svn commit: r293463 - stable/10/lib/libc/gen

[Ravi Pokala]

Author: rpokala
Date: Sat Jan  9 05:05:15 2016
New Revision: 293463
URL: https://svnweb.freebsd.org/changeset/base/293463

Log:
  MFC r291114: popen() requires check for fdopen() failure
  
  Move fdopen() up near other resource allocation like malloc(); do proper
  deallocation on failure later on in the function.
  
  Approved by:  jhb
  Sponsored by: Panasas, Inc.

Modified:
  stable/10/lib/libc/gen/popen.c
Directory Properties:
  stable/10/   (props changed)

Modified: stable/10/lib/libc/gen/popen.c
==============================================================================
--- stable/10/lib/libc/gen/popen.c      Sat Jan  9 05:02:35 2016        
(r293462)
+++ stable/10/lib/libc/gen/popen.c      Sat Jan  9 05:05:15 2016        
(r293463)
@@ -73,6 +73,7 @@ popen(command, type)
        struct pid *cur;
        FILE *iop;
        int pdes[2], pid, twoway, cloexec;
+       int pdes_unused_in_parent;
        char *argv[4];
        struct pid *p;
 
@@ -99,6 +100,20 @@ popen(command, type)
                return (NULL);
        }
 
+       if (*type == 'r') {
+               iop = fdopen(pdes[0], type);
+               pdes_unused_in_parent = pdes[1];
+       } else {
+               iop = fdopen(pdes[1], type);
+               pdes_unused_in_parent = pdes[0];
+       }
+       if (iop == NULL) {
+               (void)_close(pdes[0]);
+               (void)_close(pdes[1]);
+               free(cur);
+               return (NULL);
+       }
+
        argv[0] = "sh";
        argv[1] = "-c";
        argv[2] = (char *)command;
@@ -108,9 +123,14 @@ popen(command, type)
        switch (pid = vfork()) {
        case -1:                        /* Error. */
                THREAD_UNLOCK();
-               (void)_close(pdes[0]);
-               (void)_close(pdes[1]);
+               /*
+                * The _close() closes the unused end of pdes[], while
+                * the fclose() closes the used end of pdes[], *and* cleans
+                * up iop.
+                */
+               (void)_close(pdes_unused_in_parent);
                free(cur);
+               (void)fclose(iop);
                return (NULL);
                /* NOTREACHED */
        case 0:                         /* Child. */
@@ -155,14 +175,8 @@ popen(command, type)
        }
        THREAD_UNLOCK();
 
-       /* Parent; assume fdopen can't fail. */
-       if (*type == 'r') {
-               iop = fdopen(pdes[0], type);
-               (void)_close(pdes[1]);
-       } else {
-               iop = fdopen(pdes[1], type);
-               (void)_close(pdes[0]);
-       }
+       /* Parent. */
+       (void)_close(pdes_unused_in_parent);
 
        /* Link into list of file descriptors. */
        cur->fp = iop;
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