Home | History | Annotate | Line # | Download | only in util 
      1 /*	$NetBSD: logwriter.c,v 1.3 2025/02/25 19:15:52 christos Exp $	*/
      2 
      3 /*++
      4 /* NAME
      5 /*	logwriter 3
      6 /* SUMMARY
      7 /*	logfile writer
      8 /* SYNOPSIS
      9 /*	#include <logwriter.h>
     10 /*
     11 /*	VSTREAM	*logwriter_open_or_die(
     12 /*	const char *path)
     13 /*
     14 /*	int	logwriter_write(
     15 /*	VSTREAM	*file,
     16 /*	const char *buffer.
     17 /*	ssize_t	buflen)
     18 /*
     19 /*	int	logwriter_close(
     20 /*	VSTREAM	*file)
     21 /*
     22 /*	int	logwriter_one_shot(
     23 /*	const char *path,
     24 /*	const char *buffer,
     25 /*	ssize_t	buflen)
     26 /*
     27 /*	int	set_logwriter_create_perms(
     28 /*	const char *mode)
     29 /* DESCRIPTION
     30 /*	This module manages a logfile writer.
     31 /*
     32 /*	logwriter_open_or_die() safely opens the specified file in
     33 /*	write+append mode. File open/create errors are fatal.
     34 /*
     35 /*	logwriter_write() writes the buffer plus newline to the
     36 /*	open logfile. The result is zero if successful, VSTREAM_EOF
     37 /*	if the operation failed.
     38 /*
     39 /*	logwriter_close() closes the logfile and destroys the VSTREAM
     40 /*	instance. The result is zero if there were no errors writing
     41 /*	the file, VSTREAM_EOF otherwise.
     42 /*
     43 /*	logwriter_one_shot() combines all the above operations. The
     44 /*	result is zero if successful, VSTREAM_EOF if any operation
     45 /*	failed.
     46 /*
     47 /*	set_logwriter_create_perms() sets the file permissions that
     48 /*	will be used when creating a logfile. Valid inputs are
     49 /*	"644", "640", and "600". Leading zeros are allowed and
     50 /*	ignored.
     51 /* DIAGNOSTICS
     52 /*	Fatal error: logfile create error; warning: logfile permission
     53 /*	change error. set_logwriter_create_perms() returns the file
     54 /*	create permission if the request is valid, -1 otherwise.
     55 /* LICENSE
     56 /* .ad
     57 /* .fi
     58 /*	The Secure Mailer license must be distributed with this software.
     59 /* AUTHOR(S)
     60 /*	Wietse Venema
     61 /*	Google, Inc.
     62 /*	111 8th Avenue
     63 /*	New York, NY 10011, USA
     64 /*--*/
     65 
     66  /*
     67   * System library.
     68   */
     69 #include <sys_defs.h>
     70 #include <unistd.h>
     71 #include <string.h>
     72 #include <errno.h>
     73 
     74  /*
     75   * Utility library.
     76   */
     77 #include <iostuff.h>
     78 #include <logwriter.h>
     79 #include <msg.h>
     80 #include <mymalloc.h>
     81 #include <safe_open.h>
     82 #include <vstream.h>
     83 #include <name_code.h>
     84 
     85  /*
     86   * Application-specific.
     87   */
     88 static int logwriter_perms = 0600;
     89 
     90 /* logwriter_open_or_die - open logfile */
     91 
     92 VSTREAM *logwriter_open_or_die(const char *path)
     93 {
     94     VSTREAM *fp;
     95     VSTRING *why = vstring_alloc(100);
     96 
     97 #define NO_STATP	((struct stat *) 0)
     98 #define NO_CHOWN	(-1)
     99 #define NO_CHGRP	(-1)
    100 
    101     fp = safe_open(path, O_CREAT | O_WRONLY | O_APPEND, logwriter_perms,
    102 		   NO_STATP, NO_CHOWN, NO_CHGRP, why);
    103     if (fp == 0)
    104 	msg_fatal("open logfile '%s': %s", path, vstring_str(why));
    105     close_on_exec(vstream_fileno(fp), CLOSE_ON_EXEC);
    106     vstring_free(why);
    107     return (fp);
    108 }
    109 
    110 /* logwriter_write - append to logfile */
    111 
    112 int     logwriter_write(VSTREAM *fp, const char *buf, ssize_t len)
    113 {
    114     if (len < 0)
    115 	msg_panic("logwriter_write: negative length %ld", (long) len);
    116     if (vstream_fwrite(fp, buf, len) != len)
    117 	return (VSTREAM_EOF);
    118     VSTREAM_PUTC('\n', fp);
    119     return (vstream_fflush(fp));
    120 }
    121 
    122 /* logwriter_close - close logfile */
    123 
    124 int     logwriter_close(VSTREAM *fp)
    125 {
    126     return (vstream_fclose(fp));
    127 }
    128 
    129 /* logwriter_one_shot - one-shot logwriter */
    130 
    131 int     logwriter_one_shot(const char *path, const char *buf, ssize_t len)
    132 {
    133     VSTREAM *fp;
    134     int     err;
    135 
    136     fp = logwriter_open_or_die(path);
    137     err = logwriter_write(fp, buf, len);
    138     err |= logwriter_close(fp);
    139     return (err ? VSTREAM_EOF : 0);
    140 }
    141 
    142 /* set_logwriter_create_perms - logfile permission control */
    143 
    144 int     set_logwriter_create_perms(const char *mode_str)
    145 {
    146     static const NAME_CODE sane_perms[] = {
    147 	"644", 0644,
    148 	"640", 0640,
    149 	"600", 0600,
    150 	0, -1,
    151     };
    152     int     perms;
    153 
    154     if ((perms = name_code(sane_perms, NAME_CODE_FLAG_NONE,
    155 			   mode_str + strspn(mode_str, "0"))) != -1)
    156 	logwriter_perms = perms;
    157     return (perms);
    158 }
    159