Changeset 587867a in mainline for uspace/app/bdsh/exec.c

Timestamp:

2019-03-16T13:01:30Z (5 years ago)

Author:

Matthieu Riolo <matthieu.riolo@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

aeeaf0f

Parents:

1c481ee

Message:

improve error handling

The code did not test if malloc returned NULL.
This meant that the code potentially could break without
that the user was informed.

File:

• uspace/app/bdsh/exec.c (modified) (3 diffs)

uspace/app/bdsh/exec.c

@@ -47 +47 @@
 #include "errors.h"
 
-static char *find_command(char *);
+static errno_t find_command(char *, char **);
 static int try_access(const char *);
 
@@ -65 +65 @@
 }
 
-/** Returns the full path of "cmd" if cmd is found
+/** Returns EOK if no internal failure or else ENOMEM
  *
- * else just hand back cmd as it was presented
+ * When the parameter `cmd` can be found then the absolute path will be set in `found`.
+ * Or else `found` will be NULL.
+ * `found` will be newly allocated and must be freed by the caller
  */
-static char *find_command(char *cmd)
+static errno_t find_command(char *cmd, char **found)
 {
         /* The user has specified a full or relative path, just give it back. */
         if (is_path(cmd)) {
                 if (-1 != try_access(cmd)) {
-                        return str_dup(cmd);
+                        *found = str_dup(cmd);
+                        return EOK;
+                }
+
+                *found = NULL;
+                return EOK;
+        }
+
+        *found = (char *)malloc(PATH_MAX);
+        if (*found == NULL) {
+                return ENOMEM;
+        }
+
+        /* We now have n places to look for the command */
+        size_t i;
+        size_t cmd_length = str_length(cmd);
+        for (i = 0; search_dir[i] != NULL; i++) {
+                if (str_length(search_dir[i]) + cmd_length + 2 > PATH_MAX) {
+                        free(*found);
+                        return ENOMEM;
+                }
+
+                memset(*found, 0, PATH_MAX);
+                snprintf(*found, PATH_MAX, "%s/%s", search_dir[i], cmd);
+                if (-1 != try_access(*found)) {
+                        return EOK;
                 }
         }
+        free(*found);
+        *found = NULL;
 
-        char *found = (char *)malloc(PATH_MAX);
-        /* We now have n places to look for the command */
-        size_t i;
-        for (i = 0; search_dir[i] != NULL; i++) {
-                memset(found, 0, PATH_MAX);
-                snprintf(found, PATH_MAX, "%s/%s", search_dir[i], cmd);
-                if (-1 != try_access(found)) {
-                        return (char *) found;
-                }
-        }
-        free(found);
-
-        /* We didn't find it, just give it back as-is. */
-        return str_dup(cmd);
+        /* We didn't find it, return NULL */
+        return EOK;
 }
 
@@ -105 +122 @@
         FILE *files[3];
 
-        tmp = find_command(cmd);
+        rc = find_command(cmd, &tmp);
+        if (rc != EOK) {
+                cli_error(CL_ENOMEM, "%s: failure executing find_command()", progname);
+                return 1;
+        }
+
+        if (tmp == NULL) {
+                cli_error(CL_EEXEC, "%s: Command not found '%s'", progname, cmd);
+                return 1;
+        }
 
         files[0] = io->stdin;