DEBUGINFOD-FIND(1) General Commands Manual DEBUGINFOD-FIND(1)
NAME
debuginfod-find - request debuginfo-related data
SYNOPSIS
debuginfod-find [OPTION]... debuginfo BUILDID
debuginfod-find [OPTION]... debuginfo PATH
debuginfod-find [OPTION]... executable BUILDID
debuginfod-find [OPTION]... executable PATH
debuginfod-find [OPTION]... source BUILDID /FILENAME
debuginfod-find [OPTION]... source PATH /FILENAME
DESCRIPTION
debuginfod-find queries one or more debuginfod servers for debuginfo-
related data. In case of a match, it saves the the requested file into
a local cache, prints the file name to standard output, and exits with
a success status of 0. In case of any error, it exits with a failure
status and an error message to standard error.
The debuginfod system uses buildids to identify debuginfo-related data.
These are stored as binary notes in ELF/DWARF files, and are repre-
sented as lowercase hexadecimal. For example, for a program /bin/ls,
look at the ELF note GNU_BUILD_ID:
% readelf -n /bin/ls | grep -A4 build.id
Note section [ 4] '.note.gnu.buildid' of 36 bytes at offset 0x340:
Owner Data size Type
GNU 20 GNU_BUILD_ID
Build ID: 8713b9c3fb8a720137a4a08b325905c7aaf8429d
Then the hexadecimal BUILDID is simply:
8713b9c3fb8a720137a4a08b325905c7aaf8429d
In place of the hexadecimal BUILDID, debuginfod-find also accepts a
path name to to an ELF binary, from which it extracts the buildid. In
this case, ensure the file name has some character other than [0-9a-f].
Files ambiguously named files like "deadbeef" can be passed with a
./deadbeef extra path component.
debuginfo BUILDID
If the given buildid is known to a server, this request will result in
a binary object that contains the customary .*debug_* sections. This
may be a split debuginfo file as created by strip, or it may be an
original unstripped executable.
executable BUILDID
If the given buildid is known to the server, this request will result
in a binary object that contains the normal executable segments. This
may be a executable stripped by strip, or it may be an original un-
stripped executable. ET_DYN shared libraries are considered to be a
type of executable.
source BUILDID /SOURCE/FILE
If the given buildid is known to the server, this request will result
in a binary object that contains the source file mentioned. The path
should be absolute. Relative path names commonly appear in the DWARF
file's source directory, but these paths are relative to individual
compilation unit AT_comp_dir paths, and yet an executable is made up of
multiple CUs. Therefore, to disambiguate, debuginfod expects source
queries to prefix relative path names with the CU compilation-directo-
ry, followed by a mandatory "/".
Note: for software packaged by distributions, the CU compilation-direc-
tory may not be obvious. It can be found by inspecting AT_comp_dir
values in downloaded debuginfo. For example, the comp_dir of the Fedo-
ra 37 version of /bin/ls can be found as follows:
% debuginfod-find debuginfo /bin/ls
~/.cache/debuginfod_client/03529d48345409576cd5c82a56ad08555088d353/
% eu-readelf -w ~/.cache/debuginfod_client/03529d48345409576cd5c82a56ad08555088d353/debuginfo | grep comp_dir
comp_dir (line_strp) "/usr/src/debug/coreutils-9.1-6.fc37.x86_64/separate"
Note: the caller may or may not elide ../ or /./ or extraneous ///
sorts of path components in the directory names. debuginfod accepts
both forms. Specifically, debuginfod canonicalizes path names accord-
ing to RFC3986 section 5.2.4 (Remove Dot Segments), plus reducing any
// to / in the path.
For example:
#include <stdio.h> source BUILDID /usr/include/stdio.h
/path/to/foo.c source BUILDID /path/to/foo.c
../bar/foo.c AT_comp_dir=/zoo/ source BUILDID /zoo//../bar/foo.c
OPTIONS
-v Increase verbosity, including printing frequent download-
progress messages and printing the http response headers from
the server.
SECURITY
debuginfod-find does not include any particular security features. It
trusts that the binaries returned by the debuginfod(s) are accurate.
Therefore, the list of servers should include only trustworthy ones.
If accessed across HTTP rather than HTTPS, the network should be trust-
worthy. Authentication information through the internal libcurl li-
brary is not currently enabled, except for the basic plaintext
http[s]://userid:password@hostname/ style. (The debuginfod server does
not perform authentication, but a front-end proxy server could.)
ENVIRONMENT VARIABLES
$TMPDIR
This environment variable points to a file system to be used for
temporary files. The default is /tmp.
$DEBUGINFOD_URLS
This environment variable contains a list of URL prefixes for
trusted debuginfod instances. Alternate URL prefixes are sepa-
rated by space. This environment variable may be set by
/etc/profile.d scripts reading /etc/debuginfod/*.urls files.
$DEBUGINFOD_CACHE_PATH
This environment variable governs the location of the cache
where downloaded files and cache-control files are kept. The
default directory is chosen based on other environment vari-
ables, see below.
$DEBUGINFOD_PROGRESS
This environment variable governs the default progress function.
If set, and if a progressfn is not explicitly set, then the li-
brary will configure a default progressfn. This function will
append a simple progress message periodically to stderr. The
default is no progress function output.
$DEBUGINFOD_VERBOSE
This environment variable governs the default file descriptor
for verbose output. If set, and if a verbose fd is not explic-
itly set, then the verbose output will be produced on
STDERR_FILENO.
$DEBUGINFOD_RETRY_LIMIT
This environment variable governs the default limit of retry at-
tempts. If a query failed with errno other than ENOENT, will
initiate several attempts within the limit.
$DEBUGINFOD_TIMEOUT
This environment variable governs the download commencing time-
out for each debuginfod HTTP connection. A server that fails to
provide at least 100K of data within this many seconds is
skipped. The default is 90 seconds. (Zero or negative means "no
timeout".)
$DEBUGINFOD_MAXTIME
This environment variable dictates how long the client will wait
to complete the download a file found on a server in seconds. It
is best used to ensure that a file is downloaded quickly or be
rejected. The default is 0 (infinite time).
$DEBUGINFOD_MAXSIZE
This environment variable dictates the maximum size of a file to
download in bytes. This is best used if the user would like to
ensure only small files are downloaded. A value of 0 causes no
consideration for size, and the client may attempt to download a
file of any size. The default is 0 (infinite size).
$DEBUGINFOD_HEADERS_FILE
This environment variable points to a file that supplies headers
to outbound HTTP requests, one per line. The header lines
shouldn't end with CRLF, unless that's the system newline con-
vention. Whitespace-only lines are skipped.
CACHE
Before each query, the debuginfod client library checks for a need to
clean the cache. If it's time to clean, the library traverses the
cache directory and removes downloaded debuginfo-related artifacts and
newly empty directories, if they have not been accessed recently.
Control files are located directly under the cache directory. They
contain simple decimal numbers to set cache-related configuration pa-
rameters. If the files do not exist, the client library creates the
files with the default parameter values as content.
After each query, the debuginfod client library deposits newly received
files into a directory & file that is named based on the build-id. A
failed query is also cached by a special file. The naming convention
used for these artifacts is deliberately undocumented.
$XDG_CACHE_HOME/debuginfod_client/
Default cache directory, if $XDG_CACHE_HOME is set.
$HOME/.cache/debuginfod_client/
Default cache directory, if $XDG_CACHE_HOME is not set.
$HOME/.debuginfod_client_cache/
Deprecated cache directory, used only if preexisting.
cache_clean_interval_s
This control file gives the interval between cache cleaning
rounds, in seconds. The default is 86400, one day. 0 means
"immediately".
max_unused_age_s
This control file sets how long unaccessed debuginfo-related
files are retained, in seconds. The default is 604800, one
week. 0 means "immediately".
cache_miss_s
This control file sets how long to remember a query failure, in
seconds. New queries for the same artifacts within this time
window are short-circuited (returning an immediate failure in-
stead of sending a new query to servers). This accelerates
queries that probably would still fail. The default is 600, 10
minutes. 0 means "forget immediately".
SEE ALSO
debuginfod(8) debuginfod_find_debuginfod(3)
DEBUGINFOD-FIND(1)
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