libpwdgrp: can't depend on strlen(line_buff) != 0

function                                             old     new   delta
bb__pgsreader                                        188     202     +14

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 42 insertions, 40 deletions

diff --git a/libpwdgrp/pwd_grp.c b/libpwdgrp/pwd_grp.c
index 947f48d43..5b0d6b245 100644
--- a/libpwdgrp/pwd_grp.c
+++ b/libpwdgrp/pwd_grp.c
@@ -19,7 +19,6 @@
  */
 
 #include "libbb.h"
-//#include <features.h>
 #include <assert.h>
 
 #ifndef _PATH_SHADOW
@@ -1000,7 +999,6 @@ static int bb__parsespent(void *data, char *line)
                         if (*endptr != ':') {
                                 break;
                         }
-
                 }
 
                 *line++ = '\0';
@@ -1022,56 +1020,60 @@ static int bb__parsespent(void *data, char *line)
 static int bb__pgsreader(int (*parserfunc)(void *d, char *line), void *data,
                                 char *__restrict line_buff, size_t buflen, FILE *f)
 {
-        int line_len;
         int skip;
         int rv = ERANGE;
 
         if (buflen < PWD_BUFFER_SIZE) {
                 errno = rv;
-        } else {
-                skip = 0;
-                do {
-                        if (!fgets(line_buff, buflen, f)) {
-                                if (feof(f)) {
-                                        rv = ENOENT;
-                                }
-                                break;
-                        }
+                return rv;
+        }
 
-                        line_len = strlen(line_buff) - 1; /* strlen() must be > 0. */
-                        if (line_buff[line_len] == '\n') {
-                                line_buff[line_len] = 0;
-                        } else if (line_len + 2 == buflen) { /* line too long */
-                                ++skip;
-                                continue;
+        skip = 0;
+        while (1) {
+                if (!fgets(line_buff, buflen, f)) {
+                        if (feof(f)) {
+                                rv = ENOENT;
                         }
+                        break;
+                }
 
-                        if (skip) {
-                                --skip;
+                {
+                        int line_len = strlen(line_buff) - 1;
+                        if (line_len >= 0 && line_buff[line_len] == '\n') {
+                                line_buff[line_len] = '\0';
+                        } else
+                        if (line_len + 2 == buflen) {
+                                /* A start (or continuation) of overlong line */
+                                skip = 1;
                                 continue;
-                        }
+                        } /* else: a last line in the file, and it has no '\n' */
+                }
 
-                        /* NOTE: glibc difference - glibc strips leading whitespace from
-                         * records.  We do not allow leading whitespace. */
-
-                        /* Skip empty lines, comment lines, and lines with leading
-                         * whitespace. */
-                        if (*line_buff && (*line_buff != '#') && !isspace(*line_buff)) {
-                                if (parserfunc == bb__parsegrent) {     /* Do evil group hack. */
-                                        /* The group entry parsing function needs to know where
-                                         * the end of the buffer is so that it can construct the
-                                         * group member ptr table. */
-                                        ((struct group *) data)->gr_name = line_buff + buflen;
-                                }
+                if (skip) {
+                        /* This "line" is a remainder of overlong line, ignore */
+                        skip = 0;
+                        continue;
+                }
 
-                                if (!parserfunc(data, line_buff)) {
-                                        rv = 0;
-                                        break;
-                                }
+                /* NOTE: glibc difference - glibc strips leading whitespace from
+                 * records.  We do not allow leading whitespace. */
+
+                /* Skip empty lines, comment lines, and lines with leading
+                 * whitespace. */
+                if (line_buff[0] != '\0' && line_buff[0] != '#' && !isspace(line_buff[0])) {
+                        if (parserfunc == bb__parsegrent) {
+                                /* Do evil group hack:
+                                 * The group entry parsing function needs to know where
+                                 * the end of the buffer is so that it can construct the
+                                 * group member ptr table. */
+                                ((struct group *) data)->gr_name = line_buff + buflen;
                         }
-                } while (1);
-
-        }
+                        if (parserfunc(data, line_buff) == 0) {
+                                rv = 0;
+                                break;
+                        }
+                }
+        } /* while (1) */
 
         return rv;
 }