linux-user: Add generic env variable handling
Adds support for qemu to modify target process environment variables using -E and -U commandline switches. This replaces eventually the -drop-ld-preload flag. Signed-off-by: Aurelien Jarno <aurelien@aurel32.net> Signed-off-by: Riku Voipio <riku.voipio@iki.fi> git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6484 c046a42c-6fe2-441c-8c8c-71466251a162
This commit is contained in:
aurel32
parent
e1ce5e400a
commit
04a6dfebb6
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@ -320,7 +320,7 @@ CFLAGS+=-p
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endif
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OBJS= main.o syscall.o strace.o mmap.o signal.o path.o thunk.o \
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elfload.o linuxload.o uaccess.o
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elfload.o linuxload.o uaccess.o envlist.o
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LIBS+= $(AIOLIBS)
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ifdef TARGET_HAS_BFLT
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OBJS+= flatload.o
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@ -0,0 +1,247 @@
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#include <sys/queue.h>
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#include <assert.h>
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#include <errno.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include "envlist.h"
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struct envlist_entry {
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const char *ev_var; /* actual env value */
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LIST_ENTRY(envlist_entry) ev_link;
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};
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struct envlist {
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LIST_HEAD(, envlist_entry) el_entries; /* actual entries */
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size_t el_count; /* number of entries */
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};
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static int envlist_parse(envlist_t *envlist,
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const char *env, int (*)(envlist_t *, const char *));
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/*
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* Allocates new envlist and returns pointer to that or
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* NULL in case of error.
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*/
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envlist_t *
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envlist_create(void)
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{
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envlist_t *envlist;
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if ((envlist = malloc(sizeof (*envlist))) == NULL)
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return (NULL);
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LIST_INIT(&envlist->el_entries);
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envlist->el_count = 0;
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return (envlist);
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}
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/*
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* Releases given envlist and its entries.
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*/
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void
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envlist_free(envlist_t *envlist)
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{
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struct envlist_entry *entry;
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assert(envlist != NULL);
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while (envlist->el_entries.lh_first != NULL) {
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entry = envlist->el_entries.lh_first;
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LIST_REMOVE(entry, ev_link);
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free((char *)entry->ev_var);
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free(entry);
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}
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free(envlist);
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}
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/*
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* Parses comma separated list of set/modify environment
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* variable entries and updates given enlist accordingly.
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*
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* For example:
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* envlist_parse(el, "HOME=foo,SHELL=/bin/sh");
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*
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* inserts/sets environment variables HOME and SHELL.
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*
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* Returns 0 on success, errno otherwise.
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*/
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int
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envlist_parse_set(envlist_t *envlist, const char *env)
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{
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return (envlist_parse(envlist, env, &envlist_setenv));
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}
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/*
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* Parses comma separated list of unset environment variable
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* entries and removes given variables from given envlist.
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*
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* Returns 0 on success, errno otherwise.
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*/
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int
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envlist_parse_unset(envlist_t *envlist, const char *env)
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{
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return (envlist_parse(envlist, env, &envlist_unsetenv));
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}
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/*
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* Parses comma separated list of set, modify or unset entries
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* and calls given callback for each entry.
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*
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* Returns 0 in case of success, errno otherwise.
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*/
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static int
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envlist_parse(envlist_t *envlist, const char *env,
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int (*callback)(envlist_t *, const char *))
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{
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char *tmpenv, *envvar;
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char *envsave = NULL;
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assert(callback != NULL);
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if ((envlist == NULL) || (env == NULL))
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return (EINVAL);
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/*
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* We need to make temporary copy of the env string
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* as strtok_r(3) modifies it while it tokenizes.
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*/
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if ((tmpenv = strdup(env)) == NULL)
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return (errno);
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envvar = strtok_r(tmpenv, ",", &envsave);
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while (envvar != NULL) {
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if ((*callback)(envlist, envvar) != 0) {
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free(tmpenv);
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return (errno);
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}
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envvar = strtok_r(NULL, ",", &envsave);
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}
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free(tmpenv);
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return (0);
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}
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/*
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* Sets environment value to envlist in similar manner
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* than putenv(3).
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*
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* Returns 0 in success, errno otherwise.
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*/
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int
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envlist_setenv(envlist_t *envlist, const char *env)
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{
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struct envlist_entry *entry = NULL;
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const char *eq_sign;
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size_t envname_len;
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if ((envlist == NULL) || (env == NULL))
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return (EINVAL);
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/* find out first equals sign in given env */
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if ((eq_sign = strchr(env, '=')) == NULL)
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return (EINVAL);
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envname_len = eq_sign - env + 1;
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/*
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* If there already exists variable with given name
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* we remove and release it before allocating a whole
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* new entry.
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*/
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for (entry = envlist->el_entries.lh_first; entry != NULL;
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entry = entry->ev_link.le_next) {
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if (strncmp(entry->ev_var, env, envname_len) == 0)
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break;
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}
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if (entry != NULL) {
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LIST_REMOVE(entry, ev_link);
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free((char *)entry->ev_var);
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free(entry);
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} else {
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envlist->el_count++;
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}
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if ((entry = malloc(sizeof (*entry))) == NULL)
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return (errno);
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if ((entry->ev_var = strdup(env)) == NULL) {
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free(entry);
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return (errno);
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}
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LIST_INSERT_HEAD(&envlist->el_entries, entry, ev_link);
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return (0);
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}
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/*
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* Removes given env value from envlist in similar manner
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* than unsetenv(3). Returns 0 in success, errno otherwise.
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*/
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int
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envlist_unsetenv(envlist_t *envlist, const char *env)
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{
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struct envlist_entry *entry;
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size_t envname_len;
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if ((envlist == NULL) || (env == NULL))
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return (EINVAL);
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/* env is not allowed to contain '=' */
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if (strchr(env, '=') != NULL)
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return (EINVAL);
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/*
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* Find out the requested entry and remove
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* it from the list.
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*/
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envname_len = strlen(env);
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for (entry = envlist->el_entries.lh_first; entry != NULL;
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entry = entry->ev_link.le_next) {
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if (strncmp(entry->ev_var, env, envname_len) == 0)
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break;
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}
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if (entry != NULL) {
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LIST_REMOVE(entry, ev_link);
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free((char *)entry->ev_var);
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free(entry);
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envlist->el_count--;
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}
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return (0);
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}
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/*
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* Returns given envlist as array of strings (in same form that
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* global variable environ is). Caller must free returned memory
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* by calling free(3) for each element and for the array. Returned
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* array and given envlist are not related (no common references).
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*
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* If caller provides count pointer, number of items in array is
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* stored there. In case of error, NULL is returned and no memory
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* is allocated.
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*/
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char **
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envlist_to_environ(const envlist_t *envlist, size_t *count)
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{
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struct envlist_entry *entry;
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char **env, **penv;
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penv = env = malloc((envlist->el_count + 1) * sizeof (char *));
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if (env == NULL)
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return (NULL);
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for (entry = envlist->el_entries.lh_first; entry != NULL;
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entry = entry->ev_link.le_next) {
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*(penv++) = strdup(entry->ev_var);
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}
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*penv = NULL; /* NULL terminate the list */
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if (count != NULL)
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*count = envlist->el_count;
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return (env);
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}
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@ -0,0 +1,22 @@
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#ifndef ENVLIST_H
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#define ENVLIST_H
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#ifdef __cplusplus
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extern "C" {
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#endif
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typedef struct envlist envlist_t;
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extern envlist_t *envlist_create(void);
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extern void envlist_free(envlist_t *);
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extern int envlist_setenv(envlist_t *, const char *);
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extern int envlist_unsetenv(envlist_t *, const char *);
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extern int envlist_parse_set(envlist_t *, const char *);
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extern int envlist_parse_unset(envlist_t *, const char *);
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extern char **envlist_to_environ(const envlist_t *, size_t *);
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#ifdef __cplusplus
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}
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#endif
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#endif /* ENVLIST_H */
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@ -32,6 +32,9 @@
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/* For tb_lock */
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#include "exec-all.h"
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#include "envlist.h"
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#define DEBUG_LOGFILE "/tmp/qemu.log"
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static const char *interp_prefix = CONFIG_QEMU_PREFIX;
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@ -2186,6 +2189,8 @@ static void usage(void)
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"-s size set the stack size in bytes (default=%ld)\n"
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"-cpu model select CPU (-cpu ? for list)\n"
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"-drop-ld-preload drop LD_PRELOAD for target process\n"
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"-E var=value sets/modifies targets environment variable(s)\n"
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"-U var unsets targets environment variable(s)\n"
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"\n"
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"Debug options:\n"
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"-d options activate log (logfile=%s)\n"
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@ -2195,6 +2200,12 @@ static void usage(void)
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"Environment variables:\n"
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"QEMU_STRACE Print system calls and arguments similar to the\n"
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" 'strace' program. Enable by setting to any value.\n"
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"You can use -E and -U options to set/unset environment variables\n"
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"for target process. It is possible to provide several variables\n"
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"by repeating the option. For example:\n"
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" -E var1=val2 -E var2=val2 -U LD_PRELOAD -U LD_DEBUG\n"
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"Note that if you provide several changes to single variable\n"
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"last change will stay in effect.\n"
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,
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TARGET_ARCH,
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interp_prefix,
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@ -2229,8 +2240,8 @@ int main(int argc, char **argv, char **envp)
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int optind;
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const char *r;
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int gdbstub_port = 0;
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int drop_ld_preload = 0, environ_count = 0;
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char **target_environ, **wrk, **dst;
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char **target_environ, **wrk;
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envlist_t *envlist = NULL;
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if (argc <= 1)
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usage();
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@ -2240,6 +2251,16 @@ int main(int argc, char **argv, char **envp)
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/* init debug */
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cpu_set_log_filename(DEBUG_LOGFILE);
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if ((envlist = envlist_create()) == NULL) {
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(void) fprintf(stderr, "Unable to allocate envlist\n");
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exit(1);
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}
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/* add current environment into the list */
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for (wrk = environ; *wrk != NULL; wrk++) {
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(void) envlist_setenv(envlist, *wrk);
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}
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cpu_model = NULL;
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optind = 1;
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for(;;) {
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@ -2269,6 +2290,14 @@ int main(int argc, char **argv, char **envp)
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exit(1);
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}
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cpu_set_log(mask);
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} else if (!strcmp(r, "E")) {
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r = argv[optind++];
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if (envlist_setenv(envlist, r) != 0)
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usage();
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} else if (!strcmp(r, "U")) {
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r = argv[optind++];
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if (envlist_unsetenv(envlist, r) != 0)
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usage();
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} else if (!strcmp(r, "s")) {
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r = argv[optind++];
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x86_stack_size = strtol(r, (char **)&r, 0);
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@ -2301,7 +2330,7 @@ int main(int argc, char **argv, char **envp)
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_exit(1);
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}
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} else if (!strcmp(r, "drop-ld-preload")) {
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drop_ld_preload = 1;
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(void) envlist_unsetenv(envlist, "LD_PRELOAD");
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} else if (!strcmp(r, "strace")) {
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do_strace = 1;
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} else
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@ -2369,19 +2398,8 @@ int main(int argc, char **argv, char **envp)
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do_strace = 1;
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}
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wrk = environ;
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while (*(wrk++))
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environ_count++;
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target_environ = malloc((environ_count + 1) * sizeof(char *));
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if (!target_environ)
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abort();
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for (wrk = environ, dst = target_environ; *wrk; wrk++) {
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if (drop_ld_preload && !strncmp(*wrk, "LD_PRELOAD=", 11))
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continue;
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*(dst++) = strdup(*wrk);
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}
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*dst = NULL; /* NULL terminate target_environ */
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target_environ = envlist_to_environ(envlist, NULL);
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envlist_free(envlist);
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if (loader_exec(filename, argv+optind, target_environ, regs, info) != 0) {
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printf("Error loading %s\n", filename);
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