide a Build-Depends-
61 Package meta-information field and dpkg-shlibdeps will extract the
62 minimal version required by the corresponding package in the Build-
63 Depends field and use this version if it's higher than the minimal
64 version computed by scanning symbols.
65 Shlibs files
67 Shlibs files associate directly a library to a dependency (without
68 looking at the symbols). It's thus often stronger than really needed
69 but very safe and easy to handle.
70 The dependencies for a library are looked up in several places. The
72 first file providing information for the library of interest is used:
73 debian/shlibs.local
75 Package-local overriding shared library dependency information.
76 /etc/dpkg/shlibs.override
78 Per-system overriding shared library dependency information.
79 debian/*/DEBIAN/shlibs
81 Shared library information generated by the current build process
82 that also invoked dpkg-shlibdeps. They are only used if the
83 library is found in a package's build tree. The shlibs file in that
84 build tree takes precedence over shlibs files from other binary
85 packages.
86 Output from “dpkg-query --control-path package shlibs”
88 Package-provided shared library dependency information. Unless
89 overridden by --admindir, those files are located in /var/lib/dpkg.
90 /etc/dpkg/shlibs.default
92 Per-system default shared library dependency information.
93 The extracted dependencies are then directly used (except if they are
95 filtered out because they have been identified as duplicate, or as
96 weaker than another dependency).
97
99 dpkg-shlibdeps interprets non-option arguments as executable names,
100 just as if they'd been supplied as -eexecutable.
101 -eexecutable
103 Include dependencies appropriate for the shared libraries required
104 by executable. This option can be used multiple times.
105 -ldirectory
107 Prepend directory to the list of directories to search for private
108 shared libraries (since dpkg 1.17.0). This option can be used
109 multiple times.
110 Note: Use this option instead of setting LD_LIBRARY_PATH, as that
112 environment variable is used to control the run-time linker and
113 abusing it to set the shared library paths at build-time can be
114 problematic when cross-compiling for example.
115 -ddependency-field
117 Add dependencies to be added to the control file dependency field
118 dependency-field. (The dependencies for this field are placed in
119 the variable shlibs:dependency-field.)
120 The -ddependency-field option takes effect for all executables
122 after the option, until the next -ddependency-field. The default
123 dependency-field is Depends.
124 If the same dependency entry (or set of alternatives) appears in
126 more than one of the recognized dependency field names Pre-Depends,
127 Depends, Recommends, Enhances or Suggests then dpkg-shlibdeps will
128 automatically remove the dependency from all fields except the one
129 representing the most important dependencies.
130 -pvarname-prefix
132 Start substitution variables with varname-prefix: instead of
133 shlibs:. Likewise, any existing substitution variables starting
134 with varname-prefix: (rather than shlibs:) are removed from the
135 substitution variables file.
136 -O[filename]
138 Print substitution variable settings to standard output (or
139 filename if specified, since dpkg 1.17.2), rather than being added
140 to the substitution variables file (debian/substvars by default).
141 -ttype
143 Prefer shared library dependency information tagged for the given
144 package type. If no tagged information is available, falls back to
145 untagged information. The default package type is deb. Shared
146 library dependency information is tagged for a given type by
147 prefixing it with the name of the type, a colon, and whitespace.
148 -Llocal-shlibs-file
150 Read overriding shared library dependency information from local-
151 shlibs-file instead of debian/shlibs.local.
152 -Tsubstvars-file
154 Write substitution variables in substvars-file; the default is
155 debian/substvars.
156 -v Enable verbose mode (since dpkg 1.14.8). Numerous messages are
158 displayed to explain what dpkg-shlibdeps does.
159 -xpackage
161 Exclude the package from the generated dependencies (since dpkg
162 1.14.8). This is useful to avoid self-dependencies for packages
163 which provide ELF binaries (executables or library plugins) using a
164 library contained in the same package. This option can be used
165 multiple times to exclude several packages.
166 -Spackage-build-dir
168 Look into package-build-dir first when trying to find a library
169 (since dpkg 1.14.15). This is useful when the source package
170 builds multiple flavors of the same library and you want to ensure
171 that you get the dependency from a given binary package. You can
172 use this option multiple times: directories will be tried in the
173 same order before directories of other binary packages.
174 -Ipackage-build-dir
176 Ignore package-build-dir when looking for shlibs, symbols, and
177 shared library files (since dpkg 1.18.5). You can use this option
178 multiple times.
179 --ignore-missing-info
181 Do not fail if dependency information can't be found for a shared
182 library (since dpkg 1.14.8). Usage of this option is discouraged,
183 all libraries should provide dependency information (either with
184 shlibs files, or with symbols files) even if they are not yet used
185 by other packages.
186 --warnings=value
188 value is a bit field defining the set of warnings that can be
189 emitted by dpkg-shlibdeps (since dpkg 1.14.17). Bit 0 (value=1)
190 enables the warning “symbol sym used by binary found in none of the
191 libraries”, bit 1 (value=2) enables the warning “package could
192 avoid a useless dependency” and bit 2 (value=4) enables the warning
193 “binary should not be linked against library”. The default value
194 is 3: the first two warnings are active by default, the last one is
195 not. Set value to 7 if you want all warnings to be active.
196 --admindir=dir
198 Change the location of the dpkg database (since dpkg 1.14.0). The
199 default location is /var/lib/dpkg.
200 -?, --help
202 Show the usage message and exit.
203 --version
205 Show the version and exit.
206
208 DPKG_COLORS
209 Sets the color mode (since dpkg 1.18.5). The currently accepted
210 values are: auto (default), always and never.
211 DPKG_NLS
213 If set, it will be used to decide whether to activate Native
214 Language Support, also known as internationalization (or i18n)
215 support (since dpkg 1.19.0). The accepted values are: 0 and 1
216 (default).
217
219 Warnings
220 Since dpkg-shlibdeps analyzes the set of symbols used by each binary of
221 the generated package, it is able to emit warnings in several cases.
222 They inform you of things that can be improved in the package. In most
223 cases, those improvements concern the upstream sources directly. By
224 order of decreasing importance, here are the various warnings that you
225 can encounter:
226 symbol sym used by binary found in none of the libraries.
228 The indicated symbol has not been found in the libraries linked
229 with the binary. The binary is most likely a library and it needs
230 to be linked with an additional library during the build process
231 (option -llibrary of the linker).
232 binary contains an unresolvable reference to symbol sym: it's probably
234 a plugin
235 The indicated symbol has not been found in the libraries linked
236 with the binary. The binary is most likely a plugin and the symbol
237 is probably provided by the program that loads this plugin. In
238 theory a plugin doesn't have any SONAME but this binary does have
239 one and as such it could not be clearly identified as such. However
240 the fact that the binary is stored in a non-public directory is a
241 strong indication that's it's not a normal shared library. If the
242 binary is really a plugin, then disregard this warning. But there's
243 always the possibility that it's a real library and that programs
244 linking to it are using an RPATH so that the dynamic loader finds
245 it. In that case, the library is broken and needs to be fixed.
246 package could avoid a useless dependency if binary was not linked
248 against library (it uses none of the library's symbols)
249 None of the binaries that are linked with library use any of the
250 symbols provided by the library. By fixing all the binaries, you
251 would avoid the dependency associated to this library (unless the
252 same dependency is also generated by another library that is really
253 used).
254 package could avoid a useless dependency if binaries were not linked
256 against library (they use none of the library's symbols)
257 Exactly the same as the above warning, but for multiple binaries.
258 binary should not be linked against library (it uses none of the
260 library's symbols)
261 The binary is linked to a library that it doesn't need. It's not a
262 problem but some small performance improvements in binary load time
263 can be obtained by not linking this library to this binary. This
264 warning checks the same information as the previous one but does it
265 for each binary instead of doing the check globally on all binaries
266 analyzed.
267 Errors
269 dpkg-shlibdeps will fail if it can't find a public library used by a
270 binary or if this library has no associated dependency information
271 (either shlibs file or symbols file). A public library has a SONAME and
272 is versioned (libsomething.so.X). A private library (like a plugin)
273 should not have a SONAME and doesn't need to be versioned.
274 couldn't find library library-soname needed by binary (its RPATH is
276 'rpath')
277 The binary uses a library called library-soname but dpkg-shlibdeps
278 has been unable to find the library. dpkg-shlibdeps creates a list
279 of directories to check as following: directories listed in the
280 RPATH of the binary, directories added by the -l option,
281 directories listed in the LD_LIBRARY_PATH environment variable,
282 cross multiarch directories (ex. /lib/arm64-linux-gnu,
283 /usr/lib/arm64-linux-gnu), standard public directories (/lib,
284 /usr/lib), directories listed in /etc/ld.so.conf, and obsolete
285 multilib directories (/lib32, /usr/lib32, /lib64, /usr/lib64).
286 Then it checks those directories in the package's build tree of the
287 binary being analyzed, in the packages' build trees indicated with
288 the -S command-line option, in other packages' build trees that
289 contains a DEBIAN/shlibs or DEBIAN/symbols file and finally in the
290 root directory. If the library is not found in any of those
291 directories, then you get this error.
292 If the library not found is in a private directory of the same
294 package, then you want to add the directory with -l. If it's in
295 another binary package being built, you want to make sure that the
296 shlibs/symbols file of this package is already created and that -l
297 contains the appropriate directory if it also is in a private
298 directory.
299 no dependency information found for library-file (used by binary).
301 The library needed by binary has been found by dpkg-shlibdeps in
302 library-file but dpkg-shlibdeps has been unable to find any
303 dependency information for that library. To find out the
304 dependency, it has tried to map the library to a Debian package
305 with the help of dpkg -S library-file. Then it checked the
306 corresponding shlibs and symbols files in /var/lib/dpkg/info/, and
307 in the various package's build trees (debian/*/DEBIAN/).
308 This failure can be caused by a bad or missing shlibs or symbols
310 file in the package of the library. It might also happen if the
311 library is built within the same source package and if the shlibs
312 files has not yet been created (in which case you must fix
313 debian/rules to create the shlibs before calling dpkg-shlibdeps).
314 Bad RPATH can also lead to the library being found under a non-
315 canonical name (example:
316 /usr/lib/openoffice.org/../lib/libssl.so.0.9.8 instead of
317 /usr/lib/libssl.so.0.9.8) that's not associated to any package,
318 dpkg-shlibdeps tries to work around this by trying to fallback on a
319 canonical name (using realpath(3)) but it might not always work.
320 It's always best to clean up the RPATH of the binary to avoid
321 problems.
322 Calling dpkg-shlibdeps in verbose mode (-v) will provide much more
324 information about where it tried to find the dependency
325 information. This might be useful if you don't understand why it's
326 giving you this error.
327
329 deb-substvars(5), deb-shlibs(5), deb-symbols(5), dpkg-gensymbols(1).
3301.21.9 2022-07-01 dpkg-shlibdeps(1)