Fix environment modification code

Port fixes from rush

1 files changed, 55 insertions, 34 deletions

diff --git a/src/environ.c b/src/environ.c
index 659b724..eb22fbd 100644
--- a/src/environ.c
+++ b/src/environ.c
@@ -29,34 +29,45 @@ extern char **environ;    /* Environment */
         }                                                       \
         } while (0)
 
-static char *
-find_env(const char *name, int val)
+static int
+find_env_pos(char **env, char *name, size_t *idx, size_t *valoff)
 {
-        if (environ) {
-                int nlen = strcspn(name, "+=");
-                int i;
-
-                for (i = 0; environ[i]; i++) {
-                        size_t elen = strcspn(environ[i], "=");
-                        if (elen == nlen &&
-                            memcmp(name, environ[i], nlen) == 0)
-                                return val ? environ[i] + elen + 1 : environ[i];
+        size_t nlen = strcspn(name, "+=");
+        size_t i;
+
+        for (i = 0; env[i]; i++) {
+                size_t elen = strcspn(env[i], "=");
+                if (elen == nlen && memcmp(name, env[i], nlen) == 0) {
+                        if (idx)
+                                *idx = i;
+                        if (valoff)
+                                *valoff = elen + 1;
+                        return 0;
                 }
-        }
-        return NULL;
+        }
+        return -1;
+}
+
+static char *
+find_env_ptr(char **env, char *name, int val)
+{
+        size_t i, j;
+        if (find_env_pos(env, name, &i, &j))
+                return NULL;
+        return val ? env[i] + j : env[i];
 }
 
 static int
-locate_unset(char **env, const char *name)
+var_is_unset(char **env, const char *name)
 {
         int i;
         int nlen = strcspn(name, "=");
 
         for (i = 0; env[i]; i++) {
                 if (env[i][0] == '-') {
-                        size_t elen = strcspn (env[i] + 1, "=");
+                        size_t elen = strcspn(env[i] + 1, "=");
                         if (elen == nlen &&
-                            memcmp (name, env[i] + 1, nlen) == 0) {
+                            memcmp(name, env[i] + 1, nlen) == 0) {
                                 if (env[i][nlen + 1])
                                         return strcmp(name + nlen,
                                                       env[i] + 1 + nlen) == 0;
@@ -77,7 +88,7 @@ env_concat(const char *name, size_t namelen, const char *a, const char *b)
         if (a && b) {
                 res = emalloc(namelen + 1 + strlen(a) + strlen(b) + 1);
                 strcpy(res + namelen + 1, a);
-                strcat(res, b);
+                strcat(res + namelen + 1, b);
         } else if (a) {
                 len = strlen(a);
                 if (ispunct(a[len-1]))
@@ -115,7 +126,7 @@ environ_setup(char **hint, char **kve)
         char **new_env;
         char **addenv = defenv;
         char *var;
-        size_t count, i, n;
+        size_t count, i, j, n;
         struct wordsplit ws;
         int wsflags = WRDSF_NOCMD | WRDSF_QUOTE | WRDSF_NOSPLIT |
                       WRDSF_ENV | WRDSF_ENV_KV;
@@ -154,12 +165,12 @@ environ_setup(char **hint, char **kve)
   
         if (old_env)
                 for (i = 0; old_env[i]; i++) {
-                        if (!locate_unset(hint, old_env[i]))
+                        if (!var_is_unset(hint, old_env[i]))
                                 new_env[n++] = old_env[i];
                 }
 
         for (i = 0; addenv[i]; i++)
-                if (!locate_unset(hint, addenv[i])) {
+                if (!var_is_unset(hint, addenv[i])) {
                         if (wordsplit(addenv[i], &ws, wsflags)) {
                                 diag(LOG_CRIT, "wordsplit: %s",
                                      wordsplit_strerror(&ws));
@@ -185,26 +196,36 @@ environ_setup(char **hint, char **kve)
                 wsflags |= WRDSF_REUSE;
                 var = ws.ws_wordv[0];
                 
+                /* Find the slot for the variable.  Use next available
+                   slot if there's no such variable in new_env */
+                if (find_env_pos(new_env, hint[i], &j, NULL))
+                        j = n;
+                        
                 if ((p = strchr(var, '='))) {
                         if (p == var)
                                 continue; /* Ignore erroneous entry */
+
                         if (p[-1] == '+') 
-                                new_env[n++] = env_concat(var,
-                                                          p - var - 1,
-                                                          find_env(var, 1),
-                                                          p + 1);
+                                new_env[j] = env_concat(var,
+                                                        p - var - 1,
+                                                        find_env_ptr(environ,
+                                                                     var, 1),
+                                                        p + 1);
                         else if (p[1] == '+')
-                                new_env[n++] = env_concat(var,
-                                                          p - var,
-                                                          p + 2,
-                                                          find_env(var, 1));
+                                new_env[j] = env_concat(var,
+                                                        p - var,
+                                                        p + 2,
+                                                        find_env_ptr(environ,
+                                                                     var, 1));
                         else
-                                new_env[n++] = estrdup(var);
-                } else {
-                        p = find_env(var, 0);
-                        if (p)
-                                new_env[n++] = p;
-                }
+                                new_env[j] = estrdup(var);
+                } else if ((p = find_env_ptr(environ, hint[i], 0)))
+                        new_env[j] = p;
+                else
+                        continue;
+                /* Adjust environment size */
+                if (j == n)
+                        ++n;
         }
         if (self_test_pid) {
                 char buf[512];