[Qemu-devel] [PATCH] introduce environment variables for all qemu-user options

[j.schauer@email.de]

From: Johannes Schauer <j.schauer@email.de>

A first try to introduce a generic setup for mapping environment variables to
command line options.

I'm afraid to code something for platforms I can't do runtime tests on, so this 
is only for linux-user for now.

Signed-off-by: Johannes Schauer <j.schauer@email.de>
---
 linux-user/main.c |  147 +++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 files changed, 144 insertions(+), 3 deletions(-)

diff --git a/linux-user/main.c b/linux-user/main.c
index dbba8be..fb986e3 100644
--- a/linux-user/main.c
+++ b/linux-user/main.c
@@ -2640,26 +2640,51 @@ static void usage(void)
            "-E var=value      sets/modifies targets environment variable(s)\n"
            "-U var            unsets targets environment variable(s)\n"
            "-0 argv0          forces target process argv[0] to be argv0\n"
+           "-r uname          set qemu uname release string\n"
 #if defined(CONFIG_USE_GUEST_BASE)
            "-B address        set guest_base address to address\n"
            "-R size           reserve size bytes for guest virtual address space\n"
 #endif
            "\n"
+           "Standard environment variables:\n"
+           "QEMU_GDB          see the -g option\n"
+           "QEMU_LD_PREFIX    see the -L option\n"
+           "QEMU_STACK_SIZE   see the -s option\n"
+           "QEMU_CPU          see the -cpu option\n"
+           "QEMU_SET_ENV      see the -E option, comma separated list of arguments\n"
+           "QEMU_UNSET_ENV    see the -U option, comma separated list of arguments\n"
+           "QEMU_ARGV0        see the -0 option\n"
+           "QEMU_UNAME        see the -r option\n"
+#if defined(CONFIG_USE_GUEST_BASE)
+           "QEMU_GUEST_BASE   see the -B option\n"
+           "QEMU_RESERVED_VA  see the -R option\n"
+#endif
+           "\n"
            "Debug options:\n"
            "-d options   activate log (logfile=%s)\n"
            "-p pagesize  set the host page size to 'pagesize'\n"
            "-singlestep  always run in singlestep mode\n"
            "-strace      log system calls\n"
            "\n"
-           "Environment variables:\n"
-           "QEMU_STRACE       Print system calls and arguments similar to the\n"
-           "                  'strace' program.  Enable by setting to any value.\n"
+           "Debug environment variables:\n"
+           "QEMU_LOG          see the -d option\n"
+           "QEMU_PAGESIZE     see the -p option\n"
+           "QEMU_SINGLESTEP   see the -singlestep option\n"
+           "QEMU_STRACE       see the -strace option\n"
+           "\n"
            "You can use -E and -U options to set/unset environment variables\n"
            "for target process.  It is possible to provide several variables\n"
            "by repeating the option.  For example:\n"
            "    -E var1=val2 -E var2=val2 -U LD_PRELOAD -U LD_DEBUG\n"
            "Note that if you provide several changes to single variable\n"
            "last change will stay in effect.\n"
+           "Using the environment variables QEMU_SET_ENV and QEMU_UNSET_ENV\n"
+           "to set/unset environment variables for target process is\n"
+           "possible by a comma separated list of values in getsubopt(3)\n"
+           "style. For example:\n"
+           "    QEMU_SET_ENV=var1=val2,var2=val2 QEMU_UNSET_ENV=LD_PRELOAD,LD_DEBUG\n"
+           "Note that if you provide several changes to single variable\n"
+           "last change will stay in effect.\n"
            ,
            TARGET_ARCH,
            interp_prefix,
@@ -2758,6 +2783,122 @@ int main(int argc, char **argv, char **envp)
     cpudef_setup(); /* parse cpu definitions in target config file (TBD) */
 #endif
 
+    if ((r = getenv("QEMU_LOG")) != NULL) {
+        int mask;
+        const CPULogItem *item;
+        mask = cpu_str_to_log_mask(r);
+        if (!mask) {
+            printf("Log items (comma separated):\n");
+            for(item = cpu_log_items; item->mask != 0; item++) {
+                printf("%-10s %s\n", item->name, item->help);
+            }
+            exit(1);
+        }
+        cpu_set_log(mask);
+    }
+    if ((r = getenv("QEMU_SET_ENV")) != NULL) {
+        char *p, *token;
+        p = strdup(r);
+        while ((token = strsep(&p, ",")) != NULL) {
+            if (envlist_setenv(envlist, token) != 0)
+                usage();
+        }
+        free(p);
+    }
+    if ((r = getenv("QEMU_UNSET_ENV")) != NULL) {
+        char *p, *token;
+        p = strdup(r);
+        while ((token = strsep(&p, ",")) != NULL) {
+            if (envlist_unsetenv(envlist, token) != 0)
+                usage();
+        }
+        free(p);
+    }
+    if ((r = getenv("QEMU_ARGV0")) != NULL) {
+        argv0 = strdup(r);
+    }
+    if ((r = getenv("QEMU_STACK_SIZE")) != NULL) {
+        guest_stack_size = strtoul(r, (char **)&r, 0);
+        if (guest_stack_size == 0)
+            usage();
+        if (*r == 'M')
+            guest_stack_size *= 1024 * 1024;
+        else if (*r == 'k' || *r == 'K')
+            guest_stack_size *= 1024;
+    }
+    if ((r = getenv("QEMU_LD_PREFIX")) != NULL) {
+        interp_prefix = strdup(r);
+    }
+    if ((r = getenv("QEMU_PAGESIZE")) != NULL) {
+        qemu_host_page_size = atoi(r);
+        if (qemu_host_page_size == 0 ||
+            (qemu_host_page_size & (qemu_host_page_size - 1)) != 0) {
+            fprintf(stderr, "page size must be a power of two\n");
+            exit(1);
+        }
+    }
+    if ((r = getenv("QEMU_GDB")) != NULL) {
+        gdbstub_port = atoi(r);
+    }
+    if ((r = getenv("QEMU_UNAME")) != NULL) {
+        qemu_uname_release = strdup(r);
+    }
+    if ((r = getenv("QEMU_CPU")) != NULL) {
+        cpu_model = strdup(r);
+        if (cpu_model == NULL || strcmp(cpu_model, "?") == 0) {
+/* XXX: implement xxx_cpu_list for targets that still miss it */
+#if defined(cpu_list_id)
+            cpu_list_id(stdout, &fprintf, "");
+#elif defined(cpu_list)
+            cpu_list(stdout, &fprintf); /* deprecated */
+#endif
+            exit(1);
+        }
+    }
+#if defined(CONFIG_USE_GUEST_BASE)
+    if ((r = getenv("QEMU_GUEST_BASE")) != NULL) {
+       guest_base = strtol(r, NULL, 0);
+       have_guest_base = 1;
+    }
+    if ((r = getenv("QEMU_QEMU_RESERVED_VA")) != NULL) {
+        char *p;
+        int shift = 0;
+        reserved_va = strtoul(r, &p, 0);
+        switch (*p) {
+        case 'k':
+        case 'K':
+            shift = 10;
+            break;
+        case 'M':
+            shift = 20;
+            break;
+        case 'G':
+            shift = 30;
+            break;
+        }
+        if (shift) {
+            unsigned long unshifted = reserved_va;
+            p++;
+            reserved_va <<= shift;
+            if (((reserved_va >> shift) != unshifted)
+#if HOST_LONG_BITS > TARGET_VIRT_ADDR_SPACE_BITS
+                || (reserved_va > (1ul << TARGET_VIRT_ADDR_SPACE_BITS))
+#endif
+                ) {
+                fprintf(stderr, "Reserved virtual address too big\n");
+                exit(1);
+            }
+        }
+        if (*p) {
+            fprintf(stderr, "Unrecognised -R size suffix '%s'\n", p);
+            exit(1);
+        }
+    }
+#endif
+    if ((r = getenv("QEMU_SINGLESTEP")) != NULL) {
+        singlestep = 1;
+    }
+
     optind = 1;
     for(;;) {
         if (optind >= argc)
-- 
1.7.5.4