glibc/stdlib/fmtmsg.c

/* Copyright (C) 1997-2025 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, see
   <https://www.gnu.org/licenses/>.  */

#include <fmtmsg.h>
#include <libc-lock.h>
#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <sys/syslog.h>
#include <wchar.h>


/* We have global data, protect the modification.  */
__libc_lock_define_initialized (static, lock)


enum
{
  label_mask = 0x01,
  severity_mask = 0x02,
  text_mask = 0x04,
  action_mask = 0x08,
  tag_mask = 0x10,
  all_mask = label_mask | severity_mask | text_mask | action_mask | tag_mask
};

static const struct
{
  uint32_t len;
  /* Adjust the size if new elements are added.  */
  const char name[12];
} keywords[] =
  {
    { 5, "label" },
    { 8, "severity" },
    { 4, "text" },
    { 6, "action"},
    { 3, "tag" }
  };
#define NKEYWORDS (sizeof (keywords) / sizeof (keywords[0]))


struct severity_info
{
  int severity;
  const char *string;
  struct severity_info *next;
};


/* List of known severities.  */
static const struct severity_info nosev =
{
  MM_NOSEV, "", NULL
};
static const struct severity_info haltsev =
{
  MM_HALT, "HALT", (struct severity_info *) &nosev
};
static const struct severity_info errorsev =
{
  MM_ERROR, "ERROR", (struct severity_info *) &haltsev
};
static const struct severity_info warningsev =
{
  MM_WARNING, "WARNING", (struct severity_info *) &errorsev
};
static const struct severity_info infosev =
{
  MM_INFO, "INFO", (struct severity_info *) &warningsev
};

/* Start of the list.  */
static struct severity_info *severity_list = (struct severity_info *) &infosev;

/* Mask of values we will print.  */
static int print;

/* Prototypes for local functions.  */
static void init (void);
static int internal_addseverity (int severity, const char *string);


int
fmtmsg (long int classification, const char *label, int severity,
	const char *text, const char *action, const char *tag)
{
  __libc_once_define (static, once);
  struct severity_info *severity_rec;

  /* Make sure everything is initialized.  */
  __libc_once (once, init);

  /* Start the real work.  First check whether the input is ok.  */
  if (label != MM_NULLLBL)
    {
      /* Must be two fields, separated by a colon.  */
      const char *cp = strchr (label, ':');
      if (cp == NULL)
	return MM_NOTOK;

      /* The first field must not contain more than 10 bytes.  */
      if (cp - label > 10
	  /* The second field must not have more than 14 bytes.  */
	  || strlen (cp + 1) > 14)
	return MM_NOTOK;
    }

  /* We do not want this call to be cut short by a thread
     cancellation.  Therefore disable cancellation for now.  */
  int state = PTHREAD_CANCEL_ENABLE;
  __pthread_setcancelstate (PTHREAD_CANCEL_DISABLE, &state);

  __libc_lock_lock (lock);

  for (severity_rec = severity_list; severity_rec != NULL;
       severity_rec = severity_rec->next)
    if (severity == severity_rec->severity)
      /* Bingo.  */
      break;

  /* If we don't know anything about the severity level return an error.  */
  int result = MM_NOTOK;
  if (severity_rec != NULL)
    {
      result = MM_OK;

      /* Now we can print.  */
      if (classification & MM_PRINT)
	{
	  int do_label = (print & label_mask) && label != MM_NULLLBL;
	  int do_severity = (print & severity_mask) && severity != MM_NULLSEV;
	  int do_text = (print & text_mask) && text != MM_NULLTXT;
	  int do_action = (print & action_mask) && action != MM_NULLACT;
	  int do_tag = (print & tag_mask) && tag != MM_NULLTAG;
	  int need_colon = (do_label
			    && (do_severity | do_text | do_action | do_tag));

	  if (__fxprintf (stderr, "%s%s%s%s%s%s%s%s%s%s\n",
			  do_label ? label : "",
			  need_colon ? ": " : "",
			  do_severity ? severity_rec->string : "",
			  do_severity && (do_text | do_action | do_tag)
			  ? ": " : "",
			  do_text ? text : "",
			  do_text && (do_action | do_tag) ? "\n" : "",
			  do_action ? "TO FIX: " : "",
			  do_action ? action : "",
			  do_action && do_tag ? "  " : "",
			  do_tag ? tag : "") < 0)
	    /* Oh, oh.  An error occurred during the output.  */
	    result = MM_NOMSG;
	}

      if (classification & MM_CONSOLE)
	{
	  int do_label = label != MM_NULLLBL;
	  int do_severity = severity != MM_NULLSEV;
	  int do_text = text != MM_NULLTXT;
	  int do_action = action != MM_NULLACT;
	  int do_tag = tag != MM_NULLTAG;
	  int need_colon = (do_label
			    && (do_severity | do_text | do_action | do_tag));

	  syslog (LOG_ERR, "%s%s%s%s%s%s%s%s%s%s\n",
		  do_label ? label : "",
		  need_colon ? ": " : "",
		  do_severity ? severity_rec->string : "",
		  do_severity && (do_text | do_action | do_tag) ? ": " : "",
		  do_text ? text : "",
		  do_text && (do_action | do_tag) ? "\n" : "",
		  do_action ? "TO FIX: " : "",
		  do_action ? action : "",
		  do_action && do_tag ? "  " : "",
		  do_tag ? tag : "");
	}
    }

  __libc_lock_unlock (lock);

  __pthread_setcancelstate (state, NULL);

  return result;
}


/* Initialize from environment variable content.  */
static void
init (void)
{
  const char *msgverb_var = getenv ("MSGVERB");
  const char *sevlevel_var = getenv ("SEV_LEVEL");

  if (msgverb_var != NULL && msgverb_var[0] != '\0')
    {
      /* Using this extra variable allows us to work without locking.  */
      do
	{
	  size_t cnt;

	  for (cnt = 0; cnt < NKEYWORDS; ++cnt)
	    if (memcmp (msgverb_var,
			keywords[cnt].name, keywords[cnt].len) == 0
		&& (msgverb_var[keywords[cnt].len] == ':'
		    || msgverb_var[keywords[cnt].len] == '\0'))
	      break;

	  if (cnt < NKEYWORDS)
	    {
	      print |= 1 << cnt;

	      msgverb_var += keywords[cnt].len;
	      if (msgverb_var[0] == ':')
		++msgverb_var;
	    }
	  else
	    {
	      /* We found an illegal keyword in the environment
		 variable.  The specifications say that we print all
		 fields.  */
	      print = all_mask;
	      break;
	    }
	}
      while (msgverb_var[0] != '\0');
    }
  else
    print = all_mask;


  if (sevlevel_var != NULL)
    {
      __libc_lock_lock (lock);

      while (sevlevel_var[0] != '\0')
	{
	  const char *end = __strchrnul (sevlevel_var, ':');
	  int level;

	  /* First field: keyword.  This is not used here but it must be
	     present.  */
	  while (sevlevel_var < end)
	    if (*sevlevel_var++ == ',')
	      break;

	  if (sevlevel_var < end)
	    {
	      /* Second field: severity level, a number.  */
	      char *cp;

	      level = strtol (sevlevel_var, &cp, 0);
	      if (cp != sevlevel_var && cp < end && *cp++ == ','
		  && level > MM_INFO)
		{
		  const char *new_string;

		  new_string = __strndup (cp, end - cp);

		  if (new_string != NULL
		      && (internal_addseverity (level, new_string)
			  != MM_OK))
		    free ((char *) new_string);
		}
	    }

	  sevlevel_var = end + (*end == ':' ? 1 : 0);
	}

      __libc_lock_unlock (lock);
    }
}


/* Add the new entry to the list.  */
static int
internal_addseverity (int severity, const char *string)
{
  struct severity_info *runp, *lastp;
  int result = MM_OK;

  /* First see if there is already a record for the severity level.  */
  for (runp = severity_list, lastp = NULL; runp != NULL; runp = runp->next)
    if (runp->severity == severity)
      break;
    else
      lastp = runp;

  if (runp != NULL)
    {
      if (string != NULL)
	/* Change the string.  */
	runp->string = string;
      else
	{
	  /* Remove the severity class.  */
	  if (lastp == NULL)
	    severity_list = runp->next;
	  else
	    lastp->next = runp->next;

	  free (runp);
	}
    }
  else if (string != NULL)
    {
      runp = malloc (sizeof (*runp));
      if (runp == NULL)
	result = MM_NOTOK;
      else
	{
	  runp->severity = severity;
	  runp->next = severity_list;
	  runp->string = string;
	  severity_list = runp;
	}
    }
  else
    /* We tried to remove a non-existing severity class.  */
    result = MM_NOTOK;

  return result;
}


/* Add new severity level or remove old one.  */
int
__addseverity (int severity, const char *string)
{
  int result;

  /* Prevent illegal SEVERITY values.  */
  if (severity <= MM_INFO)
    return MM_NOTOK;

  /* Protect the global data.  */
  __libc_lock_lock (lock);

  /* Do the real work.  */
  result = internal_addseverity (severity, string);

  /* Release the lock.  */
  __libc_lock_unlock (lock);

  return result;
}
weak_alias (__addseverity, addseverity)


void
__libc_fmtmsg_freemem (void)
{
  struct severity_info *runp = severity_list;

  while (runp != NULL)
    if (runp->severity > MM_INFO)
      {
	/* This is data we have to release.  */
	struct severity_info *here = runp;
	runp = runp->next;
	free (here);
      }
    else
      runp = runp->next;
}