pwdx.c: new usage & fix coding style

Coding style fixed and new help output.

Signed-off-by: Sami Kerola <kerolasa@iki.fi>

diff --git a/pwdx.c b/pwdx.c
index 755c17806f82b5bdedb8e7e892858bda3d6e4837..8edf8fb2a4ef46d1644ca8137384f268b4369f61 100644 (file)
--- a/pwdx.c
+++ b/pwdx.c
@@ -1,108 +1,105 @@
-// Copyright 2004 Nicholas Miell
-//
-// This file may be used subject to the terms and conditions of the
-// GNU Library General Public License Version 2 as published by the
-// Free Software Foundation.This program 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 Library General Public License for more
-// details.
+/*
+ * Copyright 2004 Nicholas Miell
+ *
+ * This file may be used subject to the terms and conditions of the
+ * GNU Library General Public License Version 2 as published by the
+ * Free Software Foundation.This program 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 Library General Public License for more
+ * details.
+ */
 
+#include <errno.h>
+#include <getopt.h>
+#include <limits.h>
 #include <stdio.h>
-#include <string.h>
 #include <stdlib.h>
+#include <string.h>
 #include <sys/types.h>
-#include <regex.h>
-#include <limits.h>
 #include <unistd.h>
-#include <errno.h>
 
 #include "proc/version.h"
 
-static void die(const char *msg) NORETURN;
-static void die(const char *msg)
+static void __attribute__ ((__noreturn__)) usage(FILE * out)
 {
-     fputs(msg, stderr);
-     exit(1);
-}
+       fprintf(out, "\nUsage:\n"
+               " %s [options] pid...\n", program_invocation_short_name);
+       fprintf(out,
+               "\nOptions:\n"
+               "  -V, --version      output version information and exit\n"
+               "  -h, --help         output help screen and exit\n\n");
 
-static void version(void) NORETURN;
-static void version(void)
-{
-     printf("pwdx (%s)\n", procps_version);
-     exit(0);
+       exit(out == stderr ? EXIT_FAILURE : EXIT_SUCCESS);
 }
 
-int main(int argc, char* argv[])
+int main(int argc, char *argv[])
 {
-     regex_t re;
-     int i;
-
-     if (argc < 2)
-          die("Usage: pwdx pid...\n");
-
-     // Allowed on the command line:
-     //
-     // --version
-     // -V
-     // /proc/nnnn
-     // nnnn
-     //
-     // where nnnn is any number that doesn't begin with 0.
-     //
-     // If --version or -V are present, further arguments are ignored
-     // completely.
-        
-     regcomp(&re, "^((/proc/+)?[1-9][0-9]*|-V|--version)$",
-             REG_EXTENDED|REG_NOSUB);
-
-     for (i = 1; i < argc; i++) {
-          if (regexec(&re, argv[i], 0, NULL, 0) != 0) {
-               /* Constant 27 is the length of the error string "pwdx: ... " */
-               char buf[27 + strlen (argv[i]) + 1];
-               snprintf(buf, sizeof buf, "pwdx: invalid process id: %s\n", argv[i]);
-               buf[sizeof(buf)-1] = '\0';
-               die(buf);
-          }
-          if (!strcmp("-V", argv[i]) || !strcmp("--version", argv[i]))
-               version();
-     }
-
-     regfree(&re);
-
-     int alloclen = 128;
-     char *pathbuf = malloc(alloclen);
-
-     for (i = 1; i < argc; i++) {
-          char * s;
-          int len;
-          /* Constant 10 is the length of strings "/proc/" + "/cwd" + 1 */
-          char buf[10 + strlen(argv[i]) + 1];
-          
-          // At this point, all arguments are in the form /proc/nnnn
-          // or nnnn, so a simple check based on the first char is
-          // possible
-          if (argv[i][0] != '/')
-               snprintf(buf, sizeof buf, "/proc/%s/cwd", argv[i]);
-          else
-               snprintf(buf, sizeof buf, "%s/cwd", argv[i]);
-
-          // buf contains /proc/nnnn/cwd symlink name on entry, the
-          // target of that symlink on return
-          while ((len = readlink(buf, pathbuf, alloclen)) == alloclen) {
-               alloclen *= 2;
-               pathbuf = realloc(pathbuf, alloclen);
-          }
-
-          if (len < 0) {
-               s = strerror(errno == ENOENT ? ESRCH : errno);
-          } else {
-               pathbuf[len] = 0;
-               s = pathbuf;
-          }
-
-          printf("%s: %s\n", argv[i], s);
-     }
-
-     return 0;
+       char ch;
+       int retval = 0, i;
+       int alloclen = 128;
+       char *pathbuf;
+
+       static const struct option longopts[] = {
+               {"version", no_argument, 0, 'V'},
+               {"help", no_argument, 0, 'h'},
+               {NULL, 0, 0, 0}
+       };
+
+       while ((ch = getopt_long(argc, argv, "Vh", longopts, NULL)) != -1)
+               switch (ch) {
+               case 'V':
+                       display_version();
+                       return EXIT_SUCCESS;
+               case 'h':
+                       usage(stdout);
+               default:
+                       usage(stderr);
+               }
+
+       argc -= optind;
+       argv += optind;
+
+       if (argc == 0)
+               usage(stderr);
+
+       pathbuf = malloc(alloclen);
+
+       for (i = 0; i < argc; i++) {
+               char *s;
+               ssize_t len;
+               /* Constant 10 is the length of strings "/proc/" + "/cwd" + 1 */
+               char buf[10 + strlen(argv[i]) + 1];
+
+               /*
+                * At this point, all arguments are in the form
+                * /proc/NNNN or NNNN, so a simple check based on
+                * the first char is possible
+                */
+               if (argv[i][0] != '/')
+                       snprintf(buf, sizeof buf, "/proc/%s/cwd", argv[i]);
+               else
+                       snprintf(buf, sizeof buf, "%s/cwd", argv[i]);
+
+               /*
+                * buf contains /proc/NNNN/cwd symlink name
+                * on entry, the target of that symlink on return
+                */
+               while ((len = readlink(buf, pathbuf, alloclen)) == alloclen) {
+                       alloclen *= 2;
+                       pathbuf = realloc(pathbuf, alloclen);
+               }
+
+               if (len < 0) {
+                       s = strerror(errno == ENOENT ? ESRCH : errno);
+                       retval = 1;
+               } else {
+                       pathbuf[len] = 0;
+                       s = pathbuf;
+               }
+
+               printf("%s: %s\n", argv[i], s);
+       }
+
+       return retval;
 }