commit 76ad56c430f0b85c47115688c511d9bd4fa671d4

Author: Frank Ch. Eigler <fche@redhat.com>

Date:   Wed Dec 4 15:51:12 2019 -0500

    debuginfod: usability tweaks, incl. $DEBUGINFOD_PROGRESS client support

    This facility allows a default progress-printing function to be

    installed if the given environment variable is set.  Some larger usage

    experience (systemtap fetching kernels) indicates the default timeout

    is too short, so forked it into a connection timeout (default short)

    and a transfer timeout (default unlimited).

    Signed-off-by: Frank Ch. Eigler <fche@redhat.com>

diff --git a/debuginfod/debuginfod-client.c b/debuginfod/debuginfod-client.c

index ab7b4e1..9a4a0e0 100644

--- a/debuginfod/debuginfod-client.c

+++ b/debuginfod/debuginfod-client.c

@@ -40,6 +40,7 @@

 #include "config.h"

 #include "debuginfod.h"

+#include "system.h"

 #include <assert.h>

 #include <dirent.h>

 #include <stdio.h>

@@ -98,16 +99,16 @@ static const time_t cache_default_max_unused_age_s = 604800; /* 1 week */

 static const char *cache_default_name = ".debuginfod_client_cache";

 static const char *cache_path_envvar = DEBUGINFOD_CACHE_PATH_ENV_VAR;

-/* URLs of debuginfods, separated by url_delim.

-   This env var must be set for debuginfod-client to run.  */

+/* URLs of debuginfods, separated by url_delim. */

 static const char *server_urls_envvar = DEBUGINFOD_URLS_ENV_VAR;

 static const char *url_delim =  " ";

 static const char url_delim_char = ' ';

-/* Timeout for debuginfods, in seconds.

-   This env var must be set for debuginfod-client to run.  */

+/* Timeout for debuginfods, in seconds. */

 static const char *server_timeout_envvar = DEBUGINFOD_TIMEOUT_ENV_VAR;

-static int server_timeout = 5;

+static const long default_connect_timeout = 5;

+static const long default_transfer_timeout = -1; /* unlimited */

+

 /* Data associated with a particular CURL easy handle. Passed to

    the write callback.  */

@@ -400,8 +401,18 @@ debuginfod_query_server (debuginfod_client *c,

       return fd;

     }

-  if (getenv(server_timeout_envvar))

-    server_timeout = atoi (getenv(server_timeout_envvar));

+  long connect_timeout = default_connect_timeout;

+  long transfer_timeout = default_transfer_timeout;

+  const char* timeout_envvar = getenv(server_timeout_envvar);

+  if (timeout_envvar != NULL)

+    {

+      long ct, tt;

+      rc = sscanf(timeout_envvar, "%ld,%ld", &ct, &tt;;

+      if (rc >= 1)

+        connect_timeout = ct;

+      if (rc >= 2)

+        transfer_timeout = tt;

+    }

   /* make a copy of the envvar so it can be safely modified.  */

   server_urls = strdup(urls_envvar);

@@ -493,7 +504,10 @@ debuginfod_query_server (debuginfod_client *c,

                        CURLOPT_WRITEFUNCTION,

                        debuginfod_write_callback);

       curl_easy_setopt(data[i].handle, CURLOPT_WRITEDATA, (void*)&data[i]);

-      curl_easy_setopt(data[i].handle, CURLOPT_TIMEOUT, (long) server_timeout);

+      if (connect_timeout >= 0)

+        curl_easy_setopt(data[i].handle, CURLOPT_CONNECTTIMEOUT, connect_timeout);

+      if (transfer_timeout >= 0)

+        curl_easy_setopt(data[i].handle, CURLOPT_TIMEOUT, transfer_timeout);

       curl_easy_setopt(data[i].handle, CURLOPT_FILETIME, (long) 1);

       curl_easy_setopt(data[i].handle, CURLOPT_FOLLOWLOCATION, (long) 1);

       curl_easy_setopt(data[i].handle, CURLOPT_FAILONERROR, (long) 1);

@@ -511,11 +525,32 @@ debuginfod_query_server (debuginfod_client *c,

   long loops = 0;

   do

     {

+      /* Wait 1 second, the minimum DEBUGINFOD_TIMEOUT.  */

+      curl_multi_wait(curlm, NULL, 0, 1000, NULL);

+

+      /* If the target file has been found, abort the other queries.  */

+      if (target_handle != NULL)

+        for (int i = 0; i < num_urls; i++)

+          if (data[i].handle != target_handle)

+            curl_multi_remove_handle(curlm, data[i].handle);

+

+      CURLMcode curlm_res = curl_multi_perform(curlm, &still_running);

+      if (curlm_res != CURLM_OK)

+        {

+          switch (curlm_res)

+            {

+            case CURLM_CALL_MULTI_PERFORM: continue;

+            case CURLM_OUT_OF_MEMORY: rc = -ENOMEM; break;

+            default: rc = -ENETUNREACH; break;

+            }

+          goto out1;

+        }

+

       if (c->progressfn) /* inform/check progress callback */

         {

           loops ++;

           long pa = loops; /* default params for progress callback */

-          long pb = 0;

+          long pb = 0; /* transfer_timeout tempting, but loops != elapsed-time */

           if (target_handle) /* we've committed to a server; report its download progress */

             {

               CURLcode curl_res;

@@ -535,6 +570,8 @@ debuginfod_query_server (debuginfod_client *c,

                 pa = (dl > LONG_MAX ? LONG_MAX : (long)dl);

 #endif

+              /* NB: If going through deflate-compressing proxies, this

+                 number is likely to be unavailable, so -1 may show. */

 #ifdef CURLINFO_CURLINFO_CONTENT_LENGTH_DOWNLOAD_T

               curl_off_t cl;

               curl_res = curl_easy_getinfo(target_handle,

@@ -555,27 +592,6 @@ debuginfod_query_server (debuginfod_client *c,

           if ((*c->progressfn) (c, pa, pb))

             break;

         }

-

-      /* Wait 1 second, the minimum DEBUGINFOD_TIMEOUT.  */

-      curl_multi_wait(curlm, NULL, 0, 1000, NULL);

-

-      /* If the target file has been found, abort the other queries.  */

-      if (target_handle != NULL)

-        for (int i = 0; i < num_urls; i++)

-          if (data[i].handle != target_handle)

-            curl_multi_remove_handle(curlm, data[i].handle);

-

-      CURLMcode curlm_res = curl_multi_perform(curlm, &still_running);

-      if (curlm_res != CURLM_OK)

-        {

-          switch (curlm_res)

-            {

-            case CURLM_CALL_MULTI_PERFORM: continue;

-            case CURLM_OUT_OF_MEMORY: rc = -ENOMEM; break;

-            default: rc = -ENETUNREACH; break;

-            }

-          goto out1;

-        }

     } while (still_running);

   /* Check whether a query was successful. If so, assign its handle

@@ -674,9 +690,9 @@ debuginfod_query_server (debuginfod_client *c,

   curl_multi_cleanup(curlm);

   unlink (target_cache_tmppath);

+  close (fd); /* before the rmdir, otherwise it'll fail */

   (void) rmdir (target_cache_dir); /* nop if not empty */

   free(data);

-  close (fd);

  out0:

   free (server_urls);

@@ -685,6 +701,22 @@ debuginfod_query_server (debuginfod_client *c,

   return rc;

 }

+

+/* Activate a basic form of progress tracing */

+static int

+default_progressfn (debuginfod_client *c, long a, long b)

+{

+  (void) c;

+

+  dprintf(STDERR_FILENO,

+          "Downloading from debuginfod %ld/%ld%s", a, b,

+          ((a == b) ? "\n" : "\r"));

+  /* XXX: include URL - stateful */

+

+  return 0;

+}

+

+

 /* See debuginfod.h  */

 debuginfod_client  *

 debuginfod_begin (void)

@@ -693,7 +725,12 @@ debuginfod_begin (void)

   size_t size = sizeof (struct debuginfod_client);

   client = (debuginfod_client *) malloc (size);

   if (client != NULL)

-    client->progressfn = NULL;

+    {

+      if (getenv(DEBUGINFOD_PROGRESS_ENV_VAR))

+	client->progressfn = default_progressfn;

+      else

+	client->progressfn = NULL;

+    }

   return client;

 }

diff --git a/debuginfod/debuginfod.h b/debuginfod/debuginfod.h

index 6b1b1cc..33fae86 100644

--- a/debuginfod/debuginfod.h

+++ b/debuginfod/debuginfod.h

@@ -33,6 +33,7 @@

 #define DEBUGINFOD_URLS_ENV_VAR "DEBUGINFOD_URLS"

 #define DEBUGINFOD_CACHE_PATH_ENV_VAR "DEBUGINFOD_CACHE_PATH"

 #define DEBUGINFOD_TIMEOUT_ENV_VAR "DEBUGINFOD_TIMEOUT"

+#define DEBUGINFOD_PROGRESS_ENV_VAR "DEBUGINFOD_PROGRESS"

 /* Handle for debuginfod-client connection.  */

 typedef struct debuginfod_client debuginfod_client;

diff --git a/doc/debuginfod-find.1 b/doc/debuginfod-find.1

index a759ecb..023acbb 100644

--- a/doc/debuginfod-find.1

+++ b/doc/debuginfod-find.1

@@ -119,9 +119,13 @@ debuginfod instances.  Alternate URL prefixes are separated by space.

 .TP 21

 .B DEBUGINFOD_TIMEOUT

-This environment variable governs the timeout for each debuginfod HTTP

-connection.  A server that fails to respond within this many seconds

-is skipped.  The default is 5.

+This environment variable governs the timeouts for each debuginfod

+HTTP connection.  One or two comma-separated numbers may be given.

+The first is the number of seconds for the connection establishment

+(CURLOPT_CONNECTTIMEOUT), and the default is 5.  The second is the

+number of seconds for the transfer completion (CURLOPT_TIMEOUT), and

+the default is no timeout.  (Zero or negative also means "no

+timeout".)

 .TP 21

 .B DEBUGINFOD_CACHE_PATH

diff --git a/doc/debuginfod_find_debuginfo.3 b/doc/debuginfod_find_debuginfo.3

index be8eed0..ea8c616 100644

--- a/doc/debuginfod_find_debuginfo.3

+++ b/doc/debuginfod_find_debuginfo.3

@@ -163,9 +163,21 @@ debuginfod instances.  Alternate URL prefixes are separated by space.

 .TP 21

 .B DEBUGINFOD_TIMEOUT

-This environment variable governs the timeout for each debuginfod HTTP

-connection.  A server that fails to respond within this many seconds

-is skipped.  The default is 5.

+This environment variable governs the timeouts for each debuginfod

+HTTP connection.  One or two comma-separated numbers may be given.

+The first is the number of seconds for the connection establishment

+(CURLOPT_CONNECTTIMEOUT), and the default is 5.  The second is the

+number of seconds for the transfer completion (CURLOPT_TIMEOUT), and

+the default is no timeout.  (Zero or negative also means "no

+timeout".)

+

+.TP 21

+.B DEBUGINFOD_PROGRESS

+This environment variable governs the default progress function.  If

+set, and if a progressfn is not explicitly set, then the library will

+configure a default progressfn.  This function will append a simple

+progress message periodically to the given file.  Consider using

+"/dev/stderr" on platforms that support it.  The default is nothing.

 .TP 21

 .B DEBUGINFOD_CACHE_PATH

diff --git a/tests/run-debuginfod-find.sh b/tests/run-debuginfod-find.sh

index 6533996..4cf6138 100755

--- a/tests/run-debuginfod-find.sh

+++ b/tests/run-debuginfod-find.sh

@@ -89,7 +89,7 @@ wait_ready $PORT1 'ready' 1

 export DEBUGINFOD_URLS=http://127.0.0.1:$PORT1/   # or without trailing /

 # Be patient when run on a busy machine things might take a bit.

-export DEBUGINFOD_TIMEOUT=10

+export DEBUGINFOD_TIMEOUT=1,10

 # We use -t0 and -g0 here to turn off time-based scanning & grooming.

 # For testing purposes, we just sic SIGUSR1 / SIGUSR2 at the process.

@@ -153,8 +153,11 @@ cmp $filename F/prog2

 cat vlog

 grep -q Progress vlog

 tempfiles vlog

-filename=`testrun ${abs_top_builddir}/debuginfod/debuginfod-find executable $BUILDID2`

+filename=`testrun env DEBUGINFOD_PROGRESS=1 ${abs_top_builddir}/debuginfod/debuginfod-find executable $BUILDID2 2>vlog2`

 cmp $filename F/prog2

+cat vlog2

+grep -q Downloading vlog2

+tempfiles vlog2

 filename=`testrun ${abs_top_builddir}/debuginfod/debuginfod-find source $BUILDID2 ${PWD}/prog2.c`

 cmp $filename ${PWD}/prog2.c

commit 288c76775f2d27976eb269e568b53c742d973dbc

Author: Frank Ch. Eigler <fche@redhat.com>

Date:   Mon Jan 6 04:29:21 2020 -0500

    debuginfod: pass a distro-summary User-Agent request header

    It may be useful for a debuginfod server operator to know what kinds

    of clients make webapi requests.  This is mainly as a

    telemetry/diagnostic (though the data cannot be really trusted).  It

    may also be useful to automate downloading of distro packages to a

    debuginfod server in the case of an unknown hex buildid.  doc/testing

    not affected as these are diagnostics.

    Signed-off-by: Frank Ch. Eigler <fche@redhat.com>

    Signed-off-by: Mark Wielaard <mjw@redhat.com>

diff --git a/debuginfod/debuginfod-client.c b/debuginfod/debuginfod-client.c

index 9a4a0e0..66ccb21 100644

--- a/debuginfod/debuginfod-client.c

+++ b/debuginfod/debuginfod-client.c

@@ -1,5 +1,5 @@

 /* Retrieve ELF / DWARF / source files from the debuginfod.

-   Copyright (C) 2019 Red Hat, Inc.

+   Copyright (C) 2019-2020 Red Hat, Inc.

    This file is part of elfutils.

    This file is free software; you can redistribute it and/or modify

@@ -58,6 +58,7 @@

 #include <sys/syscall.h>

 #include <sys/types.h>

 #include <sys/stat.h>

+#include <sys/utsname.h>

 #include <curl/curl.h>

 /* If fts.h is included before config.h, its indirect inclusions may not

@@ -279,6 +280,87 @@ debuginfod_clean_cache(debuginfod_client *c,

 #define MAX_BUILD_ID_BYTES 64

+static void

+add_extra_headers(CURL *handle)

+{

+  /* Compute a User-Agent: string to send.  The more accurately this

+     describes this host, the likelier that the debuginfod servers

+     might be able to locate debuginfo for us. */

+

+  char* utspart = NULL;

+  struct utsname uts;

+  int rc = 0;

+  rc = uname (&uts;;

+  if (rc == 0)

+    rc = asprintf(& utspart, "%s/%s", uts.sysname, uts.machine);

+  if (rc < 0)

+    utspart = NULL;

+

+  FILE *f = fopen ("/etc/os-release", "r");

+  if (f == NULL)

+    f = fopen ("/usr/lib/os-release", "r");

+  char *id = NULL;

+  char *version = NULL;

+  if (f != NULL)

+    {

+      while (id == NULL || version == NULL)

+        {

+          char buf[128];

+          char *s = &buf[0];

+          if (fgets (s, sizeof(buf), f) == NULL)

+            break;

+

+          int len = strlen (s);

+          if (len < 3)

+            continue;

+          if (s[len - 1] == '\n')

+            {

+              s[len - 1] = '\0';

+              len--;

+            }

+

+          char *v = strchr (s, '=');

+          if (v == NULL || strlen (v) < 2)

+            continue;

+

+          /* Split var and value. */

+          *v = '\0';

+          v++;

+

+          /* Remove optional quotes around value string. */

+          if (*v == '"' || *v == '\'')

+            {

+              v++;

+              s[len - 1] = '\0';

+            }

+          if (strcmp (s, "ID") == 0)

+            id = strdup (v);

+          if (strcmp (s, "VERSION_ID") == 0)

+            version = strdup (v);

+        }

+      fclose (f);

+    }

+

+  char *ua = NULL;

+  rc = asprintf(& ua, "%s/%s,%s,%s/%s",

+                PACKAGE_NAME, PACKAGE_VERSION,

+                utspart ?: "",

+                id ?: "",

+                version ?: "");

+  if (rc < 0)

+    ua = NULL;

+

+  if (ua)

+    curl_easy_setopt(handle, CURLOPT_USERAGENT, (void*) ua); /* implicit strdup */

+

+  free (ua);

+  free (id);

+  free (version);

+  free (utspart);

+}

+

+

+

 /* Query each of the server URLs found in $DEBUGINFOD_URLS for the file

    with the specified build-id, type (debuginfo, executable or source)

    and filename. filename may be NULL. If found, return a file

@@ -514,7 +596,7 @@ debuginfod_query_server (debuginfod_client *c,

       curl_easy_setopt(data[i].handle, CURLOPT_NOSIGNAL, (long) 1);

       curl_easy_setopt(data[i].handle, CURLOPT_AUTOREFERER, (long) 1);

       curl_easy_setopt(data[i].handle, CURLOPT_ACCEPT_ENCODING, "");

-      curl_easy_setopt(data[i].handle, CURLOPT_USERAGENT, (void*) PACKAGE_STRING);

+      add_extra_headers(data[i].handle);

       curl_multi_add_handle(curlm, data[i].handle);

       server_url = strtok_r(NULL, url_delim, &strtok_saveptr);

commit b8d85ed024a745cff05e56c6337d95d654d5294a

Author: Mark Wielaard <mark@klomp.org>

Date:   Thu Jan 2 17:02:42 2020 +0100

    debuginfod: Use DEBUGINFOD_TIMEOUT as seconds to get at least 100K.

    Use just one timeout using CURLOPT_LOW_SPEED_TIME (default 90 seconds)

    and CURLOPT_LOW_SPEED_LIMIT (100K).

    Signed-off-by: Mark Wielaard <mark@klomp.org>

diff --git a/debuginfod/debuginfod-client.c b/debuginfod/debuginfod-client.c

index 66ccb21..e5a2e82 100644

--- a/debuginfod/debuginfod-client.c

+++ b/debuginfod/debuginfod-client.c

@@ -105,10 +105,9 @@ static const char *server_urls_envvar = DEBUGINFOD_URLS_ENV_VAR;

 static const char *url_delim =  " ";

 static const char url_delim_char = ' ';

-/* Timeout for debuginfods, in seconds. */

+/* Timeout for debuginfods, in seconds (to get at least 100K). */

 static const char *server_timeout_envvar = DEBUGINFOD_TIMEOUT_ENV_VAR;

-static const long default_connect_timeout = 5;

-static const long default_transfer_timeout = -1; /* unlimited */

+static const long default_timeout = 90;

 /* Data associated with a particular CURL easy handle. Passed to

@@ -483,18 +482,10 @@ debuginfod_query_server (debuginfod_client *c,

       return fd;

     }

-  long connect_timeout = default_connect_timeout;

-  long transfer_timeout = default_transfer_timeout;

+  long timeout = default_timeout;

   const char* timeout_envvar = getenv(server_timeout_envvar);

   if (timeout_envvar != NULL)

-    {

-      long ct, tt;

-      rc = sscanf(timeout_envvar, "%ld,%ld", &ct, &tt;;

-      if (rc >= 1)

-        connect_timeout = ct;

-      if (rc >= 2)

-        transfer_timeout = tt;

-    }

+    timeout = atoi (timeout_envvar);

   /* make a copy of the envvar so it can be safely modified.  */

   server_urls = strdup(urls_envvar);

@@ -586,10 +577,15 @@ debuginfod_query_server (debuginfod_client *c,

                        CURLOPT_WRITEFUNCTION,

                        debuginfod_write_callback);

       curl_easy_setopt(data[i].handle, CURLOPT_WRITEDATA, (void*)&data[i]);

-      if (connect_timeout >= 0)

-        curl_easy_setopt(data[i].handle, CURLOPT_CONNECTTIMEOUT, connect_timeout);

-      if (transfer_timeout >= 0)

-        curl_easy_setopt(data[i].handle, CURLOPT_TIMEOUT, transfer_timeout);

+      if (timeout > 0)

+	{

+	  /* Make sure there is at least some progress,

+	     try to get at least 100K per timeout seconds.  */

+	  curl_easy_setopt (data[i].handle, CURLOPT_LOW_SPEED_TIME,

+			    timeout);

+	  curl_easy_setopt (data[i].handle, CURLOPT_LOW_SPEED_LIMIT,

+			    100 * 1024L);

+	}

       curl_easy_setopt(data[i].handle, CURLOPT_FILETIME, (long) 1);

       curl_easy_setopt(data[i].handle, CURLOPT_FOLLOWLOCATION, (long) 1);

       curl_easy_setopt(data[i].handle, CURLOPT_FAILONERROR, (long) 1);

diff --git a/doc/debuginfod-find.1 b/doc/debuginfod-find.1

index 023acbb..e71ca29 100644

--- a/doc/debuginfod-find.1

+++ b/doc/debuginfod-find.1

@@ -119,13 +119,10 @@ debuginfod instances.  Alternate URL prefixes are separated by space.

 .TP 21

 .B DEBUGINFOD_TIMEOUT

-This environment variable governs the timeouts for each debuginfod

-HTTP connection.  One or two comma-separated numbers may be given.

-The first is the number of seconds for the connection establishment

-(CURLOPT_CONNECTTIMEOUT), and the default is 5.  The second is the

-number of seconds for the transfer completion (CURLOPT_TIMEOUT), and

-the default is no timeout.  (Zero or negative also means "no

-timeout".)

+This environment variable governs the timeout 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".)

 .TP 21

 .B DEBUGINFOD_CACHE_PATH

diff --git a/doc/debuginfod.8 b/doc/debuginfod.8

index 342f524..6184bcc 100644

--- a/doc/debuginfod.8

+++ b/doc/debuginfod.8

@@ -366,8 +366,10 @@ or indirectly - the results would be hilarious.

 .TP 21

 .B DEBUGINFOD_TIMEOUT

 This environment variable governs the timeout for each debuginfod HTTP

-connection.  A server that fails to respond within this many seconds

-is skipped.  The default is 5.

+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".)

+

 .TP 21

 .B DEBUGINFOD_CACHE_PATH

diff --git a/doc/debuginfod_find_debuginfo.3 b/doc/debuginfod_find_debuginfo.3

index ea8c616..f6ea7a4 100644

--- a/doc/debuginfod_find_debuginfo.3

+++ b/doc/debuginfod_find_debuginfo.3

@@ -163,13 +163,10 @@ debuginfod instances.  Alternate URL prefixes are separated by space.

 .TP 21

 .B DEBUGINFOD_TIMEOUT

-This environment variable governs the timeouts for each debuginfod

-HTTP connection.  One or two comma-separated numbers may be given.

-The first is the number of seconds for the connection establishment

-(CURLOPT_CONNECTTIMEOUT), and the default is 5.  The second is the

-number of seconds for the transfer completion (CURLOPT_TIMEOUT), and

-the default is no timeout.  (Zero or negative also means "no

-timeout".)

+This environment variable governs the timeout 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".)

 .TP 21

 .B DEBUGINFOD_PROGRESS

diff --git a/tests/run-debuginfod-find.sh b/tests/run-debuginfod-find.sh

index 90dafe0..4ab47a3 100755

--- a/tests/run-debuginfod-find.sh

+++ b/tests/run-debuginfod-find.sh

@@ -94,7 +94,7 @@ wait_ready $PORT1 'ready' 1

 export DEBUGINFOD_URLS=http://127.0.0.1:$PORT1/   # or without trailing /

 # Be patient when run on a busy machine things might take a bit.

-export DEBUGINFOD_TIMEOUT=1,10

+export DEBUGINFOD_TIMEOUT=10

 # We use -t0 and -g0 here to turn off time-based scanning & grooming.

 # For testing purposes, we just sic SIGUSR1 / SIGUSR2 at the process.

commit 6f2098114a1acbd5e320a1c5fabfa07df02b14fd

Author: Mark Wielaard <mark@klomp.org>

Date:   Fri Jan 10 15:46:29 2020 +0100

    doc: Fix DEBUGINFOD_PROGRESS description to just mention output on stderr.

    An earlier variant of the default progress function could write to any

    file. Which is still in the documentation. But the actual implementation

    just uses stderr. Fix the documentation to match.

    Signed-off-by: Mark Wielaard <mark@klomp.org>

diff --git a/doc/debuginfod_find_debuginfo.3 b/doc/debuginfod_find_debuginfo.3

index f6ea7a4..7e5060f 100644

--- a/doc/debuginfod_find_debuginfo.3

+++ b/doc/debuginfod_find_debuginfo.3

@@ -173,8 +173,8 @@ or negative means "no timeout".)

 This environment variable governs the default progress function.  If

 set, and if a progressfn is not explicitly set, then the library will

 configure a default progressfn.  This function will append a simple

-progress message periodically to the given file.  Consider using

-"/dev/stderr" on platforms that support it.  The default is nothing.

+progress message periodically to stderr.  The default is no progress

+function output.

 .TP 21

 .B DEBUGINFOD_CACHE_PATH