*: tweak error messages

sysctl: shrink; support recursing if name is a directory:
 "sysctl net.ipv4.conf". Patch by xmaks AT email.cz

   text    data     bss     dec     hex filename
 793659     504    7492  801655   c3b77 busybox_old
 793576     504    7492  801572   c3b24 busybox_unstripped

1 files changed, 131 insertions, 141 deletions

diff --git a/procps/sysctl.c b/procps/sysctl.c
index 860c84062..23fb16e9e 100644
--- a/procps/sysctl.c
+++ b/procps/sysctl.c
@@ -16,19 +16,11 @@
 
 #include "libbb.h"
 
-static int sysctl_read_setting(const char *setting);
-static int sysctl_write_setting(const char *setting);
+static int sysctl_act_on_setting(char *setting);
 static int sysctl_display_all(const char *path);
-static int sysctl_preload_file_and_exit(const char *filename);
+static int sysctl_handle_preload_file(const char *filename);
 static void sysctl_dots_to_slashes(char *name);
 
-static const char ETC_SYSCTL_CONF[] ALIGN1 = "/etc/sysctl.conf";
-static const char PROC_SYS[] ALIGN1 = "/proc/sys/";
-enum { strlen_PROC_SYS = sizeof(PROC_SYS) - 1 };
-
-static const char msg_unknown_key[] ALIGN1 =
-        "error: '%s' is an unknown key";
-
 static void dwrite_str(int fd, const char *buf)
 {
         write(fd, buf, strlen(buf));
@@ -52,212 +44,209 @@ int sysctl_main(int argc UNUSED_PARAM, char **argv)
         opt = getopt32(argv, "+neAapw"); /* '+' - stop on first non-option */
         argv += optind;
         opt ^= (FLAG_SHOW_KEYS | FLAG_SHOW_KEY_ERRORS);
-        option_mask32 ^= (FLAG_SHOW_KEYS | FLAG_SHOW_KEY_ERRORS);
+        option_mask32 = opt;
 
-        if (opt & (FLAG_TABLE_FORMAT | FLAG_SHOW_ALL))
-                return sysctl_display_all(PROC_SYS);
-        if (opt & FLAG_PRELOAD_FILE)
-                return sysctl_preload_file_and_exit(*argv ? *argv : ETC_SYSCTL_CONF);
+        if (opt & FLAG_PRELOAD_FILE) {
+                option_mask32 |= FLAG_WRITE;
+                /* xchdir("/proc/sys") is inside */
+                return sysctl_handle_preload_file(*argv ? *argv : "/etc/sysctl.conf");
+        }
+        xchdir("/proc/sys");
+        /* xchroot(".") - if you are paranoid */
+        if (opt & (FLAG_TABLE_FORMAT | FLAG_SHOW_ALL)) {
+                return sysctl_display_all(".");
+        }
 
         retval = 0;
         while (*argv) {
-                if (opt & FLAG_WRITE)
-                        retval |= sysctl_write_setting(*argv);
-                else
-                        retval |= sysctl_read_setting(*argv);
+                sysctl_dots_to_slashes(*argv);
+                retval |= sysctl_display_all(*argv);
                 argv++;
         }
 
         return retval;
-} /* end sysctl_main() */
+}
 
 /* Set sysctl's from a conf file. Format example:
  * # Controls IP packet forwarding
  * net.ipv4.ip_forward = 0
  */
-static int sysctl_preload_file_and_exit(const char *filename)
+static int sysctl_handle_preload_file(const char *filename)
 {
         char *token[2];
         parser_t *parser;
 
         parser = config_open(filename);
+        /* Must do it _after_ config_open(): */
+        xchdir("/proc/sys");
+        /* xchroot(".") - if you are paranoid */
+
 // TODO: ';' is comment char too
         while (config_read(parser, token, 2, 2, "# \t=", PARSE_NORMAL)) {
-#if 0
-                char *s = xasprintf("%s=%s", token[0], token[1]);
-                sysctl_write_setting(s);
-                free(s);
-#else /* Save ~4 bytes by using parser internals */
-                sprintf(parser->line, "%s=%s", token[0], token[1]); // must have room by definition
-                sysctl_write_setting(parser->line);
-#endif
+                /* Save ~4 bytes by using parser internals */
+                /* parser->line is big enough for sprintf */
+                sprintf(parser->line, "%s=%s", token[0], token[1]);
+                sysctl_dots_to_slashes(parser->line);
+                sysctl_display_all(parser->line);
         }
         if (ENABLE_FEATURE_CLEAN_UP)
                 config_close(parser);
         return 0;
-} /* end sysctl_preload_file_and_exit() */
+}
 
-static int sysctl_write_setting(const char *setting)
+static int sysctl_act_on_setting(char *setting)
 {
-        int retval;
-        const char *name;
-        const char *value;
-        const char *equals;
-        char *tmpname, *outname, *cptr;
-        int fd;
+        int fd, retval = EXIT_SUCCESS;
+        char *cptr, *outname, *value;
 
-        name = setting;
-        equals = strchr(setting, '=');
-        if (!equals) {
-                bb_error_msg("error: '%s' must be of the form name=value", setting);
-                return EXIT_FAILURE;
-        }
+        outname = xstrdup(setting);
 
-        value = equals + 1;     /* point to the value in name=value */
-        if (name == equals || !*value) {
-                bb_error_msg("error: malformed setting '%s'", setting);
-                return EXIT_FAILURE;
+        cptr = outname;
+        while (*cptr) {
+                if (*cptr == '/')
+                        *cptr = '.';
+                cptr++;
         }
 
-        tmpname = xasprintf("%s%.*s", PROC_SYS, (int)(equals - name), name);
-        outname = xstrdup(tmpname + strlen_PROC_SYS);
-
-        sysctl_dots_to_slashes(tmpname);
-
-        while ((cptr = strchr(outname, '/')) != NULL)
-                *cptr = '.';
+        if (option_mask32 & FLAG_WRITE) {
+                cptr = strchr(setting, '=');
+                if (cptr == NULL) {
+                        bb_error_msg("error: '%s' must be of the form name=value",
+                                outname);
+                        retval = EXIT_FAILURE;
+                        goto end;
+                }
+                value = cptr + 1;       /* point to the value in name=value */
+                if (setting == cptr || !*value) {
+                        bb_error_msg("error: malformed setting '%s'", outname);
+                        retval = EXIT_FAILURE;
+                        goto end;
+                }
+                *cptr = '\0';
+                fd = open(setting, O_WRONLY|O_CREAT|O_TRUNC, 0666);
+        } else {
+                fd = open(setting, O_RDONLY);
+        }
 
-        fd = open(tmpname, O_WRONLY | O_CREAT | O_TRUNC, 0666);
         if (fd < 0) {
                 switch (errno) {
                 case ENOENT:
                         if (option_mask32 & FLAG_SHOW_KEY_ERRORS)
-                                bb_error_msg(msg_unknown_key, outname);
+                                bb_error_msg("error: '%s' is an unknown key", outname);
                         break;
                 default:
-                        bb_perror_msg("error setting key '%s'", outname);
+                        bb_perror_msg("error %sing key '%s'",
+                                        option_mask32 & FLAG_WRITE ?
+                                                "sett" : "read",
+                                        outname);
                         break;
                 }
                 retval = EXIT_FAILURE;
-        } else {
+                goto end;
+        }
+
+        if (option_mask32 & FLAG_WRITE) {
                 dwrite_str(fd, value);
                 close(fd);
-                if (option_mask32 & FLAG_SHOW_KEYS) {
+                if (option_mask32 & FLAG_SHOW_KEYS)
                         printf("%s = ", outname);
-                }
                 puts(value);
-                retval = EXIT_SUCCESS;
-        }
-
-        free(tmpname);
-        free(outname);
-        return retval;
-} /* end sysctl_write_setting() */
-
-static int sysctl_read_setting(const char *name)
-{
-        int retval;
-        char *tmpname, *outname, *cptr;
-        char inbuf[1025];
-        FILE *fp;
-
-        if (!*name) {
-                if (option_mask32 & FLAG_SHOW_KEY_ERRORS)
-                        bb_error_msg(msg_unknown_key, name);
-                return -1;
-        }
-
-        tmpname = concat_path_file(PROC_SYS, name);
-        outname = xstrdup(tmpname + strlen_PROC_SYS);
-
-        sysctl_dots_to_slashes(tmpname);
-
-        while ((cptr = strchr(outname, '/')) != NULL)
-                *cptr = '.';
+        } else {
+                char c;
 
-        fp = fopen_for_read(tmpname);
-        if (fp == NULL) {
-                switch (errno) {
-                case ENOENT:
-                        if (option_mask32 & FLAG_SHOW_KEY_ERRORS)
-                                bb_error_msg(msg_unknown_key, outname);
-                        break;
-                default:
+                value = cptr = xmalloc_read(fd, NULL);
+                close(fd);
+                if (value == NULL) {
                         bb_perror_msg("error reading key '%s'", outname);
-                        break;
+                        goto end;
                 }
-                retval = EXIT_FAILURE;
-        } else {
-                while (fgets(inbuf, sizeof(inbuf) - 1, fp)) {
-                        if (option_mask32 & FLAG_SHOW_KEYS) {
+
+                /* dev.cdrom.info and sunrpc.transports, for example,
+                 * are multi-line. Try "sysctl sunrpc.transports"
+                 */
+                while ((c = *cptr) != '\0') {
+                        if (option_mask32 & FLAG_SHOW_KEYS)
                                 printf("%s = ", outname);
+                        while (1) {
+                                fputc(c, stdout);
+                                cptr++;
+                                if (c == '\n')
+                                        break;
+                                c = *cptr;
+                                if (c == '\0')
+                                        break;
                         }
-                        fputs(inbuf, stdout);
                 }
-                fclose(fp);
-                retval = EXIT_SUCCESS;
+                free(value);
         }
-
-        free(tmpname);
+ end:
         free(outname);
         return retval;
-} /* end sysctl_read_setting() */
+}
 
 static int sysctl_display_all(const char *path)
 {
-        int retval = EXIT_SUCCESS;
-        DIR *dp;
-        struct dirent *de;
-        char *tmpdir;
-        struct stat ts;
-
-        dp = opendir(path);
-        if (!dp) {
-                return EXIT_FAILURE;
-        }
-        while ((de = readdir(dp)) != NULL) {
-                tmpdir = concat_subpath_file(path, de->d_name);
-                if (tmpdir == NULL)
-                        continue; /* . or .. */
-                if (stat(tmpdir, &ts) != 0) {
-                        bb_perror_msg(tmpdir);
-                } else if (S_ISDIR(ts.st_mode)) {
-                        retval |= sysctl_display_all(tmpdir);
-                } else {
-                        retval |= sysctl_read_setting(tmpdir + strlen_PROC_SYS);
+        DIR *dirp;
+        struct stat buf;
+        struct dirent *entry;
+        char *next;
+        int retval = 0;
+
+        stat(path, &buf);
+        if (S_ISDIR(buf.st_mode) && !(option_mask32 & FLAG_WRITE)) {
+                dirp = opendir(path);
+                if (dirp == NULL)
+                        return -1;
+                while ((entry = readdir(dirp)) != NULL) {
+                        next = concat_subpath_file(
+                                path, entry->d_name);
+                        if (next == NULL)
+                                continue; /* d_name is "." or ".." */
+                        /* if path was ".", drop "./" prefix: */
+                        retval |= sysctl_display_all((next[0] == '.' && next[1] == '/') ?
+                                            next + 2 : next);
+                        free(next);
                 }
-                free(tmpdir);
-        } /* end while */
-        closedir(dp);
+                closedir(dirp);
+        } else {
+                char *name = xstrdup(path);
+                retval |= sysctl_act_on_setting(name);
+                free(name);
+        }
 
         return retval;
-} /* end sysctl_display_all() */
+}
 
 static void sysctl_dots_to_slashes(char *name)
 {
         char *cptr, *last_good, *end;
 
-        /* It can be good as-is! */
-        if (access(name, F_OK) == 0)
-                return;
-
-        /* Example from bug 3894:
+        /* Convert minimum number of '.' to '/' so that
+         * we end up with existing file's name.
+         *
+         * Example from bug 3894:
          * net.ipv4.conf.eth0.100.mc_forwarding ->
-         * net/ipv4/conf/eth0.100/mc_forwarding. NB:
-         * net/ipv4/conf/eth0/mc_forwarding *also exists*,
+         * net/ipv4/conf/eth0.100/mc_forwarding
+         * NB: net/ipv4/conf/eth0/mc_forwarding *also exists*,
          * therefore we must start from the end, and if
          * we replaced even one . -> /, start over again,
          * but never replace dots before the position
-         * where replacement occurred. */
-        end = name + strlen(name) - 1;
+         * where last replacement occurred.
+         */
+        end = name + strlen(name);
         last_good = name - 1;
+        *end = '.'; /* trick the loop in trying full name too */
+
  again:
         cptr = end;
         while (cptr > last_good) {
                 if (*cptr == '.') {
                         *cptr = '\0';
+                        //bb_error_msg("trying:'%s'", name);
                         if (access(name, F_OK) == 0) {
                                 *cptr = '/';
+                                *end = '\0'; /* prevent trailing '/' */
+                                //bb_error_msg("replaced:'%s'", name);
                                 last_good = cptr;
                                 goto again;
                         }
@@ -265,4 +254,5 @@ static void sysctl_dots_to_slashes(char *name)
                 }
                 cptr--;
         }
-} /* end sysctl_dots_to_slashes() */
+        *end = '\0';
+}