Why nm shows no symbols for /lib/i386-linux-gnu/libc.so.6?
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I expected to see number of symbols in the libc.so.6 file including printf. I used the nm tool to find them, however it says there is no symbol in libc.so.6.
linux shared-library symbol-table nm
edited May 12 '16 at 2:50
Jeff Schaller
34.2k951113
asked May 11 '16 at 20:48
masec
12019
add a comment |Â
up vote
16
down vote
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I expected to see number of symbols in the libc.so.6 file including printf. I used the nm tool to find them, however it says there is no symbol in libc.so.6.
linux shared-library symbol-table nm
edited May 12 '16 at 2:50
Jeff Schaller
34.2k951113
asked May 11 '16 at 20:48
masec
12019
Does not matter. But it is Debian.
– masec
May 14 '16 at 5:14
add a comment |Â
up vote
16
down vote
favorite
up vote
16
down vote
favorite
I expected to see number of symbols in the libc.so.6 file including printf. I used the nm tool to find them, however it says there is no symbol in libc.so.6.
linux shared-library symbol-table nm
edited May 12 '16 at 2:50
Jeff Schaller
34.2k951113
asked May 11 '16 at 20:48
masec
12019
I expected to see number of symbols in the libc.so.6 file including printf. I used the nm tool to find them, however it says there is no symbol in libc.so.6.
linux shared-library symbol-table nm
linux shared-library symbol-table nm
edited May 12 '16 at 2:50
Jeff Schaller
34.2k951113
asked May 11 '16 at 20:48
masec
12019
edited May 12 '16 at 2:50
Jeff Schaller
34.2k951113
asked May 11 '16 at 20:48
masec
12019
edited May 12 '16 at 2:50
Jeff Schaller
34.2k951113
edited May 12 '16 at 2:50
Jeff Schaller
34.2k951113
edited May 12 '16 at 2:50
Jeff Schaller
34.2k951113
34.2k951113
asked May 11 '16 at 20:48
masec
12019
asked May 11 '16 at 20:48
masec
12019
asked May 11 '16 at 20:48
masec
12019
12019
Does not matter. But it is Debian.
– masec
May 14 '16 at 5:14
add a comment |Â
Does not matter. But it is Debian.
– masec
May 14 '16 at 5:14
Does not matter. But it is Debian.
– masec
May 14 '16 at 5:14
Does not matter. But it is Debian.
– masec
May 14 '16 at 5:14
add a comment |Â
3 Answers
3
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up vote
31
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accepted
It's probably got its regular symbols stripped and what's left is its dynamic symbols, which you can get with nm -D.
answered May 11 '16 at 20:53
PSkocik
17.4k34893
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up vote
0
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Find out if it is a shared object, or, a regular ASCII file. If it is a shared object you should see "ELF 32-bit LSB shared object,"
file /lib/i386-linux-gnu/libc.so.6
answered May 11 '16 at 22:16
jncc99
364
libc.so.6is oviously a shared object.
– Gilles
May 11 '16 at 22:24
I never assume in a Linux environment. Considering someone could have touched the root directories. Yes, by name it is obviously a share object. And, it doesn't hurt to verify; when you are not getting the expected output.
– jncc99
May 11 '16 at 23:42
add a comment |Â
up vote
0
down vote
@PSkocik answered this. I just want to add more detail. There are two kinds of symbol sections in ELF: .symtab and .dynsym (see LSB_5.0.0 for detail). .symtab is for the linking step of the shared lib itself. Once linking is finished, .symtab section is not needed anymore. .dynsym section contains important symbols that are supposed to be searched by dynamic linker at running time. nm by default only dump symbols in .symtab section.
LSB_5.0.0 10.2.2.1 says a conforming shared lib should have either .symtab or .dynsym but not both. As part of the ABI library, libc is stripped out of the .symtab to be spec conforming.
answered 4 mins ago
kula85
1
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kula85 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
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3 Answers
3
active
oldest
votes
3 Answers
3
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
31
down vote
accepted
It's probably got its regular symbols stripped and what's left is its dynamic symbols, which you can get with nm -D.
answered May 11 '16 at 20:53
PSkocik
17.4k34893
add a comment |Â
up vote
31
down vote
accepted
It's probably got its regular symbols stripped and what's left is its dynamic symbols, which you can get with nm -D.
answered May 11 '16 at 20:53
PSkocik
17.4k34893
add a comment |Â
up vote
31
down vote
accepted
up vote
31
down vote
accepted
It's probably got its regular symbols stripped and what's left is its dynamic symbols, which you can get with nm -D.
answered May 11 '16 at 20:53
PSkocik
17.4k34893
It's probably got its regular symbols stripped and what's left is its dynamic symbols, which you can get with nm -D.
answered May 11 '16 at 20:53
PSkocik
17.4k34893
answered May 11 '16 at 20:53
PSkocik
17.4k34893
answered May 11 '16 at 20:53
PSkocik
17.4k34893
answered May 11 '16 at 20:53
PSkocik
17.4k34893
17.4k34893
add a comment |Â
add a comment |Â
up vote
0
down vote
Find out if it is a shared object, or, a regular ASCII file. If it is a shared object you should see "ELF 32-bit LSB shared object,"
file /lib/i386-linux-gnu/libc.so.6
answered May 11 '16 at 22:16
jncc99
364
libc.so.6is oviously a shared object.
– Gilles
May 11 '16 at 22:24
I never assume in a Linux environment. Considering someone could have touched the root directories. Yes, by name it is obviously a share object. And, it doesn't hurt to verify; when you are not getting the expected output.
– jncc99
May 11 '16 at 23:42
add a comment |Â
up vote
0
down vote
Find out if it is a shared object, or, a regular ASCII file. If it is a shared object you should see "ELF 32-bit LSB shared object,"
file /lib/i386-linux-gnu/libc.so.6
answered May 11 '16 at 22:16
jncc99
364
libc.so.6is oviously a shared object.
– Gilles
May 11 '16 at 22:24
I never assume in a Linux environment. Considering someone could have touched the root directories. Yes, by name it is obviously a share object. And, it doesn't hurt to verify; when you are not getting the expected output.
– jncc99
May 11 '16 at 23:42
add a comment |Â
up vote
0
down vote
up vote
0
down vote
Find out if it is a shared object, or, a regular ASCII file. If it is a shared object you should see "ELF 32-bit LSB shared object,"
file /lib/i386-linux-gnu/libc.so.6
answered May 11 '16 at 22:16
jncc99
364
Find out if it is a shared object, or, a regular ASCII file. If it is a shared object you should see "ELF 32-bit LSB shared object,"
file /lib/i386-linux-gnu/libc.so.6
answered May 11 '16 at 22:16
jncc99
364
answered May 11 '16 at 22:16
jncc99
364
answered May 11 '16 at 22:16
jncc99
364
answered May 11 '16 at 22:16
jncc99
364
364
libc.so.6is oviously a shared object.
– Gilles
May 11 '16 at 22:24
I never assume in a Linux environment. Considering someone could have touched the root directories. Yes, by name it is obviously a share object. And, it doesn't hurt to verify; when you are not getting the expected output.
– jncc99
May 11 '16 at 23:42
add a comment |Â
libc.so.6is oviously a shared object.
– Gilles
May 11 '16 at 22:24
I never assume in a Linux environment. Considering someone could have touched the root directories. Yes, by name it is obviously a share object. And, it doesn't hurt to verify; when you are not getting the expected output.
– jncc99
May 11 '16 at 23:42
libc.so.6 is oviously a shared object.– Gilles
May 11 '16 at 22:24
libc.so.6 is oviously a shared object.– Gilles
May 11 '16 at 22:24
I never assume in a Linux environment. Considering someone could have touched the root directories. Yes, by name it is obviously a share object. And, it doesn't hurt to verify; when you are not getting the expected output.
– jncc99
May 11 '16 at 23:42
I never assume in a Linux environment. Considering someone could have touched the root directories. Yes, by name it is obviously a share object. And, it doesn't hurt to verify; when you are not getting the expected output.
– jncc99
May 11 '16 at 23:42
add a comment |Â
up vote
0
down vote
@PSkocik answered this. I just want to add more detail. There are two kinds of symbol sections in ELF: .symtab and .dynsym (see LSB_5.0.0 for detail). .symtab is for the linking step of the shared lib itself. Once linking is finished, .symtab section is not needed anymore. .dynsym section contains important symbols that are supposed to be searched by dynamic linker at running time. nm by default only dump symbols in .symtab section.
LSB_5.0.0 10.2.2.1 says a conforming shared lib should have either .symtab or .dynsym but not both. As part of the ABI library, libc is stripped out of the .symtab to be spec conforming.
answered 4 mins ago
kula85
1
New contributor
kula85 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
add a comment |Â
up vote
0
down vote
@PSkocik answered this. I just want to add more detail. There are two kinds of symbol sections in ELF: .symtab and .dynsym (see LSB_5.0.0 for detail). .symtab is for the linking step of the shared lib itself. Once linking is finished, .symtab section is not needed anymore. .dynsym section contains important symbols that are supposed to be searched by dynamic linker at running time. nm by default only dump symbols in .symtab section.
LSB_5.0.0 10.2.2.1 says a conforming shared lib should have either .symtab or .dynsym but not both. As part of the ABI library, libc is stripped out of the .symtab to be spec conforming.
answered 4 mins ago
kula85
1
New contributor
kula85 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
add a comment |Â
up vote
0
down vote
up vote
0
down vote
@PSkocik answered this. I just want to add more detail. There are two kinds of symbol sections in ELF: .symtab and .dynsym (see LSB_5.0.0 for detail). .symtab is for the linking step of the shared lib itself. Once linking is finished, .symtab section is not needed anymore. .dynsym section contains important symbols that are supposed to be searched by dynamic linker at running time. nm by default only dump symbols in .symtab section.
LSB_5.0.0 10.2.2.1 says a conforming shared lib should have either .symtab or .dynsym but not both. As part of the ABI library, libc is stripped out of the .symtab to be spec conforming.
answered 4 mins ago
kula85
1
New contributor
kula85 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
@PSkocik answered this. I just want to add more detail. There are two kinds of symbol sections in ELF: .symtab and .dynsym (see LSB_5.0.0 for detail). .symtab is for the linking step of the shared lib itself. Once linking is finished, .symtab section is not needed anymore. .dynsym section contains important symbols that are supposed to be searched by dynamic linker at running time. nm by default only dump symbols in .symtab section.
LSB_5.0.0 10.2.2.1 says a conforming shared lib should have either .symtab or .dynsym but not both. As part of the ABI library, libc is stripped out of the .symtab to be spec conforming.
answered 4 mins ago
kula85
1
New contributor
kula85 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
answered 4 mins ago
kula85
1
New contributor
kula85 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
answered 4 mins ago
kula85
1
answered 4 mins ago
kula85
1
1
New contributor
kula85 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
New contributor
kula85 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
kula85 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
add a comment |Â
add a comment |Â
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Does not matter. But it is Debian.
– masec
May 14 '16 at 5:14