Date: Fri, 19 Jun 2015 22:24:59 +0000 (UTC) From: Maxim Sobolev <sobomax@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r284614 - head/sys/boot/uboot/lib Message-ID: <201506192224.t5JMOxpC097306@svn.freebsd.org>
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Author: sobomax Date: Fri Jun 19 22:24:58 2015 New Revision: 284614 URL: https://svnweb.freebsd.org/changeset/base/284614 Log: Provide bug4bug workaround for certain dumbiness of the u-boot's API_env_enum function, which is expected to set returned env to NULL upon reaching the end of the environment list but fails to do so in certain cases. The respective u-boot code looks like the following (HEAD at the time of this commit): --- api.c --- 496 static int API_env_enum(va_list ap) ... 510 *next = last; 511 512 for (i = 0; env_get_char(i) != '\0'; i = n + 1) { 513 for (n = i; env_get_char(n) != '\0'; ++n) { 514 if (n >= CONFIG_ENV_SIZE) { 515 /* XXX shouldn't we set *next = NULL?? */ 516 return 0; 517 } 518 } ------------- The net result is that any unfortunate user of the loader's ub_env_enum() function hitting this condition would be trapped in the infinite loop, as the main use pattern of ub_env_enum() is basically the following: while ((env = ub_env_enum(env)) != NULL) { DO STUFF } Which would stuck forever with the last element. Modified: head/sys/boot/uboot/lib/glue.c Modified: head/sys/boot/uboot/lib/glue.c ============================================================================== --- head/sys/boot/uboot/lib/glue.c Fri Jun 19 21:55:12 2015 (r284613) +++ head/sys/boot/uboot/lib/glue.c Fri Jun 19 22:24:58 2015 (r284614) @@ -513,7 +513,7 @@ ub_env_enum(const char *last) if (!syscall(API_ENV_ENUM, NULL, (uint32_t)last, (uint32_t)&env)) return (NULL); - if (env == NULL) + if (env == NULL || last == env) /* no more env. variables to enumerate */ return (NULL);
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