| 1 | #include <kernel/OS.h>
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| 2 | #include <kernel/image.h>
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| 3 |
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| 4 | #include <stdio.h>
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| 5 |
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| 6 | /* This program outputs information about its own areas, illustrating how
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| 7 | * runtime_loader randomly positions (or not) program segments read
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| 8 | * from executables on disk.
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| 9 | *
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| 10 | * To compile as a position-independent ("DYN") executable:
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| 11 | *
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| 12 | * gcc -o relocation-test relocation-test.c
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| 13 | *
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| 14 | * To compile as a fixed-position ("EXEC") executable (until gcc is patched):
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| 15 | *
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| 16 | * gcc -### -fno-pie -o relocation-test relocation-test.c 2>&1 \
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| 17 | * | grep '^\s' | sed -e 's/-shared//g' | bash -s
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| 18 | *
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| 19 | * The current runtime_loader will execute the program when it is built as a
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| 20 | * position-independent executable. When it's built as a fixed-position
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| 21 | * executable runtime_loader will erroneously insist on relocating the
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| 22 | * program's code anyway, leading to a crash.
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| 23 | *
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| 24 | * With the patch applied runtime_loader will execute the program correctly in
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| 25 | * both cases.
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| 26 | *
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| 27 | * Compare this program's output to the output of "readelf -l relocation-test"
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| 28 | * to see how this program's LOAD segments (prefixed in memory with
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| 29 | * "relocation-test_seg") are randomly positioned in the first case but loaded
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| 30 | * at a fixed address (matching the position specified in the ELF header,
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| 31 | * rounded down to the closest page boundary) in the latter.
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| 32 | */
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| 33 |
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| 34 | int
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| 35 | main (int argc, char **argv) {
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| 36 | int32 image_cookie = 0;
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| 37 | image_info i_info;
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| 38 |
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| 39 | ssize_t area_cookie = 0;
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| 40 | area_info a_info;
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| 41 | uint area_number = 0;
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| 42 |
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| 43 | /* Find our app image */
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| 44 | while (get_next_image_info(0, &image_cookie, &i_info) == B_OK)
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| 45 | if (i_info.type == B_APP_IMAGE)
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| 46 | /* Output information about where our areas (including our text and
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| 47 | * data segments) were loaded */
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| 48 | while (get_next_area_info (0, &area_cookie, &a_info) == B_OK)
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| 49 | printf (" %2i: %s (%s%s)\n"
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| 50 | " Addr: %018p Size: 0x%08zx RAM: 0x%08x\n"
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| 51 | "\n",
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| 52 | ++area_number,
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| 53 | a_info.name,
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| 54 | (a_info.protection & B_READ_AREA ? "r" : ""),
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| 55 | (a_info.protection & B_WRITE_AREA ? "w" : "o"),
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| 56 | a_info.address,
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| 57 | a_info.size,
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| 58 | a_info.ram_size);
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| 59 |
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| 60 | return 0;
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| 61 | }
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